Acute effects of splint immobilization of the forearm on in vivo microcirculation and histomorphology of the human skin

Early weight bearing and mobilization decrease perioperative complications in patients after ankle fracture; the retrospective multicenter (TRON group) study

BACKGROUND

Open reduction and internal fixation (ORIF) for unstable ankle fractures (AF) are relatively predictable with excellent outcomes. Rehabilitation strategies are still being debated after surgical intervention for AF: non-weight bearing and cast immobilization for six weeks after the surgical repair of unstable AF or early functional treatment with partial weight bearing. This study aimed to compare early weight bearing and functional outcomes and complications.

METHODS

Between April 2014 and March 2019, 1421 patients with AF underwent ORIF at 11 institutions (TRON group). The patients were divided into two groups: Group E started weight bearing within six weeks after surgery, and group L started weightbearing for more than six weeks after. To adjust for baseline difference between groups, a propensity score-matched algorithm was used to match Group E with Group L in a 1:1 ratio of 294 cases each. We compared the American Orthopedic Foot and Ankle Society (AOFAS) score as the functional outcome, the rate of wound dehiscence, superficial and deep infections, blistering, nonunion, neurapraxia, and reoperation at 3, 6, and 12 months after surgery.

RESULTS

The mean period of non-weight bearing was significantly shorter in group E (3.68 ± 1.02 vs. 6.67 ± 1.43; P < 0.001). The mean period of cast immobilization term were shorter in group E (1.84 ± 1.35 vs. 2.65 ± 1.51; P < 0.001). There were no differences in the AOFAS score at any period. The rates of deep infection and reoperation in Group E were significantly lower than those in Group L (1.7% vs. 6.1%; P = 0.009, 2.0% vs. 7.8%; P = 0.002, respectively). There were no significant differences in superficial infection (9 vs. 15; P = 0.297), nonunion (9 vs. 15 P = 0.30), blistering (4 vs. 3; P = 1.00), neurapraxia (2 vs. 1; P = 1.00), and wound dehiscence (15 vs. 18; P = 0.72).

CONCLUSIONS

Although functional outcome was similar depending on whether early weight bearing was allowed, the rates of deep infection and reoperation decreased in patients with early weight bearing. We recommend early postoperative weight bearing in patients with a surgically treated AF.

Development and progression of immobilization-induced skin fibrosis through overexpression of transforming growth factor-ß1 and hypoxic conditions in a rat knee joint contracture model

PURPOSE

The purpose of this study was to investigate the pathology and mechanism of immobilization-induced skin fibrosis in a rat joint contracture model.

METHODS

Rats were randomly divided into control and immobilization groups. In the immobilization groups, knee joints of the rats were immobilized for 1, 2, and 4 weeks. After each immobilization, skin was dissected. To assess fibrosis in the skin, the thickness and area of adipocytes and connective tissue fibers were measured. Myofibroblasts were analyzed by immunohistochemistry by using anti-α-SMA as a marker. Gene expression levels of type I and III collagen, TGF-ß1, and HIF-1α were measured by using RT-PCR.

RESULTS

One week after immobilization, there was a marked increase in the area of connective tissue fibers in the immobilization group. Type I and type III collagen were significantly increased with prolonged immobilization. Higher numbers of α-SMA-positive cells were noted in the immobilized group at 2 and 4 weeks after immobilization. The expression level of TGF-β1 mRNA in the immobilization group increased after one week of immobilization. In contrast, the expression level of HIF1-α mRNA increased after 2 weeks of immobilization, and a greater increase was seen at 4 weeks after immobilization.

CONCLUSIONS

These results suggest that immobilization induces skin fibrosis with accumulation of types I and III collagen. These fibrotic changes may be evoked by upregulation of TGF-β1 after one week of immobilization. Additionally, upregulation of HIF-1α may relate to skin fibrosis by accelerating the differentiation of fibroblasts to myofibroblasts starting at 2 weeks after immobilization.

Cyclic muscle twitch contraction inhibits immobilization-induced muscle contracture and fibrosis in rats

We investigated the effects of cyclic muscle twitch contraction caused by neuromuscular electrical stimulation (NMES) on immobilization-induced muscle contracture and fibrosis in rats. Twenty-nine rats were divided into control, immobilization, and immobilization with muscle contraction groups. The ankle joints of the immobilization and muscle contraction rats were fixed in full plantar flexion with a plaster cast for 4 weeks. In the muscle contraction group, cyclic muscle twitch contraction of the soleus muscle was induced using a commercial device (1 Hz, 4 ± 2 mA, 60 min/day, 5 times/week) with the ankle joint immobilized. The dorsiflexion range of ankle joint motion in the muscle contraction group was significantly greater than that in the immobilization group. The expressions of fibrosis-related genes (i.e., hypoxia inducible factor-1α, transforming growth factor-β1, α-smooth muscle actin, and types I and III collagen) were significantly decreased in the muscle contraction group compared to the immobilization group. The fluorescence intensities of type I and type III collagen in the perimysium and endomysium in the muscle contraction group were significantly decreased compared to the immobilization group. These results suggest that cyclic muscle twitch contraction induced by NMES might alleviate skeletal muscle fibrosis, reducing immobilization-induced muscle contracture.