Outcomes of Surface Replacement Proximal Interphalangeal Joint Arthroplasty Using the Self Locking Finger Joint Implant: Minimum Two Years Follow-up.

BACKGROUND: The Self Locking Finger Joint (SLFJ) implant is a new type of surface replacement implant. The purpose of this study was to evaluate midterm clinical outcomes of the proximal interphalangeal (PIP) arthroplasty with the SLFJ implant. METHODS: We retrospectively studied 26 PIP joint arthroplasties using the SLFJ implant in 17 patients with osteoarthritis or posttraumatic osteoarthritis. Preoperative and postoperative range of motion, grip strength and key pinch, radiographic findings, and complications were evaluated. The Disabilities of the Arm, Shoulder, and Hand (DASH) score, visual analog scale (VAS) score, course of pain, and patient satisfaction were obtained. RESULTS: The mean follow-up time was 44 months (range, 24-76 months). The average active PIP joint arc of motion improved from 36° before surgery to 44° after surgery. Grip strength and key pinch showed no statistical difference between preoperative and postoperative assessments. The average DASH score and VAS score improved from 40 to 15 and from 5 to 1, respectively. Overall patient satisfaction was 94%. Ninety percent of implants showed osteointegration, and there were no radiographic signs of migration and loosening. Three joints (12%) showed abnormal heterotopic bone formation. Four joints (15%) had secondary surgery-1 joint needing joint head and socket replacement and 3 joints needing contracture release. CONCLUSIONS: Our minimum 2 years of follow-up evaluation of the SLFJ implant PIP joint arthroplasty demonstrated good pain relief and good overall patient satisfaction while maintaining joint range of motion. The SLFJ implant showed good osteointegration. Further longer-term prospective studies with various types of currently available implants are needed.

Tendon Stem Cells: Mechanobiology and Development of Tendinopathy.

Millions of people suffer from tendon injuries in both occupational and athletic settings. However, the restoration of normal structure and function to injured tendons still remains as one of the greatest challenges in orthopaedics and sports medicine. In recent years, a remarkable advancement in tendon research field has been the discovery of tendon stem/progenitor cells (TSCs). Unlike tenocytes, the predominant resident cell in tendons, TSCs have the ability to self-renew and multi-differentiate. Because of these distinct properties, TSCs may play a critical role in tendon physiology as well as pathology such as tendinopathy, which is a prevalent chronic tendon injury. Additionally, because TSCs are tendon-specific stem cells, they could potentially be used in tendon tissue engineering in vitro, and serve as a promising cell source for cell-based therapy to effectively repair or even regenerate injured tendons in clinical settings.

The effect of tendon stem/progenitor cell (TSC) sheet on the early tendon healing in a rat Achilles tendon injury model.

UNLABELLED: Tissue-engineering approaches have a great potential to improve the treatment of tendon injuries that affect millions of people. The present study tested the hypothesis that introduction of a tendon derived stem/progenitor cell (TSC) sheet accelerates tendon healing and tendon regeneration in a rat model. TSC sheets were produced on temperature-responsive culture dishes. Then, they were grafted on unwounded Achilles tendons and at sites of a 3mm of Achilles tendon defect. At 2 and 4weeks after implantation tendons were examined by histology, immunohistochemistry, transmission electron microscopy (TEM) and mechanical testing. The results showed that the implanted TSC sheet remained stably attached on the tendon surface at 4 weeks after implantation. Moreover, in the tendon defect model, tendon defect area where TSC sheet was implanted was well regenerated and had better organized collagen fibers with elongated spindle shaped cells, compared to relatively disorganized collagen fibers and round shaped cells in the control group. TEM observations revealed longitudinally aligned collagen fibers and thick collagen fibrils in the TSC sheet implanted group. Finally, at 4weeks mechanical property of the TSC sheet implanted tendon had better ultimate load than the control. In conclusion, this study demonstrates the feasibility of implanting TSC sheets on tendons in vivo. Introduction of the cell sheets into a tendon defect significantly improved histological properties and collagen content at both 2 and 4 weeks after implantation, indicating that TSC sheets may effectively promote tendon remodeling in the early stages of tendon healing. STATEMENT OF SIGNIFICANCE: Tendon injury is a highly prevalent clinical problem that debilitates millions of people worldwide in both occupational and athletic settings. It also costs billions of healthcare dollars in treatment every year. In this study, we showed the feasibility of using tendon derived stem cell sheet to deliver biologically active tenogenic-constructs and promote tendon regeneration. This work has the potential to impact the orthopaedic surgery and sports medicine fields in the treatment of tendon injury.

Interstitial engraftment of adipose-derived stem cells into an acellular dermal matrix results in improved inward angiogenesis and tissue incorporation.

Acellular dermal matrices (ADM) are commonly used in reconstructive procedures and rely on host cell invasion to become incorporated into host tissues. We investigated different approaches to adipose-derived stem cells (ASCs) engraftment into ADM to enhance this process. Lewis rat adipose-derived stem cells were isolated and grafted (3.0 × 10(5) cells) to porcine ADM disks (1.5 mm thick × 6 mm diameter) using either passive onlay or interstitial injection seeding techniques. Following incubation, seeding efficiency and seeded cell viability were measured in vitro. In addition, Eighteen Lewis rats underwent subcutaneous placement of ADM disk either as control or seeded with PKH67 labeled ASCs. ADM disks were seeded with ASCs using either onlay or injection techniques. On day 7 and or 14, ADM disks were harvested and analyzed for host cell infiltration. Onlay and injection techniques resulted in unique seeding patterns; however cell seeding efficiency and cell viability were similar. In-vivo studies showed significantly increased host cell infiltration towards the ASCs foci following injection seeding in comparison to control group (p < 0.05). Moreover, regional endothelial cell invasion was significantly greater in ASCs injected grafts in comparison to onlay seeding (p < 0.05). ADM can successfully be engrafted with ASCs. Interstitial engraftment of ASCs into ADM via injection enhances regional infiltration of host cells and angiogenesis, whereas onlay seeding showed relatively broad and superficial cell infiltration. These findings may be applied to improve the incorporation of avascular engineered constructs.

Tissue engraftment of hypoxic-preconditioned adipose-derived stem cells improves flap viability.

Adipose-derived stem cells (ASCs) have the ability to release multiple growth factors in response to hypoxia. In this study, we investigated the potential of ASCs to prevent tissue ischemia. We found conditioned media from hypoxic ASCs had increased levels of vascular endothelial growth factor (VEGF) and enhanced endothelial cell tubule formation. To investigate the effect of injecting rat ASCs into ischemic flaps, 21 Lewis rats were divided into three groups: control, normal oxygen ASCs (10(6) cells), and hypoxic preconditioned ASCs (10(6) cells). At the time of flap elevation, the distal third of the flap was injected with the treatment group. At 7 days post flap elevation, flap viability was significantly improved with injection of hypoxic preconditioned ASCs. Cluster of differentiation-31-positive cells were more abundant along the margins of flaps injected with ASCs. Fluorescent labeled ASCs localized aside blood vessels or throughout the tissue, dependent on oxygen preconditioning status. Next, we evaluated the effect of hypoxic preconditioning on ASC migration and chemotaxis. Hypoxia did not affect ASC migration on scratch assay or chemotaxis to collagen and laminin. Thus, hypoxic preconditioning of injected ASCs improves flap viability likely through the effects of VEGF release. These effects are modest and represent the limitations of cellular and growth factor-induced angiogenesis in the acute setting of ischemia.

The current role of the vascularized-fibular osteocutaneous graft in the treatment of segmental defects of the upper extremity.

Large osseous defects of the upper extremity can be a challenging problem for the reconstructive surgeon. There are numerous treatment options reported in the literature with variable results. We review our experience with the vascularized-fibular osteocutaneous graft for these complex defects with a focus on surgical techniques and outcomes.

Dupuytren's fibroblast contractility by sphingosine-1-phosphate is mediated through non-muscle myosin II.

PURPOSE: Previous studies suggest that Dupuytren's disease is caused by fibroblast and myofibroblast contractility within Dupuytren's nodules; however, the stimulus for cell contractility is unknown. Sphingosine-1-phosphate (S1P) is a serum-derived lysophospholipid mediator that enhances cell contractility by activating the S1P receptor, S1P(2). It is hypothesized that S1P stimulates Dupuytren's fibroblast contractility through S1P(2) activation of non-muscle myosin II (NMMII). This investigation examined the role of S1P and NMMII activation in Dupuytren's disease progression and suggests potential targets for treatment. METHODS: We enmeshed Dupuytren's fibroblasts into fibroblast-populated collagen lattices (FPCLs) and assayed S1P-stimulated FPCL contraction in the presence of the S1P(2) receptor inhibitor JTE-013, the Rho kinase inhibitor Y-27632, the myosin light chain kinase inhibitor ML-7, and the NMMII inhibitor blebbistatin. Tissues from Dupuytren's fascia (n = 10) and normal palmar fascia (n = 10) were immunostained for NMMIIA and NMMIIB. RESULTS: Sphingosine-1-phosphate stimulated FPCL contraction in a dose-dependent manner. Inhibition of S1P(2) and NMMII prevented S1P-stimulated FPCL contraction. Rho kinase and myosin light chain kinase inhibited both S1P and control FPCL contraction. Dupuytren's nodule fibroblasts robustly expressed NMMIIA and NMMIIB, compared with quiescent-appearing cords and normal palmar fascia. CONCLUSIONS: Sphingosine-1-phosphate promotes Dupuytren's fibroblast contractility through S1P(2), which stimulates activation of NMMII. NMMII isoforms are ubiquitously expressed throughout Dupuytren's nodules, which suggests that nodule fibroblasts are primed to respond to S1P stimulation to cause contracture formation. S1P-promoted activation of NMMII may be a target for disease treatment.

A model of sequential heart and composite tissue allotransplant in rats.

BACKGROUND: Some of the 600,000 patients with solid organ allotransplants need reconstruction with a composite tissue allotransplant, such as the hand, abdominal wall, or face. The aim of this study was to develop a rat model for assessing the effects of a secondary composite tissue allotransplant on a primary heart allotransplant. METHODS: Hearts of Wistar Kyoto rats were harvested and transplanted heterotopically to the neck of recipient Fisher 344 rats. The anastomoses were performed between the donor brachiocephalic artery and the recipient left common carotid artery, and between the donor pulmonary artery and the recipient external jugular vein. Recipients received cyclosporine A for 10 days only. Heart rate was assessed noninvasively. The sequential composite tissue allotransplant consisted of a 3 x 3-cm abdominal musculocutaneous flap harvested from Lewis rats and transplanted to the abdomen of the heart allotransplant recipients. The abdominal flap vessels were connected to the femoral vessels. No further immunosuppression was administered following the composite tissue allotransplant. Ten days after composite tissue allotransplantation, rejection of the heart and abdominal flap was assessed histologically. RESULTS: The rat survival rate of the two-stage transplant surgery was 80 percent. The transplanted heart rate decreased from 150 +/- 22 beats per minute immediately after transplant to 83 +/- 12 beats per minute on day 20 (10 days after stopping immunosuppression). CONCLUSIONS: This sequential allotransplant model is technically demanding. It will facilitate investigation of the effects of a secondary composite tissue allotransplant following primary solid organ transplantation and could be useful in developing future immunotherapeutic strategies.

Development of a simple model for predicting need for surgery in patients who initially undergo conservative management for adhesive small bowel obstruction.

BACKGROUND: Among patients with adhesive small bowel obstruction (ASBO) initially managed with a conservative strategy, predicting risk of operation is difficult. METHODS: We investigated ASBO patients at 2 different periods to derive and validate a clinical prediction model for risk of operation. RESULTS: One hundred fifty-four patients were enrolled into the derivation cohort and 96 into the validation cohort. Based on the derived scoring, including age > or =65 years, presence of ascites, and gastrointestinal drainage volume >500 mL on day 3, each patient was classified into 1 of 4 risk classes from low risk to high risk. When applied to the validation cohort, the positive predictive value (PPV) for operation in the high-risk class was 72%, while the negative predictive value (NPV) in the low-risk class was 100% with high sensitivity (100%) and specificity (96%). CONCLUSIONS: The prediction model performs well for risk stratification of need for surgical intervention following conservative strategy among ASBO patients.

Longitudinal outcomes and application of the subunit principle to 165 foot and ankle free tissue transfers.

BACKGROUND: Free tissue transfer to the lower extremity has become a well-established reconstructive modality. The purpose of this study was to develop a "subunit" approach to patients undergoing free tissue transfer for foot and ankle wounds to help further define subunit-specific functional and aesthetic operative goals. METHODS: The institutional review board approved this retrospective review of 161 patients who underwent free tissue transplantation for foot and ankle wounds between March 1, 1997, and February 28, 2007, at a single institution. Endpoints included flap-related complications, secondary surgery, time to ambulation, flap stability, and limb salvage. RESULTS: The most common types of wounds treated were trauma-related [n = 120 (75 percent)], diabetes-related [n = 24 (15 percent)], and oncologic defects [n = 8 (5 percent)]. Ten different donor sites were used for reconstruction, with the latissimus dorsi flap being the most common. The mean follow-up time was 26.9 months (range, 0.5 to 130 months). Mean time to ambulation was 3.1 months (range, 0.75 to 14 months). Overall, 11 percent of patients required revision surgery for flap instability at a mean time of 25.3 months after flap surgery. Wounds located over the heel (subunit 5) were most likely to develop instability (Fisher's exact test, p < 0.05). The overall 5-year limb salvage rate as determined by Kaplan-Meier analysis was 89 percent. CONCLUSIONS: The use of free tissue transplantation for treatment of foot and ankle wounds is associated with a high rate of limb salvage. Although a variety of flaps may be used, the application of the subunit principle can assist surgeons in designing flaps that will address subunit-specific functional and aesthetic concerns.