Effect of Weight Change on Patient-Reported Outcomes Following Total Joint Arthroplasty

Biomechanical improvements in gait following medial pivot knee implant surgery

BACKGROUND

Total knee replacements are used to improve function and reduce pain in patients with advanced osteoarthritis. The medially stabilising implant is designed to mimic a healthy knee. This study aims to provide a comprehensive analysis of the kinematics and kinetics of a medially stabilising knee implant, comparing it to a healthy control group, as well as to its pre-operative state and the contralateral limb.

METHODS

Sixteen total knee replacement patients and ten healthy participants were recruited. Patients underwent testing 4-6 weeks before surgery and repeated the same tests 12 months after surgery. Healthy participants completed the same tests at a single time point. All participants completed three walking trials: kinematics was captured with eight cameras; kinetics with in-ground force plates. Subject-specific musculoskeletal models were developed in OpenSim. Inverse kinematics and inverse dynamics were used to determine gait parameters. Joint angles and joint moments were evaluated using Statistical Parametric Mapping. Patient-reported outcome measures were also collected at both time points.

FINDINGS

Spatiotemporal results indicate significant differences in velocity and step length between pre-operative patients and control participants. Differences are observed in the adduction angles between the contralateral and ipsilateral limbs pre-operatively. Postoperatively, there was an increase in the 1st peak flexion moment, reduced adduction moment and reduced internal rotation moment. In PROMs, patients all report improvements in pain levels and high satisfaction levels following surgery.

INTERPRETATIONS

Following medial stabilising total knee arthroplasty, patients displayed improved clinical parameters and joint moments reflecting a shift towards more normal, healthy gait.

Preoperative and Postoperative Weight Change has Minimal Influence on Health Care Utilization and Patient-Reported Outcomes Following Total Knee Arthroplasty

As obesity becomes more prevalent, more patients are at risk of lower extremity osteoarthritis and subsequent total knee arthroplasty (TKA). This study aimed to test (1) the association of preoperative weight change with health care utilization and (2) the association of pre- and postoperative weight changes with failure to achieve satisfaction and minimal clinically important difference (MCID) in Knee injury and Osteoarthritis Outcome Score for pain (KOOS-Pain) and function (KOOS-PS) 1 year after TKA. Prospectively collected monocentric data on patients who underwent primary TKA were retrospectively reviewed. Multivariable logistic regression assessed the influence of BMI and weight change on outcomes while controlling for confounding variables. Outcomes included prolonged length of stay (LOS >3 days), nonhome discharge, 90-day readmission rate, satisfaction, and achievement of MCID for KOOS-Pain and KOOS-PS. Preoperative weight change had no impact on prolonged LOS (gain, p = 0.173; loss, p = 0.599). Preoperative weight loss was associated with increased risk of nonhome discharge (odds ratio [OR]: 1.47, p = 0.003). There was also increased risk of 90-day readmission with preoperative weight gain (OR: 1.27, p = 0.047) and decreased risk with weight loss (OR: 0.73, p = 0.033). There was increased risk of nonhome discharge with obesity class II (OR: 1.6, p = 0.016) and III (OR: 2.21, p < 0.001). Weight change was not associated with failure to achieve satisfaction, MCID in KOOS-Pain, or MCID in KOOS-PS. Obesity class III patients had decreased risk of failure to reach MCID in KOOS-Pain (OR: 0.43, p = 0.005) and KOOS-PS (OR: 0.7, p = 0.007). Overall, pre- and postoperative weight change has little impact on the achievement of satisfaction and clinically relevant differences in pain and function at 1 year. However, preoperative weight gain was associated with a higher risk of 90-day readmissions after TKA. Furthermore, patients categorized in Class III obesity were at increased risk of nonhome discharge but experienced a greater likelihood of achieving MCID in KOOS-Pain and KOOS-PS. Our results raise awareness of the dangers of using weight changes and BMI alone as a measure of TKA eligibility.

Non-White Race and Concomitant Orthopedic Conditions Are Risk Factors for Failure to Achieve Clinically Relevant Improvement After Total Knee Arthroplasty

BACKGROUND

Data from the American Joint Replacement Registry demonstrate that 1-year minimal clinically important difference (MCID) achievement rates after total knee arthroplasty (TKA) are substantially lower when using general patient reported outcome measures, such as Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), than joint specific measures. The purpose of this study was to evaluate patient characteristics and outcomes associated with MCID achievement after TKA using the PROMIS-PF measure.

METHODS

A retrospective review of 263 patients undergoing TKA with preoperative and 1-year postoperative PROMIS-PF scores from March 12, 2020 to February 8, 2022 was performed. Three multivariate models were built to evaluate predictors of MCID achievement. Preoperative predictors evaluated included demographics, comorbidities, history of spine and knee surgery, and baseline PROMIS-PF. Postoperative clinical outcomes evaluated included lengths of stay, discharge statuses, complications, and utilizations of other orthopaedic services.

RESULTS

There were 109 patients (41%) who achieved an MCID at 1-year postoperatively. Non-white patients had 2.17 times lower odds of achieving MCID. No clinical outcomes assessed were independently predictive of MCID achievement. During the 1-year postoperative period, 63% of patients sought care for another orthopaedic condition. Patients requiring postoperative injections on another joint had a 2.27 times lower odds of achieving MCID. Those seen for spine conditions postoperatively had a 2.44 lower odds of achieving MCID.

CONCLUSIONS

Race, postoperative injections, and treatment for spine conditions after TKA were independent predictors of failure to achieve MCID. These results may guide preoperative patient consultation and risk-adjustment in future studies using PROMIS-PF as an endpoint for evaluation of TKA outcomes.

Does Your Patient Need to Lose Weight? Weight Change Before and After Total Hip Arthroplasty Does Not Affect Health Care Utilization and Achievement of the Minimal Clinically Important Difference

BACKGROUND

Despite the potential negative impact of preoperative obesity on total hip arthroplasty (THA) outcomes, the association between preoperative and postoperative weight change and outcomes is much less understood. Therefore, this study aimed to determine the impact of preoperative and postoperative weight change and preoperative body mass index (BMI) on health care utilization, satisfaction, and achievement of minimal clinically important difference (MCID) for Hip Disability and Osteoarthritis Outcome Score Physical Function Short-Form (HOOS PS) and HOOS Pain.

METHODS

Patients who underwent primary elective unilateral THA between January 2016 and December 2019 were included (N = 2,868). Multivariable logistic regression assessed the association between BMI and preoperative and postoperative weight change on outcomes while controlling for demographic characteristics.

RESULTS

There was no association between preoperative weight change and prolonged length of stay (> 3 days), 90-day readmission, nonhome discharge, patient dissatisfaction at 1 year, or achievement of HOOS Pain or HOOS PS MCID. Postoperative weight loss was an independent risk factor for patient dissatisfaction at 1 year but was not associated with achievement of either HOOS Pain or HOOS PS MCID at 1-year postoperative. Preoperative obesity classes I to III were independent risk factors for nonhome discharge. Nevertheless, preoperative obesity class I and class II were associated with an increased probability of reaching HOOS Pain MCID. Preoperative BMI was not associated with an increased risk of patient dissatisfaction.

CONCLUSIONS

Preoperative weight change does not appear to influence health care utilization, satisfaction, or achievement of MCID in pain and function following THA. Postoperative weight loss may play a role as a risk factor for dissatisfaction following THA. Additionally, patients who had a higher baseline BMI may be more likely to see improvement in pain following THA. Therefore, when counseling obese patients for THA, surgeons must balance the risk of perioperative complications with the expectation of greater improvements in pain.

Intersurgeon Variability of Minimal Clinically Important Difference for Worsening Achievement Rates After Total Joint Arthroplasty

BACKGROUND

Using the Patient-Reported Outcome Measurement Information System, we sought to evaluate surgeon performance variability via minimal clinically important difference for worsening (MCID-W) achievement rates in primary and revision total knee and hip arthroplasty.

METHODS

This retrospective study analyzed 3,496 primary total hip arthroplasty (THA), 4,622 primary total knee arthroplasty (TKA), 592 revision THA, and 569 revision TKA patients. Patient factors collected included demographics, comorbidities, and Patient-Reported Outcome Measurement Information System physical function short form 10a scores. Surgeon factors collected included caseload, years of experience, and fellowship training. The MCID-W rate was calculated as the percent of patients in each surgeon's cohort who achieved MCID-W. Distribution was presented via a histogram with associated average, standard deviation, range, and interquartile range (IQR). Linear regressions were performed to evaluate the potential correlation between surgeon- and patient-level factors with MCID-W rate.

RESULTS

The average MCID-W rates of the surgeons represented in the primary THA and TKA cohorts were 12.7 ± 9.2% (range, 0 to 35.3%; IQR, 6.7 to 15.5%) and 18.0 ± 8.2% (range, 0 to 36%; IQR, 14.3 to 22.0%). The average MCID-W rates among the revision THA and TKA surgeons were 36.0 ± 22.2% (range, 9.1 to 90%; IQR, 25.0 to 41.4%) and 21.2 ± 7.7% (range, 8.1 to 37.0%; IQR, 16.6 to 25.4%). Strong correlations were not found between patient- or surgeon-level factors and MCID-W rate of the surgeon.

CONCLUSION

We demonstrated variance in MCID-W achievement rates across surgeons in both primary and revision joint arthroplasty, independent of patient- or surgeon-level factors.

Predictors for activity following total and unicompartmental knee arthroplasty

BACKGROUND

Functional demands of patients undergoing knee arthroplasty are increasing. However, it remains unclear which patient-specific factors have an impact on postoperative activity and whether there is a difference between total and unicompartmental knee arthroplasties (TKA/UKA).

MATERIALS AND METHODS

This retrospective study analyzed 1907 knees with TKA (n = 1746) or UKA (n = 161), implanted for primary osteoarthritis. Pain and activity (lower extremity activity scale, LEAS) were assessed 2 years after surgery. High activity was defined as LEAS ≥ 14. Cohorts were compared using Kruskal-Wallis or Pearson-Chi-square test. A generalized least squares model was used to predict LEAS scores between cohorts adjusted for age, sex, BMI, Charlson Comorbidity Index, ASA score, and preoperative LEAS.

RESULT

There was no difference in pain 2 years after surgery between UKA and TKA (p = 0.952). Preoperative LEAS was similar for UKA and TKA (p = 0.994), and both groups showed significant (p < 0.001 respectively) and similar improvements after surgery (p = 0.068). LEAS 2 years after surgery was 11.1 (SD 3.2) for TKA and 11.9 (SD 3.5) for the UKA group (p = 0.004). After adjusting for preoperative LEAS, age, sex, BMI, CCI and ASA, the difference was not significant (p = 0.225). Male sex, lower BMI, higher preoperative LEAS, and younger age were associated with higher postoperative LEAS (p < 0.001, respectively).

CONCLUSION

Patients can achieve a high level of activity following both TKA and UKA. While the postoperative activity level did not depend on the type of the procedure, younger age, male sex, lower BMI, and a higher preoperative activity level were associated with a higher postoperative activity level.