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BACKGROUND: Dislocation may complicate revision total hip arthroplasty (THA). We examined the correlation between the components revised during hip arthroplasty (femur only, acetabulum only and both components) to the rates of dislocation in the first and multiple revision THA. METHODS: We obtained data from consecutive revision THAs performed between January 1982 and December 2005. Patients were grouped into femur-only revision, acetabulum-only revision and revision THA for both components. RESULTS: A total of 749 revision THAs performed during the study period met our inclusion criteria: 369 first-time revisions and 380 repeated revisions. Dislocation rates in patients undergoing first-time revisions (5.69%) were significantly lower than in those undergoing repeated revisions (10.47%; p = 0.022). Within the group of first-time revisions, dislocation rates for acetabulum-only revisions (10.28%) were significantly higher than those for both components (4.61%) and femur-only (0%) reconstructions (p = 0.025). CONCLUSION: Although patients undergoing first-time revisions had lower rates of dislocations than those undergoing repeated revisions, acetabulum-only reconstructions performed at first-time revision arthroplasty entailed an increased risk for instability.

CONTEXTE: Il arrive que la dislocation vienne compliquer la révision des prothèses totales de la hanche (PTH). Nous avons analysé la corrélation entre les éléments révisés durant une arthroplastie de la hanche (fémur seulement, acétabulum seulement ou les 2 éléments) et le taux de dislocation qui accompagne une première ou de multiples révisions de PTH. MÉTHODES: Nous avons obtenu les données sur les révisions de PTH consécutives effectuées entre janvier 1982 et décembre 2005. Les patients ont été regroupés selon que la révision de leur PTH concernait le fémur seulement, l'acétabulum seulement ou les 2 éléments. RÉSULTATS: En tout, 749 révisions de PTH effectuées au cours de la période de l'étude répondaient à nos critères d'inclusion : 369 premières révisions et 380 révisions additionnelles. Les taux de dislocation ont été significativement moins élevés chez les patients soumis à une première révision (5,69 %) que chez les patients qui n'en étaient pas à leur première révision (10,47 %; p = 0,022). Dans le groupe soumis à une première révision, les taux de dislocation consécutive à une révision concernant uniquement l'acétabulum (10,28 %) ont été significativement plus élevés que dans les groupes qui ont subi des reconstructions des 2 éléments (4,61 %) ou du fémur seulement (0 %, p = 0,025). CONCLUSION: Même si les patients soumis à une première révision ont présenté des taux moindres de dislocation que ceux qui n'en étaient pas à leur première révision, les premières révisions d'arthroplastie impliquant une reconstruction de l'acétabulum seulement ont comporté un risque plus grand d'instabilité.

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Surface arthroplasty simulations were generated using 3-dimensional computed tomographic scans from 61 consecutive patients presenting with idiopathic osteoarthritis to evaluate the change in femoral component positioning that would allow optimal alignment when resurfacing a cam-type deformity. Anatomical parameters were measured to quantify the influence of the deformity on the insertion technique of the femoral implant. A modified femoral head ratio was initially calculated from plain radiographs to define the severity of cam deformity in these patients. A severe deformity required more superior translation of the entry point and greater reaming depth to allow safe insertion with optimal implant alignment. This could be achieved while preserving the leg length, minimizing the component size, and maximizing the amount of host bone contact, although the horizontal femoral offset was reduced. These findings suggest that the femoral component can be safely inserted by modifying the surgical technique despite progressive deformity of the femoral head.

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BACKGROUND: Most authorities recognize minimally invasive unicompartmental knee arthroplasty (UKA) as technically demanding with concerns regarding loss of implantation accuracy. We have previously reported on the potential inaccuracy of femoral intramedullary guides in UKA leading to poor component positioning. Our 3-dimensional analysis of alignment error showed that a short, narrow intramedullary rod inserted according to the manufacturer's specifications did not accurately find the direction of the anatomic axis, with errors occurring in both the coronal and sagittal planes. We sought to evaluate whether a fluoroscopic computer-assisted minimally invasive UKA procedure would improve the accuracy and precision in the placement of the femoral component in the coronal and sagittal planes compared with conventional surgery. METHODS: We performed a prospective study involving cohorts of 45 conventional versus 53 navigated UKAs. A single surgeon performed all surgeries over a 4-year period. RESULTS: Pain and knee function significantly improved in both surgical groups at 1 and 2 years after surgery. At a minimum of 1-year follow-up, radiographic evaluation revealed significant improvements in coronal alignment precision of the tibial component (p = 0.026) and sagittal alignment precision of the femoral component for the navigated group (p = 0.037). The use of a fluoroscopic computer-assisted technique did not significantly improve the accuracy of any of the alignment angles. CONCLUSION: We cannot justify the additional expense and complexity imposed by fluoroscopic navigation despite the observed improvements in alignment precision. Improved positioning precision may translate into a greater number of long-term functional results, but larger, longer-term studies are needed.

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OBJECTIVE: The purpose of this study was to describe the outcomes of patients with a severe stroke admitted to a specialized "slow stream" rehabilitation program and to develop a model to predict discharge destination. METHODS: Chart review of 196 consecutive non-ambulatory ("lower-band") stroke patients admitted between 1996-2001, to a specialized in-patient rehabilitation unit designed to accommodate the needs of patients with profound disabilities, and who were considered inappropriate for conventional inpatient rehabilitation programs. Special features of this program included the availability of an independent living unit, therapies tailored to individual tolerance and the opportunity to remain on the unit for an extended period until such time that the patients' rehabilitation potential had been maximized. RESULTS: Patients were admitted to the unit after a median of 49 days following stroke onset. Their median admission and discharge functional independence measure (FIM) scores were 46 and 70, respectively. The improvement in ability to perform self-care tasks was statistically significant (Z= -11.18, p<0.0001). By discharge, 54 patients (28%) were able to ambulate independently (with or without an assistive device), while 142 patients (72%) remained wheelchair dependent. Eighty-five patients (43%) returned to their own home upon rehabilitation discharge, while the remainder were admitted to nursing homes or hospitals closer to the patients' home. Admission FIM score, age, no previous history of stroke and male sex were the variables found to most strongly predict discharge home. CONCLUSIONS: Patients with severe strokes who received individualized care on a highly specialized stroke rehabilitation unit achieved impressive functional outcomes despite a lag of seven weeks post stroke before rehabilitation was initiated. Many patients were no longer wheelchair dependent and almost half returned home. Active rehabilitation should not be limited to "middle-band" stroke patients.

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