Medial and lateral collateral injuries: prognosis and treatment

Acute Knee Injuries in Children and Adolescents: A Review

IMPORTANCE

Knee injuries in children and adolescents are exceedingly common. When an active youth presents complaining of knee pain, the treating pediatrician should be comfortable with forming a working differential diagnosis and should be able to manage many such injuries or recognize when it is necessary to make an appropriate referral.

OBSERVATIONS

Knee injuries typically present after acute trauma. Appreciating the likely etiologies pertaining to a particular case is best achieved with a thorough history and physical examination. This review discusses the etiologies of acute injuries including fractures that are unique to skeletally immature individuals, patellar dislocations, ligamentous injuries, and meniscal tears. Imaging findings and management of these conditions are also reviewed.

CONCLUSIONS AND RELEVANCE

This review summarizes the more common acute knee injuries seen in active children and adolescents. Given how frequently such conditions present, this overview of diagnosis and management will provide a useful resource for the nonspecialist.

Superficial Medial Collateral Ligament of the Knee: Anatomic Augmentation With Semitendinosus and Gracilis Tendon Autografts

The superficial medial collateral ligament (sMCL) and associated knee structures are the most commonly injured structures of the knee. Most isolated sMCL tears are treated nonoperatively. Several studies have described different algorithms for treatment of sMCL lesions, as well as different types of techniques, both in the acute and in chronic settings. The purpose of this article was to detail our anatomic sMCL augmentation technique using semitendinosus and gracilis tendon autografts.

Ligamentous injuries of the knee: anterior cruciate, medial collateral, posterior cruciate, and posterolateral corner injuries

This article discusses athletic injuries of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and posterolateral corner. Best evidence to date validates that conservative management of ACL ruptures is a reasonable strategy. Current data also seem to advocate nonoperative management of PCL injuries. All isolated MCL injuries, regardless of grade, are usually treated with a brief period of immobilization and symptomatic management. Although the surgical literature often advocates surgical treatment of posterolateral corner injuries, there have been no randomized trials substantiating that these injuries are best treated surgically.

The management of injuries to the medial side of the knee

Injuries to the medial side of the knee are the most common knee ligament injuries. The majority of injuries occur in young athletes during sporting events, with the usual mechanism involving a valgus contact, tibial external rotation, or a combined valgus and external rotation force delivered to the knee. Although most complete grade III medial knee injuries heal, some do not, which can lead to continued instability. For these patients, a thorough understanding of the presenting history and a physical examination are important because these injuries can often be confused with posterolateral corner injuries. The main anatomic structures of the medial side of the knee are the superficial medial collateral ligament, deep medial collateral ligament, and posterior oblique ligament. In addition, accurately locating 3 bony prominences over the medial aspect of the knee-the adductor tubercle, gastrocnemius tubercle, and medial epicondyle-is important to conduct a proper physical examination and for surgical repairs and reconstructions. Clinical diagnosis of medial knee injuries is primarily performed via the application of a valgus stress in full extension and at 30° of knee flexion. In addition, an examination of the amount of anteromedial tibial rotation is performed at 90° of flexion, while the dial test, performed at 30° and 90° of flexion, is important because it evaluates for rotational abnormalities. Valgus stress radiographs are useful to objectively determine the amount of medial compartment gapping and to discern whether there is medial or lateral compartment gapping when a medial or posterolateral corner knee injury cannot be differentiated, especially with a chronic injury. The majority of acute grade III medial knee injuries will heal after a nonoperative rehabilitation program. In most instances when there is a knee dislocation or multiligament injury, a primary repair with sutures may be indicated. In severe midsubstance injuries or chronic medial knee injuries, an anatomic medial knee reconstruction with grafts may be indicated. Rehabilitation principles for acute medial knee injuries involve controlling edema, regaining range of motion, and avoiding any significant stress on the healing ligaments. A well-guided rehabilitation program can result in excellent functional outcomes in the majority of patients.

Injuries to the medial collateral ligament and associated medial structures of the knee

*The superficial medial collateral ligament and other medial knee stabilizers-i.e., the deep medial collateral ligament and the posterior oblique ligament-are the most commonly injured ligamentous structures of the knee. *The main structures of the medial aspect of the knee are the proximal and distal divisions of the superficial medial collateral ligament, the meniscofemoral and meniscotibial divisions of the deep medial collateral ligament, and the posterior oblique ligament. *Physical examination is the initial method of choice for the diagnosis of medial knee injuries through the application of a valgus load both at full knee extension and between 20 degrees and 30 degrees of knee flexion. *Because nonoperative treatment has a favorable outcome, there is a consensus that it should be the first step in the management of acute isolated grade-III injuries of the medial collateral ligament or such injuries combined with an anterior cruciate ligament tear. *If operative treatment is required, an anatomic repair or reconstruction is recommended.

Correlation of valgus stress radiographs with medial knee ligament injuries: an in vitro biomechanical study

BACKGROUND

The amount of medial compartment opening for medial knee injuries determined by valgus stress radiography has not been well documented. The purpose of this study was to develop clinical guidelines for diagnosing medial knee injuries using valgus stress radiography.

HYPOTHESIS

Measurements of medial compartment gapping can accurately differentiate between normal and injured medial structure knees on valgus stress radiographs.

STUDY DESIGN

Controlled laboratory study.

METHODS

Valgus stress radiographs were obtained on 18 adult lower extremities using 10-N.m and clinician-applied valgus loads at 0 degrees and 20 degrees of flexion to intact knees and after sequential sectioning of the superficial medial collateral ligament proximally and distally, the meniscofemoral and meniscotibial portions of the deep medial collateral ligament, the posterior oblique ligament, and the cruciate ligaments. Three independent observers of different experience levels measured all of the radiographs during 2 separate occasions to determine intraobserver repeatability and interobserver reproducibility.

RESULTS

Compared with the intact knee, significant medial joint gapping increases of 1.7 mm and 3.2 mm were produced at 0 degrees and 20 degrees of flexion, respectively, by a clinician-applied load on an isolated grade III superficial medial collateral ligament simulated injury. A complete medial knee injury yielded gapping increases of 6.5 mm and 9.8 mm at 0 degrees and 20 degrees , respectively, for a clinician-applied load. Intraobserver repeatability and interobserver reproducibility intraclass correlation coefficients were .99 and .98, respectively.

CONCLUSION

Valgus stress radiographs accurately and reliably measure medial compartment gapping but cannot definitively differentiate between meniscofemoral- and meniscotibial-based injuries. A grade III medial collateral ligament injury should be suspected with greater than 3.2 mm of medial compartment gapping compared to the contralateral knee at 20 degrees of flexion, and this injury will also result in gapping in full extension. Clinical Significance Valgus stress radiographs provide objective and reproducible measurements of medial compartment gapping, which should prove useful for definitive diagnosis, management, and postoperative follow-up of patients with medial knee injuries.

The reproducibility and repeatability of varus stress radiographs in the assessment of isolated fibular collateral ligament and grade-III posterolateral knee injuries. An in vitro biomechanical study

BACKGROUND

Objective measures to quantitate the amount of lateral compartment opening for patients with lateral and posterolateral knee injuries have not been well documented. The purpose of the present study was to measure lateral compartment opening secondary to applied varus stresses following posterolateral corner structure sectioning and to develop radiographic guidelines to quantify the amount of lateral compartment gapping seen with these injuries.

METHODS

Ten nonpaired fresh-frozen cadaver lower extremities were used. Two varus loads, a 12-Nm moment and a clinician-applied varus stress, were applied to the intact knees and after sequential sectioning of the fibular collateral ligament, popliteus tendon, popliteofibular ligament, and anterior and posterior cruciate ligaments to simulate degrees of posterolateral knee and associated combined cruciate ligament injuries. The shortest distance between the most distal subchondral bone surface of the lateral femoral condyle and the corresponding lateral tibial plateau was measured to quantify lateral compartment opening and was analyzed on digital radiographs. Three observers were used to determine interobserver reproducibility and intraobserver repeatability.

RESULTS

In the intact knee, the mean lateral compartment gapping due to a 12-Nm moment and a clinician-applied varus stress was 8.9 and 9.7 mm, respectively. Lateral gapping significantly increased by 2.1 and 2.7 mm in association with sectioning of the fibular collateral ligament and by 3.4 and 4.0 mm in knees with a simulated posterolateral corner injury for each respective load-application technique (p < 0.0001 for all comparisons). Intraobserver repeatability was high, with all observers independently obtaining an intraclass correlation coefficient of 0.99, whereas the analysis of interobserver reproducibility demonstrated an intraclass correlation coefficient of 0.97.

CONCLUSIONS

Measurements with use of current clinical digital imaging systems can be used to quantify the amount of lateral compartment knee opening. Clinicians should suspect an isolated fibular collateral ligament injury if opening on clinician-applied varus stress radiographs increases by approximately 2.7 mm and a grade-III posterolateral corner injury if values increase by approximately 4.0 mm.

CLINICAL RELEVANCE

Varus stress radiographs appear to provide an objective and reproducible measure of lateral compartment gapping that should prove useful for the diagnosis, management, and postoperative follow-up of patients with fibular collateral ligament and posterolateral knee injuries.