Validation of the Hip Disability and Osteoarthritis Outcome Score and Knee Injury and Osteoarthritis Outcome Score Pain and Function Subscales for Use in Total Hip Replacement and Total Knee Replacement Clinical Trials.

BACKGROUND: Total hip replacement (THR)/total knee replacement (TKR) studies do not uniformly measure patient centered domains, pain, and function. We aim to validate existing measures of pain and function within subscales of standard instruments to facilitate measurement. METHODS: We evaluated baseline and 2-year pain and function for THR and TKR using Hip disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS), with primary unilateral TKR (4796) and THR (4801). Construct validity was assessed by correlating HOOS/KOOS pain and activities of daily living (ADL), function quality of life (QOL), and satisfaction using Spearman correlation coefficients. Patient relevant thresholds for change in pain and function were anchored to improvement in QOL; minimally clinically important difference (MCID) corresponded to "a little improvement" and a really important difference (RID) to a "moderate improvement." Pain and ADL function scores were compared by quartiles using Kruskal-Wallis. RESULTS: Two-year HOOS/KOOS pain and ADL function correlated with health-related QOL (KOOS pain and Short Form 12 Physical Component Scale ρ = 0.54; function ρ = 0.63). Comparing QOL by pain and function quartiles, the highest levels of pain relief and function were associated with the most improved QOL. MCID for pain was estimated at ≥20, and the RID ≥29; MCID for function ≥14, and the RID ≥23. The measures were responsive to change with large effect sizes (≥1.8). CONCLUSION: We confirm that HOOS/KOOS pain and ADL function subscales are valid measures of critical patient centered domains after THR/TKR, and achievable thresholds anchored to improved QOL. Cost-free availability and brevity makes them feasible, to be used in a core measurement set in total joint replacement trials.

A greater reduction in the distal femoral anterior condyle improves flexion after total knee arthroplasty in patients with osteoarthritis.

BACKGROUND: The effect of an anterior condylar height (ACH) change after total knee arthroplasty (TKA) is not well-known. The effect of an ACH change was evaluated on postoperative knee flexion, New Knee Society Scores (2011KSS), and patellofemoral contact force. METHODS: The study included 101 knees that underwent TKA. The medial or lateral ACH was measured using pre-operative and postoperative computed tomography. Pearson correlation between the change in ACH and knee flexion was calculated. The determinant of the change in flexion was evaluated using multivariable linear regression. The association between ACH and 2011KSS was assessed. Using the cases with the three highest and three lowest pre-operative medial ACHs, computer simulation was performed to detect the changes in patellofemoral contact forces. RESULTS: A postoperative reduction in ACH correlated with increased flexion at one year (medial ACH, R = 0.58; lateral ACH, R = 0.48). On multivariable linear regression, reductions in medial ACH (ß = 1.7, P < 0.001) and pre-operative flexion (ß = -0.3, P < 0.001) were associated with increased flexion. A decrease in ACH was associated with improvements in advanced activities (medial, R2 = 0.06; lateral, R2 = 0.08) in 2011KSS. On computer simulation, all three cases with reduced and increased medial ACHs showed decreased and increased patellofemoral contact forces, respectively. CONCLUSIONS: A change in ACH was an independent predictor of knee flexion after TKA. Greater reduction in ACH was associated with improved flexion after TKA, whereas an increase in postoperative ACH may be a risk factor for flexion loss.

Epidemiology of Total Ankle Arthroplasty: Trends in New York State.

The rate of total ankle arthroplasty (TAA) is increasing in the United States as its popularity and indications expand. There currently is no national joint registry available to monitor outcomes, and few studies have addressed the challenges faced with TAA. The purpose of this study was to evaluate the incidence, complications, and survival rates associated with TAA using a large statewide administrative discharge database. Individuals who underwent primary TAA from 1997 to 2010 were identified in the Statewide Planning and Research Cooperative System database from the New York State Department of Health. The age, sex, comorbidities, state of residence, primary diagnosis, and readmissions within 90 days were analyzed for patients with an ICD-9-CM procedure code of 81.56 (TAA). Failure of a TAA implant was defined as revision, tibiotalar arthrodesis, amputation, or implant removal. During the 14-year period, 420 patients underwent 444 TAAs (mean patient age of 61 years, 59% women, mean Charlson-Deyo comorbidity score of 0.45, and 86% New York State residents). The primary diagnosis was 37.4% osteoarthritis, 34.3% traumatic arthritis, and 15.5% rheumatoid arthritis. Surgery for failure was associated only with a younger age (56.5 vs 62 years, P=.005). The rate of subsequent failure procedures following TAAs performed in New York State was 13.8%. The incidence of TAAs is steadily increasing. The overall survival rate in New York State is better than rates reported in other national registries, but it is not yet comparable to those of hip and knee replacements. [Orthopedics. 2016; 39(3):170-176.].

The increased utilization of operating room time in patients with increased BMI during primary total hip arthroplasty.

While obesity is associated with increased need for total hip arthroplasty (THA), the relationship between body mass index (BMI) and operative duration is unknown. We reviewed a series of 425 primary THAs implanted by one surgeon from 2004 to 2010. Patients were grouped by BMI based on the World Health Organization's categorization. Intraoperative time measurements (Total Room Time, Anesthesia Induction Time, Surgery Time) were compared across groups. Mean times were analyzed using a one-way ANOVA with post-hoc least squares difference test. Operating time increased progressively with increasing BMI category. Significant differences were found between normal weight patients and all 3 obesity groups in total room and surgery times. Obese patients spend more time in the OR during THA, reflecting the burden obesity poses to surgeons and hospitals.

Mini-midvastus vs standard medial parapatellar approach: a prospective, randomized, double-blinded study in patients undergoing bilateral total knee arthroplasty.

The purpose of this study was to determine whether the mini-midvastus approach to total knee arthroplasty (TKA) results in differences in quadriceps muscle strength as well as previously cited advantages in a double blind prospective randomized trial. Twenty-seven patients (54 TKAs) scheduled for bilateral TKA were randomized to undergo mini-midvastus approach on one knee and standard approach on the other. Incision lengths were the same. Postoperative strength was determined by isokinetic and isometric peak torque testing. Range of motion, pain Visual analog scale, side-preference, and gait analysis were assessed preoperatively and postoperatively. The only significant difference in strength testing was increased isokinetic and isometric extension torque at 3 weeks postoperatively for the mini-midvastus approach. No differences between the mini-midvastus and standard approach were observed for stride length, stance time, pain Visual analog scale, or knee range of motion. The mini-midvastus approach has limited benefit compared to the standard approach for TKA.