Pattern of Motion Restriction in Nigerian Patients with Knee Osteoarthritis

In the Western population, knee osteoarthritis (OA) has been shown to present a characteristic passive motion restriction pattern, called the capsular pattern (extension restriction to flexion restriction ratio ranging from 0.03 to 0.50). The pattern of motion restriction of Nigerian patients with OA has not been previously reported. This study was conducted to determine the pattern of motion restriction in Nigerian patients with knee osteoarthritis. Participants were 50 patients with knee OA (OA Group/OAG), recruited consecutively from two secondary health institutions and 50 age and sex-matched controls (Control Group/CG) without symptoms of OA. Goniometric measurements of passive and active knee motion of participants were taken. Data was analysed using the independent t-test. The OAG, aged 58.1±10.7 years has had OA for 4.0±4.5 years. The CG was aged 55.9±10.3 years. Mean active extension (1.5±5.2°) of the OAG differed significantly (P < 0.05) from that of the CG (0°), but the two groups did not differ significantly in passive extension (OAG = 1.2°±4.4°; CG = 0°). The CG (125.9°±4.6°) had significantly higher (P= 0.0001) active knee flexion than the OAG (99.9°±15.5°). Passive knee flexion of the CG (134.5°±5.0°) was significantly higher (P=0.000) than that of the OAG (110.4°±14.8°). Mean active extension and flexion restriction of OAG was 2.1±5.7° and 26.0±15.4° respectively. Mean passive extension restriction was 1.2±4.4° and passive flexion restriction was 24.0±14.8°, giving a ratio of 0.05 for OAG. Our findings suggest that the passive motion restriction pattern seen in Nigerian patients with knee osteoarthritis is the capsular pattern. KEY WORDS: motion restriction, patients, knee osteoarthritis