11-Year Mean Follow-Up of Acetabular Impaction Grafting With a Mixture of Bone Graft and Hydroxyapatite Porous Synthetic Bone Substitute

Background

We report an 11-year mean follow-up of the effectiveness of bone impaction grafting with bone and hydroxyapatite (HA) for large, uncontained acetabular defects in primary and revision hip surgeries.

Acetabular reconstruction with the Burch-Schneider ring: An EBRA analysis of 40 cup revisions

Background?Reconstruction of the bone stock and fixation of the implant remain challenging problems in revision surgery. In this retrospective study, we wanted to gain information on initial stability and wear after revision with the Burch-Schneider ring.

Patients and methods?Between 1994 and 1998, we performed 70 reconstructions of the acetabulum with a Burch-Schneider ring in revision arthroplasty. 63 patients could be followed up clinically and radiographically. 40 cups were suitable for EBRA measurements whereas migration and wear could not be assessed by this method in 23 cases due to lack of comparability of pelvic radiographs. The mean follow-up time was 4.7 years.

Results?2 cups were re-revised and 14 cups had breakage or changes of position of the screws. 30 cups showed detectable migration and 18 cups detectable wear. The mean migration was 2.8 mm and the mean wear rate was 0.12 mm/year. 16 cups had detectable migration after 1 year; 11 of these 16 continued to migrate and 9 of them had screw breakage. Both re-revisions showed early migration. Early migration correlated with later screw breakage and the overall migration correlated with wear. The only risk factor found for early migration was the wear rate.

Interpretation?The Burch-Schneider ring is an established and reliable implant for cup revision with good clinical results, but it seems to be difficult to maintain intraoperative stability. The implants with continuous migration may lead to late clinical failure and require further observation. Wear may contribute to migration and resorption of the bone graft.??     

Acetabular reconstruction with the Burch-Schneider ring: an EBRA analysis of 40 cup revisions

Background Reconstruction of the bone stock and fixation of the implant remain challenging problems in revision surgery. In this retrospective study, we wanted to gain information on initial stability and wear after revision with the Burch-Schneider ring.

Patients and methods Between 1994 and 1998, we performed 70 reconstructions of the acetabulum with a Burch-Schneider ring in revision arthroplasty. 63 patients could be followed up clinically and radiographically. 40 cups were suitable for EBRA measurements whereas migration and wear could not be assessed by this method in 23 cases due to lack of comparability of pelvic radiographs. The mean follow-up time was 4.7 years.

Results 2 cups were re-revised and 14 cups had breakage or changes of position of the screws. 30 cups showed detectable migration and 18 cups detectable wear. The mean migration was 2.8 mm and the mean wear rate was 0.12 mm/year. 16 cups had detectable migration after 1 year; 11 of these 16 continued to migrate and 9 of them had screw breakage. Both re-revisions showed early migration. Early migration correlated with later screw breakage and the overall migration correlated with wear. The only risk factor found for early migration was the wear rate.

Interpretation The Burch-Schneider ring is an established and reliable implant for cup revision with good clinical results, but it seems to be difficult to maintain intraoperative stability. The implants with continuous migration may lead to late clinical failure and require further observation. Wear may contribute to migration and resorption of the bone graft. ▪     

Cavitary acetabular defects treated with morselized cancellous bone graft and cementless cups

The use of impacted morselized cancellous bone grafts in conjunction with cementless hemispherical acetabular cups for treatment of AAOS type II acetabular cavitary deficiencies was evaluated in a retrospective study of 23 primary and 24 revision total hip arthroplasties, at a mean follow-up of 7.9 and 8.1 years, respectively. All primary hips received autografts, while all revision hips received allografts. Modified Harris Hip Scores for primary and revision hip replacements increased from a pre-operative mean of 37 and 47 to a postoperative mean of 90 and 86, respectively. All 23 autografts and 23 out of 24 cancellous allografts were radiographically incorporated without evidence of resorption. There were no instances of infection, component migration, or cases requiring subsequent acetabular revision. We conclude that impacted morselized cancellous bone-graft augmentation of cementless cups is a viable surgical option for AAOS type II cavitary acetabular defects.     

Decreased migration with locally administered bisphosphonate in cemented cup revisions using impaction bone grafting technique

Background and purpose — Impaction bone grafting (IBG) in revision hip surgery is an established method in restoring bone stock deficiencies. We hypothesized that local treatment of the morsellized allograft with a bisphosphonate in cemented revision would, in addition to increased bone density, also reduce the early migration of the cup as measured by radiostereometry (RSA).

Patients and methods — 20 patients with aseptic cup loosening underwent revision using the IBG technique. The patients were randomized to either clodronate (10 patients) or saline (10 patients, control group) as local adjunct to the morsellized bone. The outcome was evaluated by dual-energy X-ray absorptiometry (DXA) during the first year regarding periacetabular bone density and with radiostereometric analysis (RSA) for the first 2 years regarding cup migration.

Results — 2 patients were lost to follow-up: 9 patients remained in the clodronate and 9 in the control group. Less proximal migration was found in the clodronate group compared with the controls, measured both over time (mixed-models analysis, p = 0.02) as well as at the specified time points up to 2 years (0.22?mm and 0.59?mm respectively, p = 0.02). Both groups seemed to have stabilized at 1 year. We found similar bone mineral density measured by DXA, and similar RSA migration in the other directions. No cups were re-revised.

Interpretation — Local treatment of the allograft bone with clodronate reduced early proximal migration of the revised cup but without any measurable difference in periacetabular bone density.     

The fate of cementless jumbo cups in revision hip arthroplasty

We report 5-year minimum results of cementless over-sized cups used in revision hip arthroplasty, with significant associated bone defects. Forty-three porous-coated jumbo cups were used to treat acetabular defects in revision hip arthroplasty in 42 patients with a mean age of 63 (range, 25-86). Morsellized allograft only was used in 27 hips, and bulk allograft was used in 8 cases. Two patients were lost to follow-up, and 5 died after a mean 7 years' follow-up, with retention of their prostheses. In the remaining 36 cases, the mean follow-up was 10 years (range, 6-14 years). Two acetabular components were revised for aseptic loosening and graft resorption. Two cases were complicated by dislocation. A satisfactory 92% Kaplan Meier shell survival rate was seen at 14 years.     

Stability of Revision Acetabular Components Using the Rim-Fit Technique

Use of the rim-fit technique in revision acetabular surgery was reviewed for 20 hips in 18 patients. Defects at revision surgery included isolated medial segmental and global cavitary deficiencies with largely intact peripheral rim. A cementless acetabular component is placed to achieve a press-fit against the bony acetabular rim after morselized allograft and/or autograft was placed behind the cup. The average follow-up period was 68.3 months (5.7 years) (range, 27-112 months). Cup migration was assessed using digital radiography. Average vertical migration was 1.02 mm superiorly, and average horizontal migration was 0.8 mm medially. The abduction angle changed on average by 0.25°. Use of the rim-fit technique for treatment of cavitary acetabular defects is associated with component stability and minimal component migration.     

A controlled experimental model of revision implants: Part II. Implementation with loaded titanium implants and bone graft

We used an experimental model producing an aggressive tissue response associated with implant loosening in humans: a 6 mm polymethylmethacrylate (PMMA) cylinder was pistoning 500 &#119 m concentrically in a 7.5 mm hole, with polyethylene (PE) particles, for 8 weeks. At 8 weeks, the PMMA implant was revised with a titanium alloy (Ti) implant, and an identical primary Ti implant was inserted contralaterally for 4 weeks. With this protocol, we evaluated primary and revision plasma-sprayed Ti implants which were loaded under stable conditions with or without allograft, or under unstable conditions without allograft (bilateral primary and revision implants, n 8 per group, 48 implants in 24 dogs). Revision implants had lower interfacial shear strength, less bone in contact with and adjacent to the implant, and resulted in higher levels of IL-6 &#103 and TNF &#102 and lower levels of TGF &#103 . In both the revision and primary settings, allograft increased shear strength, stiffness and energy, bone-implant contact, and bone area adjacent to the implant. Unstable implants could not generate a mechanically sound interface, and further exacerbated the difference between primary and revision. We conclude that factors important for improving the fixation of revision implants were bone graft and a stable interface.     

2- to 10-year follow-up study of acetabular revisions using allograft bone to repair bone defects

The failure rates of revision of acetabular components have been high; however, long-term success has been reported with the use of particulate allografts or autografts with large-diameter prosthetic cups to correct bone deficiencies when host-cup contact is at least 30% to 50%. The purpose of this study was to review 2- to 10-year follow-up data on complex acetabular revisions in which contact between allograft bone and the prosthetic cup was at least 50%. In the 47 hips monitored clinically and radiographically for a mean of 5 years, results were classified as excellent in 37%, good in 26%, fair in 17%, and poor in 19%. The mean Harris hip score was 82.5 (range, 39–100). The prosthetic cups migrated in 3 hips, but 2 stabilized within 1 year. Three cups had complete radiolucent lines without migration; the lines did not correlate with location of the allografts. Although bone ingrowth into porous surfaces from allografts is debatable, the results of the study show that massive allograft reconstruction of the acetabulum can provide both immediate and long-term stability of the prosthetic cup and restore bone stock.     

Acetabular revision total hip arthroplasty using an impacted morselized allograft and a cementless cup: minimum 10-year follow-up

This study was undertaken to analyze the clinical and radiologic results of acetabular revision arthroplasty using an impacted morselized allograft and a cementless cup and was performed on 71 hips of 62 patients who were followed up for a minimum of 10 years (10 years to 14 years 8 months; mean, 12 years). The acetabular bone defects were classified using the American Academy of Orthopaedic Surgeons Committee on the Hip and Paprosky classifications. Cementless hemispherical cups were inserted via a press-fit technique, using an impacted morselized allograft. The mean Harris hip score at the last follow-up visit was 92. Only 3 cases were re-revised, and the 12-year survival rate was thus 95.8%. The study shows that acetabular revision arthroplasty using an impacted morselized allograft and a cementless cup is an excellent treatment option.     

Cortical and cancellous morselized allograft in acetabular revision total hip replacement: minimum 5-year follow-up

Sixty patients who had had revision acetabular components with impaction morselized bone graft were studied in a retrospective, matched-pair analysis. In 30 patients, the morselized graft was derived from cortical bone (group A), and in 30 patients, the graft was derived from cancellous bone (group B). The patients were matched for age, gender, weight, comorbid conditions, Charnley category, severity of bone loss, and allograft preparation. At the time of follow-up, a mean of 7.4 years (range, 5-9 years) after surgery, the mean Harris Hip Scores in groups A and B were 84 and 77, respectively. Cup migration of 5 to 10 mm were noted in two patients in each group. Cup migration >10 mm was noted in 2 patients from group B and none in group A. Two patients in group A and 5 patients in group B underwent cup rerevision as a result of aseptic loosening. There was a correlation between progressive radiolucent lines extending 2 mm, cup migration, and clinical outcome. The current study showed that early and midterm clinical and radiologic outcomes such as cup migration >5 mm and radiolucent lines were significantly better using cortical morselized allograft. However, further mechanical and histologic evaluations should be performed that demonstrate the difference between these 2 types of morselized allograft.     

Modes of failure of a threaded acetabular cup

A radiographic study of a singular type of threaded cup, revised due to aseptic loosening, was performed with Einzel-Bild-Roentgen-Analyse (EBRA) to detect eventual risk factors and patterns of loosening. Fifty-three cups of 50 patients were revised. Forty-two cups could be measured with EBRA. No cup had obvious osteolysis, 33 cups demonstrated early migration, and all cups had migrated at the time of revision. Twenty-eight of the cups had a change of inclination and 21 of anteversion, respectively. The mean migration was 1.9 mm in the medial and 7.9 mm in the cranial direction; the mean wear rate was 0.2 mm/year. Cups with early migration had a higher migration rate. All male patients had early migration; medially placed cups had less migration than the other cups. Wear was not significantly affected by the migration of the implant. No cup had a complete radiolucent line, and the only radiographic sign for loosening was the change of position of the cup. Medial placement showed less migration in case of loosening. Regular radiographic follow-up is recommended for the examined implant, and the cup should not be used in the future.     

Jumbo cups for revision of acetabular defects after total hip arthroplasty: a retrospective review of a case series

The treatment of acetabular bone defects presents a great challenge in revision total hip arthroplasty (THA). The purpose of this study was to evaluate the clinical and radiological outcome of revision THA using jumbo cups for acetabular reconstruction after applying the bone-grafting technique. We studied 17 patients with acetabular defects ranging from Type 2A to Type 3A according to Paprosky`s classification. According to the AAOS-score twelve patients were classified as Type II and five patients as Type III. Uncemented press-fit cups with an outer diameter larger than 64 mm were used in all cases. Fifteen patients received morselized bone allografts. In eight patients an additional screw fixation was necessary. The mean follow-up period was 82 months (range 33–149). The mean Harris Hip Score was preoperatively 62 and at the time of the last follow-up examination 83 points (p = 0.007). Two acetabular components failed, one due to aseptic loosening and another one due to septic loosening. There was a trend of displacement of the femoral head centre towards the infero-lateral position after using jumbo cups that approached statistical significance (p = 0.065). Closure of acetabular defects of Types 2A to 3A according to Paprosky’s classification and type II to III according to the AAOS-score respectively can be satisfactorily accomplished using jumbo cups after applying the bone-grafting technique.     

Use of structural bone graft with cementless acetabular cups in total hip arthroplasty

We retrospectively studied 15 primary and 13 revision total hip arthroplasties in which structural acetabular bone grafts were used in conjunction with cementless acetabular cups (for 11 type I segmental acetabular defects and 17 type III combined segmental/cavitary acetabular defects). Mean follow-up was 7.7 years in the primary and 6.8 years in the revision group. Radiographic analysis was performed to assess graft incorporation, component migration, bone-implant radiolucencies, and polyethylene wear. Two acetabular components (7.1%) were radiographically loose and demonstrated component migration. One of the two patients with these components also showed evidence of eccentric polyethylene wear. Three patients (10.7%) exhibited eccentric polyethylene wear. All grafts were well-incorporated radiographically without evidence of resorption. Modified Harris hip scores for all patients improved postoperatively.     

Unterschiedliche Pfannenrevisionsimplantate im Vergleich

Aseptic loosening of hip cups results in cranial and medial migration, which induces bone resorption and defects. Despite these defects, it is the aim in cup revision arthroplasty to get a stable fixation and a restoration of the hip center. Depending on the size of the defect, which can be classified by different scoring systems, various strategies requiring an experienced surgeon can be used to reach this aim. If defects are localized, bigger primary cemented or cement-free cups can be used. Larger defects may need bone transplantation or special designs such as oval cups or reinforcement rings. They can be used with or without plates in combination with cement for inlay fixation. In the case of bigger defects or pelvic discontinuity, modular systems or a socket cup may be necessary.     

15-year comparison of cementless total hip arthroplasty with anatomical or high cup placement for Crowe I to III hip dysplasia

This study compared radiological and clinical results of Mallory-Head (Biomet, Warsaw, Indiana) cementless total hip arthroplasty (THA) by anatomical (AP group) or high cup placement (HP group) for Crowe I to III developmental dysplasia of the hip. Of the 68 hips studied, 43 hips were available for 15.3-year follow-up. Ten cups were placed at anatomical center with bulk bone grafting, and 33 cups were at high hip center without bulk bone grafting. No acetabular or femoral components showed loosening in either group. One standard polyethylene liner in a highly placed cup was revised due to excessive wear after 11 years. The average rate of polyethylene wear was 0.128 mm/year in the AP group and 0.148 mm/year in the HP group (except for the revision case). The extent of grafted bone coverage was 34.6% in the AP group. Hip center height was 24.5 mm from the inter-teardrop line in the HP group. The center of the hip horizontal location in the AP group (24.5 mm) and HP group (26.4 mm) was significantly shorter than in normal hips (35.6 mm). Postoperative center-edge angle was 11° (except grafted bone) in the AP group and 25° in the HP group. Mean Harris Hip Score in the AP group improved from 38 points preoperatively to 82 points postoperatively and in the HP group improved from 40 points preoperatively to 88 points postoperatively. Survivorship was 100% in the AP group and 97% in the HP group. Our results indicate that moderate high cup placement without bulk bone grafting at a horizontal locus more medial than that of a normal hip is an alternative durable solution.     

An oblong revision cup for large acetabular defects: Design rationale and two- to seven-year follow-up

Loosening and migration of acetabular components often lead to extensive bony defects with an elongated, oval acetabular cavity. In these cases standard implants will not reestablish and maintain sufficient stability without leaving bone defects or using massive bone grafts or excess cement and additional metal rings or shells, disadvantages that are overcome by using an oblong revision cup without cement. The titanium shell is available in different sizes, is screwed to the autochthonous acetabular bone and houses an oblong polyethylene inlay, designed to reestablish the normal anatomic hip center. Of 109 consecutive revision cups, 102, implanted for American Academy of Orthopaedic Surgeons (AAOS) defects types I–IV, were followed up clinically and radiologically for 2 to 7 years (mean, 3.6 years). Primary stability was achieved in all cases. In 40% no bone grafting was necessary at all. The radiological follow-up revealed good remodeling of the surrounding bone and osseointegration of the implants. Zonal radiolucent lines, always smaller than 2 mm, were seen in 18 cases, only once completely and in only 5 cases partially progressing. Six cups migrated slightly (≤2 mm), two moderately (3–5 mm), all without clinical symptoms, and two more than 5 mm. Migration and radiolucencies were mainly seen in patients with allografts and major defects, which indicates that bone ingrowth appears more unlikely in such cases. Few asymptomatic cases showed zonal sclerotic lines. There were two aseptic loosenings, one in a case with pelvic discontinuity, the other in a patient with severe rheumatoid arthritis following two previous revisions. Survivorship analysis based on implant removal because of aseptic loosening as the endpoint shows a cumulative success rate of 98.1% at 8 years.     

Early proximal migration of cups is associated with late revision in THA

Background and purpose The association between excessive early migration of acetabular cups and late aseptic revision has been scantily reported. We therefore performed 2 parallel systematic reviews and meta-analyses to determine the association between early migration of acetabular cups and late aseptic revision.

Methods One review covered early migration data from radiostereometric analysis (RSA) studies, while the other focused on revision rates for aseptic loosening from long-term survival studies. Thresholds for acceptable and unacceptable migration were classified according the Swedish Hip Arthroplasty Register and the Australian National Joint Replacement Registry: < 5% revision at 10 years.

Results Following an elaborate literature search, 26 studies (involving 700 cups) were included in the RSA review and 49 studies (involving 38,013 cups) were included in the survival review. For every mm increase in 2-year proximal migration, there was a 10% increase in revision rate, which remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. Consequently, proximal migration of up to 0.2 mm was considered acceptable and proximal migration of 1.0 mm or more was considered unacceptable. Cups with proximal migration of between 0.2 and 1.0 mm were considered to be at risk of having revision rates higher than 5% at 10 years.

Interpretation There was a clinically relevant association between early migration of acetabular cups and late revision due to loosening. The proposed migration thresholds can be implemented in a phased evidence-based introduction, since they allow early detection of high-risk cups while exposing a small number of patients.     

Bipolar revision arthroplasty for failed threaded acetabular components: radiographic evaluation of cup migration

 We studied the radiographic results of bipolar revision hip arthroplasty in 25 patients (25 hips). These patients had suffered from osteoarthrosis of the hip due to acetabular dysplasia and had undergone total hip replacement using smooth threaded acetabular components. In the revision surgery, these components were replaced by bipolar cups; autografts were implanted in 23 patients and hydroxyapatite grains were added in 7. At the time of follow-up, the severity of migration was radiographically graded from I to IV: grade I, 5 mm or less; grade II, 6 to 10 mm; grade III, 11 to 15 mm; and grade IV, 16 mm or more. Five to 11 years (average, 7.0 years) after surgery, 9 patients were classified as grade I, 6 as grade II, 4 as grade III, and 6 as grade IV. Among the 6 individuals with grade IV migration, hydroxyapatite grains had been used in 5. There was a significant negative correlation between the distance of migration and the increase in size of the threaded acetabular components used in the primary total hip replacement and the bipolar cups in the revision surgery. Because of the tendency to migrate, we concluded that this procedure has a limited role in revision surgery. Received: November 9, 2001 / Accepted: March 15, 2002