A Comparative Study of Clinical Outcomes and Functional Status after Knee Fracture and Knee Fracture Dislocation

The aim of this study was to compare outcomes of tibial plateau fracture dislocations (FD) with tibial plateau fractures alone. This study was an analysis of a series of tibial plateau fractures, in which FD was defined as a fracture of the tibial plateau with an associated loss of congruent joint reduction and stability of the knee, and classified by the Moore system. Patient data collected included demographics, injury information, and functional outcomes (short musculoskeletal function assessment [SMFA] score and Pain by the visual analog scale). Clinical outcomes at follow-up were recorded including knee range of motion, knee stability and development of complications. There were a total of 325 tibial plateau fracture patients treated operatively, of which 22.2% were identified as FD (n = 72). At injury presentation there was no difference with regard to nerve injury or compartment syndrome (both p > 0.05). FD patients had a higher incidence of arterial injury and acute ligament repair (both p < 0.005). At a mean follow-up of 17.5 months, FD patients were similar with regard to pain, total SMFA scores, and return to sports than their non-FD counterparts (p = 0.884, p = 0.531, p = 0.802). FD patients were found to have decreased knee flexion compared with non-FD patients by 5 degrees (mean: 120 and 125 degrees) (p < 0.05). FD patients also had a higher incidence of late knee instability and subsequent surgery for ligament reconstruction (p < 0.005 & p < 0.05). However, there was no difference in neurological function between groups at follow-up (p = 0.102). Despite the higher incidence of ligamentous instability and decreased range of motion, FD patients appear to have similar long-term functional outcomes compared with non-FD of the tibial plateau. While FD patients initially presented with a higher incidence of arterial injury, neurovascular outcomes at final follow-up were similar to those without a dislocation.