Comparison Between Standard and elevated-rim Acetabular Liner in Total Hip Arthroplasty / 대한정형외과학회잡지

PURPOSE: Elevated-rim acetabular liner enhances stability in total hip arthroplasty and has been widely accepted. But it has potential adverse effects. So, we assessed the effects of the elevated-rim acetabular liner clinically and radiologically. MATERIALS AND METHODS: We reviewed the results of 74 total hip arthroplasties of 64 patients that had been performed from January 1993 to March 1995. Thirty-six cases of the 74 cases used elevated rim acetabular liner and 38 cases did standard liner. Dislocation rate, Harris hips score, osteolysis and revision rate were compared between two groups. RESULTS: There were no significant differences in mean anteversion, abduction angles of the cup and femoral offsets between two groups. Four of the 38 cases with the standard liner had a dislocation, compared with one of 36 cases with the elevated-rim liner (P=0.358) . Femoral osteolysis was observed 7 cases (18.4%) in the standard liner group and 14 cases (38.8%) in the elevated-rim liner group. Acetabular osteolysis was observed 17 cases (44.7%) in the standard group and 21 cases (58.3%) in the elevated-rim group. Nine cases (23.6%) had been revised in the standard group and 6 cases (16.6%) in the elevated group. CONCLUSION: Excessive wear and breakage of the polyethylene by impingement was developed in the elevated-rim polyethylene liner.

The Results of the Treatment Using the Posterior Pedicular Screw System for Lumbar Isthmic Spondylolisthesis in Adult / 대한척추외과학회지

STUDY DESIGN: This study analyzed the efficacy of the reduction and its maintenance using the posterior pedicular screw system in adult patients undergoing surgical treatment for symptomatic, isthmic spondylolisthesis. OBJECTIVE: To evaluate the effect of the reduction for lumbar isthmic spondylolisthesis in adult. SUMMARY OF LITERATURE REVIEW: If the increase of the shear force is approved as a main biomechanical feature of spondylolisthesis, reduction of the shear forces to the physiologic level must be regarded as the goal of surgical treatment. MATERIALS AND METHODS: 11 cases were treated with posterior monosegmental two point f;cation and posterolateral fusion (Group 1), 8 cases with a combined surgery of posterior monosegmental two point fixation, posterolateral fusion and anterior interbody fusion (Group 2), and 20 cases with posterior two segmental three point fixation and posterolateral fusion (Group 3). We assessed the clinical results and the radiologic objective parameters. RESULTS: The patients were followed up for more than 2 years (mean : 64 months). The satisfactory clinical results were 9 cases (81.8%) in Group 1 ,7 cases (87.5%) in Group 2 and 17 cases (85%) in Group 3. Radiologically, the efficacy of reduction and its maintenance were satisfactory results in Group 2, and the changes of the slip angle and the disc height showed that the loss of correction was greater than postoperative correction, although there were no statistical significant differences in the three groups. CONCLUSION: According to the our results, there was no significant relationship between the clinical result and the rdiological one. However, we think that the correcton of the deformity using the posterior pedicular screw system have some biomechanical advantages and seem to be recommendable for the treatment of isthmic spondylolisthesis in adults.

THR with Hydroxyapatite - coated Hip Prosthesis / 대한정형외과학회잡지

Synthetic hydroxyapatite is a safe, nontoxic, biocompatible, and osteoconductive material. Hydroxyapatite-coated implants have the property of achieving a very strong bond with living bone in a relatively short period. From March 1992 to June 1994, 140 hydroxyapatite-coated primary total hip prostheses were implanted. This study included 60 cases that could follow up minimum 3 years. At the time of mean follow up, 45 months after operation, the mean Harris hip score was 92 points. Only two patients complained of thigh pain at last follow up. On radiographic evaluation, radiolucent lines were seen around the uncoated distal part of the stem in 46 percents of the implants. No radiolucent line was observed around the coated area of the prosthesis. Cancellous condensation was seen in 95 per cents of the implants at the Gruen zone 2 and 6 area. Cortical hypertrophy was present in 32 percents. Fourteen cases had the gaps at the bone to acetabular cup interface in the immediate postoperative period. The gaps disappeared in 12 months after operation. Five implants were revised because of polyethylene wear, cup migration and periprosthetic fracture. The clinical outcome was excellent. But this result was obtained in the relatively short-term follow up. Longer-term data will be the only true test of the value of hydroxyapatite coated implant.