Uniplanar Coronal Tibiofemoral Subluxation in Patients After Multiligament Knee Injuries: A Multicenter Retrospective Case Series.

BACKGROUND

Uniplanar coronal tibiofemoral subluxation (UCTFS) in the setting of multiple ligament knee injury (MLKI) or knee dislocation (KD) has rarely been discussed, and the potential for missed diagnosis may significantly impact long-term outcomes.

PURPOSE: To describe the presentation, injury patterns, possible mechanical barriers for reduction, and management for isolated UCTFS after MLKI/KD.

STUDY

DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective chart review was conducted at 4 institutions to identify patients with KD or MLKI who were evaluated with or developed subsequent UCTFS from January 2001 to January 2024. UCTFS was defined as medial or lateral translation of the tibial plateau in reference to the femoral condyle as seen on coronal imaging (radiograph, computed tomography scan, or magnetic resonance imaging scan), with normal alignment seen on the sagittal imaging. Medical records were reviewed for demographic data, clinical presentation, physical examination, diagnostic imagining, examination under anesthesia, surgical finding, and procedures performed.

RESULTS

A total of 15 cases were included. Of these, 12 patients were subluxed laterally and 3 medially. UCTFS was diagnosed at different time points with 10 patients within 1 week, 2 patients between 1 and 6 weeks, and 3 patients after 6 weeks from injury. The most common mechanism of injury was a fall (33%), and the most common pattern of injury was a KD-3L (26.6%). A mechanical blockage to reduction was found in 9 (60%) cases. These included medial soft tissue sleeve incarceration (n = 4), bucket-handle meniscal tears (n = 3), concomitant patellar dislocation (n = 2), and a displaced tibial spine fracture (n = 1). Some patients experienced subluxation due to several sources of mechanical block. Uniplanar external fixation was utilized in 7 patients for management of their initial ligamentous injuries, coronal instability, or a traumatic vascular injury. Hinged external fixation was utilized in 2 patients who presented in a chronic fashion to counter the propensity to subluxation while allowing early motion.

CONCLUSION

UCTFS is a rare event that has several potential factors contributing to its cause, and ≥1 of these factors may need to be surgically addressed. Tibiofemoral subluxation can be found at various time points from injury, and awareness and monitoring for its development should be factored into the clinical decision-making. UCTFS is a challenging clinical dilemma that may require multiplanar or hinged external fixation to maintain reduction.