Dislocation after total hip arthroplasty: implant design and orientation,”

Abstrac

High prevalence of radiographic outliers and revisions with unicompartmental knee arthroplasty

BACKGROUND: Alignment outcomes and their impact on implant survival following unicompartmental knee arthroplasty (UKA) are unclear. The purpose of this study was to assess the implant survival and radiographic outcomes after UKA as well as the impact of component alignment and overhang on implant survival. METHODS: We performed a retrospective analysis of 253 primary fixed-bearing and mobile-bearing medial UKAs from a single academic center. All UKAs were performed by 2 high-volume fellowship-trained arthroplasty surgeons. UKAs comprised \u3c10% of their knee arthroplasty practices, with an average of 14.2 medial UKAs per surgeon per year. Implant survival was assessed. Femoral coronal (FCA), femoral sagittal (FSA), tibial coronal (TCA), and tibial sagittal (TSA) angles as well as implant overhang were radiographically measured. Outliers were defined for FCA (\u3e±10° deviation from neutral), FSA (\u3e15° of flexion), TCA (\u3e±5° deviation from neutral), and TSA (\u3e±5° deviation from 7°). Far outliers were an additional \u3e±2° of deviation. Outliers for overhang were identified as \u3e3 mm for anterior overhang, \u3e2 mm for posterior overhang, and \u3e2 mm for medial overhang. RESULTS: Among patients with a failed UKA, revision was performed at an average of 3.7 years (range, 0.03 to 8.7 years). The cumulative revision rate was 14.2%. Kaplan-Meier survival analysis demonstrated 5 and 10-year survival rates of 88.0% (95% confidence interval [CI] = 82.0% to 91.0%) and 70.0% (95% CI = 56.0% to 80.0%), respectively. Only 19.0% (48) of the UKAs met target alignment for all 4 alignment measures, and only 72.7% (184) met all 3 targets for overhang. Only 11.9% (30) fell within all alignment and overhang targets. The risk of implant failure was significantly impacted by outliers for FCA (failure rate = 15.4%, p = 0.036), FSA (16.2%, p = 0.028), TCA (17.9%, p = 0.020), and TSA (15.2%, p = 0.034) compared with implants with no alignment or overhang errors (0%); this was also true for far outliers (p \u3c 0.05). Other risk factors for failure were posterior overhang (failure rate = 25.0%, p = 0.006) and medial overhang (38.2%, p \u3c 0.001); anterior overhang was not a significant risk factor (10.0%, p = 0.090). CONCLUSIONS: The proportions of UKA revisions and alignment outliers were greater than expected, even among high-volume arthroplasty surgeons performing an average of 14.2 UKAs per year (just below the high-volume UKA threshold of 15). Alignment and overhang outliers were significant risk factors for implant failure. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

An Evaluation of Economic Strategies in Budget Deficit Reduction in Kenya

Budget deficits have attracted a great deal of attention over the past few decades. This is so because financial experts have blamed it on all assortments of ills that beset developing countries. Some of these ills include: high inflation rates, over indebtedness, loss of a country’s sovereignty, crowding out of the private sector among others. In spite of its various attempt to widen the tax base and the numerous austerity measures to cut down on its recurrent expenditures, the Kenyan government like most of the other developing countries has over the years been a perpetual casualty of budget deficit. The purpose of this study was therefore to evaluate the economic strategies measures that the Kenyan government may put in place in order to reduce budget deficit. Specifically the research addressed how; tax policy, Inflation, technological innovation and government expenditure affects reduction of budget deficit in Kenya. The research will be of great significance to: the Kenyan Government, future scholars as well as the government of other countries with deficit budget. The research design adopted for the study was descriptive research design; the population was the 33 tax seniors in the 5 leading audit firms in the country namely PKF Kenya, Deloitte & Touché, KPMG, Ernst & Young Kenya and Price Water House & Coopers Kenya. Census method of sampling was adopted for selecting elements under study. Moreover both primary and secondary methods of data collection were used to collect data and the results thereon analyzed using Minitab version 17 and presented in form of: tables, charts, graphs and inferential statistics. The response rate from the questionnaires issued was 76% and most of the respondents asserted that the tax policy and the government expenditure were the main causes of the persistent budget deficits in Kenya and a number of recommendations were put forth on how best to address the same, among the recommended measures to deal with the tax policy included; widening the tax base to capture the juakali sector, revamping of the turnover tax system, more stringent measures to ensure compliance and a total overhaul of the VAT system which still has a very big growth potential. On the issue of government expenditure it was recommended that the numerous austerity measures that have over the years been proposed by the various Finance Bills be strictly adhered to so us to cut down on the avoidable public expenditures and equally the government to utilize concessional loans that have zero interest rates so as to cut down on interest repayments on its loans. Moreover the researcher found out that inflation was heavily contributing to the budget deficit in Kenya hence recommendable that the government initiates various fiscal and monetary policies to contain inflation to manageable levels. The researcher further recommended that investment in information technology be expedited as through it, KRA will be in a position to bring more persons in the tax net and consequently widen the tax base and equally fasten the tax collection process and facilitate various audit by the authority. Key Words: Economic strategies, Budget deficit in Keny

The impact of surgeon volume and training status on implant alignment in total knee arthroplasty

BACKGROUND: Implant malalignment may predispose patients to prosthetic failure following total knee arthroplasty (TKA). A more thorough understanding of the surgeon-specific factors that contribute to implant malalignment following TKA may uncover actionable strategies for improving implant survival. The purpose of this study was to determine the impact of surgeon volume and training status on malalignment. METHODS: In this retrospective multicenter study, we performed a radiographic analysis of 1,570 primary TKAs performed at 4 private academic and state-funded centers in the U.S. and U.K. Surgeons were categorized as high-volume (≥50 TKAs/year) or low-volume (\u3c50 TKAs/year), and as a trainee (fellow/resident under the supervision of an attending surgeon) or a non-trainee (attending surgeon). On the basis of these designations, 3 groups were defined: high-volume non-trainee, low-volume non-trainee, and trainee. The postoperative medial distal femoral angle (DFA), medial proximal tibial angle (PTA), and posterior tibial slope angle (PSA) were radiographically measured. Outlier measurements were defined as follows: DFA, outside of 5° ± 3° of valgus; PTA, \u3e±3° deviation from the neutral axis; and PSA, \u3c0° or \u3e7° of flexion for cruciate-retaining or \u3c0° or \u3e5° of flexion for posterior-stabilized TKAs. Far outliers were defined as measurements falling \u3e± 2° outside of these ranges. The proportions of outliers were compared between the groups using univariate and multivariate analyses. RESULTS: When comparing the high and low-volume non-trainee groups using univariate analysis, the proportions of knees with outlier measurements for the PTA (5.3% versus 17.4%) and PSA (17.4% versus 28.3%) and the proportion of total outliers (11.8% versus 20.7%) were significantly lower in the high-volume group (all p \u3c 0.001). The proportions of DFA (1.9% versus 6.5%), PTA (1.8% versus 5.7%), PSA (5.5% versus 12.6%), and total far outliers (3.1% versus 8.3%) were also significantly lower in the high-volume non-trainee group (all p \u3c 0.001). Compared with the trainee group, the high-volume non-trainee group had significantly lower proportions of DFA (12.6% versus 21.6%), PTA (5.3% versus 12.0%), PSA (17.4% versus 33.3%), and total outliers (11.8% versus 22.3%) (all p \u3c 0.001) as well as DFA (1.9% versus 3.9%; p = 0.027), PSA (5.5% versus 12.6%; p \u3c 0.001), and total far outliers (3.1% versus 6.4%; p = 0.004). No significant differences were identified when comparing the low-volume non-trainee group and the trainee group, with the exception of PTA outliers (17.4% versus 12.0%; p = 0.041) and PTA far outliers (5.7% versus 2.6%; p = 0.033). Findings from multivariate analysis accounting for the effects of patient age, body mass index, and individual surgeon demonstrated similar results. CONCLUSIONS: Low surgical volume and trainee status were risk factors for outlier and far-outlier malalignment in primary TKA, even when accounting for differences in individual surgeon and patient characteristics. Trainee surgeons performed similarly, and certainly not inferiorly, to low-volume non-trainee surgeons. Even among high-volume non-trainees, the best-performing cohort in our study, the proportion of TKA alignment outliers was still high. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence

Is retention of the acetabular component at revision surgery a long-term solution?

BACKGROUND: Acetabular retention in revision total hip arthroplasty (THA) may be advantageous, yet long-term survival data is limited. Thus, we investigated long-term survivorship of retained acetabular components in revision THA with analysis of rerevision rate, instability risk, and clinical outcomes. METHODS: We reviewed 98 hips with polyethylene wear and/or osteolysis that were revised with retained acetabular components. Acetabular inclination and anteversion were measured from prerevision radiographs. A retrospective chart review was performed, collecting outcomes of interest including Harris hip score, instability events, and rerevision surgery. Kaplan-Meier analysis was used to calculate the risk of revision over time. Predictors of survival including acetabular component position were analyzed by multiple logistic regression. RESULTS: Average follow-up was 13 years (range, 5-24). Survivorship rates at 5, 10, 15, and 20 years were 89.7%, 81.6%, 70.8%, and 63.8%, respectively. There was improvement in average Harris hip score (61 to 76, CONCLUSIONS: Retention of a well-fixed acetabular component in revision THA provides acceptable long-term outcomes with a 15-year survivorship of 71%. Instability and aseptic loosening were the most common reasons for rerevision. Surgeons may consider retaining the acetabular component at revision surgery if the implant is well-fixed and well-positioned