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Background: This study investigated the effect of mesenchymal stem cell implantation on flexor tendon healing using a rabbit model of flexor tendon repair. Specifically, we compared the difference between autologous and allogeneic stem cells. The influence of cell number on the outcome of flexor tendon healing was also investigated.

Methods: Repaired tendons on the rear paws of rabbits were randomly assigned into four groups: control group, 1 million autologous cells, 1 million allogeneic cells, and 4 million allogeneic cells. Rabbits were sacrificed at 3 or 8 weeks after surgery.

Results: Implantation of 4 million stem cells resulted in a significant increase in range of motion compared with control group at three weeks after surgery. The positive staining of collagen I in healing tendons was enhanced in stem cell treated groups three weeks after surgery. However, stem cells did not improve biomechanical properties of flexor tendons.

Conclusions: High dose stem cells attenuated adhesions in the early time point following flexor tendon repair. Further work is needed determine the value of stem cell therapy in flexor tendon healing in humans.

Background: Although flexor tendon injuries cause significant morbidities and socio-economic implications, there have been limited data on patient demographics, injury characteristics and surgical details. The aim of this study is to describe our experience in flexor tendon injuries and repairs.

Methods: We performed a retrospective study of all digital flexor tendon injuries that were repaired from January 2011 to December 2014. The collected data included patient demographics, injury characteristics and surgical details.

Results: A total of 214 patients, 308 digits with 446 flexor tendon repairs were identified. We found that males, non-residents, and 20–29 age group were most prone to flexor tendon injuries. Cleaners, labourers and related occupations were the most vulnerable. The mechanism of injury was usually work-related and mostly caused by glass. Most injuries involve both flexor digitorum profundus and flexor digitorum superficialis tendons. Concomitant digital nerve and vessel injuries were common. Most patients suffered zone 2 laceration of a single digit of the non-dominant hand. Most patients underwent procedures that lasted 1 to 2 hours, including multiple flexor tendon repairs, microsurgical repairs and other interventions.

Conclusions: This study is the largest study on patient demographics, injury characteristics and surgical details on flexor tendon injuries and repairs. It could be used to plan resources and policies for the management and prevention of flexor tendon injuries.

Background: Flexor tendon rehabilitation protocols minimize repair tension by limiting range of movement to prevent tendon rupture. The resultant muscle contracture inhibits finger extension, increases resistance in tendon gliding distally, and progress to proximal interphalangeal (PIP) joint flexion contracture. This study describes our new rehabilitation protocol, the Tension Reducing Muscle Stretch (TRMS), designed to prevent flexor muscle contracture and obtain full distal tendon excursion.

Methods: We reviewed retrospectively 14 fingers in 13 consecutive patients with primary repair of complete zone I or II flexor digitorum profundus (FDP) tendon rupture were treated with our protocol between 2007 and 2019. Our rehabilitation following FDP 4-strand repairs consisted of three steps. The first step comprised of exercises from traditional protocols such as Duran, Kleinert, Synergistic-wrist-motion, and Place-and-hold. The second step comprised the TRMS exercise to prevent the onset of muscle contracture. Anatomically, FDP tendons arise from the same FDP muscle belly. TRMS involved placing the affected finger in full passive flexion while unaffected fingers were passively extended to full extension. This made the affected FDP muscle stretched. The final step incorporated the early active flexion motion exercise, in which simple fisting was performed, from a fully extended position.

Results: The mean total active motion at the final follow up was 235° (range 170–265). Using the Strickland criteria, eight achieved excellent, four had good, two had fair results. The mean angle of passive extension deficit at the PIP joint at four weeks after surgery was −7° (−30–0), and at the final follow up was −3° (−20–0). No tendon repair was ruptured.

Conclusions: This protocol reduced tension in the affected tendon muscle and encouraged tendon excursion distal to the repair site without complications. It allows full tendon excursion and prevents PIP joint contractures.

Closed rupture of the flexor digitorum profundus (FDP) tendon causes loss of flexion at the distal interphalangeal joint. Following trauma, these are known to present as avulsion fractures (Jersey finger) commonly in ring fingers. Traumatic tendon ruptures at the other flexor zones are seldom noted and are often missed. In this report, we present a rare case of closed traumatic tendon rupture of the long finger FDP at zone 2. Though it was missed initially, was confirmed with Magnetic Resonance Imaging and underwent successful reconstruction using an ipsilateral palmaris longus graft.

Level of Evidence: Level V (Therapeutic)