In vivo model of human post-traumatic heterotopic ossification demonstrates early fibroproliferative signature.

BACKGROUND: The relationship between the tissue injury healing response and development of heterotopic ossification (HO) is poorly understood. Here we compare a rat blast model and human traumatized muscle from a blast injury to study the early signatures of osteogenesis and fibrosis during the formation of HO. METHODS: Rat and human tissues were characterized using histology, scanning electron microscopy, immunohistochemistry, as well as gene and protein expression analysis. Additionally, animals and humans were assessed radiographically for HO formation following injury. RESULTS: Markers of bone formation were dramatically increased in tissue samples from both humans and rats, and both displayed increased fibroproliferative regions within the injured tissues and elevated expression of markers of tissue fibrosis such as TGF-ß1, Fibronectin, SMAD3 and PAI-1. Markers of inflammation and fibrosis (ACTA, TNFα, BMP1 and BMP3) were elevated at the RNA level in both rat and human samples. By day 42, bone formation in the rat blast model appeared similar in radiographs compared to human patients who progressed to develop post-traumatic HO. CONCLUSIONS: Our data demonstrates that a similar early fibrotic response is evident in both the rat blast model and the human tissues following a traumatic injury and demonstrates the relevance of this animal model for future translational studies.

Hook Plate Versus Suture Anchor Fixation for Thumb Ulnar Collateral Ligament Fracture-Avulsions: A Cadaver Study.

PURPOSE: To compare the biomechanical properties of hook plate fixation and suture anchor fixation for collateral ligament fracture-avulsions of the thumb metacarpophalangeal ulnar collateral ligament (UCL). METHODS: A thumb UCL fracture-avulsion model was created in 7 matched pairs of cadaver hands. An osteotomy was made parallel to the shaft of the proximal phalanx along the entire insertion of the UCL. The simulated fracture was secured using either a suture anchor tied over bone tunnels in the avulsion fragment or with a hook plate. Specimens were mounted on a servohydraulic load frame and loaded to failure. Motion perpendicular to the osteotomy was measured using an implanted 3-mm differential variable reluctance transducer device. Differences in load to failure and construct stiffness were compared and analyzed using a t test. RESULTS: The hook plate construct failed at significantly higher loads than suture fixation. Mean load to failure in the hook plate construct was 58 N (± 20 N) compared with 27 N (± 19 N) in the suture anchor construct. The difference in construct stiffness was 49 N/mm (± 17 N/mm) for the plate compared with 7 N/mm (± 13 N/mm) for the suture anchor. The main mechanism of failure for the hook plate construct was screw pullout or screw bending. The usual mechanism of failure for the suture anchor construct was anchor pullout. CONCLUSIONS: The hook plate construct was biomechanically superior to the suture anchor construct for fixation of thumb metacarpophalangeal joint UCL fracture-avulsions with regard to load to failure. CLINICAL RELEVANCE: The hook plate construct provides stronger fixation than a suture anchor for thumb UCL fracture-avulsions.

Quality of healing: defining, quantifying, and enhancing skeletal muscle healing.

Skeletal muscle injury is common in everyday physical activity and athletics, as well as in orthopedic trauma and disease. The overall functional disability resulting from muscle injury is directly related to the intrinsic healing properties of muscle and extrinsic treatment options designed to maximize repair and/or regeneration of muscle tissue all while minimizing pathologic healing pathways. It is important to understand the injury and repair pathways in order to improve the speed and quality of recovery. Recent military conflicts in Iraq and Afghanistan have highlighted the importance of successfully addressing muscular injury and showed the need for novel treatment options that will maximize functional regeneration of the damaged tissue. These severe, wartime injuries, when juxtaposed to peacetime, sports-related injuries, provide us with interesting case examples of the two extreme forms of muscular damage. Comparing and contrasting the differences in these healing pathways will likely provide helpful cues that will help physicians recapitulate the near complete repair and regeneration in less traumatic injuries in addition to more severe cases.

Resilience and Patient-Reported Outcomes in Patients Undergoing Orthopedic Hand Surgery.

BACKGROUND: Previous studies have examined the impact of resiliency on postoperative outcomes in other orthopedic domains, but none to date have done so for hand surgery. METHODS: We performed a retrospective analysis of prospectively collected data of patients undergoing hand surgery at a single institution. We included patients with complete preoperative outcomes scores and 6-month follow-up. All patients completed the Brief Resilience Scale (BRS), Disabilities of the Arm, Shoulder, and Hand (DASH) Score, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH), Veterans RAND 12-Item Health Survey (VR-12), and Numeric Rating Scale (NRS) for pain. Patients were stratified into high-resiliency (HR) and low-resiliency (LR) groups based on the preoperative BRS score, and outcomes between groups were compared. RESULTS: We identified 91 patients who underwent hand procedures and completed full preoperative and postoperative outcomes measures. There were no observed preoperative differences between the groups in all outcomes scores except the VR-12 Mental Component Score. Postoperatively, the HR group had superior DASH, QuickDASH, and VR-12 (mental and physical component) scores than the LR group. Postoperative pain, as measured by the NRS, was significantly lower in the HR group despite there being no preoperative difference. A larger percentage of patients in the HR group met the minimal clinically important difference in all outcomes except for the VR-12 Mental Component Scores. CONCLUSIONS: Patients with high preoperative resilience appear to have significantly better clinical outcomes following hand surgery with superior DASH, QuickDASH, and VR-12 scores at 6-month follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic study/Level IV evidence.

Successful Closed Reduction of Distal Radius Volar Locking Plate Plastic Deformation with Associated Fracture: A Case Report.

CASE: Distal radius fractures are among the most common orthopaedic injuries. The volar locking plate is now the most utilized internal fixation method for these fractures. There are few reports of mechanical failure of volar locking plates within the literature. In this case report, we describe successful closed reduction of traumatic volar locking plate plastic deformation with associated fracture. In addition, we discuss existing literature regarding plastic deformation of distal radius plates. CONCLUSION: Traumatic, plastic deformation of distal radius volar locking plates with associated fracture may be managed nonoperatively with closed reduction.

Medial Femoral Condyle Vascularized Bone Graft for Treatment of Midshaft Clavicle Recalcitrant Nonunion With Use of the Transverse Cervical Artery as an Anastomosis.

Vascularized medial femoral condyle bone grafts have been reported to be a reliable treatment for recalcitrant bony nonunions of the extremities. Although clavicle fracture nonunions are rare after treatment with open reduction internal fixation, symptomatic nonunions can be a challenge. The medial femoral condyle vascularized bone graft has been described as a treatment option for clavicle nonunions with the thoracoacromial trunk as the recipient anastomosis site. This case illustrates how the transverse cervical artery and accompanying veins can be used as an anastomosis when the thoracoacromial trunk is inaccessible because of previous surgical- and infection-related scaring. At the final follow-up, the patient had returned to full duty and resumed competitive triathlons. Radiographs demonstrated complete healing of clavicle fracture.

Management of Iatrogenic Nerve Injuries.

Iatrogenic peripheral nerve injuries from orthopaedic surgery can occur via many scenarios, including direct injury to the nerve during surgery, indirect injury via retraction or compartment syndrome, and injury from nonsurgical treatments such as injections and splinting. Successful management of iatrogenic nerve injuries requires an accurate diagnosis and timely, appropriate treatment. All orthopaedic surgeons must understand the preclinical study of nerve injury and the evaluation and treatment options for iatrogenic nerve injuries. Although a sharply transected nerve can be repaired immediately in the operating room under direct visualization, many injuries are not appreciated until the postoperative period. Advances in diagnostic studies and nerve repair techniques, nerve grafting, and nerve transfers have improved our ability to identify and treat such injuries.

Ballistic trauma: lessons learned from iraq and afghanistan.

Management of upper extremity injuries secondary to ballistic and blast trauma can lead to challenging problems for the reconstructive surgeon. Given the recent conflicts in Iraq and Afghanistan, advancements in combat-casualty care, combined with a high-volume experience in the treatment of ballistic injuries, has led to continued advancements in the treatment of the severely injured upper extremity. There are several lessons learned that are translatable to civilian trauma centers and future conflicts. In this article, the authors provide an overview of the physics of ballistic injuries and principles in the management of such injuries through experience gained from military involvement in Iraq and Afghanistan.

Fibroregulation of mesenchymal progenitor cells by BMP-4 after traumatic muscle injury.

OBJECTIVES: Traumatized muscle is a complex healing environment containing cells with robust reparative and regenerative potential interacting in a cytokine milieu that influences the function and differentiation of these cells, leading to a spectrum of healing responses. In particular, bone morphogenetic protein-4 (BMP-4) is of interest as a potential modulator of healing because its dysregulation has been associated with fibrosis and heterotopic ossification formation. We propose a descriptive study of altered BMP-4 expression in traumatized muscle tissue and to evaluate its role in the fibroregulatory function of resident mesenchymal progenitor cells (MPCs) at the protein- and gene-expression levels. METHODS: Protein-level expression of BMP-4 from cells resident in traumatized muscle specimens was evaluated using ELISA and also using sodium dodecyl sulfate-polyacrylamide gel electrophoresis to compare BMP-4 in homogenized muscle tissue specimens. BMP-4, cartilage oligomeric matrix protein (COMP), and osteocalcin expression localization was analyzed via immunohistochemistry. Reverse transcription-polymerase chain reaction was performed to evaluate fibroregulatory gene expression in MPCs after treatment with BMP-4. RESULTS: BMP-4 was present in all traumatized muscle tissue specimens. Immunohistochemistry demonstrated that traumatized muscle fibers contained greater number of cells expressing BMP-4 in a more disorganized fashion compared with control samples. Reverse transcription-polymerase chain reaction demonstrated that COMP, growth and differentiation factor-10, and integrin beta-2 were up-regulated, whereas tumor necrosis factor-alpha was significantly down-regulated. COMP expression was colocalized in the traumatized muscle tissue with osteocalcin. CONCLUSIONS: BMP-4 has an effect on MPCs that seems to promote fibrotic tissue formation. These findings suggest that BMP-4, while promoting osteoinduction, may also act on MPCs to promote formation of a fibrotic osteoinductive matrix. Thus, this signaling axis might be a potential target for heterotopic ossification prevention.