Functionally aligned total knee arthroplasty: A lateral flexion laxity up to 6 mm is safe!

PURPOSE: Loose flexion gaps are associated with poor functional outcomes and instability in total knee arthroplasty (TKA). The effect of a trapezoidal flexion gap in a functionally aligned TKA remains unknown. The aim of this study was to investigate the effect of a larger lateral flexion gap in a robotic-assisted (RA), functionally aligned (FA) and cruciate-retaining (CR) TKA on clinical outcomes. METHODS: Data from 527 TKA in 478 patients from 2018 to 2020 were collected. All patients underwent an RA (MAKO, Stryker), FA and CR TKA. Gap measurements were collected intraoperatively. Patient-reported outcome measures (PROMs), pain Visual analogue score (VAS) and range of motion were collected postoperatively. Patients were also asked about the ease of stair ascent and descent and kneeling on a 5-point scale. The minimum follow-up was 2 years. Patients were stratified into three groups based on lateral flexion laxity. RESULTS: At 2 years postoperatively, the group with a looser gap (3-6 mm) had higher mean PROMs when compared with the group with a gap of 2-3 mm. There were no differences detected in any other outcomes at 2 years. A total of 70.9% of patients in the group with a 3-6 mm gap reported being able to walk down a flight of stairs 'easily', compared with 56.7% in the 2-3 mm group and 54% in the <2 mm group (p = 0.04). CONCLUSION: The study shows that a loose lateral flexion gap in functionally aligned CR TKA does not adversely affect outcomes in the short term. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Twelve weeks of water-based circuit training exercise improves fitness, body fat and leg strength in people with stable coronary heart disease: a randomised trial.

QUESTION: In people with stable coronary heart disease, what are the effects of water-based circuit training exercise on aerobic capacity, strength and body composition? How do these effects compare with those of gym-based exercise? DESIGN: Parallel group, randomised controlled trial with concealed allocation and intention-to-treat analysis. PARTICIPANTS: Fifty-two participants with stable coronary heart disease. INTERVENTIONS: Twelve weeks of: three 1-hour sessions per week of moderate-intensity water-based circuit training exercise with alternating aerobic and resistance stations (WEX); three 1-hour sessions per week of moderate-intensity gym-based circuit training exercise (GEX); or continuing usual activities (control). OUTCOME MEASURES: Aerobic capacity (VO2peak), upper and lower limb one repetition maximum strength (biceps curl, latissimus dorsi pulldown, hamstring curl and leg press), anthropometry (weight, body mass index and girth) and dual energy x-ray absorptiometry. RESULTS: Forty-five participants completed the study (WEX n = 15, GEX n = 18, control n = 12). Both training groups significantly improved VO2peak compared with control: WEX by 2.5 ml/kg/min (95% CI 0.6 to 4.4) and GEX by 2.3 ml/kg/min (95% CI 0.6 to 4.0). WEX and GEX improved hamstring strength compared with control: WEX by 6.3 kg (95% CI 1.2 to 11.3) and GEX by 7.6 kg (95% CI 2.9 to 12.2). Compared with control, GEX increased leg press strength by 15.5 kg (95% CI 5.7 to 25.3), whereas the effect of WEX was less clear (MD 7.1 kg, 95% CI -3.5 to 17.7). Only GEX improved latissimus dorsi pulldown strength. Compared with control, total body fat was reduced with WEX (-1.1 kg, 95% CI -2.3 to 0.0) and GEX (-1.2 kg, 95% CI -2.3 to -0.1). There were negligible between-group differences in weight or waist circumference. CONCLUSION: WEX was well tolerated and improved aerobic capacity, leg strength and body fat to a similar degree as GEX in people with coronary heart disease. These findings suggest that WEX is an effective exercise training alternative to GEX for people with coronary heart disease. TRIAL REGISTRATION: ANZCTR12616000102471.

High-intensity interval training in patients with left ventricular assist devices: A pilot randomized controlled trial.

BACKGROUND: Left ventricular assist device (LVAD) implantation is an established treatment for patients with advanced heart failure. To date, studies evaluating the impact of aerobic training in patients with LVADs have focused on moderate-intensity exercise. METHODS: This pilot randomized controlled trial compared the effects of high-intensity interval training (HIIT) with those of moderate-intensity continuous training (MICT) on peak oxygen consumption (V̇O2 peak) in patients with LVADs. Secondary outcomes included 6-minute walk test distance, flow-mediated dilation, and anthropometry. Assessments were conducted at baseline and after 12 weeks of supervised training performed 3 times weekly. Participants were randomized to HIIT (4 sets of 4 minutes at 80%-90% V̇O2 reserve, alternating with 3 minutes at 50%-60% V̇O2 reserve) or MICT groups (28 minutes continuously at 50%-60% V̇O2 reserve). Within and between-group differences were analyzed using linear mixed models. Data are expressed as marginal means with 95% confidence intervals or as mean ± SD. RESULTS: A total of 21 participants were randomized (HIIT: age 57.7 ± 13.1 years; n = 11 and MICT: age 55.6 ± 14.2 years; n = 10) (mean ± SD). No major adverse events occurred in response to training in either group. HIIT significantly improved V̇O2 peak (15.6 [13.2-17.8] to 18.4 [16.0-20.8] ml/kg/min) (marginal mean [95% CI]) compared with MICT (16.2 [13.8-18.7] to 17.2 [14.6-19.7] ml/kg/min; p < 0.05 between groups). No significant group differences were detected in secondary outcomes. CONCLUSION: In patients with LVADs, HIIT was well tolerated and increased aerobic capacity more than MICT. These preliminary findings support the prescription of high-intensity exercise in clinically stable patients with LVADs but warrant validation in a larger sample and across a broader range of physiologic and clinical outcomes. CLINICAL TRIAL REGISTRATION: URL: https://www.anzctr.org.au, unique identifier: ACTRN12616001596493.

Physical Activity Is Higher in Patients with Left Ventricular Assist Device Compared with Chronic Heart Failure.

PURPOSE: Left ventricular assist devices (LVAD) are associated with an increased aerobic capacity in patients with chronic heart failure (CHF). However, studies evaluating the impact of LVAD implantation on physical activity (PA) are lacking. The aim of this study was to compare daily PA levels in participants with LVAD with well-matched CHF participants. METHODS: Sixteen participants with an LVAD (age, 59.1 ± 10.8 yr) were case-matched to 16 participants with advanced CHF (age, 58.3 ± 8.7 yr), who were listed or being considered for cardiac transplantation. Participants underwent a cardiopulmonary exercise test to determine peak oxygen consumption (V˙O2 peak). Physical activity was monitored continuously for seven consecutive days with an Actiheart monitor. RESULTS: V˙O2 peak in the CHF group (12.3 ± 3.5 mL·kg·min) was not significantly different to the LVAD group before LVAD implantation (10.4 ± 2.1 mL·kg·min), but was lower than in the LVAD group after implantation (15.8 ± 4.3 mL·kg·min; P < 0.05). Physical activity was higher in the LVAD (19.7 ± 6.4 kJ·kg·d) compared with the CHF group (11.6 ± 6.9 kJ·kg·d; P = 0.001). The LVAD participants spent more time performing moderate-intensity PA than their CHF counterparts (median, 26 min·d; interquartile range, 24-40 min·d vs median, 12 min·d; interquartile range, 9-16 min·d; P < 0.001). Physical activity was correlated with V˙O2 peak (r = 0.582; P = 0.001) across participants in the CHF and LVAD groups. CONCLUSIONS: Higher levels of PA were observed in participants with LVAD compared with patients with advanced CHF. This may be due to a higher V˙O2 peak, resulting in an improved capacity to perform activities of daily living with less symptoms.

Cerebral blood flow responses to exercise are enhanced in left ventricular assist device patients after an exercise rehabilitation program.

Cerebral blood flow during exercise is impaired in patients with heart failure implanted with left ventricular assist devices (LVADs). Our aim was to determine whether a 3-mo exercise training program could mitigate cerebrovascular dysfunction. Internal carotid artery (ICA) blood flow and intracranial middle (MCAv) and posterior cerebral (PCAv) artery velocities were measured continuously using Doppler ultrasound, alongside cardiorespiratory measures at rest and in response to an incremental cycle ergometer exercise protocol in 12 LVAD participants (5 female, 53.6 ± 11.8 yr; 84.2 ± 15.7 kg; 1.73 ± 0.08) pre- (PreTR) and post- (PostTR) completion of a 3-mo supervised exercise rehabilitation program. At rest, only PCAv was different PostTR (38.1 ± 10.4 cm/s) compared with PreTR (43.0 ± 10.8 cm/s; P < 0.05). PreTR, the reduction in PCAv observed from rest to exercise (5.2 ± 1.8%) was mitigated PostTR (P < 0.001). Similarly, exercise training enhanced ICA flow during submaximal exercise (~8.6 ± 13.7%), resulting in increased ICA flow PostTR compared with a reduced flow PreTR (P < 0.001). Although both end-tidal partial pressure of carbon dioxide and mean arterial pressure responses during incremental exercise were greater PostTR than PreTR, only the improved PETCO2 was related to the improved ICA flow (R2 = 0.14; P < 0.05). Our findings suggest that short-term exercise training improves cerebrovascular function during exercise in patients with LVADs. This finding should encourage future studies investigating long-term exercise training and cerebral and peripheral vascular adaptation.NEW & NOTEWORTHY Left ventricular assist devices, now used as destination therapy in end-stage heart failure, enable patients to undertake rehabilitative exercise training. We show, for the first time in humans, that training improves cerebrovascular function during exercise in patients with left ventricular assist devices. This finding may have implications for cerebrovascular health in patients with heart failure.