The Effect of Stem Alignment on Clinical and Radiographic Results of a Tapered CLS Stem / 대한정형외과학회잡지

PURPOSE: To examine the effects of the stem alignment on the clinical and radiographic results of a tapered wedge femoral prosthesis. MATERIALS AND METHODS: Ninety-one consecutive primary total hip arthroplasties were performed with an implantation of a CLS cementless femoral prosthesis between 1995 and 1998. Among them, 75 hips were retrospectively examined after a minimum duration of five years. The hips were divided into three groups based on the stem alignment; neutral stem alignment in 50 hips (67%), valgus in 15 hips (20%), and varus in 10 hips (13%). The clinical and radiographic results of the three groups were compared. RESULTS: There were no differences in the Harris hip scores and the incidence of thigh pain between the groups. Radiographic analysis revealed no difference in the fixation status at the latest follow up, nor was there any difference in the level of endosteal bone formation, the incidence of radiolucent lines, stressshielding, or osteolytic lesions. No loosening of the femoral stems was observed in any of the cases. CONCLUSION: Stem alignment of a tapered CLS femoral component does not compromise the clinical and radiographic results after a minimum follow-up of five years.

Hydroxyapatite Coated CLS Femoral Stem in Patients with Rheumatoid Arthritis: Minimum 5 Year Results / 대한정형외과학회잡지

PURPOSE: The study was undertaken in order to characterize the clinical and radiological results of total hip arthroplasty using a fully rough blasted stem with proximal hydroxyapatite coating in rheumatoid arthritis patients. MATERIALS AND METHODS: Twenty three total hip arthroplasties were performed using CLS stems in rheumatoid arthritis patients. Mean patient age of the patients and follow-up period were 53 and 6.8 years, respectively. Both clinical and radiographical parameters were evaluated. RESULTS: Chronological change of Harris hip score showed good results after 1 year. Harris hip score and the incidence of thigh pain at the last follow-up were 94 and one case, respectively. The mean time weight bearing without support was 12.5 weeks. Most endosteal bone formations around the stem appeared in the first 3 to 6 months. This was present in more than 80% of cases in zones 1, 2, 6, 7 and from 50 to 70% of cases even in zones 3, 4, 5 at the final follow-up. Loosening or implant failure was not found. Incomplete calcar fracture occurred in three cases, liner fracture around the femoral stem in one, heterotrophic ossification in one and superficial infection in one. CONCLUSION: The total hip arthroplasty using a CLS stem with a proximal HA coating may be a good choice in rheumatoid arthritis patients requiring hip arthroplasty.

10-15 Year Follow-up Results of Total Hip Arthroplasty Using a CLS (Cementless Spotorno) Stem for Osteonecrosis of the Femoral Head / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to evaluate the 10-15 year follow-up results of total hip arthroplasty using a CLS (Cementless Spotorno)stem for osteonecrosis of the femoral head. MATERIALS AND METHODS: Out of a series of 67 CLS stems implanted in patients with osteonecrosis of the femoral head from February 1988 to February 1993, 33 hips of 29 patients were studied for 10 to 15 years postoperatively. The average age at the operation was 46.8 years and the average duration of follow up was 12.3 (10-15 years) years. RESULTS: The average Harris hip score improved from 54.6 preoperatively to 95.8 postoperatively. Although one case showed radiologic stem loosening, no revision was performed because symptoms were not severe. Endosteal bone formation was observed in 29 (87.8%) casesand heterotophic ossification in 5. Acetabular cup loosening occurred in 1 case, and the acetabular revision was performed. Acetabularcup migration was not noted, though loosening was observed in the single case. CONCLUSION: Ten to fifteen year follow-up results of total hip arthroplasty using CLS stem for the osteonecrosis of the femoral head showedan excellent results with good osseointegration of the components. Therefore, we believe that CLS stem design and surface treatment is effective in terms of the longevity and produces good results.

Changes of Bone Mineral Density after Cementless Total Hip Arthroplasty: A quantitative comparison of two different implant designs / 대한정형외과학회잡지

PURPOSE: To compare the mineral density of periprosthetic bone around the two collarless stems, CLS and Alloclassic, which were same in composition and coating, but different in their shape and fit. It is known that the CLS stem is designed for metaphyseal fit and the Alloclassic stem is for upper diaphyseal fit. MATERIALS AND METHODS: In this matched cohort study, we performed DEXA scan using Hologic QDR-1000 on 20 patients, 9 of whom had CLS (Sulzer, Switzerland) femoral stem (group A), and 11 had Alloclassic (Sulzer, Switzerland) femoral stem (group B). BMD was obtained for seven zones of Gruen, and the difference was compared between the two groups. RESULTS: In group A, there was a significant decrease (P<0.05) of mean BMD in Gruen zones 1, 2 and 7 compared to normal side. In group B, there was a significant decrease (P<0.05) of mean BMD in Gruen zones 1, 2, 3, 4, 6 and 7 compared to normal side. Comparing the percent decreases of BMD, the only significant difference was observed in Gruen zone 1, in which group B showed more than 10% decrease than group A (P<0.05). CONCLUSION: Our findings suggest that the design of stem affects postoperative changes of BMD, and that the stem with more proximal fit would behave better in terms of stress shielding.