Myeloid Cells and Sensory Nerves Mediate Peritendinous Adhesion Formation via Prostaglandin E2.

Peritendinous adhesion that forms after tendon injury substantially limits daily life. The pathology of adhesion involves inflammation and the associated proliferation. However, the current studies on this condition are lacking, previous studies reveal that cyclooxygenase-2 (COX2) gene inhibitors have anti-adhesion effects through reducing prostaglandin E2 (PGE2) and the proliferation of fibroblasts, are contrary to the failure in anti-adhesion through deletion of EP4 (prostaglandin E receptor 4) gene in fibroblasts in mice of another study. In this study, single-cell RNA sequencing analysis of human and mouse specimens are combined with eight types of conditional knockout mice and further reveal that deletion of COX2 in myeloid cells and deletion of EP4 gene in sensory nerves decrease adhesion and impair the biomechanical properties of repaired tendons. Furthermore, the COX2 inhibitor parecoxib reduces PGE2 but impairs the biomechanical properties of repaired tendons. Interestingly, PGE2 local treatment improves the biomechanical properties of the repaired tendons. These findings clarify the complex role of PGE2 in peritendinous adhesion formation (PAF) and tendon repair.

Patellar tendon restoration techniques: a systematic review of outcomes for repair and reconstruction methods.

PURPOSE: This systematic review aims to delineate the various methods to repair or reconstruct the patellar tendon using the available literature. METHODS: MEDLINE and PubMed electronic databases were searched for English language clinical studies involving patellar tendon rupture repair or reconstruction that reported patient-reported outcome scores (PROS) between January 1st, 1953 and June 17th, 2021. Data was extracted on full text articles to collect functional outcome scores and rupture category, including acute, chronic, post-total knee arthroplasty (TKA) and post-anterior cruciate ligament reconstruction (ACLR). RESULTS: Twenty-three studies with a total of 738 patients were included. Of the 14 studies including acute repairs, mean postoperative Lvsholm scores ranged from 84 to 99.5. Knee Society Score (KSS) and knee range of motion (ROM) measurement were the most widely reported outcomes in the chronic setting. The average postoperative KSS scores ranged from 70 to 87.7. Of the six studies that included patellar tendon repairs/reconstructions in the setting of prior TKA, the most frequently reported outcomes were KSS scores and knee ROM measurements. The average postoperative KSS scores for the three cohorts reporting reconstruction with allograft ranged from 79 to 88 as compared to the average postoperative KSS score for reconstruction with autograft of 70. CONCLUSION: Despite this heterogeneity, we concluded: (1) in the primary setting, cerclage augmentation yields the lowest lysholm scores and should not be considered, although primary repairs with and without augmentation yield comparable postoperative lysholm scores, (2) in the chronic setting, repair with augmentation and reconstruction yielded similar results aside from in post-TKA patients where allograft reconstruction yielded superior KSS scores.

Sensory Neuropraxia After Distal Biceps Repair is Not Associated With Patient-Reported Outcomes or Satisfaction: A Retrospective Cohort Study.

BACKGROUND: Cutaneous neuropraxia is the most common complication following distal biceps tendon repair (DBTR). Currently, no patient demographic factors have been implicated in its occurrence, course, or resolution. The purpose of this study is to explore various patient demographics and their association with postoperative neuropraxia. Further it investigates how mental health scores correlate with patient-reported outcomes, and whether occurrence of neuropraxia alters this association. METHODS: This retrospective review evaluates a consecutive series of patients who underwent distal biceps repair with a single-incision cortical button technique. Patients with reported outcome data at a minimum of 1 year (n = 47) were included for analysis. Demographic data including age, sex, body mass index (BMI), diabetes, smoking status, and occurrence of neuropraxia were recorded. Patient-reported outcome measures (PROMs) include the American Shoulder and Elbow Surgeons-Elbow (ASES-E) score, Single Assessment Numeric Evaluation (SANE) score, Visual Analog Scale (VAS) for pain, Disabilities of the Arm, Shoulder, and Hand Score (QuickDASH), and Veterans RAND 12 (VR-12) Mental Component Score (MCS) and Physical Component Score (PCS) quality-of-life assessment. RESULTS: Postoperative neuropraxia of any duration occurred in 45% (21/47) of patients in this cohort following DBTR. Of these, 62% (13/21) reported resolution of symptoms by the latest follow-up. Mean time to resolution of neuropraxia was 148 days. Patient age, BMI, smoking history, time to surgery, tear thickness, and increasing surgeon experience across the study period were not significantly associated with the incidence or time to resolution of postoperative neuropraxia. Scores for patient satisfaction, VAS, ASES, QuickDASH, SANE, VR-12 MCS, VR-12 PCS, and flexion ROM did not differ significantly between patients with and without postoperative neuropraxia. CONCLUSION: Patient satisfaction following DBTR was not significantly associated with postoperative neuropraxia. Patient and surgical characteristics did not influence the occurrence or time to resolution of neuropraxia. The occurrence of postoperative neuropraxia did not result in significant functional limitations.

The influence of oblique sutures and tendon-suture anchorages on tensile resistance and ultimate strength of 4-strand tendon repairs.

This study investigated whether the integration of the oblique sutures contributes to the resistance to gapping in 4-strand flexor tendon repairs. In 72 porcine tendons, we compared repairs incorporating oblique sutures against those without using three distinct anchorage types. The studied suture configurations were longitudinal and oblique, modified Savage and Adelaide, and modified Kessler and Lahey. The number of tendons that formed the first gap or a 2 mm gap at the repair site during cyclic loading, stiffness at the 1st and 20th cycles, gap size between tendon ends and ultimate strength were recorded. No significant differences were found between core sutures with and without oblique sutures except between the modified Savage and Adelaide sutures. The Kessler-type anchorage was inferior in resisting gap formation than simple grasping or cross-locking sutures. We conclude that an oblique suture does not increase the gap resistance of 4-strand tendon repairs when using grasping or Kessler-type anchorages, but it does when using a cross-locking anchorage, such as the Adelaide suture. Simple grasping anchorage is comparable to cross-locking in resisting gap formation.

Outcomes of Zone II Flexor Tendon Repair Under General Versus Wide Awake Local Anesthesia: A Randomized Controlled Trial.

PURPOSE: Wide awake local anesthesia no tourniquet (WALANT) is gaining popularity with flexor tendon repair. We hypothesized that results of zone II flexor tendon repair performed under WALANT would be superior to those performed under general anesthesia (GA). METHODS: A randomized controlled trial was conducted to compare results of repair of zone II flexor tendon lacerations under WALANT versus GA. Following sample size estimation, 86 digits were included and randomized into two groups. All surgeries were performed by a single surgeon using a six-stranded core stitch and running epitenon suture. All patients followed the same early active rehabilitation protocol. The primary outcome was recovery calculated using the Strickland and Glogovac criteria. Secondary outcomes included rupture rate, complication rate, and Disabilities of the Arm, Shoulder, and Hand (DASH) score. All outcomes were reported at the 6-month visit for all patients. RESULTS: Of the 86 digits, three were lost to follow-up. Analysis was performed on 43 digits in the WALANT group and 40 in the GA group. Demographic characteristics including age and sex were comparable in both groups. Rupture of the repair occurred in two digits in each of the WALANT and GA groups. An excellent or good outcome was achieved in 49% and 56% of the digits in the WALANT and GA groups, respectively. This difference was not statistically significant. DASH scores averaged 12.9 and 8.4 for the WALANT and GA groups, respectively. CONCLUSIONS: WALANT may not be superior to GA in regards function, rates of rupture, and patient-reported outcomes in repair of zone II flexor tendon lacerations. Surgeons can be confident in choosing either technique if rigorous patient selection, sound surgical technique, and proper hand therapy are employed. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

Biomechanical Analysis of a New Odd-Numbered Strand Suture Technique for Early Active Mobilization After Primary Flexor Tendon Repair.

Purpose: The placement of multistrand sutures during flexor tendon repair is complex and challenging. We developed a new, simpler, nine-strand suture, which we term the Tajima nines. The Tajima nines repair method is a new odd-numbered strand tendon technique. Methods: Fourteen porcine flexor tendons were transected and repaired using the Tajima nines repair method, without placement of peripheral sutures. This technique is a modification of the Lim and Tsai repair method; it uses a 4-0 monofilament nylon, 3-strand line, and two needles. The repaired tendons were tested for linear, noncyclic, load-to-failure tensile strength. The initial gap, 2-mm gap-formation force, and ultimate strength were measured. Results: The initial gap-formation force was 27.9 ± 7.5 newtons (N), the 2-mm gap-formation force was 39.2 ± 4.7 N, and the ultimate strength was 76.7 ± 17.2 N. Eight, three, and three of the 14 tendons repaired using the Tajima nines method demonstrated failure because of thread breakage, knot failure, and suture pull-out, respectively. Conclusions: This biomechanical study demonstrated that Tajima nines repair was associated with particularly high initial tension at the repair site; there were minor variations in the initial load and 2-mm gap-formation load. Our results suggest that Tajima nines repair with peripheral suturing allows the repaired flexor tendon to tolerate the stresses encountered during early active mobilization. Clinical relevance: This simple nine-strand technique will be particularly useful for inexperienced surgeons who perform early active mobilization after primary flexor tendon repair because the technique is a modification of the Lim and Tsai repair method using a triple strand instead of a double strand.

Galangin Promotes Tendon Repair Mediated by Tendon-Derived Stem Cells through Activating the TGF-ß1/Smad3 Signaling Pathway.

Tendon injury is a prevalent orthopedic disease that currently lacks effective treatment. Galangin (GLN) is a vital flavonoid found abundantly in galangal and is known for its natural activity. This study aimed to investigate the GLN-mediated molecular mechanism of tendon-derived stem cells (TDSCs) in tendon repair. The TDSCs were characterized using alkaline phosphatase staining, alizarin red S staining, oil red O staining, and flow cytometry. The effect of GLN treatment on collagen deposition was evaluated using Sirius red staining and quantitative (q)PCR, while a Western bot was used to assess protein levels and analyze pathways. Results showed that GLN treatment not only increased the collagen deposition but also elevated the mRNA expression and protein levels of multiple tendon markers like collagen type I alpha 1 (COL1A1), decorin (DCN) and tenomodulin (TNMD) in TDSCs. Moreover, GLN was also found to upregulate the protein levels of transforming growth factor ß1 (TGF-ß1) and p-Smad3 to activate the TGF-ß1/Smad3 signaling pathway, while GLN mediated collagen deposition in TDSCs was reversed by LY3200882, a TGF-ß receptor inhibitor. The study concluded that GLN-mediated TDSCs enhanced tendon repair by activating the TGF-ß1/Smad3 signaling pathway, suggesting a novel therapeutic option in treating tendon repair.

The roles and mechanisms of the NF-κB signaling pathway in tendon disorders.

Both acute and chronic tendon injuries are the most frequently occurring musculoskeletal diseases in human and veterinary medicine, with a limited repertoire of successful and evidenced-based therapeutic strategies. Inflammation has been suggested as a key driver for the formation of scar and adhesion tissue following tendon acute injury, as well as pathological alternations of degenerative tendinopathy. However, prior efforts to completely block this inflammatory process have yet to be largely successful. Recent investigations have indicated that a more precise targeted approach for modulating inflammation is critical to improve outcomes. The nuclear factor-kappaB (NF-κB) is a typical proinflammatory signal transduction pathway identified as a key factor leading to tendon disorders. Therefore, a comprehensive understanding of the mechanism or regulation of NF-κB in tendon disorders will aid in developing targeted therapeutic strategies for human and veterinary tendon disorders. In this review, we discuss what is currently known about molecular components and structures of basal NF-κB proteins and two activation pathways: the canonical activation pathway and the non-canonical activation pathway. Furthermore, we summarize the underlying mechanisms of the NF-κB signaling pathway in fibrosis and adhesion after acute tendon injury, as well as pathological changes of degenerative tendinopathy in all species and highlight the effect of targeting this signaling pathway in tendon disorders. However, to gain a comprehensive understanding of its mechanisms underlying tendon disorders, further investigations are required. In the future, extensive scientific examinations are warranted to full characterize the NF-κB, the exact mechanisms of action, and translate findings into clinical human and veterinary practice.

Therapeutic potential of GDF-5 for enhancing tendon regenerative healing.

Tendon injury is a common disorder of the musculoskeletal system, with a higher possibility of occurrence in elderly individuals and athletes. After a tendon injury, the tendon suffers from inadequate and slow healing, resulting in the formation of fibrotic scar tissue, ending up with inferior functional properties. Therapeutic strategies involving the application of growth factors have been advocated to promote tendon healing. Growth and differentiation-5 (GDF-5) represents one such factor that has shown promising effect on tendon healing in animal models and in vitro cultures. Although promising, these studies are limited as the molecular mechanisms by which GDF-5 exerts its effect remain incompletely understood. Starting from broadly introducing essential elements of current understanding about GDF-5, the present review aims to define the effect of GDF-5 and its possible mechanisms of action in tendon healing. Nevertheless, we still need more in vivo studies to explore dosage, application time and delivery strategy of GDF-5, so as to pave the way for future clinical translation.

Pectoralis major tendon rupture repairs using intramedullary suture anchors shows high patient-reported outcomes in military service members.

BACKGROUND: In the general population, pectoralis major tendon ruptures are uncommon; however, it is a common injury in the military population. The military service members have greater physical demands than the general population. The purpose of this study is to critically assess the postoperative outcomes of pectoralis major tendon ruptures in military service members following a repair using intramedullary suture anchors. METHODS: A retrospective chart review was performed between 2014 and 2022, identifying patients who underwent a pectoralis major rupture repair performed by the senior surgeon using intramedullary suture anchors. Records were reviewed for age, gender, mechanism of injury, chronicity, visual analog scale, and Single Assessment Numeric Evaluation (SANE) scores. Patients who had less than 1 year of follow-up were excluded from the study. During the study period, 18 patients underwent surgical repair of their torn pectoralis major, and 15 patients were followed up >1 year postoperatively. Twelve of these 15 patients (80%) were successfully contacted, and patient-reported outcomes were collected. RESULTS: A total of 12 patients (12 male, 0 female) with a mean age of 34.5 years were identified. Average time from injury to surgery was 471.4 days. Average duration of follow-up was 3.7 years. There was a decrease in the preoperative average single repetition maximum (1RM) barbell bench press of 125.7 kg (277 lbs) to a postoperative average 1RM bench press of 101.8 kg (225 lbs) (P = .03). Mean change in average 1RM barbell bench press is a 19.04% decrease postoperatively. Postoperative SANE score was 80.8 and an American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score of 86.9. Seven patients (58.3%) stated they were afraid to bench press at their previous weight because of fear of reinjury. None of the patients were medically discharged from the military owing to limitations from their repaired shoulder. Ten patients (83%) reported they were extremely satisfied with their shoulder function postoperatively. CONCLUSION: Repair of the pectoralis major tendon ruptures using intramedullary suture anchors has high rates of return to duty, patient satisfaction, and patient-reported outcomes. More than half of the patients reported they were afraid to bench press at their preinjury weight because of concerns of reinjury; the decrease in postoperative strength may be a result of the patients' fear of reinjury rather than physiologic limitations.

Tendon extracellular-matrix-derived tissue engineering micro-tissue for Achilles tendon injury regeneration in rats.

BACKGROUND: Achilles tendon is vital in maintaining the stability and function of ankle joint. It is quite difficult to achieve the structural and functional repair of Achilles tendon in tissue engineering. METHODS: A tissue-engineered tendon micro-tissue was prepared using rat tail tendon extracellular matrix (TECM) combined with rat adipose stem cells (ADSCs) to repair Achilles tendon injuries. The TECM was prepared by repeated freezing and thawing. The in vitro characteristics of TECM and its effect on ADSCs proliferation were detected. This tissue-engineered tendon micro-tissue for Achilles tendon repair in vivo was evaluated based on general characteristics, gait analysis, ultrasound findings, histological analysis, and biomechanical testing. RESULTS: The results showed that the TECM scaffold had good biocompatibility for ADSCs. At 2 weeks post-surgery, collagen types I and III and tenomodulin expression were higher, and vascular endothelial growth factor expression was lower in the micro-tissue group than other groups. At 4 and 8 weeks post-surgery, the results of histological analysis and ultrasound findings showed that the repaired tendon tissue was smooth and lustrous, and was arranged regularly and evenly in the micro-tissue group. Gait analysis confirmed that better motor function recovery was noted in micro-tissue group than other groups. In addition, the mechanical properties of the repaired tendon tissue in micro-tissue group were better than other groups. CONCLUSION: Tissue-engineered tendon micro-tissue fabricated by TECM and ADSCs has good biocompatibility and can promote structural and functional repair of tendon in vivo. This composite biomaterial has broad application prospects in tissue engineering.

Hyaluronic acid/PEO electrospun tube reduces tendon adhesion to levels comparable to native tendons - An in vitro and in vivo study.

A major problem after tendon injury is adhesion formation to the surrounding tissue leading to a limited range of motion. A viable strategy to reduce adhesion extent is the use of physical barriers that limit the contact between the tendon and the adjacent tissue. The purpose of this study was to fabricate an electrospun bilayered tube of hyaluronic acid/polyethylene oxide (HA/PEO) and biodegradable DegraPol® (DP) to improve the anti-adhesive effect of the implant in a rabbit Achilles tendon full laceration model compared to a pure DP tube. Additionally, the attachment of rabbit tenocytes on pure DP and HA/PEO containing scaffolds was tested and Scanning Electron Microscopy, Fourier-transform Infrared Spectroscopy, Differential Scanning Calorimetry, Water Contact Angle measurements, and testing of mechanical properties were used to characterize the scaffolds. In vivo assessment after three weeks showed that the implant containing a second HA/PEO layer significantly reduced adhesion extent reaching levels comparable to native tendons, compared with a pure DP implant that reduced adhesion formation only by 20 %. Tenocytes were able to attach to and migrate into every scaffold, but cell number was reduced over two weeks. Implants containing HA/PEO showed better mechanical properties than pure DP tubes and with the ability to entirely reduce adhesion extent makes this implant a promising candidate for clinical application in tendon repair.

Mental and behavioural disorders increase the risk of tendon rupture after flexor tendon repair in zone I and II.

Introduction: The effect of mental and behavioural disorders (MBD) on the risk of tendon ruptures after flexor tendon repair is not well understood. This study aimed to analyse the association between MBD and tendon rupture after flexor tendon repair in zones I and II. Methods: Data from the Swedish National Registry for Hand Surgery (HAKIR) on patients with a complete flexor tendon repair at our department between 2012 and 2019 were followed for a minimum of 2 years to assess the rate of rupture. Independent variables were collected from HAKIR and clinical records: prevalence MBD based on ICD-10 codes F0-F99, age, sex, injured tendon, number of injured fingers, day to surgery, core suture, digital nerve injury, smoking, injury mechanism, and rehabilitation method. Multiple logistic regression was used to assess the association between variables. Results: A cohort of 593 patients with 49 ruptures (8.2%) was identified. Potential causes of rupture were non-adherence behaviour in 16 (33%), accidents in seven (14%), infections in six (12%), and no clear cause in 20 (41%) patients. Patients with MBD had an association to rupture (OR 3.6), 17.7% ruptures compared to 7.2% in patients with no diagnosed disorders. Patients >50 years of age had a higher risk compared to patients <25 years (OR 4.3), 15% compared to 3.9%' respectively. Men had a higher risk compared to women (OR 2.9), 10% compared to 4.3%' respectively. Conclusion: We identified an association between the prevalence of mental and behavioural disorders and rupture after flexor tendon repair.

Biomechanical strength of triceps tendon repairs: systematic review and meta-regression analysis of human cadaveric studies.

PURPOSE: It is unclear which triceps tendon repair constructs and techniques produce the strongest biomechanical performance while minimizing the risk of gap formation and repair failure. We aimed to determine associations of construct and technique variables with the biomechanical strength of triceps tendon repairs. PubMed, Embase, Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov were systematically searched for peer-reviewed studies on biomechanical strength of triceps tendon repairs in human cadavers. 6 articles met the search criteria. Meta-regression was performed on the pooled dataset (123 specimens). Outcomes of interest included gap formation, failure mode, and ultimate failure load. Covariates were fixation type; number of implants; and number of sutures. Stratification by covariates was performed. We found no association between fixation type and ultimate failure load; however, suture anchor fixation was associated with less gap formation compared with transosseous direct repair (ß = - 1.1; 95% confidence interval [CI]:- 2.2, - 0.04). A greater number of implants was associated with smaller gap formation (ß = - 0.77; 95% CI: - 1.3, - 0.28) while a greater number of sutures was associated with higher ultimate failure load ( ß= 3; 95% CI: 21, 125). In human cadaveric models, the number of sutures used in triceps tendon repairs may be more important than the fixation type or number of implants for overall strength. If using a transosseous direct repair approach to repair triceps tendon tears, surgeons may choose to use more sutures in their repair in order to balance the risk of larger gap formation when compared to indirect repair techniques. LEVEL OF EVIDENCE: Level III.

The current status of various preclinical therapeutic approaches for tendon repair.

Tendons are fibroblastic structures that link muscle and bone. There are two kinds of tendon injuries, including acute and chronic. Each form of injury or deterioration can result in significant pain and loss of tendon function. The recovery of tendon damage is a complex and time-consuming recovery process. Depending on the anatomical location of the tendon tissue, the clinical outcomes are not the same. The healing of the wound process is divided into three stages that overlap: inflammation, proliferation, and tissue remodeling. Furthermore, the curing tendon has a high re-tear rate. Faced with the challenges, tendon injury management is still a clinical issue that must be resolved as soon as possible. Several newer directions and breakthroughs in tendon recovery have emerged in recent years. This article describes tendon injury and summarizes recent advances in tendon recovery, along with stem cell therapy, gene therapy, Platelet-rich plasma remedy, growth factors, drug treatment, and tissue engineering. Despite the recent fast-growing research in tendon recovery treatment, still, none of them translated to the clinical setting. This review provides a detailed overview of tendon injuries and potential preclinical approaches for treating tendon injuries.

Factors predicting the adhesion and prolonged lost days of work in patients with extensor tendon adhesion of the hand.

Objective: Extensor tendon adhesion receive less attention recently. This study aims to analyze influencing factors of adhesion and prolonged lost days of work in patients with extensor tendon adhesion of the hand. Method: We performed a retrospective study in patients with extensor tendon injuries who underwent primary surgical repair and early rehabilitation. We observed the differences between non-tendon adhesion and adhesion patients after surgical repair, and used the receiver operating characteristic curve to distinguish them. Then we explored the influencing factors of adhesion. In addition, we studied the lost days of work and the influencing factors. Results: A total of 305 patients were included. 24.6% patients appeared tendon adhesion and the mean lost days of work was 12 weeks. MHISS scores, VAS scores, occupation and blood triglyceride level were the influencing factors of adhesion. The adhesion patients have increased MHISS scores (p < 0.001), VAS scores (p < 0.001), blood triglyceride levels (p < 0.001) and lost days of work (p < 0.001) than non-tendon adhesion. The optimal cut-off value of blood triglyceride level to distinguish non-tendon adhesion from adhesion was 1.625 mml/L, and MHISS scores was 20.5. Smoking, MHISS scores, blood triglyceride levels were the influencing factors of lost days of work in adhesion patients. There was positive correlation between lost days of work and triglyceride level (r = 0.307, p = 0.007), and MHISS scores (r = 0.276, p = 0.016). Conclusion: To minimize the occurrence of adhesion, doctors should pay attention to patients with higher MHISS and VAS scores, blood triglyceride levels, especial for the blue-collar and unemployed one. High triglyceride level may be a new influencing factor.

Short-Term and Long-Term Therapeutic Results of Deep Flexor Tendon Repair in Zone II in Patients Referred to Imam Khomeini Hospital, Ahvaz, Southern Iran.

Background: Hand injury as an important concern for the surgeon and the patient requires proper and timely treatment to prevent complications such as infection and adhesions, and with a proper rehabilitation program, the patient returns to maximum function as soon as possible. We aimed to investigate the short-term and long-term treatment results of deep flexor tendon repair in in zone II. Methods: This retrospective study was performed on 34 patients with 45 injured fingers in the zone II referred to Ahvaz Imam Khomeini Hospital, Ahvaz, Iran during 2017-2019. The results of deep flexor tendons repair in two groups, immediate and delayed primary repair were assessed. Results: The mean age of the patients was 27.76 years. There was no significant remarkable between male and female in the incidence of complications such as infection, tendon rupture and adhesions. 29.4% (n=10) had poor outcome, 8.8% (n=3) had fair outcome, 29.4% (n=10) had good outcome and 32.4% (n=11) had excellent outcomes. 26.5% had adhesion and infection rate was 11.8%. Conclusion: Among surgeons, there is consensus for the primary repair of tendon injury, but there was no significant difference between the results of immediate and delayed primary repair. Although physiotherapy has been suggested as an effective factor in improving hand function, its positive effect on the range of motion of the fingers has not been proven.

A Simple Technique Ensuring Adequate Exposure During Primary Repair of Complex Thumb Injuries.

As the thumb is pronated, primary repair of complex injuries may be more difficult than the repair of other digits. We describe a simple technique that facilitates thumb repair. We insert a Kirschner wire perpendicular to the bone axis in the middle of the proximal phalanx, which ensures adequate exposure of the palmar aspect without the need for thumb position adjustment by an assistant. This technique is particularly useful when inexperienced surgeons perform thumb replantation and primary flexor tendon repair using a multistrand suture technique.

Injectable self-assembled GDF5-containing dipeptide hydrogels for enhanced tendon repair.

Owing to the tissue characteristics of tendons with few blood vessels and cells, the regeneration and repair of injured tendons can present a considerable challenge, which considerably affects the motor function of limbs and leads to serious physical and mental pain, along with an economic burden on patients. Herein, we designed and fabricated a dipeptide hydrogel (DPH) using polypeptides P11-4 and P11-8. This hydrogel exhibited self-assembly characteristics and could be administered in vitro. To endow the hydrogel with differentiation and regeneration abilities, we added different concentrations of growth differentiation factor 5 (GDF5) to form GDF5@DPH. GDF5@DPH promoted the aggregation and differentiation of tendon stem/progenitor cells and promoted the regeneration and repair of tendon cells and collagen fibers in injured areas. In addition, GDF5@DPH inhibited inflammatory reactions in the injured area. Owing to its injectable properties, DPH can jointly inhibit adhesion and scar hyperplasia between tissues caused by endogenous inflammation and exogenous surgery and can provide a favorable internal environment for the regeneration and repair of the injured area. Overall, the GDF5@DPH system exhibits considerable promise as a novel approach to treating tendon injury.

Janus Membranes Patch Achieves High-Quality Tendon Repair: Inhibiting Exogenous Healing and Promoting Endogenous Healing.

The imbalance between endogenous and exogenous healing is the fundamental reason for the poor tendon healing. In this study, a Janus patch was developed to promote endogenous healing and inhibit exogenous healing, leading to improved tendon repair. The upper layer of the patch is a poly(dl-lactide-co-glycolide)/polycaprolactone (PLGA/PCL) nanomembrane (PMCP-NM) modified with poly(2-methylacryloxyethyl phosphocholine) (PMPC), which created a lubricated and antifouling surface, preventing cell invasion and mechanical activation. The lower layer is a PLGA/PCL fiber membrane loaded with fibrin (Fb) (Fb-NM), serving as a temporary chemotactic scaffold to regulate the regenerative microenvironment. In vitro, the Janus patch effectively reduced 92.41% cell adhesion and 79.89% motion friction. In vivo, the patch inhibited tendon adhesion through the TGF-ß/Smad signaling pathway and promoted tendon maturation. This Janus patch is expected to provide a practical basis and theoretical guidance for high-quality soft tissue repair.