Multiple Ligament Knee Reconstructions

Patients with multiligament knee injuries require a thorough examination (Lachman, posterior-drawer, varus, valgus, and rotational testing). Diagnoses are confirmed with magnetic resonance imaging as well as stress radiographs (posterior, varus, and valgus) when indicated. Multiple systematic reviews have reported that early (<3 weeks after injury) single-stage surgery and early knee motion improves patient-reported outcomes. Anatomic-based reconstructions of the torn primary static stabilizers and repair of the capsular structures and any tendinous avulsions are performed in a single-stage. Open anteromedial or posterolateral incisions are preferentially performed first to identify the torn structures and to prepare the posterolateral corner (PLC) and medial knee reconstruction tunnels. Next, arthroscopy allows preparation of the anterior cruciate ligament (ACL) and double-bundle (DB) posterior cruciate ligament (PCL) tunnels. Careful attention to tunnel trajectory minimizes the risk for convergence. Meniscal tears are preferentially repaired (root and ramp tears are commonly seen in this patient group). Graft passage is performed after all tunnels are reamed. The graft tensioning and fixation sequence is as follows: anterolateral bundle of the PCL to restore the central pivot, posteromedial bundle of the PCL, ACL, PLC (including fibular [lateral] collateral ligament), and posteromedial corner (including medial collateral ligament). Graft integrity and full knee range of motion should be verified before closure. Physical therapy commences on postoperative day 1 with immediate knee motion (flexion from 0°-90°; prone for DB-PCL reconstruction) and quadriceps activation. Patients are nonweightbearing for 6 weeks. Patients with ACL-based reconstructions wear an immobilizer for 6 weeks then transition to a hinged ACL brace. Patients with PCL-based reconstructions transition into a dynamic PCL brace once swelling subsides and wear it routinely for 6 months. Functional testing and stress radiography are performed to validate return to sports.     

How to treat knee ligament injuries?

Indications for conservative treatment of knee ligament injuries can be established for all grade I or II sprains (partial tears), as well as isolated grade III sprains (complete tears) of the posterior cruciate ligament (PCL) and medial collateral ligament (MCL). These injuries should be treated with immediate mobilization. Only in isolated partial anterior cruciate ligament (ACL) tears without a positive pivot shift phenomenon is conservative treatment justified. However, many of these injuries may require operative reconstruction later. In complete ACL tears the surgical treatment consists of primary reconstruction or augmented primary repair. Today, the middle third of the patella tendon with the bone blocks is regarded as the "gold standard" for augmented repairs and late reconstructions. For the present, there is no place for synthetic prostheses in the treatment of an acute ACL rupture. Allograft replacement of the ACL must now be considered an experimental procedure. In the reconstruction of the PCL the above mentioned patella tendon graft is also preferable. Lateral collateral ligament (LCL) tears, especially if they are combined with ruptures of posterolateral ligament complex, should be repaired immediately after the injury. In these injuries late reconstructions are difficult and the results are poor. Conservative treatment of partial tears and postoperative treatment of reconstructed ligaments is twofold: on the one hand, the healing tissue should be protected and on the other hand, atrophy and wasting of uninjured tissue should be avoided. Overload and stretching of the injured ligaments should be eliminated with the aid of a suitable knee brace, but early range of motion exercises of the knee are allowed immediately.(ABSTRACT TRUNCATED AT 250 WORDS)     

Arthroscopically assisted combined anterior and posterior cruciate ligament reconstruction

This article presents the minimum 2-year results (range, 24 to 48 months) of 20 arthroscopically assisted combined anterior cruciate ligament/posterior cruciate ligament (ACL/PCL) reconstructions, evaluated preoperatively and postoperatively using the Tegner, Lysholm, and Hospital for Special Surgery knee ligament rating scales, and the KT 1000 knee ligament arthrometer (Medmetric Corp, San Diego, CA). There were 16 men or boys, 4 women or girls; 9 right, 11 left; 10 acute, and 10 chronic knee injuries. Ligament injuries included 1 ACL/PCL tear, 2 ACL/PCL/medial collateral ligament (MCL)/posterior lateral corner tears, 7 ACL/PCL/MCL tears, and 10 ACL/PCL/posterior lateral corner tears. ACLs were reconstructed using autograft or allograft patellar tendons. PCLs were reconstructed using allograft Achilles tendon, or autograft patellar tendon. MCL tears were successfully treated with bracing. Posterior lateral instability was successfully treated with long head of the biceps femoris tendon tenodesis. Teguer, Lysholm, and Hospital for Special Surgery knee ligament rating scales significantly improved preoperatively to postoperatively (P = .0001). Corrected anterior KT 1000 measurements improved from preoperative to postoperative status (P = .0078).     

Acute hemarthrosis of the knee: indications for diagnostic arthroscopy

The objective of this study was to define the role of early diagnostic knee arthroscopy for patients with an acute knee injury and hemarthrosis. Forty-five patients with an acute knee injury followed by a posttraumatic hemarthrosis during a 1-year period were prospectively reviewed. All patients were evaluated preoperatively followed by examination under anesthesia and arthroscopy of the knee. The majority of patients, 32 (71%), had an anterior cruciate ligament tear. Meniscal tears occurred in 21 patients (47%). Meniscal tears requiring surgery occurred in only 10 of 25 meniscal tears (40%). Seven patients (16%) had medial collateral ligament and/or posteromedial capsular sprain. Eight patients (18%) had an osteochondral fracture or patellar dislocation associated with an osteochondral fracture. The majority of knees with a torn meniscus or osteochondral fracture had an anterior cruciate ligament tear. Clinically, 18 of 21 knees (86%) with an acute complete anterior cruciate ligament tear were diagnosed preoperatively with the Lachman test. The Lachman test conducted with patients under anesthesia was positive for 19 of 21 knees (90%) with an acute complete anterior cruciate ligament tear. The preoperative examination correctly identified six of seven knees (86%) with a medial collateral ligament sprain. The preoperative Lachman test was positive in only two of five knees (40%) with a partial anterior cruciate ligament tear. The Lachman test with patients under anesthesia was positive for four of five knees (80%) with an acute partial anterior cruciate ligament tear. Preoperative examination yielded the correct diagnosis in only 9 of 21 knees (43%) with a meniscal tear and 1 of 6 knees (17%) with an osteochondral fracture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Post-traumatic hemarthrosis of the knee joint--an indication for arthroscopy

Diagnostic arthroscopy including the use of a probe should be performed if the cause for a haemarthrosis of the knee cannot be established by radiological means. The clinical examination of the recently injured knee must be considered to be unreliable due to pain. In approximately one-third of knee injuries an incorrect or incomplete diagnosis is made. Even if ligamentous injuries can be established, arthroscopy is mandatory, because this is the only sure way in which acute and degenerative meniscal or cartilaginous lesions can be diagnosed. Arthroscopy should be performed under general or spinal anaesthesia to allow the use of a tourniquet and the immediate repair of ligaments if deemed necessary. The experienced arthroscopist needs only a few minutes to obtain information that could influence the approach to the injury and its longterm prognosis. In a series of 1238 arthroscopies 252 (20.3%) were done for haemarthrosis of unknown origin. In 68% of these cases diagnosis could only have been established by arthroscopy. In this series of 252 cases 23% had an isolated complete anterior cruciate ligament (ACL) injury, 28% had anterior-medical instability, 8% had partial ACL lesions, 5% posterior cruciate ligament injuries, 15% medial collateral ligament injuries, 11% had only synovial tears or contusions. 5% of cases had chronic ACL instability, 4% had osteochondral fragments which could not be diagnosed radiologically. A recent traumatic patellar dislocation with a tear of the retinaculum was found in 1.6% of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of knee instability in acute ligamentous injuries

The stability on clinical examination (CE) and examination under anaesthesia (EUA) was evaluated in 350 consecutive acute knee injuries. Valgus instability in knees with a medial collateral tear was observed on CE in 62 and on EUA in 67 cases (p less than 0.05). The anterior drawer sign was positive in 55 patients on CE and in 110 patients on EUA (p less than 0.0001), the corresponding figures for the Lachman test were 66 and 126 respectively (p less than 0.0001). The pivot shift-test was positive in 13 cases on CE and in 87 under anaesthesia (p less than 0.0001). Fresh total tears of the anterior cruciate ligament (confirmed at arthrotomy, n = 79) were detected by the Lachman test in 48 per cent on CE and in 96 per cent on EUA. Of the nine fresh, total tears of the posterior cruciate ligament three were disclosed by the posterior drawer test on CE and all nine on EUA. Anteromedial rotatory instability was observed on CE in 10 patients and on EUA in 47 (p less than 0.0001). In these patients 41 medial collateral tears, 23 posteromedial capsular tears, 21 medial meniscus and 40 anterior cruciate lesions were found. On CE only one anterolateral rotatory instability was found, whereas EUA disclosed 9 cases. Posteromedial rotatory instability was not confirmed on CE, though on EUA four cases were found. CE and EUA detected 2 and 3 posterolateral instabilities respectively. In conclusion, the use of EUA with an adequate mode of stability evaluation in acute knee injuries is strongly advocated. Clinical examination is considered highly unreliable with many false negative findings.     

Primary knee ligament repair--revisited

There were 4710 knee sprains resulting from skiing in the four Aspen ski areas between 1976 and 1979. Twenty percent of the patients (942) had complete tears. Of these, 302 elected to remain in Aspen for treatment. All were treated by primary ligament repair without augmentation. These cases were evaluated an average of 42 months after injury. Patients with isolated tears of the medial collateral ligament were found to be doing well; virtually all of them had returned to preinjury activity levels. Thirty-six percent of the isolated anterior cruciate repairs were rated failures, and 43% of the combination ACL-MCL injuries had failed because of anterior cruciate deficiency. Twenty-nine percent of the ACL and ACL-MCL injuries had meniscal tears. Cases that included meniscectomy had a failure rate twice as great as those in which the meniscus was preserved. The results following repair of anterior cruciate tears were not acceptable, and augmentation was indicated. Primary repair of medial collateral ligament tears produced excellent results. Meniscal tears were frequent in association with ligament disruption. Ligament repairs were less satisfactory when meniscectomy was performed at the time of the repair.     

Isolierte und kombinierte Kniebandverletzungen

Complex knee ligament injuries are characterized by simultaneous rupture of the anterior cruciate ligament (ACL) and/or the posterior cruciate ligament (PCL) and at least one collateral ligament. Isolated injury to the medial collateral ligament (MCL) and PCL have a high healing capacity and can be treated conservatively in many cases. Ruptures of the MCL can also be treated conservatively in complex injuries if the cruciate ligaments are reconstructed. Ruptures of the lateral structures usually need surgical reconstruction. Indications for acute surgical repair include meniscus dislocation, entrapment of collateral ligament portions in the joint, knee dislocation with severe knee instability, and displaced bony avulsions. The anatomy of the knee ligaments must be carefully respected in surgical reconstruction. Acute repair of collateral ligament injuries is possible only in the first 2 weeks after trauma. Acute arthroscopy is indicated only in combination with reconstructive surgery.     

Medial and lateral segond fractures in a skeletally immature patient: a radiographic marker for the multiply injured knee

Marginal fractures of the medial tibial plateau have been reported in the literature as a secondary type of Segond fracture. Some reports described this entity in the setting of combined injuries such as root avulsions of the medial meniscus, complete disruption of the posterior cruciate ligament (PCL), partial tear of the anterior cruciate ligament (ACL), and tears of the medial meniscus and medial collateral ligament. It has been postulated that medial marginal fractures are secondary to compression of the medial aspect of the femoral condyle and tibial plateau with a corresponding posterolateral corner injury. However, this mechanism of injury may not always be as straightforward.This article presents a case of an alternate injury pattern in a skeletally immature patient. A 16-year-old boy sustained a varus force and twisting injury to his knee, resulting in radiographic evidence of multiple avulsion fractures of the knee, including a fibular epiphyseal avulsion fracture and medial and lateral Segond fractures. Usually, the avulsion fractures serve as markers for significant ligamentous injuries in adult patients, but our patient had minimal injury to the PCL, ACL, and posterolateral corner. Further physical examination and imaging studies revealed an anterior horn root avulsion, meniscocapsular separation, and anterior cortical rim fracture. A combination of imaging modalities helped us further characterize the injury pattern to devise the optimal surgical plan, especially the fixation of the anterior cortical fracture of the tibia.     

The outcome of nonoperatively treated complete tears of the anterior cruciate ligament in active young adults

The results of nonoperative treatment of 72 patients with complete anterior cruciate ligament (ACL) tears, documented by examination under anesthesia and arthroscopy, were evaluated. All patients had an acute injury with hemarthrosis in a previously normal knee. Patients having meniscal repair were excluded as were those with collateral or posterior cruciate ligament tears or associated fractures. Treatment in all cases consisted of a standard protocol of early rehabilitation and bracing. A detailed rating of symptoms and function was performed at an average of 38 months postinjury (range, eight to 84 months). Overall results were 11% excellent, 20% good, 15% fair, and 54% poor. Thirty-five percent had ACL reconstruction during the follow-up period. Results indicate that young adults who return to a vocation requiring strenuous physical activity frequently can expect unsatisfactory results after nonoperative treatment of an acute complete tear of the ACL.     

Management of the dislocated/multipleligament injured knee

The multiple ligament injured knee is a complex problem in orthopaedic surgery. Most dislocated knees involve tears of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and at least one collateral ligament complex. Careful assessment of the vascular status of the extremity is essential because of the possibility of arterial and/or venous compromise. These complex injuries require a systematic approach to evaluation and treatment. Physical examination and imaging studies enable the surgeon to make a correct diagnosis and to formulate a treatment plan. Arthroscopically assisted combined ACL/PCL reconstruction is a reproducible procedure. Knee stability is improved postoperatively when evaluated using knee ligament rating scales, arthrometer testing, and stress radiographic analysis. Acute medial cruciate ligament tears, when combined with ACL/PCL tears, may, in certain cases, be treated with bracing. Posterolateral corner injuries combined with ACL/PCL tears are best treated with primary repair as indicated combined with reconstruction using a post of strong autograft (split biceps tendon, biceps tendon, semitendinosus) or allograft (Achilles tendon, bone patellar tendon bone) tissue. Surgical timing depends on the ligaments injured, the vascular status of the extremity, reduction stability, and the overall health of the patient. We prefer the use of allograft tissue for reconstruction in these cases because of the strength of these large grafts and the absence of donor site morbidity.     

Complex instability of the anterior knee

Complex knee instability involves the anterior cruciate ligament (ACL) and one or more major stabilizers of the knee [medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL)]. The medial side has a high healing potential and does not need operative treatment in most cases if ACL reconstruction is performed. Reconstruction of the medial ligament complex is indicated in gross instability of the medial meniscus fixation, dislocation of the MCL into the joint, and large dislocated bony avulsions. Injuries on the lateral side do not heal spontaneously and require acute operative treatment (first 2 weeks). Frank knee dislocations and gross multiligament injuries should be reduced acutely, and the integrity of the vascular structures must be examined closely. In a European multicenter study, operative treatment with reconstruction of both cruciate ligaments and functional rehabilitation gave better results than conservative treatment with immobilization of the joint.     

全关节镜下膝关节后外复合体重建

目的 介绍全关节镜下腘肌腱重建、腘肌腱联合腘腓韧带重建或膝关节后外复合体(posterolateral corner,PLC)解剖重建的手术技术,探讨全关节镜下PLC重建治疗膝关节后外不稳定的效果.方法 2008年8月至2010年4月,共完成全关节镜下后十字韧带(posterior cruciate ligament,PCL)+PLC重建手术34例.患者在接受手术时平均年龄34.1岁(15～52岁);男32例,女2例;从受伤到手术平均10.7个月.所有病例均为陈旧性损伤,且均为复合韧带损伤.所有PCL损伤的病例都存在PLC损伤.合并前十字韧带损伤6例(17.6%),合并前十字韧带、内侧副韧带损伤2例(5.9%),合并内侧副韧带损伤5例(14.7%).对膝关节PLC损伤进行分型,采用不同的重建技术进行治疗.对于A型旋转不稳定,采用全关节镜下腘肌腱重建、腘肌腱联合腘腓韧带重建;对于C型后外不稳定,采用全关节镜下PLC解剖重建.结果 14例患者获得随访并进行二次关节镜检查,平均随访18.5个月(13～25个月).终末随访包括:膝关节查体、KT-1000测量、膝关节应力像和胫骨外旋稳定性.使用膝关节应力像测量胫骨后移程度,胫骨后移由术前平均15.56mm减少为术后5.16mm,手术前后差异有统计学意义.使用屈膝30°位胫骨外旋试验评估膝关节后外旋转不稳定.对比患侧与健侧胫骨外旋的差值,由术前平均14.92°减小为术后-0.22°,手术前后差异有统计学意义.术后患者平均屈曲受限4.23°,无伸膝受限.结论 对于膝关节PLC损伤导致的不稳定,采用全关节镜下PLC重建的手术技术,能够有效恢复膝关节后外旋转不稳定.这种手术技术能够与PCL重建联合应用.

Abstract：

Objectiye To introduce the surgical technique of arthroscopy assisted anatomical posterolateral corner (PLC) reconstruction,including popliteal ligament,popliteofibular ligament and lateral collateral ligament,and evaluate the results of this technique.Methods From August 2008 to April 2010,34arthroscopic posterior cruciate ligament (PCL) and PLC reconstruction surgeries were performed.The average age of the patients was 34.1 (15-52) years.There were 32 males and 2 females.The average time period from injury to surgery was 10.7 months.All patients were chronic injuries and combined ligament injuries,including PCL and PLC injuries.Some cases had other ligament injury,including 6 patients of anterior cruciate ligament (ACL) injury (17.6%),2 of ACL combined medial cruciate ligament (MCL) injuries (5.9%),and 5 of MCL injuries (14.7%).According to Fanellis classification,for type A posterolateral rotation instability,we performed arthroscopic popliteal ligament reconstruction or popliteal ligament combined popliteofibular ligament reconstruction.For type C posterolateral instability,we performed arthroscopic PLC anatomical reconstruction.Results During the follow-up period,14 patients had undergone a second look arthroscopic examination and removal of hardware.The average follow-up time was 18.5 months (13-25 months).At the final follow-up,physical examination,stability evaluation with KT-1000 and Telos stress view,and dial test were performed.The posterior displacement of the knee had decreased from 15.56 mm preoperatively to 5.16mm postoperatively.The external rotation instability had decreased from 14.92° preoperatively to -0.22°postoperatively.The average limitation of knee flexion was 4.23° and no knee extension was limited.Conclusion With the surgical technique of arthroscopy assisted anatomical PLC reconstruction,we can restore the external rotation stability of knee.This technique can be performed combine with PCL reconstruction.     

Early ACL reconstruction in combined ACL-MCL injuries

This study reports 18 patients with 19 combined ligament injuries with complete anterior cruciate ligament (ACL) tear and a minimum grade II medial collateral ligament (MCL) tear who underwent early reconstruction of the ACL and nonoperative treatment of the MCL. Inclusion criteria included ACL reconstruction performed within 3 weeks of initial injury, no history of antecedent injury to the ipsilateral knee, and 2-year follow-up data. Associated injuries were noted in 11 patients including 6 isolated lateral meniscal tears, 1 isolated medial meniscal tear, 5 combined meniscal tears, 1 chondral injury, and 1 patellar fracture. Subjective minimum 2-year follow-up yielded a mean Lysholm score of 94.5 and a mean Tegner activity score of 8.4. Serial clinical examinations demonstrated good functional outcomes, range of motion, and strength. No patient experienced ACL graft failure or valgus instability or required subsequent surgery for chondral or meniscal damage. One patient required a second surgery for arthrofibrosis. Clinical and functional outcomes in this study were good with low motion complication rates. Based on our data, early surgical reconstruction of the ACL and nonoperative treatment of the MCL in combined injuries is acceptable and results in excellent clinical and functional outcomes.     

What is the terrible triad?

In 1936 Campbell asserted that "impairment of the anterior crucial and mesial ligaments is associated with injuries of the internal cartilage." O'Donoghue in 1950 called attention to "that unhappy triad (1) rupture of the medial collateral ligament, (2) damage to the medial meniscus, and (3) rupture of the anterior cruciate ligament" and recommended early surgical intervention. In 1955 he reported 33 cases with both medial collateral (MCL) and anterior cruciate ligament (ACL) tears, but there were only three lateral meniscus tears reported. Based on a recent report by Shelbourne and Nitz that questions the validity of this unhappy triad, a review of all arthroscopically confirmed acute injuries of second degree or worse to the ACL and MCL was undertaken. Of a total of 52 knees reviewed, 50 knees had third-degree ACL tears and two had second-degree ACL tears. One of the second-degree tears was associated with a second-degree MCL and one with a third-degree ACL tear. Neither had an associated meniscus tear. Forty-five third-degree ACL tears were associated with third-degree MCL tears (group 1) and five with second-degree MCL tears (group 2). Eighty percent (36 knees) of group 1 had lateral meniscus tears. Only 29% of group 1 (13 knees) had associated medial meniscus tears. None of these medial meniscus tears was isolated. Eighty percent (four knees) of group 2 had lateral meniscus tears with only one associated medial meniscus tear. Again, there were no medial meniscus tears in the absence of a lateral meniscus tear. We did not find the combination of injury originally described as the unhappy triad.     

Ruptur des vorderen Kreuzbands

Rupture of the anterior cruciate ligament (ACL) is the most common ligamentous knee injury. The knee is stabilized by the cruciate ligaments and the collateral ligaments. The ACL originates from the inner surface of the lateral condyle of the femur, runs in an anterior medial direction and inserts at the tibial plateau in the intercondyle area. The most common injury is an indirect knee trauma, typically a joint torsion in sports. Patients often describe a snapping noise followed by hemarthrosis. Concomitant injuries are lesions of the medial collateral ligament, the medial meniscus (unhappy triad) and chondral fractures. The age peak is between 15 and 30 years with a higher incidence in females. The cardinal symptom of the ACL rupture is the giving way phenomenon. The clinical diagnosis is provided by a positive Lachman test, a positive pivot shift test and the anterior drawer test. Fractures can be excluded by X-ray examination. Magnetic resonance imaging (MRI) allows the evaluation of the internal knee structures. ACL repair is carried out by arthroscopically assisted bone-tendon-bone or semitendinosus grafting techniques. Early rehabilitation is important for a good functional outcome.     

Acute traumatic knee effusions in children and adolescents

A prospective analysis was completed during a 6-month period to identify all patients, age 18 years or younger, who presented for evaluation of their knee effusion. There were 44 injured knees in 44 patients. There were a total of 55 diagnoses: 16 (29%) anterior cruciate ligament (ACL) injuries, 16 (29%) meniscal tears, 14 (25%) patellofemoral subluxations or dislocations, 3 (5%) medial collateral ligament sprains, 2 (4%) patellar osteochondral fractures, 2 (4%) retinacular injuries, 1 (2%) posterior cruciate ligament rupture, and 1 (2%) tibial eminence fracture. Girls had 11 of the 14 patellofemoral injuries; 58% of the girls had effusions secondary to patellofemoral pathology compared with 12% of the boys. Boys had 10 of the 16 meniscal tears and 13 of the 16 ACL tears. Fifty-two percent of boys had an injury to the ACL and 44% had an injury to a meniscus. In contrast, 16% of girls had an ACL injury and 32% had meniscal tears. ACL injuries, meniscal tears, and patellofemoral pathology accounted for 87% (48/55) of the diagnoses. Girls were more likely to have patellofemoral pathology; boys were more likely to have ACL and meniscal tears.     

Healing and repair of ligament injuries in the knee

Although methods of treating ligamentous injuries have continually improved, many questions remain about enhancing the rate, quality, and completeness of ligament healing. It is known that the ability of a torn ligament to heal depends on a variety of factors, including anatomic location, presence of associated injuries, and selected treatment modality. A grade III injury of the medial collateral ligament (MCL) of the knee usually heals spontaneously. Surgical repair followed by immobilization of an isolated MCL tear does not enhance the healing process. In contrast, tears of the anterior cruciate ligament (ACL) and the posterior cruciate ligament often require surgical reconstruction. The MCL component of a combined ACL-MCL injury has a worse prognosis than an isolated MCL injury. The results of animal studies suggest that nonoperative treatment of an MCL injury is effective if combined with operative reconstruction of the ACL. Experimentation using animal models has helped to define the effects of ligament location, associated injuries, intrinsic factors, surgical repair, reconstruction, and exercise on ligament healing. New techniques utilizing growth factors and cell and gene therapies may offer the potential to enhance the rate and quality of healing of ligaments of the knee, as well as other ligaments in the body.     

Objective anterior cruciate ligament testing

We examined subjects with the Stryker knee laxity tester as part of the clinical examination to determine its usefulness in evaluating the anterior cruciate ligament. We measured 123 athletes with no history of knee injury, as well as 30 patients with ACL injury proven by arthroscopy, and 11 injured patients with intact ACL at arthroscopy. We recorded anterior and posterior tibial displacement at 20 degrees of knee flexion and 20 lbs force in each direction. Anterior laxity and side to side difference correlated with ACL injury; posterior and total AP laxity did not. In normal subjects, mean anterior laxity was 2.5 mm. Only 8% of normal knees had anterior laxity of 5 mm or more. Ten percent of normal subjects had a side to side difference of 2 mm or more. In ACL tears, mean laxity was 8.1 mm, with 94% measuring 5 mm or more. Of the subjects, 89% with unilateral ACL injury had an increase of 2 mm or more on the injured side. Ten of ten acute ACL tears were detected by these criteria, with no false positives. In injured knees with intact ACL, measurements did not differ significantly from normal. We found the objective knee laxity measurement to be a useful complement to clinical knee examination.