Effect of difference in fixation methods of tendon graft and the microfracture procedure on tendon-bone junction healing.

BACKGROUND: There are generally two methods of fixation for tendon grafts used in ligament reconstruction: bone tunnel fixation and anchor fixation. The microfracture (Mf) procedure is a technique to induce bleeding from the bone marrow, and the bleeding may contain cells with differentiation potential. However, few studies have compared the effects of the Mf procedure with those of the fixation methods. This study aimed to evaluate the effectiveness of the Mf procedure on two tendon graft fixation methods: histological, gene expression, tendon graft thickness, and mechanical. We especially focused our investigation on junction healing of tendon grafts and bone in the two fixation methods. METHODS: We used 20 rabbits to evaluate tendon and bone healing in a peroneal tendon graft model. The rabbit models were divided into five groups according to the combination of peroneal tendon graft fixation method and Mf technique as follows: control group (C, n = 4), bone tunnel fixation without Mf procedure group (BT - Mf, n = 4), bone tunnel fixation with Mf procedure group (BT + Mf, n = 4), anchor fixation without Mf procedure group (A - Mf, n = 4), and anchor fixation with Mf procedure group (A + Mf, n = 4). All animals were sacrificed at 4 weeks postoperatively. The specimens underwent histological evaluation, mRNA analysis, tendon graft thickness at the tendon-bone junction, and biomechanical testing. RESULTS: Histological evaluation of the BT + Mf and A + Mf groups showed healing with fibrocartilage formation at the tendon graft-bone junction. The mRNA expression showed significant increase in type 2 collagen, Scleraxis, and SRY-box9 in the BT + Mf and A + Mf groups. In biomechanical tests, the BT + Mf and A + Mf groups showed significantly increased tensile strength compared with the BT - Mf and A - Mf groups (BT + Mf group, 21.6 ± 1.7 N; A + Mf group, 22.5 ± 2.3 N vs. BT - Mf group, 12.3 ± 2.4 N; A - Mf group, 11 ± 2.3 N). CONCLUSION: The Mf procedure resulted in fibrocartilage formation at the tendon-bone junction in the BT and anchor fixation and improved the fixation strength at 4 weeks.

The effect of mechanical stress on enthesis homeostasis in a rat Achilles enthesis organ culture model.

Tendons and ligaments are jointed to bones via an enthesis that is essential to the proper function of the muscular and skeletal structures. The aim of the study is to investigate the effect of mechanical stress on the enthesis. We used ex vivo models in organ cultures of rat Achilles tendons with calcaneus including the enthesis. The organ was attached to a mechanical stretching apparatus that can conduct cyclic tensile strain. We made the models of 1-mm elongation (0.5 Hz, 3% elongation), 2-mm elongation (0.5 Hz, 5% elongation), and no stress. Histological evaluation by Safranin O staining and Toluidin Blue and Picro Sirius red staining was conducted. Expression of sex-determining region Y-box 9 (Sox9), scleraxis (Scx), Runt-related transcription factor 2 (Runx2), and matrix metalloproteinase 13 (Mmp13) were examined by real-time polymerase chain reaction and immunocytochemistry. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end-labeling and live/dead staining and was conducted for evaluation of the apoptosis and cell viability. The structure of the enthesis was most maintained in the model of 1-mm elongation. The electronic microscope showed that the enthesis of the no stress model had ill-defined borders between fibrocartilage and mineralized fibrocartilage, and that calcification of mineralized fibrocartilage occurred in the model of 2-mm elongation. Sox9 and Scx was upregulated by 1-mm elongation, whereas Runx2 and Mmp13 were upregulated by 2-mm elongation. Apoptosis was inhibited by low stress. The results of this study suggested that 1-mm elongation can maintain the structure of the enthesis, while 2-mm elongation promotes degenerative changes.

The trend of treatment and conveyance system for upper extremity replantation in Japan: A nationwide population-based study from the Japan trauma data bank.

BACKGROUND: In Japan, microsurgical skill development and a system to transfer patients to an appropriate hospital for upper extremity amputation have been promoted; however, information about trends of replantation is limited. Therefore, the aim of this study was to clarify the trends in the treatment for upper extremity amputation using the Japan Trauma Data Bank (JTDB). METHODS: Data derived from JTDB (2004-2015) were used to quantify trends in the volume of replantation for upper extremity amputation including finger amputation. Trauma was diagnosed based on the Abbreviated Injury Scale code; a subgroup of patients who underwent replantation was delineated. We investigated patient demographics, infection rate, and characteristics of treating facilities. RESULTS: A total of 1240 patients underwent upper extremity amputation. Among these, 510 (41.1%) underwent replantation, and the rate of replantation did not change over the study period. The average age of patients who underwent or did not undergo replantation was 45.5 and 47.2 years, respectively. The proportion of the patients who were transferred to another hospital for treatment significantly decreased between 2004 (28.5%) and 2015 (16.3%) (P < 0.01). Time taken for transfer from the accident site to hospitals increased. The rate of patients who underwent replantation differed among different hospitals; however, higher-volume hospitals were more likely to perform replantation. CONCLUSION: The rate of patients transferred to another hospital decreased between 2004 and 2015; however, the rate of patients who underwent replantation remained unchanged. This suggests that the number of patients who were transported directly from the accident site to an appropriate hospital has increased, whereas the indication for care in each hospital remains unchanged. Common criteria for amputations are needed to address the differing rates of replantation among hospitals.

The Masquelet technique for septic arthritis of the small joint in the hands: Case reports.

Septic arthritis in distal interphalangeal (DIP) joints sometimes occurs in association with mucous cysts or after the surgical treatment of mallet fingers. Recently, several studies have demonstrated the effectiveness of the Masquelet technique in the treatment of bone defects caused by trauma or infection. However, only few studies have reported the use of this technique for septic arthritis in small joints of the hand, and its effectiveness in treating septic arthritis in DIP joints remains unclear. We report the clinical and radiological outcomes of three patients who were treated with the Masquelet technique for septic arthritis in DIP joints. One patient had uncontrolled diabetes and another had rheumatoid arthritis treated with methotrexate and prednisolone. The first surgical stage involved thorough debridement of the infection site, including the middle and distal phalanx. We placed an external fixator from the middle to the distal phalanx and then packed the cavity of the DIP joint with antibiotic cement bead of polymethylmethacrylate (40 g) including 2 g of vancomycin and 200 mg of minocycline. At 4-6 weeks after the first surgical stage, the infection had cleared, and the second surgical stage was performed. The external fixator and cement bead were carefully removed while carefully preserving the surrounding osteo-induced membrane. The membrane was smooth and nonadherent to the cement block. In the second surgical stage, an autogenous bone graft was harvested from the iliac bone and inserted into the joint space, within the membrane. The bone graft, distal phalanx, and middle phalanx were fixed with Kirschner wires and/or a soft wire. Despite the high risk of infection, bone union was achieved in all patients without recurrence of infection. Although the Masquelet technique requires two surgeries, it can lead to favorable clinical and radiological outcomes for infected small joints of the hand.