To evaluate the short-term clinical outcomes of metal-on-metal total hip resurfacing arthroplasty in treating osteonecrosis of the femoral head (ONFH) in young and middle-aged patients and to compare with patients of hip osteoarthritis at the same period.
From July 2006 to October 2008, 33 patients (45 hips) with ONFH (ONFH group) and 39 patients (45 hips) with osteoarthritis (osteoarthritis group) were treated with metal-on-metal total hip resurfacing arthroplasty. In ONFH group, there were 18 males (27 hips) and 15 females (18 hips) with an average age of 42.7 years (range 19-58 years), including 22 left hips and 23 right hips. The causes were trauma (4 cases), glucocorticoid (25 cases), drugs (2 cases), alcohol (1 case), and psoriasis (1 case). According to Steinberg classification, there were 10 hips at stage III, 18 hips at stage IV a, 13 hips at stage IV b, and 4 hips at stage IV c. The Harris score was 52.0 +/- 4.6. The disease course was 1-12 years. In osteoarthritis group, there were 26 males (30 hips) and 13 females (15 hips) with an average age of 47.1 years (range 42-65 years), including 17 left hips and 28 right hips. The causes were degenerative arthritis (23 cases), trauma (11 cases), and ankylosing spondylitis (5 cases). The Harris score was 57.0 +/- 3.8. The disease course was 3-17 years. There were no significant differences in general data between two groups (P > 0.05).
All incisions achieved healing by first intention without complications of infection and thrombosis of deep vein of lower extremities. The patients were followed up for 26 months in ONFH group and 28 months in osteoarthritis group. Femoral neck fracture occurred in 1 case of osteoarthritis group after 4 months, who received total hip arthroplasty; no complication of prosthesis loosening, dislocation, incision infection, osteonecrosis, and bone absorption occurred in other patients. At last follow-up, the Harris scores were 93.0 +/- 5.5 in ONFH group and 94.0 +/- 2.4 in osteoarthritis group, showing no significant difference between two groups (P > 0.05); but there were significant differences between pre- and post-operation (P < 0.01).
The clinical short-term outcomes of metal-on-metal total hip resurfacing arthroplasty to treat ONFH are satisfactory. It can achieve similar outcomes to that of osteoarthritis group. More cases and long-term follow-up are needed to investigate long-term clinical outcomes.