Shin, Alexander Y.

Background: The addition of adipose-derived mesenchymal stromal cells to decellularized nerve allografts may improve outcomes of nerve reconstruction. Prior techniques used for cell seeding are traumatic to both the mesenchymal stromal cells and nerve graft. An adequate, reliable, and validated cell seeding technique is an essential step for evaluating the translational utility of mesenchymal stromal cell–enhanced decellularized nerve grafts. The purpose of this study was to develop a simple seeding strategy with an optimal seeding duration. Methods: A dynamic bioreactor was used to seed rat and human mesenchymal stromal cells separately onto rat and human decellularized nerve allografts. Cell viability was evaluated by MTS assays and cellular topology after seeding was determined by scanning electron microscopy. Cell density and distribution were determined by Live/Dead assays and Hoechst staining at four different time points (6, 12, 24, and 72 hours). The validity and reliability of the seeding method were calculated. Results: Cells remained viable at all time points, and mesenchymal stromal cells exhibited exponential growth in the first 12 hours of seeding. Seeding efficiency increased significantly from 79.5 percent at 6 hours to 89.2 percent after 12 hours of seeding (p = 0.004). Both intrarater reliability (r = 0.97) and interrater reliability (r = 0.92) of the technique were high. Conclusions: This study describes and validates a new method of effectively seeding decellularized nerve allografts with mesenchymal stromal cells. This method is reproducible, distributes cells homogenously over the graft, and does not traumatize the intraneural architecture of the allograft. Use of this validated seeding technique will permit critical comparison of graft outcomes.

Background: Trapeziectomy with ligament reconstruction tendon interposition (LRTI) or suspensionplasty is an effective treatment in older patients with end-stage thumb basilar arthritis. However, the survivability of this procedure is unknown in younger patients who may impart more stress on their thumbs. Methods: A retrospective review was performed on all patients who underwent trapeziectomy and LRTI or suspensionplasty at 55 years of age or younger from 1992 to 2008. Objective clinical outcome measures included preoperative to postoperative changes in thumb range of motion, grip and pinch strength, a study-specific thumb function score, and the Buck-Gramcko subjective outcome score. Progressive metacarpal subsidence was evaluated on radiographs. Survivorship free from revision surgery was calculated with a Kaplan-Meier analysis. Results: A total of 57 wrists underwent trapeziectomy and LRTI (n = 18) or suspensionplasty (n = 39). The mean patient age at the time of surgery was 49.6 years (range: 38-55 years). Mean clinical and radiographic follow-up were 10.2 and 6.4 years, respectively. Overall, there were significant improvements in pain and grip strength despite progressive and metacarpal subsidence. Survivorship was 100% and 86% free from revision surgery at 10 and 15 years, respectively (n = 2 failures). Conclusions: Trapeziectomy and LRTI or suspensionplasty in patients less than or equal to 55 years of age can result in considerable improvements in pain and grip strength with a 10-year survivorship free from revision.

Axial carpal injuries are rare entities where a traumatic force transmits through the intermetacarpal space, dissociating the carpometacarpal joint and disrupting the distal carpal row in an axial radial or axial ulnar pattern via true axial force or compressive crush mechanism. Differences in outcomes remain unclear with regard to the specific type of axial carpal injury pattern. A retrospective case series identified 37 wrists (in 37 patients) over 25 years who presented to a Level 1 trauma centre, with 20 wrists experiencing an axial radial injury and 17 wrists experiencing an axial ulnar injury. Of all the variables evaluated, only axial radial injuries were identified as predictors of poor outcome as defined by Mayo Wrist scores with univariate analysis demonstrating 6 times increased risk and multivariate analysis demonstrating 15 times increased risk of a poor outcome compared with axial ulnar injuries. This knowledge will provide prognostic information to surgeons managing patients with these severe injuries. Level of evidence: IV

IntroductionIn prior small animal studies, we maintained vascularized bone allotransplant viability without long‐term immunotherapy. Instead, an autogenous neoangiogenic circulation is created from implanted vessels, sufficient to maintain bone viability with only 2 weeks immunosupression. Blood flow is maintained despite rejection of the allogeneic vascular pedicle thereafter. We have previously described a large animal (swine) pre‐clinical model, reconstructing tibial defects with vascularized tibial allotransplants. In this manuscript, autologous angiogenesis is evaluated in this model and correlated with bone viability.Materials and methodsAllogeneic tibial segments were transplanted across a major swine leukocyte antigen mismatch. Microvascular repair of the bone VCA pedicle was combined with intraosseous implantation of an autogenous arteriovenous (AV) bundle. The bundle was ligated in group 1 (n = 4), and allowed to perfuse in group 2 (n = 4). Three‐drug immunotherapy was given for 2 weeks. At 16 weeks micro‐CT angiography quantified neoangiogenic vessel volume. Bone viability, rejection grade, and bone healing were analyzed.ResultsA substantial neoangiogenic circulation developed from the implanted AV‐bundle in group 2, with vessel density superior to ligated AV‐bundle controls (0.11 ± 0.05 vs. 0.01 ± 0.01, P = .029). Bone allotransplant viability was also significantly enhanced by neoangiogenesis (78.7 ± 4.4% vs. 27.7 ± 5.8%, P = .028) with higher bone healing scores (21.4 ± 2.9 vs. 12.5 ± 3.7, P = .029). Ligated control tibias demonstrated disorganized bone morphology and higher local inflammation (P = .143).ConclusionImplantation of autogenous AV bundles into vascularized bone allotransplants resulted in the rapid formation of a neoangiogenic autogenous blood supply in a swine tibia model that maintained bone viability, improved bone healing, and minimized rejection.

We studied 57 patients with isolated lunotriquetral injuries treated by arthrodesis, direct ligament repair, or ligament reconstruction. The outcomes were compared by using written questionnaires, the Disabilities of the Arm, Shoulder and Hand (DASH) score, range of movement, strength, morbidity and rates of reoperation. Isolated lunotriquetral injury was confirmed by arthroscopy or arthrotomy. The mean age of the patients was 30.7 years (15.4 to 53.7) and the injuries were subacute or chronic in 98.2%. Eight patients underwent lunotriquetral reconstruction using a distally-based strip of the tendon of extensor carpi ulnaris, 27 had lunotriquetral repair and 22 had lunotriquetral arthrodesis. The mean follow-up was 9.5 years (2 to 22). The probability of remaining free from complications at five years was 68.6% for reconstruction, 13.5% for repair, and less than 1% for arthrodesis. Of the lunotriquetral arthrodeses, 40.9% developed nonunion and 22.7% developed ulnocarpal impaction. The probability of not requiring further surgery at five years was 68.6% for reconstruction, 23.3% for repair and 21.8% for arthrodesis. The DASH scores for each group were not significantly different. Objective improvements in strength and movement, subjective indicators of pain relief and satisfaction were significantly higher in the lunotriquetral repair and reconstruction groups than in those undergoing arthrodesis.

OBJECTIVEReconstructive options for brachial plexus lesions continue to expand and improve. The purpose of this study was to evaluate the prevalence and quality of restored elbow extension in patients with brachial plexus injuries who underwent transfer of the spinal accessory nerve to the motor branch of the radial nerve to the long head of the triceps muscle with an intervening autologous nerve graft and to identify patient and injury factors that influence functional triceps outcome.METHODSA total of 42 patients were included in this retrospective review. All patients underwent transfer of the spinal accessory nerve to the motor branch of the radial nerve to the long head of the triceps muscle as part of their reconstruction plan after brachial plexus injury. The primary outcome was elbow extension strength according to the modified Medical Research Council muscle grading scale, and signs of triceps muscle recovery were recorded using electromyography.RESULTSWhen evaluating the entire study population (follow-up range 12–45 months, mean 24.3 months), 52.4% of patients achieved meaningful recovery. More specifically, 45.2% reached Grade 0 or 1 recovery, 19.1% obtained Grade 2, and 35.7% improved to Grade 3 or better. The presence of a vascular injury impaired functional outcome. In the subgroup with a minimum follow-up of 20 months (n = 26), meaningful recovery was obtained by 69.5%. In this subgroup, 7.7% had no recovery (Grade 0), 19.2% had recovery to Grade 1, and 23.1% had recovery to Grade 2. Grade 3 or better was reached by 50% of patients, of whom 34.5% obtained Grade 4 elbow extension.CONCLUSIONSTransfer of the spinal accessory nerve to the radial nerve branch to the long head of the triceps muscle with an interposition nerve graft is an adequate option for restoration of elbow extension, despite the relatively long time required for reinnervation. The presence of vascular injury impairs functional recovery of the triceps muscle, and the use of shorter nerve grafts is recommended when and if possible.

IntroductionVascularized bone allotransplantation may provide new options for reconstruction of segmental defects if problems of long‐term immune modulation can be solved. The current literature lacks an orthotopic large animal model, limited to bone and without the confounding effects of other tissue types, permitting a multifaceted evaluation before new methods are used clinically. The purpose of this study was to develop a large animal model for vascularized bone allotransplantation.Materials and methodsEight porcine hind limbs were dissected. Length, diameter, and location of all hindlimb vessels were measured and a single nutrient vessel supplying the tibial diaphysis identified enabling its use as a vascularized bone allotransplant. Four Yucatan minipigs were divided into two pairs with a major swine leukocyte antigen mismatch. A 3.5 cm tibial segment including its nutrient pedicle was raised simultaneously from each pig and transplanted into the matched defect of the other animal. Microarterial anastomosis of the pedicle and 3‐drug immunosuppression maintained VCA viability. Bone healing and limb function were followed for 16 weeks.ResultsA consistent tibia diaphyseal nutrient artery arose from the caudal tibial artery to enter bone a mean 2.8 mm distal to the tibial tubercle with a pedicle length of 6.6 ± 3.3 mm and diameter of 1.6 ± 0.2 mm. Using this pedicle, we reconstructed a 3.5 cm tibial defect with a vascularized bone allotransplant in four animals. Immediate weightbearing as well as progressive bone healing was demonstrated.ConclusionWe have developed a vascularized tibial bone allotranplantation large‐animal model suitable for future bone‐only allotranplantation research in mini‐pigs.

Background: Nonvascularized bone grafting (NVBG) and vascularized bone grafts (VBGs) have been used to treat scaphoid nonunions. A comparison of a single institution’ s experience using structural iliac crest bone graft (ICBG), 1,2-intercompartmental supraretinacular artery (1,2-ICSRA), and medial femoral condyle (MFC) grafts to treat scaphoid nonunions was undertaken. Methods: Thirty-one patients underwent ICBG, 33 patients underwent 1,2-ICSRA, and 45 patients underwent MFC grafting. Mean time to follow-up was 16 months (range, 2-153). Twenty-three percent used tobacco products. Mean age was 24 years (range, 11-66), with 86% male patients. Outcomes included union rate, time to healing, range of motion, complications, and reoperations. Results: Union rates and mean time to union were 71% and 19 weeks for the ICBG group, 79% and 26 weeks for the 1,2-ICSRA group, and 89% and 16 weeks for the MFC group, respectively. Failure of union was associated with tobacco use but not with age, gender, time from injury to surgery, or type of fixation. There was no significant difference between the groups regarding range of motion or strength. Conclusions: These findings demonstrate the need for careful patient selection. In patients with the most complicated scaphoid nonunions (avascular necrosis, carpal collapse, and previous surgeries), the MFC group had the highest union rate and fastest time to union. Patients with risk factors for failure should be counseled on the outcomes and possible need for salvage fusion surgery.

* Preclinical animal studies have demonstrated that vascularized bone grafts increase blood flow, maintain patent pedicles, provide immediate structural integrity, hypertrophy in response to mechanical stress, and deliver proper environments for healing in challenging situations. * The absolute indications for vascularized bone graft as borne out by high-quality studies have yet to be defined. Currently, the literature suggests varying success rates for difficult reconstructive problems requiring additional biological and structural properties offered only by vascularized bone-grafting. * Orthopaedic reconstructive challenges can be met with a variety of options, including pedicled and free vascularized bone grafts.