Evaluation of new version of Mecbio hip resurfacing prosthesis
Shu-Ang Wang1, Yu-Cheng Zhang2, Grant Lu-Sun Shih3
1Department of Orthopaedic, Taichung MetroHarbor Hospital, Taiwan
2Department of Orthopaedic Surgery and Rheumatology, The Fourth Hospital of Harbin Medical University, China
3Department of Radiology, Southwest International University, Taiwan
Keywords: Birmingham hip resurfacing prosthesis; customdesigned; hip resurfacing arthroplasty; total hip arthroplasty.
Objectives: The aim of this preliminary study was to compare clinical outcomes of the modern version of the Mecbio resurfacing arthroplasty prosthesis which is custom-designed for each patient with the older prototype which has three sizes.
Patients and methods: Between 2003 and 2008, 20 patients with hip disorders who underwent a total of 21 arthroplasties with the modern version or prototype prosthesis were included in the study. The prototype was used for the first 15 procedures, while the modern version was used for the last six procedures. The modified lateral approach was performed on all patients. Clinical and radiological examination were also performed by two experienced surgeons. Cortical changes of the calcar were evaluated by comparison of the thinner layer of the medial cortex with thickened one within 5 cm below the lesser trochanter. The patients were also clinically evaluated by the Harris Hip Score. The mean follow-up was three years (range, 2 to 5 years).
Results: There was a significant improvement in the Harris Hip Score following surgery compared to baseline between the groups (p<0.05). There was a significant increase in the prototype group (0.14±0.06 to 0.23±0.07, p<0.0001) and modern version group (0.15±0.07 to 0.25±0.03, p=0.0020) in terms of the thinner cortex and thickened cortex in the prototype group (0.21±0.06 to 0.28±0.06 p<0.0001) and modern version group (0.25±0.07 to 0.29±0.05, p=0.0156). There was no significant difference in terms of radiological measurements between the groups.
Conclusion: The results suggest that excellent clinical and radiological outcomes can be obtained with both the prototype and modern version prosthesis.