A retrospective comparative study of surgical outcomes following femoral fascia patching and iliotibial ligament bony patching for primary irreparable rotator cuff tears in a geriatric population.

INTRODUCTION: We performed two surgical techniques for primary irreparable rotator cuff tears: a patch technique using the femoral fascia as a graft (F technique) and a patch technique using the bony iliotibial ligament (I technique). We then evaluated the outcomes of both surgical methods. MATERIALS AND METHODS: This study included 28 patients who were diagnosed with primary irreparable rotator cuff tears from April 2008 to April 2014. Among them, 13 underwent the F technique, whereas 15 underwent the I technique. Each clinical shoulder score was evaluated preoperatively and 2 years after surgery. The cuff integrity was evaluated via magnetic resonance imaging 2 years after surgery, with cases suffering a retear after surgery undergoing retear site examination. In group I, computed tomography (CT) was performed 3-4 months after surgery to investigate the bony part of the patch and bony fusion of the footprint. RESULTS: Both groups showed significant improvements in the pre- and postoperative mean clinical score values. Group I had significantly better postoperative scores than group F. Postoperative retear rates were 33.3% and 76.9% for groups I and F, respectively, with group I having a significantly lower retear rate (P = 0.03). All 5 retears in group I were located at the suture between the residual rotator cuff and the graft, whereas 7 of the 10 retears in group F were located at the fixation of the graft and footprint and the remaining 3 were central. CT results in group I showed that all 15 patients had bony fusion between the bony part of the patch and the footprint. CONCLUSION: The I technique was significantly superior to the F technique in terms of postoperative clinical scores and retear rates, suggesting its advantage for rotator cuff tissue reconstruction.

Short-term immunosuppression and surgical neoangiogenesis with host vessels maintains long-term viability of vascularized bone allografts.

Currently available methods to reconstruct large skeletal defects have limitations. These include nonunion and stress fractures in structural allografts, and inability to match the size, shape, and/or strength of most recipient sites using vascularized fibular autografts. Prosthetic diaphyseal replacements may loosen or produce periprosthetic fractures. Transplantation of living allogenic bone would enable matching donor bone to the recipient site, combined with the desirable healing and remodeling properties of living bone. We propose a novel method by which the transplantation of such tissue might be done without the risks of life-long immunosuppression, using surgical neoangiogenesis to develop a new host-derived osseous blood supply. We performed vascularized femoral allografts from 86 female Dark Agouti donor rats to male Piebald Virol Glaxo recipients across a major histocompatibility (MHC) barrier. In addition to microvascular reconstruction of the nutrient vessel, we surgically implanted a host arteriovenous (AV) bundle into the medullary canal to promote host vessel neoangiogenesis. Independent variables included patency of the implanted AV bundle, and use of 2 weeks' FK-506 immunosuppression. After 18 weeks, bone blood flow was measured, and neoangiogenic capillary density quantified. Bone blood flow and capillary density were significantly greater in transiently immunosuppressed recipients with a patent AV pedicle. We conclude that neoangiogenesis from implanted host-derived AV-bundles, combined with short-term immunosuppression maintains blood flow in vascularized bone allografts, and offers potential for clinical application.

Skeletal reconstruction by vascularized allogenic bone transplantation: effects of statin in rats.

BACKGROUND: Some statins have been reported to suppress the immune system and increase the expression of bone morphogenetic protein-2 gene that plays a pivotal role in bone regeneration. METHODS: The effects of cerivastatin on skeletal reconstruction by vascularized bone allograft were investigated in a rat tibia-fibula graft model. After transplantation, the recipient rats were treated with vehicle, low-dose cerivastatin, high-dose cerivastatin, or cyclosporine A. RESULTS: Transplanted bones treated with low-dose cerivastatin and vehicle failed to unite with the recipient bones. In contrast, high-dose cerivastatin induced the bone union as effectively as cyclosporine A. Histologically, high-dose cerivastatin-treated transplanted bones were nonvital, but new bone formation occurred at the outer layer of the nonvital cortex. CONCLUSION: These results indicate that statins could promote fracture healing. Because transplant recipients have the increased risks of osteoporotic fracture and hypercholesterolemia, statins may be a good choice in the treatment of these patients.

Role of vascularised tissue transfer after oncological resection in the upper extremity.

We reviewed 12 patients who had had vascularised tissue transfer after oncological resection in the upper extremity. All patients had immediate reconstruction, and one had a double tissue transfer. Tissues used were skin flaps, free muscles, and vascularised fibulas, for resurfacing the wound, motor recovery, and reconstruction of large bony defects, respectively. All the patients returned early to their daily activities. Although local recurrences were encountered in two patients, they were again rendered disease-free by salvage operations. Two patients had secondary reconstructions using pedicle latissimus dorsi flaps for late problems, including one of the two patients who developed a local recurrence. The mean functional score using the system devised by the Musculoskeletal Tumor Society was 84%. All the upper extremities were successfully rescued with satisfactory function. Vascularised tissue transfer was invaluable for achieving both curative resection of the tumour and a useful upper extremity.

Host-derived angiogenesis maintains bone blood flow after withdrawal of immunosuppression.

A novel method of living bone allotransplantation combining microvascular repair of the nutrient circulation, implantation of host-derived arteriovenous (AV) bundles, and short-term immunosuppression is described. We hypothesized that neoangiogenesis from the implanted vessels would maintain graft viability and circulation after withdrawal of FK506 (Tacrolimus) immunosuppression. Vascularized femoral transplantation was performed between DA and PVG rats. In addition to microsurgical pedicle anastomoses, a saphenous AV bundle from the recipient animal was implanted in the medullary space. Ninety-seven rats were randomly allocated to groups differing in immunosuppression and AV bundle patency. Implanted vessels significantly improved capillary density and bone blood flow in nonimmunosuppressed and immmunosuppressed groups, respectively. A lower incidence of spontaneous AV bundle thrombosis was found with Tacrolimus treatment. More viable osteocytes were seen at 4 weeks when the AV bundle was patent. Further investigations may confirm host-derived neoangiogenesis as an alternative to tolerance induction or immunosuppression in bone allotransplantation.

Sequential treatment with intermittent low-dose human parathyroid hormone (1-34) and bisphosphonate enhances large-size skeletal reconstruction by vascularized bone transplantation.

Vascularized bone transplantation enables reconstruction of large skeletal defects, but this process needs a long time. Since short-term intermittent parathyroid hormone (PTH) enhances rat fracture healing, we investigated the effects of 4-week intermittent low-dose (10 microg/kg/day) or high-dose (100 microg/kg/day) PTH followed by 4-week vehicle, low-dose or high-dose intermittent PTH, or zoledronic acid (ZOL, 2 micro/kg/week), a potent bisphosphonate, on large skeletal reconstruction by vascularized tibial grafting in rats. Compared to 8-week vehicle, 8-week low-dose PTH did not significantly increase the serum osteocalcin level as well as the urinary deoxypyridinoline level, while 4-week low-dose or high-dose PTH followed by 4-week ZOL decreased both of these levels. Eight-week PTH increased the bone mass of the graft and strength of the reconstructed skeleton in a dose-dependent manner; notably, the reconstructed skeleton showed an obviously higher response to PTH compared to the contralateral nonoperated femur. In contrast, 4-week PTH followed by 4-week vehicle reduced these effects and caused local bone loss at the host-graft junctions. Four-week PTH followed by 4-week ZOL did not induce such bone loss; however, 4-week high-dose PTH followed by 4-week ZOL caused a large callus in the distal cortical junction. Four-week PTH followed by 4-week ZOL increased the bone mass and strength similarly to 8-week PTH. These preliminary findings suggest, for the first time, that sequential treatment with short-term intermittent low-dose PTH and bisphosphonate as well as long-term intermittent low-dose PTH treatment enhance large skeletal reconstruction by vascularized bone transplantation, though early timing of sequential antiresorptive treatment could result in delay of bone repair.