Extra-large uncemented hemispherical acetabular components for revision total hip arthroplasty

Mid- to long-term results of irradiated allograft in acetabular reconstruction

Between 1990 and 2000, 123 hips in 110 patients were reconstructed for aseptic loosening using impaction bone grafting with frozen, irradiated, morsellised femoral heads and cemented acetabular components. This series was reported previously at a mean follow-up of five years. We have extended this follow-up and now describe the outcome of 86 hips in 74 patients at a mean of ten years. There have been 19 revisions, comprising nine for infection, seven for aseptic loosening and three for dislocation. In surviving acetabular reconstructions, union of the graft had occurred in 64 of 67 hips (95.5%).

Survival analysis for all indications at ten years was 83.3% (95% confidence interval (CI) 68 to 89) and 71.3% (95% CI 58 to 84) at 15 years.

Acetabular reconstruction using irradiated allograft and a cemented acetabular component is an effective method of reconstruction, providing results in the medium- to long-term comparable with those of reported series where non-irradiated freshly-frozen bone was used.

Acetabular revision with bone graft and cementless cup

Cementless acetabular components are routinely used in revision hip surgery. Nevertheless, few investigators have assessed their retention and efficacy over the long term. This occurs mainly in cases which originate from moderate to severe bone losses (cavitary and or segmental) requiring the use of morselized and or bulk bone graft. Our objective in the present study is to report the outcome of 42 patients with 43 cementless acetabular revisions with bone graft who were operated by the same surgeon. The report is based on the clinical and radiographic evaluation of the patients alive at 167 months of follow-up.

Porous tantalum uncemented acetabular shells in revision total hip replacement: two to four year clinical and radiographic results

In cementless revision total hip arthroplasty (THA), achieving initial implant stability and maximising host bone contact is key to the success of reconstruction. Porous tantalum acetabular shells may represent an improvement from conventional porous coated uncemented cups in revision acetabular reconstruction associated with severe acetabular bone defects. We reviewed the results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects done with a hemispheric, tantalum acetabular shell and multiple supplementary screws. At a mean follow-up of 40 (24-51) months, one acetabular shell had been revised in a patient with a Paprosky 3B defect. Cementless acetabular revision with the tantalum acetabular shell demonstrated excellent early clinical and radiographic results and warrants further evaluation in revision acetabular reconstruction associated with severe acetabular bone defects.

The Effectiveness of the Burch-Schneider antiprotrusio cage for acetabular bone deficiency: five to twenty-one years' follow-up

From 1985 to 2001, the Burch-Schneider antiprotrusio cage (B-S APC) was implanted in 57 cases (55 patients) with massive acetabular deficiency. The B-S APC survived until the last review 5 to 21 years after operation in 89.5% of the cases, produced substantial pain relief, and increased range of hip motion and walking capacity. The 10.5% failure rate was due to aseptic loosening in 2 cases and mechanical failure in 4 cases. It appears that application of the B-S APC in extensive acetabular deficiency presents a durable solution provided that proper indications and technique are used.

The Long Oblique Revision component in revision arthroplasty of the hip

Migration of the acetabular component may give rise to oval-shaped bone defects in the acetabulum. The oblong implant is designed to fill these defects and achieve a stable cementless anchorage with no significant bone loss. We prospectively reviewed 133 oblong long oblique revision components at a mean follow-up of 9.74 years (0.6 to 14). All had been used in revisions for defects of type IIB to IIIB according to Paprosky. Aseptic loosening was the reason for revision in 11 cases (8.3%) and deep infection in seven (5.3%). The probability of implant survival over a 12-year follow-up estimated by the Kaplan-Meier method gave a survival rate of 0.85% respectively 0.90% when deep infection was excluded as the endpoint.

Our study supports the use of these components in defects from IIB to IIIA. The main precondition for success is direct contact of more than half of the surface of the implant with the host acetabular bone.

Modular tantalum augments for acetabular defects in revision hip arthroplasty

Large acetabular defects can be reconstructed with various methods depending on size and location of the defect. We prospectively followed our first 37 patients in whom we reconstructed the acetabulum with a trabecular metal augment combined with a trabecular metal shell. Three patients died before completing the minimum 24 months followup while the remaining 34 were followed a minimum of 24 months (mean, 34 months; range, 24-55 months). All defects were classified according to Paprosky. Radiographic signs of osseointegration were classified according to Moore. Quality of life was measured with the SF-12, WOMAC, and Oxford Hip Score. There were 15 men and 19 women with an average age of 64 years. At a minimum of two years followup 32 of the 34 patients required no further surgery for aseptic loosening, while two had rerevision. Of the 32 patients who had not been revised, all had stable cups radiographically. All quality-of-life parameters improved. The early results with tantalum augments are promising but longer followup is required.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Why revision total hip arthroplasty fails

Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision THAs. The minimum followup was 2 years (mean, 6 years; range, 0-20.4 years). Eighty-seven percent of revision total hips required no further surgery; however, 141 hips (13%) underwent a second revision at a mean of 3.7 years (range, 0.025-15.9 years). Seventy percent (98 hips) had a second revision for a diagnosis different from that of their index revision, while 30% (43 hips) had a second revision for the same diagnosis. The most common reasons for failure were instability (49 of 141 hips, 35%), aseptic loosening (42 of 141 hips, 30%), osteolysis and/or wear (17 of 141 hips, 12%), infection (17 of 141 hips, 12%), miscellaneous (13 of 141 hips, 9%), and periprosthetic fracture (three of 141 hips, 2%). Survivorship for revision total hip arthroplasty using second revision as endpoint was 82% at 10 years. Aseptic loosening and instability accounted for 65% of these failures.

LEVEL OF EVIDENCE

Level IV, therapeutic (retrospective) study. See the Guidelines for Authors for a complete description of levels of evidence.

Acetabular revision arthroplasty using jumbo cups: an experience in Asia

INTRODUCTION

Variable degrees of bony deficiencies often complicate revisional arthrolasties of acetabular components and represent challenges to orthopedic surgeons. Many solutions exist and cementless jumbo cup reconstruction had been proven to be a feasible and successful method. Our study aimed to access the results of these cementless giant cups for managing acetabular bony defect at one institute.

MATERIALS AND METHODS

Between March 2000 and March 2003, 47 revisions of the failed acetabular components using the so-called "Jumbo Acetabular Cups" were enrolled in our study. All cases were followed for at least 4 years. We defined the size of the jumbo cups for the Asians to be of an outside diameter of 64 mm for men and 60 mm for women, which were 2 mm smaller than the commonly used definition in the Western countries. The radiographic outcomes and the migration of hip centers were analyzed. The endurance of these giant sockets was estimated by the Kaplan-Meier analysis.

RESULTS

After a mean follow-up of 65 months, only three implant failures requiring re-revision were identified. The estimated 5-year survival rate according to the Kaplan-Meier analysis was 94.5%. Radiographic analysis demonstrated an improvement of vertical hip center from 31 to 27 mm proximal to the interteardrop line. Eight (17%) cups exhibited radiolucent line around the bone-prosthesis interface but did not attenuate implant instability. The complication rate was not high. Dislocation happened in five (11%) patients. One deep infection was successfully reconstructed in stage surgeries after eradication of the infection.

CONCLUSION

With the aid of novel implant-coating technique and materials, jumbo cup reconstruction can achieve stability and longevity through an adequate peripheral ring-contact, regardless of inadequate implant to host bone contact. We believe that this is a reliable and easily performed reconstruction for acetabular defect.

Acetabular cage survival and analysis of factors related to failure

The reported results of acetabular cage reconstruction for pelvic deficiency are widely variable. Our primary question was: what is the survivorship of cage reconstruction with a primary end point of cage revision and secondary end points of radiographic loosening and any reoperation? Secondary questions were: which factors predict cage failure, and what is the functional outcome (SF-36, WOMAC, Harris hip score) of this reconstructive method? We reviewed 72 cage reconstructions in 68 patients. Minimum followup was 1.2 years (mean, 5.1 years; range, 1.2-10.7 years). Five-year cage revision-free survivorship was 87.8%. Five-year loosening-free and acetabular reoperation-free survivorships were 80.7% and 81.3%, respectively. No single preoperative factor (age, gender, severity of pelvic defect, degree of heterotopic ossification, difference in limb lengths and centers of rotation) or intraoperative factor (type of bone graft, type of cage, changes in limb length and center of rotation) predicted cage failure. Functional outcomes were 28.9 (SF-36 Physical Component), 52.4 (SF-36 Mental Component), 33.7 (WOMAC), and 44.2 (Harris). We judged these outcomes acceptable for this sometimes challenging problem. Future techniques for treating pelvic deficiency will need to be compared with these and other outcomes in the literature.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

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.

Cementless hemispheric acetabular component for acetabular revision arthroplasty: a 5- to 19-year follow-up study

This study evaluated the 5- to 19-year clinical and radiographic results of cementless acetabular revision. Between 1986 and 1998, 130 hips (125 patients) underwent cementless acetabular revisions. Ten patients were lost to follow-up; 6 patients died. One hundred nine patients (114 hips) were reviewed at a mean follow-up of 8.8 years. The mean Harris hip score improved from 62.1 to 90.7 at final follow-up. Two hips underwent repeat revision. Twenty-two hips developed cavitary osteolysis. Kaplan-Meier survivorship at 121 months was 98.2% with repeat revision for any reason as the end point and 89.5% with repeat revision or radiographic loosening as the end point. Cementless acetabular revision provides favorable clinical and radiographic results, and the initial disease and age may adversely affect the outcomes.

Type III acetabular defect revision with bilobed components: five-year results

Combined segmental and cavitary deficiencies of the acetabulum (American Academy of Orthopaedic Surgeons Type III) are a difficult problem that revision arthroplasty surgeons must tackle with increasing frequency. Porous-coated bilobed acetabular components are a reconstruction option that allows for increased host bone-prosthesis contact with restoration of the anatomic hip center without the use of a structural bone graft. Eleven consecutive Type III acetabular defects in 11 patients were revised with a porous-coated bilobed cup without a structural bone graft between January 1999 and January 2001 and prospectively followed. Average Harris hip scores improved from 36 preoperatively to 85 postoperatively. Radiographic analysis showed improvement in the average vertical displacement of the hip center. Average leg length discrepancies decreased from 34 mm preoperatively to 7 mm postoperatively. There have been no revisions performed or planned. Porous-coated bilobed acetabular components can provide good clinical and radiographic results at intermediate followup for treatment of Type III acetabular deficiencies. Bilobed components offer a viable option for reconstruction of Type III defects without the use of a structural bone graft or cement while maximizing the host bone-implant contact and restoring the native hip center.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Treatment options and allograft use in revision total hip arthroplasty the acetabulum

One of the most challenging aspects of revision total hip arthroplasty is management of bone loss. The acetabulum is particularly difficult, with its complex morphology and proximity to major neurovascular structures. We present a reliable classification system of pelvic and acetabular bone loss based on preoperative radiographs, and this classification system directs treatment of bone loss. The type and application of allograft bone required for the reconstruction will be reviewed for each level of bone loss. Good ability to prognosticate each level of treatment is available from follow-up studies based on survival. We know of no other scientifically developed and validated classification of pelvic bone loss that predicts the likely success of the applied treatment.

Burch-Schneider cage fracture: a case report

In this report, we present the case of a 64-year-old woman who sustained a Burch-Schneider cage fracture. Prior to this event, she underwent repeated acetabular reconstructions, but in the end prosthesis removal was performed as a salvage procedure. We believe that the primary cause of the fracture was metal fatigue facilitated by intraoperative re-contouring of the flange, as well as reuse of the cage. Based on this case we caution against repetitive or excessive flange bending during implantation of Burch-Schneider cages and do not recommend their reuse.

Fatigue failure of the GAP ring

This study reports the results and early failures using the Graft Augmentation Prosthesis ring in the reconstruction of acetabular defects encountered during total hip arthroplasty. Seventeen consecutive Graft Augmentation Prosthesis rings were used during 7 complex primary and 10 revision hip arthroplasties. Five patients died during the follow-up period. Of the remaining 12 patients, 7 had been revised at an average of 5 years follow-up. Five cases were revised because of fatigue failure of the implant associated with allograft resorption. Two cases were revised for recurrent dislocations. Because of this high mechanical failure rate (5 of 12 cases at only 5 years follow-up), we have abandoned this device in favor of implants with more mechanical strength.

Repair of bone defects in revision hip arthroplasty by implantation of a new bone-inducing material comprised of recombinant human BMP-2, Beta-TCP powder, and a biodegradable polymer: an experimental study in dogs

A recombinant BMP-2-retaining putty-form implant in combination with a hip prosthesis was used to reconstruct a canine hip joint with defects similar to those encountered in revision total hip arthroplasty (THA). The bone defects were made by resecting the medial half of the proximal femur and the superior acetabular bone with inner iliac wall perforation in 10 dogs. In five dogs, hip prostheses were implanted with the putty material consisting of a synthetic polymer (poly D,L-lactic acid-polyethylene glycol block copolymer), beta-tricalcium phosphate powder, and recombinant human BMP-2 in each defect (BMP/Polymer/TCP group). In the remaining five dogs, the same material without rhBMP-2 (control group) was implanted. In the BMP/Polymer/TCP group, new radiopaque shadows began to appear 4 weeks after surgery at the defects around the hip prostheses on both the femoral and acetabular sides. At 12 weeks, the defects were completely filled with new bone in contact with the prosthesis. On histology, the rhBMP-2/Polymer/beta-TCP composite putty implants had been completely resorbed and replaced by new bone. Repair of the bone defects was not seen in the control group. The ability of this material to restore bone effectively eliminates the dependency on bone grafts of autogeneic or allogeneic origin for revision hip arthroplasty and thus opens up a potential new treatment approach in hip cases requiring this type of surgery.

[Acetabular revision for aseptic loosening in total hip arthroplasty using cementless cup and impacted morselized allograft]

PURPOSE OF THE STUDY

Impaction grafting can be used in cementless fixation with morsellized bone, bone graft, and hemispherical cup. The first goal of impaction grafting in revision of total hip arthroplasty is to transform segmental defects into cavitary defects and obtain a full compaction of the graft in order to restore the bone stock. The second goal is to achieve primary stability of the cup. The third goal is to restore the hip center of rotation with a cup anatomically located in the acetabulum. The aim of our study was to evaluate the results of a surgical technique with impacted morsellized bone graft and a cementless press-fit cup for the revision with defect type III according to the AAOS classification.

MATERIAL AND METHODS

We performed a retrospective study including 34 hip reconstructions during revision of acetabular aseptic loosening with type III AAOS acetabular defects. All the revisions were performed in the same center by two senior surgeons. Mean age at surgery was 58 years. There were 23 women and 11 men. All reconstructions were performed with a cementless cup and a morsellized impacted bone graft. The analysis of the acetabular defects was done preoperatively according to the AAOS classification. We analyzed postoperatively and at follow-up: position and stability of the acetabular cup, restoration of the hip center and graft integration.

RESULTS

Mean follow-up was 6.6 years (range 3-13 years). Complications included three dislocations, two trochaanteric nonunions. Two acetabular components were revised for septic loosening. According to the Kaplan-Meier survival curves, with endpoint criteria defined as acetabular cup removal, survival was 91.3% at 10 years (95CI: 86.3-96.3). The preoperative Harris hip score was 53 points (range 26-86) and at last follow-up 94 (47-100). Concerning the subjective clinical outcome, 96% of patients were satisfied or very satisfied at last follow-up. 100% of cups were considered stable at follow-up and bone integration was good in 100%. The center of rotation was located in anatomic position mediolaterally in 66% and in the craniopodal plane in 44%.

DISCUSSION

Restoration of bone stock is one of the main goals during hip reconstruction after aseptic loosening. Clinical experience in our series has shown the reliability of the impacted morsellized bone graft allowing relocation of the center of rotation and good cup stability. Biological fixation of the cup and graft integration seems good at mid-term follow-up. The cup that we used in our series combined the advantages of a press-fit cup and those of a reinforcement ring. The combination of this type of cup with morsellized bone graft seems to be a reliable solution for restoring bone stock, relocating the hip center, and stabilizing the cup in revision total hip arthroplasty with type III acetabular defect according to the AAOS classification.

Cementless hemispheric hydroxyapatite-coated sockets for acetabular revision

This study describes our experience with a hydroxyapatite-coated uncemented hemispherical component used for revision of 72 patients with aseptic loosening of the acetabular component. Preoperative Paprosky classification of the acetabular defects was 1 type I, 35 type II, and 36 type III; according to American Academy of Orthopaedic Surgeons, 14 segmental, 10 cavitary, and 48 combined. The mean follow-up was 7.6 years (range, 5.0-13.0). Complications were seen in 7 cases (9.6%). Seventy acetabular components (97.2%) showed bone ongrowth on the radiographs. The survival rate was 90.8% after a mean follow-up of 7.6 years (range, 5.0-13.0) when revision for any reason is the end point (confidence interval, 80.5%-100%) and 98.1% (confidence interval, 94.5%-100%) when aseptic loosening of the cup is the end point. We conclude that hydroxyapatite-coated cups for acetabular revision show promising results.

Acetabular revisions using a cementless oblong cup: five to ten year results

The purpose of this paper was to evaluate the results of acetabular revisions with the use of an oblong revision cup that is designed with its longitudinal diameter elongated relative to its transverse diameter. Between 1996 and 2001, 62 hips in 60 patients underwent an acetabular revision with the insertion of a LOR acetabular component. Seven hips were lost to follow-up or the patients died; the remaining 55 hips (53 patients) remained in follow-up for an average of 7.2 years (range: 5.0-10.1 years). One socket was revised for aseptic loosening, and another was operated on for a late polyethylene liner dissociation. The average Harris hip score (HHS) improved from 34 to 79. Results were rated as excellent in 16 hips, good in 28, fair in six and poor in three. Radiographic analysis demonstrated an improvement in the average vertical displacement of the hip centre: 49 hips had a well-fixed, bone-ingrown cup and four had a stable fibrous union. For large superolateral acetabular bone deficiencies, this implant facilitated a complex reconstruction without the need for bulk structural acetabular bone grafts, provided good clinical results and showed satisfactory stability at the midterm follow-up.

Long-term results of 58 hip cup revision arthroplasties using a threaded ring implant

INTRODUCTION

There is still a discussion whether cementless hip cup revisions should be performed with a press fit cup or a threaded ring implant.

MATERIALS AND METHODS

The results of 58 hip cup changes using the spherical, threaded ring "Munich" are presented. In 16 cases, the ring "Munich I" with a smooth surface and in 42 cases the ring "Munich II" with a corundum-blasted surface were implanted. Mean follow-up was 7.5 years; radiological signs of loosening and the Harris Hip Score were examined.

RESULTS

The re-revision rate for aseptic loosening of the ring was 12/58 overall (Munich I: 5/16, Munich II: 7/42). The average Harris Hip Score was 76.2 overall (Munich I: 74.4, Munich II: 76.8). Higher survival rates were achieved with the "Munich II" ring due to improved construction details.

CONCLUSION

These rates are still below those reported for press-fit cups, the technique described by Slooff or reinforcement rings.

An integrated solution to acetabular revision surgery

The three salient reasons for failure of acetabular revision surgery have been failure of fixation, wear and lysis, and dislocation. This review focuses on the major progress made in addressing these three items, leading to an overall approach integrating three contemporary techniques with a strong likelihood of improving acetabular revision surgery. These three techniques are the use of hemispheric cementless acetabular components, alternate bearings, and big heads.

Impaction bone grafting for revision hip arthroplasty: biology and clinical applications

Impaction bone grafting techniques are useful when the orthopaedic surgeon is faced with large cavitary acetabular defects or a large ectatic femoral metaphysis or diaphysis. Impaction bone grafting of the acetabulum involves packing of cavitary defects with compressed particulate graft, followed by insertion of either a cemented or cementless acetabular component. Impaction grafting of the femur involves retrograde filling of the femoral canal with impacted particulate graft, creating a neomedullary canal into which a cemented femoral stem can be placed. Use of the impaction allografting technique is appealing, especially in young patients, because of its potential to restore bone stock. The technically demanding nature of the procedure, the risk of complications, and the unknown long-term fate of the impacted allograft highlight the need for ongoing assessment of this technique for revision total hip arthroplasties.

Acetabular revision with morsellised allogenic bone graft and a cemented metal-backed component

Failure of total hip arthroplasty with acetabular deficiency occurred in 55 patients (60 hips) and was treated with acetabular revision using morsellised allograft and a cemented metal-backed component. A total of 50 patients (55 hips) were available for clinical and radiological evaluation at a mean follow-up of 5.8 years (3 to 9.5). No hip required further revision of the acetabular component because of aseptic loosening.

All the hips except one had complete incorporation of the allograft demonstrated on the radiographs. A complete radiolucent line of > 1 mm was noted in two hips post-operatively. A good to excellent result occurred in 50 hips (91%). With radiological evidence of aseptic loosening of the acetabular component as the end-point, the survivorship at a mean of 5.8 years after surgery was 96.4%.

The use of impacted allograft chips in combination with a cemented metal-backed acetabular component and screw fixation can achieve good medium-term results in patients with acetabular bone deficiency.

Early postoperative transverse pelvic fracture: a new complication related to revision arthroplasty with an uncemented cup

BACKGROUND

Uncemented hemispherical cups are commonly used to revise failed acetabular total hip components, even in the presence of marked acetabular bone loss. The purpose of the present study was to report a new complication of acetabular component revision with an uncemented hemispherical cup.

METHODS

We retrospectively reviewed the records of seven patients (seven hips) in whom an early postoperative transverse acetabular fracture had developed following the implantation of an uncemented trabecular metal cup for the revision of a failed acetabular component. All patients were female. The average age was 63.6 years. The reason for acetabular revision was aseptic loosening of the original cup in five patients and reimplantation after a previous resection arthroplasty in the remaining two. The average cup size used for revision was 58 mm. In two hips, additional modular acetabular metal augments were used to restore the acetabular rim.

RESULTS

The average postoperative time to diagnosis of a transverse acetabular fracture was eight months. Five of the seven patients presented with a marked acute increase in pain and a new displaced transverse acetabular fracture (pelvic discontinuity) that was visible on plain radiographs. Two patients were asymptomatic but had a nondisplaced transverse acetabular fracture. In all seven patients, the trabecular metal socket appeared radiographically to be well fixed to part of the pelvis. The five patients with a displaced fracture were managed with additional surgery to stabilize the fracture.

CONCLUSIONS

To our knowledge, early postoperative transverse pelvic fractures following revision of the acetabular component have not been reported previously. The most likely causes of this complication are further weakening of the remaining pelvic bone stock as a result of the reaming required to obtain a secure fit of a large-diameter hemispherical socket and the cyclic stresses on the weakened bone with resumption of walking. It is unlikely that the fractures occurred intraoperatively because in each case the socket remained well fixed to one of the pelvic fragments.

Acetabular reconstruction in revision hip surgery using femoral head block allograft

This prospective study analyzed the clinical and radiological results of 140 consecutive cases of acetabular revision using large frozen femoral head allografts and cemented all-polyethylene acetabular components. Mean follow-up was 10 years (range: 5-16 years). Thirty patients died, seven were lost to follow-up, and 26 had failed and undergone further surgery. Nineteen failures were due to aseptic failure and collapse of the graft. Kaplan-Meier survival analysis calculated a mean survival at 10 years of 88.5% for revision for any reason. We compared all reported techniques of acetabular reconstruction for similar defects and recommend a surgical strategy based on the available evidence, but weighted towards a preference to reconstitute bone stock rather than removing further bone in the revision situation.

Management of acetabular bone stock deficiency

Acetabular bone stock deficiency in primary and revision total hip arthroplasties can usually be effectively managed by combining the use of appropriately designed implants and structural or nonstructural bone grafts or bone graft substitutes. An appreciation of the deformity before surgery will allow for proper planning and execution of a plan at the time of surgery. The presence of segmental defects or pelvic instability is particularly important to assess preoperatively. Adherence to basic principles of bone grafting and implant fixation allows surgeons to reliably manage these potentially difficult problems.

Structural allograft and primary press-fit cup for severe acetabular deficiency. A minimum 6-year follow-up study

Between October 1992 and December 1996, 23 patients with pelvic bone stock deficiency involving major columns underwent revision surgery with a cementless press-fit cup and a structural bone graft. Twenty cases were followed up for a minimum of 6 (average 7.6, range 6-11) years. Three cups were revised: one for aseptic loosening, one for septic loosening, and one for recurrent dislocation. At latest follow-up, the average Merle d'Aubigne hip score improved from 10.9 to 16.2; four hips were rated excellent, seven very good, three good, two fair, and one poor. All cups were stable; the grafts were integrated and anatomy was restored. The Kaplan-Meier cumulative probability of not having revision for loosening at 11 years, predicted a survival rate of 84.4%. We are confident that these results are satisfactory for a very demanding procedure.

Use of custom triflanged acetabular components in revision total hip arthroplasty

Difficulty persists in consistently treating massive acetabular defects in revision total hip arthroplasty. A relatively new treatment option for these complex cases is a custom triflanged acetabular component created from anatomic data derived from a computed tomography scan of the pelvis. The custom triflanged acetabular component achieves fixation on the remaining ilium, ischium, and pubis with multiple fixation screws while the acetabular defect is filled with cancellous allograft bone. A retrospective review was done of 26 hips (26 patients) with massive periacetabular bone loss (Paprosky Type 3B) reconstructed with a custom triflanged acetabular component. Twenty-three of 26 patients (88.5%) were considered clinically successful at short-term followup (average, 54 months; range, 24 to 85 months), with stable fixation and reconstruction of periacetabular bone. Three failures occurred from loss of ischial fixation in two patients with a preoperative pelvic discontinuity and one patient with severe osteopenia. These devices should be used with caution in patients with a preoperative pelvic discontinuity unless additional column plating is done.

Modular porous metal augments for treatment of severe acetabular bone loss during revision hip arthroplasty

Modular acetabular augments were implanted in 16 patients (16 hips) for support of an uncemented hemispheric acetabular component during revision acetabular reconstruction. Based on the classification of Paprosky, acetabular bone defects were classified as 2A in one hip, 2B in three hips, 2C in one hip, 3A in five hips, and 3B in six hips. Preoperatively, the prosthetic femoral head centers were located at a mean horizontal distance of 18.6 mm (range, -3-46 mm), and a mean vertical distance of 27.6 mm (range, -16-52 mm) from the approximate femoral head center. Postoperatively, the prosthetic femoral head centers were located at a mean horizontal distance of 10.4 mm (range, 1-25 mm), and a mean vertical distance of 7.4 mm (range, -15-25 mm). At final followup, no implant had evidence of migration or loosening. At early clinical followup, this modular acetabular augment system seems helpful in acetabular reconstructions that cannot be treated with an uncemented hemispheric cup that would have required other forms of treatment such as structural allografts, acetabular cages, bilobed acetabular components, or custom acetabular components. Longer term followup is required to determine whether there are untoward effects of using a modular acetabular reconstructive system.

Acetabular revision with a modular anti-protrusio acetabular component

Current anti-protrusio cages are non-porous-coated and 1 piece and they require liner cementation. These factors limit bone ingrowth, trials, and modularity. Results of a completely modular porous-coated anti-protrusio component (MAPC) are presented. Sixty-three acetabular revisions with MAPC were performed from 1998-2001 by 2 surgeons. Average follow-up was 29 months (range, 24-50). 30/63 (48%) had Paprosky type 3A or B defects. 55/63 (87%) MAPCs remain in place. Four components were removed for infection, 3 for loosening, and 1 for malposition. Eight hips dislocated, requiring 6 reoperations. Two MAPCs are radiographically loose but asymptomatic. At short-term follow-up, these results are comparable to conventional 1-piece anti-protrusio cages. Advantages include the potential for bone ingrowth and long-term fixation, surgical technique similar to large hemispherical components, ability to trial, and modularity.

The use of bilobed porous-coated acetabular components without structural bone graft for type III acetabular defects in revision total hip arthroplasty: a prospective study with a minimum 2-year follow-up

A prospective analysis was undertaken of 11 hips (in 11 patients) that underwent revision acetabuloplasties with bilobed, porous-coated, acetabular implants without the use of structural bone graft for type III acetabular defects. The average patient age was 66.3 years, with an average follow-up of 38 months (range, 24-49 months). No acetabular components required or are pending revision surgery. Average pain and hip scores improved from 8 and 36 preoperatively to 42 and 89 postoperatively, respectively. Average leg-length differences decreased from 34 mm preoperatively to 7 mm postoperatively. The use of bilobed acetabular components without structural bone graft is a feasible alternative for reconstructing type III acetabular defects, and can provide good short-term clinical results, while reconstructing the hip center and maximizing host-implant contact.

The Levine anterior approach for total hip replacement as the treatment for an acute acetabular fracture

The treatment of acetabular fractures in part relies on the selection of a specific surgical approach that allows for accurate reduction of fracture fragments. Moreover, these acetabular approaches were not developed for the insertion of a total hip replacement. Therefore, if a total hip arthroplasty is to be the treatment of an acute acetabular fracture, a single incision that permits reduction of the acetabular fracture fragments and ease of insertion of the arthroplasty components would be desirable. The Levine anterior approach provides both accesses to the anterior wall/column for reduction and fixation and to the femoral shaft for insertion of a total hip replacement. This paper describes that surgical technique and our initial clinical experience with this approach for acute acetabular fractures. A consecutive group of 10 patients with acetabular fractures, all involving the anterior wall/column with articular impaction (>50% of the acetabular roof) including 2 cases with an associated posterior hemitrans-verse component, were reviewed. After fracture reduction and fixation, a hybrid total hip replacement was implanted in all cases with an average acetabular component size of 56 mm (range 52-64). At a mean follow-up of 36 months (range 24-53), all fractures united, and all acetabular components remained fixed with no evidence of migration or loosening. There were 2 complications, a Brooker grade II heterotopic ossification and 1 postoperative anterior dislocation treated successfully with closed reduction and spica cast immobilization. The average Merle d'Aubigné hip score at latest follow-up was 16 (range 13-18). The Levine anterior approach is a reliable, safe, and efficient technique that permits early mobilization of patients with anterior wall/column acetabular fractures requiring a total hip replacement.

Jumbo cup or high hip center: is bigger better?

A jumbo cup and a high hip center cup placement are 2 options in the revision of loose acetabular components associated with bone loss. They allow biologic attachment, which is required for long-term fixation. They are easier to use than cages. In my personal series of 564 acetabular revisions from 1986 to 2001, standard-size porous cups with a high hip center were used in 42 (7%) of the cases. Jumbo cups were used in 166 (29%) of the cases. Nineteen percent of the jumbo cups also were placed at a high hip center. The majority of these cups were placed into combined segmental and cavitary defects. The average follow-up was 6.1 years. One jumbo cup and 1 high hip center standard cup were revised for aseptic loosening (1%). The 5-year and 10-year survival rates for shell revision were 95% and 87%, respectively.

Cementing a liner into a stable cementless acetabular shell: the double-socket technique

BACKGROUND

During revision hip replacement surgery, the cementless acetabular shell is often well fixed but the locking mechanism may be ineffective. Cementing a new liner into the existing acetabular shell (the double-socket technique) can provide a simple solution. The purposes of the present study were to review our initial clinical results and to define the potential limitations of this technique.

METHODS

Thirty-two hips with a preexisting well-fixed acetabular socket that had been in situ for an average of 8.6 years were treated with the insertion of a new polyethylene liner (seventeen hips) or a metal liner (fifteen hips) with use of cement. The indication for this technique was a deficient locking mechanism in twenty-two hips and the unavailability of a matching liner in ten hips. Anteroposterior radiographs of all hips were analyzed by a single independent reviewer.

RESULTS

The mean duration of follow-up was 5.1 years. Six hips required a reoperation after a mean of 29.7 months; the reasons for the reoperations included aseptic failure of the acetabular construct (four hips), instability (one hip), and sepsis (one hip). The University of California at Los Angeles hip scores improved significantly (p < 0.001) compared with the preoperative values; specifically, the mean score improved from 6.2 to 9.1 for pain, from 6.3 to 8.3 for walking, from 6.2 to 7.8 for function, and from 4.7 to 5.8 for activity. The prevalence of dislocation was 22%. Kaplan-Meier analysis with revision as the end point revealed a five-year survival rate of 78% (95% confidence interval, 55% to 91%).

CONCLUSIONS

The double-socket technique is a good alternative to acetabular socket removal for suitable candidates who have a well-fixed cementless socket with an inner diameter that is larger than the outer diameter of the cemented liner. This technique preserves acetabular bone stock and permits conversion to alternate bearing surfaces. We believe, however, that removal of a well-fixed acetabular shell or the use of a constrained liner should be strongly considered for patients with a history of hip instability.

Use of structural allografts in acetabular revision surgery

Bone loss is a challenging problem with complex acetabular revisions. With an adequate biologic and mechanical environment, uncemented hemispheric component reconstructions have provided long-term durable results for acetabular revisions. Decisions about reconstructive options can be made with the aid of a classification system that addresses the location and severity of bone loss as it relates to achieving the prerequisites for biologic fixation with a hemispheric component. Structural allograft may be used to provide a mechanical environment that supports host bone ingrowth into an acetabular component. Alternatively, structural allograft may allow restoration of joint mechanics in situations where host bone loss precluded biologic fixation. We describe the indications and technique for the use of structural allograft in revision acetabular surgery.

Cementless acetabular reconstruction in revision total hip arthroplasty

Reconstruction of the failed acetabular component in total hip arthroplasty (THA) can be challenging. Although there are multiple reconstructive options available, a cementless acetabular component inserted with screws has been shown to have good intermediate-term results and is the reconstructive method of choice for the majority of acetabular revisions. We reviewed the results of 138 consecutive acetabular revisions done with a hemispheric, cementless acetabular component that is sintered with Ti fiber metal mesh and was inserted with line-to-line reaming and multiple screws for fixation. At a mean of 15 years, 19 acetabular components had been revised (13.8%); seven were revised for recurrent instability, six were revised for deep periprosthetic infection, five well-fixed cups were removed at the time of femoral revision, and one cup was fixed by fibrous tissue only at the time of femoral revision and was removed. One acetabular component was radiographically loose. Survivorship of the component was 81% at 15 years when revision for any reason was considered as an end point and 96% when revision for loosening or radiographic evidence of loosening was considered as a second end point. Cementless acetabular revision provides durable results at 15 years with a low rate of failure for loosening.

Factors influencing the longer-term survival of uncemented acetabular components used in total hip revisions

BACKGROUND

There are few longer-term follow-up reports of the results and complications of the use of cementless acetabular components in revision hip arthroplasty. In this study, we analyzed the clinical and radiographic results to determine the factors that affect longer-term survival of titanium-fiber-metal-coated acetabular components.

METHODS

During a fourteen-year period, one surgeon performed 211 consecutive unselected cementless acetabular revisions in 194 patients with a mean age of sixty-two years. The same technique was used for all revisions: the component was impacted and was fixed with multiple screws, and bone deficiencies were augmented with supplemental bone graft. Both the acetabular and the femoral components were revised in 142 hips, whereas an isolated acetabular revision was performed in sixty-nine hips. All 211 revisions were included in a survivorship analysis to twelve years. Prospectively determined clinical results in 135 hips and radiographic results in 131 hips were available at a minimum of five years postoperatively.

RESULTS

Seven acetabular components were removed: three, because of infection; one, because of recurrent dislocation; and three, because of mechanical loosening. There was asymptomatic radiographic loosening of one additional acetabular component, for a total rate of aseptic loosening of 2%. The twelve-year prosthetic survival rate was 95% (95% confidence interval, 91% to 99%), with failure defined as component removal for any reason. There was no significant difference in the rate of survival of the cup or femoral component between the sixty-nine hips treated with isolated acetabular revision and the 142 hips in which both components were revised. There was a significant difference in the rate of dislocation between the hips treated with isolated acetabular revision (dislocation in fourteen hips, 20%) and those in which both components had been revised (dislocation in eleven hips, 8%; p = 0.03), but there was no difference in component survival if a dislocation occurred. There was a significant association between a patient weight of >82 kg and acetabular failure (p = 0.04).

CONCLUSIONS

This titanium-fiber-metal-coated hemispheric component fixed with multiple screws had a twelve-year survival rate of 95% when used in an unselected, consecutive series of acetabular revisions. The rate of dislocation was significantly higher in the patients treated with isolated acetabular revision, and routine postoperative bracing is now recommended for that group.

Fate of cementless acetabular components retained during revision total hip arthroplasty

BACKGROUND

Removal of a well-fixed cementless acetabular component can result in increased operative time and postoperative morbidity. The objectives of this retrospective study were to determine whether retention of a well-fixed acetabular component at the time of isolated femoral revision was compatible with long-term socket survival.

METHODS

The records of eighty-three consecutive patients (ninety hips) in whom a well-fixed cementless socket had been retained during revision of a femoral component were reviewed. The mean age of the patients was 48.7 years at the time of the primary arthroplasty and 54.1 years at the time of femoral revision. The radiographic analysis was based on anteroposterior radiographs and was performed by a single independent reviewer. The intraoperative criterion for stability of the socket was the absence of movement at the bone-implant interface during the application of direct pressure to the edges of the socket in four quadrants with use of a metallic pusher.

RESULTS

At the time of the isolated femoral revision, no socket demonstrated a radiolucent line measuring >1 mm in any two zones and forty of the ninety hips had periacetabular osteolysis. The mean size of the osteolytic lesions was 5.71 cm(2) (range, 0.4 to 24.2 cm(2)), and twenty-eight of the forty hips underwent bone-grafting. The mean duration of follow-up was 9.7 years after the isolated femoral revision and 14.9 years after the primary arthroplasty. Five acetabular sockets were revised at a mean of 6.8 years after the femoral revision. Only one of these sockets had failed because of aseptic loosening. With revision of the acetabular component for any reason as the end point, the survival rate was 98.7% at five years and 93.5% at ten years after the femoral revision and 100% at ten years and 93.9% at fifteen years after the primary arthroplasty. No hip showed recurrence or expansion of periacetabular osteolysis. The prevalence of dislocation was 16% (fourteen of ninety).

CONCLUSIONS

Revision of a stable, cementless acetabular component solely on the basis of its duration in vivo or the presence of periacetabular osteolysis does not appear to be warranted. Retention of the socket with grafting of larger periacetabular osteolytic lesions appears to be consistent with satisfactory socket longevity.

Dislocation after polyethylene liner exchange in total hip arthroplasty

Little has been published on the outcomes of polyethylene liner exchanges for wear or osteolysis. We assessed 24 patients from our clinic who had an isolated polyethylene liner exchange for wear or osteolysis with retention of the acetabular shell and femoral stem. At a mean 56-month follow-up time, 6 hips (25%) had dislocated. Of these, 2 underwent repeat surgery for recurrent dislocation; 1 had 3 dislocations; 1 had 2 dislocations; and 2 had single dislocations. Seventeen of the remaining patients answered our questionnaire: 13 recovered faster from the polyethylene liner exchange than from the primary arthroplasty; 4 believed that their hips were not as stable, 4 believed the hip did not function as well; and 1 underwent revision for cup loosening. We conclude that polyethylene liner exchanges, with or without femoral head exchange for wear or osteolysis, are associated with a high risk of dislocation and possible decrease in function.

Acetabular revision without cement

We reviewed the clinical and radiologic results of 47 cementless acetabular revisions performed by a single surgeon. The mean follow-up period was 58 months. The American Academy of Orthopaedic Surgeons (AAOS) acetabular defect classification was type I in 4 hips, type II in 9 hips, and type III in 32 hips. All patients received AML (Depuy, Warsaw, IN) Duraloc cup implants. Morcellized allograft was used in 23 hips (49%), and screw augmentation in 22 hips (47%). The Harris Hip score improved from 72 to 90 points. No revisions were performed for aseptic loosening. Nonprogressive thin radiolucent lines were found in a single zone in 10 hips (21%) and in all 3 zones in 5 hips (11%). No migration was found in any cups with radiolucent lines, and the presence of a radiolucent line was considered clinically unimportant. Progressive loosening with migration of the cup was found in 1 hip (2%). Kaplan-Meier survivorship using revision for aseptic loosening or radiologic loosening as end points was 92% at 72 months. No statistically significant difference was found in the survival of the cups fixed with or without screws. These encouraging midterm results confirm the role of cementless acetabular revision.

Cementless acetabular components: the gold standard for socket revision

Hemispherical ingrowth sockets are used for acetabular revision in over 90% of cases. Multiple experiences now show the success of this technique in both consecutive series and specific settings. In addition to understanding the technique required to implant these components successfully, the surgeon must be aware of the settings in which the construct is not likely to work and plan for alternative techniques when needed.

Management of massive acetabular defects in revision total hip arthroplasty

Twenty-four cases of massive periacetabular bone loss (Paprosky Type 3B) were reconstructed using custom triflanged acetabular components (CTAC). Fixation is obtained by the creation of a triflanged component that is anchored to the ilium, ishium, and pubis with multiple fixation screws. Acetabular defects are grafted with large amounts of cancellous allograft. Modular polyethylene liners are then locked into the CTAC. Twenty-one of 24 cases (87.5%) were considered clinically successful at short-term follow-up (average, 48 months; maximum, 78 months), with stable fixation and reconstruction of periacetabular bone. Three failures occurred from loss of fixation in patients with a preoperative dissociation of the hemipelvis and severe osteopenia. Presently, these devices should be used with caution in cases with a preoperative dissociation of the hemipelvis, unless additional column plating is performed.

Extra-large press-fit cups without screws for acetabular revision

This retrospective study reports the 4- to 6-year results of clinical and radiologic follow-up of 60 acetabular revisions using extra-large hemispherical press-fit cups without additional screw fixation. Bone grafts were used in 17 cases. One cup loosened and required re-revision after 12 months. Initial migration was noted in 6 cases, but showed no progression after less than 2 years. In 2 hips that were revised for deep infection, the cups were found incorporated. At final follow-up, 57 hips (95%) were found firmly fixed radiologically. The Harris Hip score improved from a mean of 58.7 points preoperatively to 90.6 points. Provided a high friction coefficient is present, extra-large hemispherical cups offer sufficient stability even in severe cases. Most do not require additional screw fixation.

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.

Acetabular components without bulk bone graft in revision surgery: A 5- to 13-year follow-up study

Eighty-three consecutive revisions in 74 patients using a porous-coated acetabular component without bulk bone graft were followed up for an average of 9.3 years (range, 5-13 years). A large-diameter cup was implanted in hips with adequate osseous support, and a high hip center technique using a standard- or smaller-diameter cup was selected in hips without sufficient bone stock. Acetabular bone deficiency was segmental in 18 hips, cavitary in 30, and combined segmental and cavitary in 35. Four (5%) cups were revised again; 1 for infection, 1 for dislodgement of the polyethylene liner from the metal shell, and 2 for recurrent dislocation. No acetabular components were categorized as definitely loose at final follow-up. The current satisfactory results encourage the use of this simple technique.