Acetabular Bone Deficiency Research Articles

Acetabular revision with use of a bilobed component inserted without cement in patients who have acetabular bone-stock deficiency.

Massive deficiency of acetabular bone stock is a challenging problem in the increasing number of patients who need a revision of a failed hip arthroplasty. The bilobed cup has been presented as one alternative reconstruction technique for hips with extensive acetabular bone loss. The purpose of this study was to assess the results with use of a bilobed acetabular component inserted without cement for revision reconstruction in hips with acetabular bone deficiency in order to clarify the indications for its use and to identify the factors that influence the clinical and radiographic outcome. Forty-one hips in thirty-eight patients had an acetabular revision with a bilobed acetabular component inserted without cement between December 1991 and December 1995. These hips were a subset of the 414 hips treated with an acetabular revision during the same period of time. One patient was lost to follow-up, and one died during the study period. Two patients who could not return for radiographic evaluation completed questionnaires. The remaining thirty-four patients (thirty-seven hips) were evaluated radiographically and clinically and were followed for an average of forty-one months (range, twenty-four to sixty-six months). Radiographic analysis demonstrated an improvement in the average vertical displacement of the hip center. At the time of the latest follow-up examination, 76 percent (twenty-eight) of the thirty-seven cups were stable, 8 percent (three) were probably unstable with a change in the screw position but no definite migration of the cup, and 16 percent (six) were unstable. Eight of the nine loose or probably loose components were in patients who had more than two centimeters of superior migration of the component and disruption of Kohler's line on preoperative radiographs. Additionally, implants were more likely to become unstable (demonstrating more than 4 degrees of change in the abduction angle or more than four millimeters of radiographic migration) when the inferior aspect of the component did not extend to or distal to the interteardrop line, which indicated that the component was undersized. On the basis of our early rate of probable or definite loosening of 24 percent (nine of thirty-seven cups) and the technical difficulties involved, we do not recommend the routine use of this component. We believe that this device is indicated when a patient has an oblong-shaped acetabular defect and the surgeon wants to correct an elevated hip center. However, the medial wall of the acetabulum (Kohler's line) should be intact if the failed component has migrated more than two centimeters. An alternative reconstruction technique, such as use of a structural allograft with or without an acetabular cage, is also an option in this situation.

Bilobed Oblong Porous Coated Acetabular Components in Revision Total Hip Arthroplasty

Thirty-eight oblong bilobed noncustom uncemented, porous-coated titanium acetabular components were used to reconstruct failed hip arthroplasties with large superior segmental acetabular bone deficiencies. No structural bone grafts were used. All patients were followed up for 2 to 5 years (mean, 3 years) after the operation. One patient (whose socket rested primarily on a structural bone graft from a previous procedure) had revision surgery for acetabular loosening. No other patients have had revision surgery or had another ipsilateral hip operation. At latest followup, 35 patients had no or mild pain and two patients had moderate pain. Two implants migrated more than 2 mm in the first year, then stabilized. On the latest radiographs, two implants had bead shedding, but there was no measurable migration or change in position. For selected patients with large superolateral acetabular bone deficiencies, this implant facilitated a complex reconstruction, provided good clinical results, and showed satisfactory stability at early to midterm followup in most patients.

Bone—graft augmentation for acetabular deficiencies in total hip arthroplasty: Results of long-term follow-up evaluation

The results of 102 consecutive primary and revision total hip arthroplasties performed with bone-grafting for acetabular bone deficiencies were reviewed at an average of 10.2 years (range, 4–18.6) after surgery. Ninety-one percent had structural bone defects and 57% had underlying developmental dysplasia of the hip. Overall acetabular revision rates for aseptic loosening were 8% at 5 years and 26% at 10 years. In addition, in the patients with developmental dysplasia who had primary hip arthroplasties, acetabular revision rates for aseptic loosening were 3 and 18% at 5 and 10 years, respectively. Ninety-six percent of all uninfected grafts incorporated. Bulk grafts fared better than particulate grafts. No difference in failure rate was noted between primary and revision hip arthroplasty, type of deficiency, or amount of graft coverage. Although early results are encouraging, acetabular failure increased significantly with longer follow-up evaluation; however, graft incorporation was successful and facilitated subsequent revision surgery.

Observer variation in the detection of acetabular bone deficiencies.

To determine observer variation in the detection of acetabular bone deficiencies, 42 pairs of frontal (AP) and lateral hip radiographs and CT studies for total hip arthroplasty patients obtained within an average of 4 weeks of each other were reviewed separately by five radiologists and one orthopedic surgeon. Interobserver variations were calculated for each individual reading the films using kappa values. The individual film readings were then compared with a consensus reading of the CT data. When separate observers were analyzed, agreement on plain film readings was slight to fair (av. kappa = 0.1440 +/- 0.1047). The individual observers were not able to give readings which were very consistent with the CT consensus reading, resulting in a low sensitivity (65%) and specificity (74%) for acetabular defect classification with plain radiographs. The identification of acetabular bone defects from the AP and lateral views of the hip is highly subjective and variable from observer to observer.

Acetabular supporting ring in total hip replacement.

A series of 14 total hip arthroplasties with a Müller acetabular supporting ring including 3 primary and 11 revision arthroplasties is reviewed. This device was used in cases of acetabular bone deficiency, and bone graft was added in 11 cases. The mean length of follow-up was 39.9 months. Twelve patients had good or satisfactory results, while two operations failed. These results indicate that the acetabular supporting ring is a useful implant in cases with acetabular bone stock deficiency.

Revision Total Hip Arthroplasty Using Allogenic Chip Bone Grafts and Cement in Acetabular Bone Deficiencies: Minimum Two Year Clinical and Radiological Analysis

Revision Total Hip Arthroplasty Using Allogenic Chip Bone Grafts and Cement in Acetabular Bone Deficiencies: Minimum Two Year Clinical and Radiological Analysis

Compressed allograft chips for acetabular reconstruction in revision hip arthroplasty

We report the results of 24 acetabular reconstructions in which cemented polyethylene cups and tamped corticocancellous allografts were used for severe acetabular bone deficiency. Eleven hips had type-II (cavitary) bone deficiency and 13 had type-III (combined) defects. At a mean follow-up of 5.8 years, two components had migrated more than 5 mm and had accompanying radiolucent zones of more than 2 mm width. A radiolucency 5 mm wide was also seen in zone III of an acetabular implant which had not migrated. None of the patients had required revision because of loosening or infection.

Bipolar revisions with bone-grafting for cavitary and segmental acetabular defects: A minimum 5-year follow-up study

Bipolar revisions used in massive uncontained acetabular defects often lead to high migration rates and early clinical failure. Reconstructions for less severe acetabular bone deficiencies were studied radiographically and clinically. Thirty-two bipolar revisions with bone-grafting were performed for cavitary and segmental acetabular defects. The average follow-up period was 6 years (range, 5–8.4 years). Medial migration averaged 2.3 mm (range, 0–7 mm), oblique migration averaged 2.9 mm (range, 0–8 mm), and superior migration averaged 5.9 mm (range, 0–15 mm). Continued migration at the final follow-up evaluation was noted in all but nine hips. Arrested migration was observed when cavitary defects were encountered. Segmental medial wall defects resulted in increased medial migration. Segmental superior rim defects resulted in large amounts of superior migration. Preoperative Harris hip scores averaged 47 before surgery and 86 at the final follow-up evaluation. Postoperative clinical scores did not deteriorate with radiographic evidence of progressive migration. Six reoperations for femoral complications of fracture or loosening were performed at an average of 4.7 years with concomitant conversion of the bipolar prosthesis to a fixed cementless cup. One rerevision was performed for acetabular disassembly at 6.6 years. When cavitary defects exist, allografting with a bipolar endoprosthesis can provide durable reconstructions with excellent clinical function. Bipolar revisions are also a relatively simple means of providing stability in recurrent dislocation cases.

High failure rate of bulk femoral head allografts in total hip acetabular reconstructions at 10 years

The authors evaluated the radiographic appearance and functional performance of 30 cemented total hip arthroplasty acetabular reconstructions in 28 patients in whom bulk, weight-bearing, femoral head allografts were used to augment severe acetabular bone deficiency with a mean follow-up period of 10 years (range, 8–13.3 years). The average age of the patients was 51 years. The current study group represents the 10-year subset of a larger series of 38 hip reconstructions previously reported. The graft was bolted within the acetabulum in 12 hips and to the lateral wing of the ilium in the other 18 hips. On average, these grafts supported approximately 60% of the acetabular component. All grafts united. Failure of fixation of the acetabular component occurred in 47% of the acetabular reconstructions (14 hips in 14 patients). Four were diagnosed as loose on the basis of radiographic criteria alone and the other 10 hips had a loose acetabular component at reoperation. Loosening occurred in 58% (7 of 12) of the sockets with intraacetabular graft and in 40% (7 of 18) of those bolted to the lateral ilium. The failure rate of 47% in these reconstructions at 10 years is in sharp contrast to high success rates at less than 5 years and argues against the use of bulk weight-bearing allografts for most situations uncless the only alternative is resection arthroplasty.

A clinical study of total hip arthroplasty in acetabular bone deficiency

A clinical study of total hip arthroplasty in acetabular bone deficiency

Revision arthroplasty using an anti-protrusio cage for massive acetabular bone deficiency.

Revision hip arthroplasty in patients with massive acetabular bone deficiency has generally given poor long-term results. We report the use of an 'anti-protrusio cage', secured to the ischium and ilium, which bridges areas of acetabular bone loss, provides support for the acetabular socket, and allows pelvic bone grafting in an environment protected from excessive stress. Forty-two failed hip arthroplasties with massive acetabular bone loss were revised with the Burch-Schneider anti-protrusio cage and evaluated after two to 11 years (mean five years). There was failure due to sepsis in five hips (12%) and aseptic loosening in five (12%); the remaining 32 hips (76%) showed no evidence of acetabular component failure or loosening.

Salvage total hip reconstruction in patients with major acetabular bone deficiency using structural femoral head allografts

We evaluated 38 hip reconstructions in 36 patients at a mean follow-up of 5.9 years (range 4 to 9.1) after femoral head allografts had been used to augment severely deficient acetabular bone stock. The patients were all relatively young and had many previous operations. Their pre-operative Harris hip rating averaged 46 points (range 18 to 73). All the allografts united and there were no infections. However, 12 acetabular components (32%) became loose; six of these had needed revision using the healed allograft, and two hips had required resection arthroplasty. The 30 surviving hips had a mean Harris hip score of 82 points. Some radiographic evidence of graft resorption was seen in 23 hips, though this was mild in 17. The extent of cover provided by the allograft and the severity of graft resorption both correlated with acetabular loosening. Although structural allografts had allowed successful hip reconstructions in many of these patients with major bone loss, the failure rate had increased from zero at four years to 32% at six years; clearly they provide only a short-term solution.