Safety and clinical efficacy of double posterolateral coaxial portals for endoscopic management of posterior ankle impingement syndrome.

Background: This study aims to analyze the safety and clinical efficacy of using double posterolateral coaxial portals for endoscopic treatment of posterior ankle impingement syndrome (PAIS), a procedure that has gained popularity in recent times. Methods: Six fresh foot samples were randomly selected to measure the distances of two posterolateral portals to the sural nerve in different positions (plantar flexion 10°, dorsiflexion 30°, and plantar flexion 30°) for safety evaluation. A prospective analysis was conducted on the clinical efficacy of the operative approach for endoscopic management of posterior ankle impingement syndrome, including evaluation of effectiveness and complications. Results: In this study, the mean distances of the first and second portals to the sural nerve were measured in different ankle positions. The distances were found to be 2.26 ± 0.22 cm and 1.59 ± 0.12 cm in the plantar flexion 10° position, 2.21 ± 0.21 cm and 1.55 ± 0.12 cm in the dorsiflexion 30° position, and 2.46 ± 0.29 cm and 1.73 ± 0.19 cm in the plantar flexion 30° position, demonstrating a significant safety margin from the nerve. A total of 38 patients underwent endoscopic treatment for posterior ankle impingement syndrome using double posterolateral coaxial portals between January 2012 and December 2017. This surgical approach provided access to the subtalar joint and posterior ankle region. The patients were followed up for an average of 38.2 months (24-72 months), with a satisfaction rate of 94.7%. There were no reported complications, and significant improvements were observed in both visual analogue scale (VAS) and The American Orthopedic Foot and Ankle Society Score (AOFAS) scores postoperatively. The VAS score decreased from 5.68 to 0.51 (P < 0.001), while the AOFAS score increased from 71.68 to 92.34 (P < 0.001), resulting in an excellent/good rate of 97.3%. Conclusion: The use of double posterolateral coaxial portals in the treatment of posterior ankle impingement syndrome offers several advantages, including improved safety, reduced risk of nerve injury, enhanced visualization of the posterior ankle and subtalar joint, favorable clinical outcomes, and minimal complications.

Histologic and biomechanical evaluation of the thoracolumbar fascia graft for massive rotator cuff tears in a rat model.

BACKGROUND: Fascial autografts, which are easily available grafts, have provided a promising option in patients with massive rotator cuff tears. However, no fascial autografts other than the fascia lata have been reported, and the exact healing process of the fascia-to-bone interface is not well understood. The objective of this study is to histologically and biomechanically evaluate the effect of the thoracolumbar fascia (TLF) on fascia-to-bone healing. METHODS: A total of 88 rats were used in this study. Eight rats were killed at the beginning to form an intact control group, and the other rats were divided randomly into 2 groups (40 rats per group): the TLF augmentation group (TLF group) and the repair group (R group). The right supraspinatus was detached, and a 3 × 5 mm defect of the supraspinatus was created. The TLF was used to augment the torn supraspinatus in the TLF group, whereas in the R group, the torn supraspinatus was repaired in only a transosseous manner. Histology and biomechanics were assessed at 1, 2, 4, 8, and 16 weeks postoperatively. RESULTS: The modified tendon maturation score of the TLF group was higher than that of the R group at 8 weeks (23.00 ± 0.71 vs. 24.40 ± 0.89, P = .025) and 16 weeks (24.60 ± 0.55 vs. 26.40 ± 0.55, P ≤ .001). The TLF group showed a rapid vascular reaction, and the peak value appeared at 1 week. Later, the capillary density decreased, and almost no angiogenesis was observed at 8 weeks postoperatively. Immunohistochemistry results demonstrated a significantly higher percentage of collagen I in the TLF group at 4, 8, and 16 weeks (24.78% ± 2.76% vs. 20.67% ± 2.11% at 4 weeks, P = .046; 25.46% ± 1.77% vs. 21.49% ± 2.33% at 8 weeks, P = .026; 34.77% ± 2.25% vs. 30.01% ± 3.17% at 16 weeks, P = .040) postoperatively. Biomechanical tests revealed that the ultimate failure force in the TLF group was significantly higher than that in the R group at the final evaluation (29.13 ± 2.49 N vs. 23.10 ± 3.47 N, P = .022). CONCLUSIONS: The TLF autograft can promote a faster biological healing process and a better fixation strength. It could be used as an alternative reinforcement or bridging patch when the fascia lata is not appropriate or available for superior capsule reconstruction (SCR).

Interleukin-15 facilitates muscle regeneration through modulation of fibro/adipogenic progenitors.

BACKGROUND: Chronic muscle injury is characteristics of fatty infiltration and fibrosis. Recently, fibro/adipogenic progenitors (FAPs) were found to be indispensable for muscular regeneration while were also responsible for fibrosis and fatty infiltration in muscle injury. Many myokines have been proven to regulate the adipose or cell proliferation. Because the fate of FAPs is largely dependent on microenvironment and the regulation of myokines on FAPs is still unclear. We screened the potential myokines and found Interleukin-15 (IL-15) may regulate the fatty infiltration in muscle injury. In this study, we investigated how IL-15 regulated FAPs in muscle injury and the effect on muscle regeneration. METHODS: Cell proliferation assay, western blots, qRT-PCR, immunohistochemistry, flow cytometric analysis were performed to investigate the effect of IL-15 on proliferation and adipogensis of FAPs. Acute muscle injury was induced by injection of glycerol or cardiotoxin to analyze how IL-15 effected on FAPs in vivo and its function on fatty infiltration or muscle regeneration. RESULTS: We identified that the expression of IL-15 in injured muscle was negatively associated with fatty infiltration. IL-15 can stimulate the proliferation of FAPs and prevent the adipogenesis of FAPs in vitro and in vivo. The growth of FAPs caused by IL-15 was mediated through JAK-STAT pathway. In addition, desert hedgehog pathway may participate in IL-15 inhibiting adipogenesis of FAPs. Our study showed IL-15 can cause the fibrosis after muscle damage and promote the myofiber regeneration. Finally, the expression of IL-15 was positively associated with severity of fibrosis and number of FAPs in patients with chronic rotator cuff tear. CONCLUSIONS: These findings supported the potential role of IL-15 as a modulator on fate of FAPs in injured muscle and as a novel therapy for chronic muscle injury.