Principles for Achieving Predictable Outcomes in Flexor Tendon Repair

Flexor tendon injuries require surgical repair. Early repair is optimal, but staged repair may be indicated for delayed presentations. Zone II flexor tendon injuries are the most difficult to achieve acceptable outcomes and require special attention for appropriate repair. Surgical techniques to repair flexor tendons have evolved over the past several decades and principles include core strand repair using at least a 4 strand technique, epitendinous suture to add strength and gliding properties, and pulley venting. Early postoperative active range of motion within the first 3 to 5 days of surgery is essential for optimizing outcomes.

Zone-specific pitfalls in flexor tendon rehabilitation: management and prevention

Despite significant advancements in flexor tendon repair techniques and rehabilitation strategies, achieving complete restoration of digital motion remains a formidable challenge. The most prevalent complications associated with tendon repair are the development of tendon adhesions and joint contractures. Left unaddressed, these complications can further lead to secondary pathomechanical changes, resulting in fixed deformities significantly affecting hand function. This review of zone-specific considerations in flexor tendon rehabilitation provides an in-depth analysis of the dynamics of tendon motion after repair and strategies to minimize common secondary complications.

Construct validation of a novel synthetic tendon model used for assessing surgeon performance in a simulated core suture tendon repair technique

BACKGROUND

The strength of tendon repair is dependent on the quality of the core suture. Organic and synthetic materials have been used to simulate tendon repair for training; however, no model has undergone construct validation.

OBJECTIVES

To determine the construct validity of a novel synthetic tendon repair model.

METHODS

Synthetic silicone tendon models were used to simulate adult Achilles tendon (AT) and digital flexor tendon (FT). Participants were categorised into novice, intermediate, and advanced groups based on prior surgical experience. Participants repaired tendons using the modified Kessler technique. A validated motion analysis system was used to measure the duration, path length, and movement count during the simulated task. A global rating score was also used to assess the performance.

RESULTS

All participants in the novice (n = 12), intermediate (n = 8) and advanced (n = 11) groups completed the tasks. The results (mean±standard deviation) were duration (872 ± 335, 492 ± 257 and 357 ± 40 s), path length (9493 ± 3173, 6668 ± 1740 and 4672 ± 1228 cm), movement count (4974 ± 673, 4228 ± 259 and 3962 ± 69) and global rating (39 ± 13, 61 ± 14, 81 ± 5), respectively. The Kruskal-Wallis test was significant for all outcome measures (p < 0.01). Significant differences in duration and movement count were identified post-hoc in the AT model for each experience group (p < 0.05), and between novice and intermediate participants for FT repair (p < 0.04). Global rating was significantly different between all groups and was highly correlated with motion metrics (p < 0.01).

CONCLUSION

The results support construct validity of this novel simulated tendon repair model. The global rating scores may allow wide utility of this simulation. This model provides a valid and safe environment for surgical trainees to practice tendon repair with several cost, ethical and logistical benefits over animal tendon use. 248/250.

Current clinical opinion on surgical approaches and rehabilitation of hand flexor tendon injury-a questionnaire study

The management of flexor tendon injury has seen many iterations over the years, but more substantial innovations in practice have been sadly lacking. The aim of this study was to investigate the current practice of flexor tendon injury management, and variation in practice from the previous reports, most troublesome complications, and whether there was a clinical interest in potential innovative tendon repair technologies. An online survey was distributed via the British Society for Surgery of the Hand (BSSH) and a total of 132 responses were collected anonymously. Results showed that although most surgeons followed the current medical recommendation based on the literature, a significant number of surgeons still employed more conventional treatments in clinic, such as general anesthesia, ineffective tendon retrieval techniques, and passive rehabilitation. Complications including adhesion formation and re-rupture remained persistent. The interest in new approaches such as use of minimally invasive instruments, biodegradable materials and additive manufactured devices was not strong, however the surgeons were potentially open to more effective and economic solutions.

Biomechanical Evaluation of a Tubular Braided Construct for Primary Deep Flexor Tendon Surgery

PURPOSE

Immediate postoperative mobilization has been shown to avoid adhesion formation and improve range of motion after flexor tendon repair. A tubular braided construct was designed to allow for these rehabilitation protocols.

METHODS

In this ex vivo study, 92 ovine flexor tendons were divided randomly into 2 equal groups. After creating a transection, the tendons of the first group were repaired using a tubular braided construct. This construct, consisting of a tubular braid of polypropylene and polyethylene terephthalate fibers, exerts a grasping effect on the tendon ends. The control group received a multistrand modified Kessler repair with a looped polydioxanone suture (PDS) 4-0 suture and a Silfverskiöld epitendinous repair using an Ethilon 6-0 suture. After the repair, a static and an incremental cyclic tensile test was performed until failure.

RESULTS

During the static test, the tubular braid resulted in a significantly higher load at 3 mm gap formation (86.3 N ± 6.0 vs 50.1 N ± 11.6), a higher ultimate load at failure (98.3 N ± 12.7 vs 63 N ± 11.1), higher stress at ultimate load (11.8 MPa ± 1.2 vs 8.1 MPa ± 3.1), and higher stiffness (7.1 N/mm ± 2.9 vs 8.7 N/mm ± 2.2). For the cyclic tests, survival analyses for 1-, 2- and 3-mm gap formation and failure demonstrated significant differences in favor of the tubular braided construct.

CONCLUSION

The tubular braided construct withstands the required loads for immediate rehabilitation not only in static tests, but also during cyclic tests. This is in contrast with the control group, where sufficient strength is reached during static tests, but failures occur below the required loads during cyclic testing.

CLINICAL RELEVANCE

The tubular braided construct provides a larger safety margin for immediate intensive rehabilitation protocols.

Comparison of surgical trends in zone 2 flexor tendon repair between Turkish and international surgeons

Objectives

The aim of this study was to evaluate Turkish trends in zone 2 flexor repair with regards to surgical technique, suture materials, anesthesia and post-operative rehabilitation and compare this with international surgeons by modifying Gibson's survey.

Methods

A printed and online survey consisting of 19 questions modified from Gibson's survey was sent to 590 Turkish and international surgeons. The surgeon's years in practice, province of practice, residency type, number of zone 2 flexor tendon repairs done in a year, preferred surgical technique, suture material, complications and postoperative protocols were asked to the respondents.

Results

A total of 194 surgeons completed the survey (a 25% response rate). Of those who completed the survey, 91 were international (mostly from far eastern countries) and 103 were Turkish surgeons. Years in practice and educational background had influence on the decision-making. There were differences between the Turkish and international surgeons in the core and epitendinous suture thickness preference and flexor tendon sheath repair. There was a statistically significant relationship between the province of practice and the use of WALANT (Wide awake local anesthesia no tourniquet) (p < 0.05). While the majority of respondents who preferred postoperative early passive motion protocol were from Turkey (61.5%), the majority of respondents who preferred early active motion protocol were practicing abroad (73.9%).

Conclusion

Despite some variations the surgeons involved in this study follow to a large extent the current literature.

A Biomechanical Study of a Novel Asymmetric 6-Strand Flexor Tendon Repair Using Porcine Tendons

BACKGROUND

This study evaluated the biomechanical performance of a novel asymmetric 6-strand flexor tendon repair technique without locking loops.

METHODS

Twenty porcine flexor tendons were equally repaired by using the asymmetric technique and compared with the modified Lim-Tsai repair technique. The ultimate tensile strength, load to 1-mm gap force, stiffness, and mechanism of failure were measured.

RESULTS

The asymmetric repair technique had significantly higher tensile strength (63.3 ± 3.7 N) than the modified Lim-Tsai repairs (46.7 ± 8.3 N).

CONCLUSIONS

A novel flexor tendon repair technique with improved biomechanical performance may be available for use in flexor tendon repairs.

Zone II Flexor Tendon Repairs in the United States: Trends in Current Management

PURPOSE

The repair of zone II flexor tendon injuries is an evolving topic in hand surgery with current literature suggesting the use of a 4-strand repair; 3-0 or 4-0 braided, nonabsorbable sutures; and an epitendinous repair. It was hypothesized that variability would exist within the hand surgeon community in treatment of zone II flexor tendon repairs in surgical material used, surgical technique, and postoperative rehabilitation protocol.

METHODS

An online single-answer multiple-choice survey was distributed to the American Society for Surgery of the Hand members' database. Surgeons were asked questions about demographics, surgical technique, suture type, common complications, postoperative management, and the factor that plays the largest role in guiding their surgical preferences. Responses were compared with current medical evidence.

RESULTS

A total of 410 individuals responded to the survey. In regards to technique, the majority of surgeons reported using a 4-strand repair; with 3-0 or 4-0 core braided, nonabsorbable sutures; and performing an epitendinous repair. Only 20% of surgeons surveyed reported ever using wide-awake local anesthesia, no tourniquet and postoperative protocols were split between early active and early passive rehabilitation. Senior surgeons (≥ 15 years in practice) were more likely than their colleagues to use a 2-strand repair and a passive rehabilitation protocol.

CONCLUSIONS

This study demonstrates that the majority of respondents are performing zone II flexor tendon repairs in accordance with the best currently available evidence, although there is variability with respect to suture material, surgical technique, and rehabilitation protocols.

CLINICAL RELEVANCE

There is still a need for high-quality studies on surgical technique and rehabilitation protocols.

A Clinical, Biological, and Biomaterials Perspective into Tendon Injuries and Regeneration

Tendon injury is common and debilitating, and it is associated with long-term pain and ineffective healing. It is estimated to afflict 25% of the adult population and is often a career-ending disease in athletes and racehorses. Tendon injury is associated with high morbidity, pain, and long-term suffering for the patient. Due to the low cellularity and vascularity of tendon tissue, once damage has occurred, the repair process is slow and inefficient, resulting in mechanically, structurally, and functionally inferior tissue. Current treatment options focus on pain management, often being palliative and temporary and ending in reduced function. Most treatments available do not address the underlying cause of the disease and, as such, are often ineffective with variable results. The need for an advanced therapeutic that addresses the underlying pathology is evident. Tissue engineering and regenerative medicine is an emerging field that is aimed at stimulating the body's own repair system to produce de novo tissue through the use of factors such as cells, proteins, and genes that are delivered by a biomaterial scaffold. Successful tissue engineering strategies for tendon regeneration should be built on a foundation of understanding of the molecular and cellular composition of healthy compared with damaged tendon, and the inherent differences seen in the tissue after disease. This article presents a comprehensive clinical, biological, and biomaterials insight into tendon tissue engineering and regeneration toward more advanced therapeutics.

The past, present and future in scaffold-based tendon treatments

Tendon injuries represent a significant clinical burden on healthcare systems worldwide. As the human population ages and the life expectancy increases, tendon injuries will become more prevalent, especially among young individuals with long life ahead of them. Advancements in engineering, chemistry and biology have made available an array of three-dimensional scaffold-based intervention strategies, natural or synthetic in origin. Further, functionalisation strategies, based on biophysical, biochemical and biological cues, offer control over cellular functions; localisation and sustained release of therapeutics/biologics; and the ability to positively interact with the host to promote repair and regeneration. Herein, we critically discuss current therapies and emerging technologies that aim to transform tendon treatments in the years to come.