The Biomechanical Results of Total Hip Resurfacing Arthroplasty

• Published in: Journal of bone and joint surgery. American volume Vol. 86; no. 1; pp. 40 - 46
• Main Authors: Silva, Mauricio, Lee, Kee Haeng, Heisel, Christian, Dela Rosa, Mylene A, Schmalzried, Thomas P
• Format: Journal Article
• Language: English
• Published: Boston, MA Copyright by The Journal of Bone and Joint Surgery, Incorporated 01.01.2004; Journal of Bone and Joint Surgery Incorporated; Journal of Bone and Joint Surgery AMERICAN VOLUME
• Edition: American volume
• Subjects: Adult; Aged; Arthroplasty, Replacement, Hip - methods; Biological and medical sciences; Biomechanical Phenomena; Diseases of the osteoarticular system; Female; Femur - anatomy & histology; Hip Prosthesis; Humans; Male; Medical sciences; Metals; Middle Aged; Osteoarthritis, Hip - diagnostic imaging; Osteoarthritis, Hip - surgery; Patient Selection; Prosthesis Design; Radiography; Statistics, Nonparametric; Treatment Outcome; Biomechanics; Human; Treatment; Prosthesis; Orthopedics; Diseases of the osteoarticular system; Rheumatology; Total; Resurfacing; Hip
• ISSN: 0021-9355; 1535-1386
• DOI: 10.2106/00004623-200401000-00007

BACKGROUND:With the advent of more wear-resistant bearings, there is renewed interest in resurfacing total hip arthroplasty. However, there is a paucity of information on the biomechanical results of this type of arthroplasty compared with those of contemporary total hip arthroplasty. METHODS:Using standardized radiographs, we measured and compared the biomechanical parameters that affect the hip joint reactive forces in fifty hips that had a metal-metal surface replacement with those parameters in forty hips that had a contemporary cementless total hip replacement performed during the same time-period by the same surgeon. RESULTS:On the average, the arthritic hips that were treated with metal-metal surface replacement had had a more valgus preoperative neck-shaft angle and less horizontal femoral offset than the normal, contralateral hips (p = 0.0003). After both the metal-metal surface replacements and the cementless total hip replacements, the hip center of rotation was medialized by approximately 6 mm. Both procedures were associated with an average increase in limb length of approximately 3 or 4 mm. After the metal-metal surface replacements, the horizontal femoral offset was essentially equal to the preoperative value, but both values averaged about 8 mm less than those on the normal, contralateral side (p < 0.00001). In the hips with a conventional total hip replacement, the horizontal femoral offset increased an average of 9.5 mm compared with the preoperative value and was an average of 5 mm more than that for the normal, contralateral hip (p = 0.001). CONCLUSIONS:The biomechanical results of total hip resurfacing depend on the preoperative anatomy of the proximal part of the femur. Limb lengthening of 1 cm can be achieved, but horizontal femoral offset is essentially unchanged by hip resurfacing. Horizontal femoral offset can be increased reliably with a contemporary total hip replacement. Arthritic hips of limbs that are more than 1 cm shorter than the contralateral limb or that have a comparatively low horizontal femoral offset may be better served by a contemporary total hip replacement. These biomechanical limitations should be considered in the selection of hips for resurfacing. LEVEL OF EVIDENCE:Therapeutic study, Level III-1 (case-control study). See Instructions to Authors for a complete description of levels of evidence.