Delayed Early Passive Motion Is Harmless to Shoulder Rotator Cuff Healing in a Rabbit Model

作者：Zhang Shurong; Li Hong; Tao Hongyue; Li Hongyun; Cho Samson; Hua Yinghui; Chen Jiwu; Chen Shiyi; Li Yunxia^*

来源：The American Journal of Sports Medicine, 2013, 41(8): 1885-1892.

DOI：10.1177/0363546513493251

• rotator cuff healing
• passive motion
• biomechanical testing
• magnetic resonance imaging
• signal intensity

Background: Postoperative passive motion is the most widely accepted rehabilitation protocol after rotator cuff repair; however, a rotator cuff retear remains a frequent surgical complication. Clinical outcomes indicate that early passive motion is harmless to rotator cuff healing, but no laboratory evidence supports this proposition.
Hypotheses: (1) Immediate postoperative immobilization improves rotator cuff healing in rabbits. (2) Early passive motion after short-term immobilization does not harm rotator cuff healing in rabbits.
Study Design: Controlled laboratory study.
Methods: An injury to the supraspinatus tendon was created and repaired in 90 New Zealand White rabbits, after which they were randomly separated into 3 groups: (1) nonimmobilization (NI; n = 30), (2) continuous immobilization (IM; n = 30), and (3) immobilization with early passive motion (IP; n = 30). At 3, 6, and 12 weeks postoperatively, 5 rabbits from each group were sacrificed for histological evaluation, biomechanical testing, and magnetic resonance imaging.
Results: The histological study demonstrated better postoperative healing in the IM and IP groups, with clusters of chondrocytes accumulated at the tendon-bone junction. Magnetic resonance imaging illustrated that the tendon-bone junction was intact in the IM and IP groups. The magnetic resonance quantification analysis showed that the signal-to-noise quotient (SNQ) of the NI group was not significantly higher than that of the immobilization groups at 3 weeks (P = .232) or 6 weeks (P = .117), but it was significantly different at 12 weeks (NI vs IM, P = .006; NI vs IP, P = .009). At 12 weeks, the failure load was significantly higher in the IM and IP groups than in the NI group (NI vs IM, P = .002; NI vs IP, P = .002), but no difference was found between the IM and IP groups (P = .599).
Conclusion: Immediate postoperative immobilization led to better tendon-bone healing than immediate postoperative mobilization, and under immobilization, early passive motion was harmless to tendon-bone healing in this study.
Clinical Relevance: The results have an implication in supporting the rehabilitation protocol of early passive motion after rotator cuff repair.

• 出版日期2013-8
• 单位复旦大学