Why revision total hip arthroplasty fails

Comparison of dual-mobility cup and unipolar cup for prevention of dislocation after revision total hip arthroplasty

Background and purpose - Revision total hip arthroplasty (THA) is associated with higher dislocation rates than primary THA. We compared the risk of dislocation within 6 months and all-cause re-revision during the whole study period using either the dual-mobility cup or the unipolar cup. Methods - We used a prospective hospital registry-based cohort including all total and cup-only revision THAs performed between 2003 and 2013. The cups used were either dual-mobility or unipolar; the choice was made according to the preference of the surgeon. 316 revision THAs were included. The mean age of the cohort was 69 (25-98) years and 160 THAs (51%) were performed in women. The dual-mobility group (group 1) included 150 THAs (48%) and the mean length of follow-up was 31 (0-128) months. The unipolar group (group 2) included 166 THAs (53%) and the mean length of follow-up was 52 (0-136) months. Results - The incidence of dislocation within 6 months was significantly lower with the dual-mobility cup than with the unipolar cup (2.7% vs. 7.8%). The unadjusted risk ratio (RR) was 0.34 (95% CI: 0.11-1.02) and the adjusted RR was 0.28 (95% CI: 0.09-0.87). The number of patients needed to treat with a dual-mobility cup in order to prevent 1 case of dislocation was 19. The unadjusted incidence rate ratio for all-cause re-revision in the dual-mobility group compared to the unipolar group was 0.6 (95% CI: 0.3-1.4). Interpretation - Use of a dual-mobility rather than a unipolar cup in revision THA reduced the risk of dislocation within 6 months.

The Extended Direct Anterior Approach for Column Augmentation in the Deficient Pelvis: A Novel Surgical Technique, and Case Series Report

BACKGROUND

Anterior column deficiency of the pelvis may pose a serious threat to the stability of the acetabular component after total hip arthroplasty and, thus, jeopardize the overall success of the procedure.

METHODS

After Institutional Review Board approval, a retrospective review was undertaken to identify all patients undergoing revision total hip arthroplasty with anterior column augmentation through an extended direct anterior approach. Demographics and surgical details were collected, and subjects were followed for a 2-year minimum period to measure patient outcomes and to evaluate for the stability of construct fixation. A novel surgical procedure description was provided and supplemented with an illustrative case example.

RESULTS

At 2 years post augmentation, patients had favorable functional outcomes with radiologic evidence of stable fixation.

CONCLUSION

Proximal extension of the direct anterior approach to the hip can facilitate anterior column access and augmentation to improve stability of the hip reconstruction. This treatment may be an alternative to spanning constructs such as cup-cage constructs and custom implants, affording the potential for long-term biologic fixation. Further investigation into this technique is warranted.

Five-year outcome of proximal femoral endoprosthetic arthroplasty for non-tumour indications

OBJECTIVES

A possible solution for the management of proximal femoral bone loss is a modular femoral endoprosthesis (EPR). Although the outcome of EPRs in tumour surgery has been well described, the outcome of their use in revision hip surgery has received less attention. The aim of this study was to describe the outcome of using EPR for non-neoplastic indications.

METHODS

A retrospective review of 79 patients who underwent 80 EPRs for non-neoplastic indications was performed, including the rates of complication and survival and the mean Oxford Hip Scores (OHS), at a mean of five years post-operatively. The mean age at the time of surgery was 69 years (28 to 93) and the mean number of previous operations on the hip was 2.4 (0 to 17). The most common indications for EPR implantation were periprosthetic joint infection (PJI) (n = 40), periprosthetic fracture (n = 12) and failed osteosynthesis of a proximal femoral fracture or complex trauma (n = 11).

RESULTS

Salvage was achieved in all patients. A total of 25 patients (25 EPRs, 31.6%) had a complication, the most common being infection (n = 9) and dislocation (n = 3). Further surgery was required for 18 EPRs (22%), nine of which were revision procedures. The five year survival of the EPR was 87% (95%CI: 76% to 98%). The mean OHS was 28 (4 to 48). Inferior survival and outcomes were seen in EPRs which were performed for the treatment of infection. However, the eradication of infection was achieved in 33 of the 40 (82.5%) which were undertaken for this indication.

CONCLUSION

We recommend the continued use of proximal femoral EPRs for non-neoplastic indications, including PJI. Cite this article: Bone Joint J 2016;98-B:1463-70.

[Hip dislocation after revision arthroplasty : Risk assessment and treatment strategies]

With a dislocation rate of up to 35% after revision total hip arthroplasty (THA), instability is one of the major causes why this procedure fails. Independent factors for patients at risk are age, sex, and the type of revision needed. The surgical approach, implant choice, and positioning of the components are factors that the surgeon can influence to keep the dislocation rate low. Large femoral heads or double mobility (DM) cups can increase the stability of the joint. After detailed failure analysis, targeted use of different technical innovations enhances stability in revision THA and prevents further revisions.

Direct Anterior Approach: Risk Factor for Early Femoral Failure of Cementless Total Hip Arthroplasty: A Multicenter Study

BACKGROUND

The direct anterior approach for total hip arthroplasty (THA) is marketed with claims of superiority over other approaches. Femoral exposure can be technically challenging and potentially lead to early failure. We examined whether surgical approach is associated with early THA failure.

METHODS

A retrospective review of 478 consecutive early revision THAs performed within 5 years after the primary THAs at 3 academic centers from 2011 through 2014 was carried out. Exclusion criteria resulted in a final analysis sample of 342 early-failure THAs. The surgical approach of the primary operation that was revised, the time to the revision, and the etiology of the failure leading to the revision were documented.

RESULTS

Analysis of the revisions due to early femoral failure showed them to be more common in patients who had undergone the direct anterior approach (57/112; 50.9%) than in those treated with the direct lateral (39/112; 34.8%) or the posterior (16/112; 14.3%) approach (p = 0.001). In multivariate regression analysis controlling for age, sex, laterality, Dorr bone type, body mass index (BMI) at revision, bilateral procedure (yes/no), and femoral stem type, the direct anterior approach remained a significant predictor of early femoral failure (p = 0.007). The majority of early revisions due to instability were associated with the posterior (19/40; 47.5%) or direct anterior (15/40; 37.5%) approach (p = 0.001 for the comparison with the direct lateral approach [6/40; 15.0%]).

CONCLUSIONS

Despite claims of earlier recovery and improved outcomes with the direct anterior approach for THA, our findings indicate that that approach may confer a greater risk of early femoral failure and, along with the posterior approach, confer a greater risk of early instability compared with the direct lateral approach.

LEVEL OF EVIDENCE

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

A Cross-sectional Analysis of Glove Perforation in Primary and Revision Total Hip Arthroplasty

The number of total hip arthroplasties is ever increasing. Literature about glove perforation rates in arthroplasties in India is very scarce. The purpose of our study was to determine the incidence of glove perforation and increasing the awareness of possible glove perforations to decrease the risk of infection. We performed a prospective study in which we tested gloves worn by all scrubbed personnel. A total of 1408 gloves were collected from 42 primary total hip and 13 revision total hip arthroplasties. Incidence of glove perforation was found to be more in revision total hip arthroplasty. We found a greater outer glove perforation rate of about 38.33% as compared to 25 % inner glove perforation rate. Outer glove perforation was recognized 100% of time intraoperatively but inner glove perforation was noted only 17% of time. First assistant recorded highest rate of glove perforation.

Elevated Serum Titanium Level as a Marker for Failure in a Titanium Modular Fluted Tapered Stem

Serum ion concentrations of cobalt and chromium are commonly used to monitor for the development of local metal reactions in metal-on-metal total hip arthroplasties, as well as dual-modular constructs. Although rarely used in clinical practice, elevated serum titanium levels have the ability to indicate a failure with contemporary revision constructs, such as with titanium modular fluted tapered (TMFT) stems. The authors report the case of a 64-year-old man with a TMFT stem after revision total hip arthroplasty for a dual-modular neck construct who had set screw disengagement with subsequent proximal body loosening. The patient's serum cobalt and chromium levels were normal, but he had a markedly elevated serum titanium level, indicating failure of the titanium modular junction. Implant failures at modular junctions in femoral components are well described. Although several different failure mechanisms have been defined, to the authors' knowledge this is the first reported failure of this particular TMFT stem. In addition, this is the first report describing the use of serum titanium levels in identifying a novel failure mechanism. With the popularity of this stem, surgeons should be aware that an elevated serum titanium level may aid in the diagnosis of this unique complication. [Orthopedics. 2016; 39(4):e768-e770.].

Single-component revisions are associated with dislocation after revision total hip arthroplasty at intermediate-term follow-up

PURPOSE

Dislocation is the most frequent complication following revision total hip arthroplasty (THA). Although several risk factors for dislocation in revision THA have been described, many cannot be modified at the time of surgery. Identifying modifiable risk factors for subsequent dislocation after revision THA provides opportunity for orthopedic surgeons to decrease instability.

METHODS

A retrospective analysis of 203 consecutive revision THA procedures performed by a single surgeon with a minimum 2-year follow-up between May 2003 and June 2012 was performed. 2 (1.0%) died and 14 (6.9%) were lost to follow-up leaving 187 (92%) revision procedures in 123 men and 64 women. Univariate and multivariate logistic regression was used to identify risk factors for dislocation.

RESULTS

9 (4.8%) of all patients reviewed experienced a dislocation episode. Of those, 8 (89%) had a single component revised, 6 (67%) were women, and 4 (44%) had a history of recurrent dislocation. 2 of 14 (14%) patients with a constrained liner dislocated. Univariate analysis demonstrated that single-component revisions were at higher risk for dislocation after the surgery (p value = 0.033).

CONCLUSIONS

Identifying modifiable risk factors for dislocation after revision THA provide opportunity to decrease rates of instability. Based on our data, single-component revision THA is a risk factor for subsequent dislocation.

Revision hip arthroplasty using an extensively porous coated stem: medium term results

This is a medium-term, prospective assessment of 56 revision total hip replacements using a.cementless, extensively porous-coated femoral stem.with a mean follow-up of 6 years. All implants demonstrated evidence of bony ingrowth and stable fixation with no cases of loosening, instability, deep infection, stress shielding, subsidence or osteolysis at last follow-up. Complications included two intra-operative fractures, three dislocations, one superficial infection, and one patient with thigh pain. No femoral stems were revised. Good to excellent clinical outcomes were achieved on Harris Hip Score (90% (n = 47/52), Western Ontario and McMaster Universities Index (92% (n = 48/52), and University of California Los Angeles activity score (96% (n=50/52). This supports the use of this system in the revision hip surgery armamentarium.

Midterm Outcomes of Revision Total Hip Arthroplasty Using a Modular Revision Hip System

BACKGROUND

The growth in hip arthroplasty surgery has meant a corresponding escalating revision burden with increasing challenges for the orthopaedic surgeon. The purpose of this study was to review clinical outcomes of a modular revision hip system within a single institution.

METHODS

We retrospectively reviewed a cohort of modular revision hip system stems performed in our institution between January 2005 and October 2012 giving a potential minimum follow-up of 2 years. Clinical outcomes data on complications, Oxford Hip Score (OHS, 0-48) and patient satisfaction were collected. Radiographic outcomes including subsidence were assessed. Implant survival was estimated using Kaplan Meier analysis.

RESULTS

115 stems in 106 patients were identified. All cause survival was 82% (95%CIs: 73%-89%) at 6.1 years; survival excluding infection being 99% (95%CIs: 93%-100%). There was a low incidence of subsidence (seven stems) and no peri-prosthetic fractures. Primary cause of re-revision in this series was re-infection with only one re-revision for mechanical failure. Median Oxford Hip Score at mean follow up 4.1 years (2-9) was 40 (14-48) and 93% of patients reported being satisfied with their revision surgery.

CONCLUSION

This study showed good clinical outcomes and survival using a modular revision stem with low mechanical failure and subsidence. Recurrence of infection remains a challenge in revision surgery.

The impact of bone microstructure on the field distribution of electrostimulative implants

Since the 1980s several methods of electrostimulative techniques have been developed to accelerate bone regeneration during orthopedic treatment. These techniques have proven to provide increased bone formation while curing fractures and bone diseases. The electric parameters, however, are mostly results of empiric research regarding the bone tissue as homogeneous material. Especially cancellous bone, which is the objective of a new electrostimulative total hip revision system, has a porous, inhomogeneous microstructure. The present work investigates numerically the electric field distribution within this tissue using microscopic computer tomography scans of small bone samples. The 3-dimensional X-ray absorption values of these scans are correlated with conductivity values from literature applying different correlation approaches. Compared to electric fields within a homogeneous material strong elevations can be observed within the structures which include most of the bone forming cells.

Functionally deficient mesenchymal stem cells reside in the bone marrow niche with M2-macrophages and amyloid-β protein adjacent to loose total joint implants

We sought to demonstrate whether there is a difference in the local mesenchymal stem cells (MSC) niche obtained from patients undergoing their first total joint replacement surgery versus those patients undergoing a revision surgery for an failing total joint implant. Bone marrow aspirates collected from patients undergoing revision total joint arthroplasty were observed to be less clonal and the expression of PDGFRα, CD51, ALCAM, endoglin, CXCL12, nestin, and nucleostemin were decreased. Revision MSC were also less able to commit to an osteoblast-lineage or an adipocyte-lineage. Further, in revision MSC, OPG, and IL6 expression were increased. Monocytes, derived from revision whole marrow aspirates, were less capable of differentiating into osteoclasts, the cells implicated in the pathologic degradation of bone. Osteoclasts were also not observed in tissue samples collected adjacent to the implants of revision patients; however, the alternatatively activated M2-macrophage phenotype was observed in parallel with pathologic accumulations of amyloid-β, τ-protien and 3-nitrotyrosine. Despite the limited numbers of patients examined, our data suggest that nucleostemin may be a useful functional marker for MSC while the observation of M2-macrophage infiltration around the implant lays the foundation for future investigation into a novel mechanism that we propose is associated with loose total joint implants.

Modeling of an optimized electrostimulative hip revision system under consideration of uncertainty in the conductivity of bone tissue

Since several years, the number of total hip arthroplasty revision surgeries is substantially growing. One of the main reasons for this procedure to become necessary is the loosening or damage of the prothesis, which is facilitated by bone necrosis at the implant-bone interface. Electrostimulation is one promising technique, which can accelerate the growth of bone cells and, therefore, enhance the anchorage of the implant to the bone. We present computational models of an electrostimulative total hip revision system to enhance bone regeneration. In this study, the influence of uncertainty in the conductivity of bone tissue on the electric field strength and the beneficial stimulation volume for an optimized electrode geometry and arrangement is investigated. The generalized polynomial chaos technique is used to quantify the uncertainty in the stimulation volumes with respect to the uncertain conductivity of cancellous bone, bone marrow, and bone substitute, which is used to fill defective areas. The results suggest that the overall beneficial stimulation areas are only slightly sensitive to the uncertainty in conductivity of bone tissue. However, in the proximity of tissue boundaries, larger uncertainties, especially in the transition between beneficial and understimulation areas, can be expected.

Phase stability and biological property evaluation of plasma sprayed hydroxyapatite coatings for orthopedic and dental applications

In this work we have investigated the effects of strontium (Sr) dopant on in vitro protein release kinetics and in vivo osteogenic properties of plasma sprayed hydroxyapatite (HA) coatings, along with their dissolution behavior. Plasma sprayed HA coatings are widely used in load-bearing implants. Apart from osseointegration, the new generation of HA coating is expected to deliver biomolecules and/or drugs that can induce osteoinduction. This paper reports the preparation of crystalline and amorphous HA coatings on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray, and their stability at different solution pH. Coatings prepared at 110 mm working distance from the nozzle showed an average Ca ion release of 18 and 90 ppm in neutral and acidic environments, respectively. Decreasing the working distance to 90 mm resulted in the formation of a coating with less crystalline HA and phases with higher solubility products, and consequently higher dissolution over 32 days. A 92% release of a model protein bovine serum albumin (BSA) in phosphate buffer with pH of 7.4 was measured for Sr-doped HA (Sr-HA) coating, while only a 72% release could be measured for pure HA coating. Distortion of BSA during adsorption on coatings revealed a strong interaction between the protein and the coating, with an increase in α-helix content. Osteoid formation was found on Sr-HA implants as early as 7 weeks post implantation compared to HA coated and uncoated Ti implants. After 12 weeks post implantation, osteoid new bone was formed on HA implants; whereas, bone mineralization started on Sr-HA samples. While no osteoid was formed on bare Ti surfaces, bone was completely mineralized on HA and Sr-HA coatings after 16 weeks post implantation. Our results show that both phase stability and chemistry can have a significant influence toward in vitro and in vivo response of HA coatings on Ti implants.

Can Dual Mobility Cups prevent Dislocation in All Situations After Revision Total Hip Arthroplasty?

The outcome of a single design of dual mobility cup was prospectively evaluated in a continuous series of 994 revision THAs with respect to dislocation and intra-prosthetic dislocation (IPD). At a 7.3-year mean follow-up, the dislocation rate was 1.5% and the IPD rate was 0.2%. The 2 IPD occurred in acetabular-only revisions and were related to a poor head-to-neck ratio with early impingement and wear at the polyethylene mobile component chamfer. Dual mobility cups demonstrated a low dislocation rate in revision THA but did not compensate for potential perioperative technical errors. In addition, IPD did not appear to be a concern with respect to the benefit in term of instability prevention though caution is advised in acetabular-only revision associated with a poor head-to-neck ratio.

LEVEL OF EVIDENCE

Therapeutic study-Level IV.

Metal-on-conventional polyethylene total hip arthroplasty bearing surfaces have a higher risk of revision than metal-on-highly crosslinked polyethylene: results from a US registry

BACKGROUND

Although studies have reported lower radiological wear in highly crosslinked polyethylene (HXLPE) versus conventional polyethylene in total hip arthroplasty (THA), there is limited clinical evidence on the risk of revision of these polyethylene THA bearing surfaces.

QUESTIONS/PURPOSES

We asked: (1) Do primary THAs with a metal-on-conventional polyethylene bearing surface have a higher risk of revision (all-cause or aseptic) than metal-on-HXLPE? (2) Is the risk of revision (all-cause or aseptic) higher for conventional polyethylene versus HXLPE when the effect of femoral and acetabular components is controlled for in prosthesis-specific analyses?

METHODS

The Kaiser Permanente's Total Joint Replacement Registry was used to identify metal-on-conventional polyethylene and metal-on-HXLPE primary THAs (N = 26,823) performed between April 2001 and December 2011. The registry has 95% voluntary participation and 8% were lost to followup during the 10-year study period. Endpoints of interest were all-cause and aseptic revisions. Descriptive statistics and marginal Cox regression models with propensity score adjustments were applied to compare risk of revision for metal-on-conventional polyethylene versus metal-on-HXLPE THAs and to evaluate two specific manufacturers' hip implant designs while controlling for femoral and acetabular components. Of the 26,823 THAs included in the study, 1815 (7%) were metal-on-conventional polyethylene and 25,008 (93%) were metal-on-HXLPE.

RESULTS

At 7 years followup, the cumulative incidence of revision was 5.4% (95% confidence interval [CI], 4.4%-6.7%) for metal-on-conventional and 2.8% (95% CI, 2.6%-3.2%) for metal-on-HXLPE. There was a higher adjusted risk of all-cause (hazard ratio [HR], 1.75; 95% CI, 1.37-2.24; p < 0.001) and aseptic (HR, 1.91; 95% CI, 1.46-2.50; p < 0.001) revisions among metal-on-conventional polyethylene bearing surface hips compared with metal-on-HXLPE. Results were similar within manufacturer hip designs with the same femoral and acetabular components. Conclusions Metal-on-conventional polyethylene THA bearing surfaces have a higher risk of revision compared with metal-on-HXLPE bearing surfaces. Clinicians should consider the use of HXLPE when using a polyethylene bearing in THA.

LEVEL OF EVIDENCE

Level II, cohort study.

Revisions of monoblock metal-on-metal THAs have high early complication rates

BACKGROUND

A relatively high percentage of monoblock metal-on-metal total hip arthroplasties (THAs) undergo early revision. Revision of these THAs poses challenges unique to this implant type. The early complications after these revisions remain unreported as do the clinical and demographic factors associated with these complications.

QUESTIONS/PURPOSES

We describe (1) the frequency of early complications after revision of monoblock metal-on-metal THA; and (2) the clinical and demographic factors associated with complications.

METHODS

A review of our institution's total joint registry identified 107 patients who underwent 114 revisions of monoblock metal-on-metal THAs. Mean patient age at revision was 60 years (range, 17-84 years), and 65% of the patients were women. Mean followup after revision was 14 months (range, 0-122 months). Revision diagnoses included metallosis (51%), aseptic loosening (27%), infection (7%), pain (6%), malposition (4%), instability (3%), iliopsoas impingement (2%), and periprosthetic fracture (1%). Major complications (instability, infection, aseptic loosening, and wound complications) were documented and included in the analysis. Minor postoperative complications such as urinary tract infection were excluded.

RESULTS

Twenty-three of 114 procedures (20%) involved at least one early complication after revision of monoblock metal-on-metal THA with 18 (16%) undergoing at least one additional subsequent surgery. The most common complications included aseptic loosening (6%), deep infection (6%), dislocation (4%), and acetabular fracture (3%). Patients who sustained a complication after revision surgery were older on average than those who did not (66 years versus 58 years, p=0.003). There were no differences in complication rate with respect to sex, time to revision, or revision diagnosis.

CONCLUSIONS

Complications and reoperations occur frequently after revision for failed monoblock metal-on-metal THA (20% and 16%, respectively), and older patients appear to be at greater risk for complications after these revisions. Aseptic loosening, deep infection, and instability are all of great concern after revision and surgeons should be aware of these potential complications when undertaking revision of these THAs.

LEVEL OF EVIDENCE

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

Large diameter femoral heads: is bigger always better?

Dislocation remains among the most common complications of, and reasons for, revision of both primary and revision total hip replacements (THR). Hence, there is great interest in maximising stability to prevent this complication. Head size has been recognised to have a strong influence on the risk of dislocation post-operatively. As femoral head size increases, stability is augmented, secondary to an increase in impingement-free range of movement. Larger head sizes also greatly increase the 'jump distance' required for the head to dislocate in an appropriately positioned cup. Level-one studies support the use of larger diameter heads as they decrease the risk of dislocation following primary and revision THR. Highly cross-linked polyethylene has allowed us to increase femoral head size, without a marked increase in wear. However, the thin polyethylene liners necessary to accommodate larger heads may increase the risk of liner fracture and larger heads have also been implicated in causing soft-tissue impingement resulting in groin pain. Larger diameter heads also impart larger forces on the femoral trunnion, which may contribute to corrosion, metal release, and adverse local tissue reactions. Alternative large bearings including large ceramic heads and dual mobility bearings may mitigate some of these risks, and several of these devices have been used with clinical success.

Uncertainty quantification of the optimal stimulation area in an electro-stimulative hip revision system

Electro-stimulative hip revision systems accelerate the bone growth around the implant and are capable of reducing the number of side effects such as aseptic implant loosening. A computational model was developed to determine the optimal electrode arrangement for such a system, which is currently under development. The optimization process depends on the electrical properties of bone material and the used bone substitute, which are subject to uncertainty in literature and its production process, respectively. To quantify the influence of these uncertain parameters on the optimal stimulation ratio (OSR), the computationally effective non-intrusive polynomial chaos technique was applied. The results indicate that the conductivity of bone substitute is most sensitive to the OSR, while its uncertainty was comparatively small compared to that of the uncertain parameters.

Relative head size increase using an anatomic dual mobility hip prosthesis compared to traditional hip arthroplasty: impact on hip stability

Smaller head sizes and head/cup ratios make cups smaller than 50mm and larger than 58mm, more prone to dislocation. Using computer modeling, we compared average head sizes and posterior horizontal dislocation distance (PHDD) in two 78-patient matched cohorts. Cup sizes were small (≤50mm) or large (≥58mm). The control cohort had conventional fixed bearing prostheses, while the experimental cohort had anatomical dual mobility (ADM) hip prostheses. ADM cups have larger average head sizes and PHDD than traditional fixed bearing prostheses by 11.5mm and 80% for cups ≤50mm, and 16.3mm and 90% for cups ≥58mm. Larger head sizes and increased head/cup ratio may allow the ADM prosthesis to reduce the incidence of dislocation.

Cementless dual-mobility cup in total hip arthroplasty revision

PURPOSE

Dislocation is a frequent complication in total hip arthroplasty (THA) revision. Cup fixation is the second concern. In order to know outcomes at two years, we prospectively followed a continuous series of 78 patients to demonstrate that cementless dual-mobility cup (DMC) used in revision THA is safe as regards dislocation risk and bone fixation.

METHOD

We enrolled 78 consecutive patients (79 cases) in a prospective study. Mean interval between index surgery and revision was 12.9 years. Mean age at revision was 75.5 years. Two types of cementless DMC were used: a standard DMC in 68 cases with low-grade bone defect (Paprosky grade 1 and 2), and a specific design reconstruction DMC in 11 cases with severe bone loss (Paprosky grade 3).

RESULTS

At two years of follow-up, 68 patients were reviewed; four were lost to follow-up., and six patients were deceased. We identified three types of situations at risk:standard risk (33 cases), Paprosky grade 1 or 2; medium risk (37 cases), revision for recurrent instability (21), periprosthetic fractures (14) or severe loosening Paprosky grade 3 without femorotomy (2); high risk (nine cases), revision for severe loosening with a femorotomy. One (1.3%) patient dislocated her hip at one month without recurrence. Revision rate for dislocation was 0%; two (2.7%) early mechanical failures occurred.

CONCLUSION

Considering outcomes of this series, cementless DMC can be suggested in THA revision surgery.

Variation in hospital-level risk-standardized complication rates following elective primary total hip and knee arthroplasty

BACKGROUND

Little is known about the variation in complication rates among U.S. hospitals that perform elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures. The purpose of this study was to use National Quality Forum (NQF)-endorsed hospital-level risk-standardized complication rates to describe variations in, and disparities related to, hospital quality for elective primary THA and TKA procedures performed in U.S. hospitals.

METHODS

We conducted a cross-sectional analysis of national Medicare Fee-for-Service data. The study cohort included 878,098 Medicare fee-for-service beneficiaries, sixty-five years or older, who underwent elective THA or TKA from 2008 to 2010 at 3479 hospitals. Both medical and surgical complications were included in the composite measure. Hospital-specific complication rates were calculated from Medicare claims with use of hierarchical logistic regression to account for patient clustering and were risk-adjusted for age, sex, and patient comorbidities. We determined whether hospitals with higher proportions of Medicaid patients and black patients had higher risk-standardized complication rates.

RESULTS

The crude rate of measured complications was 3.6%. The most common complications were pneumonia (0.86%), pulmonary embolism (0.75%), and periprosthetic joint infection or wound infection (0.67%). The median risk-standardized complication rate was 3.6% (range, 1.8% to 9.0%). Among hospitals with at least twenty-five THA and TKA patients in the study cohort, 103 (3.6%) were better and seventy-five (2.6%) were worse than expected. Hospitals with the highest proportion of Medicaid patients had slightly higher but similar risk-standardized complication rates (median, 3.6%; range, 2.0% to 7.1%) compared with hospitals in the lowest decile (3.4%; 1.7% to 6.2%). Findings were similar for the analysis involving the proportion of black patients.

CONCLUSIONS

There was more than a fourfold difference in risk-standardized complication rates across U.S. hospitals in which elective THA and TKA are performed. Although hospitals with higher proportions of Medicaid and black patients had rates similar to those of hospitals with lower proportions, there is a continued need to monitor for disparities in outcomes. These findings suggest there are opportunities for quality improvement among hospitals in which elective THA and TKA procedures are performed.

Acetabular reconstruction using a Kerboull cross-plate, structural allograft and cemented dual-mobility cup in revision THA at a minimum 5-year follow-up

The current study aimed to evaluate the outcome of a continuous and prospective series of 61 revision THAs with AAOS grade III and IV acetabular bone defect reconstruction using a Kerboull cross-plate, structural allograft and cemented dual mobility cup (Saturne, Amplitude, Valence, France). At a 7.5-year mean follow-up, no instability was reported after revision. In addition, no failure of the acetabular reconstruction was observed in 98% of the patients with complete allograft osseointegration and no evidence of mechanical rupture of the Kerboull cross-plate and/or loosening of the cemented dual mobility cup. In conclusion, such reconstruction technique demonstrated excellent results at mid-term follow-up in terms of prevention of instability after revision, restoration of the acetabular bone stock, and stable cemented fixation of the dual mobility cup.

The value of computed tomography based navigation in revision total hip arthroplasty

PURPOSE

This study investigates the accuracy of a computed tomography (CT)-based navigation system for accurate acetabular component placement during revision total hip arthroplasty (THA).

METHODS

We performed a retrospective review of 30 hips in 26 patients who underwent cementless revision THA using a CT-based navigation system; the control group consisted of 25 hips in 25 patients who underwent cementless primary THA using the same system. We analysed the deviation of anteversion and inclination angles among the pre-operative plan, intra-operative records from the navigation system and data from postoperative CT scans.

RESULTS

There were no significant differences between groups (P < 0.05) in terms of mean deviation between pre-operative planning and postoperative measurements or between intraoperative records and postoperative measurements.

CONCLUSION

CT-based navigation in revision THA is a useful tool that enables the surgeon to implant the acetabular component at the precise angle determined in pre-operative planning.

Predictive outcomes of revision total hip replacement--a consecutive series of 1176 patients with a minimum 10-year follow-up

The burden of revision total hip replacement (THR) surgery is increasing. With an increasing life expectancy and younger age of primary surgery this trend is set to continue. There are few data on the long-term outcome of revision THR. This retrospective study of 1176 consecutive revision THRs with a minimum 10-year follow-up from a University Teaching Hospital was undertaken to review implant survival and patient reported outcomes. Mean follow-up was 11 years with implant survival at 10 years of 82% (CI: 80-85). Implant survival varied between 58% (unexplained pain) to 84% (aseptic loosening) depending on the indication for revision surgery. Positive predictors of survival were age greater than 70 at the time of surgery (p=0.011), revision for aseptic loosening (p<0.01) and revision of both components or just the acetabular component (p<0.01). At the last review, mean Oxford Hip Score (OHS) was 34 (SD: 11.3) and 92% of the living patients with unrevised hips were satisfied with the outcome of revision surgery. This long term study has demonstrated that positive predictors of survival and outcome of revision THR surgery are age greater than 70 years, revision for aseptic loosening and component revision. This should aid surgeons in their counselling of patients prior to surgery.

Impaction grafting of the acetabulum with ceramic bone graft substitute mixed with femoral head allograft: high survivorship in 43 patients with a median follow-up of 7 years: a follow-up report

BACKGROUND AND PURPOSE

Restoration of bone stock at revision hip surgery remains a challenge. Alternative graft materials with suitable mechanical properties for impaction grafting have been sought due to issues with infection, antigenicity, cost, and availability of allograft. We have previously presented good short-term results of the use of BoneSave, a biphasic porous ceramic bone graft substitute, consisting of sintered 80% tricalcium phosphate and 20% hydroxyapatite, in a 50:50 mix with femoral head allograft. We now present the medium-term results.

METHODS

We conducted a retrospective review of a cohort of 43 consecutive patients undergoing impaction grafting of contained acetabular defects by multiple surgeons at a single center. 34 patients received uncemented acetabular components and 9 received cemented components. Patients were followed up radiographically and with the self-reported satisfaction scale (SAPS), Oxford hip score (OHS), and the Short-Form 12 (SF12) health survey. Kaplan-Meier survivorship analysis was performed with revision of the acetabular component, revision of any part of the construct, and reoperation as endpoints.

RESULTS

The fate of all cases was known. Median follow-up of the surviving patients was 80 (69-106) months. 15 patients died during the follow-up period, 14 with their construct in situ. The survivorship of the grafted acetabulum and acetabular component was 94% (95% CI: 99-78) at 7 years. 1 patient had been revised for aseptic loosening of the acetabulum and 1 for deep infection. The mean OHS was 31 (SD 12), the mean SF12 physical-component score (PCS) was 38 (SD 13), the median SAPS was 83 (0-100), and the median SF12 mental-component score (MCS) was 55 (23-65). The graft material became incorporated in all 3 zones of the acetabulum in 23 out of 24 cases that had complete radiographic follow-up.

INTERPRETATION

These medium-term results show that BoneSave is a reliable material for impaction grafting of the acetabulum when used in conjunction with femoral head allograft.

Dual mobility cups for preventing early hip arthroplasty dislocation in patients at risk: experience in a county hospital

Dislocation remains a major concern after hip arthroplasty. We asked whether dual mobility cups (DMC) would improve early hip stability in patients with high risk of dislocation. We followed 34 patients (21 females, 13 males) treated between 2009 and 2012 with cemented DMC for hip revisions caused recurrent hip prosthetic dislocation or as a primary procedure in patients with high risk of instability. Functional outcome and quality of life were evaluated using Harris Hip Score and EQ-5D respectively. We found that the cemented DMC gave stability in 94%. Seven patients (20%) were re-operated due to infection. One patient sustained a periprosthetic fracture. At follow-up (6 to 36 months, mean 18), the mean Harris hip score was 67 (standard deviation: 14) and mean EQ-5D was 0.76 (standard deviation: 0.12). We concluded that treating patients with high risk of dislocation with DMC can give good stability. However, complications such as postoperative infection can be frequent and should be managed carefully.

Cementation of a dual-mobility acetabular component into a well-fixed metal shell during revision total hip arthroplasty: a biomechanical validation

Cementation of polyethylene (PE) liners into well-fixed metal shells has become a popular option during revision total hip arthroplasty (THA) particularly for older and frail patients. Although dramatic results were reported with dual-mobility acetabular components to manage hip instability during revision THA, no study evaluated the fixation strength of the cementation of dual-mobility components into well-fixed metal shells. Eight dual-mobility and eight all-PE components were cemented into a metal shell with a uniform 2- to 3-mm cement mantle. The cemented fixation strength was evaluated using lever-out and torsion testing. The interface at which failure occurred was determined. Lever-out testing showed that dual-mobility components failed at significantly higher maximum moment than the all-PE components. No direct comparison could be performed with torsion testing due to early failure of the all-PE component itself before failure of the cement fixation. However, the maximum moments measured were dramatically higher than the in vivo frictional moments classically reported in THA. In addition, failure was always observed at the metal shell/cement interface whenever it did occur. In conclusion, a dual-mobility acetabular component cemented into a well-fixed metal shell could constitute a biomechanically acceptable alternative to acetabular shell removal or PE liner cementation while simultaneously preventing instability of the THA revision. Clinical studies are warranted.

Which implant is best after failed treatment for pathologic femur fractures?

BACKGROUND

Successful treatment of pathologic femur fractures can preserve a patient's independence and quality of life. The choice of implant depends on several disease- and patient-specific variables; however, its durability must generally match the patient's estimated life expectancy. Failures do occur, however, it is unclear which implants are associated with greater risk of failure.

QUESTIONS/PURPOSES

We evaluated patients with femoral metastases in whom implants failed to determine (1) the rate of reoperation; (2) the timing of and most common causes for failure; and (3) incidence of perioperative complications and death.

METHODS

From a prospectively collected registry, we identified 93 patients operated on for failed treatment of femoral metastases from 1990 to 2010. We excluded five patients who subsequently underwent amputations leaving 88 who underwent salvage procedures. These included intramedullary nails (n = 11), endoprostheses (n = 61), and plate fixation (n = 16). The primary outcome was reoperation after salvage treatment.

RESULTS

Seventeen of the 88 patients (19%) required subsequent reoperation a median of 10 months (interquartile range, 4-14) from the time of salvage surgery: 15 for material failure, one for local progression of tumor, and one for a combination of these. Five patients died within 4 weeks of surgery. Although perioperative complications were higher in the endoprosthesis group and dislocations occurred, overall treatment failures after salvage surgery were lower in the that group (four of 61) compared the group with plate fixation (eight of 16) and intramedullary nail groups (five of 11).

CONCLUSIONS

Despite relatively common perioperative complications, salvage using endoprostheses may be associated with fewer treatment failures as compared with internal fixation.

LEVEL OF EVIDENCE

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

Risk factors for dislocation after revision total hip arthroplasty

BACKGROUND

Despite dislocation being the most frequent complication after revision THA, risk factors for its occurrence are not completely understood.

QUESTIONS/PURPOSES

We therefore (1) determined the overall risk of dislocation after revision THA in a large series of revision THAs using contemporary revision techniques, (2) identified patient-related risk factors predicting dislocation, and (3) identified surgical variables predicting dislocation.

METHODS

We performed 1211 revision THAs between June 2004 and October 2010 in 576 women and 415 men who had a mean age of 64.7 years (range, 25-95 years) at time of surgery. Forty-six (4%) were lost to followup and 13 died (1%), leaving 1152 hips followed for a minimum of 90 days (mean, 2 years; range, 90 days to 7.1 years). Multivariate logistic regression was performed to identify risk factors for dislocation. The model was also tested on patients followed for a minimum 1 year to assess any difference in longer followup.

RESULTS

One hundred thirteen patients dislocated over the followup period (9.8%). Factors that were different between patients who dislocated and those who remained stable included a history of at least one previous dislocation (odds ratio [OR] = 2.673), abductor deficiency (OR = 2.672), and Paprosky acetabulum class (OR = 1.522). Use of a constrained liner (OR = 0.503) and increased femoral head size (OR = 0.942) were protective against dislocation, while with longer followup a constrained liner was no longer significant.

CONCLUSIONS

Dislocation remains a common problem after revision THA. Identifying these risk factors can assist in patient education and surgical planning. Recognition of these risk factors in both patient type and surgical strategy is important for the surgeon performing revision THA and for minimizing these risks.

LEVEL OF EVIDENCE

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

Revision total hip arthroplasty in younger patients: indications, reasons for failure, and survivorship

Increasing numbers of total hip arthroplasty (THA) procedures are being performed on younger patients, and the incidence of revision THA in this population is also increasing. The goals of our retrospective study were to survey the surgical indications and reasons for failure and survivorship of revision THA in patients aged < 50 years. We identified 139 cases of revision THA performed over a 6-year period in patients aged < 50 years. The most common reason for revision was aseptic loosening, followed by acetabular liner wear with or without osteolysis. We found an overall 10-year survivorship of 76%. When survivorship was stratified by the indication for revision surgery, revision for wear demonstrated the best 10-year survivorship, while revision for instability or infection exhibited poor survivorship.

Is routine mid-term total hip arthroplasty surveillance beneficial?

BACKGROUND

Routine followup of patients after primary or revision THA is commonly practiced and driven by concerns that delays in identifying early failure will result in more complicated or more costly surgical interventions. Although mid-term followup (4-10 years) has been performed to follow cohorts of patients, the benefit of observing individual patients regardless of symptoms has not been established.

QUESTIONS/PURPOSES

We determined (1) the reasons patients with THA return for mid-term followup, (2) the treatment recommendations and interventions occurring as a result of mid-term followup, and (3) how frequently revision surgery is recommended for asymptomatic and symptomatic patients at mid-term followup.

METHODS

We retrospectively identified 501 patients (503 hips) who returned for followup at least 4 years (mean, 5 years; range, 4-10.9 years) after their primary or revision THA. We recorded their reasons for followup and treatment recommendations, including those for revision surgery, at mid-term followup.

RESULTS

Fifty-three percent of patients returning for routine followup had no symptoms, 31% reported an unrelated musculoskeletal concern, and 19% had symptoms from their primary THA (15%) or revision THA (32%). Sixty-nine percent of symptomatic patients and 10% of asymptomatic patients received treatment recommendations, with physical therapy as the most frequent intervention (74%). Revision surgery was recommended for 6% of symptomatic and 0.6% of asymptomatic patients.

CONCLUSIONS

Although routine surveillance may identify rare, asymptomatic patients with arthroplasty failure, it is much more likely to result in recommendations for nonoperative management during early followup.

LEVEL OF EVIDENCE

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

Femoral bone is preserved using cemented polished stems in young patients

BACKGROUND

Techniques that ensure femoral bone preservation after primary THA are important in younger patients who are likely to undergo revision surgery.

QUESTIONS/PURPOSES

We examined femoral stem survival, bone deficiency at revision arthroplasty, and radiographic bone loss in hips implanted with a cemented polished double-taper stem in a cohort of patients younger than 55 years.

METHODS

We reviewed 197 hips (median patient age, 47 years; range, 16-54 years) after a minimum followup of 2 years (median, 7 years; range, 2-19 years) since primary THA. Clinically, we determined survival to major and minor stem revision and cases of bone deficiency requiring a long stem or impaction bone grafting or created by the need for femoral osteotomy at revision arthroplasty. Radiographically, we assessed stem loosening, femoral osteolysis, and femoral bone deficiency.

RESULTS

Stem survival to major revision for aseptic loosening was 100% at 13 years and for any reason was 97% (95% CI, 93-100%). At revision of seven stems, a long stem was used in one hip, a total femoral replacement in one hip and impaction bone grafting in one hip. No femoral osteotomies were required. Bone was preserved in four hips by cement-within-cement stem exchange. No stems were radiographically loose. Proximal osteolysis was present in 11% of femurs. Femoral bone deficiency was graded as Paprosky Type I (97%) or II (3%) and Endo-Klinik Grade 0 (79%) or I (21%).

CONCLUSIONS

Cemented polished taper stems have high survival at 13 years in young patients and enable femoral bone preservation for subsequent revision.

LEVEL OF EVIDENCE

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

The use of abduction bracing for the prevention of early postoperative dislocation after revision total hip arthroplasty

One potential strategy to decrease the risk of dislocation after revision total hip arthroplasty (THA) is the use of an abduction brace to limit flexion and adduction. The purpose of this study was to compare the dislocation rate after revision THA between patients treated with or without an abduction brace. Data were obtained from 1211 revision THAs performed in 610 women and 518 men who had a mean age of 64.7 years (range, 22-95 years) and were followed up for a minimum of 90 days. Five hundred two patients were braced, whereas 650 were not. The 90-day dislocation rate among patients who wore a brace was 5.2% compared with 5.7% in the nonbrace group (P = .70). Multivariate regression found no benefit to bracing (P = .37), while controlling for factors found to significantly affect dislocation rate in this population. Our data do not support the routine use of an abduction brace to aid in the prevention of dislocation.

A prospective analysis of glove perforation in primary and revision total hip and total knee arthroplasty

Literature in regard to glove perforation rates in revision total joint arthroplasty (TJA) is scarce. Our purpose was to determine the incidence of perforation in revision TJA. Gloves from all scrubbed personnel were tested based on the American Society for Testing and Materials. A total of 3863 gloves were collected from 58 primary and 36 revision arthroplasty cases. Surgeons had a 3.7% outer-glove perforation rate in primary TJA compared with 8.9% in revision TJA. When both gloves were perforated, the outer-glove perforation was recognized intraoperatively 100% of the time, and the inner-glove perforation was noted only 19% of the time. The surgeon has the highest rate of glove perforation. Outer-glove perforations should prompt careful inspection of the inner glove.

The double-mobility acetabular component in revision total hip replacement

We present our experience with a double-mobility acetabular component in 155 consecutive revision total hip replacements in 149 patients undertaken between 2005 and 2009, with particular emphasis on the incidence of further dislocation. The mean age of the patients was 77 years (42 to 89) with 59 males and 90 females. In all, five patients died and seven were lost to follow-up. Indications for revision were aseptic loosening in 113 hips, recurrent instability in 29, peri-prosthetic fracture in 11 and sepsis in two. The mean follow-up was 42 months (18 to 68). Three hips (2%) in three patients dislocated within six weeks of surgery; one of these dislocated again after one year. All three were managed successfully with closed reduction. Two of the three dislocations occurred in patients who had undergone revision for recurrent dislocation. All three were found at revision to have abductor deficiency. There were no dislocations in those revised for either aseptic loosening or sepsis.

These results demonstrate a good mid-term outcome for this component. In the 29 patients revised for instability, only two had a further dislocation, both of which were managed by closed reduction.

[What can be done when hip prostheses fail? : New trends in revision endoprosthetics]

Revision surgery after total hip arthroplasty is increasing steadily in numbers. These procedures demand high performance from both the treating surgeon as well as the implants used. Novel developments from basic research and industrial partners extend the possibilities for treating affected patients. This article gives an overview of the state of the art in revision hip arthroplasty: new techniques and trends are outlined and presented.

Tantalum augments for Paprosky IIIA defects remain stable at midterm followup

BACKGROUND

Initial reports with short-term followup of porous tantalum acetabular components and augments for Paprosky IIIA acetabular defects demonstrate high hip scores, low rates of aseptic loosening, and low rates of complications. However, longer-term followup with a larger cohort is needed to determine the durability of these reconstructions.

QUESTIONS/PURPOSES

We therefore determined the functional scores, rates of aseptic loosening, and complications in patients with Paprosky IIIA acetabular defects treated with porous tantalum acetabular components and augments.

METHODS

We retrospectively reviewed 37 acetabular revisions in 36 patients (one patient with bilateral revisions) treated with a porous tantalum acetabular component and augment. All patients had defects classified as Type IIIa using the system of Paprosky et al. Harris hip scores were obtained and radiographic examination was performed before surgery and through most recent followup. The minimum followup was 26 months (mean, 60 months; range, 26-106 months).

RESULTS

One patient developed aseptic loosening of the acetabular reconstruction requiring revision; seven other patients required further surgery for periprosthetic femoral fracture (two), acute infection (three), and recurrent dislocation (two). Thirty-five of 37 hips had no or occasional pain at final followup. Mean Harris hip scores improved from 33.0 preoperatively (range, 12.6-58.7) to 81.5 postoperatively (range, 27.0-99.8).

CONCLUSIONS

Although the complication rate requiring further surgery was considerable, most patients with these reconstructions had pain relief and reasonable function with low rates of loosening at midterm followup.

LEVEL OF EVIDENCE

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

The Frank Stinchfield Award: Dislocation in revision THA: do large heads (36 and 40 mm) result in reduced dislocation rates in a randomized clinical trial?

BACKGROUND

Dislocation after revision THA is a common complication. Large heads have the potential to decrease dislocation rate, but it is unclear whether they do so in revision THA.

QUESTIONS/PURPOSES

We therefore determined whether a large femoral head (36 and 40 mm) resulted in a decreased dislocation rate compared to a standard head (32 mm).

METHODS

We randomized 184 patients undergoing revision THA to receive either a 32-mm head (92 patients) or 36- and 40-mm head (92 patients) and stratified patients by surgeon. The two groups had similar baseline demographics. The primary end point was dislocation. Quality-of-life (QOL) measures were WOMAC and SF-36. The mean followup for dislocation was 5 years (range, 2-7 years); the mean followup for QOL was 2.2 years (range, 1.6-4 years).

RESULTS

In the 36- and 40-mm head group, the dislocation rate was 1.1% (one of 92) versus 8.7% (eight of 92) for the 32-mm head. There was no difference in QOL outcomes between the two groups.

CONCLUSIONS

Our observations confirm a large femoral head (36 or 40 mm) reduces dislocation rates in patients undergoing revision THA at short-term followup. We now routinely use large heads with a highly crosslinked polyethylene acetabular liner in all revision THAs.

LEVEL OF EVIDENCE

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

Identification of widely applicable configurations for the electrostimulative total hip revision system

Since the 1980s electrostimulation is used to accelerate the healing of fractures and bone defects. In prior works this effect has been implemented in a numerical model of an electrostimulative hip revision cup which was optimized using a multi-objective evolutionary algorithm. The aim of our simulations is to design an implant which provides optimal electric fields in the acetabular region enhancing the reconstruction of the pelvic bone in such way as to improve the fixation of the prosthesis in the surrounding bone. In the present work we will show that this multi-objective algorithm can also be used to identify a small amount of configurations of the implant that will be able to stimulate a wide range of pelvic bones with different acetabular defects.

Bone graft substitutes in hip revision surgery: a comprehensive overview

INTRODUCTION

Total hip replacement is increasingly used to treat diseased and damaged joints. With time, some joint replacements may require revision, mainly because of instability and mechanical loosening, and this is of particularly significance to younger patients. A major problem in revision surgery is the loss of bone stock and the consequent difficulty in reconstructing a stable joint. Loss of bone stock has been widely treated using bone autografts and allografts but supplies are limited. Use of bone graft substitutes in combination with, or as a substitute for, human bone is a possible alternative.

AIM

To identify empirical studies of bone graft substitutes in hip revision surgery.

METHODS

Systematic review based on Cochrane and MOOSE methods. We searched MEDLINE and EMBASE to December 2010 with terms relating to hip replacement and bone graft substitutes, and checked key citations in ISI Web of Science and reference lists. We considered all human studies irrespective of study design.

RESULTS

Searches identified 397 articles. Screening of abstracts and full text articles identified 7 studies reporting outcomes of bone-graft substitute combined with autograft or allograft, and 6 studies reporting outcomes of bone graft substitute exclusively. One economic evaluation compared costs of femoral head banking with costs of bone graft substitutes. No randomised controlled trials evaluating bone graft substitute effectiveness were identified. Studies generally included small numbers of patients with a follow up too short to assess outcomes relating to implant survival. However, excepting those based on glass ceramic, ceramic bone graft substitutes show promise as an alternative to use of exclusive autograft or allograft. In the case of calcium phosphate ceramic bone graft substitute, potential cost savings were evident.

CONCLUSION

With increased allograft shortage, bone graft substitutes will be required in hip revision surgery. However, appropriately designed randomised controlled trials are required to compare use of existing and new bone graft substitutes with established practice. As well as prosthesis related outcomes, studies should explore the patient experience of revision hip replacement with bone graft substitute material.

[Painful hip arthroplasty: a diagnostic algorithm]

The number of implantations of hip prostheses in Germany is now approximately 190,000 per year. By improving the implants and the development of modern surgical techniques and instruments the revision rate has been significantly reduced. The survival rate of the implants could be further increased in recent years, however, up to 22% of patients complain about persistent pain after hip arthroplasty. The diagnosis of existing pain after total joint replacement of the hip joint to achieve a causal therapy needs a systematic approach because of the heterogeneity of the symptoms and diseases. The etiology of the pain can be joint-associated and also hip joint independent. Often the causes of pain are multifactorial so that a standardized assessment should be conducted using an algorithm. The clarification of pain begins with the history, inspection and palpation followed by a clinical examination. It is then useful to perform radiological imaging followed by invasive procedures if necessary. The exploratory revision is nowadays considered to be obsolete in the literature.

THA after acetabular fracture fixation: is frozen section necessary?

BACKGROUND

Infection is uncommon after THA performed for failed acetabular fracture repair, despite a high reported incidence of culture-positive fixation implants. The use of frozen section analysis at the time of THA after acetabular fracture fixation surgery is unknown.

QUESTIONS/PURPOSES

We asked whether frozen section analysis predicted occult infection after THA performed after acetabular fracture repair.

METHODS

We retrospectively reviewed the charts of 43 of 49 patients with prior acetabular fracture fixation who had intraoperative frozen section and culture data from a conversion THA between 2002 and 2010. The average age of patients at fracture was 53 years; conversion was performed after an average of 553 days (median, 369 days; range, 51-2951 days). Five patients had an infection after acetabular fracture surgery (three deep, two superficial). At conversion we obtained an average of three frozen section specimens per patient; 10 specimens in eight patients contained greater than 10 polymorphonuclear cells/high-power field. The minimum followup was 51 days (median, 256 days; range, 51-2085 days).

RESULTS

Five patients had positive intraoperative cultures, three of whom had a positive frozen section. All patients who had prior deep infection developed positive intraoperative cultures. The sensitivity, specificity, positive predictive value, and negative predictive value of frozen section analysis were 0.60, 0.87, 0.38, and 0.94, respectively.

CONCLUSION

Infection complicating THA after acetabular fracture repair is uncommon. A history of deep infection complicating the acetabular fracture surgery was the strongest predictor of infection. Frozen section analysis has a high specificity and negative predictive value.

LEVEL OF EVIDENCE

Level III, diagnostic 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.

Risk of subsequent revision after primary and revision total joint arthroplasty

BACKGROUND

Revision is technically more demanding than primary total joint arthroplasty (TJA) and requires more extensive use of resources. Understanding the relative risk of rerevision and risk factors can help identify patients at high risk who may require closer postsurgical care.

OBJECTIVES/PURPOSES

We therefore evaluated the risk of subsequent revision after primary and revision TJA in the elderly (65 years or older) patient population and identified corresponding patient risk factors.

PATIENTS AND METHODS

Using the 5% Medicare claims data set (1997-2006), we identified a total of 35,746 patients undergoing primary THA and 72,913 undergoing primary TKA; of these, 1205 who had THAs and 1599 who had TKAs underwent initial revision surgery. The rerevision rate after primary and revision TJAs was analyzed by the Kaplan-Meier method. The relative risk of revision surgery for primary and revision TJAs was compared using hazard ratio analysis.

RESULTS

The 5-year survival probabilities were 95.9%, 97.2%, 81.0%, and 87.4% for primary THA and TKA and revision THA and TKA, respectively. Patients with revision arthroplasty were five to six times more likely to undergo rerevision (adjusted relative risk, 4.89 for THA; 5.71 for TKA) compared with patients with primary arthroplasty. Age and comorbidities were associated with initial revision after primary THA and TKA.

CONCLUSIONS

Patients should undergo stringent preoperative screening for preexisting health conditions and careful patient management and followup postoperatively so as to minimize the risk of an initial revision, which otherwise could lead to a significantly greater likelihood of subsequent rerevisions.

Factors influencing inpatient rehabilitation length of stay following revision hip replacements: a retrospective study

BACKGROUND

The annual incidence of revision hip replacements has increased in both Canada and United States, particularly in younger adults. Patients following revision hip replacements often require longer hospital length of stay (LOS) but little is known about predictors of inpatient rehabilitation LOS in this group of patients. The purpose of this study was to evaluate the socio-demographic, pre-surgery, surgery and post-surgery related factors that might influence rehabilitation LOS of inpatients following revision hip replacements.

METHODS

This study included inpatients discharged from a musculoskeletal ward between 2002 and 2006 following rehabilitation revision hip replacement. Data sources included the National Reporting System, a standardized, provincial administrative database and augmented by chart abstraction. The collected elements included the outcome LOS and the following independent variables: age, sex, support at home, environmental barriers, language barrier, number of revision surgeries on the affected hip, comorbidity, previous orthopaedic surgeries in the lower extremities (L/ES), the hip component(s) revised, weight-bearing status, hemoglobin level, complications, days lapsed from surgery to rehabilitation admission and admission scores on the Functional Independence Measure (FIM). Simple linear regression was used to take forward any predictors significant at p < .10 level. Variables that satisfied the significance level were grouped in blocks and entered for regression analyses.

RESULTS

The 275 patients in this sample had a mean age of 69 years; 62% were female and the mean LOS was 29.6 days. Statistically significant predictors of longer LOS were low admission FIM score, female sex, revision of only the femoral component, 2 or more prior surgeries in the L/Es and 2 or more hip revisions (redo revision). The final model explained 28% of variance in inpatient LOS.

CONCLUSIONS

A score of 9-14 points lower in admission FIM, female sex, revision of only the femoral component, prior surgeries in the L/Es and redo hip revision are all independent factors associated with 4-6 days longer LOS. These results may facilitate an understanding of bed flow. Additionally, patients with one or a combination of the above characteristics may benefit from enhanced care plans that facilitate achievement of rehabilitation goals for discharge home.

Uncemented computer-assisted design-computer-assisted manufacture femoral components in revision total hip replacement

We prospectively evaluated the long-term outcome of 158 consecutive patients who underwent revision total hip replacement using uncemented computer-assisted design-computer-assisted manufacture femoral components. There were 97 men and 61 women. Their mean age was 63.1 years (34.6 to 85.9). The mean follow-up was 10.8 years (10 to 12).

The mean Oxford, Harris and Western Ontario and McMaster hip scores improved from 41.1, 44.2 and 52.4 pre-operatively to 18.2, 89.3 and 12.3, respectively (p < 0.0001, for each). Six patients required further surgery. The overall survival of the femoral component was 97% (95% confidence interval 94.5 to 99.7). These results are comparable to those of previously published reports for revision total hip replacement using either cemented or uncemented components.

Revision hip arthroplasty: infection is the most common cause of failure

BACKGROUND

Revision total hip arthroplasty (THA), although relieving pain and restoring function, fails in some patients. In contrast to failures in primary THA, the frequency of the causes of failure in revision THA has been less well established.

QUESTIONS/PURPOSES

We therefore determined the rate of each failure mode and the survivorship of revision THAs.

METHODS

We retrospectively reviewed the charts of 1366 revision THAs performed between 2000 and 2007. There were 609 (44.5%) men and 757 (55.5%) women with a mean age of 66 years. The indications for the revision surgery were mainly aseptic loosening (51%), instability (15%), wear (14%), and infection (8%). The minimum followup was 1 day (mean, 5.5 years; range, 1 day to 9 years).

RESULTS

Two hundred fifty-six of the revisions (18.7%) failed with an average time to failure of 16.6 months (range, 1 day to 7.5 years). Among 256 failed hips, infection was the most common cause of failure (30.2%) followed by instability (25.1%) and aseptic loosening (19.4%). At 5 years, the survivorships of septic and aseptic groups were 67% and 84.8%, respectively. Revision for infection or instability appears to have a considerably lower survivorship when compared to revision for aseptic causes.

CONCLUSIONS

The lower survivorship of revision for infection or instability highlights the importance of implementing better preventative methods that can minimize the impact of these two major causes of failure.

LEVEL OF EVIDENCE

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