Factors related to failure of structural bone grafts in acetabular reconstruction of total hip arthroplasty

Biphasic bone graft substitute in revision total hip arthroplasty with significant acetabular bone defects : a retrospective analysis

AIMS

Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects.

METHODS

We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures.

RESULTS

Mean follow-up was 39.5 months (36 to 71), with a significant improvement in post-revision function compared to preoperative function. Graft site remodelling was rated radiologically as moderate in 31 hips (63%) and strong in 12 hips (24%). There were no cases of complete graft site dissolution. No acetabular loosening was identified. None of the patients developed clinically significant heterotopic ossification. There were twelve reoperations: six patients developed post-revision infections, three experienced dislocations, two sustained periprosthetic femur fractures, and one subject had femoral component aseptic loosening.

CONCLUSION

Our series reports bone defect restoration with the sole use of a biphasic injectable BGS in the periacetabular region. We did not observe significant graft dissolution. We emphasize that successful graft site remodelling requires meticulous recipient site preparation.Cite this article: Bone Jt Open 2022;3(12):991-997.

Stepped osteotomy of femoral head autograft for acetabular reconstruction in total hip arthroplasty for dysplasia of the hip: 3 to 12 years' results

OBJECTIVES

This study aims to describe a stepped osteotomy technique applied to the femoral head autograft to keep the graft volume at a sufficient level, provide primary stability, and direct cancellous-cancellous bone contact.

PATIENTS AND METHODS

In this retrospective study, 24 hips of 20 patients (5 males, 15 females; mean age 53 years; range, 43 to 68 years) with dysplasia of the hip (DDH) who underwent total hip arthroplasty with femoral head stepped osteotomy technique were evaluated between April 2003 and June 2010. Patients' age, gender, operation side, and postoperative complications were recorded. Aseptic loosening of the acetabular cup and graft integration/resorption were evaluated radiographically. Radiological evaluations were performed according to the methods of DeLee and Charnley, and Mulroy and Harris. Functional status of the patients was determined according to the criteria of Merle d'Aubigné and Postel, and Harris hip score (HHS).

RESULTS

The mean follow-up period was 5.5 years (range, 3 to 12 years). None of the patients had any complications in the early postoperative period. In all patients, the percentage of acetabular component coverage by the graft was measured as 27% (range, 19 to 38%) on average. At the last follow-up, all patients were satisfied with the result and there was no sign of clinically loosening, osteointegration was complete, and there was no radiographic evidence of graft resorption or collapse of any hip. The overall Merle d'Aubigné scores and HHSs of the patients significantly improved at the final follow-up.

CONCLUSION

This stepped osteotomy technique increases the probability of osteointegration, reduces the need for early revision, and provides reliable stability with satisfactory clinical and radiological midterm results.

The Use of Porous Tantalum Augments for the Reconstruction of Acetabular Defect in Primary Total Hip Arthroplasty

BACKGROUND

Given the lack of studies of acetabular defect reconstruction in primary total hip arthroplasty (THA) using tantalum augments, this study aims to evaluate clinical and radiographic results for treatment with tantalum augments to reconstruct acetabular defects in primary THA.

METHODS

We retrospectively reviewed 19 patients (19 hips) with acetabular defects who underwent primary THA using tantalum augments, with a minimum follow-up of 2 years. Clinical, radiographic, and surgical data were retrospectively evaluated.

RESULTS

Mean follow-up was 5.1 years (range 2.5-7.6). Harris Hip Score improved from 35.8 (range 19-56) preoperatively to 85.3 (63-98) at last follow-up (P < .01). Oxford Hip Score, University of California Los Angeles activity scale, and Short Form-12 score also improved significantly from presurgery to last follow-up. Mean operation time and blood loss were 124.7 minutes and 530 mL, respectively. Mean hip center position was 2.97 cm (range 2.35-3.58) horizontally and 2.06 cm (1.29-2.92) vertically, and mean acetabular inclination was 38.9° (range 27°-47°) at last follow-up. These parameters were not significantly different from those recorded immediately postoperatively (P > .05). There was no aseptic loosening, cup and augment migration, screw breakage, or presence of hip infection at last follow-up. All hips were radiographically stable.

CONCLUSION

Porous tantalum augments combined with titanium shells lead to satisfactory clinical and radiographic outcomes for the reconstruction of acetabular defect in primary THA at a mean 5.1 years of follow-up. This approach confers anatomical cup placement, simple operation, and a high rate of stable fixation.

Acetabular Reconstruction With the Medial Protrusio Technique for Complex Primary and Revision Total Hip Arthroplasties

BACKGROUND

In the setting of acetabular deficiency during total hip arthroplasty (THA), the medial protrusio technique (MPT) allows for increased component coverage while avoiding excessive component abduction or elevation of the hip center. The technique involves controlled reaming through the medial acetabular wall while maintaining the continuity of the anterior and posterior columns. The purpose of this study is to analyze the results of the largest reported series to date of primary and revision THAs using the MPT.

METHODS

A retrospective review of THAs performed by a single surgeon from July 2004 to July 2010 identified 102 patients who underwent THA necessitating the use of the MPT (primary 86 and revision 16), with at least 2 years follow-up.

RESULTS

This study reports the largest series to date of primary and revision THAs using the MPT for acetabular deficiency. Postoperatively, mean Harris hip score was 86 (range 31-96). There was no correlation with degree of medialization and change in Harris hip score (P = .12). At mean follow-up of 41.1 months (range 24-92 months), there were no intrapelvic structure injuries and no acetabular components required revision. The MPT provided a safe and effective method for addressing acetabular deficiency and avoiding component malposition.

CONCLUSION

The MPT provided a safe and effective method for addressing acetabular deficiency in this large series of patients. The technique was successful at improving component coverage while maintaining an anatomic hip center and avoiding excessive component abduction. Fixation remained durable with no cases of loosening at final follow-up.

[Biological downsizing : Acetabular defect reconstruction in revision total hip arthroplasty]

BACKGROUND

Periacetabular bony defects remain a great challenge in revision total hip arthroplasty. After assessment and classification of the defect and selection of a suitable implant the primary stable fixation and sufficient biological reconstitution of a sustainable bone stock are essential for long term success in acetabular revision surgery. Biological defect reconstruction aims for the down-sizing of periacetabular defects for later revision surgeries.

TECHNIQUE

In the field of biological augmentation several methods are currently available. Autologous transplants feature a profound osseointegrative capacity. However, limitations such as volume restrictions and secondary complications at the donor site have to be considered. Structural allografts show little weight bearing potential in the long term and high failure rates. In clinical practice, the usage of spongious chips implanted via impaction bone grafting technique in combination with antiprotrusio cages for the management of contained defects have shown promising long time results. Nevertheless, when dealing with craniolateral acetabular and dorsal column defects, the additional implantation of macroporous metal implants or augments should be considered since biological augmentation has shown little clinical success in these particular cases.

PROSPECT

This article provides an overview of the current clinically available biological augmentation methods of peri-acetabular defects. Due to the limitations of autologous and allogeneic bone transplants in terms of size and availability, the emerging field of innovative implantable tissue engineering constructs gains interest and will also be discussed in this article.

Total hip arthroplasty with bulk femoral head autograft for acetabular reconstruction in developmental dysplasia of the hip

Developmental hip dysplasia (DDH) presents considerable technical challenges to the primary arthroplasty surgeon. Autogenous bulk grafting using the femoral head has been utilised to achieve anatomic cup placement and superolateral bone coverage in these patients, but reported outcomes on this technique have been mixed with the lack of graft integration and subsequent collapse, an early cause of failures. We describe a novel technique combining the use of bulk autograft with an iliac osteotomy, which provides primary stability and direct cancellous-cancellous bone contact, optimising the environment for early osseointegration. Twenty-one hips in 21 patients with DDH underwent this technique and were followed for a mean of 8.1 years. The preoperative radiographic classification was Crowe type I in 12 hips (57%), type II in 4 hips, and type III in 5 hips, and the mean Sharp angle was 49.6° (range 42°–60°). All grafts united by year. At time of followup, there was no radiographic evidence of graft collapse or loosening. There were no reoperations. Our study has shown that this technique variation combining an iliac osteotomy with bulk autograft in cases of developmental hip dysplasia provides early stability and reliable graft incorporation, together with satisfactory clinical and radiological outcomes in the medium term. Longer term study is necessary to confirm the clinical success of this procedure.

[Acetabular defect reconstruction in revision surgery of the hip. Autologous, homologous or metal?]

The treatment of periprosthetic bone defects of the acetabulum is a therapeutic challenge in hip revision surgery. The aims are the biological reconstruction of osseous acetabular defects and the restoration of a load-bearing acetabular bone stock as well as restoring the physiological joint biomechanics and achieving primary and load-stable fixation of the revision graft in the vital pelvic bone. The biological reconstruction of the acetabular bone stock should include what is referred to as "down-grading" of the acetabular defect situation in case a repeat revision procedure becomes necessary.Nowadays, a large variety of grafts and reconstruction procedures are available for the reconstruction of acetabular defects. The choice of suitable materials (osseous or metallic) for the restoration of a load-bearing acetabular bone stock is currently the subject of controversial discussion.This article reviews the various options for the reconstruction of acetabular bone defects taking into consideration the current findings in the scientific literature.

The use of structural periacetabular allografts in acetabular revision surgery: 2.5-5 years follow-up

INTRODUCTION

"Acetabular bone loss" presents a major reconstructive challenge in total hip arthroplasty. Loss of acetabular bone stock is a consequence of removal of bone during the original procedure, subsequent prosthetic failure and osteolysis resulting from wear particles of cement and polyethylene. In case of severe bone loss treatment options are rather limited, as fixation requires either biological (cancellous allograft with cage or structural allograft) or non-biological (trabecular metal, triflange implant, etc.) scaffolds.

MATERIALS AND METHODS

Fourteen acetabular revisions with a cemented cup, supported by a deep frozen structural periacetabular allograft without using a reinforcement ring or an antiprotrusio cage were performed. Clinical assessment was done using a Harris hip score. Graft resorption was radiographically quantified using a digital measurement program.

RESULTS

Kaplan-Meier survivorship was 67.1% at 42 months. After a mean follow-up of 3.6 years, 9 out of 14 patients had good clinical results. Mean resorption of 17.1% in six out of ten patients was observed. No sound evidence for union was found in nine out of ten patients. In the four re-revised patients, no bone stock restoration was found.

CONCLUSION

The bicortical allograft without protective device seems to function as a passive biocompatible dead scaffold, which has a less intrinsic strength at intermediate term follow-up, compared to the by ring or cage protected structural allografts.

The survival of support rings in complex acetabular revision surgery

Between 1980 and 2000, 63 support rings were used in the management of acetabular deficiency in a series of 60 patients, with a mean follow-up of 8.75 years (2 months to 23.8 years). There was a minimum five-year follow-up for successful reconstructions. The indication for revision surgery was aseptic loosening in 30 cases and infection in 33. All cases were Paprosky III defects; IIIA in 33 patients (52.4%) and IIIB in 30 (47.6%), including four with pelvic dissociation. A total of 26 patients (43.3%) have died since surgery, and 34 (56.7%) remain under clinical review. With acetabular revision for infection or aseptic loosening as the definition of failure, we report success in 53 (84%) of the reconstructions. A total of 12 failures (19%) required further surgery, four (6.3%) for aseptic loosening of the acetabular construct, six (9.5%) for recurrent infection and two (3.2%) for recurrent dislocation requiring captive components. Complications, seen in 11 patients (18.3%), included six femoral or sciatic neuropraxias which all resolved, one grade III heterotopic ossification, one on-table acetabular revision for instability, and three early post-operative dislocations managed by manipulation under anaesthesia, with no further instability.

We recommend support rings and morcellised bone graft for significant acetabular bone deficiency that cannot be reconstructed using mesh.

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.

Total hip replacement with a superolateral bone graft for osteoarthritis secondary to dysplasia

We evaluated the long-term results of 116 total hip replacements with a superolateral shelfplasty in 102 patients with osteoarthritis secondary to developmental dysplasia of the hip. After a mean follow-up of 19.5 years (11.5 to 26.0), 14 acetabular components (12%) had been revised. The cumulative survival at 20 years was 78%, with revision for loosening of the acetabular component as the end-point. All grafts were well integrated and showed remodelling. In six grafts some resorption had occurred under the heads of the screws where the graft was not supporting the socket. Apart from these 14 revisions, seven acetabular components had possible radiological signs of loosening at a mean follow-up of 14.5 years, one had signs of probable loosening, and five had signs of definite loosening. These results indicate that this technique of bone grafting for acetabular reconstruction in hip dysplasia is a durable solution for cemented acetabular components.

Acetabular revision surgery with the LOR cup: three to 8 years' follow-up

A retrospective review was conducted to evaluate the mid-term results of the Längsovalen Revisionspfanne oblong revision cup. From July 1995 to March 2000, 41 acetabular revision surgeries were performed for aseptic loosening of the acetabular cup. The acetabular defects were classified as type 2A to 3B, according to Paprosky's criteria. Morselized bone grafts were used in 19 cases (45.2%) to fill cavitary defects. The mean postoperative follow-up was 63.5 months (range, 40-99 months). Clinical assessment at follow-up showed a significantly improved mean Harris Hip Score from 46 points preoperatively to 82.2 points postoperatively, whereas the x-ray examination did not show any sign of loosening of the cups. Data analysis showed that significantly better results were correlated with restoring the hip rotation center and reducing leg length discrepancy.

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.

Acetabular medial wall displacement osteotomy in total hip arthroplasty: a technique to optimize the acetabular reconstruction in acetabular dysplasia

Twenty-six patients (30 hips) who had acetabular dysplasia were operated on by circumferential acetabular medial wall displacement osteotomy to reconstruct the acetabulum during total hip arthroplasty. All patients had cementless acetabular components implanted. The average acetabular component size was 50 mm (range, 44-56 mm). Only 2 hips needed structural bone graft. The mean follow-up period was 22 months (range, 6-32 months). Harris hip score had changed from 47.31 (range, 19-69 points) to 94.69 (range, 85-100 points) postoperatively (P < .01). Using the Ranawat acetabular triangle to determine the optimal hip center of rotation, the postoperative hip biomechanical environment had been improved. Our short-term follow-up suggests this technique is reliable and reproducible and generally avoids the use of bone graft and graft site morbidity. In addition, it allows the use of standard modular cementless components in patients with acetabular dysplasia.

Total hip arthroplasty with a sliding iliac graft for acetabular dysplasia

We describe a new technique of reconstruction of the deficient acetabulum in cementless total hip arthroplasty. The outer iliac table just above the deficient acetabulum is osteotomised and slid downwards. We have termed this an iliac sliding graft. Between October 1997 and November 2001, cementless total hip arthroplasty with an iliac sliding graft was performed on 19 patients (19 hips) with acetabular dysplasia. The mean follow-up was 3.4 years (2 to 6). The mean pre-operative Harris hip score was 45.1 which improved significantly to 85.3 at the time of the final follow-up. No patient had post-operative abductor dysfunction. Incorporation of the graft was seen after two to three months in all patients. Resorption of the graft and radiolucencies were infrequent. This technique is a useful alternative to femoral head autografting when the patient's own femoral head cannot be used.

Revascularization of a total bulk acetabular allograft at 14 years

This case report describes the long-term outcome of a total bulk acetabular allograft placed for bone substitution after resection of recurrent pigmented villonodular synovitis of the hip joint. After 14 years in situ, the graft had completely incorporated and showed viable bleeding bone surfaces in all areas of the acetabular implant interface. The possibility of a bulk corticocancellous allograft to undergo revascularization over a long period of time has not been previously documented.

Assessment of bone graft substitutes in autopsy implant retrievals of the acetabulum in total hip arthroplasty

Two autopsy retrievals of acetabular reconstruction with different bone graft substitutes were analyzed. One patient underwent surgery with hydroxyapatite (HA) granules, and the other with demineralized bone chips. Incorporation occurred with the biomaterial bone-graft substitute HA primarily in the superior part of the acetabulum, where the HA was in contact with host cortical bone. No bony union occurred with the demineralized bone chips because of motion and migration of the acetabular cup. No bone incorporation of either bone-graft substitute was observed in the medial wall defects in both patients. There were two important findings: (1) the 3- to 8-mm depth and 70% to 75% surface of union of the HA bone graft substitute to host cortical bone was the same as seen with morselized, fresh-frozen bone graft; and (2) union of graft material to host bone was dependent on secure fixation of the acetabular construct.

Technical factors for success with metal ring acetabular reconstruction

Sixty-four hips in 62 patients were revised with a Mueller ring (28 hips), Ganz ring (18 hips), and Burch-Schneider cage (18 hips) under the direction of a single surgeon. A polyethylene cup was cemented into the metal support of all hips. Average follow-up was 4.6 years (range, 2.0-6.7 years). Six rings were revised because of aseptic loosening, and 5 others were radiographically loose, for a mechanical failure rate of 11 of 64 (17%). Acetabular metal ring supports failed by migration when defects of > or =60% of the superior weight-bearing bone were filled by only cement or particulate graft. At the time of surgery, the superior rim of the metal support should be against host-bone for 60% of its support, and if not, the use of bulk allograft, rather than particulate graft, is required. Dislocation was the second failure mechanism identified, and this occurred in 15 hips (23%), with reoperation required in 5 hips (8%). A constrained liner should be used in patients with nonunion of the trochanter and preoperative abductor weakness that grades fair/minus or worse as measured by the side-lying abduction test.

Reconstruction of major column defects and pelvic discontinuity in revision total hip arthroplasty

Acetabular reconstruction with severe bone loss after failed total hip arthroplasty is a difficult problem. Defects were defined as major segmental and cavitary loss (type III anterior or posterior) or pelvic discontinuity (type IV). Seventeen cases were treated, of which 7 were type III and 10 were type IV. Bulk allograft was used in 16 of 17 cases, of which 7 were whole acetabular grafts, 2 were posterior segmental acetabular grafts, and 7 were femoral heads. Fourteen of 17 patients were female. The extensile triradiate approach was used in 12 cases. Long pelvic bone plates were applied to the posterior column and anterior brim of the pelvis in most cases. Allografts united to host-bone in 15 cases. Average follow-up was 83 months. The overall revision rate was 47%, of which 3 of 7 press-fit and 2 of 10 cemented cups had failed. The dislocation rate for the extensile approach was 50%; 2 patients had excisional arthroplasty for infection, and 2 patients had exploration of the sciatic nerve for release from migrating pelvic plate screws. Because of the overall poor results, this approach cannot be recommended for general use.

The management of severe acetabular bone loss using structural allograft and acetabular reinforcement devices

The cases of 37 acetabular reconstructions in 35 patients with major structural pelvic bone loss were reviewed. At an average follow-up of 7.1 years, patients rated their results as excellent in 12 cases (32.4%), good in 22 (59.5%), fair in 2 (5.4%), and poor in 1 (2.7%). Thirty-four cases (91.9%) were classified as a clinical success. Thirty-six allografts (97.3%) had radiographic evidence of full incorporation. Of the unrevised hips, 1 (2.7%) was classified as definitely loose, 2 (5.4%) as probably loose, and 4 (10.8%) as possibly loose. One revision of an acetabular component was required because of late sepsis. This is the first reported series on the use of acetabular reinforcement devices with solid bulk allograft covering more than 50% of the socket. The allograft is protected in the early postoperative period, superior migration of the cup is virtually eliminated as a complication, and the incidence of aseptic loosening is greatly diminished.

Medial protrusio technique for placement of a porous-coated, hemispherical acetabular component without cement in a total hip arthroplasty in patients who have acetabular dysplasia

Twenty-four hip replacements were performed with use of a medial protrusio technique to stabilize the fit of a hemispherical metal shell in the acetabulum in nineteen patients who had dysplasia of the hip. All of the hips were followed for a minimum of five years (average, seven years; range, five to thirteen years). Six of the hips were type I, seven were type II, eight were type III, and three were type IV according to the criteria of Crowe et al. The acetabular cup was implanted with the medial aspect of its dome beyond the Kohler line (drawn from the ischium along the ilioischial line) in all hips. An autogenous graft sculpted from the femoral head was used to cover 15 to 30 percent of the superolateral portion of the cup in one type-I hip, four type-III hips, and one type-IV hip. The need for these six bone grafts could have been avoided by reaming two to three millimeters more medially or by allowing 20 percent of the superolateral portion of the cup to be uncovered. Sixty to 84 percent of each bone graft was resorbed, effectively leaving the superolateral portion of the cup uncovered. The amount of the surface of the cup that was beyond the Kohler line averaged 41 percent for the six type-I hips, 43 percent for the seven type-II hips, 41 percent for six of the type-III hips, and 44 percent for one of the type-IV hips. Crossing of the ilioischial and iliopubic lines was noted on the radiographs of two type-III and two type-IV hips. Radiographs of two type-I hips and one type-II hip showed 7 to 17 percent of the surface of the dome of the cup through the internal pelvic wall (beyond the iliopubic line). None of the twenty-four metal shells were revised. A reoperation was performed on two hips to exchange a worn polyethylene insert, and three femoral components that had been fixed without cement were revised because of mechanical loosening. Wear averaged 0.26 millimeter per year in the fourteen hips that had a titanium femoral head and 0.09 millimeter per year in the nine hips that had a cobalt-chromium femoral head. The remaining hip had a ceramic femoral head, and the wear rate was 0.09 millimeter per year. The medial protrusio technique is a predictable, reproducible method for obtaining fixation of a porous-coated, hemispherical acetabular component in a dysplastic acetabulum. The technique permits the use of a porous-coated (bone-ingrowth) component; avoids the use of support bone graft and thereby reduces the operative time; facilitates rehabilitation by permitting earlier weight-bearing of the hip; and permits the use of a modular bearing surface, which may allow future exchange of only this surface rather than revision of the entire acetabular component because of excessive wear.

Reconstruction of the deficient acetabulum with an oblong prosthesis: three- to seven-year results

A retrospective review was conducted to determine the intermediate-term results of a noncustomized, oblong, porous-coated, cementless, acetabular component designed to obtain stability on host bone while maintaining an anatomic hip center. The clinical and radiographic results were reviewed in 18 patients (3 primary, 15 revision). All patients had substantial acetabular rim defects before reconstruction with the Johnson and Johnson E-15 or E-25 oblong components. The average follow-up was 4.5 years (range, 3.4-6.9 years), with an average postoperative Harris Hip Score of 91 points. Radiographic analysis revealed no prosthetic migration and near anatomic restoration of the hip center.

Role and results of segmental allografts for acetabular segmental bone deficiency

Acetabular reconstruction in both primary and revision hip arthroplasty often requires reconstruction of deficient acetabular bone stock. The exact role of allografts remains controversial. Published results of structural allografting are presented. Recent literature supports the use of segmental allografts for reconstruction of large segmental and combined defects.

Bone grafting in total hip arthroplasty for insufficient acetabulum

We assessed the effectiveness of total hip arthroplasty (THA) supplemented with autologous bone grafts in patients with congenital disease of the hip (CDH). 2 groups of patients were evaluated: In Group A, 33 patients with a mean age of 54 years underwent arthroplasties using a threaded ceramic conical acetabular cup without cement (Autophor). In Group B, 85 patients with a mean age of 55 years underwent arthroplasties using a threaded, noncemented, titanium cup (CST). Bone grafts were supplemented the THA in 3 ways: 1) intrapelvic application using the cotyloplasty technique, 2) as bone chips in order to cover small defects around the upper and lateral part of the cup, and 3) as a bulky corticocancellous graft which was secured with screws. Follow-up averaged 11 and 9 years for patients in Groups A and B, respectively. All the grafts in Group A had consolidated by the end of 6th month. Only 2 partial absorptions were observed, 1 intrapelvic graft and 1 corticocancellous graft. 2 revisions were performed in this group of patients, but neither were related to bone graft absorption. By the end of 6 month, 63 of 85 in Group B had consolidated bone grafts. In 16 patients with intrapelvic cotyloplasty, 3 demonstrated complete and 1 partial absorption of the grafts. 3 cup revisions were performed in this group of patients, all with complete graft absorption. Our findings indicate that autologous bone grafts are strong adjunct for satisfactory fixation of THA in patients with CDH, a particularly demanding group of patients to manage. In addition, the ceramic threaded cup was found to be superior to the titanium threaded cup in terms of both bone graft consolidation and the number of revisions required.

Cementless revision of total hip arthroplasty using the anatomic porous replacement revision prosthesis

This study reports the results of revision total hip arthroplasty with the Anatomic Porous Replacement Revision Hip System (Intermedics Orthopedics, Austin, TX) to investigate the value of cementless fixation. Sixty-six hips in 65 patients were followed for a mean of 4.7 years in patients with a mean age of 56 years. Thirty-six patients were categorized as Charnley class A, 16 as class B, and 13 as class C. Forty (61%) of the femurs were classified before surgery as having loss of bone distal to the intertrochanteric line. Thirty-two (48%) of the femurs required augmentation with demineralized strut cortical allografts, 5 (8%) required bulk femoral allografts, and 12 hips (18%) required acetabular allografts. Overall, 4 stems (6%) and 2 acetabular components (4%) required further revision surgery. The reason for further revision in 1 stem and both acetabular components was allograft failure. Fifty-six (85%) hips had excellent or good Harris hip scores. Ninety percent of hips had no or slight pain, and 90% allowed patients to walk with no or slight limp. Those hips that had hydroxyapatite coating added to the porous coating had statistically improved Harris hip scores for both pain and limp. Stable fixation was present in 95% of stems. Demineralized strut grafts healed in 30 of 32 hips. Thirty-nine of 44 noncemented revision sockets had no radiolucent lines and there were no loose components. Cementless fixation was effective for these hips.

Functional results in total hip replacement in patients 65 years and older

Total hip arthroplasty in patients 65 years and older has been very durable in long term results. Eighty-nine hips in 79 patients were observed for 5 to 9 years to determine the importance of advancing age and deterioration of activity levels to durability of total hip replacement. The age of patients was 65 years or older at the time of surgery. A classification of function was used that graded activity level. During the average 6.24 years of postoperative followup, 22% of the patients died, 38% had medical problems that reduced their functional level, and 10% reduced their function because of their hip surgery. Hip related deterioration occurred only in those patients with a cementless stem. There was decreasing measured wear with increasing age; otherwise, neither age nor activity change in this study was related to loss of fixation of components, osteolysis, or bone remodeling. Increasing age and decreasing activity in patients 65 years and older does not seem to be the primary reason for durability of total hip arthroplasty in these patients. In this age group, the durability of hip replacement is related mostly to the quality of fixation.

Autogenous bone grafts from the femoral head for the treatment of acetabular deficiency in primary total hip arthroplasty with cement. Long-term results

Thirty-five consecutive total hip arthroplasties in twenty-eight patients were performed with use of cement and insertion of an autogenous graft from the femoral head. Five patients (six hips) subsequently died or were lost to follow-up. The results for the remaining twenty-three patients (twenty-nine hips) were reviewed retrospectively at a mean of eleven years (range, seven to seventeen years) after the operation. All of the grafts united. The mean estimated coverage of the acetabular component by the autogenous graft was 27 per cent (range, 15 to 45 per cent). Three sockets (10 per cent) were revised because of symptomatic loosening without infection at a mean of ten years (eight, ten, and twelve years) after the index procedure. All three hips were found to have viable, bleeding bone in the region of the remaining graft. An additional eight acetabular components had a nonprogressive, asymptomatic, continuous radiolucent line at the cement-bone interface. This finding was assumed to indicate loosening of the socket, so the total prevalence of loosening was 38 per cent (eleven of twenty-nine sockets). There was no significant difference between the loose and the well fixed components in terms of the amount of coverage by the graft (p > 0.2) or the method of fixation (p > 0.4). There was no collapse or resorption of the graft that was of mechanical consequence. Autogenous femoral-head bone-grafting is a useful technique with a good potential for long-term success when the amount of coverage by the graft is limited to less than 40 per cent of the surface of the acetabular component.

Failures after revision hip arthroplasties with threaded cups and structural bone allografts. Loosening of 13/18 cases after 1-4 years

Uncemented threaded, smooth cup acetabular components and structural deep-frozen bone allografts harvested from femoral heads during arthroplasties were used for reconstruction of the acetabulum in 18 revision hip arthroplasties. Autogenous bone grafts were also used in every case. The mean follow-up time was 2.5 (1-4) years. Loosening of the prosthetic component occurred in 13 cases. In 8 cases revision of the acetabular component has already been performed, and 5 cases remain to be reoperated. The use of uncemented, threaded cups in combination with reconstruction of bone defects with structural allografts cannot be recommended in acetabular revisions.