We investigated the relationship between the mechanical-anatomic axes and angles of the knee joint and functional levels of patients with primary osteoarthritis.
A total of 35 patients (27 females, 8 males; mean age 58+/-9 years; range 42 to 77 years) with knee osteoarthritis were included. After physical examination, weight-bearing anteroposterior x-rays of the knees were obtained, on which measurements of the following were made: mechanical axis deviation (MAD), medial proximal tibial angle (MPTA), anatomic tibiofemoral angle (aTFA), mechanical lateral distal femoral angle (mLDFA), and joint line congruence angle (JLCA). Pain was evaluated by both the Western Ontario McMaster Osteoarthritis Index (WOMAC) and a visual analog scale (VAS). Functional capacity was assessed using the physical function and global indices of WOMAC.
There was a moderate correlation between body mass index and the WOMAC global index (r=0.47, p<0.05). Radiographic evaluations revealed varus deformity in 28 patients. There was a correlation between aTFA and the physical function (r=0.47) and global (r=0.41) indices of WOMAC (p<0.05). Functional capacity and pain were not correlated with the other mechanical angles of the knee joint (p>0.05).
In view of our results, aTFA may be considered one important criterion in designing treatment and planning surgery for patients with primary osteoarthritis.