Digital radiographic measurement of normal knee joint space in adults at Kano, Nigeria

The measurement of knee joint space width (JSW), between the distal femur and the proximal tibia is an indirect way of measuring the tibio-femoral cartilage thickness, which is considered a valuable parameter, in assessing knee cartilage disease. This study is aimed at establishing normal references of JSW for use in diagnosis and follow up of knee cartilage diseases. This prospective study was conducted on 30° fixed-flexion erect knee computed radiographs of 160 adults. The JSW of both medial and lateral compartments of each knee was measured using in-built electronic calipers. The mean right medial and lateral JSW measured 4.74 mm ± 0.75 and 5.63 mm ± 0.86, respectively. The mean left medial and lateral JSW measured 4.74 mm ± 0.76 and 5.66 mm ± 0.87. No statistically significant difference was found between right and left knee JSW compartments. The radiographic reference values of the knee JSW were obtained, showing no significant gender variation in knee JSW. However, there is a decrease in JSW with increasing age.