Advanced Age Diminishes Tendon-to-Bone Healing in a Rat Model of Rotator Cuff Repair

Abstract

BACKGROUND:Advanced patient age is associated with recurrent tearing and failure ofrotator cuff repairs clinically; however, basic science studies have not evaluated the influence of aging on tendon-to-bone healing after rotator cuff repair in an animal model.Hypothesis/ PURPOSE:This study examined the effect of aging on tendon-to-bone healing in an established rat model of rotator cuff repair using the aged animal colony from the National Institute on Aging of the National Institutes of Health. The authors hypothesized that normal aging decreases biomechanical strength and histologic organization at the tendon-to-bone junction after acute repair. STUDY DESIGN:Controlled laboratory study. METHODS:In 56 F344xBN rats, 28 old and 28 young (24 and 8 months of age, respectively), the supraspinatus tendon was transected and repaired. At 2 or 8 weeks after surgery, shoulder specimens underwent biomechanical testing to compare load-to-failure and load-relaxation response between age groups. Histologic sections of the tendon-to-bone interface were assessed with hematoxylin and eosin staining, and collagen fiber organization was assessed by semiquantitative analysis of picrosirius red birefringence under polarized light. RESULTS:Peak failure load was similar between young and old animals at 2 weeks after repair (31% vs 26% of age-matched uninjured controls, respectively; P > .05) but significantly higher in young animals compared with old animals 8 weeks after repair (86% vs 65% of age-matched uninjured controls, respectively; P < .01). Eight weeks after repair, fibroblasts appeared more organized and uniformly aligned in young animals on hematoxylin and eosin slides compared with old animals. Collagen birefringence analysis of the tendon-to-bone junction demonstrated that young animals had increased collagen fiber organization and similar histologic structure compared with age-matched controls (53.7 ± 2.4 gray scales; P > .05). In contrast, old animals had decreased collagen fiber organization and altered structure compared with age-matched controls (49.8 ± 3.1 gray scales; P < .01).Discussion:In a rat model of aging, old animals demonstrated diminished tendon-to-bone healing after rotator cuff injury and repair. Old animals had significantly decreased failure strength and collagen fiber organization at the tendon-to-bone junction compared with young animals. This study implies that animal age may need to be considered in future studies of rotator cuff repair in animal models. CLINICAL RELEVANCE:With increasing age and activity level of the population, the incidence of rotator cuff tears is predicted to rise. Despite advances in rotator cuff repair technique, the retear rate remains specifically high in elderly patients. The findings of this research suggest that aging negatively influences tendon-to-bone healing after rotator cuff repair in a validated animal model.

KEYWORDS:

aging, biomechanics, elderly, quasi-linear viscoelastic, rehabilitation, rotator cufftear, shoulder

PMID:

 

24500915

 

[PubMed - as supplied by publisher]

Safety and efficacy of laparoscopic adjustable gastric banding in patients aged seventy and older

Abstract

BACKGROUND:

Life expectancy is increasing, with more elderly people categorized as obese. The objective of this study was to assess the effects of laparoscopic adjustable gastric banding (LAGB) on patients aged ≥70 years.

METHODS:

This was a retrospective analysis of patients aged ≥70 years who underwent LAGB at our university hospital between 2003 and 2011. The data included age, weight, body mass index (BMI), and percentage excess weight loss (%EWL) obtained before and after gastric banding. Operative data, length of stay, postoperative complications, and resolution of co-morbid conditions were also analyzed.

RESULTS:

Fifty-five patients aged ≥70 years (mean 73 years) underwent gastric banding between 2003 and 2012. Mean preoperative weight and BMI were 123 kilograms and 45 kg/m², respectively. On average, each patient had 4 co-morbidities preoperatively, with hypertension (n = 49; 86%), dyslipidemia (n = 40; 70%), and sleep apnea (n = 31; 54%) being the most common. Mean operating room (OR) time was 49 minutes, with all patients discharged within 24 hours. There was 1 death at 4 years from myocardial infarction, no intensive care unit admissions, and no 30-day readmissions. Mean %EWL at 1, 2, 3, 4, and 5 years was 36 (±12.7), 40 (±16.4), 42 (±19.2), 41 (±17.1), 50 (±14.9), and 48 (±22.6), respectively. Follow-up rates ranged from 55/55 (100%) at 6 months to 7/9 (78%) of eligible patients at 5 years and 2/2 (100%) at 8 years. Complications included 1 band slip at year 5, 1 band removed for intolerance, and 1 port site hernia. The resolution of hypertension, dyslipidemia, sleep apnea, lower back pain, and non-insulin-dependent diabetes was 27%, 28%, 35%, 31%, and 35%, respectively.

CONCLUSIONS:

LAGB as a primary treatment for obesity in carefully selected patients aged ≥70 can be well tolerated and effective with moderate resolution of co-morbid conditions and few complications.

Copyright © 2014 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

KEYWORDS:

Bariatric, Elderly, Gastric banding, Obesity, Safety