Revision For Loosening Research Articles

2024 Roger A. Mann Award Winner: Periprosthetic Tibial Lucency Following Low-Profile Total Ankle Arthroplasty

Category: Ankle Arthritis; Ankle Introduction/Purpose: Fourth generation total ankle arthroplasty (TAA) implants minimize tibial resection and utilize small pegs or posts for fixation. The components are designed to facilitate osseous integration. However, a number of studies have identified concerning rates of lucencies around the tibial components of all newer generation implants. In this study, we evaluated a consecutive series of patients receiving a fourth generation TAA prosthesis to describe the incidence and characteristics of tibial component lucencies at minimum one year follow-up. Of these patients, we aimed to identify the rate of revision surgery. Secondary aims included identifying any difference in patient factors between patients with global lucencies and a cohort of patients without lucencies. Methods: A prospectively-collected TAA registry was queried to identify eligible patients. All patients greater than 18 years old who underwent primary TAA with a Cadence, Infinity, Infinity Adaptis, or Vantage prosthesis through January 2021 were identified. Each surgery was performed by one of six fellowship-trained orthopedic foot and ankle surgeons. For radiographic analyses, lucency was defined as a radiolucent line adjacent to the tibial tray of at least 1 mm in thickness, comprising at least 50% of the zone (Figure). Poorly-defined lucency around the tibial component in all four tibial zones, as agreed upon by two independent reviewers, was considered “global lucency.” Intraoperative, one year, and two year postoperative radiographs were assessed for periprosthetic lucencies. Pre- and postoperative coronal tibiotalar alignment was recorded. Additional data collected included age, sex, BMI, diagnosis, presence of diabetes, smoking status, presence of ipsilateral hindfoot fusion, pre- and postoperative PROMIS scores, and reoperation and complication data. Results: 616 ankles were analyzed: 274 Vantage (44.4%), 253 Infinity (41.1%), 52 Cadence (8.4%), and 37 Infinity Adaptis (6.0%). Mean radiographic follow-up was 27±20 months. There were 28 revisions (4.5%), 21 (3.4%) for symptomatic tibial component loosening. 36 patients (5.8%) had global tibial lucency at one year. Of these, 15 (42%) were eventually revised and the remaining 21 (58%) were doing well clinically at final follow-up. When comparing patients with global lucency at 1 year and revision for loosening (42 patients, 6.8%) with the remaining patients, there were no significant differences in any of the factors assessed (Table). PROMIS pain interference scores were higher at 2 years in the loosening group (p = 0.03). Intraoperative lucencies were not predictive of global lucency or revision for loosening. Conclusion: Aseptic loosening is the most common mode of failure of TAA, and has been reported with all of the low-profile fourth generation implants. We found a 6.8% incidence of tibial loosening (global radiographic lucency at 1 year or revision for tibial loosening). We were unable to identify any patient factors associated with loosening. Although 50% of these patients did not require revision and were doing well clinically at early follow-up, tibial loosening was associated with higher PROMIS pain interference scores at 2 years. Further research will be required to determine how patients with tibial loosening fare over longer-term follow-up.

What Is the Outcome of the First Revision Procedure of Primary THA for Osteoarthritis? A Study From the Australian Orthopaedic Association National Joint Replacement Registry.

Joint arthroplasty registries traditionally report survivorship outcomes mainly on primary joint arthroplasty. The outcome of first revision procedures is less commonly reported, because large numbers of primary procedures are required to analyze a sufficient number of first revision procedures. Additionally, adequate linkage of primary procedures to revisions and mortality is required. When undertaking revision hip surgery, it is important for surgeons to understand the outcomes of these procedures to better inform patients. Using data from a large national joint registry, we asked: (1) What is the overall rate of revision of the first aseptic revision procedure for a primary THA? (2) Does the rate of revision of the first revision vary by the diagnosis for the first revision? (3) What is the mortality after the first revision, and does it vary by the reason for first revision? The Australian Orthopaedic Association National Joint Replacement Registry longitudinally maintains data on all primary and revision joint arthroplasties, with nearly 100% capture. The analyses for this study were performed on primary THA procedures in patients with a diagnosis of osteoarthritis up to December 31, 2020, who had undergone subsequent revision. We excluded all primary THAs involving metal-on-metal and ceramic-on-metal bearing surfaces and prostheses with exchangeable necks because these designs may have particular issues associated with revisions, such as extensive soft tissue destruction, that are not seen with conventional bearings, making a comparative analysis of the first revision involving these bearing surfaces more complicated. Metal-on-metal bearing surfaces have not been used in Australia since 2017. We identified 17,046 first revision procedures from the above study population and after exclusions, included 13,713 first revision procedures in the analyses. The mean age at the first revision was 71 ± 11 years, and 55% (7496 of 13,713) of the patients were women. The median (IQR) time from the primary procedure to the first revision was 3 years (0.3 to 7.3), ranging from 0.8 years for the diagnosis of dislocation and instability to 10 years for osteolysis. There was some variation depending on the reason for the first revision. For example, patients undergoing revision for fracture were slightly older (mean age 76 ± 11 years) and patients undergoing revision for dislocation were more likely to be women (61% [2213 of 3620]). The registry has endeavored to standardize the sequence of revisions and uses a numerical approach to describe revision procedures. The first revision is the revision of a primary procedure, the second revision is the revision of the first revision, and so on. We therefore described the outcome of the first revision as the cumulative percent second revision. The outcome measure was the cumulative percent revision, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the second revision. Hazard ratios from Cox proportional hazards models, adjusting for age and gender, were performed to compare the revision rates among groups. When possible, the cumulative percent second revision at the longest follow-up timepoint was determined with the available data, and when there were insufficient numbers, we used appropriate earlier time periods. The cumulative percent second revision at 18 years was 26% (95% confidence interval [CI] 24% to 28%). When comparing the outcome of the first revision by reason, prosthesis dislocation or instability had the highest rate of second revision compared with the other reasons for first revision. Dual-mobility prostheses had a lower rate of second revision for dislocation or instability than head sizes 32 mm or smaller and when compared to constrained prostheses after 3 months. There was no difference between dual-mobility prostheses and head sizes larger than 32 mm. There were no differences in the rate of second revision when first revisions for loosening, periprosthetic fracture, and osteolysis were compared. If cemented femoral fixation was performed at the time of the first revision, there was a higher cumulative percent second revision for loosening than cementless fixation from 6 months to 6 years, and after this time, there was no difference. The overall mortality after a first revision of primary conventional THA was 1% at 30 days, 2% at 90 days, 5% at 1 year, and 40% at 10 years. A first revision for periprosthetic fracture had the highest mortality at all timepoints compared with other reasons for the first revision. Larger head sizes and dual-mobility cups may help reduce further revisions for dislocation, and the use of cementless stems for a first revision for loosening seems advantageous. Surgeons may counsel patients about the higher risk of death after first revision procedures, particularly if the first revision is performed for periprosthetic fracture.Level of Evidence Level III, therapeutic study.

A Prospective, Longitudinal Study of the Influence of Obesity on Total Knee Arthroplasty Revision Rate: Results from the Australian Orthopaedic Association National Joint Replacement Registry.

The aim of this study was to investigate the relationship of obesity with all-cause revision and revision for infection, loosening, instability, and pain after total knee arthroplasty (TKA) performed in Australia. Data for patients undergoing primary TKA for osteoarthritis from January 1, 2015, to December 31, 2020, were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The rates of all-cause revision and revision for infection, loosening, instability, and pain were compared for non-obese patients (body mass index [BMI], 18.50 to 29.99 kg/m 2 ), class-I and II obese patients (BMI, 30.00 to 39.99 kg/m 2 ), and class-III obese patients (BMI, ≥40.00 kg/m 2 ). The results were adjusted for age, sex, tibial fixation, prosthesis stability, patellar component usage, and computer navigation usage. During the study period, 141,673 patients underwent primary TKA for osteoarthritis in Australia; of these patients, 48.0% were class-I or II obese, and 10.6% were class-III obese. The mean age was 68.2 years, and 54.7% of patients were female. The mean follow-up period was 2.8 years. Of the 2,655 revision procedures identified, the reasons for the procedures included infection in 39.7%, loosening in 14.8%, instability in 12.0%, and pain in 6.1%. Class-I and II obese patients had a higher risk of all-cause revision (hazard ratio [HR], 1.12 [95% confidence interval (CI), 1.03 to 1.22]; p = 0.007) and revision for infection (HR, 1.25 [95% CI, 1.10 to 1.43]; p = 0.001) than non-obese patients. Class-III obese patients had a higher risk of all-cause revision after 1 year (HR, 1.30 [95% CI, 1.14 to 1.52]; p < 0.001), revision for infection after 3 months (HR, 1.72 [95% CI, 1.33 to 2.17]; p < 0.001), and revision for loosening (HR, 1.39 [95% CI, 1.00 to 1.89]; p = 0.047) than non-obese patients. The risks of revision for instability and pain were similar among groups. Obese patients with knee osteoarthritis should be counseled with regard to the increased risks associated with TKA, so they can make informed decisions about their health care. Health services and policymakers need to address the issue of obesity at a population level. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Factors Affecting the Risk of Aseptic Patellar Complications in Primary TKA Performed with Cemented All-Polyethylene Patellar Resurfacing.

Patellar complications are a consequential cause of failure of primary total knee arthroplasty (TKA). The purpose of this study was to evaluate the association of demographic and patient factors with the long-term risk of patellar complications as a function of time in a very large cohort of primary TKAs performed with patellar resurfacing. We identified 27,192 primary TKAs utilizing cemented all-polyethylene patellar components that were performed at a single institution from 1977 through 2015. We evaluated the risk of any aseptic patellar complication and any aseptic patellar reoperation or revision, subanalyzed risks of reoperation or revision for loosening, maltracking/instability, and wear, and evaluated the risk of clinical diagnosis of patellar fracture and clunk/crepitus. The mean age at TKA was 68 years (range, 18 to 99 years); 57% of the patients were female. The mean body mass index (BMI) was 32 kg/m2. The primary diagnosis was osteoarthritis in 83%, and 70% of the TKAs were posterior-stabilized. Median follow-up was 7 years (range, 2 to 40 years). Risk factors for each outcome were evaluated with Cox regression models. Nine hundred and seventy-seven knees with all-polyethylene patellae developed patellar complications. Survivorship free from any aseptic patellar complication was 93.3% at 20 years. Twenty-year survivorship free from any aseptic patellar reoperation was 97.3% and free from any aseptic patellar revision was 97.4%. Fifteen-year survivorship for the same end points for procedures performed from 2000 to 2015 was 95.7%, 99.2% and 99.3% respectively, representing substantial improvements compared with implants placed before 2000. Univariate analysis demonstrated that male sex (hazard ratio [HR], 1.4), an age of <65 years (HR, 1.3), and a BMI of ≥30 kg/m2 (HR, 1.2) were associated with increased risk of patellar complications (all p ≤0.01). Posterior-stabilized designs were associated with fewer patellar reoperations and revisions overall (HR, 0.4 and 0.4; p < 0.001) but higher risk of patellar clunk/crepitus (HR, 14.1; p < 0.001). The 20-year survivorship free from any aseptic patellar complication in this series of cemented all-polyethylene patellae was 93%. Important risk factors for any aseptic patellar complication were male sex, an age of <65 years, a BMI of ≥30 kg/m2, and a patella implanted before 2000. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Highly cross-linked polyethylene (HXLPE) is equivalent to conventional polyethylene (CPE) in total knee arthroplasty: A systematic review and meta-analysis

BackgroundThe benefits of HXLPE in total knee arthroplasty (TKA) have not been as evident as total hip arthroplasty (THA). A systematic review and meta-analysis to assess the impact of highly-crosslinked polyethylene (HXLPE) on TKA outcomes compared to conventional polyethylene (CPE) is described. MethodsAll studies comparing HXLPE with CPE for primary TKA were included for analysis. The minimum dataset included revision rates, indication for revision, aseptic component loosening and follow-up time. The primary outcome variables were all-cause revision, aseptic revision, revision for loosening, radiographic component loosening, osteolysis and incidence of radiolucent lines. Secondary outcome measures included postoperative functional knee scores. A random-effects meta-analysis allowing for all missing data was performed for all primary outcome variables. ResultsSix studies met the inclusion criteria. In total, there were 2,234 knees (1,105 HXLPE and 1,129 CPE). The combined mean follow-up for all studies was 6 years. The aseptic revision rate in the HXLPE group was 1.02% compared to 1.97% in the CPE group. There was no difference in the rate of all-cause revision (p = 0.131), aseptic revision (p = 0.298) or revision for component loosening (p = 0.206) between the two groups. Radiographic loosening (p = 0.200), radiolucent lines (p = 0.123) and osteolysis (p = 0.604) was similar between both groups. Functional outcomes were similar between groups. ConclusionThe use of HXLPE in TKA yields similar results for clinical and radiographic outcomes when compared to CPE at midterm follow-up. HXLPE does not confer the same advantages to TKA as seen in THA.

The effect of cemented acetabular component geometry on the risk of revision for instability or loosening : a study of 224,874 primary hip arthroplasties from the National Joint Registry.

To determine if primary cemented acetabular component geometry (long posterior wall (LPW), hooded, or offset reorientating) influences the risk of revision total hip arthroplasty (THA) for instability or loosening. The National Joint Registry (NJR) dataset was analyzed for primary THAs performed between 2003 and 2017. A cohort of 224,874 cemented acetabular components were included. The effect of acetabular component geometry on the risk of revision for instability or for loosening was investigated using log-binomial regression adjusting for age, sex, American Society of Anesthesiologists grade, indication, side, institution type, operating surgeon grade, surgical approach, polyethylene crosslinking, and prosthetic head size. A competing risk survival analysis was performed with the competing risks being revision for other indications or death. The distribution of acetabular component geometries was: LPW 81.2%; hooded 18.7%; and offset reorientating 0.1%. There were 3,313 (1.5%) revision THAs performed, of which 815 (0.4%) were for instability and 838 (0.4%) were for loosening. Compared to the LPW group, the adjusted subhazard ratio of revision for instability in the hooded group was 2.31 (p < 0.001) and 4.12 (p = 0.047) in the offset reorientating group. Likewise, the subhazard ratio of revision for loosening was 2.65 (p < 0.001) in the hooded group and 13.61 (p < 0.001) in the offset reorientating group. A time-varying subhazard ratio of revision for instability (hooded vs LPW) was found, being greatest within the first three months. This registry-based study confirms a significantly higher risk of revision after cemented THA for instability and for loosening when a hooded or offset reorientating acetabular component is used, compared to a LPW component. Further research is required to clarify if certain patients benefit from the use of hooded or offset reorientating components, but we recommend caution when using such components in routine clinical practice. Cite this article: Bone Joint J2021;103-B(11):1669-1677.

Cause for revision differs between a short and standard length stem at 5 year follow-up

BackgroundThe purpose of this study was to compare the 5 year radiographic and clinical outcomes of anatomic total shoulder arthroplasties (TSA) performed with either a standard length (SL) or short stem. The hypothesis was there would be no difference in radiographic or clinical outcomes based on stem length. MethodsA multicenter retrospective review was performed of primary TSAs performed with a press-fit humeral component. Fifty SL and 72 short stems were available for review, of which 43 SL and 60 short stems had minimum 5 year follow-up. Functional outcome was assessed according to range of motion (ROM), visual analog scale (VAS) American Shoulder and Elbow Surgeons (ASES), and Single Assessment Numeric Evaluation (SANE) scores. Radiographs were reviewed for signs of humeral component loosening and stress shielding. ResultsAt final follow-up there were no differences in ROM, or ASES or SANE scores between groups (P>.05). Postoperative VAS scores were lower in the SL compared to the short stems (0.8 vs. 1.6; P = .053). All-cause revision was similar between the SL and short stems (16% vs. 22.2%; P = .395). Among SL stems there were no revisions for humeral loosening and none were considered radiographically at risk. Six short stems were revised for loosening (8.3%; P =.036 vs. SL). An additional 5 short stems were considered to be radiographically at risk for loosening for a total revision or at risk rate of 15.3% (P = .003 vs. SL). ConclusionThere is no difference in functional outcome at mid-term follow-up of TSA based on stem length with a grit-blasted humeral component. Revision for loosening and radiographic risk for loosening may be higher with a short stem compared a standard length humeral stem placed with press-fit fixation using grit blasting. Level of evidenceLevel III; Retrospective Comparative Study.

Ceramic-on-ceramic articulation in press-fit total hip arthroplasty as a potential reason for early failure, what about the survivors: a ten\xa0year follow-up

PurposeIn press-fit total hip arthroplasty (THA), primary stability is needed to avoid micromotion and hereby aseptic loosening, the main reason for early revision. High aseptic loosening revision rates of the seleXys TH+ cup (Mathys Medical) with Ceramys ceramic-on-ceramic (CoC) bearing are seen in literature. Since CoC is presumed to overcome long-term wear-related revisions, the reason for early failure of this cup is important to clarify. The aim is to investigate its ten year outcomes and differentiate between potential causes and identify risk factors for aseptic loosening.MethodsRetrospective screening of a prospectively documented series of 315 THAs was performed. Primary outcome was cumulative incidence of cup revision due to aseptic loosening. Secondary outcomes were component revision and reoperation. Additionally, potential predictive factors for aseptic loosening were evaluated.ResultsAt the median follow-up of 9.7 years [IQR 4.4; 10.3], 48 TH+ (15.2%) were revised due to aseptic loosening. Competing risk analysis showed a ten year cumulative incidence of cup revision due to aseptic loosening of 15.6% (95% CI 12.0–20.2). Stabilization of early revision rates was observed, following a high rate of respectively 81.3% (n = 39) and 95.8% (n = 46) within the first two and three years. No significant predictive factors for aseptic loosening were found.ConclusionThe ten year results of seleXys TH+ cup with Ceramys CoC bearing showed an unacceptable high aseptic loosening rate, which stabilized over time after a high early failure incidence. This could be attributed to a problem with osseointegration during the transition of primary to definitive stability.

Ten-year clinical and radiographic results of 1000 cementless Oxford unicompartmental knee replacements

PurposeUnicompartmental knee replacement (UKR) has substantial benefits over total knee replacement (TKR) but has higher revision rates. The cementless Oxford UKR was introduced to address this but there are concerns about fixation and tibial plateau fractures. The first long-term study of the device with clinical and radiographic outcomes is reported.MethodsThe first 1000 medial cementless Oxford UKR were prospectively identified and followed up by independent physiotherapists. Survival was calculated using the endpoints reoperation, revision, revision to TKR, major revision requiring revision TKR components and patient mortality. The Oxford Knee Score (OKS), Tegner Activity Score and American Knee Society Score (AKSS) were recorded and radiographs analysed.ResultsThe ten year survival was 96.6% (CI 94.8–97.8), 97.5% (CI 95.7–98.5), 98.9% (CI 97.7–99.4) and 99.6% (CI 98.8–99.9) using reoperation, revision, revision to TKR and major revision as the endpoint, respectively. Commonest causes for revision were bearing dislocation (n = 7, 0.7%), disease progression (n = 4, 0.4%) and pain (n = 2, 0.2%). There was one lateral tibial plateau fracture and one femoral component loosening. At 10 years, the mean OKS was 41.2 (SD 9.8), Tegner 2.8 (SD 1.3), AKSS-O 89.1 (SD 13.0) and AKSS-F 80.4 (SD 14.6). There were no pathological radiolucencies or complete radiolucent lines. There were no implant-related deaths.ConclusionsThe cementless Oxford UKR is a safe procedure with excellent long-term clinical results. Our results suggest that reliable fixation was achieved with only one (0.1%) revision for loosening (femoral), no radiographic evidence of loosening in the remaining cases and no fractures related to implantation.Level of evidenceIII.

How to reduce osteopenia in total knee arthroplasty?

Osteopenia of the front half of the distal femur is a well-known problem after total knee arthroplasty (TKA) with secondary issues after years, especially when must be addressed fractures or revisions for loosening. Stress shielding has been recognized as a cause in different biomechanical studies of the bone. It was logical to look for a solution by changing the design to minimize stress shielding behind the femoral shield. It was proved that radiological measure of bone density was reliable although not so early and accurate as densitometry. We used a shield without posterior fixation of the trochlea in a series of 21 TKA with radiological measures, preoperative, at 3months and at 5years. We compared the results with those of a series of classical TKA in the same category of age and sex. The TKA without trochlea posterior fixation presented a significantly reduced osteopenia compared to the classical design of the femoral shield. It seems that the non-fixation of the posterior surface of the trochlea may reduce osteopenia in TKA and so the risk of fractures and complications when revision surgery. 2a.

Large Metal Heads and Highly Cross-Linked Polyethylene Provide Low Wear and Complications at 5-13 Years

BackgroundHighly cross-linked polyethylene (XLPE) is reported to have low rates of linear and volumetric wear at 10-14 years. In a prior study, larger (36 and 40 mm) femoral heads were associated with more volumetric wear, but there were only 12 hips with these heads. MethodsWe evaluated 107 hips (93 patients, with a mean age of 76 years) with one design of uncemented acetabular component, a 36 (90 hips) or 40 mm (17 hips) metal femoral head, and one electron beam 100 kGy irradiated and remelted XLPE at a mean follow-up of 8 years (range 5-13 years). Selection of these femoral heads was based on several factors, including the perceived risk of dislocation, the outer diameter size of the acetabular component, and liner availability. Measurements of linear and volumetric wear were performed in one experienced laboratory by the Martell method and analyzed using the first-to-last method. Standard radiographs, with additional Judet views, were used to detect periprosthetic osteolysis. Clinical records were used to determine the complications of dislocation, liner fracture, and painful trunnion corrosion. ResultsFor the entire cohort, the median linear wear rate was 0.041 mm/y (95% confidence interval, 0.031-0.057) and the median volumetric wear rate was 34.6 mm3/y (95% confidence interval, 31.4-53.5). With the numbers available, there was no difference in linear or volumetric wear between the 36 and 40 mm head sizes. Small, asymptomatic osteolytic lesions were noted in 3 hips (2%). There were 3 patients (3%) with dislocation (2 early and 1 late), but these have not had a revision. There were no revisions for loosening, no liner fracture, and no patient with symptomatic trunnion corrosion. ConclusionThis acetabular component and XLPE with large metal heads had low rates of linear and volumetric wear. Large metal femoral heads did not lead to liner fracture, loosening, or symptomatic trunnion corrosion in this patient population. However, we recommend longer clinical follow-up studies and caution in the routine use of larger metal femoral heads in other, younger patient populations.

Total Knee Replacement with an Oxidised Zirconium Femoral Component

Objectives:Oxidized zirconium was introduced as a material for femoral components in total knee replacement (TKR) to reduce polyethylene wear. However the long term survival of this prosthesis is not known.Methods:A series of 303 consecutive oxidised zirconium TKR were performed over a 3 year period and prospectively included in a database. Subjects were assessed preoperatively and 10 years after TKR. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score (KOOS), radiographic evaluation and a patient satisfaction.Results:A total of 303 consecutive TKRs were performed in 278 patients with a mean age of 68 years (range 45 to 89 years). The ten year survival rate from the Kaplan–Meier predicted survivorship was 97% (95% CI 94 - 99) with revision for any reason as the endpoint. There were no revisions for loosening, osteolysis or implant failure. There was a significant improvement in all components of the WOMAC score at final follow up (p<0.001). The mean individual components of the KOOS score for symptoms (82.4 points), pain (87.5 points), activities of daily life (84.9 points) and quality of life (71.4 points) were all at higher end of the scale.Conclusion:The oxidized zirconium TKR is associated with favourable survival rates and excellent functional outcomes at ten years.

Total knee arthroplasty with an oxidised zirconium femoral component: ten-year survivorship analysis.

Oxidised zirconium was introduced as a material for femoral components in total knee arthroplasty (TKA) as an attempt to reduce polyethylene wear. However, the long-term survival of this component is not known. We performed a retrospective review of a prospectively collected database to assess the ten year survival and clinical and radiological outcomes of an oxidised zirconium total knee arthroplasty with the Genesis II prosthesis. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and a patient satisfaction scale were used to assess outcome. A total of 303 consecutive TKAs were performed in 278 patients with a mean age of 68 years (45 to 89). The rate of survival ten years post-operatively as assessed using Kaplan-Meier analysis was 97% (95% confidence interval 94 to 99) with revision for any reason as the endpoint. There were no revisions for loosening, osteolysis or failure of the implant. There was a significant improvement in all components of the WOMAC score at final follow-up (p < 0.001). The mean individual components of the KOOS score for symptoms (82.4 points; 36 to 100), pain (87.5 points; 6 to 100), activities of daily life (84.9 points; 15 to 100) and quality of life (71.4 points; 6 to 100) were all at higher end of the scale. This study provides further supportive evidence that the oxidised zirconium TKA gives comparable rates of survival with other implants and excellent functional outcomes ten years post-operatively. Total knee arthroplasty with an oxidised zirconium femoral component gives comparable long-term rates of survival and functional outcomes with conventional implants.

A minimum 5-year follow-up of an oxidized zirconium femoral prosthesis used for total knee arthroplasty

BackgroundBearing surface wear remains a potential concern amongst younger patients undergoing total knee arthroplasty (TKA). Because of the potential for lower prosthetic wear rates, oxidized zirconium is a potentially attractive bearing surface for TKA in young, active patients. This material is also well suited for patients with suspected nickel sensitivities as it has no measurable nickel content, in contrast to standard femoral bearings made of cobalt-chromium alloys. Although in vitro testing on knee wear simulators has demonstrated favorable wear characteristics of oxidized zirconium compared to traditional cobalt-chrome bearings, in vivo clinical outcome data with this novel bearing surface are sparse. MethodsWe retrospectively reviewed 109 consecutive TKAs in 82 patients at a minimum of five years postoperatively to determine prosthetic survivorship and to assess whether any adverse clinical consequences could be attributed to this bearing. Knees were evaluated with Knee Society scores, UCLA activity scores, clinical examinations, and radiographs. The mean age for this cohort was 58.7years. ResultsSurvivorship free of bearing related complications was 100% at a minimum of five years post-surgery. There were no revisions for loosening, osteolysis, implant failure, or deep infection. There were no knees with radiographic failure, visible wear, loosening, or osteolysis. ConclusionOxidized zirconium remains an attractive option for patients with nickel sensitivities and in those patients at risk for prosthetic wear due to young age or high activity levels.

A prospective clinical and radiological study comparing hydroxyapatite-coated with cemented tibial components in total knee replacement

This prospective study compares the outcome of 157 hydroxyapatite (HA)-coated tibial components with 164 cemented components in the ROCC Rotating Platform total knee replacement in 291 patients. The mean follow-up was 7.6 years (5.2 to 11). There were two revisions for loosening: one for an HA-coated and one for a cemented tibial component. Radiological evaluation demonstrated no radiolucent lines with the HA-coated femoral components. A total of three HA-coated tibial components exhibited radiolucent lines at three months post-operatively and these disappeared after three further months of protected weight-bearing. With HA-coated components the operating time was shorter (p<0.006) and the radiological assessment of the tibial interface was more stable (p < 0.01). Using revision for aseptic loosening of the tibial component as the end point, the survival rates at nine years was identical for both groups at 99.1%. Our results suggest that HA-coated components perform at least as well as the same design with cemented components and compare favourably with those of series describing cemented or porous-coated knee replacements, suggesting that fixation of both components with hydroxyapatite is a reliable option in primary total knee replacement.

Results of a Second-Generation Constrained Condylar Prosthesis in Primary Total Knee Arthroplasty

This is a prospective study of the results of a second-generation modular constrained condylar knee (CCK) prosthesis in primary total knee arthroplasty. Of 418 consecutive total knee arthroplasties performed by 1 surgeon, a second-generation modular CCK prosthesis was indicated for intraoperative stability in 30 knees (7.2%). Three knees were lost to follow-up, and 27 knees had a mean follow-up time of 5.4 years (range, 2-11.5 years). All tibial components had a cemented 35-mm stem extension, and 26 femoral components had a 100-mm uncemented stem extension. The indication for use of the CCK components was most commonly severe valgus deformity and incompetent medial collateral ligament. There were no revisions for loosening, patella problems, or tibial post fracture. A lateral retinacular release of the patella was performed in 6 knees (22%). An asymptomatic, minimally displaced patella fracture was noted in 2 knees (7.4%). Constrained condylar knees are used infrequently now but are successful for the treatment of the unstable primary knee that cannot be balanced. These results may be design specific.

Modified Extended Trochanteric Osteotomy with Preservation of Posterior Structures

The purpose of the study was to describe the technique and the clinical results of the modified extended trochanteric osteotomy (ETO) with a lateral approach to the hip. This osteotomy differs from those previously described, as it preserves the posterior part of the greater trochanter and its attached external rotators, the aim of this modification being to minimize the rate of hip dislocation. We reviewed the results of 105 extended sliding trochanteric osteotomies performed between January 2000 to January 2008. The indication for surgery was aseptic loosening in 83 cases, periprosthetic fractures in 10 cases, stem fracture in 5 cases, infection in 5 cases and instability in 2 cases. Minimum follow up was 20 months (mean, 65; range, 20-120 months). Mean length of the osteotomy was 17.6 cm (range, 9-30 cm). Mean Harris hip score improved from 39 points preoperatively to 73 at last follow up. Six stems (6%) needed revision for loosening. There was one case (1%) of osteotomy nonunion, and one case (1%) of greater trochanteric fragment nonunion and escape. Four patients (4%) dislocated postoperatively.

Long-Term Follow-Up of a Hydroxyapatite Ceramic–Coated Threaded Cup: An Analysis of Survival and Fixation at up to 15 Years

We evaluated the survival of 112 consecutive JRI hydroxyapatite ceramic–coated threaded acetabular components (JRI Ltd, London, UK). Follow-up was for a minimum of 13 years (range, 13-15 years). Patients were assessed clinically and radiographically using the Merle d'Aubigné and Postel scoring systems and the De Lee and Charnley zones. Cup angle, migration, and signs of radiolucency were used to assess loosening. The criteria for failure were revision or impending revision due to pain and septic or aseptic loosening. The mean results of the Merle d'Aubigné and Postel score for pain, motion, and ability to walk were 2.2/2.7/2.2 preoperatively and 5.6/4.3/5.1 postoperatively. There was 100% endosteal bone formation in De Lee and Charnley zones 1 and 3 and 87% in zone 2. No reactive lines were seen in any zone in any cup. There were no cases of migration, change in cup angle, or revision for loosening. Our survival was 99% at 13 years (95% confidence interval, 96-100).

Radiographic Evaluation of a Monoblock Acetabular Component: A Multicenter Study With 2- to 5-Year Results

Serial radiographs of a porous tantalum monoblock acetabular cup design were evaluated for cup stability and signs of successful osteointegration. Of 574 primary consecutive total hip replacements in 542 patients performed by 9 surgeons at 7 hospitals, 414 cases were available for minimum 2-year follow-up. Follow-up averaged 33 months and ranged from 24 to 58 months. Postoperative radiographs revealed acetabular gaps in 100 zones in 80 (19%) hips: 29 in zone I, 67 in zone II, and 4 in zone III. At last follow-up, 84 (84%) of the zones with gaps completely filled in, and all 4- and 5-mm gaps filled in. There was no progression of any postoperative gap, no evidence of continuous periacetabular interface radiolucencies, no evidence of lysis, and no revisions for loosening. Although these short-term results are encouraging, further follow-up will be required to assess whether the monoblock design and the low modulus of elasticity of porous tantalum will reduce the incidence of periacetabular stress shielding and occurrence of osteolysis.

Clinical and radiographic outcome of Lord-type noncemented total hip arthroplasty in patients aged 70 years or older

We investigated the clinical and radiographic outcome of 35 Lord-type noncemented total hip arthroplasties (THAs) in 30 patients who were aged 70 years or older at surgery and were followed for a minimum of 5 (mean 7.0) years. The mean Harris hip score was 38.6±9.3 before surgery and 85.6±9.1 after 5 years of follow-up. Eighty-nine percent of the patients were satisfied with the functional outcome. Reoperation was done on two hips (6%) because of aseptic loosening—revision of both stem and cup in one, and revision of the stem in one. At the 5-year examination, stem subsidence occurred more frequently with the smooth-surfaced stem (Polarisee and LFR prostheses) than the bead-coated stem (Madreporic and Mark-II prostheses) (p<0.05). By setting the endpoint at the time when revision was performed, or cup migration or stem subsidence by 5 mm or more was radiographically confirmed, the 10-year survival rate of the threaded cup, bead-coated stem, and smooth-surfaced stem was 75.8%, 95.5%, and 70.5%, respectively. In conclusion, a long stem with full or extensive bead coating that is fixed without cement should be an effective option for THA in older patients.