gms | German Medical Science

Objectives: Malreduction and instability are most relevant in the development of posttraumatic osteoarthritis following tibial plateau fractures. Isolated ligament injuries of the knee joint and their effects on stability are demonstrated in numerous studies on quantitative measurement. These data have been lacking in tibial plateau fractures. The purpose of this study is to quantify postoperative instability of the knee joint after tibial plateau fracture.

Methods: Patients (n=57; mean age 50.8 ± 11.9 years) with a tibial plateau fracture who underwent surgery between 2014 and 2019 at a Level I trauma center were included in this study. The minimum follow-up time after surgery was 12 months. Knee stability was measured using the Laxitester® (ORTEMA Sport Protection, Markgröningen, Germany) and the Lachmeter (Equipamentos Ortopedicos LTDA, Preto, Brazil) device, measuring internal (IRO), external rotation (ERO) and tibial translation (AP). Measurements were performed in the supine position with 30° flexion. Dynamic valgus instability was measured using the Orthelligent system (OPED GmbH, Valley, Germany). All tests were performed on both the injured and the uninjured knee.

Results: The mean follow up time of this study was 3.9 years. Simple fractures (Schatzker I-III) were present in 51 % (n=29) and complex fractures (Schatzker IV-VI, Moore I-V) in 49% (n=28). All participants underwent surgical treatment by different approaches (61.4% lateral approach, 24.6% combined, 8.8% posterior, 5.3% medial).

There is a significant increase in rotation/translation at the injured knee compared with the uninjured knee (AP 78%, IRO 78.9%, ERO 54%). Simple fractures (Schatzker I-III) showed significantly higher instability in ERO and IRO compared with complex fractures (Schatzker IV-VI), whereas no significant difference was observed in ap translation. In contrast to posterior approaches, medial and lateral approaches significantly increase ap translation. Patients treated with medial approaches demonstrate higher dynamic valgus instability.

Conclusion: The majority of patients demonstrate measurable uni- or multidimensional instability after surgical treatment of a tibial plateau fracture. Of interest is the increased rotational instability in simple fractures. It remains unclear to what extent fracture type, surgical approach or posttraumatic inflammatory reaction are responsible for this.