Porous tantalum shells and augments for acetabular cup revisions

Purpose

The purpose of this study was to evaluate early functional results of revision hip arthroplasty with pelvic bone loss revised with porous tantalum (PT) acetabular components.

Methods

Twenty-five consecutive patients (25 hips) with loose acetabular components after total hip arthroplasty with a minimum of Paprosky IIa pelvic bone loss treated with PT cups with and without modular augments were retrospectively reviewed. Clinical outcomes were assessed using Harris hip score, and Western Ontario and McMaster Universities scores. Mean follow-up was 20.5 months and no patient was lost during follow-up.

Results

The average Harris hip score, and Western Ontario and McMaster Universities scores improved from 40 and 36 preoperatively to 79 and 73 postoperatively, respectively. No statistically significant differences in functional outcome scores were found between the group with moderate (Paprosky IIa, b) and severe (Paprosky IIc or more) acetabular bone loss. At the most recent radiographic evaluation, 24 cups demonstrated no lucent lines and 1 cup had lucent lines but remained well fixed. One cup was revised for traumatic dislocation but was found well fixed at open reduction. There were no septic or aseptic failures in this series.

Conclusion

While awaiting longer-term follow-up studies, trabecular metal components show sufficient primary stability and appear suitable for revision hip arthroplasty with acetabular bone loss.     

Modulare Defektrekonstruktion beim Pfannenwechsel mit Abstützschale und metallischen Augmenten

Objective

Restore primary center of rotation and reconstruct extensive bone defects in hip revision surgery with a modular off-label implant combined with antiprotrusion cage and metal augment, thus, achieving improved hip function.

Indications

Large segmental acetabular defects with nonsupportive columns (Paprosky type 3a and 3b) in cup loosening or Girdlestone situation. In case of pelvic discontinuity posterior column-plating is possible.

Contraindications

Persisting hip infection and severe systemic disorders impairing achievement of secondary stability through bony integration of metal augment.

Surgical technique

Posterolateral (if dorsal column plating) or other approach. Remove loose implant and granulation tissue with sufficient exposure of bleeding bone. Size acetabular defect with trial components of augment and appropriate antiprotrusio cage. Fixation of selected metal augment with screws. Fill additional acetabular defects with morsellized bone graft. Open a slot into the ischium to fix the distal flange of the cage. If necessary, bend both flanges according to patient’s anatomy. Enter the ischium with distal flange and gradual impaction of the antiprotrusio ring. Final stabilization of the ring with several screws aiming at the posterior column or the acetabular dome. Inject cement between ring and augment to stabilize the construction and avoid metal wear. Final cement fixation of a polyethylene liner or a dual-mobility cup into the antiprotrusio ring. In pelvic discontinuity with major instability osteosynthesis of the dorsal column can be performed prior to cementation.

Postoperative management

Prophylaxis of periprosthetic infection, DVT and heterotopic ossification. Physical therapy with partial weight bearing (20 kp) for 6 weeks; in discontinuity initial wheel chair mobilization.

Results

Since 2008, 72 off-label implantations of a combined antiprotrusio cage and a Trabecular Metal? Augment were performed. A total of 44 patients (46 operations) were investigated at 38.8 (36–51) months postoperatively. In all, 36 patients had a bone defect according to Paprosky type 3a/b and in 3/4 patients with pelvic discontinuity additional osteosynthesis was performed. The WOMAC score increased from 39.8 (8.7–75) points preoperatively to 57.9 (16.7–97.9) points at follow-up. Migration or failure of implant components was not observed. In 11?% of dislocations and 11?% periprosthetic infections surgical revision was necessary.     

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.     

Bone graft incorporation after revision hip arthroplasty in patients with rheumatoid arthritis, seventy eight revisions using bone allografts with or without metal reinforcements

Purpose

The aim of the study was to assess bone graft incorporation after revision hip arthroplasty in patients with rheumatoid arthritis (RA).

Methods

We report an acetabular reconstruction using impacted, morselized, frozen, radiation sterilized bone allografts in 71 patients suffering from RA. There were sixty-six women and five men at a mean age of 57.5 years. Reconstruction was performed in 78 revision total hip arthroplasties (THAs) for aseptic loosening of acetabular component. The mean follow-up was five years and four months. In 38 cases, a revision was done with use of reinforcement devices.

Results

In four revised hips (10 %) without reinforcement implants, resorption of the allografts was noticed. All Mueller rings and 50 % of unscrews cages (Link, Howmedica) were revised because of aseptic loosening and bone graft resorption. In all of 17 hips with the Burch-Schneider cage, no measurable migration or bone allografts resorption occurred. There were no major general complications.

Conclusions

Acetabular reconstruction with use of morselized, frozen, radiation sterilized bone allografts and the Burch-Schneider cage can be highly successful in managing massive deficiency of acetabular bone stock in revision hip arthroplasty in RA patients.     

Defektadaptierte Versorgung azetabulärer Knochendefekte mit dem 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.

     

Application of temporarily functional antibiotic-containing bone cement prosthesis in revision hip arthroplasty

Purpose

To investigate the clinical outcome of two-stage revision total hip arthroplasty for infected hip arthroplasty using antibiotic-impregnated cement prosthesis.

Materials and methods

Forty-one patients, who suffered from an infection after hip replacement or internal fixation of femoral neck and trochanteric fractures, were treated with a two-stage revision hip arthroplasty and followed up for an average of 37 months. All the patients were implanted with antibiotic-impregnated cement prosthesis as one-stage treatment and were then managed with two-stage revision hip arthroplasty after 12–24 weeks. During the follow-up, Merle d’Aubigné hip score and Harris score were employed for assessment of hip function, and infection recurrence was observed.

Results

According to Merle d’Aubigné hip score, 16 patients (39.2 %) were excellent, 19 (46.3 %) were good, 6 (14.6 %) were moderate, and no bad result and the average score was 15.42. Mean Harris score of preoperation, interval period, and postoperation was 46.7, 66.5, and 92.3, respectively. There was no infection recurrence.

Conclusion

Two-stage revision total hip arthroplasty for infected hip arthroplasty using antibiotic-impregnated cement prosthesis has a satisfying clinical outcome.     

Excessive polyethylene wear and acetabular bone defects from standard use of a hooded acetabular insert in total hip arthroplasty

Purpose

In total hip arthroplasty (THA) the use of a polyethylene (PE) insert with a hooded rim can be considered to reduce dislocation risks. This benefit has to be balanced against the potential introduction of impingement of the femoral component on this rim. We present a case series of early acetabular revisions for excessive PE wear and acetabular bone defects from overuse of such a hooded rim insert.

Material and methods

Twenty-eight patients with 34 consecutive early acetabular revisions were evaluated on failure mechanism. One type of implant was used in all cases. Standard pelvic radiographs and pre-operative CT scans were used to quantify PE wear, implant positioning and acetabular bone defects.

Results

An acetabular revision with impaction grafting was performed in all cases with a mean cup survival of ten years (range 1.3–19.3). No concurrent stem revisions were necessary. Overall implant positioning was adequate with a mean cup inclination of 45° (range 39–57) and anteversion of 25° (range eight to 45). The mean PE wear was 0.24 mm/year (range 0.00–1.17). The mean acetabular bone defect on pelvic CT scans was calculated as 352 mm² (range zero to 1107) and 369 mm² (range zero to 1300) in the coronal and transversal planes, respectively. A hooded acetabular insert was retrieved in all cases and profound PE wear, typically from the posterior hooded rim, was encountered.

Conclusion

The use of hooded acetabular inserts may be considered to improve implant stability intra-operatively. This case series clearly presents that together with these devices, component impingement with concordant complications such as accelerated PE wear may be introduced. Standard use of these stabilizing inserts should thus be avoided.     

Systematic review on outcomes of acetabular revisions with highly-porous metals

Purpose

The purpose of this study was to systematically review the literature and report the clinical and radiographic outcomes of highly-porous acetabular cups in revision settings.

Method

A literature search of four electronic databases of EMBASE, CINAHL-plus, PubMed, and SCOPUS yielded 25 studies reporting the outcomes of 2,083 revision procedures with highly-porous acetabular components. There was lack of high quality evidence (level I and level II studies) and only two studies with level III evidence, while the remainder were all level IV studies. In addition, a majority of the studies had small sample sizes and had short to mid-term follow-up. The mean age of the patients was 65 years (range, 58–72 years) and the mean follow-up was 3.6 years (range, two to six years). Outcomes evaluated were aseptic survivorship, Harris hip scores, migration rates, incidence of peri-acetabular radiolucencies and radiographic restoration of the hip centre.

Results

The mean aseptic survivorship was 97.2 % (range, 80–100 %). The Harris hip scores improved from a mean pre-operative score of 42 points, (range, 29–75 points), to a mean postoperative score of 79 points (range, 69–94 points). The mean incidence of cup migration and prevalence of peri-acetabular radiolucencies was 2.4 % (range, 0–8.8 %) and 4.6 % (range, 0–19 %), respectively, at final follow-up. The vertical hip centre-of-rotation was restored significantly from a mean of 39.2 mm (range, 27.6–50 mm) pre-operatively, to a mean of 24.1 mm (range, 7.4–47 mm), postoperatively.

Conclusion

The short-term clinical and radiographic results of highly-porous metals in revision hip arthroplasty are excellent with a low rate of loosening in the presence of both major and minor bone loss.     

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.     

Mid-term results of revision total hip arthroplasty using the oval-shaped uncemented Trč-Cingr cup

Purpose

The aim of the present study was to introduce a novel oblong revision cup type TC for use in revision total hip arthroplasty (THA), and to evaluate mid-term results in terms of bone tissue remodelling in the immediate area of the implant.

Methods

The results of 31 patients that underwent revision THA between 2004 and 2008 are presented. The mean follow-up interval was 7.1 years (range 5.3–9.3 years, minimum of five years following revision). Osteointegration of the implant and bone tissue remodelling around the implant and ribs were assessed by X-ray and computed tomography (CT).

Results

The average Harris hip score increased from 39.8 to 85.3. Excellent results were achieved in nine patients, good in 16, fair in three and poor in three. According to X-ray results, 25 hips had a well-fixed, bone-ingrown cup and five had a stable fibrous union in the middle and the distal third of the implant. Proximal migration of the cup was noted in one case. Pelvic CT was additionally performed in ten patients. In all cases, we detected bone remodelling in the space between the implant ribs. Kaplan-Maier survivorship of the acetabular components was 94.2 % at 7.1 years.

Conclusions

Our results show that the novel oblong revision cup type TC is relatively simple to implant, and is associated with reliable primary fixation and documented osteointegration and bone remodelling in the immediate area.     

Treatment of high hip dislocation with a cementless stem combined with a shortening osteotomy

Introduction

The purpose of this study was to review the clinical and radiographic outcomes and report the major complications in a group of hips with Crowe type IV developmental dysplasia that underwent reconstruction with a cementless total hip arthroplasty and a transverse subtrochanteric shortening osteotomy fixed with locking compression plate and screws.

Method

Fifteen consecutive patients (21 hips) who had coxarthrosis secondary to Crowe Group IV developmental dysplasia of the hip were treated with a cementless prosthesis and a transverse subtrochanteric osteotomy fixed with locking compression plates at a mean age of 41. The mean follow-up period was 5?years. The acetabular cup was placed in the position of the anatomical hip center in every patient. Subtrochanteric femoral shortening osteotomy was fixed with plates and screws in all patients.

Results

The mean Harris hip score improved from 36.2?±?9.8 points to 90.8?±?2.5 points. Trendelenburg sign was positive in seven hips and two patients complained about continuing anterior thigh pain at the final follow-up. There was no infection. No cases of nonunion were encountered. Two patients had dislocation on early postoperative period (15th and 20th postoperative day). Of these patients, femoral head was changed to 28?mm with stem revision in one patient, and one had acetabular component revision with use of constrained acetabular liner. There was one permanent sciatic nerve palsy. One patient had implant related pain during lying laterally. Plate and screws were removed at postoperative 16th month.

Conclusion

Cementless total hip arthroplasty combined with subtrochanteric osteotomy for the treatment of patients with Crowe Group IV developmental dysplasia of the hip is an effective technique to reduce the hip to its original acetabular location and restore the rotational deformities. Plate and screw fixation is a viable option for a secure and stable fixation of femoral stem after subtrochanteric osteotomy.     

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.     

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.     

Femoral revision with impaction bone grafting and a cemented polished tapered stem

Objective

Biological repair of femoral bone loss using bone impaction grafting. Reconstruction of the centre of rotation of the hip using a cemented stem, the size and offset of which are at the discretion of the surgeon.

Indications

Femoral implant loosening with bone loss.

Contraindications

Infection, neurological disorders, noncompliant patient.

Surgical technique

Extraction of the loose femoral implant, cortical reconstruction using meshes if required, impaction bone grafting with special instruments, cement fixation of a polished tapered stem.

Postoperative management

Individualized period of bed rest and limited weight bearing.

Results

Impaction bone grafting and a cemented polished stem were used to perform 33 femoral reconstructions. After a mean follow-up of 15 years, no femoral reconstruction had to be revised. One unrecognized intraoperative fracture healed after nonsurgical treatment, three postoperative femoral fractures healed after plate fixation with the stem left in situ. The average Harris Hip Score improved from 49 prior to surgery to 85 points thereafter. Kaplan–Meier analysis with femoral revision for any reason as the end point showed a survival rate of 100?%.     

Revision Total Hip Arthroplasty Using an Acetabular Reinforcement Ring With a Hook: A Precise Follow-Up,at Average 11.4 Years,of a Previous Report

Background

This study aims at determining the average long-term result of revision total hip arthroplasty (THA) using the acetabular reinforcement ring with a hook (ARRH) and bone grafting in severe acetabular bony defect. Expected 15-year survival of ARRH in revision THA is included in the study.

Long-term results with the Atlas IIIp elastic cementless acetabular component in total hip replacement

Purpose

Modular cementless elastic acetabular systems have advantages over cemented and hard shell cementless acetabular systems. There are few reports on the medium-term and long-term follow up of this particular type of implant. This study describes our experience with the Atlas IIIp modular acetabular system, which is a thin shell cementless elastic acetabular implant for total hip replacement commercialized under this name in many countries.

Methods

We prospectively followed 244 patients treated with Atlas IIIp acetabular system between 2001 and 2004. Minimum ten year follow up was available for 148 hips (139 patients) from the original cohort of 263 hips (244 patients). One hundred five patients had died from unrelated causes and were excluded from the results. Post-operative and follow up radiographs of patients were assessed; and Harris hip scores were used as clinical outcome. Revision for any reason was defined as the end point for survivorship analysis.

Results

The mean pre-operative Harris hip score was 48 (S.D. 16) and the average post-operative score was 82 (S.D. 12). The mean follow up in our series was 11.5 years, ranging from ten to 13.5 years. Thirteen hips required further surgery in our cohort; of which ten cases required cup revision. The 13-years cumulative implant survival was 91.2 % and the risk of implant revision was 8.8 % at 13 years in 148 hips (139 patients). Kaplan-Meier analysis showed the implant survival rate of 95.2 % at ten years for revision for any reason and 99.4 % for aseptic loosening.

Conclusions

Our clinical experience with this acetabular cup suggests good long-term survival rates that are similar to other cups on the market. The clinical experience in this study shows long-term survival rates that are consistent, acceptable and good results achieved with a low revision rate.Level of evidence: Therapeutic III; therapeutic study.

     

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.