Reconstruction of the rotation center of the hip after oblong cups in revision total hip arthroplasty

Background

The preoperative bone defect and the reconstruction of the center of rotation of the hip are critical in acetabular revision surgery. Uncemented oblong cups are employed in order to manage these issues. We analyzed the clinical results and rates of revision of two different uncemented oblong cups, the reconstruction of the center of rotation of the hip, as well as the rate of radiological loosening and possible risk factors.

Materials and methods

Forty-five patients (46 hips) underwent acetabular revision surgery using two different uncemented oblong cups. We assessed the clinical results and the survival rate for revision and aseptic loosening. Intraoperative bone loss was classified according to Paprosky, and acetabular reconstruction was assessed according to Ranawat. The mean follow-up was 7.2 years (range 4–11 years).

Results

There were four re-revisions (three due to aseptic loosening); the survival rate for re-revision due to aseptic loosening was 60.1 % at seven years. The mean distance between the center of the femoral head prosthesis and the approximate center of the femoral head improved from 21.5 to 10.2 mm. Thirteen cups showed radiological loosening; the survival rate for radiological loosening at seven years was 40.54 %. A smaller postoperative horizontal distance was correlated with cup loosening.

Conclusions

Although optimal acetabular reconstruction can be achieved by using oblong uncemented cups in revision hip surgery, the clinical and radiological results are not encouraging. Excessive medialization of the cup may increase the rate of loosening.     

Modular acetabular reconstructive cup in acetabular revision total hip arthroplasty at a minimum ten year follow-up

Purpose

Modular acetabular reconstructive cups have been introduced in an attempt to offer initial rigid fixation by iliac lag screws and ischial pegs, to support bone grafts with a flanged metal socket, and to restore original hip center in acetabular revision. The purpose of this study was to clarify minimum ten year follow-up results of this cup system with morsellised allografts in revision cases.

Methods

We retrospectively investigated 54 acetabular revisions at a mean of 11 years (range, ten to 14 years). The indications were Paprosky’s type 2B (eight hip), 2C (eight hips), 3A (23 hips), 3B (nine hips), and 4 (six hips).

Results

Using aseptic loosening as the endpoints, the survival rate was 89.3 % (95 % CI 81–98). Radiographically, one type 3A hip, three type 3B hips and one type 4 hip showed aseptic loosening while no type 2 hips or no cemented cups showed loosening.

Conclusions

The modular reconstructive cups for acetabular revision showed bone stock restoration and stable implantation.     

Impaction bone grafting and a cemented cup after acetabular fracture

Purpose

Patients suffering from post traumatic osteoarthritis of the acetabulum often require a total hip arthroplasty at a relatively young age. Long-term data outcome studies for this population are lacking. We report on the long-term outcome of 20 acetabular fractures in 20 patients treated with impaction bone grafting and a cemented cup after a mean follow-up of 18 years (range, 12–26 years).

Methods

The group consisted of 14 males (70 %) and six females (30 %) with an average age of 53.3 years (range, 35–75 years) at time of surgery. No patients were lost to follow-up. Four patients died and three patients underwent a revision; at review 13 patients were still living with their implant in situ. Survivorship analysis was performed at 20 years follow-up for three endpoints.

Results

Survival rate with endpoint revision for any reason at 20 years postoperative was 74.7 % (95 % confidence interval (CI), 40–91 %), 80.0 % (95 % CI, 41–95 %) for endpoint aseptic loosening, and 63.9 % (95 % CI 32–84 %) for endpoint radiographic failure. Three acetabular components were revised at 14.5, 15.3, and 16.7 years postoperative. Two cups failed for aseptic loosening and one cup failed due to septic loosening. The average postoperative Harris hip score was 82 (range, 56–100).

Conclusion

Acetabular reconstruction with impaction bone grafting and the use of a cemented cup after acetabular fracture is an attractive technique with acceptable long-term results and a low complication and re-operation rate.     

A cementless hip system with a new surface for osseous integration

Purpose

The failure of total hip systems caused by wear-particle-induced loosening has focused interest on factors potentially affecting wear rate. Remnants of the blasting material were reported on grit-blasted surfaces for cementless fixation. These particles are believed to cause third-body wear and implant loosening. The purpose of this study was to evaluate the early clinical and radiological outcomes of a cementless hip system with a new, contamination-free, roughened surface with regard to prosthesis-related failures.

Methods

Between May 2004 and March 2009, 202 consecutive primary total hip arthroplasties (THAs) (192 patients with a mean age of 62.6 years) were performed using a cementless stem (Hipstar®) and a hemispherical acetabular cup (Trident®).

Results

At a minimum follow-up of two years, five revisions (2.5 %) due to aseptic loosening of the stem and three (1.5 %) of the cup were necessary. The cumulative rate of prostheses survival, counting revision of both components and with aseptic failure as end point, was 92.9 % at 8.8 years. Radiolucent lines up to three millimetres were evaluated in the proximal part of the femur in 61 % of cases.

Conclusions

Although the incidence of radiolucent lines was decreased, the revision rate was considerably increased compared to other uncemented hip implants with grit-blasted surfaces in the short- to mid-term follow-up of our study. Subsequent studies are needed to confirm whether these changes in implant material and surface affect the radiological and clinical outcome in the long term.     

Acetabular cup positioning in revision total hip arthroplasty with Paprosky type III acetabular defects: Martell radiographic analysis

Purpose

This study evaluates acetabular cup position in the setting of revision total hip arthroplasty (THA) with severe acetabular bone defects.

Methods

With a definition of safe zone of abduction (30–50°) and anteversion (5–25°), acetabular cup position was measured by a digital image analysis program for 34 patients with Paprosky type III acetabular bone defects.

Results

There were 24 cups (71 %) for abduction and 26 cups (76 %) for anteversion located in the safe zone. Nineteen cups (56 %) were within the safe zone for both abduction and anteversion. There was no dislocation, however one cup out of the safe zone resulted in early cup failure due to aseptic loosening.

Conclusions

The acetabular cup positioning in patients with Paprosky type III defects was 'optimal' in half of the cases. The prevalence of optimal acetabular cup position was similar to those reported in primary THA, suggesting that the presence of a large acetabular bone defect may not be a significant risk factor for suboptimal acetabular cup positioning in the setting of revision THA.     

Survivorship analysis of cemented total hip arthroplasty acetabular components implanted with second-generation techniques

The clinical and radiographic results of primary cemented total hip arthroplasty performed by a single surgeon, with particular emphasis on the performance of acetabular components implanted with so-called second-generation cement techniques, were studied. Seventy hips with 48 metal-backed and 22 polyethylene acetabular components were followed for a mean of 9 years (range, 5–11.5 years). The clinical results were evaluated using a recognized hip score. The fixation status of the cemented acetabular component was evaluated using two methods of measuring radiolucent lines at 5 years and at the last evaluation. Acetabular component loosening was defined as a circumferential radiolucent line, component migration, or revision for loosening. This study was unable to confirm the findings of others that demonstrated higher failure rates with cemented metal-backed components when compared with all-polyethylene components. The survival of cemented acetabular components with 28-mm head femoral prostheses was worse than the survival of cemented acetabular components with 22-mm femoral heads in other published reports, despite advances in cement techniques. Because of the high rate of loosening of cemented 28-mm-inner-diameter acetabular components at 5 and 10 years, the authors no longer use these cemented components for acetabular reconstruction.     

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup. A 15- to 20-year follow-up

This study presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients, at a mean of 16.5 years follow-up (15 to 20). The Kaplan-Meier survivorship for the cup with end-point revisions for any reason, was 79% at 15 years (95% confidence interval (CI); 67 to 91). Excluding two revisions for septic loosening at three and six years, and one revision of a well-fixed cup after 12 years in the course of a femoral revision, the survivorship was 84% at 15 years (95% CI; 73 to 95). At review there were no additional cases of loosening, although seven acetabular reconstructions showed radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.7 cm to 1.0 cm) and a cemented cup, is a reliable technique of reconstruction, when assessed at more than 15 years.     

Results at a minimum of 10 years of follow-up for AMS and PerFix HA-coated cementless total hip arthroplasty: impact of cross-linked polyethylene on implant longevity

Purpose

The purpose of this study was to report results at a minimum of 10 years for hydroxyapatite (HA) coating on the titanium arc-sprayed cementless total hip arthroplasty (THA) and to evaluate the impact of cross-linked polyethylene (XLPE) on implant longevity.

Methods

A total of 131 consecutive primary THAs in 123 patients using an AMS acetabular cup and a PerFix HA stem were retrospectively reviewed. Conventional PE was used for 62 hips (CPE group) and cross-linked PE for 69 hips (XLPE group), with mean follow-up periods of 13 and 11.5 years, respectively. These patients were reviewed using the Japanese Orthopaedic Association (JOA) Hip Score and evaluated in terms of PE wear, osteolysis, and implant survival.

Results

The JOA score improved from 42.6 to 83.9 points at the final follow-up. The mean wear rate of 0.12 mm/year in the CPE group was significantly greater than that of XLPE at 0.007 mm/year. In the CPE group, ten (16.1 %) and two (3.2 %) hips, respectively, underwent PE exchange due to severe wear and acetabular revision due to loosening associated with osteolysis. Three patients had revision in the XLPE group: one cup for aseptic loosening, one PE for recurrent dislocation, and one stem for neck fracture. No evident osteolysis was seen in the XLPE group. Kaplan–Meier survivorship with any revision as the end point shows that the 12-year survival rate was 97.7 % for cups, 93.8 % for PE liners, and 99.2 % for stems. Multivariate analysis revealed that the use of XLPE significantly reduced the risk of revision, with the odds ratio (OR) of 4.3.

Conclusions

AMS and PerFix HA components in this series show excellent implant fixation; however, high rates of PE wear and subsequent osteolysis were limiting factors in long-term success. Low wear rates with XLPE suggest improved implant longevity.     

Low Revision Rates at More Than 10 Years for Dual-Mobility Cups Cemented Into Cages in Complex Revision Total Hip Arthroplasty

BackgroundInstability and aseptic loosening are the two main complications after revision total hip arthroplasty (rTHA). Dual-mobility (DM) cups were shown to counteract implant instability during rTHA. To our knowledge, no study evaluated the 10-year outcomes of rTHA using DM cups, cemented into a metal reinforcement ring, in cases of severe acetabular bone loss. We hypothesized that using a DM cup cemented into a metal ring is a reliable technique for rTHA at 10 years, with few revisions for acetabular loosening and/or instability.MethodsThis is a retrospective study of 77 rTHA cases with severe acetabular bone loss (Paprosky ≥ 2C) treated exclusively with a DM cup (NOVAE STICK; Serf, Décines-Charpieu, France) cemented into a cage (Kerboull cross, Burch-Schneider, or ARM rings). Clinical scores and radiological assessments were performed preoperatively and at the last follow-up. The main endpoints were revision surgery for aseptic loosening or recurring dislocation.ResultsWith a mean follow-up of 10.7 years [2.1-16.2], 3 patients were reoperated because of aseptic acetabular loosening (3.9%) at 9.6 years [7-12]. Seven patients (9.45%) dislocated their hip implant, only 1 suffered from chronic instability (1.3%). Cup survivorship was 96.1% at 10 years. No sign of progressive radiolucent lines were found and bone graft integration was satisfactory for 91% of the patients.ConclusionThe use of a DM cup cemented into a metal ring during rTHA with complex acetabular bone loss was associated with low revision rates for either acetabular loosening or chronic instability at 10 years.     

Results of cemented metal-backed acetabular components: A 10-year-average follow-up study

The clinical and radiographic results of 86 primary total hip arthroplasties performed in 74 patients from 1983 to 1987 with a cemented metal-backed acetabular component and a cemented collared straight femoral stem with a 32-mm head were reviewed at a mean follow-up of 10.1 years. Seven patients (9.2%) underwent acetabular component revision at a mean of 9.0 years after implantation; an additional 24 components (31.6%) demonstrated evidence of radiographic loosening, resulting in a total failure rate of 40.8%. Periacetabular radiolucencies were noted in Charnley zones at the following rates: 34.2% in zone I, 18.4% in zone II, and 27.6% in zone III. In addition, 18.4% and 38.2% of implants demonstrated evidence of migration and excessive polyethylene wear. Excessively vertical cup placement (>49° inclination) at the time of initial arthroplasty was statistically correlated with polyethylene wear, implant migration, and fixation failure. A trend of increasing implant failure was also noted with decreasing polyethylene liner thickness. Periacetabular cement mantle thickness was not statistically correlated with subsequent component loosening or failure. Results of Kaplan-Meier survivorship analysis using revision as an endpoint showed 93.6% survivorship at 10 years and 88.4% at 12 years. The mean modified Harris hip scores were 46.9 preoperatively and 81.8 at final follow-up. The significant overall rates of radiographic loosening, migration, polyethylene wear, and implant revision confirm the suspected trend of increasing failure rates of cemented metal-backed acetabular components over time.     

Biologisch azetabuläre Defektrekonstruktion beim Hüftendoprothesenwechsel mittels „Impaction Grafting“ und azetabulärem Rekonstruktionsring

Objective

Management of acetabular bone defects Paprosky types IIa and IIb in revision hip arthroplasty by rebuilding the bone stock using impaction bone grafting, primary stable reconstruction with an acetabular reconstruction ring, and restoring the hip center of rotation to its anatomical position.

Indications

Acetabular segmental or combined structural defects in the superior acetabular dome with superior/lateral hip center migration with intact anterior and posterior columns (Paprosky types IIa, IIb).

Contraindications

Acute or chronic infections, severe acetabular bone defects preventing adequate anchorage of the prosthesis—particularly destruction of the posterior column.

Surgical technique

Modified transgluteal, lateral approach to the hip joint. Removal of the loose acetabular component. Complete circumferential exposure of the acetabular rim, while maintaining mechanical stability of the remaining bone. Preparation of the homologous spongiosa chips and reconstruction of the acetabular defect in impaction grafting technique. Implantation of the acetabular reconstruction ring and primary stable fixation with cancellous screws in the acetabular dome. Cemented fixation of a polyethylene inlay.

Postoperative management

Mobilization on 2 underarm crutches from postoperative day 1. Partial weight bearing with 20 kg for 6 weeks postoperatively. If plain radiographs show unchanged seating of the prosthesis after 6 weeks, loading can be increased by 10 kg/week until full weight bearing is achieved; thrombosis prophylaxis is continued throughout. Limitation of hip flexion to 90° during the first 6 weeks, and no adduction and forced external rotation to avoid dislocation. Avoidance of sports involving jumping and axial impact loading for 12 months. Radiologic checkups after 3, 6, and 12 months and, thereafter, every 2 years.

Results

Analysis between 2008 and 2011 involved 22 consecutive patients with a total of 23 prostheses; the mean follow-up was 38?±?11 months. Compared to the preoperative evaluation, follow-up yielded a significant improvement in the average Harris Hip Score (82.2?±?8.7 vs. 44.7?±?10.7) and the Merle d’Aubigné Score (14.6?±?1.9 vs. 7.5?±?1.3). Radiological solid osseointegration of the cup was observed in 21 cases; partial radiolucent lines were seen in 2 cases (9?%) in the zones I–III delineated by DeLee and Charnley. In 21 cases (91?%) radiographs confirmed no measurable migration or displacement of the acetabular component and the bone graft was determined to be incorporated on the basis of osseous consolidation within the grafted area in 20 cases (87?%). During follow-up 3 prosthesis (13?%) required revision.     

Defektadaptierte azetabuläre Versorgung mit der Trabecular-Metal-Technologie

Background

The results after acetabular component revision are very heterogeneous, irrespective of the use of established or new components. This could be due to a lack of treatment standards for new revision components. The Trabecular Metal? (TM) revision system, through its modularity, allows for an individual intraoperative reconstruction of the acetabular defect with a single implant system. It was the aim of this study to investigate the results of acetabular revision with the TMT system taking into consideration the utilized components and the acetabular defect.

Methods

A total of 200 consecutive isolated revisions of the acetabular component from 2010 until 2012 were retrospectively analyzed from our institutional database. Of the 200 cases, 114 revisions were performed with a combination of different TMT components (wedge and cup, cup and cage). Aseptic cup failure and revision for any reason were the defined endpoints of this study. The acetabular defects were graded according to the Paprosky classification.

Results

The average patient age was 63.6 ± 14.8 years (range 32–85 years) and the average follow-up was 5.3 ± 0.7 years. The overall revision rate, independent of the utilized components, was 4.4% and the revision rate for aseptic failure of the acetabular component was 2.6%. The revision rate for aseptic loosening for Paprosky type I and II defects was 0% and Paprosky type III and IV defects was 12%.

Conclusions

The modular TMT system shows low revision rates. The modularity of the system allows for a safe and intraoperative adaptation to the individual acetabular defect without the need for extensive preoperative imaging or custom-made implants.

     

Acetabular cortical and cancellous bone density and radiolucent lines after cemented total hip arthroplasty: a prospective study using computed tomography and plain radiography

Introduction

The aim of this prospective study was to evaluate load-transfer mechanisms and stress patterns of periacetabular cortical and cancellous bone after cemented total hip arthroplasty (THA) in vivo using computed tomography (CT) assisted osteodensitometry. In addition we analyzed the efficacy of CT in detecting radiolucent lines around the acetabular component compared to plain radiography.

Materials and methods

Twenty-two cemented acetabular cups were investigated using conventional sequential axial CT scans (Ø 8 days and 26 months post-OP) and plain radiography (Ø 5 days and 40 months post-OP). CT assisted osteodensitometry was used to determine cancellous and cortical bone bone density (BD). Radiolucent lines were evaluated using both CT and plain radiography.

Results

Significant BD loss at the time of follow-up was only detectable ventral to the cup (cortical bone: ?16%, P = 0.001; cancellous bone: ?31%, P = 0.001). The BD changes dorsal and cranial to the cup were not significant. Postoperatively no radiolucent lines were observed in the cement-bone interface by CT, while on plain radiography acetabular lucent lines were seen in 12 out of 22 cases.

Conclusion

CT-osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling: sufficient cancellous and cortical bone stock remained dorsal and cranial to the cup indicative of a balanced load transfer to these regions. CT-osteodensitometry has the potential to become an effective instrument for quality control in THA and the method of choice for in vivo determination of periprosthetic BD. In contrast, plain radiography is more suitable for the early detection of radiolucent lines compared to axial CT scans.

     

The Exeter method—acetabular impaction grafting with cemented reimplantation

Objective

Restoration of acetabular anatomy and biomechanics at revision hip surgery by replacing deficient acetabular bone through impaction of allograft and/or autograft bone chips.

Indications

Aseptic loosening of the socket due to osteolysis, bone loss from infection, iatrogenic bone loss due to implant removal, and in the primary setting protrusio acetabuli, dysplasia and previous acetabular fracture.

Contraindications

Large segmental peripheral acetabular defects which cannot be contained, the presence of untreated infection, unstable acetabular fractures, previous radiotherapy to the affected hip area.

Surgical technique

Sound exposure of the acetabulum with delineation of the bony defect. Creation of a host environment suitable for bone graft and containment of segmental defects using rim mesh or porous augments. Impaction grafting using layered allograft or autograft bone chips of 0.8–1 cm³, packed using hemispherical impactors, followed by cementing of a polyethylene acetabular component with pressurisation.

Postoperative management

Partial weight bearing 6 weeks, modified depending on level of containment and intra-operative findings.

Results

A successful and reproducible technique with survival up to 87?% at 20 years for aseptic loosening in the revision setting.     

Medial placement of the acetabular component in an alumina-on-alumina total hip arthroplasty: a comparative study with propensity score matching

Purpose

In an alumina-on-alumina total hip arthroplasty (THA), recommended with a small inclination angle <45°, the acetabular component (cup) may be positioned more medially to be covered almost completely by host bone. The purpose of this study was to identify the correlating factors and to evaluate the outcomes of medial placement of the cup in patients with alumina-on-alumina THAs.

Methods

Using the propensity score matching with age, gender, body mass index, initial diagnosis, and the length of follow-up as variables, 38 hips with a medialized cup and 38 hips with a non-medialized one were identified from 389 hips in 347 who patients underwent primary alumina-on-alumina THA and followed up for more than 7 years. Clinical and radiological outcomes were compared between the two groups.

Results

Preoperative acetabular medial wall thickness and the cup inclination angle were significantly smaller in the medialization group compared to the non-medialization group. Center edge angle, cup size, and coverage by host bone were not significantly different between the two groups. The hip center of rotation was significantly medialized in the medialization group. The Harris hip scores were not significantly different between the two groups. No component loosening or osteolysis was observed and no revision was required in either groups.

Conclusions

Thin acetabular medial wall and a small inclination angle of the cup were the correlating factors of medial placement of the cup in patients who underwent an alumina-on-alumina THA. Medial placement did not lead to differences in the clinical or radiological outcomes.     

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.