High-energy knee dislocation without anterior cruciate ligament disruption in a skeletally immature adolescent

Examining the Schenck KD I Classification in Patients With Documented Tibiofemoral Knee Dislocations: A Multicenter Retrospective Case Series

Background

Acute tibiofemoral knee dislocations (KDs) with a single cruciate ligament remaining intact are rare and can be classified as Schenck KD I. The inclusion of multiligament knee injuries (MLKIs) has contributed to a recent surge in Schenck KD I prevalence and has convoluted the original definition of the classification.

Purpose

To (1) report on a series of true Schenck KD I injuries with radiologically confirmed tibiofemoral dislocation and (2) introduce suffix modifications to further subclassify these injuries based on the reported cases.

Study Design

Case series; Level of evidence, 4.

Methods

A retrospective chart review identified all Schenck KD I MLKIs at 2 separate institutions between January 2001 and June 2022. Single-cruciate tears were included if a concomitant complete disruption of a collateral injury was present or injuries to the posterolateral corner, posteromedial corner, or extensor mechanism. All knee radiographs and magnetic resonance imaging scans were retrospectively reviewed by 2 board-certified orthopaedic sports medicine fellowship-trained surgeons. Only documented cases consistent with a complete tibiofemoral dislocation were included.

Results

Of the 227 MLKIs, 63 (27.8%) were classified as KD I, and 12 (19.0%) of the 63 KD I injuries had a radiologically confirmed tibiofemoral dislocation. These 12 injuries were subclassified based on the following proposed suffix modifications: KD I-DA (anterior cruciate ligament [ACL] only; n = 3), KD I-DAM (ACL + medial collateral ligament [MCL]; n = 3), KD I-DPM (posterior cruciate ligament [PCL] + MCL; n = 2), KD I-DAL (ACL + lateral collateral ligament [LCL]; n = 1), and KD I-DPL (PCL + LCL; n = 3).

Conclusion

The Schenck classification system should only be used to describe dislocations with bicruciate injuries or with single-cruciate injuries that have clinical and/or radiological evidence of tibiofemoral dislocation. Based on the presented cases, the authors recommend the suffix modifications for subclassifying Schenck KD I injuries with the goal of improving communication, surgical management, and the design of future outcome studies.

Evaluation and Management of Knee Dislocation in the Emergency Department

BACKGROUND

Knee dislocations are a potentially limb-threatening injury, and it is essential that emergency medicine clinicians are aware of them.

OBJECTIVE

This article provides a review of the diagnosis and management of knee dislocation for the emergency provider.

DISCUSSION

Knee dislocations are uncommon injuries with the potential for significant morbidity. A thorough history and examination are important, because 50% of dislocations may have reduced before arrival to the emergency department. Knee dislocations should be quickly reduced in the emergency department setting. The presence of equal pulses does not exclude vascular injury, and all patients should undergo serial vascular examinations and evaluation with ankle-brachial indices. Those with abnormal ankle-brachial indices should receive computed tomographic angiography. Radiographs are important to identify any fractures, while magnetic resonance imaging may be deferred until after admission.

CONCLUSION

Knee dislocation is a potentially dangerous medical condition requiring rapid diagnosis and management. It is essential for emergency clinicians to know how to diagnose and treat this disorder.

Multiligament Knee Injuries in Older Adolescents: A 2-Year Minimum Follow-up Study

Background:

Multiligament knee injuries cause significant functional impairment. Adults undergoing anatomic reconstruction of multiligament knee injuries have excellent outcomes postoperatively. However, less is known about the outcomes in adolescent patients following multiligament reconstruction.

Purpose/Hypothesis:

We aimed to assess patient outcomes and failure rates following unstaged multiligament reconstruction in an adolescent population at a minimum 2-year follow-up. We hypothesized that outcomes of multiligament reconstruction in these patients would be comparable to previously reported outcomes in the adult population.

Study Design:

Case series; Level of evidence, 4.

Methods:

The study included patients who had undergone multiligament knee reconstruction at 19 years of age or younger and had at least 2 years of follow-up. All procedures were performed by the same surgeon. Exclusion criteria included patient age 14 years or younger at the time of surgery, open physes, prior ipsilateral meniscal or knee ligament surgery, or a tibial plateau fracture at the time of injury. Multiligament reconstruction was defined as a reconstruction of at least 1 cruciate ligament and at least 1 component of the posterolateral corner or the medial knee. Patients were evaluated according to Lysholm score, Tegner score, Short Form–12 physical component summary (SF-12 PCS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and postoperative patient satisfaction.

Results:

Twenty patients (mean age, 17.7 years; mean follow-up, 37.1 months) were included in this study. No patient required additional ligament surgery after the index surgery because of graft failure. The median preoperative Lysholm score was 49.5 (range, 18-90), and the median postoperative Lysholm score was 86 (range, 44-100) (P < .001). The median preoperative Tegner activity score was 2 (range, 0-9), and the median postoperative Tegner activity score was 6 (range, 2-10) (P = .012). The median SF-12 PCS improved from 40.5 preoperatively to a median of 56.1 postoperatively (P < .001). WOMAC total score improved from a median of 26.5 preoperatively to a median of 2 postoperatively (P < .001). Median postoperative patient satisfaction was 10 (range, 5-10).

Conclusion:

Single-stage multiligament knee reconstruction is a reliable procedure that improves knee function at 2-year follow-up in adolescent patients. Patient satisfaction was excellent, but longer follow-up in a larger series of patients is required to determine the long-term benefits of multiligament reconstruction in this patient population.

Traumatic Knee Dislocations: Evaluation, Management, and Surgical Treatment

Knee dislocations are catastrophic injuries that demand emergent evaluation and often require a multidisciplinary approach. Long-term outcome studies are relatively scarce secondary to the variability in any given study population and the wide variety of injury patterns between knee dislocations. Multiple controversies exist with regard to outcomes using various treatment methods (early vs late intervention, graft selection, repair vs reconstruction of medial and lateral structures, rehabilitation regimens). Careful clinical evaluation is essential when knee dislocation is suspected.

Pediatric Knee Dislocations and Physeal Fractures About the Knee

Given the high incidence of vascular and neurologic injury associated with pediatric knee dislocations and displaced physeal injuries about the knee, a thorough understanding of the clinical and radiographic signs associated with these injuries, relevant anatomy, workup, reduction techniques, and surgical management is crucial. A higher incidence of these injuries in children is anticipated because of increased participation in high-energy activities that result in contact or collision during sports or recreation. Complications, such as vascular and nerve injuries and compartment syndrome, can be diagnosed early in the workup to prevent catastrophic outcomes. The clinical examination should include evaluation of the motor and sensory status of the limb, palpation of pulses, and measurement of ankle brachial indices. Radiographic examination should include plain radiography and supplemental advanced imaging, if indicated. Vascular imaging or expert consultation should be considered when the pulse or ankle brachial index is abnormal on clinical examination. Selection of nonsurgical or surgical treatment depends on the fracture pattern and stability.