Introduction

The different types of treatment for osteonecrosis of the femoral head have not led to a consensus about which treatment is best for the different stages. Particularly in the later stages of osteonecrosis, the disease still progresses to destruction of the femoral dome. The purpose of our study was to check the outcome of bone impaction grafting used for the head-preserving treatment of severe femoral head osteonecrosis. In order to preserve the femoral head, the sphericity and mechanical properties of the femoral dome must be contained and further collapse prevented.

Introduction The results of THA in patients with post-traumatic arthritis are inferior to those in nontraumatic arthritis, both after cemented and noncemented THA. This increased failure rate is caused by the bone stock loss and the abnormal anatomy. We studied the outcome of acetabular bone impaction grafting and a cemented cup in 20 cases at 3 to 18 years follow-up.

Materials and Methods Between January 1984 and January 2000 in 20 consecutive patients bone impaction grafting was used for arthritis after previous acetabular fracture, grafting was done in all for bone stock loss. There were 14 men and 6 women. The average age at THA was 53.3 years (range, 35 to 75 years). Defects were classified according to the AAOS acetabular defect classification (3 type I defects, 10 type II defects, 5 type III defects and 2 type V). Metal meshes were used in 6 medial wall and in 3 peripheral wall defects. In 15 cases autograft bone chips were used, in 5 both auto- and allograft was used. Grafts were impacted using impactors and a hammer and a PE cup was cemented. At review in January 2003 no patient was lost.

Results Two patients died during follow up after 3 and 4 years respectively, deaths were not related to surgery and data are included. The mean follow up was 9.5 years (range, 3 to 18 years). The pre-operative Harris hip score was 44 (32–61). During follow up a cup revision was performed in two cases; one for a culture proven septic loosening 14.5 years after surgery and the other for aseptic loosening at 15.3 years after surgery. Both revised cups were radiologically loose at revision. At review the 16 surviving hips had an aver. Harris hip score of 93 points (range, 62 to 100 points). Fourteen hips were free of pain, one patient had slight and one had mild pain.

Radiologically, none of these 16 cups was loose. However, two of the cups migrated more than 5 mm (e.g. 6 and 8 mm) relative to the initial post-operative X-ray. At review, both patients were symptom free.

The Kaplan-Meier survival rate of the cup with endpoint revision for any reason was 100% at ten years and 80% (95% CI, 62–98%) after 15 years; with endpoint cup revision for aseptic loosening the survival was 100% both at 10 and 15 years.

Conclusion The acetabular bone impaction grafting technique with a cemented cup is a biologically attractive technique to reconstruct the bone stock loss after posttraumatic arthritis with good long-term survival, even after long follow-up.

Aims: To test the outcome of acetabular revisons with impacted morsellized bone grafts and a cemented cup at a minimum follow-up of 15 years. Methods: Between 1979–1986 62 acetabular revisions (58 patients) were performed with impacted bone grafts and a cemented cup. Two cases (2 hips) were lost to FU. The average age at operation was 59.1 years. The indication was aseptic in 56 and septic loosening in 4 hips. Defects were AAOS-classiþed as ñcavitaryñ in 37 and ñcombinedñ 23 cases. Femoral-head allografts were used. Acetabular re-revisions were determined, the HHS obtained and radiographs analyzed. Results: Nineteen cases (20 hips) died within þfteen years after the operation, none had a re-revision. Eleven acetabular re-revisions were performed: 2 septic loosenings (3 and 6 years p.o.), 7 aseptic loosenings (6, 9, 11, 12, 13, 14, 14 year p.o.) and two for cup wear (12 and 17 yrs p.o.). The average HHS at follow-up was 86 (50–100). There were no additional radiographic failures. Using Kaplan-Meier analysis the survival with endpoint revision for any reason was 79% at 15 years and 71% at 20 years; for aseptic loosening of the cup 84% at 15 years and 84% at 20 years. Conclusions: This technique is attractive to reconstruct acetabular bone stock loss.

Introduction: Even in extensive osteonecrosis of the femoral head, a head-preserving method is preferable in younger patients. This study presents the results of bone impaction grafting for osteonecrosis of the femoral head.

Materials and Methods: After a core biopsy and removal of the osteonecrotic area, impacted morsellized bone allografts were used to fill the femoral head to regain sphericity, and to prevent collapse. This prospective, single-surgeon study included 28 consecutive hips in 27 patients with extensive osteonecrotic lesions (ARCO classification Stage 2 (11 hips), Stage 3 (14 hips), and Stage 4 (three hips). Fourteen hips had preoperative collapse. The mean age of the patients was 33 years (range, 15–55 years).

Results: At a mean follow-up of 42 months (range, 24–119 months), eight hips (29%) had been converted to a total hip arthroplasty. Of the 20 reconstructions that were in situ, 18 were clinically successful (90%) and 70% were radiologically successful. Patients who were younger than 30 years at surgery had a significantly better radiologic outcome, even when compared to heads with higher stages of osteonecrosis. Patients with preoperative collapse or a continuous use of corticosteroids had disappointing results.

Discussion: This method is attractive as a salvage procedure for osteonecrosis of the femoral head. It is relatively simple and quick to perform, and it does not intervene with an eventual future hip arthroplasty.

It has been generally accepted that dynamic mechanical load is important for normal bone physiology, remodeling and fracture healing. Impacted morsellized grafts can be seen as healing of many small fractured bone parts, involving bone remodelling, apposition and formation of new bone. Therefore load may be stimulative for the incorporation of this type of graft.

In a pilot study we observed a positive effect of load on the density of incorporated bone after 12 weeks. Based on these results we hypothesised that physiological loading has a stimulatory effect on the early stage of bone graft incorporation. To test this idea we implanted fresh frozen allograft bone chips in 12 goats and loaded these grafts with the newly developed subcutaneous pressure implant ( Lamerigts et al., Biomaterials2000; 21: 741–7). The goats were divided in two groups: non-loaded and loaded. The loaded group was subjected to a loading regime of 3 MPa for 5 days/week (1 Hz, one hour/day). After 5 weeks the bone mineral density was measured with quantitative CT scanning, followed by routine histology and histomorphometry.

Bone mineral density was not affected by load. Histology revealed microscopic evidence of normal bone graft incorporation as seen in previous studies. The amount of active incorporating bone was higher under load (p< 0.05).

The formation of a new bony structure was not affected by load in this early stage of bone graft incorporation. However, load resulted in a more active graft incorporation after 5 weeks. The difference between the loaded and non-loaded group might be partially obscured by a low level of physiological loading in the non-loaded group induced by the daily activity of the animals.