Epitendinous suture techniques in extensor tendon repairs--an experimental evaluation

Flexor tendon injuries: Repair & Rehabilitation

Flexor tendon injuries are common and occur mostly by penetrating trauma. Suspected flexor tendon injuries require a thorough clinical assessment and often are not isolated injuries. A detailed understanding of flexor tendon anatomy and spatial relationships is essential, especially when repairing multi-tendon injuries. Principles of flexor tendon repair include a strong suture construct, minimising gap formation between tendon ends, preserving tendon blood supply and providing a smooth repair interface. Moreover, adequate exposure of the zone of injury using full-thickness skin flaps and preservation of neurovascular and pulley structures is essential. In this article an overview of contemporary management strategies is presented. Today's hand surgeons and therapists can choose from a variety of treatment options when managing these important and potentially life-changing injuries.

Biomechanical comparison of three epitendinous suture patterns as adjuncts to a core locking loop suture for repair of canine flexor tendon injuries

OBJECTIVE

To determine the effects of different epitendinous sutures (ES) in addition to core locking-loop (LL) sutures on the mechanical properties and gap formation in a canine cadaveric tendon model.

STUDY DESIGN

Experimental, ex vivo, biomechanical study.

SAMPLE POPULATION

Seventy-two cadaveric superficial digital flexor tendon specimens.

METHODS

Superficial digital flexor tendon specimens were divided into four groups (n = 18): sharply transected and repaired with LL, LL + simple continuous ES, LL + Silfverskiöld cross-stitch ES, and LL + interlocking horizontal mattress ES. Constructs were loaded to monotonic failure. Failure modes, gapping, yield, peak, and failure forces were analyzed. Significance was set at P < .05.

RESULTS

Yield, peak, and failure forces increased by 2.5-fold, two-fold, and twofold, respectively when ES groups were compared with core LL suture patterns alone (P < .0001). Resistance to 1- and 3-mm gap formation was greater in ES groups compared with core LL constructs alone (P < .0001). No differences in yield, peak, failure force, or gapping were observed among ES patterns (P > .827).

CONCLUSION

Adding an ES reduced gap formation and increased yield, peak, and failure forces of tenorrhaphies. No difference was detected between the epitendinous patterns tested in this study.

CLINICAL SIGNIFICANCE

The addition of an ES seems more relevant than the specific type of pattern to improve the biomechanical properties of flexor tendon repairs. In vivo studies are warranted to determine the biological implications of the patterns tested here.

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.

Biomechanical investigation of 'figure of 8' flexor tendon repair techniques

This biomechanical study compared the original Al-Qattan repair with other modifications postulated to reduce bulk and friction, thereby potentially improving outcome. A total of 32 cadaveric digits with intact flexor apparatus were used. In each digit, the flexor digitorum profundus and flexor digitorum superficialis tendons were cut cleanly in Zone 2. We tested Al-Qattan's technique along with three modifications using stronger suture material and varying the number of strands across the repair site. Of the four repair techniques, the modified Al-Qattan's technique using two 'figure of 8' 4-0 Fiberwire core sutures (Group 4) had the best balance of ultimate tensile strength (50.9 N), 2 mm gapping force (38 N) and friction. The modified technique provided a stronger repair for early active mobilization and has less friction than the originally described repair.

Effects of different sutures on fibrosis and wound healing in a rabbit model of corneal wounds

The aim of the study was to investigate wound healing and scar formation in rabbit corneal lamellar wounds repaired with simple interrupted sutures (SIS) or horizontal mattress sutures (HMS). Two parallel ‘I’-shaped lamellar cornea wounds were created in one eye of 40 white New Zealand rabbits, while 5 uninjured rabbits were sacrificed to serve as normal controls. One side of the wounds, in the test rabbits, was closed with SIS, while the other side was treated with HMS. Ten days later, the stitches were removed under anesthesia. The animals were sacrificed on days 14 and 21, and months 3 and 6 after the suturing surgery, and corneal samples were subjected to histological and immunofluorescent studies: α-smooth muscle actin (α-SMA) and vimentin were used to detect myofibroblasts and fibroblasts, respectively, and collagen type I and III was used to detect extracellular matrix (ECM) deposition. Relevant mRNA levels were assessed by quantitative polymerase chain reaction (qPCR) to elucidate the differences in wound healing and formation of fibrosis. Macroscopic and hematoxylin and eosin staining observations showed that the two sides of the wounds developed the most prominent fibrotic tissue on day 21. The immunofluorescence and qPCR results showed that HMS wounds produced increased α-SMA, vimentin and collagen type III compared to the SIS wounds on day 14 or 21. The collagen type I expression showed no distinctive difference in SIS and HMS wounds. In conclusion, corneal lamellar wounds treated with SIS developed less fibrotic-related proteins and related mRNA in the early stages of wound healing than wounds treated with HMS. Although differences were not distinct after 3 months, the results of the present study suggest a benefit in choosing SIS over HMS, as at least the initial fibrotic process seems more benign with SIS. Corneal wounds should be carefully sutured, ensuring the tissue is well aligned.

Open extensor tendon injuries

The extensor tendons in the dorsum of the hand lie relatively superficially, making open injuries to the extensor mechanism a common source of morbidity. These injuries can range from simple clean lacerations to complex open injuries associated with severe skin and soft tissue loss. Although many advances in the treatment of tendon injuries focused on the flexor tendon, the extensor tendon has begun to receive more attention in recent literature. Knowledge of modern repair techniques and rehabilitation protocols may improve patient outcomes. This Current Concepts article summarizes the treatment of open extensor tendon injuries with a focus on the recent literature.

The role of animal models in tendon research

Tendinopathy is a debilitating musculoskeletal condition which can cause significant pain and lead to complete rupture of the tendon, which often requires surgical repair. Due in part to the large spectrum of tendon pathologies, these disorders continue to be a clinical challenge. Animal models are often used in this field of research as they offer an attractive framework to examine the cascade of processes that occur throughout both tendon pathology and repair. This review discusses the structural, mechanical, and biological changes that occur throughout tendon pathology in animal models, as well as strategies for the improvement of tendon healing.

Cite this article: Bone Joint Res 2014;3:193–202.

Outcomes of digital zone IV and V and thumb zone TI to TIV extensor tendon repairs using a running interlocking horizontal mattress technique

PURPOSE

Biomechanical evidence has demonstrated that the running interlocking horizontal mattress (RIHM) repair for extensor tendon lacerations is significantly stronger, with higher ultimate load to failure and less tendon shortening compared with other techniques. We investigated the efficacy and safety of primary extensor tendon repair using the RIHM repair technique in the fingers followed by the immediate controlled active motion protocol, and in the thumb followed by a dynamic extension protocol.

METHODS

We conducted a retrospective review of all patients undergoing extensor tendon repair from August 2009 to April 2012 by single surgeon in an academic hand surgery practice. The inclusion criteria were simple extensor tendon lacerations in digital zones IV and V and thumb zones TI to TIV and primary repair performed using the RIHM technique. We included 8 consecutive patients with 9 tendon lacerations (3 in the thumb). One patient underwent a concomitant dorsal hand rotation flap for soft tissue coverage. We used a 3-0 nonabsorbable braided suture to perform a running simple suture in 1 direction to obtain a tension-free tenorrhaphy, followed by an RIHM corset-type suture using the same continuous strand in the opposite direction. Average time to surgery was 10 days (range, 3-33 d). Mean follow-up was 15 weeks (range, 10-26 wk). We applied the immediate controlled active motion protocol to all injuries except those in the thumb, where we used a dynamic extension protocol instead.

RESULTS

Using the criteria of Miller, all 9 tendon repairs achieved excellent or good results. There were no tendon ruptures or extensor lags. No patients required secondary surgery for tenolysis or joint release. No wound complications occurred.

CONCLUSIONS

The RIHM technique for primary extensor tendon repairs in zone IV and V and T1 to TIV is safe, allows for immediate controlled active motion in the fingers and an immediate dynamic extension protocol in the thumb, and achieves good to excellent functional outcomes. These clinical outcomes support prior biomechanical data.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.