Moran, Steven L.

Background: Flexor digitorum profundus (FDP) tendon injury is common in hand trauma, and flexor tendon reconstruction is one of the most challenging procedures in hand surgery because of severe adhesion that exceeds 25% and hinders hand function. The surface properties of a graft from extrasynovial tendons are inferior to those of the native intrasynovial FDP tendons, which has been reported as one of the major causations. Improved surface gliding ability of the extrasynovial graft is needed. Thus, this study used carbodiimide-derivatized synovial fluid and gelatin (cd-SF-gel) to modify the surface of the graft, thus improving functional outcomes using a dog in vivo model. Methods: Forty FDP tendons from the second and fifth digits of 20 adult women underwent reconstruction with a peroneus longus (PL) autograft after creation of a tendon repair failure model for 6 weeks. Graft tendons were either coated with cd-SF-gel (n = 20) or not. Animals were euthanized 24 weeks after reconstruction, and digits were collected after the animals were euthanized for biomechanical and histologic analyses. Results: Adhesion score (cd-SF-gel, 3.15 ± 1.53; control, 5 ± 1.26; P < 0.00017), normalized work of flexion (cd-SF-gel, 0.47 ± 0.28 N-mm/degree; control, 1.4 ± 1.45 N-mm/degree; P < 0.014), and distal interphalangeal joint motion (cd-SF-gel, 17.63 ± 6.77 degrees; control, 7.07 ± 12.99 degrees; P < 0.0015) in treated grafts all showed significant differences compared with nontreated grafts. However, there was no significant difference in repair conjunction strength between the two groups. Conclusion: Autograft tendon surface modification with cd-SF-gel improves tendon gliding ability, reduces adhesion formation, and enhances digit function without interfering with graft-host healing. Clinical Relevance Statement: The authors demonstrate a clinically relevant and translational technology by using the patient’s own synovial fluid to “synovialize” an autologous extrasynovial tendon graft to improve functional outcomes following flexor tendon reconstruction.

Background: Nerve injuries can result in detrimental functional outcomes. Currently, autologous nerve graft offers the best outcome for segmental peripheral nerve injury. Allografts are alternatives, but do not have comparable results. This study evaluated whether plasma-derived exosome can improve nerve regeneration and functional recovery when combined with decellularized nerve allografts. Methods: The effect of exosomes on Schwann cell proliferation and migration were evaluated. A rat model of sciatic nerve repair was used to evaluate the effect on nerve regeneration and functional recovery. A fibrin sealant was used as the scaffold for exosome. Eighty-four Lewis rats were divided into autograft, allograft, and allograft with exosome groups. Gene expression of nerve regeneration factors was analyzed on postoperative day 7. At 12 and 16 weeks, rats were subjected to maximum isometric tetanic force and compound muscle action potential. Nerve specimens were then analyzed by means of histology and immunohistochemistry. Results: Exosomes were readily taken up by Schwann cells that resulted in improved Schwann cell viability and migration. The treated allograft group had functional recovery (compound muscle action potential, isometric tetanic force) comparable to that of the autograft group. Similar results were observed in gene expression analysis of nerve regenerating factors. Histologic analysis showed no statistically significant differences between treated allograft and autograft groups in terms of axonal density, fascicular area, and myelin sheath thickness. Conclusions: Plasma-derived exosome treatment of decellularized nerve allograft may provide comparable clinical outcomes to that of an autograft. This can be a promising strategy in the future as an alternative for segmental peripheral nerve repair. Clinical Relevance Statement: Off-the-shelf exosomes may improve recovery in nerve allografts.

(1) Background: Resection of soft-tissue sarcomas (STS) of the upper extremity can result in substantial functional impairment with limited options for functional reconstruction. Free functional latissimus flaps have been utilized to restore function of the thigh; however, there is limited data on the use of latissimus flaps for functional reconstruction in the upper extremity. As such, we sought to evaluate our institutional experience with these flaps. (2) Methods: We reviewed ten (seven male; three female; and a mean age of 63 years) patients undergoing soft-tissue sarcoma resection involving the triceps (n = 4), biceps (n = 4), and deltoid (n = 2) reconstructed with a pedicled functional latissimus flap. All surviving patients had at least 1 year of follow-up, with a mean follow-up of 5 years. (3) Results: The mean elbow range of motion and shoulder elevation were 105° and 150°. The mean Musculoskeletal Tumor Society score was 88%, and the muscle strength was four. Four patients had a recipient site wound complication. There were no flap losses. One patient sustained a radiation-associated humerus fracture 5 years postoperatively, treated nonoperatively. (4) Conclusions: Although early complications are high, pedicled functional latissimus flaps allow for wound coverage, potential space obliteration, and restoration of function in the upper extremity following resection of large soft tissue sarcomas.

Abstract Background In predynamic or dynamic scapholunate (SL) instability, standard diagnostic imaging may not identify SL interosseous ligament (SLIL) injury, leading to delayed detection and intervention. This study describes the use of four-dimensional computed tomography (4DCT) in identifying early SLIL injury and following injured wrists to 1-year postoperatively. Description of Technique 4DCT acquires a series of three-dimensional volume data with high temporal resolution (66 ms). 4DCT-derived arthrokinematic data can be used as biomarkers of ligament integrity. Patients and Methods This study presents the use of 4DCT in a two-participant case series to assess changes in arthrokinematics following unilateral SLIL injury preoperatively and 1-year postoperatively. Patients were treated with volar ligament repair with volar capsulodesis and arthroscopic dorsal capsulodesis. Arthrokinematics were compared between uninjured, preoperative injured, and postoperative injured (repaired) wrists. Results 4DCT detected changes in interosseous distances during flexion-extension and radioulnar deviation. Generally, radioscaphoid joint distances were greatest in the uninjured wrist during flexion-extension and radioulnar deviation, and SL interval distances were smallest in the uninjured wrist during flexion-extension and radioulnar deviation. Conclusion 4DCT provides insight into carpal arthrokinematics during motion. Distances between the radioscaphoid joint and SL interval can be displayed as proximity maps or as simplified descriptive statistics to facilitate comparisons between wrists and time points. These data offer insight into areas of concern for decreased interosseous distance and increased intercarpal diastasis. This method may allow surgeons to assess whether (1) injury can be visualized during motion, (2) surgery repaired the injury, and (3) surgery restored normal carpal motion. Level of Evidence Level IV, Case series.

Background: Early soft-tissue reconstruction of open fractures has been shown to decrease infection rates and improve rates of bony union. The purpose of this study was to compare the rates and time to union of open tibia fractures that underwent soft-tissue coverage. Methods: A retrospective chart review of 118 patients with open tibia fractures requiring soft-tissue reconstruction treated at a single level 1 trauma center was performed. Demographic data as well as flap type were collected. Union status was determined using modified Radiographic Union Scale in Tibia Fractures score greater than 11. Results: Limb salvage was achieved in 90% of patients. The overall rate of nonunion was 33%. Flap type significantly affected time to union, with local fasciocutaneous and keystone flaps having significantly longer time to union [202 days (SD 120.3)] than all other flap groups (P = 0.01). Free flaps had significantly shorter time to union than local flaps [115 days (SD 49.6) versus 149 days (SD 75.4); P = 0.02]. Muscle flaps had significantly shorter time to union than fasciocutaneous flaps [123 days (SD 52.4) versus 165 days (SD 104.1); P = 0.04]. This remained true after controlling for fracture location, patient age, need for second flap, and fixation method (P = 0.037). Patients who underwent an initial soft-tissue reconstruction with a local muscle flap were more likely to require a second flap to achieve wound closure (OR, 3.7; P = 0.008) and needing a second flap significantly increased time to union [162 days (SD 95.9) versus 122 days (SD 51.9); P = 0.03]. Conclusion: Flap type affects time to union but not nonunion rate in open tibia fractures. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Background: Congenital clasped thumb is associated with deficient thumb extensor tendons. Reconstruction includes tendon transfer. Here, we describe a variant of the abductor pollicis longus (APL) tendon, not previously reported, contributing to the flexion deformity. The purpose of this study is to report examples of and offer surgical repair techniques for APL variants identified in patients with clasped thumb. Methods: We reviewed records of 11 consecutive patients undergoing reconstruction for clasped thumb. Surgical anatomy of the APL tendon was evaluated in all patients, followed by release of aberrant APL attachments. Participants were invited to return for an in-person assessment with a certified hand therapist. Data were collected regarding intraoperative findings, surgical techniques for reconstruction, postoperative thumb motion, and patient and caregiver satisfaction. Results: Eleven children (12 thumbs) underwent aberrant APL release and rerouting between 2019 and 2021. Preoperatively, all thumbs were passively correctible to 0° of extension. In all patients, the APL was found to terminate palmar to the metacarpophalangeal (MCP) joint, creating an MCP flexion moment when tensioned. The average age at surgery was 7 years (range: 1-15 years), and the average follow-up was 14.2 months (range: 1-21 months). The mean postoperative thumb radial abduction was 55° (range: 20°-75°). Conclusions: When reconstructing clasped thumbs, surgeons should explore the presence of APL abnormalities. Release and centralization of the APL can improve thumb position and function. This technique may avoid the need for extra-anatomical tendon transfer in patients with clasped thumb.

Objectives: Peripheral arterial disease is a significant cause of morbidity and mortality. The goal of this study was to develop a novel treatment to promote angiogenesis. Platelets have been previously implicated in angiogenic events; however, platelet activation rather than presence of growth factors has been associated with new blood vessel formation. This study evaluated exosomes purified from activated platelets to determine their potential in promoting angiogenesis both in vitro and in vivo. Methods & Results: Under Current Good Manufacturing Practices, conditioned medium processed from apheresis platelet cultures yielded a purified exosome product (PEP) enriched for CD63, CD9 and Alix. In vitro, PEP drove HUVEC proliferation, migration, and vascular tube formation. Proteomic evaluation showed Flk1 (VEGFR2) was one of the key angiogenic proteins in PEP. HUVECs treated with Flk1 antibody neutralized PEP (anti-Flk1-PEP) showed reduced vascular tube formation compared to PEP. To evaluate in vivo angiogenesis, a rodent model of hindlimb ischemia was treated with sustained release PEP embedded in fibrin glue (PEP/TISSEEL) with blood flow evaluated by SPY angiography at 28 days post-treatment. Animals treated with PEP/TISSEEL showed improved blood flow with significant difference (p<0.001) as compared to sham, TISSEEL, and anti-Flk1-PEP/TISSEEL. Muscle tissue stained with α smooth muscle actin showed a significant increase (p<0.001) in vascular area in PEP/TISSEEL treated animals compared to TISSEEL alone. To further evaluate clinical translatability, a rabbit ear ischemia wound model was then treated with PEP/TISSEEL. Rabbit ears showed accelerated wound healing and restored blood flow on SPY angiography. Histologic evaluation of vascular area showed a significant increase in vascular area (p<0.05) compared to sham and TISSEEL alone animals. Conclusions: Exosome driven donation of Flk1 here promoted angiogenic events and was successfully translated into healing outcomes in the setting of two animal models of peripheral ischemia. This novel insight into biotherapy achievable pro-angiogenesis establishes a clinical-grade off-the-shelf exosome technology for the treatment of peripheral vascular disease.

Abstract Background Scapholunate (SL) ligament injuries are rarely diagnosed in children. This study reports the outcomes of surgically treated SL ligament injuries in patients younger than 18 years. Methods A retrospective review was performed on 20 pediatric patients with SL ligament injuries. Records were reviewed for preoperative and postoperative radiographic data, intraoperative findings, classifications of interosseous ligament injury, and postoperative course. Results Thirteen girls and seven boys sustained SL injuries requiring operative intervention and were followed for an average of 26 months. Magnetic resonance imaging (MRI) was performed in 15 patients, which revealed an SL tear in 7 patients. Arthroscopically, SL injuries were classified as Geissler grade III in 12 patients and grade IV in 5 patients. Based on the Mayo Wrist Score, nine patients had excellent or good results, while six demonstrated fair results. The mean wrist flexion–extension arc was 109 degrees, while the mean grip strength was 82% of the unaffected side. Patients treated >1 year following injury had significantly decreased grip strength and Mayo Wrist Score. Conclusion In this study, worse results were seen in children with a protracted course prior to treatment of an SL injury. A high index of suspicion is necessary to detect an SL injury in the younger age group and should be in the differential for those with persistent dorsal wrist pain, tenderness over the dorsal SL joint, and/or positive Watson's test. MRI may assist in diagnosis but is not definitive to rule out injury. Arthroscopy is valuable to determine the extent of injury.