Arthrofibrosis Severity in Knees With Failed Total Knee Arthroplasties Differs With Magnetic Resonance Imaging Synovial Classification.

BACKGROUND

Treatment of stiffness following total knee arthroplasty (TKA) is complicated by a lack of a specific diagnosis for arthrofibrosis. Magnetic resonance imaging (MRI) provides a noninvasive means to generate and evaluate clinically diagnostic images of deep structures within the knee. The purpose of this study was to assess how the severity and location of arthrofibrosis observed on MRI relate to MRI synovial classifications and range of motion in primary TKA patients undergoing revision surgery.

METHODS

There were 137 patients (140 knees) scheduled for TKA revision surgery who underwent preoperative MRI and were assigned a global synovial classification (normal, abnormal, arthrofibrosis, infection, focal scarring, polymeric) and severity of arthrofibrosis (none, mild, moderate, severe) within the individual anterior and posterior compartments. Passive joint flexion and extension measurements were recorded intraoperatively.

RESULTS

The global synovial classification of arthrofibrosis had a greater prevalence of severe fibrosis within the anterior (25 of 42) and posterior (16 of 42) compartments as compared to other classifications (P < 0.0001). Reduced flexion and extension were found in patients who had a global synovial classification of arthrofibrosis (P < 0.0001). Reduced knee flexion was observed with greater anterior fibrosis severity, and reduced knee extension was observed with greater posterior fibrosis severity (P < 0.0001).

CONCLUSIONS

Anterior and posterior fibrosis severity differs across MRI synovial classifications. Further, the extent of joint flexion and extension differs by MRI synovial classifications and severity of compartment arthrofibrosis. The results of this study support that MRI presents an effective and noninvasive means to discern global and local synovial reactions within individuals undergoing revision TKA.