Men and Women Demonstrate Differences in Early Functional Recovery After Total Knee Arthroplasty

The effect of virtual reality on pain, kinesiophobia and function in total knee arthroplasty patients: A randomized controlled trial

BACKGROUND

Virtual reality (VR) has emerged as a promising new therapeutic approach, showing promise in the treatment of patients with a variety of diseases. This study aimed to investigate the effect of VR on pain, kinesiophobia, and function in patients undergoing total knee arthroplasty (TKA).

METHODS

This randomized controlled trial was performed on patients who had TKA due to osteoarthritis at Gazi University Hospital from October 2019 to August 2021. For this study, 21 female TKA patients were divided into two groups by the blocked randomization method: VR (n = 10) and exercise (n = 11). The exercise group was given a home exercise program. The VR group received immersive VR application in addition to the exercise. Pain, kinesiophobia, pain catastrophizing, knee range of motion, functional status, and quality of life were assessed. The Wilcoxon Test and Mann-Whitney U Test were used for comparison of the results.

RESULTS

The VR group had a statistically significant difference in the intensity of pain at rest, at night, and during the Timed Up and Go Test (TUG), kinesiophobia, pain catastrophizing, active knee flexion, the TUG, and the stair-climb test scores (P = 0.005 (95% confidence interval (CI) (-5.000, -1.000)), P = 0.005 (95% CI (-7.000, -2.000)), P = 0.023 (95% CI (-4.000, 0)), P = 0.006 (95% CI (-15.000, -3.000)), P = 0.012 (95% CI (-19.000, -3.000)), P = 0.010 (95% CI (4.000, 17.333)), P = 0.017 (95% CI (-14.700, -0.850)), P = 0.011 (95% CI (-23.100, -1.000)), respectively).

CONCLUSION

In the early period following total knee arthroplasty, using virtual reality integrated with exercise helps to reduce pain, kinesiophobia and pain catastrophizing, and to improve functional outcomes in female patients.

Clinical Interpretability of Quadriceps Strength and Gait Speed Performance in Total Knee Arthroplasty: A Longitudinal Study

OBJECTIVE

After a total knee arthroplasty, physical assessments of quadriceps strength and gait speed performance are often undertaken during rehabilitation. Our study aimed to improve their clinical interpretability by examining trajectory curves across levels of self-reported walking and stair climbing function.

DESIGN

A sample of 2624 patients with primary total knee arthroplasty participated in this retrospective longitudinal study. Monthly, for 4 mos after surgery, quadriceps strength and gait speed were quantified. At the month-6 time point, self-reported walking and stair climbing function was measured.

RESULTS

All physical measures improved nonlinearly over time. In mixed-effects models, greater quadriceps strength and gait speed over time were associated with higher month-6 self-reported walking and stair climbing function ( P < 0.001). Steeper gains in quadriceps strength and gait speed were associated with higher levels of walking and stair-climbing function (interaction P < 0.001). Among female patients who had great difficulty with stair ascent and ambulation, quadriceps strength trajectory curves plateaued after 8 wks after total knee arthroplasty.

CONCLUSIONS

By stratifying trajectory curves across clinically interpretable functional levels, our findings potentially provide patients and clinicians a means to better interpret the continuous-scaled quadriceps strength and gait speed values. This information may be valuable when engaging patients in shared decision making and expectation setting.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME.

CME OBJECTIVES

Upon completion of this article, the reader should be able to: (1) Understand how self-reported walking and stair climbing abilities improved from baseline before total knee arthroplasty (total knee arthroplasty) to 6 mos postoperatively; (2) Describe the time course of the 2 performance-based measures of quadriceps strength and walking speed after a total knee arthroplasty; and (3) Relate the trajectories of post-total knee arthroplasty quadriceps strength and walking speed measurements across distinct levels of self-reported walking and stair climbing function.

LEVEL

Advanced.

ACCREDITATION

The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s) ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Improvement Trajectories in Patient-Reported Outcomes Between Males and Females After Anterior Cruciate Ligament Reconstruction

CONTEXT

Patient-reported outcomes (PROs) are used to track recovery and inform clinical decision-making after anterior cruciate ligament reconstruction (ACLR). Whether sex influences the trajectory of improvements in PROs over time post-ACLR remains unclear.

OBJECTIVES

To (1) examine the effect of sex on the association between months post-ACLR and Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life (QOL) scores in individuals with ACLR and (2) assess sex differences in the KOOS QOL score at selected timepoints post-ACLR.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 133 females (20± 3 years) and 85 males (22 ± 4 years) within 6 to 60 months of primary, unilateral ACLR.

MAIN OUTCOME MEASURE(S)

The KOOS QOL was completed at a single follow-up timepoint post-ACLR. A multivariate linear regression model was calculated to assess the interaction of sex on the association between months post-ACLR and KOOS QOL score. Sex-specific linear regression models were then used to predict KOOS QOL estimated marginal means at each clinical timepoint (6, 12, 24, 36, 48, and 60 months post-ACLR) and compare the sexes.

RESULTS

In the primary model (R2 = 0.16, P < .0001), a significant interaction existed between sex and time post-ACLR (β = -0.46, P < .01). Greater months post-ACLR were associated with better KOOS QOL scores for males (R2 = 0.29, β = 0.69, P < .001); months post-ACLR was a weaker predictor of KOOS QOL scores for females (R2 = 0.04, β = 0.23, P < .02). Estimated marginal means for KOOS QOL scores were greater for males than females at 36 months (t210 = 2.76, P < .01), 48 months (t210 = 3.02, P < .01), and 60 months (t210 = 3.09, P = .02) post-ACLR.

CONCLUSIONS

Males exhibited PRO improvement post-ACLR as the months post-ACLR increased, whereas females did not demonstrate the same magnitude of linear increase in KOOS QOL score. Females may require extended intervention to improve clinical outcomes post-ACLR and address a plateau in QOL score.

Development of reference charts for monitoring quadriceps strength with handheld dynamometry after total knee arthroplasty

Purpose: To develop reference charts that describe normative quadriceps strength recovery after total knee arthroplasty (TKA) as measured by handheld dynamometry (HHD).Materials and Methods: We conducted a retrospective analysis of post-TKA quadriceps strength recovery in a longitudinal dataset consisting of both clinical and research HHD data. We created sex-specific models for recovery using Generalized Additive Models for Location, Scale, and Shape. We created reference charts from the models to display the recovery of population centiles over the first six postoperative months.Results: A total of 588 patient records with 1176 observations were analyzed. Reference charts for both sexes demonstrated a rapid increase in quadriceps strength over the first 60 postoperative days followed by a more gradual increase over the next 120 days. Males appeared to demonstrate faster recovery and greater strength on average compared to females. The quadriceps strength recovery of three female patient records was plotted on the reference chart to illustrate the charts' potential clinical utility.Conclusions: These reference charts provide normative data for quadriceps strength recovery after TKA as assessed by HHD. The reference charts may augment clinicians' ability to monitor and intervene upon quadriceps weakness-a pronounced and debilitating post-TKA impairment-throughout rehabilitation.Implications for RehabilitationHandheld dynamometry (HHD) is an objective and clinically feasible method for assessing muscle strength, but normative HHD values are lacking for quadriceps strength recovery after total knee arthroplasty (TKA).We created sex-specific reference charts which provide normative quadriceps strength HHD values for the first 180 days after TKA.These reference charts may improve clinicians' ability to monitor and intervene upon post-TKA quadriceps strength deficits.

What matters to patients following total knee arthroplasty? A grounded theory of adapting to a knee replacement

Background

Globally the volume of total knee arthroplasty (TKA) is on the rise, reflecting aging populations, an associated increase in treatment of osteoarthritis, and a desire for improved quality of life. There is evidence that as high as 15 to 20% of patients are not satisfied with their TKA results and efforts need to be made to improve these rates. This study set out to identify what patients consider important when reflecting on TKA satisfaction, to pave the way to identifying service transformation opportunities that will enhance patient-centred care and satisfaction with this procedure.

Methods

Twenty-seven TKA recipients were recruited in the province of British Columbia, Canada. Semi-structured interviews were conducted about participants’ experience and satisfaction with TKA, three to four years post-surgery. Grounded theory was employed to analyze participants’ stories about what was front of mind when they reflected on satisfaction with their new knee.

Results

Participants described their post-TKA knee in terms its adequacy: how it felt and worked, and how it matched their pre-surgical expectations. The central element of their stories was the process of adapting, which gave rise to their perceptions of adequacy. Adapting comprises the patient experience of physically integrating and cognitively accepting their new knee. Patterns of adapting reflect the level of the new knee’s achieved adequacy and the straightforwardness of the adapting process.

Discussion

The conceptualization of adequacy and the process of adapting allow a patient-centred understanding of what patients experience following TKA. For participants who did not readily achieve the adequacy they had anticipated, the challenges they experienced during adapting dominated their stories. Participants’ adapting stories afford key insights into how the health care system could adjust to better support TKA patients, and improve rates of satisfaction with this procedure.

Conclusions

The process of adapting lends itself to system intervention in support of enhanced post-TKA outcomes and satisfaction. These interventions could include the development of a care model including long-term clinical support for patients whose knees do not achieve desired results on schedule, and collaborating with patients to set and manage reasonable expectations about how their post-TKA knee will feel and function.

The Time Course of Quadriceps Strength Recovery After Total Knee Arthroplasty Is Influenced by Body Mass Index, Sex, and Age of Patients: Systematic Review and Meta-Analysis

Introduction

For patients with osteoarthritis who have undergone total knee arthroplasty (TKA), quadriceps strength is a major determinant of general physical function regardless of the parameters adopted for functional assessment. Understanding the time course of quadriceps strength recovery and effectiveness of different rehabilitation protocols is a must. Therefore, the aim of this study was to: (i) determine the magnitude of maximal voluntary strength (MVS) loss and the time course of recovery of the quadriceps muscle following TKA, (ii) identify potential moderators of strength outcomes, and (iii) investigate whether different rehabilitation practices can moderate the strength outcomes following TKA, respectively.

Design

General scientific databases and relevant journals in the field of orthopedics were searched, identifying prospective studies that investigated quadriceps’ MVS pre-to post-surgery.

Results

Seventeen studies with a total of 832 patients (39% males) were included. Results showed that in the early post-operative days, the involved quadriceps’ MVS markedly declined, after which it slowly recovered over time in a linear fashion. Thus, the greatest decline of the MVS was observed 3 days after TKA. When compared to pre-operative values, the MVS was still significantly lower 3 months after TKA and did not fully recover up to 6 months following TKA. Furthermore, a meta-regression analysis identified that the variables, time point of evaluation, patient age, sex, and BMI, significantly moderate the MVS of the quadriceps muscle.

Conclusion

The analyzed literature data showed that the decrease in strength of the involved quadriceps muscles following TKA is considerable and lasts for several months post-surgery. Therefore, we recommend to specifically target the strengthening of knee extensor muscles, preserve motor control, and apply appropriate nutrition to ensure a holistic quadriceps muscle recovery. Since age, sex, and BMI were found to be moderating factors in patients’ recovery, further research should include specific analyses considering these moderators.

Innate Immunity at the Core of Sex Differences in Osteoarthritic Pain?

Osteoarthritis (OA) is a progressive whole-joint disease; no disease-modifying drugs are currently available to stop or slow its process. Symptoms alleviation is the only treatment option. OA is the major cause of chronic pain in adults, with pain being the main symptom driving patients to seek medical help. OA pathophysiology is closely associated with the innate immune system, which is also closely linked to pain mediators leading to joint pain. Pain research has shown sex differences in the biology of pain, including sexually dimorphic responses from key cell types in the innate immune system. Not only is OA more prevalent in women than in men, but women patients also show worse OA outcomes, partially due to experiencing more pain symptoms despite having similar levels of structural damage. The cause of sex differences in OA and OA pain is poorly understood. This review provides an overview of the involvement of innate immunity in OA pain in joints and in the dorsal root ganglion. We summarize the emerging evidence of sex differences regarding innate immunity in OA pain. Our main goal with this review was to provide a scientific foundation for future research leading to alternative pain relief therapies targeting innate immunity that consider sex differences. This will ultimately lead to a more effective treatment of pain in both women and men.

Functional characteristics of female patients based on ambulatory ability 1 year after total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is commonly performed to reduce knee pain and improve physical function. Compared with the values for healthy, age-matched women, previous studies have reported large deficits in functional ability, such as muscle strength and ambulatory ability, in women 1 year post-TKA. Ambulatory ability is to move around, particularly by walking and is clinically assessed by the timed up and go test (TUG).

AIM

This study aimed to clarify the characteristics of knee functions in female patients whose ambulatory ability recovered to a normal level at 1 year after TKA.

METHODS

This cross-sectional study included 151 female patients who underwent TKA. The muscle strength of the lower extremity was measured, and the 2011 Knee Society Scoring (2011 KSS) system was used postoperatively. The TUG was conducted to assess ambulatory ability after TKA; then the patients were classified into the fast and slow ambulation groups based on previously reported gait-speed values of healthy female individuals. Then, we identified significant indicators of ambulatory ability at 1 year after TKA.

RESULTS

Forty-nine percent of patients after TKA achieved the level of ambulatory ability of a healthy female. Logistic regression analysis identified that the non-operative side knee extensor strength and the functional activity score, as assessed by the 2011 KSS, were variables significantly associated with the mid-term ambulatory ability after TKA.

CONCLUSION

Female patients with high non-operative knee extensor strength and a functional activity score at 1 year postoperatively can achieve better ambulatory ability than those of healthy, age-matched females.

Gender and Sex Are Key Determinants in Osteoarthritis Not Only Confounding Variables. A Systematic Review of Clinical Data

Many risk factors for osteoarthritis (OA) have been noted, while gender/sex differences have been understated. The work aimed to systematically review literature investigating as primary aim the relationship between gender/sex related discriminants and OA. The search was performed in PubMed, Science Direct and Web of Knowledge in the last 10 years. Inclusion criteria were limited to clinical studies of patients affected by OA in any joints, analyzing as primary aim gender/sex differences. Exclusion criteria were review articles, in vitro, in vivo and ex vivo studies, case series studies and papers in which gender/sex differences were adjusted as confounding variable. Of the 120 records screened, 42 studies were included. Different clinical outcomes were analyzed: morphometric differences, followed by kinematics, pain, functional outcomes after arthroplasty and health care needs of patients. Women appear to use more health care, have higher OA prevalence, clinical pain and inflammation, decreased cartilage volume, physical difficulty, and smaller joint parameters and dimensions, as compared to men. No in-depth studies or mechanistic studies analyzing biomarker differential expressions, molecular pathways and omic profiles were found that might drive preclinical and clinical research towards sex-/gender-oriented protocols.

Determination of reference intervals for knee motor functions specific to patients undergoing knee arthroplasty

Background

In patients with knee osteoarthritis (KOA) undergoing knee arthroplasty (KA), lower-limb motor function tests are commonly measured during peri-surgical rehabilitation. To clarify their sources of variation and determine reference intervals (RIs), a multicenter study was performed in Japan.

Methods

We enrolled 545 KOA patients (127 men; 418 women; mean age 74.2 years) who underwent KA and followed a normal recovery course. The surgical modes included total KA (TKA), minimally invasive TKA (MIS-TKA), and unicompartmental KA (UKA). Motor functions measured twice before and two weeks after surgery included timed up-and-go (TUG), maximum walking speed (MWS), extensor and flexor muscle strength (MS), and knee range of motion (ROM). Multiple regression analysis was performed to evaluate their sources of variation including sex, age, BMI, and surgical mode. Magnitude of between-subgroup differences was expressed as SD ratio (SDR) based on 3-level nested ANOVA. SDR≥0.4 was set as the threshold for requiring RIs specific for each subgroup.

Results

Before surgery, age-related changes exceeding the threshold were observed for TUG and MWS. Between-sex difference was noted for extensor and flexor MS, but extension and flexion ROMs were not influenced by sex or age. After surgery, in addition to similar influences of sex and age on test results, surgical modes of UKA and MIS-TKA generally had a favorable influence on MWS, extensor MS, and flexion ROM. All motor function test results showed a variable degree of skewness in distribution, and thus RIs were basically derived by the parametric method after Gaussian transformation of test results.

Conclusions

This is the first study to determine RIs for knee motor functions specific to KOA patients after careful consideration of their sources of variation and distribution shapes. These RIs facilitate objective implementation of peri-surgical rehabilitation and allow detection of patients who deviate from the normal course of recovery.

Peripheral Nociception Is Associated with Voluntary Activation Deficits and Quadriceps Weakness Following Total Knee Arthroplasty

BACKGROUND

Quadriceps weakness is a hallmark of total knee arthroplasty and is driven by reduced voluntary muscle activation following the surgical procedure. The mechanisms underlying postoperative activation deficits are not well established, although nociception has been implicated via both spinal reflex and supraspinal pathways. The purpose of this study was to assess the role of nociception in postoperative recovery of strength and activation.

METHODS

A total of 53 participants were assessed prior to total knee arthroplasty and at 6 weeks postoperatively. Quadriceps strength was measured by maximum voluntary isometric contraction, and activation was measured by the doublet interpolation technique. The pressure-pain threshold was used to measure local sensitization (at the knee joint) and systemic sensitization (at the forearm). Changes in outcomes (strength and activation) were regressed against pressure-pain threshold measurements. Mediation analyses were planned for significant associations to investigate whether deficits in voluntary activation were implicated on a causal pathway between pressure-pain threshold measures and postoperative strength loss.

RESULTS

Knee pressure-pain threshold measures were significantly associated with reduced voluntary quadriceps activation (beta = -0.04; p = 0.009) and diminished quadriceps strength after total knee arthroplasty (beta = -0.07; p = 0.001). There was also a mediation effect of voluntary activation on the relationship between the knee pressure-pain threshold and quadriceps strength. After correcting for multiple comparisons, relationships between the forearm pressure-pain threshold and strength and activation did not reach significance.

CONCLUSIONS

The measures of local nociceptor sensitization were related to reduced strength and activation following total knee arthroplasty. This is consistent with a causal pathway linking increased firing of knee joint nociceptors to reduced activation and reduced strength. Future randomized studies should investigate whether peripherally directed pain therapies reduce pain while also promoting the recovery of quadriceps strength via an improved capacity for voluntary activation.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Do Sociodemographic Factors Relate to Walking Ability in Individuals Who Underwent Total Knee Arthroplasty?

BACKGROUND AND PURPOSE

Knee osteoarthritis is one of the most common health problems in older adults and total knee arthroplasty (TKA) is able to improve walking ability in these individuals. There have been few studies investigating whether sociodemographic factors influence walking ability after TKA. The aim of this study was to examine which sociodemographic factors relate to walking ability in Japanese older adults following TKA during the acute stage of recovery.

METHODS

This prospective cohort study included 388 participants, from a multicenter database, who underwent TKA. The Timed Up and Go test 2 weeks after TKA was the dependent variable. Sociodemographic factors including age, sex, body mass index, marital status, and academic qualification were independent variables. In addition, type of surgery and severity of osteoarthritis were measured as confounding variables. A hierarchical multiple regression analysis was used to predict the factors that have the greatest influence on walking ability. Models were examined with and without confounding factors.

RESULTS AND DISCUSSION

In the final regression model, older age, conventional TKA approaches, increased severity of Kellgren-Lawrence grade, and women were associated with longer Timed Up and Go time. Academic qualification and marital status were not related to walking ability.

CONCLUSIONS

Our results suggest that age, type of surgery, severity of osteoarthritis, and sex are related to Timed Up and Go time during the acute stage following TKA and need to be assessed.

The safety, efficacy and cost-effectiveness of the Maxm Skate, a lower limb rehabilitation device for use following total knee arthroplasty: study protocol for a randomised controlled trial

BACKGROUND

Physical rehabilitation is required to enhance functional outcomes and overall recovery following total knee arthroplasty (TKA). However, there are no universally accepted clinical guidelines available to consistently structure rehabilitation for TKA patients. A common method is rehabilitation provided in an outpatient setting, on a one-to-one treatment basis. This method is resource-intensive and outcomes must be compared to less costly alternatives such as home-based rehabilitation. The current study will analyse a novel home-based rehabilitation program. The Maxm skate is a portable, lower-limb, postoperative, rehabilitation exercise device for individual use in a hospital or home-based setting. This study was developed to compare the safety, efficacy and cost-effectiveness of the Maxm Skate rehabilitation program to standard rehabilitative care following TKA. The primary outcome is the range of motion (ROM) achieved by patients who received the Maxm Skate program compared to standard care at three months post TKA. Secondary outcomes include patient-reported outcomes, costs and functional evaluations which will be collected at multiple time-points up to 12 months after TKA.

METHODS

This is a single-blinded, randomised controlled trial (RCT) in which 116 eligible participants consented for primary TKA will be randomly allocated to receive either the Maxm Skate rehabilitation program or standard rehabilitative care. Fifty-eight participants per group will provide 90% power (α = 0.05) to detect 10° of difference in ROM between groups at three months after TKA, assuming a within-group standard deviation of 16° and allowing for 5% loss to follow-up. Participants randomised to the Maxm Skate group will use the skate device and accompanying iOS App and sensors to complete rehabilitation exercises, as outlined in the Maxm Skate Rehabilitation Guide. Outcomes will be compared to those receiving standard rehabilitative care. A blinded physiotherapist will evaluate functional outcomes preoperatively and at 2, 4, 6, 12, 26 and 52 weeks after TKA. The functional assessment will include measures of knee ROM, pain, isometric knee strength, balance and knee/thigh circumference. Limited measures will also be assessed at day 2 postoperatively by an alternate, unblinded physiotherapist. Clinical outcome measures will be administered preoperatively and at 6, 12 and 52 weeks postoperatively. An economic evaluation will be conducted and participants will be screened for adverse event occurrences from the time of consent to 12 months postoperatively.

DISCUSSION

This RCT will be the first to investigate the safety, efficacy and cost-effectiveness of the home-based Maxm Skate Rehabilitation program, in comparison to standard rehabilitative care following primary TKA.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12616001081404p . Registered on 11 August 2016.

Restoring physical function after knee replacement: a cross sectional comparison of progressive strengthening vs standard physical therapy

Objective: The purpose of this study is to compare the functional status of patients 12 months after total knee arthroplasty (TKA) who underwent progressive strengthening or standard of care rehabilitation to older adults without knee joint pain. Methods: This cross-sectional design study included 165 participants in the progressive strengthening group, 40 participants in the standard of care group, and 88 older adults (control group). The Knee Outcome Survey - Activity of Daily Living, knee active range of motion (ROM), quadriceps strength, and performance tests were compared between groups using a one-way ANOVA. The proportions of participants in both TKA groups who achieved the lower bound of the 95% confidence interval of the control group were compared using a Fisher's exact test. Results: Significant between-group effects were found for all variables (p < 0.001). The control group had better outcomes than both the progressive strengthening and standard of care groups (p < 0.001). Compared to the standard of care group, a higher proportion of participants in the progressive strengthening group achieved the lower bound cutoff for active knee extension ROM (p = 0.042), quadriceps strength (p = 0.032), and stair climbing time (p = 0.029). Conclusion: More participants in the progressive strengthening group had physical function that was similar to the healthy control group, when compared to the standard of care group. Progressive strengthening rehabilitation may be more effective in restoring normative levels of function after TKA than standard of care.

Age- and sex-based recovery curves to track functional outcomes in older adults with total knee arthroplasty

Background

older adults with total knee arthroplasty (TKA) frequently undergo rehabilitation to address limited knee flexion range-of-motion, quadriceps weakness and gait speed limitations. This study aimed to develop age- and sex-specific recovery curves of knee flexion range-of-motion, quadriceps strength and fast gait speed post-TKA.

Methods

a population-based sample of 2,987 patients undergoing primary TKA participated, of whom 2015 (68%) were 65 years of age or older. At 4, 8 and 12 weeks post surgery, knee flexion range-of-motion, quadriceps strength and fast gait speed were quantified. Quantile regression was used to determine the percentiles of the knee and gait measures.

Results

the various knee and gait measures improved nonlinearly over time, with substantial improvements observed in the 1st 8-10 weeks post surgery. Age-specific, sex-specific recovery curves were developed to show the recovery patterns at multiple percentile levels. A web interface was created to facilitate easy computation of the percentile rank for a given outcome value.

Conclusions

we have provided reference percentile values for knee flexion range-of-motion, quadriceps strength and gait speed recovery post-TKA. Such information may assist rehabilitation professionals in interpreting outcomes and quantifying deviations from the expected recovery pattern.

The Role of Patient Characteristics on the Choice of Unicompartmental versus Total Knee Arthroplasty in Patients With Medial Osteoarthritis

BACKGROUND

Medial unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are both viable treatment options for medial osteoarthritis (OA). However, it remains unclear when to choose for which arthroplasty treatment. Goals of this study were therefore to (1) compare outcomes after both treatments and (2) assess which treatment has superior outcomes in different patient subgroups.

METHODS

In this retrospective cohort study, 166 patients received the RESTORIS MCK Medial UKA and 63 patients the Vanguard TKA and were radiographically matched on isolated medial OA. Western Ontario and McMaster Universities Arthritis Index scores were collected preoperatively and postoperatively (mean: 3.0 years, range: 2.0-5.0 years).

RESULTS

Preoperatively, no differences were observed, but medial UKA patients reported better functional outcomes than TKA (89.7 ± 13.6 vs 81.2 ± 18.0, P = .001) at follow-up.Better functional outcomes were noted after medial UKA in patients younger than age 70 years (89.5 ± 14.2 vs 78.6 ± 20.0, P = .001), with body mass index below 30 (90.3 ± 11.4 vs 83.6 ± 14.9, P = .005), with body mass index above 30 (88.3 ± 17.5 vs 78.8 ± 21.0, P = .034) and in females (90.6 ± 11.0 vs 78.1 ± 19.4, P = .001) when compared with TKA. No differences were found in males and older patients between both arthroplasties.

CONCLUSION

Superior functional outcomes were noted after medial UKA over TKA in patients presenting with medial OA with these prostheses. Subgroup analyses suggest that medial UKA is the preferred treatment in younger patients and females while no differences were noted in older patients and males after medial UKA and TKA. This might help the orthopedic surgeon in individualizing arthroplasty treatment for patients with medial OA.

Moderate-intensity resistance exercise alters skeletal muscle molecular and cellular structure and function in inactive older adults with knee osteoarthritis

High-intensity resistance exercise (REX) training increases physical capacity, in part, by improving muscle cell size and function. Moderate-intensity REX, which is more feasible for many older adults with disease and/or disability, also increases physical function, but the mechanisms underlying such improvements are not understood. Therefore, we measured skeletal muscle structure and function from the molecular to the tissue level in response to 14 wk of moderate-intensity REX in physically inactive older adults with knee osteoarthritis (n = 17; 70 ± 1 yr). Although REX training increased quadriceps muscle cross-sectional area (CSA), average single-fiber CSA was unchanged because of reciprocal changes in myosin heavy chain (MHC) I and IIA fibers. Intermyofibrillar mitochondrial content increased with training because of increases in mitochondrial size in men, but not women, with no changes in subsarcolemmal mitochondria in either sex. REX increased whole muscle contractile performance similarly in men and women. In contrast, adaptations in single-muscle fiber force production per CSA (i.e., tension) and contractile velocity varied between men and women in a fiber type-dependent manner, with adaptations being explained at the molecular level by differential changes in myosin-actin cross-bridge kinetics and mechanics and single-fiber MHC protein expression. Our results are notable compared with studies of high-intensity REX because they show that the effects of moderate-intensity REX in older adults on muscle fiber size/structure and myofilament function are absent or modest. Moreover, our data highlight unique sex-specific adaptations due to differential cellular and subcellular structural and functional changes.NEW & NOTEWORTHY Moderate-intensity resistance training causes sex-specific adaptations in skeletal muscle structure and function at the cellular and molecular levels in inactive older adult men and women with knee osteoarthritis. However, these responses were minimal compared with high-intensity resistance training. Thus adjuncts to moderate-intensity training need to be developed to correct underlying cellular and molecular structural and functional deficits that are at the root of impaired physical function in this mobility-limited population.