High-intensity interval training, but not continuous training, reverses right ventricular hypertrophy and dysfunction in a rat model of pulmonary hypertension.

Exercise is beneficial in pulmonary arterial hypertension (PAH), although studies to date indicate little effect on the elevated pulmonary pressures or maladaptive right ventricle (RV) hypertrophy associated with the disease. For chronic left ventricle failure, high-intensity interval training (HIIT) promotes greater endothelial stimulation and superior benefit than customary continuous exercise training (CExT); however, HIIT has not been tested for PAH. Therefore, here we investigated acute and chronic responses to HIIT vs. CExT in a rat model of monocrotaline (MCT)-induced mild PAH. Six weeks of treadmill training (5 times/wk) were performed, as either 30 min HIIT or 60 min low-intensity CExT. To characterize acute hemodynamic responses to the two approaches, novel recordings of simultaneous pulmonary and systemic pressures during running were obtained at pre- and 2, 4, 6, and 8 wk post-MCT using long-term implantable telemetry. MCT-induced decrement in maximal aerobic capacity was ameliorated by both HIIT and CExT, with less pronounced pulmonary vascular remodeling and no increase in RV inflammation or apoptosis observed. Most importantly, only HIIT lowered RV systolic pressure, RV hypertrophy, and total pulmonary resistance, and prompted higher cardiac index that was complemented by a RV increase in the positive inotrope apelin and reduced fibrosis. HIIT prompted a markedly pulsatile pulmonary pressure during running and was associated with greater lung endothelial nitric oxide synthase after 6 wk. We conclude that HIIT may be superior to CExT for improving hemodynamics and maladaptive RV hypertrophy in PAH. HIIT's superior outcomes may be explained by more favorable pulmonary vascular endothelial adaptation to the pulsatile HIIT stimulus.

Incorporating Functional Strength Integration Techniques During Total Hip Arthroplasty Rehabilitation: A Randomized Controlled Trial.

OBJECTIVE: Total hip arthroplasty (THA) is a common orthopedic procedure that alleviates pain for millions of individuals. Yet, persistent physical function deficits, perhaps associated with movement compensations, are observed after THA. These deficits negatively affect quality of life and health for many individuals. Functional strength integration (FSI) techniques combine muscle strength training with specific movement retraining to improve physical function. This study aimed to determine if FSI would improve functional performance through remediation of movement compensations for individuals after THA. METHODS: A double-blind randomized controlled trial was conducted. Ninety-five participants were randomized to either the FSI or control (CON) group for an 8-week intervention. The FSI protocol included exercise to improve muscular control and stability around the hip to minimize movement compensation during daily activity. The CON protocol included low-load resistance exercise, range-of-motion activities, and patient education. Functional performance, muscle strength, and self-reported outcomes were measured preoperatively, midway and after intervention, and 6 months after THA. Change from preoperative assessment to each time point was measured, and between-group differences were assessed. RESULTS: There were minimal differences in outcomes between groups at the first postoperative assessment. There were no statistically significant between-group differences in the later assessments, including the primary endpoint. Both groups improved functional outcomes throughout the study period. CONCLUSION: The FSI intervention did not result in greater improvements in function after THA compared to the CON intervention. Future work should further investigate additional biomechanical outcomes, timing of the FSI protocol, effective dosing, and patient characteristics predictive of success with FSI. IMPACT: Recovery after THA is complex, and individuals after THA are affected by persistent movement deficits that affect morbidity and quality of life. The present study suggests that either approach to THA rehabilitation could improve outcomes for patients, and that structured rehabilitation programs may benefit individuals after THA.

Expert Consensus for the Use of Outpatient Rehabilitation Visits After Total Knee Arthroplasty: A Delphi Study.

OBJECTIVE: There is no consensus for how to use rehabilitation visits after total knee arthroplasty (TKA). We sought to develop expert recommendations for outpatient rehabilitation visit usage after TKA. DESIGN: Delphi study. METHODS: First, we developed a broad list of preliminary visit usage recommendations, which were specific to patients' recovery status (ie, slow, typical, or fast recovery) and time since surgery. We then invited 49 TKA experts to participate on a Delphi panel. During round 1, we surveyed panelists regarding their level of agreement with each preliminary recommendation. We conducted additional Delphi rounds as needed to build consensus, which we defined using the RAND/UCLA method. We updated the survey each round based on panelist feedback and responses from the previous round. RESULTS: Thirty panelists agreed to participate, and 29 panelists completed 2 Delphi rounds. The panel reached consensus on recommendations related to visit frequency, visit timing, and the use of telerehabilitation. The panel recommended that outpatient rehabilitation should begin within 1 week after surgery at a frequency of 2 times per week for the first postoperative month regardless of recovery status. The panel recommended different visit frequencies depending on the patient's recovery status for postoperative months 2 to 3. The panel agreed that telerehabilitation can be recommended for most patients after TKA, but not for patients recovering slowly. CONCLUSION: We used the Delphi process to develop expert recommendations for the use of outpatient rehabilitation visits after TKA. We envision these recommendations could help patients decide how to use visits based on their own preferences. J Orthop Sports Phys Ther 2023;53(9):1-9. Epub: 10 July 2023. doi:10.2519/jospt.2023.11840.

Neuromuscular electrical stimulation preserves muscle strength early after total knee arthroplasty: Effects on muscle fiber size.

Loss of quadriceps strength after total knee arthroplasty (TKA) is most pronounced acutely but persists long-term, negatively impacting physical function in daily activities. Neuromuscular electrical stimulation (NMES) early after surgery is an effective adjuvant to standard of care rehabilitation (SOC) for attenuating strength loss following TKA, but the mechanisms whereby NMES maintains strength are unclear. This work aimed to determine the effects of early NMES on quadriceps strength and skeletal muscle fiber size 2 weeks after TKA compared to SOC. Patients scheduled for primary, unilateral TKA were enrolled and randomized into SOC (n = 9) or NMES plus SOC (n = 10) groups. NMES was started within 48 h of TKA, with 45-min sessions twice a day for 2 weeks. Isometric quadriceps strength was assessed preoperatively and 2 weeks following TKA. Vastus lateralis muscle biopsies of the involved leg were performed at the same time points and immunohistochemistry conducted to assess muscle fiber cross-sectional area and distinguish fiber types. Groups did not differ in age, body mass index, sex distribution, or preoperative strength. Both groups got weaker postoperatively, but the NMES group had higher normalized strength. After 2 weeks, the group receiving NMES and SOC had significantly greater MHC IIA and MHC IIA/IIX fiber size compared to SOC alone, with no group differences in MHC I fiber size. These results suggest that NMES mitigates early muscle weakness following TKA, in part, via effects on fast-twitch, type II muscle fiber size. This investigation advances our understanding of how adjuvant, early postoperative NMES aids muscle strength recovery.

Comparing "people-like-me" and linear mixed model predictions of functional recovery following knee arthroplasty.

OBJECTIVE: Prediction models can be useful tools for monitoring patient status and personalizing treatment in health care. The goal of this study was to compare the relative strengths and weaknesses of 2 different approaches for predicting functional recovery after knee arthroplasty: a neighbors-based "people-like-me" (PLM) approach and a linear mixed model (LMM) approach. MATERIALS AND METHODS: We used 2 distinct datasets to train and then test PLM and LMM prediction approaches for functional recovery following knee arthroplasty. We used the Timed Up and Go (TUG)-a common test of mobility-to operationalize physical function. Both approaches used patient characteristics and baseline postoperative TUG values to predict TUG recovery from days 1-425 following surgery. We then compared the accuracy and precision of PLM and LMM predictions. RESULTS: A total of 317 patient records with 1379 TUG observations were used to train PLM and LMM approaches, and 456 patient records with 1244 TUG observations were used to test the predictions. The approaches performed similarly in terms of mean squared error and bias, but the PLM approach provided more accurate and precise estimates of prediction uncertainty. DISCUSSION AND CONCLUSION: Overall, the PLM approach more accurately and precisely predicted TUG recovery following knee arthroplasty. These results suggest PLM predictions may be more clinically useful for monitoring recovery and personalizing care following knee arthroplasty. However, clinicians and organizations seeking to use predictions in practice should consider additional factors (eg, resource requirements) when selecting a prediction approach.

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.

"This is not negotiable. You need to do this ": A directed content analysis of decision making in rehabilitation after knee arthroplasty.

PURPOSE: To understand patients' and physical therapists' perspectives related to decision making during outpatient rehabilitation after total knee arthroplasty (TKA), and to describe potential barriers and opportunities for shared decision making (SDM) in this setting. METHODS: A qualitative study examined the beliefs, thoughts, and experiences of patients and physical therapists regarding decision making in outpatient rehabilitation after TKA. Semi-structured interviews were conducted and analysed using directed content analysis. RESULTS: Thirty-five participants were interviewed (20 patients, 15 physical therapists). Three main themes emerged from the data: (1) there is variability among physical therapists in how patients are involved in care decisions, (2) several features of the outpatient care paradigm are not supportive of SDM, and (3) preoperative patient-clinician interactions may facilitate SDM in postoperative rehabilitation, but these interactions are not typically utilized. CONCLUSION: Physical therapists described using decision-making strategies with varying levels of patient involvement. Both patients and physical therapists described barriers to routine use of SDM in the outpatient setting. Several actionable strategies for overcoming these barriers were identified for providers and organizations seeking to consistently use SDM in outpatient TKA rehabilitation.

Examination of exclusion criteria in total knee arthroplasty rehabilitation trials: influence on the application of evidence in day-to-day practice.

OBJECTIVE: Total knee arthroplasty (TKA) rehabilitation trials use exclusion criteria, which may limit their generalizability in practice. We investigated whether patients seen in routine practice who meet common exclusion criteria recover differently from TKA compared to research-eligible patients. We hypothesized that research-ineligible patients would demonstrate poorer average postoperative function and slower rate of functional recovery compared to research-eligible patients. METHODS: Patient characteristics and exclusion criteria were extracted and summarized from trials included in the three most recent systematic reviews of TKA rehabilitation. Trial participant characteristics were compared to a clinical dataset of patient outcomes collected in routine TKA rehabilitation. Where possible, individual exclusion criterion from the trials were applied to the clinical dataset to determine "eligible" and "ineligible" groups for research participation. Postoperative functional outcomes including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Timed Up and Go (TUG) were compared between "eligible" and "ineligible" groups using mixed effects models. RESULTS: 2,528 participants from 27 trials were compared to 474 patients from the clinical dataset. Research participants were older, with lower Body Mass Index than patients in the clinical dataset. Many patients in the clinical dataset would be "ineligible" for research participation based upon common exclusion criteria from the trials. Differences were observed in average postoperative functioning between some "eligible" and "ineligible" groups in the clinical dataset. However, no differences were observed in functional recovery rate between groups, except for patients with diabetes whose TUG recovered more slowly than their "eligible" counterparts. CONCLUSIONS: Many patients in the clinical dataset were "ineligible" for research participation based upon common TKA rehabilitation trial exclusion criteria. However, the postoperative recovery rate did not differ between "eligible" and "ineligible" groups based on individual exclusion criterion-except for individuals with diabetes. This suggests that both clinical and research populations may recover similarly from TKA.

How New Technology Is Improving Physical Therapy.

PURPOSE OF REVIEW: As rehabilitation patient volume across the age spectrum increases and reimbursement rates decrease, clinicians are forced to produce favorable outcomes with limited resources and time. The purpose of this review is to highlight new technologies being utilized to improve standardization and outcomes for patients rehabilitating orthopedic injuries ranging from sports medicine to trauma to joint arthroplasty. RECENT FINDINGS: A proliferation of new technologies in rehabilitation has recently occurred with the hope of improved outcomes, better patient compliance and safety, and return to athletic performance. These include technologies applied directly to the patient such as exoskeletons and instrumented insoles to extrinsic applications such as biofeedback and personalized reference charts. Well-structured randomized trials are ongoing centered around the efficacy and safety of these new technologies to help guide clinical necessity and appropriate application. We present a range of new technologies that may assist a diverse population of orthopedic conditions. Many of these interventions are already supported by level 1 evidence and appear safe and feasible for most clinical settings.