Abstract
Background: Resurfacing hip replacement is becoming increasingly used surgical option for young active patients with disabling hip arthritis.However there is a paucity of published literature describing complications and their avoidance.
Objective The objective of this study was to analyse 6 cases of postoperative subcapital fracture following hip resurfacing with a cohort of 54 cases that did not have a fracture and to identify factors associated with fractures risk.
Materials and Methods Between January 1999 and October 2003, 60 hips in 54 patients were treated with metal on metal resurfacing hip replacement (MMT Birmingham, UK).6 of these sustained a fracture just below the femoral component.The notes and radiographs were reviewed.Demographics data was recorded along with height, weight,smoking habits and medication usage including NSAIDS and antiepileptic use.The radiographs were studied for notching of the neck,offset difference as compared to normal and the stem shaft angle. The results were statistically analysed to determine any significant associations.
Results 57 hips in 51 patients were analysed for comparison. The mean age of the patients was 50 yrs (Range 34–67).In the fracture cases there were three men and three women with a mean age of 48 yrs.Five of six ( 83%) in the fracture cases had notching of the femoral necks compared to 9 (17%) out of 51 of the non fractured patients. The offset was significantly greater in the fractured group(52 ± 7mm) compared to the non fractured group (49 ± 7 mm).The increase in offset appeared to occur as a result of incomplete seating of tight fitting cemented femoral component. The head size appeared smaller in the fractured group but the difference was insignificant. There was no significant trauma in any of the cases. None of the patients who underwent resurfacing for AVN and cyst had a fracture. There were no other significant correlations
Conclusions Increased offset and notching are factors which predispose to fractures following resurfacing hip replacements. AVN and cysts were not associated with fractures in our series. We have changed the cementing technique using smaller volumes of freshly mixed simplex cement and now encourage protected weight bearing if intraoperative notching is noted or if osteoporosis is identified pre or peri operatively. We have had no fractures in the last 18 months.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
