Summary

In this study, OsteoAMP® bone graft showed superior fusion rates as compared to rhBMP-2 at all timepoints (p<0.004). Additionally, OsteoAMP® bone graft had >80% few adverse events as compared to rhBMP-2.

The purpose of this study is to evaluate short to mid-term clinical and radiological results of metal on metal resurfacing arthroplasty in osteonecrosis of the femoral head (ONFH).

185 hips of 169 patients who underwent metal on metal resurfacing arthroplasty using Birmingham Hip Resurfacing system (Midland Medical Technololgies, Birmingham, UK) between December 1998 and May 2005 were available for this study and all cases were followed up over 3 years. All preoperative diagnoses were ONFH. The extents of necrotic area were analyzed by preoperative MRI scanning. Their mean age at the time of operation was 37.7(range, 16–67) years old and mean period of follow-up was 88(range, 36–113) months. For the clinical assessments, Harris hip scores, UCLA activity scores, pain and ROM were evaluated. Radiological changes such as radiolucencies around the stem, impingement sign, neck narrowing, osteolysis around head and neck junction, loosening of implants, heterotopic ossifications were evaluated in the serial antero-posterior, translateral radiographs of the hip joint.

Preoperative necrotic area was average 42.7(range, 11.5–60) %. Clinically, the average Harris hip score was improved from 85.2 points to 97.1 points at final follow-up. Average UCLA activity scores at the last follow-up was 8.8 and almost of the patients showed high activity and returned to their original job. ROM were very satisfactory. Radiologically, the mean inclination of acetabular component was 48.0°. There were no radiolucent lines around the acetabular components, but 3 cases showed radiolucent lines around the stem of femoral components. Osteolytic lesions were noticed in 10 cases around head-neck junction. Nine hips had impingement signs around the head-neck junction. There was no case which showed evidence of stress shielding. Moderate neck narrowing were shown in 3 cases. There were 6 cases of heterotopic ossification. One hip had a revision surgery to a total hip arthroplasty using big metal ball because of loosening of acetabular component. There was no patient complained limb length discrepancy and no infection, dislocation, thigh pain.

The midterm performance of metal on metal resurfacing arthroplasty in ONFH was very excellent in the aspects of pain relief, ROM of hip joints, rehabilitation and return to preoperative activity and minimization of common complications of conventional total hip arthroplasty. There was no mechanical failure related to the osteonecrosis and we can conclude that performing resurfacing arthorplasty in osteonecrosis less than 50% of extent can be justified. However, performing resurfacing arthroplasties in osteonecrosis of femoral heads needs meticulous surgical techniques and longer learning curve to prevent early failure. Even though our midterm follow-up study revealed excellent results, more long-term follow-up studies are mandatory to determine the survivorship and to verify the problems related to the increased serum metal ion and metal ion toxicity after resurfacing arthroplasty.

The purpose of this study is to analyze clinical and radiological results of total hip arthroplasty using the 3rd generation ceramic on ceramic articular surface.

Between July 1999 and May 2005, 339 hips of 250 patients had primary cementless total hip arthroplasty with the 3rd generation ceramic on ceramic bearing implants. And 325 hips of 236 patients were followed up over 3 years. Male were 168 patients(237 hips) and female were 68 patients(88 hips). The mean age at the time of operation was 47.3(range, 25~76) years old and the mean follow up period was 62.4(range, 36~107.6) months. The preoperative diagnoses were osteonecrosis of the femoral head (ONFH) in 250 hips, secondary osteoarthritis in 55 hips(dysplasia in 35, infection sequalae in 12, LCP in 2, CDH in 2), hemophilic arthropathy in 9 hips, ankylosing spondylitis in 7 hips etc.

We used Bicontact system(Aesculap, Germany) in 65 hips, Secur-FitTM(Stryker Howmedica Osteonics, USA) in 206 hips, Trilogy ABTM (Zimmer, USA) in 54 hips. Clinically, Harris Hip Score, thigh pain, squeaking and other complications were evaluated. Radiologically, the serial radiographs were analyzed.

Clinically, the Harris hip score was improved from preoperative 66.0(19~91) to 96.2(58~100) at the last follow-up. Radiologically, there was no loosening of implants and visible wear and osteolysis. Heterotopic ossifications were noted in 5 cases. In complications, there was dislocation in one case, periprosthetic fracture in 2 cases and thigh pain in 9 cases. Intermittent squeaking sound has occurred in 8 cases(2.5%). Among these, one case of loud squeaking which happened after fall down had revision surgery. There was no infection and fracture of ceramic implant.

Our midterm results of THA with the 3rd generation ceramic bearing system were very satisfactory and demonstrated that the 3rd generation ceramic bearings remain as an excellent bearing choice because of their superior wear characteristics. However, the results of this study suggests that the squeaking would be one of strong potential risk factors for failure of ceramic on ceramic total hip arthroplasty and we must be very cautious to prevent squeaking.