Flexor tendon repair in zone 2 using a six-strand 'figure of eight' suture

My journey in hand surgery: combining patient care, clinical and basic science research

This review is about my clinical and research journey in hand surgery. The journey has been a worthwhile and meaningful one, especially when I felt there were areas I could influence management, whether this be rare cases, common conditions or where a suggested algorithm may be helpful. I also had the unique privilege of working with geneticists, which has resulted in clinical-pathological publications that could influence patient management, as shared from a clinician's perspective. It is hoped this article will inspire young clinician scientists to pursue a journey of collaboration with other researchers.

Comparison of 4 Different 4-Strand Core Suturing Techniques for Flexor Tendon Laceration: An Ex Vivo Biomechanical Study

BACKGROUND

Forces applied to the repaired flexor tendon should not exceed its yield force during early postoperative rehabilitation to prevent gapping and rupture. We aimed to biomechanically compare the tensile strengths and the 2-mm gapping of 4 different 4-strand core suturing techniques for flexor tendon repair.

METHODS

Fifty-six goat deep digital flexor tendons were repaired with the 4-strand double-modified Kessler, the 4-strand augmented Becker, the 4-strand Savage, and the 4-strand modified Tang techniques. All tendons were repaired with 4-0 polyester for core suture and 5-0 polyester for continuous epitendinous running suture. The specimens were subjected to static linear tensile testing by applying a single linear load-to-failure pull. After the linear load testing, the yield load, the ultimate strength of the repaired tendons, and the force exerted to yield a 2-mm gap were measured.

RESULTS

All peripheral sutures ruptured near the yield point. All core suture techniques were similar regarding the yield force. The augmented Becker 4-strand technique had the greatest ultimate strength (98.7 [82-125.3] N). The modified double Kessler technique was the weakest in resisting a 2-mm gap formation. The 4-strand modified Tang repair had the shortest (11.3 [7-15] minutes), while the 4-strand augmented Becker had the longest operative time (29 [23-33] minutes).

CONCLUSIONS

All 4 techniques demonstrated similar yield force, with differences in operative time, ultimate strength, and resistance to gapping. Future clinical studies can further elucidate their appropriateness for early active motion protocols.

Investigation of the effects of two-, four-, six- and eight-strand suture repairs on the biomechanical properties of canine gastrocnemius tenorrhaphy constructs

OBJECTIVE

To determine the effects of 2-, 4-, 6- and 8-strand suture repairs on the biomechanical properties of canine gastrocnemius tenorrhaphy constructs in an ex vivo model.

SAMPLE

56 cadaveric gastrocnemius musculotendinous units from 28 adult large-breed dogs.

PROCEDURES

Tendons were randomly assigned to 4 repair groups (2-, 4-, 6- or 8-strand suture technique; n = 14/group). Following tenotomy, repairs were performed with the assigned number of strands of 2-0 polypropylene suture in a simple interrupted pattern. Biomechanical testing was performed. Yield, peak, and failure loads, the incidence of 1- and 3-mm gap formation, forces associated with gap formation, and failure modes were compared among groups.

RESULTS

Yield, peak, and failure forces differed significantly among groups, with significantly greater force required as the number of suture strands used for tendon repair increased. The force required to create a 1- or 3-mm gap between tendon ends also differed among groups and increased significantly with number of strands used. All constructs failed by mode of suture pull-through.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that increasing the number of suture strands crossing the repair site significantly increases the tensile strength of canine gastrocnemius tendon repair constructs and their resistance to gap formation. Future studies are needed to assess the effects of multistrand suture patterns on tendon glide function, blood supply, healing, and long-term clinical function in dogs to inform clinical decision-making.

Rupture Rate, Functional Outcome and Patient Satisfaction after Primary Flexor Tendon Repair with the Modified 4-Strand Core Suture Technique by Tsuge and Using the Arthrex FiberLoop® with Early Motion Rehabilitation

PURPOSE

Our hypothesis was that the rupture rate after primary flexor tendon repair in the modified 4-strand core suture technique using the FiberLoop^® (Arthrex, Munich, Germany) is lower than in other suture materials and functional outcome and patient satisfaction are superior compared to the current literature.

PATIENTS AND METHODS

A 2-stage retrospective, randomized follow-up study of 143 patients treated with the Arthrex FiberLoop^® after flexor tendon injury in zones 2 or 3 from May 2013 to May 2017 was performed. In the 1^st stage, the rupture rate of all patients was assessed after a follow-up of at least one year by interview to exclude revision surgery. In the 2nd stage, 20% of the patients could be randomly clinically examined. Functional parameters, such as finger and wrist range of motion measured by goniometer, grip strength measured by Jamar dynamometer (Saehan, South Korea), patient satisfaction measured by school grades (1-6), pain levels measured by visual rating scales (0-10) and functional outcome according to the DASH-score were assessed. The Buck-Gramcko and Strickland scores were calculated. The length of sick leave was recorded.

RESULTS

A rupture rate of 2.1% was recorded. 29 patients (20%) were followed up at a mean of 34 ± 7.5 months postoperatively. 10.3% of these patients had an incomplete fingertip palm distance. The mean postoperative grip strength was 24 ± 3.1 kg. 93% of the patients were very satisfied with the treatment. No patient complained of pain postoperatively. The mean postoperative DASH score was 6.7 ± 2.8 points. The mean Buck-Gramcko score was 14 ± 0.2 points. 93% of the patients had excellent and 7% good results according to the Strickland score. 67% of patients had a work accident and returned to work at a mean of 4 ± 0.2 months postoperatively. 31% of patients suffered a non-occupational injury and returned to work at a mean of 3 ± 0.4 months postoperatively.

CONCLUSIONS

Primary flexor tendon repair in the modified 4-strand core suture technique using the Arthrex FiberLoop^® has proven to be a viable treatment option in our series. The rupture rate was lower than in other suture materials. It leads to acceptable pain relief, grip strength and functional outcome.

LEVEL OF EVIDENCE

IV; therapeutic.

Ex Vivo Biomechanical Assessment of a Novel Multi-Strand Repair of Canine Tendon Lacerations

OBJECTIVE

 This study aimed to evaluate the effect of increasing the number of suture strands traversing the transection site, level of suture purchase and depth of suture penetrance on the biomechanical properties of repaired gastrocnemius tendons.

STUDY DESIGN

 Thirty-eight adult cadaveric gastrocnemius tendons were randomized, transected and repaired with either two-, four- or six-strand locking multi-level repair. Tensile loads required to create a 1 and 3 mm gap, yield, peak and failure loads and failure mode were analysed. Significance was set at p < 0.05.

RESULTS

 Mean ± standard deviation yield, peak and failure force for six-strand repairs was 90.6 ± 22.1 N, 111.4 ± 15.2 N and 110.3 ± 15.1 N respectively. This was significantly greater compared with both four-strand (55.0 ± 8.9 N, 72.9 ± 7.8 N and 72.1 ± 8.2 N) and two-strand repairs (24.7 ± 8.3 N, 36.5 ± 6.0 N and 36.1 ± 6.3 N) respectively (p < 0.001). Occurrence of 3 mm gap formation was significantly less using six-strand repairs (p < 0.001). Mode of failure did not differ between groups with all repairs (36/36; 100%) failing by suture pull-through.

CONCLUSION

 Pattern modification by increasing the number of suture strands crossing the repair site, increasing points of suture purchase from the transection site and depth of suture penetrance is positively correlated with repair site strength while significantly reducing the occurrence of gap formation in a canine cadaveric model. Additional studies in vivo are recommended to evaluate their effect on tendinous healing, blood supply and glide resistance prior to clinical implementation.

Estudo biomecânico in vitro das suturas em “oito” e de Kessler de tendões flexores de porcos

Objetivo Avaliar as propriedades biomecânicas dos pontos de sutura tendinosa em “oito” e de Kessler.

Métodos Tendões flexores dos dedos de membros superiores de porcos foram divididos em dois grupos com suturas triplas centrais em “oito” (seis passagens) e de Kessler (duas passagens) associadas a suturas periféricas contínuas simples, e submetidos a ensaios mecânicos longitudinais contínuos, obtendo-se as propriedades mecânicas de carga máxima e de energia na carga máxima.

Resultados As médias da carga máxima e da energia na carga máxima na sutura em “8” foram de 63,4 N e 217,3 Nmm, respectivamente; na sutura de Kessler, os valores foram de 34,19 N e 100,9 Nmm, respectivamente. A análise estatística indicou que o ponto em “oito” é superior mecanicamente ao ponto de Kessler.

Conclusões Nas condições deste experimento e no tendão flexor de dedo de membro superior de porcos, o triplo ponto em “oito” (seis passagens) é mais resistente do que o ponto de Kessler (duas passagens). O triplo ponto em “oito”, com seis passagens, permite movimentação ativa na reabilitação imediata de reparo de tendão flexor de dedo de membro superior com pouco risco de ruptura ou espaçamento na sutura.

A Review and Meta-analysis of Adverse Events Related to Local Flap Reconstruction for Digital Soft Tissue Defects

We reviewed the current literature to estimate incidence rates for adverse events with pedicled flaps in the hand. We identified 241 different studies reporting adverse events for 6693 flaps. The average incidence rate was 5.4% and total or partial loss of flap constituted 65% of all reported complications. Flaps with reverse or perforator-based flow may be more prone to vascular complications compared with flaps with antegrade flow or skin pedicle. The incidence rates were acceptable in all flaps (1%-10%) and thus the flap can be chosen primarily based on considerations other than risk of adverse events.

The effect of adding active flexion to modified Kleinert regime on outcomes for zone 1 to 3 flexor tendon repairs. A prospective randomized trial

In a prospective randomized study, we studied whether adding active flexion to a modified Kleinert regime changed outcomes of flexor tendon repairs in zone 1, 2 and 3 in 73 fingers (53 patients). Evaluation included active range of finger motion, grip and pinch strengths. Twelve months after surgery, the increase in range of active finger motion after adding active flexion was insignificant compared with that with the modified Kleinert regime. According to the Strickland criteria, 20 out of 29 fingers had excellent or good recovery after adding active flexion, as did 28 out of 34 fingers with the modified Kleinert regime; we could not detect significant improvement of the good and excellent rate. At 6 months, the pinch strength was significantly higher with the addition of active flexion. We failed to find that adding active finger flexion to the modified Kleinert regime improves the overall long-term results of repairs in zone 1 to 3, though recovery appeared faster, and the good and excellent recovery of zone 2 repairs was 17% greater with the active flexion protocol.

LEVEL OF EVIDENCE

I.

Augmented and virtual reality in surgery-the digital surgical environment: applications, limitations and legal pitfalls

The continuing enhancement of the surgical environment in the digital age has led to a number of innovations being highlighted as potential disruptive technologies in the surgical workplace. Augmented reality (AR) and virtual reality (VR) are rapidly becoming increasingly available, accessible and importantly affordable, hence their application into healthcare to enhance the medical use of data is certain. Whether it relates to anatomy, intraoperative surgery, or post-operative rehabilitation, applications are already being investigated for their role in the surgeons armamentarium. Here we provide an introduction to the technology and the potential areas of development in the surgical arena.

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.

A biomechanical study of pediatric flexor profundus tendon repair. Comparing the tensile strengths of 3 suture techniques

Objectives:

To investigate the tensile strength of repaired flexor profundus tendons in young lambs, which would be equivalent to repairs in children older than 2 years of age.

Methods:

A comparative in-vitro experimental study conducted at King Saud University, Riyadh, Kingdom of Saudi Arabia from October 2014 to December 2015. We utilized 30 flexor profundus tendons of young lambs with a width of 4 mm. All tendons were repaired with a 4-strand repair technique using 4/0 polypropylene core sutures. In group I (n=10 tendons), 2 separate figure-of-eight sutures were applied. In group II (n=10 tendons), simple locking sutures were added to the corners of 2 separate figure-of-eight sutures. In group III (n=10 tendons), the locked cruciate repair was used. All tendon repairs were tested to single-cycle tensile failure.

Results:

There was no significant difference between groups II and III with regards to gap and breaking forces; and all forces of these 2 groups were significantly higher than the forces in group I.

Conclusion:

It was concluded that 4 mm-wide pediatric flexor tendons allow a 4-strand repair and the use of 4/0 sutures. The use of locking sutures increases the tensile strength to values that may allow protective mobilization in children.

Comparison of Flexor Tendon Suture Techniques Including 1 Using 10 Strands

PURPOSE

To compare mechanical properties of a multistrand suture technique for flexor tendon repair with those of conventional suture methods through biomechanical and clinical studies.

METHODS

We describe a multistrand suture technique that is readily expandable from 6 to 10 strands of core suture. For biomechanical evaluation, 60 porcine flexor tendons were repaired using 1 of the following 6 suture techniques: Kessler (2-strand), locking cruciate (4-strand), Lim/Tsai's 6-strand, and our modified techniques (6-, 8-, or 10-strand). Structural properties of each tenorrhaphy were determined through tensile testing (ultimate failure load and force at 2-mm gap formation). Clinically we repaired 25 flexor tendons using the described 10-strand technique in zones I and II. Final follow-up results were evaluated according to the criteria of Strickland and Glogovac.

RESULTS

In the biomechanical study, tensile properties were strongly affected by repair technique; tendons in the 10-strand group had approximately 106%, 66%, and 39% increased ultimate load to failure (average, 87 N) compared with those in the 4-, 6-, and 8-strand groups, respectively. Tendons in the 10-strand group withstood higher 2-mm gap formation forces (average, 41 N) than those with other suture methods (4-strand, 26 N; 6-strand, 27 N; and 8-strand, 33 N). Clinically, we obtained 21 excellent, 2 good, and 2 fair outcomes after a mean of 16 months (range, 6-53 mo) of follow-up. No patients experienced poor results or rupture.

CONCLUSIONS

The 10-strand suture repair technique not only increased ultimate strength and force at the 2-mm gap formation compared with conventional suture methods, it also showed good clinical outcomes. This multistrand suture technique can greatly increase the gap resistance of surgical repair, facilitating early mobilization of the affected digit.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Evidence-based flexor tendon repair

The goal of flexor tendon repair is to achieve normal range of motion of the finger or thumb. The surgical approach depends on the level of injury. Multistrand core suture repairs are recommended for primary flexor tendon repair. It is evident that at least 4 strands are required to an initiate and active range of motion protocol. The epitendinous suture can also increase the strength of the repair. Careful attention to the post-operative therapy regiment is critical to a successful repair.

A systematic review of 2-strand versus multistrand core suture techniques and functional outcome after digital flexor tendon repair

PURPOSE

To determine published evidence to evaluate the hypothesis that multistrand techniques result in a poorer outcome than 2-strand techniques for digital flexor tendon repairs.

METHODS

A systematic review was undertaken to compare outcomes and rupture rates between 2-strand and multistrand core sutures in digital flexor zones 2 to 5. Outcome was measured by the American Society for Surgery of the Hand criteria, original or modified Strickland criteria, or Buck-Gramcko criteria.

RESULTS

A total of 1,878 patients (2,585 digits; 3,749 tendons) were included from the selected studies. Thirty-three studies reported 2-strand repairs and 15 reported multistrand repairs. Of the total tendon injuries, 59% were flexor digitorum profundus, 38% were flexor digitorum superficialis, and 2% were flexor pollicis longus. The pooled rupture rate was 3.9 per 100 digits. No significant difference was detected between 2-strand and multistrand repairs for outcomes by all measures or rupture rate.

CONCLUSIONS

Because of the wide variation in reporting of outcomes and study design on which this analysis was based, we cannot definitively confirm our hypothesis. We present the standards for outcomes as well as rupture rate for digital flexor tendon repair.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

The search for the ideal tendon repair in zone 2: strand number, anchor points and suture thickness

This review article examines the mechanical factors involved in tendon repair by sutures. The repair strength, repair stiffness and gap resistance can be increased by increasing the number of core strands and anchor points, by increased anchor point efficiency and the use of peripheral sutures, and by using thicker sutures. In the future, laboratory tests could be standardized to a specific animal model and to a defined cyclic motion programme. Clinical studies support the use of multi-strand core and peripheral sutures, but two-strand core sutures are not adequate to ensure consistently good clinical results. Training surgeons in complex tendon repair techniques is essential.

Flexor tendon injuries in the child

This review aims to highlight the differences in the management of flexor tendon injuries between children and adults. These include differences in epidemiology, anatomy, classification, diagnosis, incisions and skin closure, the size of the flexor tendons, technical aspects of zones I and II repairs, core suture purchase length, rehabilitation, results, and complications of primary flexor tendon repair. Finally, one- versus two-stage flexor tendon reconstruction in children is reviewed.

Recent developments in flexor tendon repair techniques and factors influencing strength of the tendon repair

Over the last decade, both basic researchers and surgeons have sought to identify the most appropriate techniques to be applied in flexor tendon repairs. Recent developments in experimental tendon repairs and clinical outcomes of newer repair techniques have been reviewed in an attempt to comprehensively summarize the most critical mechanical factors affecting the performance of tendon repairs and the surgical factors influencing clinical outcomes. Among them, attention to annular pulleys, the purchase and tension of the core suture, and the direction and curvature of the path of tendon motion have been found to be determining factors in the results of tendon repair.

Clinical use of a combined grasping and locking core suture technique for flexor tendon repair in zone II

Previous authors have used either a grasping or a locking technique for flexor tendon repair in zone II. A combined (grasping and locking) 10-strand repair was used by the author in 22 adults (n = 28 fingers) with lacerations of both flexor tendons in zone II. The combined repair is known to be strong (mean tensile strength of 164 N), and the technique was used in selected cases who were thought to be at higher risk of rupture either because of excessive digital oedema (in early tendon repairs) or because of tendon retraction (in late primary tendon repairs). The 10-strand repair was bulky and, hence, only the profundus tendon was repaired; and "venting" of the pulley system was done proximal to the repair site as recommended by other authors. Supervised early active mobilisation was done immediately after the operation. At final follow-up, the outcome was calculated using the original Strickland-Glogovac grading system. There were no ruptures and the final outcome was considered excellent in 19 patients (n = 25 fingers), good in two patients (n = 2 fingers), and fair in the remaining patient (n = 1 finger). It was concluded that the bulky 10-strand repair may be used for zone II finger flexor tendon lacerations as long as a profundus-(?) only repair and "venting" of the pulley system are performed.

Primary flexor tendon surgery: the search for a perfect result

Repair of the divided flexor tendon to achieve normal, or near normal, function is an unsolved problem, with each result still uncertain. The authors believe the way forward in primary flexor tendon surgery clinically is by use of strengthened but simpler sutures, appropriate venting of the pulley system, and maintaining early rehabilitation. However, there needs also be consideration of patient factors and other aspects. Research needs to continue more widely, in both the laboratory and the clinical environment, to find ways of better modifying adhesions after surgical repair of the tendon.

Suture purchase length: a biomechanical study of flexor tendon repair in newborn lambs

PURPOSE

We aimed to determine the effect of core suture purchase on repair strength of flexor tendon lacerations in newborn lambs as a model for pediatric tendon repairs. The dimensions of flexor tendons in these lambs are similar to those of children younger than 2 years.

METHODS

Thirty-six flexor tendons were harvested from newborn lambs. The tendons were cut transversely and repaired using a single figure-of-eight core suture using 5-0 polypropylene. The 36 tendons were divided into 9 groups (n = 4 tendons in each group) according to the length of the core suture purchase: 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm. The initial gap force and ultimate strength of the repairs were studied using a computerized tensometer.

RESULTS

There were no significant differences between core suture purchase lengths 2, 3, 4, and 5 mm for both initial gap and ultimate strength. Similarly, there were no significant differences between purchase lengths 6, 7, 8, 9, and 10 mm for both initial gap and ultimate strength. However, there was a significant difference between the former and the latter groups.

CONCLUSIONS

The optimal core suture purchase length in flexor tendon repair of newborn lambs was 6 mm. However, this length may be too much of a purchase when applied clinically in children younger than 2 years.

Simplifying four-strand flexor tendon repair using double-stranded suture: a comparative ex vivo study on tensile strength and bulking

We have compared a simple four-strand flexor tendon repair, the single cross-stitch locked repair using a double-stranded suture (dsSCL) against two other four-strand repairs: the Pennington modified Kessler with double-stranded suture (dsPMK); and the cruciate cross-stitch locked repair with single-stranded suture (Modified Sandow). Thirty fresh frozen cadaveric flexor digitorum profundus tendons were transected and repaired with one of the core repair techniques using identical suture material and reinforced with identical peripheral sutures. Bulking at the repair site and tendon-suture junctions was measured. The tendons were subjected to linear load-to-failure testing. Results showed no significant difference in ultimate tensile strength between the Modified Sandow (36.8 N) and dsSCL (32.6 N) whereas the dsPMK was significantly weaker (26.8 N). There were no significant differences in 2 mm gap force, stiffness or bulk between the three repairs. We concluded that the simpler dsSCL repair is comparable to the modified Sandow repair in tensile strength, stiffness and bulking.

A six-strand technique for zone II flexor-tendon repair in children younger than 2 years of age

INTRODUCTION

A six-strand repair for zone II flexor-tendon repair in children younger than 2 years of age has not been reported in the literature because of the small size of the flexor tendon in this very young age group.

PURPOSE

The aim is to introduce the use of a six-strand repair in zone II flexor-tendon repair in children younger than 2 years of age.

METHODS

A total of 12 children younger than 2 years, with 12 injured fingers, were treated over a 10-year period. A 'profundus only' repair was done using three separate 'figure of eight' core sutures and a continuous epitendinous suture. The repair site was bulky and 'venting' of the pulley system proximal to the repair site was done. The hand was immobilised for 3.5 weeks after surgery and then physiotherapy exercises were started. The final net range of motion at the interphalangeal joints was measured and the outcome was assessed as per the Strickland-Glogovac criteria.

RESULTS

There were no ruptures. The final outcome in range of motion was excellent in nine children and good in the remaining three children. None of the children required tenolysis.

CONCLUSION

Our six-strand technique is an alternative technique for zone II flexor-tendon repair in children younger than 2 years of age, but the bulky repair site requires a 'profundus only' repair and 'venting' of the pulley system.

A biomechanical study of flexor tendon repair in zone II: comparing a combined grasping and locking core suture technique to its grasping and locking components

INTRODUCTION

All previous experimental and clinical repairs of flexor tendons in zone II have used either a grasping or a locking technique. In this article, a combined (grasping and locking) repair was compared biomechanically to its grasping and locking components.

METHODS

Using fresh flexor profundus adult sheep tendons, three techniques of tendon repair were tested biomechanically: the 'three figure-of-eight sutures' (a six-strand grasping technique), the 'locked cruciate repair' (a four-strand locked technique) and the 'combined technique' (a 10-strand repair using both the figure-of-eight and cruciate sutures). All repairs were tested to single-cycle tensile failure using a computerised tensometer. For each repair, the 2-mm gap force and the ultimate breaking (failure) force were recorded.

RESULTS

Biomechanically, the combined repair was found to be the strongest regarding both gap and failure (P<0.025; two-tailed by the Mann-Whitney test).

CONCLUSION

The combined 10-strand repair is stronger biomechanically than its grasping and locking components.

Finger zone II flexor tendon repair in children (5-10 years of age) using three 'figure of eight' sutures followed by immediate active mobilization

For children between 5-10 years of age with zone II flexor tendon lacerations, the literature recommends a modified early mobilization programme under the supervision of a hand therapist but the fingers are immobilized between physiotherapy sessions. We report on a series of children between 5-10 years of age with flexor tendon lacerations (n = 54 fingers) in zone II repaired with a six-strand core suture (three separate 'figure of eight' sutures) and actively mobilized immediately after surgery similar to adult rehabilitation programmes with no immobilization between the physiotherapy sessions. The average follow-up for the study group was 13 months (range 7-25 months). There were no ruptures. The final outcome was excellent in 46 fingers (85%) and good in the remaining eight fingers (15%) using the Strickland-Glogovac criteria.

Zone 2 lacerations of both flexor tendons of all fingers in the same patient

Over an eight-year period, the author has treated five males (mean age of 31 years) with clean-cut zone 2 lacerations of both flexor tendons of all fingers using the same surgical technique (profundus only repair using three 'figure of eight' core sutures and proximal venting of the pulley system) and the same postoperative mobilization programme (a dorsal blocking splint with immediate active motion that allowed full extension at the interphalangeal joints). There were no ruptures of the repaired 20 fingers. At final follow-up (mean of 22 months after surgery), the outcome was considered excellent in 12 fingers, good in four fingers and fair in the remaining four fingers by the Strickland-Glogovac criteria. The outcome was similar in all four fingers for every patient supporting the hypothesis of previous studies that the outcome of repair of clean-cut flexor tendon lacerations in zone 2 is related to the psychological and biologic characteristics of the patient.

Isolated flexor digitorum profundus tendon injuries in zones IIA and IIB repaired with figure of eight sutures

The 'figure of eight' suture technique for flexor tendon repair is known to be simple and strong but it has the major disadvantage of being bulky, with the knots outside the repair site. When the superficialis tendon is intact it may cause impingement and/or increase the work of flexion with postoperative mobilization and it is not known whether this bulky repair is suitable for isolated profundus injuries in zone II. A series of 36 patients (36 fingers) with clean-cut isolated flexor digitorum profundus tendon injuries in zones IIA/IIB were reviewed retrospectively. Repairs were done with three 'figure of eight' sutures and the pulleys proximal to the tendon laceration level were vented. Postoperatively, early active exercises were carried out. There were no ruptures. At a mean final follow-up of 6 months, the outcome (in range of motion) was excellent in 27 fingers and good in the remaining nine fingers by the Strickland criteria. It was concluded that the bulky 'figure of eight' technique can be used in isolated profundus tendon injuries in zones IIA/IIB.

Flexor tendon repair in zone III

There is a paucity of the literature on the outcome of zone III flexor tendon injuries. In this paper, we report on the results of zone III flexor tendon repair in 35 consecutive adult patients with clean cut lacerations of both flexor tendons in 42 fingers. There were 25 men and 10 women with an average age of 32 years. Repair of both flexor tendons was performed using 'figure of eight' core sutures and a continuous epitendinous suture. Postoperatively, an immediate active range of motion protocol was applied to ensure full active extension of the interphalangeal joints. The results were assessed using the Strickland-Glogovac grading system. There were no ruptures. One patient with two injured fingers developed complex regional pain syndrome and the final outcome was fair in both fingers. In the remaining 34 patients (40 fingers), 33 patients (38 fingers) had an excellent outcome and the remaining patient (two fingers) had a good outcome.

A new technique of flexor profundus repair in the distal part of zone I: inclusion of the palmar plate

Flexor profundus lacerations in the distal part of zone I are usually treated by tendon reinsertion into bone. We present a modified technique in which three 'figure of eight' sutures include the palmar plate in the distal purchase. Inclusion of the palmar plate significantly strengthens the tensile strength of the repair and this was confirmed biomechanically in an experimental study. In a prospective clinical study, 15 patients with clean-cut complete lacerations of the profundus tendon in the distal part of zone I underwent the modified repair technique of three separate 'figure of eight' sutures with the palmar plate included in the suture distally and 7 mm suture purchase proximally, with postoperative immediate active motion that ensured full active extension of the interphalangeal joints. There were no ruptures or infections. At final follow-up 12-25 weeks after surgery, the mean range of motion at the distal, proximal, and combined interphalangeal joints was 66 degrees, 100 degrees and 166 degrees respectively. All patients achieved an excellent or good outcome.

The effects of core suture purchase on the biomechanical characteristics of a multistrand locking flexor tendon repair: a cadaveric study

PURPOSE

To determine the effects of suture purchase on work of flexion (WOF), 2-mm gap force, and load to failure on the combination cross-locked cruciate-interlocking horizontal mattress (CLC-IHM) flexor tendon repair in zone II.

METHODS

A total of 33 fresh-frozen cadaveric fingers were mounted in a custom jig, and the flexor digitorum profundus of each finger was fixed to the mobile arm of a tensile strength machine. Initial measurements of WOF were obtained. Each tendon was repaired with the CLC core suture, randomly assigned to placement of 3, 5, 7 or 10 mm from the cut edge of the tendon, and completed with the IHM circumferential suture. After the repair was completed, measurements of WOF were repeated. Each finger was cycled 1000 times. After each 250 cycles, gapping was recorded, and WOF was measured again. Change in WOF (WOF after repair - WOF of intact tendon) was calculated. Tendons were then dissected from the fingers and linearly tested for 2-mm gap force and ultimate load to failure.

RESULTS

The group repaired at 10 mm had the lowest percent increase in WOF (5.2%), the highest 2-mm gap force (89.8 N), and the highest ultimate load to failure (111.5 N). The group repaired at 3 mm had the highest percent increase in WOF (22.1%), the lowest 2-mm gap force (54.6 N), and the lowest ultimate load to failure (84.6 N).

CONCLUSIONS

A 10-mm suture purchase is the recommended distance for optimal performance for the CLC-IHM combination repair method. This method with a 10-mm suture purchase has a low increase in WOF, high strength, and high resistance to gapping, and it should be strong enough to tolerate early motion.