Quadriceps femoris muscle weakness has long been associated with disuse atrophy in symptomatic knee osteoarthritis but more recently implicated in the aetiology of this condition. The purpose of this study was to assess the benefits of two interventions aimed at increasing quadriceps strength in subjects with moderate to severe knee osteoarthritis.

Twenty-eight patients, aged fifty-five to seventy-five, were recruited and randomised to either a six-week home resistance-training exercise program or a six-week neuromuscular electrical stimulation (NMES) program. Eleven patients matched for age, gender and osteoarthritis severity formed a control group, receiving standard care. The resistance-training group performed six exercises three times per week, while the NMES group used the garment stimulator for twenty minutes five times per week Outcome measures included isometric and isokinetic quadriceps strength, functional capacity, quadriceps cross-sectional area, and validated health survey scores. These measures were assessed at baseline, post-intervention and at 6-weeks post-intervention.

Both intervention groups showed significant improvements in all functional tests, in the global health survey, and in quadriceps cross-sectional area immediately post-intervention. An increase in isokinetic strength was seen in the exercise group only. With the exception of isokinetic strength, all benefits were maintained six weeks post-intervention.

Both a six-week home resistance-training program and a six-week NMES program produce significant improvements in functional performance as well as physical and mental health for patients with moderate to severe knee osteoarthritis. Home-based NMES is an acceptable alternative to physical therapy, and is especially appropriate for patients who have difficulty complying with an exercise program.

Background: Knee osteoarthritis is responsible for more chronic disability than any other medical condition. Quadriceps femoris muscle weakness has long been associated with disuse atrophy in symptomatic knee osteoarthritis but more recently implicated in the aetiology of this condition. The purpose of this study was to assess the benefits of two interventions aimed at increasing quadriceps strength in subjects with moderate to severe knee osteoarthritis.

Methods: Twenty-eight patients, aged 55–75 years, diagnosed with moderate to severe knee osteoarthritis were recruited and randomised to either a six-week home resistance-training exercise program or a six-week home neuromuscular electrical stimulation (NMES) program. An additional eleven patients matched for age, gender and osteoarthritis severity formed a control group, receiving standard care. The resistance-training group performed six exercises three times per week, while the NMES group used the garment stimulator at the maximum intensity tolerated for twenty minutes five times per week. Outcome measures included isometric and isokinetic quadriceps strength, functional capacity (25m walk test, chair rise test, stair climb test), Western Ontario and McMaster Osteoarthritis Index (WOMAC) and Short Form 36 (SF-36) health surveys. These measures were assessed at baseline, pre-intervention (after familiarisation), post-intervention and at 6-weeks post-intervention. Additionally, quadriceps cross-sectional area (via MRI) and muscle atrophy/hypertrophy gene expression (via vastus lateralis biopsy) were assessed pre- and post-intervention.

Results: Both intervention groups showed significant improvements in all functional tests (e.g. in the stair test, a 22% improvement in the exercise group versus 17% for the NMES group), in the SF36 health survey (25% & 22% respectively), and in quadriceps cross-sectional area (4.3% & 5.4%) immediately post-intervention. An increase in isokinetic strength was seen in the exercise group only (11%). WOMAC score improved only for the NMES group (19%). With the exception of isokinetic strength, all benefits were maintained six weeks post-intervention.

Conclusions: Both a six-week home resistance-training program and a six-week home NMES program produced significant improvements in functional performance as well as physical and mental health for patients with moderate to severe knee osteoarthritis. Home-based NMES is an acceptable alternative to physical therapy for patients with knee osteoarthritis, and is especially appropriate for patients who have difficulty complying with an exercise program.

Introduction: Quadriceps femoris (QF) atrophy has been associated with the development of knee OA and is a major cause of functional limitations in affected individuals. TKA reliably reduces pain but improvements in function are less predictable and deficits may persist for up to 2 years post-operatively. Patients undergoing elective surgery are routinely optimized medically but we hypothesized that pre-operative strength and fitness improvements would also enhance outcome.

Objectives: To determine the effect of a 6 week lower limb strengthening programme on post-operative QF strength and CSA, pain and functional scores.

To determine changes in Myosin Heavy Chain (MHC) isoform, hypertrophy marker IGF-1 and atrophy markers MuRF-1 and MAFbx.

Methods: 20 volunteers currently awaiting TKA were randomly assigned to a control [C] or intervention [I] group. [I] completed a 6 week home based, supervised exercise programme. Post-operatively all patients completed a standard inpatient physiotherapy routine.

Assessments were completed at baseline (T=0), T=6 weeks (just prior to operation) and 3 months post-operatively (T=18 weeks). Assessments included isokinetic dynamometry; MRI QF CSA and American Knee Society scores. A percutaneous muscle biopsy of the vastus lateralis muscle was also performed at T=0 and T=6 under local anaesthesia.

Results: At baseline there were no significant differences in parameters between groups. At T=18, [I] showed an 86% difference in QF peak torque above controls (P=0.003). CSA also improved by 6% versus a drop of 2.5% in [C] (P=0.041). Both groups showed improvements in Knee society function scores but [I] improved by 13 points more than [C] (P=0.044).

MHC IIa mRNA expression increased by 40% whilst IIx decreased by 60% representing a shift to a less fatigable fibre type (P=0.05 and 0.028 respectively). IGF-1, MuRF-1 and MAFbx mRNA levels did not change significantly in either group.

Conclusion: To our knowledge we have documented for the first time post-operative benefits by using a pre-operative training programme in TKA. This was manifest by continued rise in quadriceps peak torque, CSA and improved Knee society functional scores. We have also demonstrated the preservation of muscle plasticity in knee OA and suggest that factors other than known hypertrophy and atrophy pathways may be responsible.

Introduction: After total knee arthroplasty (TKA) patients develop marked asymmetrical quadriceps femoris (QFM) weakness due to neurological activation deficits and muscle atrophy; this is associated with a slow (type I) to fast (type II) shift in myosin heavy chain (MHC) expression. Preoperative resistance training (prehabilitation) has been shown to improve strength and function after TKA however is considered costly and labour intensive. Neuromuscular electrical stimulation (NMES) offers the potential for unsupervised training, although its role in prehabilitation has not been investigated.

Aims: Determine changes in myosin heavy chain (MHC) mRNA expression following preoperative NMES.

Evaluate the ability of NMES prehabilitation to improve strength and functional recovery post-TKA.

Methods: Randomised control efficacy study applying NMES to the affected QFM for 20 min, 5 days/week, for 8 weeks pre-TKA. Isometric QFM strength was determined dynametrically and muscle cross-sectional area (CSA) calculated from MRI axial images. Function was assessed with a walk test, stair-climb test, and chair-rise test. Real-time PCR analysed MHC mRNA expression. All evaluations were performed at baseline and preoperatively with strength, CSA and function also tested at 6 and 12 weeks post-TKA.

Results: Patients scheduled for TKA were recruited and randomised into control (n=9) or NMES (n=5) groups. Only the NMES group increased strength (27.8%; p=0.05) and CSA (7.4%; p=0.013) preoperatively. MHC type II mRNA decreased by 42% (p=0.078) indicating a fast to slow fibre shift. Function also improved in the NMES group (stair climb [p=0.006]; chair rise [p=0.018]). While all patients deteriorated after surgery, only the NMES group had notable strength gain from 6 to 12 weeks (53%; p=0.011) with associated functional recovery (stair-climb, p=0.017; chair-rise, p=0.01; walking speed, p=0.014). There were differences seen between the groups at 3 months post-TKA: stair climb (61.6%, p=0.04) and chair rise (28.4%, p=0.013). There was greater muscle atrophy seen in the controls than the NMES group post-TKA when compared to baseline (12.1% [p=0.034] versus 3.7% [ns]).

Conclusions: This study has shown that 8 weeks preoperative quadriceps strengthening using home-based NMES can safely and effectively attenuate the extent and duration of QFM weakness and atrophy after primary TKA. This translates into significantly faster functional recovery thereby expediting a return to normal activities.

Introduction: Quadriceps femoris muscle (QFM) weakness has been associated with the development and progression of knee osteoarthritis, primarily due to arthrogenic muscle inhibition. Neuromuscular electrical stimulation (NMES) devices cause muscle contraction by circumventing these neural inhibitory feedback pathways. While it has been proposed this occurs in a reversed pattern of muscle fibre recruitment, the molecular mechanisms have not been clearly elucidated.

Methods: This randomised control efficacy study applied NMES to the affected QFM for 20 min, 5 days a week, for 8 weeks. Strength was assessed dynometrically and function determined using validated measures (timed stair climb, chair rise and 25 metre walk tests). A quantitative polymerase chain reaction (PCR) method measured quantities of types I, IIa, and IIx myosin heavy chain (MHC) mRNA of muscle specimens taken from vastus lateralis of the affected QFM. Expression of genetic markers associated with muscle wasting (MAFbx and MURF-1; E3 muscle specific ligases of the ubiquitin proteasome pathway) and muscle anabolic states (IGF-1) were also determined. Statistical analysis was performed using ANOVA’s and independent t-test’s where appropriate.

Results: Sixteen patients (10 women and 6 men) with radiologically severe knee OA were recruited and randomised into a control (n=6) or intervention (n=10) group. Groups were similar in terms of age (64.8 ± 11.0 vs. 64.6 ± 7.6; mean ± SD) and BMI (31.8 ± 6.1 vs.30.7 ± 2.9). There were significant improvements in function (stair climb [p< 0.01]; chair rise [p< 0.01]) and QFM strength (isokinetic [p< 0.01]; isometric [p< 0.01]) in the NMES group at week 8 compared to week 0. At the genetic level, IGF1 expression significantly increased two-fold in the NMES group (p< 0.05); Despite a 17% decrease in MAFbx expression, neither it nor MURF-1 changed significantly. MHC-I and MHC-IIa mRNA expression did not change in either group; MHC-IIx decreased by 42% in the NMES group only but was not statistically significant.

Conclusions: The use of an 8 week NMES program produces significant quadriceps strength gain with associated functional improvements in subjects with severe knee OA. Expression of muscle atrophy markers did not change significantly; however increased IGF-1 expression could potentially inhibit further muscle atrophy. Of the 3 MHC mRNA isoforms, only MHC-IIx demonstrated a change in response to NMES. These results would indicate NMES induces early quadriceps strength gain by a predominantly neurological adaptation.

Background: Quadriceps femoris muscle (QFM) weakness has been implicated in the development of knee osteoarthritis (OA) as well as predicting functional ability after TKA. Preoperative strengthening (prehabilitation) may be facilitated by applying neuromuscular electrical stimulation (NMES) to the affected QFM using a garment-based portable stimulator.

Methods: Single blind, randomised control efficacy study with NMES applied to the affected QFM for 20 min, 5 days a week, for 8 weeks pre-TKA. Isokinetic and isometric strength was assessed at baseline, week 2, week 5 and immediately pre-op. Function was assessed using a 25 metre timed walk test (TWT), timed stair-climb test (SCT), and timed chair-rise test (CRT) at baseline and pre-op.

Results: 13 patients (8 women and 5 men) scheduled for TKA for knee OA were recruited and randomised into a control (n=5) or intervention (n=8) group. Groups were similar in terms of age (65.5 ± 6.8 vs. 61.8 ± 9.0; mean ± SD) and BMI (29.7 ± 2.1 vs.33.2 ± 5.6). There was an improvement in SCT (p< 0.01) and CRT (p< 0.01) in the NMES group at week 8 compared to week 0. Isokinetic hamstring strength and isometric QFM strength increased significantly at weeks 2, 5 and 8 compared to baseline whereas isokinetic QFM strength only increased at week 5 (p< 0.05) and week 8 (p< 0.01) compared to baseline.

Conclusion: The use of a portable home-based NMES program for 8 weeks results in significant strength gains with associated improvements in function in patients scheduled for TKA for knee OA.