Anterior cruciate ligament injuries of the knee

Anatomy

The anterior cruciate ligament's (ACL) name is derived from its anterior insertion on the tibial plateau and the fact that it "crosses" the posterior cruciate ligament within the intercondylar notch ( Latin: crux, cruc-, cross). The femoral attachment is at the posteromedial aspect of the lateral femoral condyle. The tibial attachment is larger and more stable than its attachment to the femur and is located medial to the insertion site of the anterior horn of the lateral meniscus, 15mm posterior to the anterior border of the tibial articular surface [1] . The ACL itself consists of two bundles named after their tibial insertion sites, the anteromedial (AM) bundle and the posterolateral (PL) bundle . The AM bundle tightens when the knee is in flexion. The PL bundle tightens when the knee is in extension and also tightens during internal and external rotation of the tibia. The primary blood supply is the middle geniculate artery which enters the ligament near its femoral attachment after entering the posterior capsule. There is collateral blood supply from the medial and lateral geniculate arteries. The innervation of the ACL is from the tibial nerve via the posterior articular branch, which is primarily vasomotor in function. Mechanoreceptors and possibly pain fibers are present as well. The typical size of the ligament anywhere from 30mm to 37mm in length and an averages 40mm squared in cross section at midsubstance.

Biomechanics

Function

Primary function: I provided approximately 85% of the resistance to anterior tibial translation
Secondary functions include restraint to varus/valgus forces and it provides rotational stability through the posterolateral bundle

Pathogenesis

Most injuries are secondary to low energy mechanisms.
- Two thirds of the injuries are the result of a noncontact injury (hyperextension or pivoting). This is the type of injury often seen in athletes of "cutting" sports such as soccer, skiing, and football.
- Direct contact injuries often induce a hyperextension or valgus stress on the knee that leads to a cruciate injury.
High energy mechanisms, such as motor vehicle accidents are often associated with concurrent injuries.
Compared to males, females have a decreased protective role of dynamic knee stabilizers, decreased ability to resist anterior tibial translation with muscle co-contraction, a smaller ACL, and decreased intercondylar notch width index [2]. Additionally, females may be at increased risk of ACL injury during different phases of the menstrual cycle ¹ ² . Female basketball players have up to a 3.5 incidence ratio of ACL tears compared to males. For soccer players the ratio is 2.67, lacrosse players 1.18, and for Alpine skiing 1.0 ³ .

Natural History

Damage to extraarticular ligaments results in a local hematoma which leads to the formation fibrinogen mesh, accumulation of inflammatory cells, granulation tissue, and ultimately fibrous tissue that restores function to the ligament. This is partially made possible by the surrounding soft tissues that contain the hematoma, allowing this cascade of events to occur. The cruciates, however, are only surrounded by a thin synovial membrane. This membrane may be preserved in partial rupture, thereby providing containment of the hematoma and allowing some degree of fibrous tissue formation. In complete tears this membrane ruptures, allowing the hematoma to dissipate throughout the joint and prohibiting the formation of fibrous scar tissue. Therefore, a functional ACL can only be restored by operative intervention in the setting of a complete tear.

One prospective randomized study comparing nonoperative management with ACL repair or reconstruction showed no difference in rates of radiographic osteoarthritis at 15 years followup. However, 1/3 of patients in the nonoperative group required surgical reconstruction due to persistent instability. The status of the menisci was the strongest predictor for the development of osteoarthritis. If a meniscectomy was performed, 2/3 of the patients developed radiographic osteoarthritis regardless of the ACL treatment group ⁴ .

However, it has been shown that ACL reconstruction decreases the risk of future meniscal injury when compared to nonoperative management ⁵ . Thus, theoretically, ACL reconstruction should indirectly decrease the risk of developing premature osteoarthritis.

Patient History and Physical Findings

History - Two thirds of the injuries are the result of a non contact injury (deceleration or pivoting) and are often associated with a "pop" and swelling, which is typically seen within 4-12 hours fo the injury. (Other knee injuries associated with a hemarthrosis include posterior cruciate tear, peripheral meniscus tear, osteochondral fracture, capsular injury, and patellar dislocation. Direct contact injuries often induce a hyperextension or valgus stress on the knee that leads to a cruciate injury. Other questions include ability to bear weight? Did the patient continue play? Symptoms of instability? Other factors to consider include pre-injury activity level, job activities, and future plans, as this information will aid in decision making.
Examination - Clinical examination is at least as accurate as MRI for the diagnosis of ACL tear in the hands of a skilled examiner ⁶ . Examination immediately after the injury is typically more accurate than after the onset of swelling, pain, and subsequent guarding.
Observation: malalignment may be suggestive of a fracture. Swelling typically appears by 4 hours.
Palpation: effusion? concurrent injuries?
Range of motion (active and passive)
Stability testing: AP, varus, valgus, rotational.
- Lachman Test: is more sensitive and used more often that he anterior drawer test for testing anteroposterior stability.
- Pivot Shift Test: findings have been reported to have high correlation with functional outcomes after ACL reconstruction ⁷ .
- Arthrometers: KT-1000 - Quantifies only anteroposterior stabiltiy. Does not quantify rotational stability.

Imaging and other Diagnostic Studies

X-ray: Useful in the diagnosis of associated injuries

Segond sign - A lateral tibial plateau avulsion is highly suggestive of an ACL tear (present in approximately 9% of ACL tears) ⁸ .
Tibial tubercle avulsion - often seen in younger patients and those with poor bone quality

MRI: Typically the diagnosis of ACL tear can be made on the basis of history and physical alone. Diagnosis can be confirmed with MRI. Reported sensitivity ranges from 90-95% and specificity from 95-100% ⁹ . Damage to ACL seen on one slice may be indicative of a complete, partial or intra-substance tear. Images must be reviewed in all planes to confirm diagnosis. Positive signs on MRI suggestive for complete ACL tear include ⁹ :

Direct signs:
- A poorly demonstrated or lack of ACL on all sagittal images
- Well-defined mass in the intercondylar notch with high signal intensity on T2-weighted images
- ACL disruption on axial and sagittal images and failure of the ACL fascicles to parallel Blumensaat's line
- Fluid signal in the proximal ACL (common in ruptures in skiers)
Indirect signs:
- A kissing contusion, (ie a bone bruise on the posterior-lateral tibia and central lateral femur in the terminal sulcus), can occur only with pathological translation and thus suggests an ACL tear
- Anterior Drawer Sign: Present when the posterior tibial border is more than 5mm anterior to a vertical line drawn tangential to the posterior femoral condyle
- Buckled PCL: occurs when any portion of the PCL is concave posteriorly
- Posterior PCL line, coronal PCL sign, posterior femoral line, Buckling of the patella tendon

Diagnosis of Partial ACL Tears

The diagnosis of a partial tear is difficult and requires the use of a combination of history, physical exam, MRI and possibly arthrometer testing. MRI findings suggestive of a partial tear include disruption of either the AM or PL bundles, focal edema or focal thickening of the ACL, diffuse thickening of the ACL with some detectable fibrillar pattern, and lack of a bone bruise ⁹ [1]. The addition of oblique sagittal and coronal planes to MRI imaging has been shown to increase accuracy [1].

Associated Injuries

Medial collateral ligament

Lateral meniscus tears are more commonly see with combined ACL/MCL injuries than are medial meniscus injuries. A common tear pattern entails a radial split tear of the middle horn and vertical tear of the posterior horn.

Medial meniscus tears are more commonly see with chronic ACL injuries.

Differential Diagnosis

Hemarthrosis in the setting of normal x-rays can be due to an ACL tear, a patellar dislocation, a peripheral meniscal tear, or an osteochondral fracture.

Treatment of Complete ACL Tears

Nonoperative treatment: Patients should be counseled that nonoperative treatment will place them at risk of continued instability, and progressive meniscal and chondral degeneration. However, nonoperative treatment may be the best option in older, low demand patients. Treatment primarily involves aggressive quadriceps and hamstring strengthening.

Operative treatment: There is no upper age limit for consideration of operative treatment. In general, surgical reconstruction is recommended for young patient, those with high activity levels (particularly those involved in sports requiring cutting an pivoting) and those with greatly increased laxity. Reconstruction is typically performed once swelling, range of motion, pain level and quadriceps control have been optimized.

Graft Selection - A 2010 systematic review of Oxford Level I & II studies reported no difference between autograft and allograft reconstructions ¹⁰ . Likewise, a 2009 prospective randomized study reported no difference between BPTB and hamstrings tendon autograft reconstructions at minimum 2 years followup ¹¹ . However, there are many factors to consider when choosing a graft type.

Allograft reconstruction: Allografts available include bone-patellar tendon-bone, achilles tendon, quadriceps tendon, tibialis anterior, tibialis posterior, hamstring tendon grafts, and fascia lata. Advantages of allografts include no donor site morbidity and less functional limitations in the short-term ¹² . Allografts are typically preferred for the lower demand or older patient. Risks of allograft use include disease transmission and immunogenicity. Disease transmission has decreased significantly with the use of polymerase chain reaction (PCR) testing. Click here for a summary on the safety of tissue transplants published by the American Association of Tissue Banks (AATB). Currently, the AATB requires that donor tissue be screened for HIV, hepatitis B and C, syphilis, human T-cell lymphotropic virus. Additionally donor blood and tissue cultures are performed to screen for bacterial infection [1]. Cryopreservation of the allografts during preparation kills donor cells and may denature cell surface histocompatibility antigens. As a result, the host immune response is limited ¹³ .

Autograft reconstruction: Most commonly used grafts include either a "bone-patellar tendon-bone" (BPTB) autograft taken from the patient's own central 1/3 patellar tendon, quadrupled hamstring autograft consisting of the distal semitendonosis and gracillis tendons, and quadriceps tendon. Competitive football players are typically reconstructed using bone-patellar tendon-bone autograft. Competitive basketball players are typically reconstructed using hamstrings autograft in order to avoid future patellar tendon pathology in light of the jumping requirements of this sport ¹⁴ . Donor site morbidity is a factor to consider when deciding on graft type. Donor site pain, local numbness, patellar fractures, patellar tendon ruputres (rare), and patellar tendonitis may be seen after BPTB autograft reconstructions. The presence of increased anterior knee pain after BPTB autograft reconstruction compared to other methods of reconstruction is controversial. Hamstring autograft harvest may damage the infrapatellar branch of the saphenous nerve.

Single bundle vs. double bundle - Neither technique has been shown to be clinically superior to the other as of yet, however research is ongoing. Numerous studies have shown improved AP ¹⁵ and rotational stability as well as improved femoral-tibial contact area suggesting that double bundle ACL reconstruction more closely restores knee kinematics when compared to single bundle reconstruction ⁵ [1].
Graft tension - The level of intraoperative graft tensioning and knee position at which this is performed is controversial, as is preconditioning of the graft. A recent systematic review of randomized controlled trials concluded that initial graft tension does not affect clinical outcomes, regardless of graft type ¹⁶ .
Graft fixation -
- BPTB grafts most commonly employ interference screws on both the femoral and tibial side. Soft tissue grafts may be secured by a variety of methods, with no consensus as to what is the best. As a rule, fixation on the tibial side is more difficult owing to the softer bone of the plateau, parallel tibial tunnels, and a interference screw insertion direction that is counter to the direction of graft tension [1].
- A recent systematic review of randomized controlled trials concluded that bioabsorbable and titanium screws produce similar clinical results when used for hamstring and patellar tendon reconstructions. However, bioabsorbable screws interfere less with future MRI and surgery and theoretically have a lower risk of late hematogenous infection. This review also concluded that that cross pin fixation and interference screws are comparable means of fixating a hamstring tendon graft ¹⁶ .
- Techniques
  - Direct: interference screws, staples, spiked washers
  - Indirect: cross-pin, screw and post, EndoButton

Indications and contraindications

Treatment of ACL tears in the skeletally immature:

Biology of cruciate ligament reconstruction

Allografts heal in the same manner as autografts but at a much slower rate. Early tendon to bone healing involves the formation of fibrovascular scar tissue at the graft tunnel interface followed by the formation of Sharpey's fibers composed of type III collagen. Ultimately bone grows into the interface tissue and incorporates the outer portion of the graft. Soft tissue grafts typically heal to bone in 8-12 weeks. The bone to bone healing process first involve osteonecrosis of the bone plug followed by the incorporation of surrounding cancellous bone. Bone to bone healing typically occurs within 6 weeks. Intraarticularly the autograft tendon initially undergoes a period of avascular necrosis. Graft strength decreases greatly from approximately 3 weeks until 6 months after surgery. Ultimately, autograft and allograft soft tissue grafts provide scaffold for re-population by host synovial cells ¹³ . The final phase of graft incorporation involves collagen maturation. Revascularization stems from the infrapatellar fat pat and the posterior synovial tissues ¹³ . The graft never fully resembles the structure of a native ACL or that of the original tendon [1].

Pearls and Pitfalls

Tunnel malposition is one of the most common indications for revision of a single-bundle ACL. Tunnel position that is too vertical may result in insufficient rotational stability. The current trend is to place the femoral tunnel at the 10 o'clock/2 o'clock position ⁵ .

Postoperative Care

Cryotherapy - A meta-analysis has reported crytherapy to decrease postoperative pain, however it did not have an effect on range of motion or wound drainage. The study concluded that in light of the ease of use, low cost and low side effect profile, and high patient satisfaction, postoperative use of cryotherapy is justified ¹⁷ .

Bracing - Rehabilitation braces are used during the postoperative period, while functional braces are used when the patient returns to play. At least two studies have reported that rehabilitation brace locked in extension or hyperextension during the early postoperative period has been shown to prevent loss of extension ¹⁸ ¹⁹ . However, a systematic review of randomized controlled trials published in 2009 concluded that postoperative bracing neither affects clinical outcome nor reduces the risk of subsequent intra-articular injury ¹⁶ . The benefits of functional bracing is controversial [1].

Weight-bearing - Immediate weight-bearing has been reported to be associated with lower incidence of anterior knee pain and no difference in knee extension range of motion , VMO function, and AP knee laxity when compared to 2 weeks of delayed weight-bearing in 49 prospectively randomized patients undergoing BPTB autograft reconstruction ²⁰ .

Physical Therapy - In general closed kinetic chain (CKC) exercises are recommend, as they place less stress on the ACL graft compared to open kinetic chain (OKC) exercises. A review of the literature published in 2009 has concluded that CKC exercised produce less pain and risk of increased laxity and better subjective outcomes in patients who have undergone BPTB reconstructions. This comparison has not been made in patients who have undergone HS reconstructions ¹⁶ . However, numerous prospective randomized clinical studies have failed to show a significant difference between closed and open chain exercises in graft healing and functional outcomes [1]. Attention should be given to both quadriceps and hamstrings strengthening. Eccentric exercises may result in increased quadriceps and gluteus maximus volume and function at one year postoperatively ²¹ . Electrical stimulation and biofeedback have both been shown to improve recovery of quadriceps function postoperatively as well [1].

Rehab protocol - In general rehab protocols focus on early range of motion, immediate weight-bearing as tolerated, and return to sports at 6-9 months. Decision making for return to play should be made on a case by case basis. Criteria for return to play status includes range of motion, muscles strength and balance, static stability, and dynamic stability as measured by functional testing [1].

Outcome

A knee with an isolated ACL injury that has been reconstructed has a very low risk (0-13%) of developing premature osteoarthritis more that 10 years after the injury ²² . Associated meniscal injuries increase the risk to 21-48% risk for the development of premature osteoarthritis ²² . One study has reported that history of meniscectomy but not ACL reconstruction is associated with a shortened expected career in the NFL ²³ . For more info on outcomes in NBA and NFL athletes, see the following papers: ²⁴ ²⁵ .

Complications

Arthrofibrosis is the most common postoperative complication.

Persistent instability

Septic arthritis: Incidence of 0.3-1.7% ²⁶ .

Patellar fractures, patellar tendon ruputres, and patellar tendonitis may be seen after BPTB autograft reconstructions

Disease transmission from allograft tissue is extremely rare

Selected References

Fri Jul 30 09:51:36 PDT 2010

Footnotes
Ref	Notes
1	Ruedl G, Ploner P, Linortner I, Schranz A, Fink C, Sommersacher R, Pocecco E, Nachbauer W, Burtscher M, 2009. "Are oral contraceptive use and menstrual cycle phase related to anterior cruciate ligament injury risk in female recreational skiers?" Knee Surg Sports Traumatol Arthrosc 17 (9): 1065-9 [PubMed] Abstract: Oral contraceptive use and menstrual cycle phase are suggested to influence the risk of anterior cruciate ligament (ACL) injuries in female athletes. However, only few data are available for recreational sports. Therefore, female recreational skiers with a non-contact ACL injury and age-matched controls completed a self-reported questionnaire relating to menstrual history, oral contraceptive use and previous knee injuries. Menstrual history data were used to group subjects into either preovulatory or postovulatory phases of menstrual cycle. Our findings suggest that oral contraceptive use did not show any protective effect against ACL injuries nor did self-reported previous knee injuries show any association with ACL injury rate in recreational alpine skiing. Analysis of menstrual history data revealed that recreational skiers in the preovulatory phase were significantly more likely to sustain an ACL injury than were skiers in the postovulatory phase.
2	Zazulak BT, Paterno M, Myer GD, Romani WA, Hewett TE, 2006. "The effects of the menstrual cycle on anterior knee laxity: a systematic review." Sports Med 36 (10): 847-62 [PubMed] Abstract: Female athletes are at a 4- to 6-fold increased risk of anterior cruciate ligament (ACL) injury compared with male athletes. There are several medical, emotional and financial burdens associated with these injuries. Sex hormones may be involved in the ACL injury disparity, with potential associations reported between phases of the menstrual cycle and ACL injury rates. The reported relationships between ACL injury and menstrual status may be related to associated changes in ligament mechanical properties from cyclic fluctuations of female sex hormones. A PubMed electronic database literature search, including MEDLINE (1966-2005) and CINAHL (1982-2005), with the search terms 'menstrual cycle' and 'knee laxity' was used for this systematic review. Studies were included in this systematic review if they were prospective cohort studies and investigated the association between the menstrual cycle and anterior knee laxity in females. Nine prospective cohort studies, published as 11 articles, were included in the systematic review. Six of nine studies reported no significant effect of the menstrual cycle on anterior knee laxity in women. Three studies observed significant associations between the menstrual cycle and anterior knee laxity. These studies all reported the finding that laxity increased during the ovulatory or post-ovulatory phases of the cycle. A meta-analysis, which included data from all nine reviewed studies, corroborated this significant effect of cycle phase on knee laxity (F-value = 56.59, p = 0.0001). In the analyses, the knee laxity data measured at 10-14 days was >15-28 days which was >1-9 days. Future studies testing the relationship between the menstrual cycle and potentially associated parameters should consider the limitations outlined in this article and control for potential biases and confounders. Power analyses should be utilised. Subjects should be randomly entered into the studies at alternate points in the cycle, and standard and consistent data acquisition and reporting methods should be utilised. Future studies should clearly define what constitutes a 'normal' cycle and appropriate control subjects should be utilised. Furthermore, there is a need to define cycle phase (and timing within cycle phase) with actual hormone levels rather than a day of the cycle. Although hormone confirmations were provided in many of the studies that selected specific days to depict a particular cycle for all women, it is unknown from these data if they truly captured times of peak hormone values in all women. A combined systematic review and meta-analysis of the literature indicate that the menstrual cycle may have an effect on anterior-posterior laxity of the knee; however, further investigation is needed to confirm or reject this hypothesis.
3	Prodromos CC, Han Y, Rogowski J, Joyce B, Shi K, 2007. "A meta-analysis of the incidence of anterior cruciate ligament tears as a function of gender, sport, and a knee injury-reduction regimen." Arthroscopy 23 (12): 1320-1325.e6 [PubMed] Abstract: PURPOSE: The literature has shown that anterior cruciate ligament (ACL) tear rates vary by gender, by sport, and in response to injury-reduction training programs. However, there is no consensus as to the magnitudes of these tear rates or their variations as a function of these variables. For example, the female-male ACL tear ratio has been reported to be as high as 9:1. Our purpose was to apply meta-analysis to the entire applicable literature to generate accurate estimates of the true incidences of ACL tear as a function of gender, sport, and injury-reduction training. METHODS: A PubMed literature search was done to identify all studies dealing with ACL tear incidence. Bibliographic cross-referencing was done to identify additional articles. Meta-analytic principles were applied to generate ACL incidences as a function of gender, sport, and prior injury-reduction training. RESULTS: Female-male ACL tear incidences ratios were as follows: basketball, 3.5; soccer, 2.67; lacrosse, 1.18; and Alpine skiing, 1.0. The collegiate soccer tear rate was 0.32 for female subjects and 0.12 for male subjects. For basketball, the rates were 0.29 and 0.08, respectively. The rate for recreational Alpine skiers was 0.63, and that for experts was 0.03, with no gender variance. The two volleyball studies had no ACL tears. Training reduced the ACL tear incidence in soccer by 0.24 but did not reduce it at all in basketball. CONCLUSIONS: Female subjects had a roughly 3 times greater incidence of ACL tears in soccer and basketball versus male subjects. Injury-reduction programs were effective for soccer but not basketball. Recreational Alpine skiers had the highest incidences of ACL tear, whereas expert Alpine skiers had the lowest incidences. Volleyball may in fact be a low-risk sport rather than a high-risk sport. Alpine skiers and lacrosse players had no gender difference for ACL tear rate. Year-round female athletes who play soccer and basketball have an ACL tear rate of approximately 5%. LEVEL OF EVIDENCE: Level IV, therapeutic case series.
4	Meunier A, Odensten M, Good L, 2007. "Long-term results after primary repair or non-surgical treatment of anterior cruciate ligament rupture: a randomized study with a 15-year follow-up." Scand J Med Sci Sports 17 (3): 230-7 [PubMed] Abstract: We investigated the long-term outcome of 100 patients 15 years after having been randomly allocated to primary repair (augmented or non-augmented) or non-surgical treatment of an anterior cruciate ligament (ACL) rupture. The subjective outcome was similar between the groups, with no difference regarding activity level and knee-injury and osteoarthritis outcome score but with a slightly lower Lysholm score for the non-surgically treated group. This difference was attributed to more instability symptoms. The radiological osteoarthritis (OA) frequency did not differ between surgically or non-surgically treated patients, but if a meniscectomy was performed, two-thirds of the patients showed OA changes regardless of initial treatment of the ACL. There were significantly more meniscus injuries in patients initially treated non-surgically. One-third of the patients in the non-surgically treated group underwent secondary ACL reconstruction due to instability problems. In this study, ACL repair itself could not reduce the risk of OA nor increase the subjective outcome scores. However, one-third of the non-surgical treated patients were later ACL reconstructed due to instability. The status of the menisci was found to be the most important predictor of developing OA. Early ACL repair and also ACL reconstruction can reduce the risk of secondary meniscus tears. Indirectly this supports the hypothesis that early stabilization of the knee after ACL injury is advantageous for the long-term outcome.
5	Nelson JD, Hogan MV, Miller MD, 2010. "What's new in sports medicine." J Bone Joint Surg Am 92 (1): 250-63 [PubMed] [ a b c ]
6	Kocabey Y, Tetik O, Isbell WM, Atay OA, Johnson DL, 2004. "The value of clinical examination versus magnetic resonance imaging in the diagnosis of meniscal tears and anterior cruciate ligament rupture." Arthroscopy 20 (7): 696-700 [PubMed] Abstract: PURPOSE: The purpose of this study was to compare the accuracy of clinical examination versus magnetic resonance imaging (MRI) in diagnosing meniscal and anterior cruciate ligament (ACL) pathology. TYPE OF STUDY: Prospective, longitudinal study. METHODS: Between August 2001 and December 2001, we prospectively evaluated 50 consecutive patients (37 male, 13 female) with 65 pathologies of medial meniscal tears, lateral meniscal tears, and/or ACL rupture. The average preoperative period for the patients was 5 weeks (range, 5 days to 5 months) and their mean age was 22 years (range, 12 to 42 years). After initial clinical examination, the same sports medicine fellowship-trained orthopaedic surgeon (10-year practice profile of 100% sports medicine) evaluated the MRI of the patients and performed their arthroscopic procedure. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated comparing clinical examination, MRI, and arthroscopic evaluation. RESULTS: There was no statistical difference between MRI or clinical examination in diagnosing medial or lateral meniscal tears or ACL tears ( P >.05). The accuracy of the clinical examination and MRI evaluation was equal for diagnosing meniscal tears and ACL ruptures. Conclusions: A well-trained qualified surgeon can safely rely on clinical examination for diagnosing meniscal and ACL injuries. Clinical examination is at least as accurate as MRI in the skilled orthopaedic surgeon's hand. MRI should be reserved for more complicated and confusing cases. The routine ordering of an MRI scan of the knee before examination by a well-trained orthopaedic surgeon is not recommended. LEVEL OF EVIDENCE: Level II, diagnostic.
7	Kocher MS, Steadman JR, Briggs KK, Sterett WI, Hawkins RJ, 2004 Apr-May. "Relationships between objective assessment of ligament stability and subjective assessment of symptoms and function after anterior cruciate ligament reconstruction." Am J Sports Med 32 (3): 629-34 [PubMed] Abstract: BACKGROUND: Relationships between objective assessment of ligament stability and subjective assessment of symptoms and function after anterior cruciate ligament reconstruction have not been established. HYPOTHESIS: Relationships exist between objective and subjective assessments after anterior cruciate ligament reconstruction. STUDY DESIGN: Case series. METHODS: Patients (N = 202) undergoing anterior cruciate ligament reconstruction with 2-year minimum follow-up were studied. Objective variables of ligament stability at follow-up included instrumented laxity, Lachman examination, and pivot-shift examination. Subjective variables of symptoms at follow-up included pain, swelling, giving way, locking, crepitus, stiffness, and limping. Subjective function at follow-up included walking, squatting, stair climbing, running, cutting, jumping, twisting, activity limitation, sports level, activities of daily living level, work level, knee function, sports participation, Lysholm score, and satisfaction with outcome. RESULTS: Instrumented knee laxity and Lachman examination had no significant (P >.05) relationships with any subjective variables of symptoms and function. Pivot-shift examination had significant associations with satisfaction (P =.03), partial giving way (P =.01), full giving way (P =.01), difficulty cutting (P =.01), difficulty twisting (P =.01), activity limitation (P =.01), overall knee function (P =.03), sports participation (P =.02), and Lysholm score (P =.01). CONCLUSIONS: The pivot-shift examination may be a better measure of "functional instability" than instrumented knee laxity or Lachman examination after anterior cruciate ligament reconstruction.
8	Hess T, Rupp S, Hopf T, Gleitz M, Liebler J, 1994. "Lateral tibial avulsion fractures and disruptions to the anterior cruciate ligament. A clinical study of their incidence and correlation." Clin Orthop Relat Res (303): 193-7 [PubMed] Abstract: Avulsion fractures of the lateral tibial plateau, known as the lateral capsular sign, are increasingly associated with anterior cruciate ligament (ACL) ruptures. This phenomenon, known as the Ségond fracture, is a bony avulsion of the menisco-tibial ligament. Stress, which can lead to an avulsion of this kind, almost always occurs during knee flexion and internal tibial rotation, and in most cases only after damage to the primary ACL stabilizer. Examination of 151 ACL ruptures revealed a Ségond fracture in 9% of patients. Nearly all were caused by sports injuries and, understandably, the accident mechanism always included knee flexion and internal rotation of the tibial. In a similarly large number of other knee injuries without damage to the ACL, only one case of a Ségond fracture was found. This phenomenon, which is easy to detect by radiograph, can thus be regarded as a strong indication of the presence of a ligament injury.
9	Klass D, Toms AP, Greenwood R, Hopgood P, 2007. "MR imaging of acute anterior cruciate ligament injuries." Knee 14 (5): 339-47 [PubMed] Abstract: MRI of the knee has become an indispensable clinical tool in the management of chronic knee conditions. MRI for acute knee injuries is less well established but is becoming increasingly prevalent. MRI in acute ACL injuries is particularly useful for identifying associated injuries that will influence the early management of the patient. The aim of this paper is to describe the MRI findings of acute ACL tears, their commonly associated, and less common but serious associated injuries. Where available, the evidence for the sensitivity and specificity of these MRI features is presented. The contribution of these MRI findings to the management of the patient is discussed. [ a b c ]
10	Foster TE, Wolfe BL, Ryan S, Silvestri L, Kaye EK, 2010. "Does the graft source really matter in the outcome of patients undergoing anterior cruciate ligament reconstruction? An evaluation of autograft versus allograft reconstruction results: a systematic review." Am J Sports Med 38 (1): 189-99 [PubMed] Abstract: BACKGROUND: Despite the large number of anterior cruciate ligament reconstructions performed each year, there remains a significant controversy regarding the effect of the graft source on the functional outcome of patients. HYPOTHESIS: There is no difference in outcomes of autograft versus allograft anterior cruciate ligament reconstructions. STUDY DESIGN: Systematic review. METHODS: The authors systematically identified prospective studies (Oxford level of evidence I or II only) that included autograft patients, allograft patients, or both. Objective outcomes that were reported were meta-analyzed; this included pivot-shift results, KT-1000 arthrometer results, International Knee Documentation Committee (IKDC) scores, Lysholm Scores, graft failures, and postoperative complications. Two statistical analyses were performed. First a primary statistical analysis was performed comparing pooled autograft data (bone-patellar-tendon bone and hamstrings combined) and pooled allograft data (bone-patellar-tendon bone and hamstrings combined). To have a more comprehensive understanding of the differences between each specific graft source, a secondary analysis was performed without pooling the data; this directly compared the 4 types of graft sources that were studied. RESULTS: Over 400 scientific manuscripts were initially reviewed; 31 manuscripts fulfilled all of the search criteria. There were very few statistically significant differences between autograft and allograft tissue. The KT-1000 arthrometer laxity testing revealed a mean of 1.4 +/- 0.2 mm (weighted mean +/- standard error of the mean) for the allograft group compared with 1.8 +/- 0.1 mm for the autograft group (t = 2.40; P <.02). However, this difference was only for the mean score; there was no statistical significance when considering KT-1000 arthrometer measurements of greater than 3 or 5 mm. The percentage of patients receiving a final IKDC score of "A" (normal knee) was statistically significant for allograft tissue (43.9% +/- 5.5%) versus autograft tissue (28.2% +/- 1.0%) reconstructions. There was no statistically significant difference between the percentages of IKDC scores of A or B for patients receiving pooled allograft (82.9% +/- 4.2%) versus pooled autograft (87.2% +/- 0.9%) anterior cruciate ligament reconstruction (t = 1.01; P > .1). The graft failure rate was 4.7 +/- 0.5 per 100 for autograft reconstructions and 8.2 +/- 2.1 per 100 allograft reconstructions; although this may represent a trend, it is not statistically significant (t = 1.49; P > .1). The complication rate was slightly higher for autograft reconstructions at 3.5 +/- 0.4 complications per 100 autograft reconstructions compared with 2.4 +/- 1.1 complications per 100 allograft reconstructions, but not significant (t = 1.41; P > .1). CONCLUSION: After a comprehensive examination and statistical analysis of the modern literature, the authors could not identify an individual graft source that was clearly superior to the other graft sources. This led them to believe that, with currently available data, the graft source has a minimal effect on the outcome of patients undergoing anterior cruciate ligament reconstruction.
11	Taylor DC, DeBerardino TM, Nelson BJ, Duffey M, Tenuta J, Stoneman PD, Sturdivant RX, Mountcastle S, 2009. "Patellar tendon versus hamstring tendon autografts for anterior cruciate ligament reconstruction: a randomized controlled trial using similar femoral and tibial fixation methods." Am J Sports Med 37 (10): 1946-57 [PubMed] Abstract: BACKGROUND: Controversy remains over the most appropriate graft for anterior cruciate ligament reconstruction. HYPOTHESIS: There is no significant difference in outcomes after 4-strand hamstring and patellar tendon autograft anterior cruciate ligament reconstructions using similar fixation techniques. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Between August 2000 and May 2003, 64 Keller Army Hospital patients with complete anterior cruciate ligament tears were randomized to hamstring (n = 32) or patellar tendon (n = 32) autograft anterior cruciate ligament reconstruction. Operative graft fixation and rehabilitative techniques were the same for both groups. Follow-up assessments included the Single Assessment Numeric Evaluation score, Lysholm score, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score. Postoperative radiographs were analyzed for tunnel location and orientation. RESULTS: Eleven women and 53 men were randomized. Eighty-three percent of the patients (53 of 64) had follow-up of greater than 2 years, or to the point of graft rupture or removal (average follow-up, 36 months). Four hamstring grafts (12.5%) and three patellar tendon grafts (9.4%) (P = .71) ruptured. One deep infection in a hamstring graft patient necessitated graft removal. Forty-five of the 56 patients with intact grafts had greater than 2-year follow-up. Patients with patellar tendon grafts had greater Tegner activity scores (P = .04). Single Assessment Numeric Evaluation scores were 88.5 (95% confidence interval: 83.1, 93.8) and 90.1 (95% confidence interval: 85.2, 96.1) for the hamstring and patellar tendon groups, respectively (P = .53). Lysholm scores were 90.3 (95% confidence interval: 84.4, 96.1) and 90.4 (95% confidence interval: 84.5, 96.3) for the hamstring and patellar tendon groups, respectively (P = .97). There were no significant differences in knee laxity, kneeling pain, isokinetic peak torque, International Knee Documentation Committee score, or Knee Injury and Osteoarthritis Outcome Scores. Postoperative graft rupture correlated with more horizontal tibial tunnel orientation. CONCLUSION: Hamstring and patellar tendon autografts provide similar objective, subjective, and functional outcomes when assessed at least 2 years after anterior cruciate ligament reconstruction.
12	Poehling GG, Curl WW, Lee CA, Ginn TA, Rushing JT, Naughton MJ, Holden MB, Martin DF, Smith BP, 2005. "Analysis of outcomes of anterior cruciate ligament repair with 5-year follow-up: allograft versus autograft." Arthroscopy 21 (7): 774-85 [PubMed] Abstract: PURPOSE: To prospectively compare outcomes of primary anterior cruciate ligament (ACL) reconstruction with either Achilles tendon allograft with soft-tissue fixation or standard bone-patellar tendon-bone autograft with interference screw fixation. TYPE OF STUDY: Prospective comparative case series. METHODS: A group of 41 patients who underwent soft-tissue allograft reconstruction and a group of 118 patients who underwent autograft bone-patellar tendon-bone reconstruction were included in the final results. Patients were evaluated preoperatively and postoperatively at 1 to 2 weeks, 6 weeks, 3 months, 6 months, and then annually for 5 years. Objective measures of outcome included KT-1000 measurements, range of motion, ligamentous integrity, thigh atrophy, and International Knee Documentation Committee score. Subjective evaluations included patient completion of 5 questionnaires documenting functional status, pain, and health-related quality of life: (1) the short-form McGill Pain Questionnaire, (2) a patient subjective assessment of knee function and symptoms, (3) a patient subjective assessment follow-up, (4) a knee pain scale, and (5) the RAND 36-Item Health Survey. Mixed models analysis of variance was used to compare the outcomes of the treatment groups using baseline values of the study variables as a covariate. RESULTS: Autograft patients reported significantly more pain on the bodily pain subscale of the RAND-36 than the allograft group at 1 week (P = .0006), 6 weeks (P = .0007), and 3 months (P = .0270). Autograft patients reported more pain than allograft patients on the McGill Pain Scale visual analog scale at 1 to 2 weeks (P < .0001) and 6 weeks (P = .0147). Patient assessment of function and symptoms showed that a higher proportion of patients reported normal or nearly normal knee function in the allograft group than in the autograft group at 3 months (33% v 14%, P = .0558, respectively). Fewer activity limitations were reported by allograft patients than autograft patients at 6 weeks (P = .0501), 3 months (P = .0431), and 6 months (P = .0014). After reconstruction, the allograft group displayed significantly more laxity in KT-1000 measurements at all time points than the autograft group (P = .0520). These measurements decreased over time for both groups (P < .0001). CONCLUSIONS: Five-year follow-up of patients undergoing ACL reconstruction with allograft versus autograft were compared objectively and subjectively. Both groups of patients achieved similar long-term outcomes. Overall, the allograft patients reported less pain at 1 and 6 weeks after surgery, better function at 1 week, 3 months, and 1 year, and fewer activity limitations throughout the follow-up period. LEVEL OF EVIDENCE: Level II, prospective cohort study.
13	Gulotta LV, Rodeo SA, 2007. "Biology of autograft and allograft healing in anterior cruciate ligament reconstruction." Clin Sports Med 26 (4): 509-24 [PubMed] Abstract: The graft-bone attachment site is the weak link in anterior cruciate ligament (ACL) reconstruction surgery because healing is slow and often incomplete. Each of the many graft options for ACL reconstruction surgery has different healing characteristics and potential. Autografts that allow bone-to-bone healing offer the best healing potential. An understanding of the biology of graft healing should give the surgeon context in graft selection and rehabilitation for ACL reconstruction. [ a b c ]
14	Gobbi A, Mahajan S, Zanazzo M, Tuy B, 2003 Jul-Aug. "Patellar tendon versus quadrupled bone-semitendinosus anterior cruciate ligament reconstruction: a prospective clinical investigation in athletes." Arthroscopy 19 (6): 592-601 [PubMed] Abstract: PURPOSE: Patellar tendon and hamstrings are both used in anterior cruciate ligament (ACL) reconstruction, and comparisons have been reported with different results. The purpose of this clinical study was to compare the results of ACL reconstruction in athletes with 2 different graft types, both using bone-to-bone healing: bone-patellar tendon-bone graft and a quadrupled bone-semitendinosus graft. TYPE OF STUDY: Outcomes study. METHODS: From 1994 to 1997, 2 groups of 40 athletes who underwent ACL replacement with patellar tendon and quadrupled bone-semitendinosus grafts were prospectively evaluated. Preinjury activity level, age, and gender were comparable in both groups. All patients were operated on by the same surgeon within 5 months from injury and underwent group-specific rehabilitation programs. An independent examiner performed the final evaluations at 36 months. Review included clinical examination, radiographs, computed analysis, isokinetic and functional strength tests, and subjective and objective evaluation with standard knee scores. Additional procedures were recorded. Statistical analysis was performed with both parametric and nonparametric tests. RESULTS: Average surgical time was longer with the semitendinosus graft, and postoperative pain was higher in the patellar tendon group. Standard knee evaluation scores and subjective assessment revealed no significant differences. Isokinetic testing of flexion-extension and internal-external rotation showed lower quadriceps strength and a mild deficit of external rotation in the patellar tendon group and slightly lower flexor strength in the semitendinosus group at 12 months. Computerized laxity analysis showed no difference between the 2 groups with 90% of patients having less than 3 mm side-to-side difference, with a gender difference in the semitendinosus group. Kneeling pain was higher in patellar tendon group. CONCLUSIONS: The bone-patellar tendon-bone and quadrupled bone-semitendinosus autograft provide excellent grafts for ACL reconstruction. Both techniques are comparable regarding final stability, but in patients with extensor mechanism problems or those who engage in sports with a high incidence of patellar tendonitis, the semitendinosus graft should be considered.
15	Kim SJ, Jo SB, Kumar P, Oh KS, 2009. "Comparison of single- and double-bundle anterior cruciate ligament reconstruction using quadriceps tendon-bone autografts." Arthroscopy 25 (1): 70-7 [PubMed] Abstract: PURPOSE: The purpose of this study was to evaluate and compare postoperative knee stability and functional scores between single- and double- bundle anterior cruciate ligament (ACL) reconstruction with the use of quadriceps tendon-bone autografts at a 2-year follow-up. METHODS: The records of 59 patients who had ACL reconstruction between January 2005 and April 2006 were analyzed retrospectively. Twenty-eight patients had single-bundle reconstruction (group S) and 31 received double-bundle reconstruction (group D). Ligament stability was assessed with the Lachman and pivot-shift tests and a KT-2000 arthrometer. International Knee Documentation Committee (IKDC) and Lysholm scores were employed to evaluate the functional outcomes. RESULTS: The postoperative mean side-to-side difference for group S was 2.64 mm and 1.79 mm for group D, a difference that was found to be statistically significant (P = .020). Regarding the pivot-shift test, 3 patients had grade 1+ and 1 patient had grade 2+ pivot-shift in group S, while no patients had abnormal pivot-shift in group D (P = .093). The patients who reported grade A or B on IKDC scores were 24 and 28 in group S and D, respectively (P > .1). On the questionnaire of the twisting activity, although statistical difference was not found between the groups, there was a trend toward more restriction in twisting activity in group S (P = .096). We found significant correlation between the twisting activity and instability questionnaire of the Lysholm score (Spearman coefficient, 0.737; P < .001). CONCLUSIONS: Double-bundle ACL reconstruction using quadriceps tendon-bone autografts provide less laxity (1.79 mm) than single-bundle ACL reconstruction (2.64 mm) as measured by the KT-2000. However, we could not find any significant differences in the functional measurements between the 2 groups. LEVEL OF EVIDENCE: Level III, retrospective comparative study.
16	Samuelsson K, Andersson D, Karlsson J, 2009. "Treatment of anterior cruciate ligament injuries with special reference to graft type and surgical technique: an assessment of randomized controlled trials." Arthroscopy 25 (10): 1139-74 [PubMed] Abstract: PURPOSE: The primary aim was to summarize and assess current evidence from randomized controlled trials (RCTs) on anterior cruciate ligament injuries, with special reference to graft type and surgical technique. The secondary aims were to identify the relative strengths and weaknesses of the selected studies, to resolve contradictions in the literature, and to evaluate the need for further studies. METHODS: A PubMed database search using the key words "anterior cruciate ligament" was performed. The search was limited to RCTs published in English between January 1995 and March 2009. Articles on the subject of graft type and surgical technique were identified. After initial screening and a subsequent quality appraisal based on the CONSORT (Consolidated Standards of Reporting Trials) Statement, a total of 39 articles were included in this review. RESULTS: There are no differences between the bone-patellar tendon-bone (BPTB) graft and the hamstring tendon (HT) graft in terms of laxity, clinical outcome, time to return to sports, patellofemoral crepitations, 1-leg hop test, range of motion, thigh muscle circumference, or anterior knee sensory deficit. The BPTB graft produces more anterior knee pain and kneeling pain than the HT graft, but the difference disappears with time. The harvest site affects muscle strength initially but not over time. There is a possible correlation between the development of osteoarthritis and the BPTB graft. The HT graft produces more tunnel widening than the BPTB graft, but there is no correlation between tunnel widening and clinical outcome or laxity. The semitendinosus and gracilis graft is associated with inferior knee flexion at higher angles, as compared with the semitendinosus graft. There are probably no differences between the BPTB graft and the bone-HT-bone graft in terms of laxity and clinical outcome. Semitendinosus and gracilis tendon harvesting probably reduces hamstring muscle strength for approximately 1 year. Double-bundle reconstruction produces less rotatory laxity than single-bundle reconstruction. Double-bundle reconstruction by use of an 8-strand HT graft probably produces less laxity than single-bundle reconstruction. There are no differences in clinical outcome when single-bundle and double-bundle anterior cruciate ligament reconstructions are compared. CONCLUSIONS: In the quality assessment several weaknesses in the study design of the RCTs were found. This emphasizes the need for further high-quality studies, especially with long-term follow-up. LEVEL OF EVIDENCE: Level II, systematic review of randomized controlled trials. [ a b c d ]
17	Raynor MC, Pietrobon R, Guller U, Higgins LD, 2005. "Cryotherapy after ACL reconstruction: a meta-analysis." J Knee Surg 18 (2): 123-9 [PubMed] Abstract: Cryotherapy is a common treatment modality after orthopedic surgery procedures. Single institutional randomized clinical trials have evaluated the efficacy of cryotherapy after arthroscopically-assisted anterior cruciate ligament (ACL) reconstruction. Most of these studies were, however, underpowered to detect clinically relevant outcomes differences. This meta-analysis assessed the combined scientific evidence of studies evaluating the effectiveness of cryotherapy after arthroscopically-assisted ACL reconstruction. Electronic databases and bibliographic references of relevant articles were used to identify all relevant randomized clinical trials comparing cryotherapy to a placebo group after ACL reconstruction. Outcomes under investigation were postoperative drainage, range of motion, and pain. Random-effects models were used to combine the findings of the randomized controlled trials. Seven randomized clinical trials were included in the meta-analysis. Postoperative drainage (P=.23) and range of motion (P=.25) were not significantly different between cryotherapy and control group. However, cryotherapy was associated with significantly lower postoperative pain (P=.02). This meta-analysis showed that cryotherapy has a statistically significant benefit in postoperative pain control, while no improvement in postoperative range of motion or drainage was found. As the cryotherapy apparatus is fairly inexpensive, easy to use, has a high level of patient satisfaction, and is rarely associated with adverse events, we believe that cryotherapy is justified in the postoperative management of knee surgery.
18	Melegati G, Tornese D, Bandi M, Volpi P, Schonhuber H, Denti M, 2003. "The role of the rehabilitation brace in restoring knee extension after anterior cruciate ligament reconstruction: a prospective controlled study." Knee Surg Sports Traumatol Arthrosc 11 (5): 322-6 [PubMed] Abstract: To evaluate the effects of a rehabilitation brace locked in extension for the first week on the recovery of full extension after ACL reconstruction we compared two groups of subjects who underwent ACL bone-patellar tendon-bone reconstruction. The brace was unlocked twice a day for assisted physiotherapy. In Group A, 18 male subjects wore a post-operative brace locked from 0 degrees to 90 degrees. In Group B, 18 male subjects wore the same post-op brace locked in full extension for the first week. In both groups the brace was unlocked (0 degrees -120 degrees ) at the beginning of the second postoperative week, and then removed at the beginning of the third week. All the subjects followed the same rigorous, accelerated rehabilitation protocol. Each subject was evaluated pre and post-operatively (at second, fourth and eighth week) with bubble-level heel height difference (HHD) measurements and KT 1000 arthrometric assessment at the fourth postoperative month. Preoperative bubble-level HHD measurements of the two groups were statistically similar (Group A 0.6 cm, Group B 1 cm; not significant, n.s.). At the fourth week (Group A 2.2 cm, Group B 0.6 cm) and eighth week (Group A 1.6 cm, Group B 0.1 cm) follow-ups, bubble-level HHD measurements showed that the extension of the operated knees of Group B was significantly greater than in Group A. KT 1000 arthrometric scores showed no difference between the two groups (Group A 1.8 mm, Group B 1.5; n.s.).
19	Mikkelsen C, Cerulli G, Lorenzini M, Bergstrand G, Werner S, 2003. "Can a post-operative brace in slight hyperextension prevent extension deficit after anterior cruciate ligament reconstruction? A prospective randomised study." Knee Surg Sports Traumatol Arthrosc 11 (5): 318-21 [PubMed] Abstract: It has been our observation that post-operative anterior cruciate ligament (ACL) braces together with the post-operative bandages do not always allow the knee to reach full extension. In ten uninjured knees with known hyperextension, the knees were bandaged in the same way as after an ACL-reconstruction. The knees were then studied radiologically in a Hypex brace set at 0 degrees, -5 degrees and -10 degrees of knee extension. Not a single knee was found to be straight in the brace set at 0 degrees. At -5 degrees most of the knees were straight or in slight hyperextension. It took -10 degrees to get all knees straight or in hyperextension. In a prospective randomised study 44 patients who underwent an arthroscopic ACL-reconstruction with a bone patellar tendon bone graft were randomised to use either a brace set at -5 degrees or a straight brace (0 degrees ) for at least the first three postoperative weeks. Before and three months after surgery range of motion was determined, using a goniometer with long arms, and sagittal knee laxity was measured with a KT-2000 arthrometer at manual max. Pre- and post-operative pain was evaluated with the Visual Analogue Scale (VAS). The same examiner (blindfolded to what type of brace was used) performed all the measurements. At three months, two of the 22 patients with the brace set at -5 degrees and twelve of the 22 patients with the straight brace had a loss of full extension of 2 degrees or more ( p<0.001). No significant differences were found between the groups in terms of knee flexion, sagittal knee laxity or post-operative pain. Although extension deficit after ACL-reconstruction can be prevented also in other ways, a Hypex brace set at -5 degrees seems to be an easy way of ensuring full knee extension.
20	Tyler TF, McHugh MP, Gleim GW, Nicholas SJ, 1998. "The effect of immediate weightbearing after anterior cruciate ligament reconstruction." Clin Orthop Relat Res (357): 141-8 [PubMed] Abstract: Immediate weightbearing has been advocated after anterior cruciate ligament reconstruction and is thought to enhance the return of quadriceps muscle activity and knee extension range of motion without jeopardizing graft integrity. This study examined the effect of immediate weightbearing after anterior cruciate ligament reconstruction on the return of vastus medialis oblique electromyography activity, knee extension range of motion, knee stability, physical examination, Lysholm score, and anterior knee pain. Forty-nine patients (24 men and 25 women) undergoing endoscopic central third patella tendon autograft reconstruction were randomized prospectively into two groups. Group 1 patients underwent immediate weightbearing as tolerated. Group 2 patients were kept nonweightbearing for 2 weeks. All measurements were taken before surgery, 2 weeks after surgery, and between 6 and 14 months (average, 7.3 months) followup. There was no effect of weightbearing on knee extension range of motion or vastus medialis oblique function at followup. In addition, knee stability was not compromised after surgery. Seven of 20 (35%) nonweightbearing patients and only two of 25 (8%) immediate weightbearing patients reported anterior knee pain at followup. Overall, immediate weightbearing did not compromise knee joint stability and resulted in a better outcome with a decreased incidence of anterior knee pain.
21	Gerber JP, Marcus RL, Dibble LE, Greis PE, Burks RT, LaStayo PC, 2009. "Effects of early progressive eccentric exercise on muscle size and function after anterior cruciate ligament reconstruction: a 1-year follow-up study of a randomized clinical trial." Phys Ther 89 (1): 51-9 [PubMed] Abstract: BACKGROUND AND PURPOSE: The authors previously reported that focused eccentric resistance training during the first 15 weeks following anterior cruciate ligament reconstruction (ACL-R) induced greater short-term increases in muscle volume, strength, and measures of function relative to standard rehabilitation. The purpose of this study was to evaluate the effects of early progressive eccentric exercise on muscle volume and function at 1 year after ACL-R. PARTICIPANTS AND METHODS: Forty patients who had undergone an ACL-R were randomly assigned to 1 of 2 groups: a group that received early progressive eccentric exercise (n=20) and a group that received standard rehabilitation (n=20). Seventeen participants in the eccentric exercise group and 15 participants in the standard rehabilitation group completed a 1-year follow-up. Magnetic resonance images of the thighs were acquired 1 year after ACL-R and compared with images acquired 3 weeks after surgery. Likewise, routine knee examinations, self-report assessments, and strength and functional testing were completed 1 year after surgery and compared with previous evaluations. A 2-factor analysis of variance for repeated measures (group x time) was used to analyze the data. RESULTS: Compared with the standard rehabilitation group, improvements in quadriceps femoris and gluteus maximus muscle volume in the involved lower extremity from 3 weeks to 1 year following ACL-R were significantly greater in the eccentric exercise group. Improvements in quadriceps femoris and gluteus maximus muscle volume were 23.3% (SD=14.1%) and 20.6% (SD=12.9%), respectively, in the eccentric exercise group and 13.4% (SD=10.3%) and 11.6% (SD=10.4%), respectively, in the standard rehabilitation group. Improvements in quadriceps femoris muscle strength and hopping distance also were significantly greater in the eccentric exercise group 1 year postsurgery. DISCUSSION AND CONCLUSION: A 12-week focused eccentric resistance training program, implemented 3 weeks after ACL-R, resulted in greater increases in quadriceps femoris and gluteus maximus muscle volume and function compared with standard rehabilitation at 1 year following ACL-R.
22	Øiestad BE, Engebretsen L, Storheim K, Risberg MA, 2009. "Knee osteoarthritis after anterior cruciate ligament injury: a systematic review." Am J Sports Med 37 (7): 1434-43 [PubMed] Abstract: BACKGROUND: This is a systematic review of studies on the prevalence of osteoarthritis in the tibiofemoral joint more than 10 years after an anterior cruciate ligament injury, the radiologic classification methods used, and risk factors for development of knee osteoarthritis. METHODS: A systematic search was performed in PubMed, EMBASE, and AMED. Inclusion criteria were studies involving patients with anterior cruciate ligament injury, either isolated or combined with medial collateral ligament or meniscal injury and either surgically or nonsurgically treated, and a minimum 10-year follow-up with radiologic assessment. Methodological quality was evaluated using a modified version of the Coleman methodology score. RESULTS: Seven prospective and 24 retrospective studies were included. The mean modified Coleman methodology score was 52 of 90. Reported prevalence of knee osteoarthritis for subjects with isolated anterior cruciate ligament injury was between 0% and 13%. For subjects with anterior cruciate ligament and additional meniscal injury, the prevalence varied between 21% and 48%. Seven different radiologic classification systems were used in the studies. Only 3 studies reported reliability results for the radiologic assessments. The most frequently reported risk factor for development of knee osteoarthritis was meniscal injury. CONCLUSION: This systematic review suggests that the prevalence rates of knee osteoarthritis after anterior cruciate ligament reconstruction reported by previous reviews have been too high. The highest rated studies reported low prevalence of knee osteoarthritis for individuals with isolated anterior cruciate ligament injury (0%-13%) and a higher prevalence of knee osteoarthritis for subjects with combined injuries (21%-48%). Overall, the modified Coleman methodology score was low for the included studies. No universal methodological radiologic classification method exists, making comparisons of the studies and stating firm conclusions on the prevalence of knee osteoarthritis more than 10 years after anterior cruciate ligament injury difficult. [ a b ]
23	Brophy RH, Gill CS, Lyman S, Barnes RP, Rodeo SA, Warren RF, 2009. "Effect of anterior cruciate ligament reconstruction and meniscectomy on length of career in National Football League athletes: a case control study." Am J Sports Med 37 (11): 2102-7 [PubMed] Abstract: BACKGROUND: Meniscal and anterior cruciate ligament (ACL) injuries are common in college football athletes. The effect of meniscectomy and/or ACL surgery on the length of an athlete's career in the National Football League (NFL) has not been well examined. HYPOTHESIS: Athletes with a history of meniscectomy or ACL surgery before the NFL combine have a shorter career than matched controls. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A database containing the injury history and career NFL statistics of athletes from 1987-2000 was used to match athletes with a history of meniscectomy and/or ACL surgery, and no other surgery or major injury, to controls without previous surgeries. Athletes were matched by position, year drafted, round drafted, and additional injury history. RESULTS: Fifty-four athletes with a history of meniscectomy, 29 with a history of ACL reconstruction, and 11 with a history of both were identified and matched with controls. Isolated meniscectomy reduced the length of career in years (5.6 vs 7.0; P = .03) and games played (62 vs 85; P = .02). Isolated ACL surgery did not significantly reduce the length of career in years or games played. Comparing the athletes with meniscectomy or ACL reconstruction to athletes with combined ACL reconstruction and meniscectomy, a history of both surgeries, resulted in a shorter career in games started (7.9 vs 35.1; P <.01), games played (41 vs 63; P = .07), and years (4.0 vs 5.8; P = .08) than a history of either surgery alone. CONCLUSION: A history of meniscectomy, but not ACL reconstruction, shortens the expected career of a professional football player. A combination of ACL reconstruction and meniscectomy may be more detrimental to an athlete's durability than either surgery alone. Further research is warranted to better understand how these injuries and surgeries affect an athlete's career and what can be done to improve the long-term outcome after treatment.
24	Busfield BT, Kharrazi FD, Starkey C, Lombardo SJ, Seegmiller J, 2009. "Performance outcomes of anterior cruciate ligament reconstruction in the National Basketball Association." Arthroscopy 25 (8): 825-30 [PubMed] Abstract: PURPOSE: The purpose of this study was to determine the rate of return to play and to quantify the effect on the basketball player's performance after surgical reconstruction of the anterior cruciate ligament (ACL). METHODS: Surgical injuries involving the ACL were queried for a 10-year period (1993-1994 season through 2004-2005 season) from the database maintained by the National Basketball Association (NBA). Standard statistical categories and player efficiency rating (PER), a measure that accounts for positive and negative playing statistics, were calculated to determine the impact of the injury on player performance relative to a matched comparison group. Over the study period, 31 NBA players had 32 ACL reconstructions. Two patients were excluded because of multiple ACL injuries, one was excluded because he never participated in league play, and another was the result of nonathletic activity. RESULTS: Of the 27 players in the study group, 6 (22%) did not return to NBA competition. Of the 21 players (78%) who did return to play, 4 (15%) had an increase in the preinjury PER, 5 (19%) remained within 1 point of the preinjury PER, and the PER decreased by more than 1 point after return to play in 12 (44%). Although decreases occurred in most of the statistical categories for players returning from ACL surgery, the number of games played, field goal percentage, and number of turnovers per game were the only categories with a statistically significant decrease. Players in the comparison group had a statistically significant increase in the PER over their careers, whereas the study group had a marked, though not statistically significant, increase in the PER in the season after reconstruction. CONCLUSIONS: After ACL reconstruction in 27 basketball players, 22% did not return to a sanctioned NBA game. For those returning to play, performance decreased by more than 1 PER point in 44% of the patients, although the changes were not statistically significant relative to the comparison group. LEVEL OF EVIDENCE: Level IV, therapeutic case series.
25	Carey JL, Huffman GR, Parekh SG, Sennett BJ, 2006. "Outcomes of anterior cruciate ligament injuries to running backs and wide receivers in the National Football League." Am J Sports Med 34 (12): 1911-7 [PubMed] Abstract: BACKGROUND: Anterior cruciate ligament injuries are common in professional football players, and their career impact is unclear. PURPOSE: To quantify the affect of anterior cruciate ligament injuries on professional football player performance. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2. METHODS: Anterior cruciate ligament injury data from the National Football League were collected during a 5-year period (1998-2002) for running backs and wide receivers. Recorded variables included player age, experience, position, time to return to competition, and yearly total yards and touchdowns. Power ratings (total yards divided by 10 plus touchdowns multiplied by 6) were calculated for the injury season as well as for the 3 seasons before and after injury. A control group consisted of all running backs and wide receivers without an identified anterior cruciate ligament injury who competed in the 2000 season. RESULTS: Data were analyzed for 31 running backs and wide receivers with 33 anterior cruciate ligament injuries. More than one fifth of players never returned to a National Football League game. Returning players first competed in a game 55.8 +/- 5.4 weeks (mean +/- standard error) after injury. For the 24 anterior cruciate ligament-injured players with a minimum total power rating (sum of all 7 seasons) of 200 points, power rating per game played decreased from 9.9 +/- 1.1 preinjury to 6.5 +/- 0.9 postinjury. This decline in power rating per game played was statistically significant (P = .002) when compared with the change for the 146 control players. CONCLUSION: Nearly four fifths of National Football League running backs and wide receivers who sustain an anterior cruciate ligament injury return to play in a game. On return to competition, player performance of injured players is reduced by one third.
26	Mouzopoulos G, Fotopoulos VC, Tzurbakis M, 2009. "Septic knee arthritis following ACL reconstruction: a systematic review." Knee Surg Sports Traumatol Arthrosc 17 (9): 1033-42 [PubMed] Abstract: Although postoperative septic arthritis is rare after ACL reconstruction, it carries a high morbidity that results in poor clinical outcome. Despite low incidence, it is important to recognize that infection and treat it without delay because of devastating consequences, such as loss of hyaline cartilage and arthrofibrosis, in order to avoid osteoarthritis development and near full range of motion achieved. Herein we discuss the pathogenesis, risk factors, clinical presentation, diagnostic evaluation, treatment protocols and complications of septic knee arthritis after ACL reconstruction.

[1] DeLee, Jesse C., David Drez Jr., and Mark D. Miller, eds. DeLee & Drez's orthopaedic sports medicine principles and practice. 3rd ed. Vol. 2. Philadelphia: Saunders/Elsevier, 2010.

[2] Garrick, J. G. (Ed.). (2004). Orthopaedic Knowledge Update: Sports Medicine (3rd ed.). Rosemont, IL: American Academy of Orthopaedic Surgeons.

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Improved Tendon Radioprotection by Combined Cross-linking and Free Radical Scavenging

Cancellous Bone Properties and Matrix Content of TGF-β2 and IGF-I in Human Tibia: A Pilot Study

Adaptation and Validation of Turkish Version of the Knee Outcome Survey-Activities for Daily Living Scale

Incidence of the Remnant Femoral Attachment of the Ruptured ACL

Springerlink Resources

Fri Jul 30 09:52:01 PDT 2010

Combined reconstruction for posterolateral rotatory instability with anterior cruciate ligament injuries of the knee

Contributory factors to the results of gravity-assisted pivot-shift test for anterior cruciate ligament injury: the significance of muscle torque around the knee

A new ambulatory system for comparative evaluation of the three-dimensional knee kinematics, applied to anterior cruciate ligament injuries

Gravity-assisted pivot-shift test for anterior cruciate ligament injury: a new procedure to detect anterolateral rotatory instability of the knee joint

Untreated acute anterior cruciate ligament tears of the knee: Progression and the influence of associated injuries

Orthopaedic Web Links

Internet resources validated by OrthopaedicWebLinks.com

Fri Jul 30 09:52:02 PDT 2010

Soft Tissue Knee Injuries eMedicine Emergency

Collateral Ligament Pathology Knee eMedicine Orthopedics

Posterior cruciate ligament injuries of the knee Orthopaedia

Anterior cruciate ligament sprain Orthopaedia

Combined knee injuries involving anterior cruciate and medial collateral ligament tears

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