Abstract Background Added modular junction has been associated with implant-related failures. We report our experience with a titanium-titanium modular neck-stem interface to assess complications, ...possible clinical factors influencing use of neck modularity, and whether modularity reduced the incidence of dislocation. Methods A total of 809 total hip arthroplasties completed between 2005 and 2012 from a prospectively collected database were reviewed. The mean follow-up interval was 5.7 years (3.3-10.3 years). Forty-five percent were male (360 of 809), and 55% were female (449 of 809). All stems were uncemented PROFEMUR TL (titanium, flat-tapered, wedge) or PROFEMUR Z (titanium, rectangular, dual-tapered) with a titanium neck. Results Increased modularity (anteverted/retroverted and anteverted/retroverted varus/valgus (anteverted/retroverted + anteverted/retroverted varus/valgus) was used in 39.4% (135 of 343) of cases using the posterior approach compared with 6.8% (20 of 293) of anterior and 23.7% (41 of 173) of lateral approaches. Four males sustained neck fractures at a mean of 95.5 months (69.3-115.6 months) after primary surgery. Overall dislocation rate was 1.1% (9 of 809). The posterior approach had both the highest utilization of increased modularity and the highest dislocation rate (2.3%), of which the most were recurrent. The anterior (0.3%) and lateral (0%) approaches had lower dislocation rates with no recurrences. Conclusion At a mean 5.7 years, our experience demonstrates a low neck fracture (0.5%) and a low dislocation rate (1.1%). Use of increased modularity may not improve dislocation risk for the posterior approach. Continued surveillance of this group will be necessary to determine long term survivorship of this modular titanium implant.
Abstract Our initial experience with mobile bearing medial compartment unicompartmental arthroplasty (UKA) is presented to highlight lessons that have been learned to avoid short-term failures. ...Consecutive cases of the Oxford medial UKA performed between February 2001 and April 2006 were reviewed to derive those cases that were revised to total knee arthroplasty (TKA). There were 545 patients available with mean age and body mass index of 65.0 and 30.1, respectively. At final follow-up, 32 patients were revised for lateral compartment arthritis, aseptic component loosening, persisting medial or anterior pain and dislocated meniscal bearing. Revisions were performed with primary unconstrained TKA implants with no stems or wedges required. Our results seem to reflect those seen in registries confirming an earlier higher revision rate and highlight the technical issues of overstuffing the compartment, inadequate cementation technique, and strict adherence to patient selection.
Abstract The purpose of this study was to evaluate the clinical outcomes and possible causes of early failure in a multicenter trial of metal-on-metal hip resurfacing. Two hundred patients were ...prospectively enrolled and followed for an average of 31.2 months (range, 12-54 months). Of 200 patients, 14 (7.0%) required revision surgery at a mean time of 19.5 months (range, 3-47 months). Patients with failures were significantly younger and heavier than the nonfailures, and all were male. Patients who were revised did not differ from those who were not revised in terms of radiographic outcomes, but they did report lower functional outcome scores at all preoperative and postoperative testing intervals. Most failures (10/14) were related to early acetabular loosening. The learning curve was likely a factor in these cup failures. This report highlights the importance of patient selection and surgical technique in hip resurfacing arthroplasty. It is anticipated that further surgical experience will lead to a reduction in this high early failure rate.
The current study measured ion release among large-head metal-on-metal hip bearings. Twenty-six patients with a modular, Profemur® TL with A-Class® big femoral head total hip replacement were matched ...(gender, femoral size, BMI) with a group of 26 patients with the Conserve® Plus implant hip resurfacing. Compared with HR patients, THR patients had higher median serum cobalt ion levels at 6 months (3.26 vs 1.12 μg/L, P = .002) 1 year (4.51 vs 1.02, P = .002), and 2 years (3.77 vs 1.22, P <.001) following surgery. No differences in chromium ions were observed. Further research is required to determine the clinical significance of elevated serum cobalt ions.
Abstract Bone loss represents one of the greatest challenges in revision joint surgery. A retrospective review was conducted of both radiographic and clinical outcomes of eleven patients who ...underwent revision arthroplasty using a long extensively porous coated cylindrical femoral component. All patients' femurs presented with severe proximal femoral bone loss (Paprosky class IIIB and IV). With a mean follow-up of 8 years (2 to 14) we report no femoral revisions and one acetabular revision to a constrained cup secondary to instability. All patients were clinically and radiographically stable. We did not observe any issue with proximal stress shielding or component loosening. The article reports that in patients with severe proximal femoral bone loss, extensively porous-coated non-modular stems are a viable option offering stable and predictable outcomes.
Abstract We studied the technical operative features and the subjective outcomes of 63 patients requiring a revision to a total knee arthroplasty (TKA) for failed Oxford medial unicompartmental knee ...arthroplasty. We compared this revision study group to a contemporary control cohort of 126 patients who underwent primary TKAs. The 2 groups from the same institution had a minimum follow-up of 2 years and were retrospectively matched 1:2 for age, sex, body mass index, and follow-up time. Length of stay and hemoglobin level drop were similar. Technically, the revision group required larger polyethylene inserts ( P < .001) and longer tourniquet times ( P < .001) with 15 of these patients needing augments, grafts, and/or stems. Subjectively, the revision group's mean total Western Ontario and McMaster Universities Arthritis Index score was 25.8 ± 20.2, thus less satisfactory compared with the control group (19.8 ± 15.3) at a mean follow-up of 3.1 years ( P = .03). A revision unicompartmental knee arthroplasty to TKA is technically more difficult and functionally less satisfactory at last follow-up when compared with a primary TKA.
Abstract Restoration of retroacetabular bone stock by curettage and grafting with synthetics would obviate the need for autograft or allograft bone and prevent bone loss associated with revision. We ...conducted a clinical and radiographic review of 7 patients with progressive retroacetabular osteolysis. The size of the lesions ranged from 3.1 × 2.0 to 9.0 × 5.3 cm2 . All patients were treated with curettage and filling of the defects with calcium sulfate. Mean follow-up time was 48 months. On follow-up evaluation, there was resolution of 4 lesions, good osseous integration of 2 lesions, and no progression of 1 lesion. Curettage and grafting of progressive retroacetabular osteolysis with calcium sulfate and retention of components result in good osseous integration of the graft and halt the progression of lysis.
Background The purpose of the present study was to determine cobalt and chromium ion levels in the blood and urine of patients in whom a modern-generation metal-on-metal hip resurfacing device had ...been implanted. Methods A total of ninety-seven patients with a Conserve Plus metal-on-metal hip resurfacing implant were followed prospectively for two years. Cobalt and chromium levels in erythrocytes, serum, and urine were measured preoperatively as well as three, six, twelve, and twenty-four months postoperatively. Results The median serum cobalt and chromium ion levels were 1.04 μg/L (range, 0.31 to 7.42 μg/L) and 2.00 μg/L (range, 0.28 to 10.49 μg/L), respectively, at one year after surgery and 1.08 μg/L (range, 0.44 to 7.13 μg/L) and 1.64 μg/L (range, 0.47 to 10.95 μg/L), respectively, at two years after surgery. The corresponding mean levels (and standard deviations) of serum cobalt and chromium were 1.68 ± 1.66 μg/L and 2.70 ± 2.22 μg/L, respectively, at one year after surgery and 1.79 ± 1.66 μg/L and 2.70 ± 2.37 μg/L, respectively, at two years after surgery. Conclusions These levels compare favorably with other published ion results for metal-on-metal hip resurfacing and replacement implants. No pseudotumors or other adverse soft-tissue reactions were encountered in our study population. Further research is needed to determine the clinical importance of increased cobalt and chromium ion levels in serum and urine following metal-on-metal hip resurfacing. Level of Evidence Therapeutic Level IV . See Instructions to Authors for a complete description of levels of evidence.
Abstract We report a case of acute and recurrent accelerated wear of the polyethylene bushings of the hinge mechanism in the Zimmer Segmental Knee System. This resulted in an unacceptable recurvatum ...deformity leading to multiple revision knee operations, which was unexpected in a modern design hinged knee system. A custom modification of the original design was used to prevent further recurvatum deformity. The current design of the hinge post mechanism in this system appears to be inadequate, which led to the development of a significant recurvatum deformity in our patient. Surgeons should be aware of this potential complication when considering the use of this revision knee system.
