Abstract
Objective: to measure cartilage and bone acetabular erosion in patients treated with a bipolar hip hemiarthroplasty because of a femoral neck fracture.
Material and methods:
- 34 patients, 31 female. average age 72.9 +/− 7.1 years (56–90)
- Level of activity previous to fracture: 82.4% level III, 14.6% level II
- Displaced (Garden III and IV) fracture of femoral neck excluding pathologic fractures
- Hip hemiartrhoplasty with a JRI Furlong bipolar head (22.25 mm inner head), 30 patients with a Furlong HAP-coated uncemented stem and 4 patients with an auto-blocking-type Surgival cemented stem
- Follow-up: minimum 2 years, average 2.9 years (2–5)
- Clinical evaluation: Merle-DAubigne-Postel six-point scale for pain and for function
- Radiological evaluation: measure of joint line width at superior-lateral quadrant (weight bearing area), perpendicular distance from prosthesis head to Kohler line
- Statistical analysis: Kolmogorov-Smirnov, ANOVA, Bonferroni, Pearson, and Spearman tests
Results – Pain: average score 4.5 +/− 1.3 after 1 year, 4.7 +/− 1.3 after 2 years, 4.6 +/− 1.4 after 3 years
- Function: average score 4.7 +/− 1.1 after 1 year, 4.7 +/− 1.4 after 2 years, 4.8 +/− 1.3 after 3 years
- Radiological joint line: disappeared in 13 patients (38.2%) after 1 year, in 14 (41.2%) after 2 years, in 54.5% of patients after 3 years. Average joint line width in the other patients: 0.9 mm (0.6–1.3) immediately after surgery, 0.6 mm (0.4–0.8) after 1 year, 0.5 mm (0.3–0.7) after 2 years, 0.5 mm (0.2–0.7) after 3 years (p< 0.05)
- Distance from head to Kohler line: 5.7 +/− 3.8 mm (4.6–6.8) immediately after surgery, 4.6 +/− 3.7 mm (3.6–5.6) after 1 year, 4.3 +/− 2.9 mm (3.3–5.3) after 2 years, 4.0 +/− 3.3 mm (2.5–5.5) after 3 years (p< 0.05). There were 2 cases of acetabular protrusion.
Conclusions 1. Bipolar heads in hemiarthroplasty do not avoid acetabular erosion. 2. The radiological progressive erosion does not correlate with clinical worsening of the patients.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
