Predicting Delayed In-Hospital Recovery of Physical Function After Total Knee Arthroplasty.

Objective: To identify patients at high risk of delayed in-hospital functional recovery after knee replacement surgery by developing and validating a prediction model, including a combination of preoperative physical fitness parameters and patient characteristics. Design: Retrospective cohort study using binary logistic regression. Setting: University hospital, orthopedic department. Participants: 260 adults (N=260) (≥18y) with knee osteoarthritis awaiting primary unilateral total knee arthroplasty and assessed during usual care between 2016 and 2020. Intervention: Not applicable. Main Outcome Measures: Time to reach in-hospital functional independence (in days), measured by the modified Iowa Level of Assistance Scale. A score of 0 means completely independent. Potential predictor variables are a combination of preoperative physical fitness parameters and patient characteristics. Results: Binary logistic regression modeling was applied to develop the initial model. A low de Morton Mobility Index (DEMMI), walking aid use indoors, and a low handgrip strength (HGS) were the most important predictors of delayed in-hospital recovery. This model was internally validated and had an optimism-corrected R2 of 0.07 and an area under curve of 61.2%. The probability of a high risk of delayed in-hospital recovery is expressed by the following equation:Phighrisk=(1/(1+e(-(2.638-0.193×DEMMI+0.879×indoorwalkingaid-0.007×HGS))))×100%. Conclusions: The model has a low predictive value and a poor discriminative ability. However, there is a positive association between preoperative physical fitness and postoperative recovery of physical function. The validity of our model to distinguish between high and low risk, based on preoperative fitness values and patient characteristics, is limited.

Limited predictive value of pre-surgical level of functioning for functioning at 3 and 12 months after TKA.

PURPOSE: A total knee arthroplasty (TKA) is a cost-effective option to relieve pain and improve knee function in patients suffering from osteoarthritis. However, results differ among patients. The predictive value of pre-surgically assessed factors on the level of functioning after 3 and 12 months was investigated in this study. METHODS: This study used an inception cohort design and a follow-up of 12 months. One hundred and fifty patients who were to receive a TKA were assessed pre-surgically with an International Classification of Functioning, Disability and Health (ICF) core assessment set: Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short-Form 12 (SF12), Patient-Specific Function Scale (PSFS), range of motion (ROM), quadriceps and hamstring strength and gait parameters. The main outcome measure was WOMAC-Function at 3 and 12 months after surgery. RESULTS: Pre-surgical physical and mental health on the SF12 and functioning and stiffness on the WOMAC explained 23% of the variance in the level of functioning 3 months after surgery. Pre-surgical knee function measured with the KSS-Knee, and functioning as assessed by WOMAC-Function explained 16% of the variance of the level of functioning 12 months after surgery. CONCLUSIONS: The results of this study show that better functioning before surgery, less knee stiffness and a better physical and mental health to some extent predict better functioning 3 months after surgery. This effect is less evident at 12 months. This study is clinically relevant since it provides benchmark data for health care providers who want to compare their individual patients. LEVEL OF EVIDENCE: II.

Functions, disabilities and perceived health in the first year after total knee arthroplasty; a prospective cohort study.

BACKGROUND: In end-stage knee osteoarthritis total knee arthroplasty (TKA) is an effective intervention to reduce pain and improve functioning in the majority of patients. However, after TKA some patients still experience pain, loss of function, deficient muscle strength or reduced walking speed. This study systematically assesses patients' functions, disabilities and health before TKA and at short- (3 months) and long-term (12 months) on all International Classification of Functioning, Disability and Health domains. METHODS: In this prospective cohort study 150 patients underwent the following tests before and at 3 and 12 months after surgery: Western Ontario and McMaster Universities Arthritis Index, Short Form 12, Knee Society Score, Patient Specific Functioning Scale, knee range of motion, quadriceps and hamstring strength, gait parameters, global perceived effect (only after surgery). All data was analyzed with repeated measures ANOVA for all measurement time points. RESULTS: Despite increased gait speed, quadriceps strength and scores on questionnaires being above pre surgical levels, patients do not reach levels of healthy persons. Walking speeds approach normal values and are higher in our study compared with the literature. Quadriceps strength stays at around 70 till 80% of norm values. However, dissatisfaction rates are below 10%, which is low compared to the literature. CONCLUSIONS: Quality of life, activities, muscle strength and gait parameters improve significantly after TKA. However, some complaints regarding activities and walking speed remain. Most striking outcome is the remaining deficit in quadriceps strength.

The Patient-Specific Functional Scale: Its Reliability and Responsiveness in Patients Undergoing a Total Knee Arthroplasty.

STUDY DESIGN: A prospective cohort study, with assessments before, at 3 months after, and at 12 months after total knee arthroplasty (TKA). OBJECTIVES: To determine and compare the responsiveness and reliability of the Patient-Specific Functional Scale (PSFS) in patients undergoing a TKA. BACKGROUND: Reliable and valid measurement instruments are important to measure functional status. The PSFS is frequently used in several patient populations, but its methodological characteristics in a population of patients with TKA in the perioperative phases of surgery are unknown. METHODS: The PSFS, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and global perceived effect (GPE) were administered at 3 time points in 150 patients undergoing a TKA. Correlations, effect sizes, and standardized response means were calculated. The PSFS was administered twice to assess its reliability in terms of intraclass correlation coefficients and limits of agreement. RESULTS: The correlation coefficients between the PSFS and WOMAC at 3 months and 1 year were 0.41 and 0.48, respectively; those between the PSFS and GPE were -0.37 and -0.55, respectively. The effect sizes of the PSFS at 3 months and 1 year were 1.71 and 2.89, respectively; those of the WOMAC were 1.45 and 1.64, respectively. The standardized response means of the PSFS at 3 months and 1 year were 0.96 and 1.48, respectively; those of the WOMAC were 1.28 and 1.37, respectively. The intraclass correlation coefficients ranged between 0.73 and 0.86. The systematic error was between 0.12 and 0.54. The limits of agreement ranged from ±2.17 to ±2.72. CONCLUSION: The reliability of the PSFS is good. Its responsiveness is high, especially in the long term. However, the PSFS cannot be used interchangeably with the WOMAC in the immediate postoperative period.