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Background: During revision total hip arthroplasty, the acetabular component is often secured with screws to ensure initial press-fit stability. The purpose of the present study was to assess a series of acetabular revisions involving the use of a porous-coated acetabular component that was stabilized with peripheral screws and to evaluate the results in relation to the acetabular bone deficiencies that were present at the time of the revision procedure.Methods: From 1987 to 1991, 203 consecutive acetabular revisions were performed. In 142 hips, a severe acetabular bone deficiency that did not require an allograft was reconstructed with a porous-coated acetabular cup that was secured with a minimum of two peripheral screws. After an average duration of follow-up of 13.2 years, 134 hips were reviewed clinically and radiographically. The procedure was considered to be a clinical failure if the component was revised or if the postoperative clinical scores were poorer than the preoperative scores.Results: At the time of the most recent follow-up, 127 (95%) of the 134 hips were stable and clinically successful. The other seven hips (5%) were considered to have failed. Five of these seven hips failed because of an infection, and two failed because of aseptic loosening. Five (19%) of the twenty-seven hips with a Paprosky type-3A defect (a defect in which 30% to 50% of the host acetabulum is missing) failed.Conclusions: Revision total hip arthroplasty with use of a porous-coated acetabular component that is fixed with peripheral screws can provide long-term durability in hips with severe acetabular defects that do not require the use of an allograft (Paprosky type-1 and type-2 defects). We recommend that when an acetabular implant with peripheral screws is used for the treatment of a more severe (type-3) defect, the cup should be augmented with structural allograft to improve initial stability, or other implants should be utilized. [ABSTRACT FROM AUTHOR]

Background: Disruption of the extensor mechanism is an uncommon but catastrophic complication of total knee arthroplasty. We evaluated two techniques of reconstructing a disrupted extensor mechanism with use of an extensor mechanism allograft following total knee arthroplasty.Methods: Twenty consecutive reconstructions with use of an extensor mechanism allograft consisting of the tibial tubercle, patellar tendon, patella, and quadriceps tendon were performed. The first seven reconstructions (Group I) were done with the allograft minimally tensioned. The thirteen subsequent procedures (Group II) were performed with the allograft tightly tensioned in full extension. All surviving allografts were evaluated clinically and radiographically after a minimum duration of follow-up of twenty-four months.Results: All of the reconstructions in Group I were clinical failures, with an average postoperative extensor lag of 59 degrees (range, 40 degrees to 80 degrees ) and an average postoperative Hospital for Special Surgery knee score of 52 points. All thirteen reconstructions in Group II were clinical successes, with an average postoperative extensor lag of 4.3 degrees (range, 0 degrees to 15 degrees ) (p < 0.0001) and an average Hospital for Special Surgery score of 88 points. Postoperative flexion did not differ significantly between Group I (average, 108 degrees ) and Group II (average, 104 degrees ) (p = 0.549).Conclusions: The results of reconstruction with an extensor mechanism allograft after total knee arthroplasty depend on the initial tensioning of the allograft. Loosely tensioned allografts result in a persistent extension lag and clinical failure. Allografts that are tightly tensioned in full extension can restore active knee extension and result in clinical success. On the basis of the number of knees that we studied, there was no significant loss of flexion. Use of an extensor mechanism graft for the treatment of a failure of the extensor mechanism will be successful only if the graft is initially tensioned tightly in full extension.Level Of Evidence: Therapeutic study, Level III-2 (retrospective cohort study). See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Corrosion at the modular head-neck junction of the femoral component in total hip arthroplasty has been identified as a potential concern, although symptomatic adverse local tissue reactions secondary to corrosion have rarely been described.Methods: We retrospectively reviewed the records of ten patients with a metal-on-polyethylene total hip prosthesis, from three different manufacturers, who underwent revision surgery for corrosion at the modular head-neck junction.Results: All patients presented with pain or swelling around the hip, and two patients presented with recurrent instability. Serum cobalt levels were elevated prior to the revision arthroplasty and were typically more elevated than were serum chromium levels. Surgical findings included large soft-tissue masses and surrounding tissue damage with visible corrosion at the femoral head-neck junction; the two patients who presented with instability had severe damage to the hip abductor musculature. Pathology specimens consistently demonstrated areas of tissue necrosis. The patients were treated with debridement and a femoral head and liner exchange, with use of a ceramic femoral head with a titanium sleeve in eight cases. The mean Harris hip score improved from 58.1 points preoperatively to 89.7 points at a mean of 13.0 months after the revision surgery (p=0.01). Repeat serum cobalt levels, measured in six patients at a mean of 8.0 months following revision, decreased to a mean of 1.61 ng/mL, and chromium levels were similar to prerevision levels. One patient with moderate hip abductor muscle necrosis developed recurrent instability after revision and required a second revision arthroplasty.Conclusions: Adverse local tissue reactions can occur in patients with a metal-on-polyethylene bearing secondary to corrosion at the modular femoral head-neck taper, and their presentation is similar to the adverse local tissue reactions seen in patients with a metal-on-metal bearing. Elevated serum metal levels, particularly a differential elevation of serum cobalt levels with respect to chromium levels, can be helpful in establishing this diagnosis. [ABSTRACT FROM AUTHOR]

Background: Acetabular fixation during revision total hip arthroplasty in patients who have a nonsupportive superior dome and proximal migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be achieved reliably with use of a hemispherical porouscoated component alone. The purposes of the present study were to determine the long-term results associated with the use of a porous-coated hemispherical acetabular component, supported with a distal femoral structural allograft, for revision at the site of a Type-IIIa defect and to determine if graft resorption leads to late failure.Methods: Thirty-one patients who had an acetabular reconstruction with use of a distal femoral allograft for the treatment of a Type-IIIa defect between January 1985 and December 1990 were followed annually with clinical and radiographic evaluations. At the time of the latest follow-up, eight patients had died and one patient had been lost to follow-up. One of the patients who died had had a clinical failure at 4.5 years postoperatively and was included in the analysis. Therefore, twenty-three patients, who had had an average age of sixty-one years at the time of the index procedure, were evaluated at an average of 10.3 years postoperatively.Results: Five acetabular components were re-revised because of aseptic loosening at an average of 5.3 years after the index procedure. Radiographically, all but one of the remaining components were stable and showed evidence of bone ingrowth. The average Merle D'Aubigné and Postel hip score improved from 5 points preoperatively to 10 points at the time of the latest follow-up. Allograft bone resorption, although difficult to quantitate, was observed around six of the seventeen stable components and around two of the five components that failed clinically.Conclusions: Acetabular revision with use of a porous-coated acetabular component along with a structural distal femoral allograft for the treatment of a Type-IIIa defect demonstrated a high rate of clinical and radiographic success after an average of ten years of follow-up. [ABSTRACT FROM AUTHOR]

Background: Acetabular fixation during revision total hip arthroplasty in patients who have a nonsupportive superior dome and proximal migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be achieved reliably with use of a hemispherical porous-coated component alone. The purposes of the present study were to determine the long-term results associated with the use of a porous-coated hemispherical acetabular component, supported with a distal femoral structural allograft, for revision at the site of a Type-IIIa defect and to determine if graft resorption leads to late failure.Methods: Thirty-one patients who had an acetabular reconstruction with use of a distal femoral allograft for the treatment of a Type-IIIa defect between January 1985 and December 1990 were followed annually with clinical and radiographic evaluations. At the time of the latest follow-up, eight patients had died and one patient had been lost to follow-up. One of the patients who died had had a clinical failure at 4.5 years postoperatively and was included in the analysis. Therefore, twenty-three patients, who had had an average age of sixty-one years at the time of the index procedure, were evaluated at an average of 10.3 years postoperatively.Results: Five acetabular components were re-revised because of aseptic loosening at an average of 5.3 years after the index procedure. Radiographically, all but one of the remaining components were stable and showed evidence of bone ingrowth. The average Merle D'Aubigné and Postel hip score improved from 5 points preoperatively to 10 points at the time of the latest follow-up. Allograft bone resorption, although difficult to quantitate, was observed around six of the seventeen stable components and around two of the five components that failed clinically.Conclusions: Acetabular revision with use of a porous-coated acetabular component along with a structural distal femoral allograft for the treatment of a Type-IIIa defect demonstrated a high rate of clinical and radiographic success after an average of ten years of follow-up. [ABSTRACT FROM AUTHOR]