Clinical evaluation of the proximal tibiofibular joint in knees with severe tibiofemoral primary osteoarthritis

Despite the coexistence of primary arthritic involvement of the tibiofemoral and proximal tibiofibular joints (PTFJ), clinical features of the PTFJ in knees with severe femorotibial arthritis have not been described to date. The PTFJ in knees with primary osteoarthritis may be a source of lateral knee pain after total knee arthroplasty operations. This study seeks to address whether there is a relationship between the clinical findings and degeneration of the PTFJ in knees with severe tibiofemoral primary osteoarthritis. Sixty knees in 34 consecutive patients (31 females and 3 males; mean age 71 years; range 61–86 years) with Kellgren–Lawrence grades III–IV primary femorotibial arthritis were enrolled in this study in order to collect clinical data regarding the PTFJ. Radiographs showed 23 PTFJs were grade IV, 14 were grade III, and 23 were grade II. With regard to the type of PTFJ, 13 joints were horizontal and 47 were oblique. Pain and tenderness were observed in 13 PTFJs upon clinical exam (two horizontal and 11 oblique PTFJ types; grade II in five, grade III in two, and grade IV in six). Lateral hamstring tightness was found in 28 knees (24 oblique and four horizontal PTFJ types; grade II in 10, grade III in two, and grade IV in 16). Ten of the 28 PTFJs in knees with lateral hamstring tightness were painful during the physical examination. No significant relationship was found between PTFJ exam findings and PTFJ type (Fisher’s Exact test, p = 0.713), PTFJ grade of arthritis ( χ ² test, p = 0.700), or between hamstring tightness and PTFJ type ( χ ² test, p = 0.194). However, hamstring tightness was significantly correlated with the grade of arthritis in the PTFJ ( χ ² test, p = 0.004). Although degenerative disease of the PTFJ is commonly associated with degenerative disease of the knee joint, radiographic findings of the PTFJ in patients with severe degenerative knee osteoarthritis and varus malalignment do not correlate with clinical findings.