Osteolysis, secondary to local and systemic physiological effects, is a major challenge in total hip arthroplasty (THA). While osteolytic defects are commonly observed in long-term follow-up, how such lesions alter the distribution of stress is unclear. The aim of this study was to quantitatively describe the biomechanical implication of such lesions by performing subject-specific finite-element (FE) analysis on patients with osteolysis after THA. A total of 22 hemipelvis FE models were constructed in order to assess the transfer of load in 11 patients with osteolysis around the acetabular component of a THA during slow walking and a fall onto the side. There were nine men and two women. Their mean age was 69 years (55 to 81) at final follow-up. Changes in peak stress values and loads to fracture in the presence of the osteolytic defects were measured.Aims
Patients and Methods
We report the outcome of 39 patients who underwent
a modified Pauwels’ intertrochanteric osteotomy for nonunion of
a femoral neck fracture following failed osteosynthesis. There were
31 men and eight women with a mean age of 47.2 years (34 to 59).
By Pauwels’ classification, there were 11 Type II fractures and
28 Type III fractures. The mean follow-up was 7.9 years (2 to 19).
In the 11 patients whose initial treatment had been osteotomy, union was
achieved in nine (81.8%). In 28 patients whose initial treatment
had been with a lag screw or a dynamic hip screw, union was achieved
in 27 (96.4%). Limb lengths were equalised in 14 of 16 patients
(87.5%) with pre-operative shortening. The mean neck-shaft angle
improved significantly from 100.5° (80° to 120°) to 131.6° (120°
to 155°) (p = 0.004). The mean modified Harris hip score was 85.6
points (70 to 97) and the mean modified Merle d’Aubigné score was
14.3 (11 to 18). Good to excellent functional outcomes were achieved
in 32 patients (88.8%). A modified Pauwels’ intertrochanteric osteotomy
is a reliable method of treating ununited fractures of the femoral neck
following failed osteosynthesis: coxa vara and shortening can also
simultaneously be addressed. Cite this article
