Background:

Being overweight or obese is associated with poor outcomes and an increased risk of failure after rotator cuff (RC) surgery. However, the effect of obesity on enthesis healing has not been well characterized.

Hypotheses:

Diet-induced obesity (DIO) would result in inferior enthesis healing in a rat model of RC repair, and a dietary intervention in the perioperative period would improve enthesis healing.

Study Design:

Controlled laboratory study.

Methods:

Male Sprague-Dawley rats were divided into 3 weight-matched groups (n = 26 per group): control diet (CD), high-fat diet (HFD), or HFD until surgery and then CD thereafter (HF-CD). After 12 weeks, the left supraspinatus tendon was detached, followed by immediate repair. Animals were sacrificed, and RCs were harvested at 2 and 12 weeks after surgery for biomechanical and histological evaluations. Metabolic end points were assessed using dual-energy X-ray absorptiometry and plasma analyses.

Results:

DIO was established in the HFD and HF-CD groups before surgery and subsequently reversed in the HF-CD group after surgery. At 12 weeks after surgery, the body fat percentage (P = .0021) and plasma leptin concentration (P = .0025) were higher in the HFD group compared with the CD group. Histologically, the appearance of the repaired entheses was poorer in both the HFD and HF-CD groups compared with the CD group at 12 weeks after surgery, with semiquantitative scores of 6.20 (P = .0078), 4.98 (P = .0003), and 8.68 of 15, respectively. The repaired entheses in the HF-CD group had a significantly lower load to failure (P = .0278) at 12 weeks after surgery compared with the CD group, while the load to failure in the HFD group was low but not significantly different (P = .0960). There were no differences in the biomechanical and histological results between the groups at 2 weeks after surgery. Body mass at the time of surgery, plasma leptin concentration, and body fat percentage were negatively correlated with histology scores and plasma leptin concentration was correlated with load to failure at 12 weeks after surgery.

Conclusion:

DIO impaired enthesis healing in this rat RC repair model, with inferior biomechanical and histological outcomes. Restoring a normal weight with dietary changes after surgery did not improve healing outcomes.

Clinical Relevance:

Obesity is a potentially modifiable factor that impairs RC healing and increases the risk of failure after surgery. Exploring interventions that improve the metabolic state of obese patients and counseling patients appropriately about their modest expectations after repair should be considered.

中文翻译：

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肥胖会损害大鼠模型中肩袖修复后的肌腱愈合

背景：

超重或肥胖与肩袖 (RC) 手术后不良结果和失败风险增加有关。然而，肥胖对附着点愈合的影响尚未得到很好的表征。

假设：

饮食诱导的肥胖 (DIO) 会导致 RC 修复大鼠模型中的附着点愈合不良，并且围手术期的饮食干预将改善附着点愈合。

学习规划：

受控实验室研究。

方法：

雄性 Sprague-Dawley 大鼠分为 3 个体重匹配组（每组 n = 26）：控制饮食（CD）、高脂饮食（HFD）或 HFD，直到手术，然后是 CD（HF-CD）。12周后，左侧冈上肌腱脱落，立即修复。处死动物，并在手术后 2 周和 12 周收获 RC，用于生物力学和组织学评估。使用双能 X 射线吸收测定法和血浆分析评估代谢终点。

结果：

DIO 在术前在 HFD 和 HF-CD 组中建立，随后在术后在 HF-CD 组中逆转。术后 12 周，HFD 组的体脂百分比 ( P = .0021) 和血浆瘦素浓度 ( P = .0025) 高于 CD 组。组织学上，术后 12 周，HFD 组和 HF-CD 组修复肌腱的外观均较 CD 组更差，半定量评分分别为 6.20（P = .0078）、4.98（P = .0003 ）、和 15 个中的 8.68 个，分别。HF-CD组修复的肌腱断裂负荷显着降低（P= .0278) 术后 12 周与 CD 组相比，HFD 组的失败负荷较低但无显着差异 ( P = .0960)。术后 2 周各组的生物力学和组织学结果无差异。手术时的体重、血浆瘦素浓度和体脂百分比与组织学评分呈负相关，血浆瘦素浓度与手术后 12 周时的负荷负荷相关。

结论：

在这种大鼠 RC 修复模型中，DIO 损害了附着点愈合，生物力学和组织学结果较差。手术后通过改变饮食来恢复正常体重并不能改善愈合结果。

临床相关性：

肥胖是一个潜在的可改变因素，它会损害 RC 愈合并增加手术后失败的风险。应考虑探索改善肥胖患者代谢状态的干预措施，并适当告知患者修复后的适度期望。