Bipolar hip arthroplasty for avascular necrosis of femoral head in young adults

Abstract

Background: Bipolar hip arthroplasty (BHA) is one of the options for treatment of avascular necrosis (AVN) of the femoral head. Acetabular erosion and groin pain are the most allowing for gross motion between the common complications. We propose that these complications are secondary to improper acetabular preparation allowing for motion between the BHA head and the acetabulum.

Materials and methods: The current study retrospectively evaluated patients'records from case files and also called them for clinical and radiological followup. 96 hips with AVN of the femoral head treated with BHA were included in the study. All patients were males with a mean age of 42 years (range 30-59 years). In all cases, the acetabulum was gently reamed till it became uniformly concentric to achieve tight fitting trial cup. Clinical followup using Harris hip score (HHS) and radiological study for cup migration were done at followup.

Results: The mean followup was 7.52 years (range 4-16 years). The HHS significantly improved from a preoperative value of 39.3 (range, 54-30) to a postoperative value of 89.12 (range 74-96). According to HHS grades, the final outcome was excellent in 52 hips, good in 28 and fair in 16 hips. Hip and groin pain was reported in four hips (5%), but did not limit activity. Subsidence (less than 5 mm) of the femoral component was seen in 8 cases. Subgroup analysis showed patients with Ficat Stage 3 having better range of motion, but similar HHS as compared to Ficat Stage 4 patients.

Conclusion: Bipolar hip arthroplasty (BHA) using tight fitting cup and acetabular reaming in AVN hip has a low incidence of groin pain, acetabular erosion and revision in midterm followup. Good outcome and mid term survival can be achieved irrespective of the Ficat Stage.

Keywords: Femoral head; Femur head; acetabular reaming; arthroplasty; avascular necrosis; avascular necrosis of bone; bipolar hip arthroplasty; femoral head prosthesis; hip.

Figure 1

(a) Peroperative photograph showing concentric acetabulum after superficial gentle reaming with the large hand reamer. (b and c) X-ray taken in neutral and abduction showing movement taking place mostly at inner bearing

Figure 2

X-ray right hip joint anteroposterior view in a 35 year old male showing (a) Preoperative radiograph with avascular necrosis right hip secondary to fracture neck femur. Also showing implant in situ (b) 4 years postoperative radiograph of the same patient treated with bipolar hip arthroplasty. (c) 16 years followup radiograph of the same patient without any loosening or migration and with subchondral sclerosis

Figure 3

(a) X-ray pelvis with both hip joints anteroposterior view in a 40 year old male showing avascular necrosis Ficat stage III in right hip (post alcoholic) (b) X-ray of right hip joint anteroposterior view of same patient showing Implant in position at 9 years followup without any sign of erosion or migration. (c) Clinical photograph of same patient showing cross legged sitting

Figure 4

(a) X-ray pelvis with both hip joints anteroposterior view in a 65 year old male showing posttraumatic avascular necrosis Ficat stage IV (see non concentric acetabulum) and implant in situ. (b) X-ray pelvis with both hip joints anteroposterior view of same patient at 9.5 years followup showing well fitting large cup. (c and d) Clinical photographs showing range of motion

Figure 5

X-ray pelvis with both hip joints anteroposterior view in a 45 year old man with bilateral avascular necrosis of femoral head (a) 6 months followup showing right side bipolar arthroplasty left side Ficat stage IV avascular necrosis. (b) At 5 years followup showing well fixed implant with large cup well placed in acetabulum