Programmable mechanical stimulation influences tendon homeostasis in a bioreactor system.

Identification of functional programmable mechanical stimulation (PMS) on tendon not only provides the insight of the tendon homeostasis under physical/pathological condition, but also guides a better engineering strategy for tendon regeneration. The aims of the study are to design a bioreactor system with PMS to mimic the in vivo loading conditions, and to define the impact of different cyclic tensile strain on tendon. Rabbit Achilles tendons were loaded in the bioreactor with/without cyclic tensile loading (0.25 Hz for 8 h/day, 0-9% for 6 days). Tendons without loading lost its structure integrity as evidenced by disorientated collagen fiber, increased type III collagen expression, and increased cell apoptosis. Tendons with 3% of cyclic tensile loading had moderate matrix deterioration and elevated expression levels of MMP-1, 3, and 12, whilst exceeded loading regime of 9% caused massive rupture of collagen bundle. However, 6% of cyclic tensile strain was able to maintain the structural integrity and cellular function. Our data indicated that an optimal PMS is required to maintain the tendon homeostasis and there is only a narrow range of tensile strain that can induce the anabolic action. The clinical impact of this study is that optimized eccentric training program is needed to achieve maximum beneficial effects on chronic tendinopathy management.

Incidence and Associated Risk Factors for Falls in Older Adults After Elective Total Knee Replacement Surgery: A Prospective Cohort Study.

OBJECTIVE: The aim of the study was to determine the incidence and associated risk factors for falls in older adults in the 12 mos after elective, primary total knee replacement surgery. DESIGN: A prospective observational cohort of older adults undergoing total knee replacement were followed. Baseline measurements included risk factors of history of falls, using a gait aid and number of medications. Falls data were recorded after discharge for 12 mos alongside patient reported outcomes (Oxford Knee Score). Analyses used logistic and negative binomial regression modeling. RESULTS: There were 267 participants (mean age = 70 [6.7] yrs) enrolled. Participants who fell (n = 102 [40.6%]) reported 200 falls in the 12 mos after surgery. The incidence of falls was 2.4 falls per 1000 patient days in the 12 mos after surgery, with the highest incidence (2.6 falls per 1000 patient days) in month 1. Risk factors for falling were a history of falls (adjusted odds ratio = 2.41, 95% confidence interval = 1.35-4.31) and number of central nervous system acting medications taken before surgery (adjusted odds ratio = 1.66, 95% confidence interval = 1.25-2.21). Using a walking aid at baseline was associated with falls after discharge (adjusted incident rate ratio = 2.38, 95% confidence interval = 1.57-3.60). CONCLUSIONS: Older adults experience a high incidence of falls after elective total knee replacement. Further research that investigates falls prevention after total knee replacement is required.

Functional outcome of matrix-associated autologous chondrocyte implantation in the ankle.

BACKGROUND: The technique of Matrix-associated autologous chondrocyte implantation (MACI) is well established with satisfactory outcomes up to 5 years in the knee. Fewer series describe the outcomes of this technique in the ankle. We present the functional outcomes of the technique for a single surgeon series in a general hospital setting. MATERIALS AND METHODS: Twenty-seven patients, mean age 41, were reviewed at 3.7 (range, 1 to 5) years. Patients were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot scale, Tegener activity score and University of California lower extremity activity scale. MRI findings were also reviewed. RESULTS: While most patients report a significant improvement in symptoms with full return to activities of daily living, 36% of those under 40 and 78% of those over 40 reported restricted recreational activity. Of the patients under 40 years of age, 86% were able to run compared with 23% of those over 40. Of patients over 40, 64% continued to have moderate or severe pain. CONCLUSION: Careful preoperative counseling is required for patients of all ages regarding likely outcomes. In patients over 40, the procedure is unlikely to give good pain relief and alternative options should be considered.

Incidence and Associated Risk Factors for Falls in Older Adults Postdischarge Who Undergo Elective Total Hip Replacement Surgery-A Prospective Cohort Study.

BACKGROUND: Hip replacement surgery improves health-related quality of life; however, it has been suggested that falls rates increase after hospital discharge. The aim of the study was to determine the incidence and associated risk factors for falls in older adults in the 12 months after undergoing elective total hip replacement surgery. METHODS: A prospective observational cohort study was conducted. Participants were adults aged 60 years or older who underwent primary elective total hip replacement surgery in a private tertiary hospital in Perth, Australia. Baseline data collected immediately prior to discharge included use of walking aids, medications, and functional level of independence (using Katz and Lawton scales). Falls data were collected for 12 months using calendars and monthly phone calls. Data were analyzed using logistic and negative binomial regression modeling. RESULTS: Participants' ([n = 167], 54.4% female) mean age was 71.2 (±6.9) years. There were 51 (31%) participants who used a walking aid prior to surgery. There were 140 falls reported over 12 months by 67 (42%) participants, of which 90 (64.3%) were injurious (n = 9 fractures). The fall rate was 2.6 per 1000 patient-days. Age (adjusted odds ratio 1.10, 95% confidence interval 1.01-1.20) and hospital length of stay (adjusted odds ratio 1.24, 95% confidence interval 1.00-1.54).were significantly associated with sustaining multiple falls. CONCLUSIONS: More than 40% of older adults fell in the 12 months after elective hip replacement surgery although the cohort had low fall risk prior to surgery. Rehabilitation after hip replacement surgery should consider fall prevention.

Incidence, risk factors and the healthcare cost of falls postdischarge after elective total hip and total knee replacement surgery: protocol for a prospective observational cohort study.

INTRODUCTION: The number of major joint replacement procedures continues to increase in Australia. The primary aim of this study is to determine the incidence of falls in the first 12 months after discharge from hospital in a cohort of older patients who undergo elective total hip or total knee replacement. METHODS AND ANALYSES: A prospective longitudinal observational cohort study starting in July 2015, enrolling patients aged ≥60 years who are admitted for elective major joint replacement (n=267 total hip replacement, n=267 total knee replacement) and are to be discharged to the community. Participants are followed up for 12 months after hospital discharge. The primary outcome measure is the rate of falls per thousand patient-days. Falls data will be collected by 2 methods: issuing a falls diary to each participant and telephoning participants monthly after discharge. Secondary outcomes include the rate of injurious falls and health-related quality of life. Patient-rated outcomes will be measured using the Oxford Hip or Oxford Knee score. Generalised linear mixed modelling will be used to examine the falls outcomes in the 12 months after discharge and to examine patient and clinical characteristics predictive of falls. An economic evaluation will be conducted to describe the nature of healthcare costs in the first 12 months after elective joint replacement and estimate costs directly attributable to fall events. ETHICS AND DISSEMINATION: The results will be disseminated through local site networks and will inform future services to support older people undergoing hip or knee joint replacement and also through peer-reviewed publications and medical conferences. This study has been approved by The University of Notre Dame Australia and local hospital human research ethics committees. TRIAL REGISTRATION NUMBER: ACTRN12615000653561; Pre-results.