Shoulder pathoanatomy in marathon kayakers.

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Abstract

[Indexed for MEDLINE] 17. Am J Sports Med. 2023 Oct;51(12):3243-3250. doi: 10.1177/03635465231191779. Epub 2023 Sep 8. The Effect of Combining Hyaluronic Acid and Human Dermal Fibroblasts on Tendon Healing. Rhee SM(1), Jeon S(2), Han J(2), Kim YH(2), Jeong HJ(3), Park JH(4), Oh JH(3). Author information: (1)Shoulder & Elbow Clinic, Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University, Seoul, Republic of Korea. (2)Cutigen Research Institute, Tego Science Inc, Seoul, Republic of Korea. (3)Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea. (4)Department of Orthopaedic Surgery, College of Medicine, Dongguk University Hospital, Goyang-si, Republic of Korea. BACKGROUND: The incidence of rotator cuff tears is rapidly increasing, and operative techniques for rotator cuff repair have been developed. However, the rates of postoperative retear remain high. PURPOSE/HYPOTHESIS: The purpose was to determine the effects of human dermal fibroblasts (HDFs) with hyaluronic acid (HA) on tendon-to-bone healing in a rabbit model of chronic rotator cuff tear injury. It was hypothesized that HA would enhance HDF proliferation and that a combination of HA and HDFs would produce a synergistic effect on the healing of repaired rotator cuff tendons of rabbits. STUDY DESIGN: Controlled laboratory study. METHODS: For in vitro study, HDFs were plated on a 24-well plate. After 1 day, 2 wells were designated as the test group and treated with 0.75% HA in phenol red-free Dulbecco's modified Eagle medium (DMEM). An other 2 wells served as control groups and were treated with the same volume of phenol red-free DMEM without HA. Each group was duplicated, resulting in a total of 4 wells, with 2 wells in each group for replication purposes. The cells were incubated for 24 hours, followed by 72-hour cultivation. Absorbance ratios at 96 and 24 hours were compared to evaluate cell proliferation. For the in vivo study, a total of 24 rabbits were randomly allocated to groups A, B, and C (n = 8 each). Supraspinatus tendons were detached bilaterally and left for 6 weeks to establish a chronic rotator tear model. Torn tendons were subsequently repaired using the following injections: group A, 0.5 × 106 HDFs with HA; group B, HA only; and group C, saline only. At 12 weeks after repair, biomechanical tests and histological evaluation were performed. RESULTS: In vitro study showed that HDF proliferation significantly increased with HA (HDFs with HA vs HDFs without HA; 3.96 ± 0.09 vs 2.53 ± 0.15; P < .01). In vivo, group A showed significantly higher load-to-failure values than the other groups (53.8 ± 6.9 N/kg for group A, 30.6 ± 6.4 N/kg for group B, and 24.3 ± 7.6 N/kg for group C; P < .001). Histological evaluation confirmed that group A showed higher collagen fiber density and better collagen fiber continuity, tendon-to-bone interface maturation, and nuclear shape than the other groups (all P < .05). CONCLUSION: This controlled laboratory study verified the potential of the combination of HDFs and HA in enhancing healing in a chronic rotator cuff tear rabbit model. CLINICAL RELEVANCE: A potential synergistic effect on rotator cuff tendon healing may be expected from a combination of HDFs and HA. DOI: 10.1177/03635465231191779