Mueller reinforcement rings in acetabular revision: outcome in 164 hips followed for 2-17 years

Reinforcement Ring-Augmented Hip Arthroplasty: A 35-Year Follow-up

During the late 1980s, techniques were evolving to prevent acetabular component loosening. Inadequate acetabular bone stock further complicated this concern, which was traditionally addressed with cementation and bone grafting during this time period. However, one evolving tactic to address acetabular component loosening in the setting of inadequate acetabular bone stock was to augment bone graft with an acetabular reinforcement ring. In 1963, a 26-year-old, active male sustained a right-sided femoral neck fracture following a skiing accident. He ultimately developed a collapsed femoral head and varus deformity of the femoral neck requiring a total hip arthroplasty with a cemented monoblock femoral component and a polyethylene acetabular component cemented into a reinforcement ring. The initial procedure was performed in 1988, and this prosthesis is still functioning 35 years later and represents one of the longest follow-ups of a patient with a primary total hip arthroplasty with a reinforcement ring.

An Observational Prospective Clinical Study for the Evaluation of a Collagen-Hydroxyapatite Composite Scaffold in Hip Revision Surgery

One of the greatest challenges of hip revision surgery is the need to restore extensive bone loss by creating a stable reconstruction with long-term durability. The present observational, investigator-initiated prospective study was carried out to evaluate the clinical and radiological results of the use of a commercial biomimetic collagen-hydroxyapatite composite biomaterial (RegenOss) applied in hip revision surgery. Thirty-three patients who underwent hip revision were included in this study, and 29 received up to 2 years of follow-up. The acetabulum was reconstructed using an uncemented hemispherical shell both with or without an iliac fixation stem. Functional recovery was assessed according to the Harris Hip Score (HHS) at the pre-hospitalisation check-up, and at 6-, 12-, and 24-month follow-ups. Radiological evaluation consisting of X-ray analyses (6, 12, and 24 month follow-ups) and CT scan exams (within 10 weeks post-surgery and at 12-month follow-up) were performed to evaluate the reduction in bone defect and new bone regeneration. All the patients reported a complete recovery and a considerable improvement in functional outcome assessed by the HHS, which was significantly higher at all the follow-ups than at pre-hospitalisation. Moreover, radiological assessments revealed good scaffold integration. Overall, collected data suggest that RegenOss is a valid and safe alternative to restoring acetabular bone loss in revision hip arthroplasty.

Mid-term results in revision hip arthroplasty with impaction bone grafted cup reconstruction for acetabular defects

Acetabular defects are a challenging condition for surgeons in revision THA. A crucial aim is an anatomical restoration of the centre of rotation (COR) through grafts. The aim of this study was to determine the cup survival after biological restoration of acetabular defects in THA and the effect of Paprosky classification, age, BMI, and number of previous operations on cup survival. Retrospectively patients with a cup exchange and an impaction of cortico-cancellous or bulk grafts between 2009 and 2012 were included with a follow up with a minimum of 5 year. Implant failure was defined as radiographic loosening or explantation of the cup. The acetabular defect situation was classified to Paprosky. 82 patients (58 female 70.7%) were included. 26 patients were not available to contact. 56 patients (40 female 71.4%) remained for survival analysis with mean age of 75.6 ± 8 years. Survival of the cup after 5 years was 90% and after 7.8 years 88%. There was no difference in survival concerning defect classification, type of implant or graft, age, BMI, and number of previous operations. Patients on the follow up reached an HHS of 67.4 ± 19, a WOMAC Score of 33.4 ± 25.4 points and an unsatisfactory result in the SF-36. Impaction bone grafting of acetabular defects is a good option with satisfactory biomechanical results and survival for small defects. Predictive factors for cup survival could not be clarified in our study. So, the correct indication, knowing the limits of the methods and the correct choice of implant allow a defect-oriented approach and are decisive for the success of the operation.

Clinical and Radiological Outcome of Acetabular Reconstruction Rings in Complex Primary and Revision Total Hip Arthroplasty

BACKGROUND

Acetabular reconstruction in complex primary and revision total hip arthroplasty (THA) with bone loss poses a great challenge. We aim to evaluate the medium-term clinical and radiological outcome of reconstruction rings used in these difficult situations.

METHODS

We retrospectively reviewed a consecutive series of acetabular reconstructions with Muller ring or Bursh-Schneider cage from January 2009 to December 2016. The reconstruction rings were used in 66 hips (65 patients). There were 41 complex primary THA and 25 revision THA. The mean follow-up period was 76 months (range, 37-167 months). Clinical evaluation includes the assessment of Harris hip score, visual analogue scale (VAS) score, limb length discrepancy, and activities of daily living. The radiographs were analyzed for any signs of loosening, osteolysis, acetabular migration, and heterotopic ossification.

RESULTS

The overall survival rate was 95% for revision in aseptic loosening and 87% for any reason at an average follow-up of 6.3 years. Twelve patients died and 9 patients were lost to follow-up leaving 45 patients for final functional analysis. Among the 45 patients, excellent to good results were seen in 33 patients, fair results were seen in 5 patients, poor results were seen in seven patients. Two patients had aseptic loosening and another two patients developed deep chronic infection awaiting two-stage revision.

CONCLUSION

Reconstruction rings still place a role in the armamentarium for complex acetabular reconstruction. It helps to reliably restore the bone stock, have an acceptable survival rate and satisfactory functional outcome at medium to long-term follow-up.

The Ganz acetabular reinforcement ring shows excellent long-term results when used as a primary implant: a retrospective analysis of two hundred and forty primary total hip arthroplasties with a minimum follow-up of twenty years

PURPOSE

The acetabular reinforcement ring with a hook (ARRH) has been designed for acetabular total hip arthroplasty (THA) revision. Additionally, the ARRH offers several advantages when used as a primary implant especially in cases with altered acetabular morphology. The implant facilitates anatomic positioning by placing the hook around the teardrop and provides a homogenous base for cementing the polyethylene cup. Therefore, the implant has been widely used in primary total hip arthroplasty at our institution. The present study reports the long-term outcome of the ARRH after a minimum follow-up of 20 years.

METHODS

Two hundred and ten patients with 240 primary THAs performed between April 1987 and December 1991 using the ARRH were retrospectively reviewed after a minimum follow-up of 20 years. Twenty-three of 240 hips were lost to follow-up, 110 patients with 124 THAs had deceased without having a revision surgery performed. This left 93 hips for final evaluation. Of those, 75 hips were assessed clinically and radiographically after a mean follow-up of 23.1 years (range 21.1-26.1 years). In 18 cases, clinical and radiographic assessment was omitted because implant revision had been performed prior to the follow-up investigation. The primary endpoint was defined as revision for aseptic loosening.

RESULTS

Out of the 93 hips available for final evaluation, 14 hips were revised for aseptic loosening; another four were revised for other reasons (deep infection n = 2, recurrent dislocation n = 2). The survival probability of the cup was 0.96 (95% confidence interval 0.93-0.99) after 20 years with aseptic loosening as endpoint. Radiographic analysis of the surviving 75 hips showed at least one sign of radiographic loosening in 24 hips. The mean Merle d'Aubigne score increased from 8 points pre-operatively to 15 points at final follow-up (7.5 ± 1.8 vs 15.0 ± 2.3, p < 0.001). The mean HHS was 85 ± 14 at final follow-up. Radiographic loosening did not correlate with the clinical outcome.

CONCLUSIONS

The long-term results of the ARRH in primary THA are comparable to results with standard cemented cups and modern cementless cups. We believe that the ARRH is a versatile implant for primary THA, especially in cases with limited acetabular coverage and altered acetabular bone stock where the ARRH provides sufficient structural support for a cemented cup.

Outcome of cages in revision arthroplasty of the acetabulum: a systematic review

BACKGROUND AND AIM OF THE WORK

To investigate the clinical, radiological and functional outcomes of acetabular revisions with acetabular reinforcement rings and cages.

METHODS

A comprehensive literature study of international databases was performed. Inclusion criteria were cementless revisions, use of reinforcement rings, radiological and clinical follow-up, availability of full text in English, publication between January 1990 and July 2018. In a second further analysis, we selected only studies describing patients with more severe acetabular defects (AAOS 3, AAOS 4, Paprosky III). Data extracted included mean follow-up period, radiographic follow-up, functional scores, implant failures and survival rate.

RESULTS

We included in our review 1327 acetabular revisions described in 28 articles. The most commonly used reinforcement rings were Burch-Schneider ring, the Muller ring and the Ganz ring. Mean follow-up for all patients together was 8.8 years. Clinical or radiological signs of loosening were reported in 191 patients, 83 patients needed further acetabular revision for aseptic loosening and 41 patients received additional surgeries for septic loosening. The mean value of the Harris Hip Score reported at the last follow-up was 76.3. Nineteen articles fulfilled the criteria for further analysis about high-grade acetabular bone defects. We analyzed 649 revisions with mean follow-up period of 8.2 years. Clinical or radiological loosening was reported in 90 patients, additional acetabular revision was performed in 39 patients and 25 patients needed further surgeries for deep infection.

CONCLUSION

Acetabular revisions with cages are characterized by good survival rates and functional scores with a mean follow-up period of 8 years.

Long-Term Results of Acetabular Reconstruction Using Ganz Acetabular Rings

BACKGROUND

Our study examines the long-term results of acetabular reconstruction using the Ganz acetabular reinforcement ring (GRR) in total hip arthroplasty.

METHODS

Between 1998 and 2001, 135 hips (119 revision and 16 primary arthroplasties) were consecutively implanted with a GRR at our hospital. The average age was 65 years (range, 26-90). Clinical and radiographic evaluations were carried out. Long-term survivorship was estimated using a competing risks analysis, and multivariate survivorship using Cox regression model was used to identify risk factors for implant failure.

RESULTS

At a mean follow-up of 16 years (range, 15-18), 3 patients were lost to follow-up and 19 had implant failure: 4 aseptic loosenings without re-revision, 4 septic, and 11 aseptic re-revisions. Survival was estimated at 86% after 16 years (95% confidence interval [CI], 78.5%-90.9%) using radiographic loosening or revision for any reason as the end point. Using aseptic loosening as the end point, the survival was estimated at 91.2% after 16 years (95% CI, 84.5%-95.0%). Multivariate analysis revealed that age at surgery was a significant risk factor for failure of the GRR. With acetabular revision or loosening as the end point, patients ≤60 years had 71.6% (95% CI, 53%-82.8%) and older patients had 92.2% (95% CI, 84%-96.2%) probability of implant survival after a mean 16-year follow-up. The median Harris Hip Scores and Western Ontario and McMaster Universities Osteoarthritis Index scores were 77 and 64.5, respectively, and mean Numerical Pain Rating Scale score was 1.6 at final follow-up.

CONCLUSION

Our long-term study showed acceptable survival and functional results using the GRR in older patients, while young patients had less favorable survival.

Clinical and radiological outcomes of acetabular revision with the Delta Revision TT cup

INTRODUCTION:

This study evaluates mid-term results of acetabular revision using a hemispherical acetabular cup in Trabecular Titanium with a cage construct.

METHODS:

We reviewed 36 acetabular revisions performed with the Delta Revision TT cup in 34 patients (mean age = 75, range: 45-92 years). Acetabular defect types (Paprosky classification) included (1) 2B ( n = 5), (2) 2C ( n = 7), (3) 3A ( n = 15), and (4) 3B ( n = 9). Morcellised bone allografts were used in 24 cases, and synthetic bone used in 11. Outcomes were evaluated using the Harris Hip Score (HHS), and the Verbal Rating Scale (VRS) for pain measurement. X-ray visualisation of cup position was used to discern signs of mobilisation and bone graft incorporation. Survivorship at post-revision follow-up (mean = 39.8; range 12-91.5 months) was calculated.

RESULTS:

HHS increased from 40.5 to 87 ( p < 0.01). 68% of cases were pain free; by comparison, 32% had an average VRS score of 1.9 (range 1-3). The average cup inclination angle was 40.8° (30-52°) postoperatively, compared with 41.2° (30-52°) at follow-up; there were no signs of loosening or mobilisation. Centre of rotation was fully restored in 21 (58.3%) hips. According to Gie classification; bone graft incorporation grades were (1) 3 ( n = 21), (2) 2 ( n = 12) and (3) 1 ( n = 2). The survival rate was 100% for aseptic loosening and 91.7% for any cause of revision.

CONCLUSIONS:

The Delta Revision TT cup promises good clinical and radiographic results at short- to mid-term follow-up, with high rates of survival rate and bone integration.

Revision Total Hip Arthroplasty for Paprosky Type III Acetabular Defect With Structural Allograft and Tantalum Trabecular Metal Acetabular Cup

There are several surgical options for addressing Paprosky type III acetabular defects during revision total hip arthroplasty. In physiologically young and active patients, using structural bone graft to restore bone defects and provide adequate initial support for the revision acetabular component is one such option. This study reports the mid-term results of using a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. A retrospective analysis was performed of the data collected for 20 consecutive hips in 20 patients (mean age, 56.2 years; range, 43-68 years) with minimum 3-year follow-up (mean, 5.4 years; range, 3.3-10.3 years) who had a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. Only 1 hip had cup migration, which was less than 3 mm in vertical and less than 5° in inclination and recognized as loosening without symptoms. All grafts showed good incorporation with trabecular bridging over the graft and host bone. The mean modified Harris hip score showed significant improvement, from 29.7 (range, 11-52) preoperatively to 84.1 (range, 77-91) at the latest follow-up (P<.05). The use of a structural allograft combined with a tantalum trabecular metal acetabular cup in acetabular revision for Paprosky type III defects had a satisfactory mid-term clinical result. This is a viable option for patients with large acetabular shelf defects. [Orthopedics. 2018; 41(6):e861-e867.].

Acetabular reinforcement rings associated with allograft for severe acetabular defects

Acetabular revisions with severe bone defects can be challenging procedures. Several grading systems have been set into place to help the surgeon adequately gauge the degree of bone loss within the acetabulum. Internationally innovative research in orthopedics and bio-engineering has helped with progression of successful techniques and rings to re-establish the normal anatomy of the hip. The purpose of this review is to evaluate the outcomes of the different acetabular reinforcement rings in the setting of severe acetabular defects. A successive report of relevant data from the literature of multiple techniques will be provided. The procedures include the cup-cage, the Müller ring, the Ganz Ring, the Kerboull acetabular reinforcement device (KARD), the graft augmentation prosthesis (GAP) ring, and the Burch-Schneider ring. The main focus of this overview is rings only; other devices such as trabecular augments, custom-made cages, or oblong cups are not discussed. Furthermore, a special emphasis on the surgical technique of the KARD is also given. Procedures using these rings are usually associated with bone grafts either bulk or morselized. When considering the available data on these various rings used for reconstruction of the severely damaged acetabulum, the cup-cage, the KARD, and the Burch-Schneider ring appear to be reliable options for more successful long-term outcomes.

Reconstruction of failed acetabular component in the presence of severe acetabular bone loss: a systematic review

Acetabular revision especially in the presence of severe bone loss is challenging. There is a paucity of literature critiquing contemporary techniques of revision acetabular reconstruction and their outcomes. The purpose of this study was to systematically review the literature and to report clinical outcomes and survival of contemporary acetabular revision arthroplasty techniques (tantalum metal shells, uncemented revision jumbo shells, reinforced cages and rings, oblong shells and custom-made triflange constructs). Full-text papers and those with an abstract in English published from January 2001 to January 2016 were identified through international databases. A total of 50 papers of level IV scientific evidence, comprising 2811 hips in total, fulfilled the inclusion criteria and were included. Overall, patients had improved outcomes irrespective of the technique of reconstruction as documented by postoperative hip scores. Our pooled analysis suggests that oblong cups components had a lower failure rate compared with other different materials considered in this review. Custom-made triflange cups had one of highest failure rates. However, this may reflect the complexity of revisions and severity of bone loss. The most common postoperative complication reported in all groups was dislocation. This review confirms successful acetabular reconstructions using diverse techniques depending on the type of bone loss and highlights key features and outcomes of different techniques. In particular, oblong cups and tantalum shells have successful survivorship.

Excellent long-term results of the Müller acetabular reinforcement ring in primary cup revision

Background and purpose - The original Müller acetabular reinforcement ring (ARR) was developed to be used for acetabular revisions with small cavitary and/or segmental defects or poor acetabular bone quality. Long-term data for this device are scarce. We therefore investigated long-term survival and radiographic outcome for revision total hip arthroplasty using the ARR. Patients and methods - Between October 1984 and December 2005, 259 primary acetabular revisions using an ARR were performed in 245 patients (259 hips). The mean follow-up time was 10 (0-27) years; 8 hips were lost to follow-up. The cumulative incidence for revision was calculated using a competing risk model. Radiographic assessment was performed for 90 hips with minimum 10 years' follow-up. It included evaluation of osteolysis, migration and loosening. Results - 16 ARRs were re-revised: 8 for aseptic loosening, 6 for infection, 1 for suspected infection, and 1 due to malpositioning of the cup. The cumulative re-revision rate for aseptic loosening of the ARR at 20 years was 3.7% (95% CI 1.7-6.8%). Assuming all patients lost to follow-up were revised for aseptic loosening, the re-revision rate at 20 years was 6.9% (95% CI 4.1-11%). The overall re-revision rate of the ARR for any reason at 20 years was 7.0% (95% CI 4.1-11%). 21 (23%) of the 90 radiographically examined ARR had radiographic changes: 12 showed isolated signs of osteolysis but were not loose; 9 were determined loose on follow-up, of which 5 were revised. Interpretation - Our data suggest that the long-term survival and radiographic results of the ARR in primary acetabular revision are excellent.

Revision Total Hip Arthroplasty Using a Cementless Cup Supporter and Iliac Autograft: A Minimum of 15-Year Follow-Up

BACKGROUND

Bone deficiency in revision total hip arthroplasty is a surgical challenge. The Murata-Chiba cup supporter (MC support ring) is an acetabular component supporter for a cementless porous-coated cup. The purpose of this study is to examine the clinical and radiographic outcomes of reconstruction of acetabular bone deficiency using iliac autografts supported by an MC support ring in a revision setting with minimum 15-year follow-up.

METHODS

Fifty-nine consecutive revision total hip arthroplasties (57 patients) using the MC support ring were followed for a minimum of 15 years. Nine hips had American Academy of Orthopaedic Surgeons type II deficiency and 24 had type III defects of the acetabulum. Clinical outcomes were evaluated using the Harris hip score. Radiographic evaluation included assessment for loosening and bone graft incorporation. Kaplan-Meier survival analysis was performed.

RESULTS

At a minimum 15-year follow-up (mean, 17.6 years), 32 patients (33 hips) were alive, 17 patients (18 hips) were deceased, and 8 patients (8 hips) were lost to follow-up. The mean Harris hip score improved from 44.3 to 77.2 at final follow-up. Four hips required reoperation due to deep infection (2 hips) and liner dissociation (2 hips), but no acetabular components were revised for aseptic loosening. Incorporation of the bone graft occurred in all cases. One unrevised patient had radiographic failure. Survivorship at 15 years with re-revision or radiographic failure as the end point was 90.6% (95% confidence interval, 83.0%-98.8%).

CONCLUSION

The reconstruction of acetabular bone deficiency using autografts supported by an MC support ring provided satisfactory clinical and radiological results at 17.6 years postoperatively.

[Treatment of acetabular bone defects in revision hip arthroplasty using the Revisio-System]

BACKGROUND

Many different systems for the management of primary and secondary acetabular defects are available, each with its inherent advantages and disadvantages. The Revisio-System is a press-fit oval mono-block implant that makes a defect-oriented reconstruction and restoration of the center of rotation possible.

MATERIAL AND METHODS

In this study, we retrospectively reviewed the outcome of 92 consecutive patients treated with this oval press-fit cup due to periacetabular bone loss. The average follow-up was 58.2 months. Defects were classified according to D'Antonio. There were 39 type II, 38 Type III, and 15 type IV defects. After an average of 4.9 years, the implant survival rate was 94.6% with cup revision as the end point and 89.1% with revision for any reason as the end point. The Harris Hip Score increased from 41.1 preoperatively to 62.3 postoperatively. The mean level of pain measured with the Visual Analogue Scale (VSA) was reduced from 6.9 preoperatively to 3.8 postoperatively.

RESULTS

The Revisio-System represents a promising toolbox for defect-orientated reconstruction of acetabular bone loss in revision hip arthroplasty. Our results demonstrate that the implantation of the Revisio-System can result in a good mid-term clinical outcome.

Risk factors for failure of revision total hip arthroplasty using a Kerboull-type acetabular reinforcement device

Background

The present study aimed to identify the risk factors associated with revision total hip arthroplasty (THA) failure using a Kerboull-type (KT) plate.

Methods

We analyzed 77 revision THAs using cemented acetabular components with a KT plate for aseptic loosening between May 2000 and March 2012. We examined the association of bone graft type, acetabular bone defects, age at the time of surgery, preoperative Japanese Orthopaedic Association (JOA) score, postoperative JOA hip score, and body mass index, with radiographic failure as the outcome.

Results

The 7.4-year radiographic failure survival rate was 81.6%. The survival rate was significantly different between the beta-tricalcium phosphate (β-TCP) group and the bulk allograft group (p = 0.019). The survival curves were also significantly different between the β-TCP group and bulk allograft group (p = 0.036). American Academy of Orthopaedic Surgeons type IV was significantly associated with radiographic failure (odds ratio [OR]: 15.5, 95% confidence interval [CI]: 1.4–175.4; p = 0.032).

Conclusions

The midterm outcomes of revision THA indicate that type of bone graft and bone defect size may affect radiographic survival rate when using a KT plate.

Reconstruction of AAOS type III and IV acetabular defects with the Ganz reinforcement ring: high failure in pelvic discontinuity

BACKGROUND

Large acetabular defects and pelvic discontinuity represent complex problems in revision total hip arthroplasty. This study aimed to investigate whether reconstruction with the Ganz reinforcement ring would provide durable function in large acetabular defects.

PATIENTS AND METHODS

46 hips (45 patients, 19 male, 26 female, mean age 68 years) with AAOS type III and IV defects undergoing acetabular revision with the Ganz reinforcement ring were evaluated at a mean follow-up of 74 months (24-161 months). Fourteen patients died during follow-up. All surviving patients were available for clinical assessment and radiographic studies. Radiographs were evaluated for bone healing and component loosening. A Cox-regression model was performed to identify factors influencing survival of the Ganz-ring.

RESULTS

In the group of AAOS III defects, 3 of 26 acetabular reconstructions failed, all due to aseptic loosening. In pelvic discontinuity (AAOS IV), 9 of 20 hips failed due to aseptic loosening (n = 4), deep infection (n = 3), and non-union of the pelvic ring (n = 2). With acetabular revision for any reason as an endpoint, the estimated Kaplan-Meier 5-year survival was 86% in type III defects and 57% in type IV defects, respectively. The presence of pelvic discontinuity was identified as the only independent predictive factor for failure of the Ganz ring acetabular reconstruction (AAOS III vs. IV, Hazard ratio: 0.217, 95%, Confidence interval: 0.054-0.880, p = 0.032).

CONCLUSION

The Ganz reinforcement ring remains a favorable implant for combined segmental and cavitary defects. However, defects with pelvic discontinuity demonstrate high failure rates. The indications should therefore be narrowed to acetabular defects not associated with pelvic discontinuity.

Minimum Five-Year Outcomes with Porous Tantalum Acetabular Cup and Augment Construct in Complex Revision Total Hip Arthroplasty

BACKGROUND

The use of a trabecular metal revision shell with metal augmentation to fill segmental or irregular defects during complex revision hip arthroplasty has been shown to provide good short-term results in prior published series. Longer-term results of the several cup-augment constructs used clinically are not known. The objective of this study was to report, with minimum 5-year radiographic and clinical follow-up, the outcome of these various constructs in revision total hip arthroplasty.

METHODS

Eighty-four patients (85 hips) underwent revision total hip arthroplasty with use of porous tantalum augments between 2000 and 2007 at a single institution and were retrospectively reviewed. Fifty-seven of the patients (58 hips) had clinical and radiographic follow-up at a minimum of 5 years. At the time of revision, the majority of the hips had acetabular defects classified as Paprosky Type 3A (28 of 58, 48%) or Type 3B (22 of 58, 38%). Eleven (19%) of the hips also had preoperative pelvic discontinuity. All hips were assessed clinically at a minimum of 5 years with use of the Mayo hip score. Postoperative radiographs were reviewed for implant stability, the presence and location of radiolucent lines and healing of the discontinuity if present.

RESULTS

In 2 (3%) of the 58 hips, the constructs failed because of aseptic loosening of the acetabular component and re-revision was indicated. Six (10%) of the 58 hips demonstrated a radiolucent line between the trabecular metal shell and bone in DeLee and Charnley zone 3. In 1 hip that underwent re-revision and in 5 of the 6 hips with a zone-3 radiolucency, a pelvic discontinuity was present at the time of the index revision. The mean preoperative Mayo hip score was 35.7, which improved to 61.9 at 3 months and was 61.7 at the minimum 5-year follow-up.

CONCLUSIONS

With failure defined as aseptic loosening requiring repeat revision surgery, this cohort demonstrated 97% survivorship and maintained satisfactory hip function at the minimum 5 years after the index revision surgery. Six of the 11 hips with preoperative pelvic discontinuity either failed or developed a radiolucency in zone 3 and are considered at risk for future revision. Pelvic discontinuity should prompt consideration of the addition of adjunctive fixation or the use of alternative techniques.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Excellent long-term results of the Müller acetabular reinforcement ring in primary total hip arthroplasty: A prospective study on radiology and survival of 321 hips with a mean follow-up of 11 years

BACKGROUND AND PURPOSE

The original Müller acetabular reinforcement ring (ARR) shows favorable medium-term results for acetabular reconstruction in total hip arthroplasty, where it is used when the acetabular bone stock is deficient. However, there are no data regarding long-term survival of the device. We therefore investigated long-term survival and analyzed radiological modes of failure.

PATIENTS AND METHODS

Between 1984 and 2002, 321 consecutive primary arthroplasties using an ARR were performed in 291 patients. The mean follow-up time was 11 (0-25) years, and 24 hips were lost to follow-up. For survival analysis, we investigated 321 hips and the end of the follow-up was the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 160 hips with a minimum of 10 years of follow-up and with radiographs of sufficient quality. It included evaluation of osteolysis, migration, and loosening.

RESULTS

12 ARR THAs were revised: 1 isolated ARR revision for aseptic loosening, 4 revisions of the ARR and the stem for aseptic loosening, 6 for infection, and 1 for recurrent dislocation. The cumulative revision rate for all components, for any reason, at 20 years was 15% (95% CI: 10-22), while for the ARR only it was 7% (95% CI: 4-12) for any reason and 3.4% (95% CI: 1-9) for aseptic loosening. 21 (13%) of 160 ARR THAs examined had radiological changes: 7 had osteolysis but were not loose, and 14 were radiologically loose but were not painful and not revised.

INTERPRETATION

Our data suggest that the long-term survival of the ARR is excellent.

Acetabular reconstruction with a reinforcement device and bone grafting in revision arthroplasty-a mean five years of follow-up

PURPOSE

To evaluate the clinical and radiological outcomes of acetabular reconstruction using a reinforcement device (RD) in combination with bone grafting in Paprosky type 2 and 3 acetabular bone defects.

METHODS

Morselised bone grafts were used to fill cavitary defects and a structural graft placed in the superior part of the acetabulum in cases of cranial bone defects, with a proximally fixed RD (Protetim, Hódmezővásárhely, Hungary) implanted in all cases. Construct stability, device positioning, hip centre of rotation and medial acetabular wall thickness were evaluated radiologically. Survival rates were estimated with aseptic loosening and revision for any reason as endpoints.

RESULTS

The 28 patients (29 hips) were followed for 4.8 ± 2.7 years (range, 2-10.4 years). Hip centre of rotation was lowered in all cases, with no significant differences between the mean values obtained post-operatively and at the last follow-up. Medial acetabular wall thickness and RD abduction angle were maintained up to the last evaluation. Bone grafts integrated by two years post-operatively in the majority of cases. Kaplan-Meier survival rates were 85.2 % and 82.1 % for the two endpoints at ten years.

CONCLUSIONS

Acetabular reconstruction using a proximally fixed RD in combination with bone grafting offered good mid-term results in the treatment of acetabular bone defects. In cases of severe bone loss, the structural allograft allowed placement of the RD with ischial contact, rendering survival rates similar to RDs with both iliac and ilioischial fixation. The technique was successful in restoring and maintaining medial acetabular bone stock and construct stability for up to ten years.

Long-Term Outcome of Acetabular Reconstruction Using a Kerboull-Type Acetabular Reinforcement Device with Hydroxyapetite Granule and Structural Autograft for AAOS type II and III Acetabular Defects

We evaluated the clinical results of the reconstruction of acetabular bone deficiency using hydroxyapatite (HA) granules and structural autografts supported by a Kerboull-type acetabular reinforcement device at a minimum of 10 years follow-up. Between 1993 and 2003, 40 consecutive THA revisions were performed in 37 patients with a mean age of 66.4 years. The mean follow-up period was 12.8 years. Radiologically, 5 hips failed, of which 2 were revised. The survival rate of the acetabular component at 10 years was 100% in type II defects and 94.9% in the type III defects, using acetabular revision for loosening as the end point. Acetabular reconstruction with HA granules, structural autografts and a Kerboull-type acetabular reinforcement device provided satisfactory clinical and radiological results at 12.8 years postoperatively.

Similar outcomes between two-stage revisions for infection and aseptic hip revisions

PURPOSE

Two-stage revision hip arthroplasty using an antibiotic-loaded spacer is the most widely performed procedure for infected hip arthroplasties. The clinical outcome of this type of surgery compared with aseptic joint revision with exchange of femoral and acetabular components is still controversial due to the relative lack of medium- to long-term follow-up. Therefore, we analysed clinical and radiological outcomes of septic two-stage revisions compared with aseptic hip revision surgeries.

METHODS

In this retrospective study we assessed 82 consecutive patients who underwent two-stage revision for septic total hip (45 patients) or one-stage aseptic revision arthroplasty (37 patients). The average follow-up was 53 months for the aseptic group and 55 months for the septic group. For clinical evaluation, we used the Harris Hip Score (HHS) and the Merle d'Aubigné and Postel score. The postoperative pain level was determined with the visual analogue pain scale.

RESULTS

The surgeries were performed 124 months (aseptic group) and 119 months (septic group) after primary total hip arthroplasty on average. The main indications for aseptic revision surgeries were aseptic loosening (96%), dislocation (2.2%), and periprosthetic fracture (2.2%). In the clinical outcome patients achieved 75.5 points in the aseptic group and 73.4 points in the septic group in the Harris Hip Score. The Merle d'Aubigné and Postel Score revealed 12.5 points for the aseptic group and 13.1 points for the septic group. Mean level of persisting pain was 0.8 (aseptic group) and 0.4 (septic group) on the visual analogue scale (VAS). Overall survival in the aseptic group was 85.6% at 9.8 years 82.7% at 10.1 years for the septic group, with a repeat revision rate of 8.1% and 6.7%, respectively.

CONCLUSIONS

Performing aseptic acetabular and femoral revision hip arthroplasty showed equal clinical outcomes in relation to septic two-stage revision hip surgeries. Our results showed a tendency for better outcome in comparison with the information given in the literature for septic and nonseptic exchange arthroplasties, including a lower rate of re-revisions.

Early results of revision acetabular cup using antiprotrusio reconstruction rings and allografts

BACKGROUND

Hip arthroplasty is one of the most frequently performed orthopedic procedures with high scores of success while its most common complication is aseptic loosening of the acetabular component, which may result from host bone loss or even from pelvis discontinuity. The purpose of the study was to evaluate results in patients after revision acetabular arthroplasty with reconstruction rings and allografts.

MATERIALS AND METHODS

Retrospective data was collected from 69 revisions of acetabular components, performed in a group of 69 treated patients (the mean age 65.1 years). Before surgery, the patients had bone defects of type IIb (n = 5), IIc (n = 20), IIIa (n = 27) or IIIb (n = 17), according to Paprosky et al.

RESULTS

The mean followup period of the patients was 7.2 years (range 3-19 years). A Kaplan-Meier analysis showed that a 3- and 10 year survival rate was 92.8% and 84.8% respectively, using further revision for any reason of the acetabular device as an end point. Eight patients revealed implant related complications. Four patients presented with ring loosening, one with a loose acetabular polyethylene cup, two hips demonstrated recurrent dislocations and one patient was with deep infection. Regarding the remaining 61 patients without re-revision surgery, the mean Harris hip score improved from 30.5 to 73.8 points.

CONCLUSION

A modified, antiprotrusion cage provides an acceptable survival rate and radiological results, but complications could still be expected. It seems that the observed massive bone loss with pelvic discontinuity and an insufficient fixation of the cage to the ischium may result in implant loosening. Stable fixation of the ischial ring flange with screws is an essential condition to expect a good outcome.

Options for managing severe acetabular bone loss in revision hip arthroplasty. A systematic review

Revision hip arthroplasty in the presence of severe acetabular bone loss is challenging and requires a solid understanding of current techniques. A literature search of multiple databases applying specific criteria revealed a total of 50 articles of level IV scientific evidence comprising 2415 patients (2480 hips) managed with reinforcement devices (roof-reinforcement rings and anti-protrusio cages), custom-made triflanged acetabular components (CTACs), jumbo cups and tantalum metal (TM) systems. Overall, patients had improved postoperative hip scores for each technique. The use of reinforcement devices resulted in a mean revision rate of 8.2% and a mean complication rate of 29.21%. CTACs were associated with a revision rate of 15.9% and had a complication rate of 24.5%. Jumbo cups were revised in 8.8% of patients and had a complication rate of 18.4%. TM systems had an overall revision rate of 8.5% with complications seen in 18.5% of patients. CTACs had considerably higher revision rates compared to the other techniques. Jumbo cups and TM systems had lower complication rates compared to the use of reinforcement devices and CTACs. The most frequently occurring complications seen throughout the series were aseptic loosening, dislocation and infection.

Acetabular defect reconstruction in revision hip arthroplasty with a modular revision system and biological defect augmentation

PURPOSE

Revision of failed total hip arthroplasty with severe acetabular bone loss represents a rare but challenging problem. Anatomic reconstruction with biological defect augmentation as solid bone transplants or cancellous bone restores bone stock while providing good component stability. The objective of this study was to present short- to mid-term results of revision total hip arthroplasty with a modular ring system in a consecutive series of patients with severe acetabular bone loss.

METHODS

We retrospectively reviewed 39 consecutive patients (39 hips) with severe acetabular bone loss (Paprosky type 3 A and 3 B) reconstructed with revision total hip arthroplasty using the cementless modular ring system MRS-Titan®. The MRS-Titan® consists of independent ring systems that are adapted modularly to the defect situation. Combined with acetabular defect reconstruction by using cancellous bone in impaction grafting technique, the MRS-Titan® system offers a cement-free revision system that enables defect-adapted customization to individual anatomic matters, bridging of the acetabular bone defect and reconstruction of the centre of rotation. Initial stability of the implant was obtained by screw fixation. Harris hip score and sequential radiographs were used to evaluate clinical and radiographic results.

RESULTS

At an average follow up of 31 months (range 12-69 months) 33 of 39 (84.6 %) of the implants were considered radiographically stable without signs of acetabular migration of more than 2 mm in the horizontal or vertical direction, implant rotation or screw breakage. Complications included six implant failures (15 %). We recorded one aseptic loosening of the MRS prosthesis after 20 months. Five patients (12.8 %) had to undergo revision surgery because of periprosthetic joint infection. Two patients had a dislocation postoperatively. The mean Harris hip score improved from 27 ± 14 points preoperatively to 76 ± 15 points at the time of last follow up.

CONCLUSION

By achieving stable implant fixation and providing potential for biological fixation, treatment of severe acetabular bone loss in revision total hip arthroplasty with the modular ring system MRS-Titan provides a durable solution with good clinical and radiographic results and allows us to accomplish major goals of reconstruction.

Revision total hip arthroplasty for large medial defects with witch's hat-shaped structural allografts--minimum 10-year follow-up

A witch's hat-shaped structural allograft can restore bone stock over acetabular medial wall during revision total hip arthroplasty, which may be of importance for future re-revisions. However, long-term results are unclear. A retrospective review of 104 consecutive hips in 96 patients was performed to determine survivorship and functions. The minimum follow-up was 10 years. Nine patients required re-revision for cup aseptic loosening with a mean time to revision of 4.5 years. Kaplan-Meier survivorship was 89.4% at the endpoint. Radiographic evaluation revealed sixteen instances of minor medial wall graft absorption without significant cup migration. The mean modified Harris Hip Scores were 36 preoperatively and 86 at last follow-up. Revision acetabular surgery using a witch's hat-shaped allograft to restore acetabular medial wall provides an excellent alternative.

Loosening after acetabular revision: comparison of trabecular metal and reinforcement rings. A systematic review

The best method of revision acetabular arthroplasty remains unclear. Consequently, we reviewed the literature on the treatment of revision acetabular arthroplasty using revision rings (1541 cases; mean follow-up (FU) 5.7 years) and Trabecular Metal, or TM, implants (1959 cases; mean FU 3.7 years) to determine if a difference with regard to revision failure could be determined. Failure rates of the respective implants were compared statistically using a logistic regression model with adjustment for discrepancies in FU time. In our study, TM shows statistically significant decreased loosening rates relative to revision rings for all grades including severe acetabular defects and pelvic discontinuity. The severe defects appear to benefit the most from TM.

Multiple Acetabular Revisions in THA - Poor Outcome Despite Maximum Effort

A consecutive series of 52 acetabular revisions was evaluated retrospectively. Inclusion criteria for all patients were at least one former exchange of the acetabular component. Reconstruction was performed with reliable techniques and implants other than extensively porous coated device (e.g. tantalum). The mean follow up was 5.63 (0.01-14.05) years. Cumulative survival at 14.05 years with removal of the acetabular component due to aseptic loosening or the worst case criterion (removal of the acetabular component for any cause and/or lost to follow-up) as the end point was 66.38 (95 % C.-I.: 47.80-84.96) % and 58.42 (95 % C.-I.: 41.01-75.83) %, respectively. The cumulative survival rate with mechanical failure of the acetabular reconstruction as the endpoint was significantly lower in patients with two or more previous revisions in comparison to those with only one former procedure (log rank test: p=0,0112 respectively). The mean Merle d'Aubignée-score improved from 7.3 (0-14) preoperatively to 10.6 (0-17) points at latest follow up examination.Survival of acetabular reconstructions with common techniques and implants is decreasing with the number of previous revisions. This may cause major concerns with regard to the rising number of patients needing repeated revisions. Maximizing durability of primary THA, precise preoperative planning as well as improved techniques and implants for revision may decrease this problem in the long term.

Load dispersion effects of acetabular reinforcement devices used in revision total hip arthroplasty: a simulation study using finite element analysis

Several types of acetabular reinforcement devices are used to prevent the collapse of grafted bone in revision total hip arthroplasty. However, it remains unclear how the stress is reduced by different devices. We used finite element analysis to evaluate 4 types of acetabular reinforcement devices: Kerboull-type device, Burch-Schneider anti-protrusio cage, Mueller ring, and Ganz ring. The control was a socket fixed with bone cement without any reinforcement devices. The stress distribution on the inner surface of each socket was calculated by binarization image processing. For all 4 reinforcement devices, the stress was reduced to less than one-half of that in the control. All the devices were useful for preventing the collapse of bulk bone grafts applied to load-bearing defects.

Functional and Emotional Results Differ After Aseptic vs Septic Revision Hip Arthroplasty

BACKGROUND

It is widely believed that a deep implant infection leads to poor functional and emotional outcomes following total hip arthroplasty.

QUESTIONS/PURPOSE

The purpose of this retrospective comparative review was to determine if patients who undergo two-stage, septic revision hip arthroplasty will have decreased emotional and general health scores, in addition to decreased function, compared to the aseptic revision group.

PATIENTS AND METHODS

One hundred forty-five of 195 patients who underwent aseptic total hip revision for aseptic loosening (mean follow-up = 61 months) and 45 of 73 patients who underwent two-stage, septic revision hip arthroplasty (mean follow-up = 48 months) met the inclusion criteria and had a technically successful outcome. All patients were retrospectively evaluated using Harris Hip Scores (HHS), ad hoc questions, and the SF-36 Health Survey.

RESULTS

The average HHS were 73.2 ± 20.5 (aseptic) and 57.4 ± 20.6 (septic). Significant differences in the SF-36 Health Survey were found between the two groups in: physical functioning (p = 0.026) and role limitations due to physical health (p = 0.004). No significant difference in SF-36 scores was seen in: Energy/Fatigue, General Health Perception, Personal or Emotional Problems, Role Limitations due to Emotional Well Being, Social Functioning, and Bodily Pain.

CONCLUSIONS

Two-stage, septic revision produces a poor functional outcome compared to aseptic revision; however, the overall impact of a septic revision emotionally and socially was not significantly different than patients undergoing aseptic revision.

Structural allograft as an option for treating infected hip arthroplasty with massive bone loss

BACKGROUND

Revision of the infected hip arthroplasty with major bone loss is difficult. Attempts to restore bone stock with structural allograft are controversial.

QUESTIONS/PURPOSES

We assessed the (1) reinfection rate; (2) rerevision rate; (3) radiographic graft union, resorption, and implant migration; (4) Harris hip scores at 1 year and at last followup compared with before surgery; and (5) other major complications associated with the use of bulk structural allograft to treat massive bone loss in infected hip arthroplasty.

METHODS

We retrospectively reviewed 27 patients who underwent two-stage revision arthroplasty using structural allograft to treat massive bone defects in infected hip arthroplasty. There were 17 proximal femoral grafts, three acetabular major column grafts, two acetabular minor column grafts, and 10 cortical strut grafts used. Five patients had combinations of two allografts. The minimum followup was 1.1 years (mean, 8.2 years; range, 1.1-16.8 years).

RESULTS

One of 27 patients had reinfection. The Kaplan-Meier survivorship was 93% at 10 years with rerevision for aseptic loosening as the end point. Radiographically, three patients had nonunion at the graft-host junction. All patients except two had graft resorption, of which all were mild except two, which were severe. Three patients had implant migration. The mean modified Harris hip scores were 39.2 points (range, 25-60) preoperatively, 67.3 points (range, 40-91) at 1-year followup, and 70.3 points (range, 46-81) at last followup. Other major complications included one patient with dislocation and one patient with transient sciatic nerve injury.

CONCLUSIONS

Based on our data, we believe the use of structural allografts is a reasonable option for treating massive bone loss in infected hip arthroplasties.

LEVEL OF EVIDENCE

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

[Standardized reconstruction of acetabular bone defects using the cranial socket system]

OBJECTIVE

Management of primary or secondary acetabular bone loss (D'Antonio type I-IV ). Implantation and stable fixation using a cementless, cranially extended oval press-fit cup to restore painless joint function and loading capacity.

INDICATIONS

Septic or aseptic loosening of the acetabular component after total hip arthroplasty. Acetabular bone loss after tumor resection. Primary acetabular bone defects in developmental dysplasia of the hip.

CONTRAINDICATIONS

Persistent deep infection. Bone defects including the parts of the iliac bone adjoining the sacrum (fixation of the stem in the ilium is not possible any more).

SURGICAL TECHNIQUE

Complete exposure of the acetabular defect using a standard approach. Removal of the loose cup. Excision of soft and granulation tissue from the acetabular ground and the rim. Reaming of the acetabulum with sequentially larger hemispheric reamers until an adequate bony bed is created for the insertion of the cranial socket. Eccentric cranial sockets without a craniolateral flap are preferable for use in type I and II defects with teardrop lysis mostly involving the craniolateral acetabulum, if a trihedral press-fit fixation can be achieved. Supplementary screw fixation through the acetabular ground, is possible. If a type III defect is present, the authors recommend the use of cranial sockets with an anatomic flap in order to increase primary stability by supplementary screw fixation. This is especially recommended for the management of deficiencies in the medial or posterior wall. If there is pelvic discontinuity (type IV), adequate acetabular reconstruction with primary stability of the component can only be achieved by a supplementary intramedullary structured stem fixed in the dorsal part of the ilium.

POSTOPERATIVE MANAGEMENT

Partial loading of the operated limb with 10 kg for a period of 6-12 weeks. Then increased loading with 10 kg per week. Thrombosis prophylaxis until full weight bearing. Physiotherapy and gait training.

RESULTS

A total of 50 cup revisions using the ESKA cranial socket system were clinically and radiologically analyzed with an average follow-up of 65.7+/-28.5 months (26-123 months). Defects were classified according to D'Antonio. There were 21 type II, 23 type III, and six type IV defects. The Harris Hip Score increased from 40 preoperatively to 68.3 points postoperatively. Four patients had recurrent hip dislocation requiring replacement of the inlay. In four cases of aseptic loosening, the acetabular component had to be revised. With revision of the acetabular component as an endpoint, implant survival was 92% after an average of 5.4 years.

Long-term results for minor column allografts in revision hip arthroplasty

BACKGROUND

While acetabular structural allografts provide an important alternative for reconstructions, concerns remain with long-term graft resorption, collapse, and failure. Midterm studies of minor column (shelf) allograft suggest reasonable survival but long-term survival is unknown.

QUESTIONS/PURPOSES

We therefore assessed long-term graft/cup survivorship, functional scores, radiographic resorption, and complications associated with minor column allograft.

METHODS

We retrospectively reviewed 74 patients (85 hips) with a mean age of 54 years (range, 28-83 years) undergoing acetabular cup revision using a minor column allograft. A minor column allograft was used in uncontained acetabular bone defects sized between 30% and 50% of the acetabulum. Graft failure was considered to occur when the graft required revision with another graft, metal augment, reconstruction cage, or excision arthroplasty. The minimum followup was 5 years (mean, 16 years; range, 5.3-25 years).

RESULTS

Twenty-three patients (27 hips) had rerevision for all causes at a mean time to rerevision of 6.9 years (range, 0.1-23). Fifteen grafts failed at a mean time-to-rerevision of 6.1 years (range, 0.5-23.2). The 15- and 20-year Kaplan-Meier survivorships were 61% and 55% for cups and 78% for grafts with rerevision for all causes as end point. With rerevision for aseptic loosening as end point, survivorships were 67% and 61% for cups and 81% for grafts. The mean modified Harris hip scores were 41 (range, 20-60) preoperatively, 73 (range, 40-95) at 1 year postoperatively and 73 (range, 26-93) at last followup.

CONCLUSION

The data may provide a long-term benchmark by which future treatments for Type III defects can be measured.

Radiological evaluation of allograft reconstruction in acetabulum with Ganz reinforcement ring in revision total hip replacement

BACKGROUND

In revision total hip replacement (THR), cages and rings are commonly used for the reconstruction of bone defects that are due to mechanical loosening of the acetabular cup and migration of the femoral head prosthesis. The purpose of this study was to evaluate the radiological results of the use of Ganz reinforcement rings with bone allografts in acetabular revision THR.

METHODS

We reviewed 30 hips of 28 patients who underwent allograft reconstruction of the acetabulum with a Ganz reinforcement ring in revision THR. The average postoperative follow-up period was 8 years. The position of the acetabular socket was measured on anteroposterior radiographs. Loosening of the acetabular component was defined as a change in the cranial or central direction of the cup or a change in the cup inclination angle at the time of last follow-up. In cases of segmental bone defects in weight-bearing areas, we used two or three strut screws prior to incorporation of the Ganz reinforcement ring to act as struts for the ring. Kaplan-Meier survivorship analysis was performed. The end point was revision surgery done because of defined loosening of the acetabular component at the time of the last follow-up.

RESULTS

All five acetabular components (16.7%) defined as showing aseptic loosening were type D defects (cranio-central defects), but no patient needed revision surgery during the follow-up period. Nine revision surgeries with strut screws for type D acetabular bone defects were performed. The calculated Kaplan-Meier survival rate at 5 years was 96.0%, and the rate at 10 years was 80.2%, using defined loosening of the acetabular component as the end point.

CONCLUSIONS

Allograft reconstruction of the acetabulum with a Ganz reinforcement ring is a useful technique for revision THR. Occasionally, a special technique (the strut screw technique) was required for the reconstruction of type D bone defects.

[Hip implant revision. Avoiding mistakes and managing risk]

Hip revision surgery may lead to unexpected complications, with a negative impact on the treatment outcome. To refer to possible difficulties as"mistakes" is less helpful than defining ways to foresee such difficulties and developing possible strategies to avoid them. This approach requires a comprehensive amount of personal experience, which may follow consideration of some basic"rules" and possible surgical scenarios before an intervention. The author presents an individual risk management approach that includes hints on how to foresee the occurrence of certain intraoperative difficulties and how to help avoid errors by incorporating forward-thinking strategies into hip revision surgery.

Cemented hip revision surgery in severe acetabular defects using a semirigid acetabular reinforcement ring--a 5- to 25-year follow-up study

Between 1978 and 1998, a total of 38 consecutive acetabular component revisions were performed in 38 patients. Average age was 67 years, and 87% of patients had severe uncontained segmental acetabular defects of more than 50%. We describe the operative technique of acetabular component revisions performed with bone grafting and a steel, semirigid acetabular reinforcement ring (Eichler), and long-term results are presented. After an average of 11.2 years follow-up, 1 cup was revised after 0.8 years for mechanical loosening, but the ring remained stably fixed. Remodeling (partial) of autografts occurred in all cases. The average HHS was 72.5. The Eichler reinforcement ring is a viable option for segmental acetabular defects in revision hip surgery, allows for restoration of pelvic bone, and makes future revisions feasible.

[Acetabular reinforcement rings in revision total hip arthroplasty: midterm results in 298 cases]

BACKGROUND

Acetabular revision in total hip arthroplasty (THA), especially for loose or migrated cup components with collateral bone loss, remains a great surgical challenge. The aim should always be a functionally favorable reconstruction of the rotation center with sufficient load capacity of the acetabulum. Commonly used implants in Europe are the Mueller ring, the Ganz ring, and the Burch-Schneider cage.

PATIENTS AND METHODS

We report our results of 298 patients (298 hips) with a median follow-up period of 4 (range 0-17) years in a retrospective series.

RESULTS

Follow-up data were available in 224 cases (75%). A radiographic examination was performed in 176 (59%) patients. Another 54 patients (18%) had died in the follow-up period, while another three patients (1%) were lost to follow-up. Eighteen patients (16%) underwent re-revision, in nine cases for aseptic loosening and in the remaining nine cases for infection. In seven additional cases (2%), radiological and clinical failure was found during follow-up. The overall survival rate was 94% at 5 years and 89% at 8 years.

CONCLUSION

Revision THA using acetabular reinforcement rings results in acceptable midterm results. However, septic complications and lysis of the bone graft with consecutive failure of the reinforcement ring remain problematic.

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.

Total hip arthroplasty in acetabular deficiency: experience in Al Razi Hospital, Kuwait

OBJECTIVE

To report clinical and radiological outcomes of cemented and cementless total hip arthroplasty for primary and secondary osteoarthritis with a deficiency of acetabular bone stock.

SUBJECT AND METHODS

Thirty-seven patients (16 male and 21 female) having 41 hips affected by primary and secondary acetabular bone stock defect that were operated using cemented (n = 25) and cementless (n = 16) hip replacement were followed for an average period of 37 (range 12-100) months. Bone defect was classified according to American Academy of Orthopedic Surgery criteria. Different types of bone graft techniques and metal reinforcements were used. Merle d'Aubigné clinical score was used to calculate clinical outcomes. Geometrical position of the acetabular component, cup integration, hip center and graft integration were assessed.

RESULTS

The mean clinical score improved significantly from 10.6 patients preoperatively to 16.7 patients postoperatively; 95% of the cups were in the desired position and were considered integrated and the bone graft remodeled in most cases. There were 2 deep infections, 1 dislocation and 2 cases of transient neurological deficit. No significant differences in final clinical and radiological outcomes, rate of loosening and rate of complications were found between cemented and cementless acetabular replacements.

CONCLUSION

The results show that reconstruction of acetabular bone deficiency can be accomplished with few complications using either a cemented or cementless acetabular component with or without grafting according to the clinical situation.