Introduction Achilles tendon ruptures affect 15 (women) to 55 (men) per 100,000 people each year, and controversy continues to exist regarding optimal treatment and rehabilitation protocols. The objective of this study was to investigate the temporal effects of surgical repair and immobilization/activity (IM/ACT) on Achilles healing and limb function following complete transection in rodents. Methods Injured tendons (n=128) were repaired or left non-repaired, and animals groups immobilized in plantarflexion for 1, 3, or 6 weeks that later resumed cage and treadmill activity for 5, 3, or 0 weeks (IM1/ACT5, IM3/ACT3, IM6/ACT0). Animals were euthanized after 1- or 6-weeks post-injury. Results At 6-weeks post injury, IM1/ACT5 groups had increased range of motion and decreased ankle joint toe stiffness compared to IM3/ACT3 groups. IM6/ACT0 had decreased tendon cross sectional area, but increased tendon echogenicity and collagen alignment. Surgical treatment dramatically decreased fatigue cycles to failure in repaired tendons from earlier IM1/ACT5 groups. Normalized comparisons between 6- and 1-week post-injury data demonstrated that changes in healing tendon properties (area, alignment, and echogenicity) were maximized by IM1/ACT5 compared to IM6/ACT0. Discussion/Conclusion This study demonstrates how the temporal post-injury healing response of rodent Achilles tendons depends on both surgical treatment and the timing of IM/ACT.

Rotator cuff tears are common musculoskeletal injuries often requiring surgical intervention with high failure rates. Currently, pulsed electromagnetic fields (PEMFs) are used for treatment of long-bone fracture and lumbar and cervical spine fusion surgery. No studies have investigated PEMF in healing soft tissue. Therefore, we investigated the effect of PEMF on rotator cuff healing using a rat rotator cuff repair model. We hypothesized that PEMF exposure following rotator cuff repair would improve tendon mechanical properties, tissue morphology, and alter in vivo joint function. 70 adult male Sprague-Dawley rats were assigned to three groups: bilateral repair with PEMF (n=30), bilateral repair followed by cage activity (n=30), uninjured control with cage activity (n=10). Rats in the surgical groups were sacrificed at 4, 8, and 16 weeks. Control group was sacrificed at 8 weeks. Passive joint mechanics and gait analysis were assessed over time. Biomechanical analysis and µCT was performed on left shoulders; histological analysis on right shoulders. Results indicate no differences in passive joint mechanics and ambulation. At 4 weeks the PEMF group had decreased cross-sectional area and increased modulus and maximum stress. At 8 weeks the PEMF group had increased modulus and more rounded cells in the midsubstance. At 16 weeks the PEMF group had improved bone quality. Therefore, results indicate that PEMF improves early tendon healing and does not alter joint function in a rat rotator cuff repair model. Statement of Clinical Significance PEMF exposure following rotator cuff repair improves early tendon healing.

Rotator cuff tendon tears are one of the most common shoulder pathologies, especially in the aging population. Due to a poor healing response and degenerative changes associated with aging, rotator cuff repair failure remains common. Although cell-based therapies to augment rotator cuff repair appear promising, it is unknown whether the success of such a therapy is age-dependent. We hypothesized that autologous cell therapy would improve tendon-to-bone healing across age groups, with autologous juvenile cells realizing the greatest benefit. In this study, juvenile, adult, and aged rats underwent bilateral supraspinatus tendon repair with augmentation of one shoulder with autologous tendon-derived cell-seeded polycaprolactone scaffolds. At 8 weeks, shoulders treated with cells in both juvenile and aged animals exhibited increased cellularity, increased collagen organization, and improved mechanical properties. No changes between treated and control limbs were seen in adult rats. These findings suggest that cell delivery during supraspinatus repair initiates earlier matrix remodeling in juvenile and aged animals. This may be due to the relative “equilibrium” of adult tendon tissue with regards to catabolic and anabolic processes, contrasted with actively growing juvenile tendons and degenerative aged tendons. This study demonstrates the potential for autologous cell-seeded scaffolds to improve repairs in both the juvenile and aged population.

PurposeBody mass index (BMI) is often used to predict surgical difficulty in patients receiving total knee arthroplasty (TKA); however, BMI neglects variation in the central versus peripheral distribution of adipose tissue. We sought to examine whether anthropometric factors, rather than BMI alone, may serve as a more effective indication of surgical difficulty in TKA.Materials and MethodsWe prospectively enrolled 67 patients undergoing primary TKA. Correlation coefficients were used to evaluate the associations of tourniquet time, a surrogate of surgical difficulty, with BMI, pre- and intraoperative anthropometric measurements, and radiographic knee alignment. Similarly, Knee Injury and Osteoarthritis Outcome Score (KOOS) was compared to BMI.ResultsTourniquet time was significantly associated with preoperative inferior knee circumference (p=0.025) and ankle circumference (p=0.003) as well as the intraoperative depth of incision at the quadriceps (p=0.014). BMI was not significantly associated with tourniquet time or any of the radiographic parameters or KOOS scores.ConclusionsInferior knee circumference, ankle circumference, and depth of incision at the quadriceps (measures of peripheral obesity) are likely better predictors of surgical difficulty than BMI. Further study of alternative surgical indicators should investigate patients that may be deterred from TKA for high BMI, despite relatively low peripheral obesity.

Background: Geriatric hip fracture is a common condition, and there are many open questions regarding patient management. Among the various types of medical evidence, the prospective randomized controlled trial (RCT) is considered the best. Our primary hypothesis was that small sample size would be seen frequently among RCTs involving geriatric patients with hip fracture. A related hypothesis was that studies from the United States would have particularly large deficits in sample size. Therefore, we asked the following research questions: (1) What is the mean sample size of RCTs involving geriatric patients with hip fracture? (2) How do sample sizes for studies from the U.S. differ from those performed elsewhere? Methods: Following the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, a systematic review of hip fracture RCTs was conducted. The Embase and MEDLINE databases were searched. Additional data included the country of origin, the power of the study, and whether sample size calculations were performed. One hundred and forty-seven RCTs were identified. Results: The mean sample size of the 147 RCTs was 134.9. The mean sample size for the 7 American trials was 110.3, and the mean sample size for all trials conducted outside of the United States was 136.1. A sample size that was sufficient to ensure 80% power was used in only 31.3% of the RCTs. Conclusions: RCTs for hip fracture are small and underpowered. Moreover, <5% of the RCT studies have been conducted in the U.S., and they were smaller than those conducted elsewhere. The shortage of American trials may be a feature of the dispersion of geriatric hip fracture care across many hospitals in the United States. If so, better clinical research might require more centralized care (e.g., in specialized geriatric hip fracture centers) or greater collaboration among the many hospitals that provide care.