Mechanical strength of the side-to-side versus Pulvertaft weave tendon repair

New dynamic suture material for tendon transfer surgeries in the upper extremity - a biomechanical comparative analysis

BACKGROUND

Early mobilization after tendon surgery is crucial to avoid commonly observed postoperative soft tissue adhesions. Recently, a new suture was introduced (DYNACORD; DC) with a salt-infused silicone core designed to minimize laxity and preserve consistent tissue approximation in order to avoid gap formation and allow early mobilization.

AIMS

To compare the biomechanical competence of DC against a conventional high strength suture (FiberWire; FW) in a human cadaveric tendon transfer model with an early rehabilitation protocol.

METHODS

Sixteen tendon transfers (flexor digitorum superficialis (FDS) IV to flexor pollicis longus (FPL)) were performed in 8 pairs human cadaveric forearms using either DC or FW. Markings were set 0.8 cm proximally and 0.7 cm distally to the level of the interweaving zone of the transfer. All specimens underwent repetitive thumb flexion against resistance in 9 intermittent series of 300 cycles each, simulating an aggressive postoperative rehabilitation protocol. After each series, the distance of the proximal marker to the interweaving zone (proximal), the length of the interweaving zone (intermediate) and the distance of the distal marker to the interweaving zone (distal) were measured.

RESULTS

Pooled data over all nine series, normalized to the immediate postoperative status, demonstrated no significant differences between FW and DC (p ≥ 0.355) for the proximal and distal markers. However, at the intermediate zone, DC was associated with significant length shortening (p < 0.001) compared to FW without significant length changes (p = 0.351). Load to catastrophic failure demonstrated significant higher forces in FW (p = 0.011). Nevertheless, due to failure mainly proximal or distal of the transfer zone, these loads are not informative.

CONCLUSION

From a biomechanical perspective, DC preserved tissue approximation and might be considered as a valid alternative to conventional high-strength sutures in tendon transfer surgery. DC might allow for a shorter interweaving zone and a more aggressive early postoperative rehabilitation program, possibly avoiding commonly observed postoperative soft tissue adhesions and stiffness.

The Effect of an Additional Core Suture During Pulvertaft Tendon Repair: A Fresh-Frozen Cadaver Study

PURPOSE

Pulvertaft tendon repair is a strong suture technique; however, proper tendon tension is impaired by repair site elongation. Therefore, methods to reduce postoperative elongation are warranted. This study aimed to determine the effects of additional core sutures during Pulvertaft tendon repair on repair site elongation and rupture strength.

METHODS

A total of 48 finger extensor tendons were harvested from fresh-frozen cadavers, and tendons with similar diameters were paired. The 24 pairs of tendons were divided into the following 4 groups: group I, 3 interlaced weaves only; group II, 3 interlaced weaves and 2 core suture strands with 4-0 nylon; group III, 3 interlaced weaves and 2 core suture strands with 4-0 FiberWire; and group IV, 4 interlaced weaves only. Each sutured tendon was placed in a Universal Testing Machine, and repair site elongation after repeated traction loads and rupture strength were measured.

RESULTS

The mean elongation values were 2.74 ± 0.84 mm, 1.80 ± 0.16 mm, 1.60 ± 0.18 mm, and 1.92 ± 0.18 mm for groups I, II, III, and IV, respectively. The elongation values were significantly lower in groups II, III, and IV than in group I. The mean rupture strengths were 64.9 ± 16.0 N, 94.8 ± 17.2 N, 110.9 ± 21.3 N, and 104.9 ± 17.5 N for groups I, II, III, and IV, respectively. Rupture strengths were significantly higher for groups III and IV than for group I.

CONCLUSIONS

After adding core sutures during Pulvertaft tendon repair, the elongation amount decreased, and the rupture strength improved.

CLINICAL RELEVANCE

The study showed the effect of additional core sutures during Pulvertaft tendon repair, suggesting that it could be useful in reducing postoperative tendon elongation when extensor tendon transfers are performed.

The minimum required overlap length for tendon transfer A biomechanical study on human tendons

In tendon transfer surgeries sufficient stability of the tenorrhaphy is essential. In addition to the choice of a suitable technique, adequate overlap of donor and recipient tendons must be ensured. The aim of this study was to investigate the tensile strength with regard to tendon overlap of a recently published tenorrhaphy, termed Woven-Fridén (WF) tenorrhaphy, which displayed higher tensile strength and lower bulk when compared to the established Pulvertaft technique. For this purpose, WF tenorrhaphies with 1.5 cm, 2 cm, and 3 cm tendon overlap were performed and subsequently tested for different biomechanical properties by tensile testing. Among others, the parameters of ultimate load and stiffness were collected. Native tendons served as controls. A formula was derived to quantify the relation between tendon overlap and ultimate load. We observed that sufficient tensile strength (mean ultimate load of 217 N) is already given with a 2 cm tendon overlap. In addition, with more than 3 cm overlap length only little additional tensile strength is to be expected as the calculated ultimate load of 4 cm overlap (397 N) is approaching the plateau of the maximal ultimate load of 435 N (native tendons).

Tendon Transfers: Techniques to Minimize Complications

Outcomes after tendon transfer to restore upper extremity function can be optimized using a standardized, multidisciplinary approach to the patient preoperatively, augmented intraoperative decision-making, and an early postoperative mobilization therapy protocol.

Republication of "Peroneus Brevis Tenodesis: Side-to-Side or Weave?"

Background

Inversion ankle injuries are extremely common, sometimes causing injury to the peroneus brevis tendon. If more than 50% of the tendon is injured, it oftentimes requires tenodesis to the adjacent peroneus longus tendon. Both Pulvertaft (PT) and side-to-side (SS) techniques have been used for joining the 2 tendons. The purpose of this study was to compare the strength and stiffness of these 2 techniques.

Methods

Five matched pairs of cadaver ankle specimens were randomized to receive either an SS or PT tenodesis of the peroneus brevis to longus tendons. Following the tenodesis, the specimens were tested for failure load, displacement, energy absorbed at failure, and peak load. Stiffness was also calculated. Paired t tests were performed to detect differences between the 2 conditions.

Results

There were no statistically significant differences between the SS and PT tenodesis for any of the metrics measured. For stiffness, the techniques were very similar (SS = 10.14 [4.35], PT = 12.85 [1.72]).

Conclusion

There is no difference in failure load, displacement, energy absorbed at failure, peak load or stiffness between the PT and SS techniques for peroneal tenodesis.

Level of Evidence

Level V, cadaver study.

Alternative Tendon Coaptations to the Pulvertaft Weave Technique: A Systematic Review and Meta-Analysis of Biomechanical Studies

BACKGROUND

The Pulvertaft weave technique (PT) is frequently used during tendon repairs and transfers. However, this technique is associated with limitations. In this systematic review and meta-analysis, quantitative and qualitative analyses were performed on in vitro, biomechanical studies that compared the PT with alternative techniques.

METHODS

Articles included for qualitative and/or qualitative analysis were identified following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies included in the meta-analysis were analyzed either as continuous data with inverse variance and random effects or as dichotomous data using a Mantel-Haenszel analysis assuming random effects to calculate an odds ratio.

RESULTS

A comprehensive electronic search yielded 8 studies meeting inclusion criteria for meta-analysis. Two studies with a total of 65 tendon coaptations demonstrated no significant difference in strength between the PT and traditional side-to-side (STS) techniques (P = .92). Two studies with a total of 43 tendon coaptations showed that the STS with 1 weave has a higher yield strength than the PT (P = .03). Two studies with a total of 62 tendon repairs demonstrated no significant difference in strength between the PT and the step-cut (SC) techniques (P = .70). The final 2 studies included 46 tendon repairs and demonstrated that the wrap around (WA) technique has a higher yield strength than the PT (P < .001).

CONCLUSIONS

The STS, SC, and WA techniques are preferred for improving tendon form. The STS and WA techniques have superior yield strengths than the PT, and the SC technique withstands similar stress to failure as the PT.

Biomechanical Strength of a Novel Tendon Splicing Open Book Technique Compared to the Pulvertaft Method Using Unembalmed Human Cadaveric Tissue

Background: Extensor pollicis longus (EPL) tendon rupture is a known complication of distal radius fractures. The Pulvertaft graft technique is currently used for tendon transfer of extensor indicis proprious (EIP) to EPL. This technique can produce unwanted tissue bulkiness and cosmetic concerns as well as hinder tendon gliding. A novel "open book" technique has been proposed, but relevant biomechanical data are limited. We designed a study to examine the biomechanical behaviours of the "open book" versus Pulvertaft techniques. Methods: Twenty matched forearm-wrist-hand samples were harvested from 10 fresh frozen cadavers (2 female, 8 male) with a mean age of 61.7 (±19.25) years. The EIP was transferred to EPL using the Pulvertaft versus "open book" techniques for each matched pair (sides randomly assigned). The repaired tendon segments were mechanically loaded using a Materials Testing System to examine graft biomechanical behaviours. Results: Mann-Whitney U test outcomes demonstrated that there was no significant difference between "open book" versus Pulvertaft techniques for peak load, load at yield, elongation at yield, or repair width. The "open book" technique demonstrated a significantly lower elongation at peak load and repair thickness, as well as significantly higher stiffness when compared with the Pulvertaft technique. Conclusions: Our findings support the use of the "open book" technique, producing comparable biomechanical behaviours compared to the Pulvertaft technique. Incorporating the "open book" technique potentially requires smaller repair volume, producing size and appearance that is more anatomic when compared with the Pulvertaft.

Pronator teres nerve branch transfer to the extensor carpi radialis brevis nerve branch for wrist extension reconstruction in proximal radial nerve injury following humeral shaft fractures

Background

Tendon and nerve transfers are used for functional reconstruction in cases of proximal radial nerve injury complicated by humeral fractures in patients who do not show functional recovery after primary nerve repair. The effectiveness of pronator teres (PT) nerve branch transfer to the extensor carpi radialis brevis (ERCB) nerve branch for wrist extension reconstruction was investigated and compared to the results of tendon transfer.

Methods

This study included 10 patients with proximal radial nerve injury, who did not show functional recovery after primary nerve repair at our hospital between April 2016 and May 2019. The nerve transfer procedure included PT nerve branch transfer to the ECRB nerve branch to restore wrist extension and the flexor carpi radialis (FCR) nerve branch to the posterior interosseous nerve (PIN) to restore thumb and finger extension. Tendon transfer procedures included PT transfer to the ECRB for wrist extension, FCR transfer to the extensor digitorum communis (EDC) for finger extension and palmaris longus (PL) transfer to the extensor pollicis longus (EPL) for thumb extension.

Results

Five patients recovered Medical Research Council grade M4 muscle strength in the ECRB and EPL in both tendon and nerve groups. Two patients recovered grade M3 strength and three patients recovered grade M4 strength in the EDC in the tendon transfer group, and all five patients recovered grade M4 strength in the EDC in the nerve transfer group. Limited wrist flexion was observed only in one patient in the tendon transfer group.

Conclusion

PT nerve branch transfer to the ECRB nerve branch combined with FCR nerve branch transfer to PIN is a useful strategy for wrist and fingers extension reconstruction in patients with proximal radial nerve injuries.

Teamwork Pays! Ten Tips for a Great Surgeon-Scientist Collaboration

This review represents our summary of what makes a great collaboration between a surgeon and a scientist. At first, with no perspective, such a collaboration seems easy and natural. But as time goes on, with more perspective, you realize how special it is. Now, in our 60s, with approximately 35 years of collaboration and 75 coauthored papers (most of them in The Journal of Hand Surgery), we are thankful and humbled for this tremendously fruitful and, importantly, enjoyable collaboration. We are not so foolish to think that we made this great collaboration-it was a gift. However, we now recognize many characteristics that make it great and have developed the following 10 tips.

Optimizing the Pulvertaft Weave Technique: A Comprehensive Systematic Review of Comparative Biomechanical Studies

PURPOSE

The Pulvertaft weave continues as a staple technique for tendon coaptations. Many have proposed minor alterations to the original technique to improve its strength, though a lack of consensus exists. Our aim was to explore how the number of weaves and suture characteristics contribute to the overall strength of the coaptation.

METHODS

A comprehensive electronic search was conducted using PubMed, Cochrane Library, and Scopus. Criteria for inclusion consisted of cadaveric human or animal biomechanical studies evaluating ultimate failure load (Newtons, N) as well as number of weaves, suture characteristics, tendon source, and number of coaptations. Weaves with minimum averages of 75 N were deemed successful, and those with >120 N were considered high performing.

RESULTS

A total of 347 tendon transfers from 15 studies met inclusion criteria. Average strength by number of weaves was 36.4 N (n=52) for 1 weave; 54.2 N (n=58) for 2 weaves; 115.9 N (n=174) for 3 weaves; and 81.7 N (n=63) for 4 weaves. Statistical differences were observed between 1 and 2 weaves (p<0.0001); 2 and 3 weaves (p<0.0001); 3 and 4 weaves (p<0.003); and 2 and 4 weaves (p<0.0001). High performing tendon transfers utilized 3 weaves, 3-0 or 4-0 braided sutures, and figure-of-eight or mattress core sutures.

CONCLUSIONS

Contrary to the current dogma of 'the more the better', our findings show that Pulvertaft weave strength is optimized when 3 weaves are used to combine donor and recipient tendons. Braided sutures with either figure-of-eight or mattress sutures were associated with highest strength of repair.

Biomechanical Comparison of a Horizontal Mattress, Cross Suture and Vertical Mattress for Repair of a Tendon Weave in a Porcine Model

Background: An effective suture method enables early active motion exercises and optimal post-surgical outcomes. The aim of this study is to evaluate the tensile strength of three suture configurations – horizontal mattress (HM), vertical mattress (VM) and a cross suture for repair of a tendon weave. We hypothesised that the direction of mattress sutures relative to the tendon fibres would affect the tensile strength of tendon repair.

Methods: Using porcine flexor tendons and the same number of surgical sutures, three tendon weave constructs differing in the method of suture were compared: HM suture configuration (conventional technique), cross-stitch (CS) configuration (conventional technique) and VM suture configuration (novel technique). Ten pairs of each group were mounted in a material testing machine and subjected to a simple tensile test and a cyclic loading test for their biomechanical comparison.

Results: The VM group and CS group had significantly higher ultimate failure load, linear stiffness and fatigue strength as compared to the HM group. The failure mode was suture breakage or tendon rupture for the VM and the CS group, while the suture pullout of the tendon only occurred in the HM group.

Conclusion: Among the three techniques used for repair of a tendon weave, the VM suture technique was demonstrated to have the greatest tensile strength and least associated with suture pull-out. The direction of the mattress suture in relation the direction of tendon fibres affects the strength of repair.

Finding the Optimal Surgical Incision Pattern-A Biomechanical Study

The closure of wounds and subsequent optimal wound healing is essential to any successful surgical intervention. Especially on parts of the body with limited possibilities for local reconstruction, optimal distribution of load is essential. The aim of the present study was therefore to examine three different incision patterns, conventional straight, Lazy-S and Zigzag, with regard to their biomechanical stability and mode of failure on a porcine skin model. Our results demonstrate the superior biomechanical stability of Lazy-S and Zigzag incision patterns with perpendicular suture placement. This holds true, in particular, for Zigzag incisions, which showed the highest values for all parameters assessed. Moreover, the observed superior stability of Lazy-S and Zigzag incision patterns was diminished when sutures were placed in tensile direction. The conventional straight incision represents the standard access for a large number of surgical procedures. However, we were able to demonstrate the superior biomechanical stability of alternative incision patterns, in particular the Zigzag incision. This is most likely caused by an improved distribution of tensile force across the wound due to the perpendicular placement of sutures. Moreover, this technique offers additional advantages, such as a better overview of the operated area as well as several cosmetic improvements. We therefore advocate that the surgeon should consider the use of a Zigzag incision over a conventional straight incision pattern.

Spontaneous Midsubstance Rupture of the Flexor Digitorum Profundus Tendon of the Long Finger

Closed flexor tendon injuries can often result from trauma that causes sudden forceful extension of an actively flexed digit. These closed tendon injuries commonly occur as avulsions in flexor zone I. Spontaneous midsubstance flexor tendon ruptures are rare, especially in the absence of an underlying pathology. Diagnosing such injuries accurately is challenging and critical. We present a case of a zone III spontaneous flexor tendon rupture of the long finger after forceful eccentric loading. Surgical exploration was performed, and the level of the rupture was identified during surgery. A side-to-side tendon repair technique was performed using a palmaris longus tendon graft. No underlying pathology to explain the rupture was found in this case. This report emphasizes the importance of considering spontaneous midsubstance ruptures, identifying the level of ruptures, and preoperative planning for such cases. It reviews the possible causes and treatment of spontaneous flexor tendon rupture.

Wide-Awake Approach for Flexor Digitorum Superficialis Tendon Transfer Followed by Early Active Mobilization

Background The standard clinical practice to treat closed ruptures of the flexor digitorum profundus (FDP) tendons includes free tendon grafting; however, it is not suitable when the muscle amplitude of the ruptured FDP is not sufficient. We report outcomes of six patients who underwent flexor digitorum superficialis (FDS) tendon transfer of the ring finger using the wide-awake approach to repair the closed rupture of the FDP tendon of the little finger in zone 3 or 4. Methods The patients were identified by reviewing our institutional billing records from January 2012 to October 2019 for the International Classification of Disease 10 code M66.3 that describes the diagnosis as "spontaneous rupture of flexor tendons." Results The patients comprised two men and four women with an average age of 72.2 years (standard deviation [SD], 8.4 years). All patients were hospitalized after surgery to undergo early active mobilization. The average total active motion at the final evaluation was 201.8° (range: 85-248°). According to Strickland's criteria, outcomes were excellent for two, good for three, and poor for one patient. No patients complained about the ring finger. Conclusion These results suggest that FDS tendon transfer is recommended when the muscle amplitude of the ruptured FDP is insufficient. We believe that the wide-awake approach and early active mobilization may contribute to satisfactory outcomes.

Fine tuning of the side-to-side tenorrhaphy: A biomechanical study assessing different side-to-side suture techniques in a porcine tendon model

Recent studies conclude that a new technique for tendon transfers, the side-to-side tenorrhaphy by Fridén (FR) provides higher biomechanical stability than the established standard first described by Pulvertaft (PT). The aim of this study was to optimize side-to-side tenorrhaphies. We compared PT and FR tenorrhaphies as well as a potential improvement, termed Woven-Fridén tenorrhaphy (WF), with regard to biomechanical stability. Our results demonstrate superior biomechanical stability and lower bulk of FR and, in particular, WF over PT tenorrhaphies. The WF and FR technnique therefore seem to be a notable alternative to the established standard tenorrhaphy as they display lower bulk and higher stability, permitting successful immediate active mobilization after surgery.

Transfer of distal peroneus longus tendon to tibialis anterior by retrograde fixation to treat spastic equinovarus foot in adults: Surgical Technique and Preliminary Results

We describe a retrograde transfer of the distal tendon of the peroneus longus (PL) onto the tibialis anterior (TA) tendon to treat spastic equinovarus foot (SEVF) in adults. The fact that the distal tendon insertions of the PL and TA are a mirror image makes them antagonists. The aim is to divert the distal tendon in front the inactive distal PL tendon, by fixing to the TA in the middle third of the lower leg. This transforms it into a dorsiflexor and reinforces its eversion ability. The suture level helps to avoid skin impingement when wearing shoes, and the complications inherent to transosseous fixation. In a preliminary case series of 10 patients, we found no complications at a mean follow-up of 4.7 years. The Foot Posture Index-6 improved by an average of 2.4 points. Four patients had regained active dorsiflexion. All patients reduced their use of orthotics. All patients improved according to Goal Attainment Scaling.

Biomechanical comparison of tenorrhaphy constructs for tendon reconstructions and transfers

With tendon transfers or reconstructions, the tenorrhaphy must be strong enough to withstand early mobilization in the immediate postoperative period to decrease adhesion formation and optimize functional outcomes. The purpose of this study was to compare the strength, bulk, and gliding resistance of four common tendon-to-tendon attachment constructs. A biomechanical study was performed utilizing 80 cadaveric tendons to compare four common tendon tenorrhaphy constructs: the end-weave (EW); Pulvertaft (PT); single-pass, side-to-side (SP-STS); and simple, side-to-side (STS) attachments. The primary outcome measures investigated included tenorrhaphy morphology, gliding resistance, tensile strength, and deformation at failure of the different constructs. A total of 40 tendon pairs, 10 per repair group, were constructed, biomechanically evaluated, and outcomes were compared. There were no significant differences in the cross-sectional area of the native tendon (p = 0.334) or repair site (p = 0.564) and no difference in the added bulk of the repair (p = 0.663) between the repair groups. Gliding resistance was not significantly different between the repair groups (p = 0.110). The SP-STS repair was significantly stronger (p < 0.001), stiffer (p < 0.001), and exhibited less displacement at peak load (p = 0.004), and greater force generation at 1 cm of displacement (p = 0.002) compared to the other constructs. The SP-STS is significantly stronger, without a significant difference in bulk and gliding resistance compared to the PT, EW, STS repairs. SP-STS can be utilized in tendon transfers and reconstructions to safely permit early active mobilization.

Transfer of the Posterior Tibial Tendon for Chronic Peroneal Nerve Palsy

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The common peroneal nerve (CPN) is one of the most frequently injured nerves of the lower extremity.

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One-third of patients who develop CPN palsy proceed to chronic impairment without signs of recovery.

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Ankle-foot orthoses can provide improvement with respect to gait dysfunction and are useful as a nonsurgical treatment option.

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Severe cases of CPN palsy demonstrating no signs of recovery may require operative intervention with tendon transfer.

Can Tho Transfer Technique: Extensor Hallucis Longus to Tibialis Anterior Tenodesis for Footdrop

BACKGROUND

Footdrop, or the inability to actively dorsiflex the foot, may result from numerous pathologic conditions, including poliomyelitis and cerebral palsy. Although the gait of patients with footdrop can be improved by performing an extensor hallucis longus (EHL) to tibialis anterior (TA) tendon transfer, the success rate of this procedure is relatively low.

METHODS

Seven paralytic patients with footdrop were surgically treated using a new buttonhole-type technique that involves passing a loop of the EHL through a TA split using umbilical tape and suturing at the four corners of the EHL attaching to the TA while the foot is dorsiflexed.

RESULTS

Eight years after surgery, all three patients who were available for follow-up displayed active dorsiflexion, improved mobility, and a palpable TA-EHL tenodesis, with no cockup deformity.

CONCLUSIONS

This new approach, which we term Can Tho transfer, improves the mechanical strength of TA-EHL tenodesis.

Partial Calcaneus Reconstruction using 'Opportunistic Grafts': A Case Report

Although replantation of an amputated extremity has been successfully performed, occasionally the surgeon is forced to amputate in the case of an unsalvageable open fracture. These appendages can theoretically act as an autologous 'bone and tissue bank' for patients if they have reconstructable contralateral injuries. We present a case of an athlete who sustained a Gustilo and Anderson IIIC injury on 1 leg resulting in a below knee amputation. Her other lower leg had a traumatic amputation of the heel pad, partial amputation of the calcaneus, and complete Achilles tendon loss. Tissues from this amputated appendage were utilised to restore the anatomy of the contralateral extremity. The distal tibia and the tibialis anterior from the amputated limb were used to reconstruct the missing posterior tuberosity of the calcaneus and the Achilles tendon respectively. The soft tissue deficiency of the heel pad was restored with an anterolateral thigh free flap. At 2-year follow-up, the patient is pain free and back to playing soccer. This case highlights the opportunistic use of amputated parts to reconstruct a calcaneus and Achilles tendon. A multidisciplinary approach with plastic surgeons is required. The main advantage of this 'Spare Part Surgery' philosophy is to provide autologous graft of a similar geometry and to avoid harvesting tissues from an additional donor site.

Biomechanical Comparison of Tendon Coaptation Methods With a Meshed Suture Construct

PURPOSE

Tendon-to-tendon attachment constructs for tendon reconstructions or transfers need to be secure in order to allow early mobilization after surgery. The purpose of this study was to biomechanically compare 2 common constructs secured with a novel mesh suture versus a nonabsorbable braided suture.

METHODS

We used 100 cadaveric tendons to create 5 different tendon coaptation constructs (a to e) (10 coaptations per group): (a) Pulvertaft weave with a braided suture (PTe); (b) mesh suture (PTm); (c) single-pass, side-to-side (SP-STS) coaptation with 30-mm overlap using a mesh suture (SP-STS-30m); (d) SP-STS 50-mm overlap with a mesh suture (SP-STS-50m); and (e) SP-STS with 30-mm tendon overlap using a braided suture (SP-STS-30e). The tensile strength, bulk, gliding resistance, and failure type were compared.

RESULTS

There was no difference between the various tendon constructs and the suture type in terms of coaptation bulk. All SP-STS constructs with mesh suture had higher peak gliding resistance than any of the PT constructs regardless of suture type. Compared with the PT constructs, the SP-STS constructs with mesh or braided suture had a higher peak load, peak load normalized to repair length, and stiffness. Within each tendon coaptation construct group, Pulvertaft or SP-STS, the suture type did not affect any of the investigated parameters.

CONCLUSIONS

The SP-STS constructs are significantly stronger and stiffer than the PT constructs. The SP-STS with mesh suture exhibited greater gliding resistance than the PT constructs and may result in greater gliding resistance through physiological tissue planes. However, the use of a mesh suture did not affect strength, bulk, gliding resistance, or failure type when compared within a construct group.

CLINICAL RELEVANCE

The use of SP-STS constructs for tendon coaptations produces a stronger and stiffer construct than the PT weave; however, the use of a mesh suture may not provide any benefit over a braided suture.

Biomechanical Study Comparing Pulvertaft, Double Side-to-Side, and Locking Side-to-Side Tendon Suture Techniques

PURPOSE

In this study, we present a single-sided locking side-to-side (STS) suture technique as a possible alternative for the Pulvertaft weave in tendon transfers. The aim of the study was to compare the biomechanical characteristics of the single-sided locking STS reconstruction with Pulvertaft and double-sided nonlocking STS reconstructions.

METHODS

Twenty-four human cadaveric extensor digitorum communis tendons and 24 flexor digitorum superficialis tendons were randomly assigned to 1 of 3 groups, resulting in a total of 8 flexor tendons and 8 extensor tendons per group: Pulvertaft, double-sided nonlocking STS, and single-sided locking STS reconstructions. Load to failure was measured with a tensile testing machine. Increase in cross-sectional area was used as a measure of bulkiness at the reconstruction site.

RESULTS

In extensor tendons, single-sided locking STS reconstructions showed a higher load to failure than Pulvertaft reconstructions, whereas no difference was found in load to failure between single-sided locking and double-sided nonlocking STS reconstructions. In flexor tendons, single-sided locking STS reconstructions showed a higher load to failure than Pulvertaft reconstructions. However, load to failure of single-sided locking STS reconstructions was less than double-sided nonlocking STS reconstructions. In both extensor and flexor tendons, the percent increase in cross-sectional area at the reconstruction site was higher in Pulvertaft reconstructions than single-sided locking STS reconstructions, whereas no difference was found between single-sided locking STS and double-sided nonlocking STS reconstructions.

CONCLUSIONS

Single-sided locking and double-sided nonlocking STS reconstructions are suitable alternatives to the Pulvertaft technique for tendon transfers owing to a higher strength and less bulkiness. Because load to failure of both STS reconstructions did not differ in extensor tendon transfers, the single-sided locking STS reconstruction seems especially suitable for extensor tendon transfers.

CLINICAL RELEVANCE

This study provides anatomical evidence that the single-sided locking STS reconstruction yields a higher strength and is less bulky than the Pulvertaft reconstruction in tendon transfers.

[Simplified active motion protocol following Extensor indicis to Extensor pollicis longus tendon transfer using a side-to-side suture]

BACKGROUND

Ruptures of the Extensor pollicis longus tendon are commonly treated by Extensor indicis transfer using Pulvertaft suture technique. Current literature does not yet give evidence for a preferable post-operative therapy protocol. A side-to-side suture technique is significantly stronger than the Pulvertaft repair technique and therefore allows an immediate active postoperative treatment. We present a new postoperative protocol, which is simple, fast and safe, and should make treatment easier for patients and therapists.

PATIENTS AND METHODS

We treated 10 patients with a transfer of the extensor indicis tendon between 07/2016 and 08/2017 according to the new active protocol. Patients were seen for follow-up at 2, 4 and 8 weeks. Thumb range of motion, pinch and grip strength as well as subjective parameters like pain and general satisfaction were measured.

RESULTS

All patients regained full function of their thumbs with retropulsion over the level of the palm at 4 weeks. Median pinch strength was 89 % and grip strength 74 % of the contralateral side at week 4. There was no secondary rupture of the reconstructed tendon over a one-year period. All patients were satisfied with the result of the operation and the protocol.

CONCLUSION

Our new active postoperative protocol for extensor indicis transfer using a side-to-side suture has proven to be safe and less strenuous for patients and therapists and has been established as standard treatment in our clinic.

Outcome of primary tendon grafts for open Zone 3 extensor tendon injuries

Open injuries of the extensor mechanism in Zone 3 (dorsum of the proximal interphalangeal joint) have poor outcomes. We retrospectively analysed the outcomes of treating 19 Zone 3 extensor tendon injuries in 17 patients. The treatment comprised wound excision and debridement, primary tendon graft to reconstruct the damaged/missing extensor tendon, skeletal fixation when required, local flaps to vascularize the zone of injury and immediate short arc motion therapy. Using the criteria defined by Geldmacher et al., the outcome was predicted to be poor in nine, satisfactory in seven and good in three cases. In this study the outcomes were excellent in 10, good in six and satisfactory in three cases. Mean range of motion was 75° (range 25°-115°) at the proximal interphalangeal joint. We conclude that using the protocol described there should no longer be the perception of a dismal outcome for these complex Zone 3 extensor tendon injuries.Level of evidence: IV.

Strength of side-to-side and step-cut repairs in tendon transfers: biomechanical testing of porcine flexor tendons

The aim of the study was to compare side-to-side with step-cut repairs to determine how much of the width it is possible to remove and still keep the repair strong enough to start active mobilization. Porcine flexor tendons were used to create side-to-side, one-third step-cut and half step-cut repairs. There were 15 repairs in each group. The tensile properties of the constructs were measured in a biomechanical testing machine. All repairs failed by the sutures splitting the tendon longitudinally. The maximum load and stiffness were highest in the side-to-side group. Our findings suggest that the half step-cut repair can withstand the forces exerted during active unrestricted movement of the digits in tendons of this size. The advantage of the step-cut repair is reduced bulkiness and less friction, which might compensate for the difference in strength.

The strengths of one-, two-, and three-weave Pulvertaft tendon repairs

We tested the tensile strength of the proximal juncture of tendon grafts with Pulvertaft tendon repairs in 18 cadaveric digital flexor tendons. These tendons were divided into three groups of six: single, two, or three weaves. Each of the interlacing weaves was secured with eight anchoring sutures. The specimens were loaded in a biomechanical tester until failure. The ultimate tensile strength did not show any significant differences across all three groups with statistical power of 0.77. The mean tendon elongation before repair failure showed significant difference at 10 mm (standard deviation (SD) 2), 16 mm (SD 3), and 15 mm (SD 3), respectively. All specimens failed by intra-tendinous pull-out of the weaves. We conclude that the two-weave Pulvertaft construct demonstrated comparable tensile strength to three weaves and tendon elongation was similar when two or three weaves were used.

Management of complex forearm defects: A multidisciplinary approach

Complex forearm defects with significant damage to, or loss of skin, tendon, muscle, bone and neurovascular structures represent a great challenge for surgeons. The management of such injuries, whether a result of trauma or tumor resection, is focused on preservation of the damaged limb and restoration of hand function. A multidisciplinary approach combining plastic and orthopedic surgical expertise in a coordinated team is proposed to address these challenging cases. The authors have laid emphasis on adequate debridement for wound bed preparation, bone stabilization and reconstruction for a stable bony framework, vascular repair for early revascularization, musculotendinous and nerve reconstruction as well as vascularized tissue coverage on a case-to-case basis to facilitate optimal functional recovery. They also maintain that besides expedient surgical treatment, early mobilization based on an individualized rehabilitation program as well as psychological and socio-professional supports are necessary means of achieving rapid and successful social integration.

Upper Extremity Tendon Transfers: A Brief Review of History, Common Applications, and Technical Tips

Background  Tendon transfer in the upper extremity represents a powerful tool in the armamentarium of a reconstructive surgeon in the setting of irreparable nerve injury or the anatomic loss of key portions of the muscle-tendon unit. The concept uses the redundancy/expendability of tendons by utilizing a nonessential tendon to restore the function of a lost or nonfunctional muscle-tendon unit of the upper extremity. This article does not aim to perform a comprehensive review of tendon transfers. Instead it is meant to familiarize the reader with salient historical features, common applications in the upper limb, and provide the reader with some technical tips, which may facilitate a successful tendon transfer.

Learning Objectives  (1) Familiarize the reader with some aspects of tendon transfer history. (2) Identify principles of tendon transfers. (3) Identify important preoperative considerations. (4) Understand the physiology of the muscle-tendon unit and the Blix curve. (5) Identify strategies for setting tension during a tendon transfer and rehabilitation strategies.

Design  This study was designed to review the relevant current literature and provide an expert opinion.

Conclusions  Tendon transfers have evolved from polio to tetraplegia to war and represent an extremely powerful technique to correct neurologic and musculotendinous deficits in a variety of patients affected by trauma, peripheral nerve palsies, cerebral palsy, stroke, and inflammatory arthritis. In the contemporary setting, these very same principles have also been very successfully applied to vascularized composite allotransplantation in the upper limb.

Upper-Extremity Reconstruction in Tetraplegia: A Critical Analysis Review

Management of tetraplegia should be individualized to a patient's particular deficiencies and functional goals. Surgical decision-making for upper-extremity reconstruction in patients with tetraplegia relies on a thorough physical examination to determine which nerves and muscles remain under volitional control with adequate strength for transfer. Peripheral nerve transfers, either in conjunction with or in place of traditional tendon transfers, enable providers to offer an expanded set of surgical options for patients with tetraplegia who are seeking upper-extremity reconstruction. All upper-extremity reconstructive efforts should be carefully considered with regard to their potential effects on the availability of future reconstructive efforts.

[Postoperative treatment and rehabilitation following flexor tendon injuries]

BACKGROUND

The ideal surgical and postoperative treatment for flexor tendon injuries, especially in zone 2, is still subject to continuous modifications and professional discussions.

OBJECTIVE

Presentation of established rehabilitation concepts, specific problems and new treatment approaches with practical recommendations for application.

MATERIAL AND METHODS

Comparison of commonly used treatment concepts by assessing surgical flexor tendon repair, splint choice and clinical application in patients. Discussion of new surgical approaches and standards and their influence on postoperative therapy after flexor tendon injuries.

RESULTS

The Washington regimen has retained its status as the standard in the current follow-up treatment of flexor tendon injuries. New suture materials and techniques enable early active rehabilitation of sutured flexor tendons with good clinical results, such as increased range of motion for interphalangeal joint extension and improved distal interphalangeal joint flexion with overall acceptable frequencies of suture rupture.

CONCLUSION

A stable tendon repair with smooth gliding is the foundation for treatment after flexor tendon injuries. After intraoperative active digital extension-flexion testing of the sutured tendon an early active rehabilitation approach should follow. New splint designs in combination with primary stable tendon suture techniques have the potential to improve the postoperative outcome, presupposing a reliable cooperation of the patient.

Rheumatoid Hand and Wrist Surgery: Soft Tissue Principles and Management of Digital Pathology

Since the advent of disease-modifying antirheumatic drugs for rheumatoid arthritis, orthopedic surgeons see fewer patients in the office who require hand surgery. However, a significant number of patients still seek surgical intervention to improve pain and function. These patients often present with isolated soft tissue pathologies, but even bone and joint pathology require meticulous soft tissue handling in this cohort. This review highlights the principles and techniques relevant to the management of soft tissue deformity in rheumatoid hand and wrist surgery, as exposure in training and practice continues to decrease.

Strength of Pulvertaft modifications: tensile testing of porcine flexor tendons

The aim of the study was to present two new modifications of the Pulvertaft weave, allowing a higher number of weaves without the need for a longer overlap. The mechanical properties were measured and compared with the traditional technique. Forty-five pairs of porcine flexor tendons were randomized to a Pulvertaft repair with three weaves, a Double Pulvertaft and Locking Pulvertaft repairs. In the last two repairs one of the tendons in each repair was split in two before weaving. A difference in the maximum stiffness was observed between the three groups (p = 0.024). All repairs failed by the sutures being sheared through the tendons splitting the tendon fibres longitudinally. The two modifications were both stronger than the Pulvertaft weave and provide an alternative when a strong connection is needed and a longer overlap is impossible.

Outcome of hand surgery in children with spasticity - a 9-year follow-up study

The aim of this study was to evaluate whether short-term positive effects on bimanual function after surgery of the paretic arm in cerebral palsy are maintained long term. Assisting Hand Assessment (AHA) and active range of motion was tested before surgery and at 7 month and 9-year follow-up (n=18). AHA improved significantly from 50 to 52 U at 7 months, but was not different from before surgery at the 9-year follow-up, 49 U. Surgery of wrist and elbow flexors significantly improved active extension. Improvement in wrist and elbow extension was maintained at the 9-year follow-up, but usefulness of the hand measured with AHA had returned to the same level as before surgery.

Reach out and grasp the opportunity: reconstructive hand surgery in tetraplegia

Reconstructive upper extremity surgeries in tetraplegia are technically challenging because of the many complicated real-time decisions that need to be made, e.g. extent of release of donor muscle-tendon complex, routing of donor muscles, tissue preparation and optimization, tensioning of muscle-tendon units, balancing joints and suturing tendon-to-tendon attachments. Nerve transfer surgeries can add functionality but also make the reconstruction planning more complex. In this overview, we present some of the fundamental muscle-tendon-joint mechanics studies that allow for single-stage surgical reconstruction of hand function as well as early postoperative activity-based training in patients with cervical spinal cord injuries. We foresee an increased need for studies addressing combined nerve and tendon transfer reconstructions in parallel with patient-perceived outcome investigations. These should be combined with implementation of assistive technology such as functional electrical stimulation for diagnostic, prognostic and training purposes.

Comparative Biomechanical Characteristics of Modified Side-to-Side Repair and Modified Pulvertaft Weaving Repair - In vitro Study

BACKGROUND

Strong surgical repair is the mechanical basis of early mobilization and prerequisite for biological healing following tendon grafting. Side to side and pulvertaft repairs were developed to meets these demands. However, these techniques have later been modified to improve the strength of repair but their characteristics have not been compared.

METHODS

We compared biomechanical strength of the modified side-to-side (SS) repair with the modified Pulvertaft (PT) repair technique in turkey tendons keeping overlap length, anchor points, type of suture, suture throw and amount of suture similar. Two investigators performed 34 repairs during one summer month to test the tensile strength of the repair using mechanical strength testing machine. Variables measured were maximum load, load to first failure, modulus, load at break, mode of failure, site of failure, tensile strain, tensile stress. The statistical comparison was carried by Levene's test and T test for means.

RESULTS

The mean maximum load for modified SS repair was 50.3 (SD 13.7) N and modified PT repair was 46.9 (SD 16.4) N. The tensile stress at maximum load for SS and modified PT repair was 4.7 (SD 4) MPa and 4.2 (SD 3) MPa respectively. The suture cut through was the commonest mode of failure.

CONCLUSIONS

We found no statistical difference between 2 repairs in load at which they started failing (p = 0.16), and maximum load repairs could withstand (p = 0.35). Our study uniquely compares two techniques under standard conditions, and contrary to existing evidence found no difference. However, in our opinion the number of anchor points may have a greater impact than number of weaves on the strength.

Suture constructs for rehabilitation using early active motion after tendon transfer surgery

The purpose of this study was to better define an ideal tendon transfer suture construct to allow for early active range of motion. A side-to-side tendon construct was used to test suture technique (cross stich vs. Krackow stitch), number of suture throws, and calibre of suture. A minimum load to failure of 100 N was used to comfortably allow early motion while minimizing rupture risk. All constructs tested, except the 4-0 Krackow construct, were strong enough to withstand 100 N of load. The choice of suture should be based on surgeon preference, patient compliance, and specific surgery, and 3-0 non-absorbable suture may be more suitable for tendon transfers from a yield force standpoint.

Management of Spinal Cord Injury-Induced Upper Extremity Spasticity

Spasticity affects more than 80% of patients with spinal cord injury. Neural mechanisms and musculotendinous alterations lead to typical upper extremity features including shoulder adduction/internal rotation, forearm pronation, and elbow, wrist, and finger flexion. Long-standing spasticity may lead to soft tissue and joint contractures and further impairment of upper extremity function. Surgical management involves tendon lengthening, release, and transfer, as well as selective neurotomy, in an effort to reduce spastic muscle hypertonicity, restore balance, prevent further contracture, and improve posture and function. This article summarizes surgical strategies to improve function of the upper extremity in patients with tetraplegia.

Technical Pearls of Tendon Transfers for Upper Extremity Spasticity

Tendon transfers are an important surgical option when treating patients with muscular imbalance due to upper extremity spasticity. A successful surgical outcome requires a thorough preoperative clinical evaluation, an understanding of tendon transfer biomechanics, appropriate donor and recipient muscle selection, technical execution, and postoperative rehabilitation. This article reviews the principles, biomechanics, and techniques for commonly performed tendon transfers in patients with upper extremity spasticity.

Peroneus Brevis Tenodesis: Side-to-Side or Weave?

Background:

Inversion ankle injuries are extremely common, sometimes causing injury to the peroneus brevis tendon. If more than 50% of the tendon is injured, it oftentimes requires tenodesis to the adjacent peroneus longus tendon. Both Pulvertaft (PT) and side-to-side (SS) techniques have been used for joining the 2 tendons. The purpose of this study was to compare the strength and stiffness of these 2 techniques.

Methods:

Five matched pairs of cadaver ankle specimens were randomized to receive either an SS or PT tenodesis of the peroneus brevis to longus tendons. Following the tenodesis, the specimens were tested for failure load, displacement, energy absorbed at failure, and peak load. Stiffness was also calculated. Paired t tests were performed to detect differences between the 2 conditions.

Results:

There were no statistically significant differences between the SS and PT tenodesis for any of the metrics measured. For stiffness, the techniques were very similar (SS = 10.14 [4.35], PT = 12.85 [1.72]).

Conclusion:

There is no difference in failure load, displacement, energy absorbed at failure, peak load or stiffness between the PT and SS techniques for peroneal tenodesis.

Level of Evidence:

Level V, cadaver study.

Biomechanical study comparing Pulvertaft suture to step-cut suture

Tendon grafts are a component of the therapeutic arsenal for managing chronic flexor tendons injuries in the hand, especially during two-stage Hunter reconstruction. The purpose of this anatomical study was to compare the strength of the Pulvertaft weave versus the step-cut suture used for flexor tendon reconstruction to determine their role in early active mobilization. We performed a biomechanical study with cadaver specimens. Thirty-four hands were randomized and the tendons from both hands were equally assigned to each group. A comparison of the Pulvertaft weave (group 1) versus the step-cut suture (group 2) using the flexor digitorum profundus from the fourth finger and the longus palmaris was carried out. The main variable was the failure load in both repair groups. We also evaluated the cross-sectional area (CSA) and the tensile strength of the repairs. Thirty hands were included in our study. There was no significant difference in the failure load between the two groups (116N for group 1 versus 103N for group 2, P=0.2). The CSA was significantly smaller in the step-cut group compared to Pulvertaft group (19.8mm² versus 35mm², P<0.01). The tensile strength was significantly higher in the step-cut group than in the Pulvertaft group (5.3N/mm² versus 3.4N/mm², P<0.01). Early active mobilization requires a minimum repair strength of 75N. In our study, the step-cut suture appears strong enough and thin enough to decrease the fibrosis, which would lead to better functional results. No other study of this type has been published. The specimens in which the repair strength was less than 75N all involved a thin, weak longus palmaris. Other biomechanical studies should be done to define the anatomical criteria required for use of the palmaris longus tendon. The step-cut suture seems to be strong enough and thin enough to provide sufficient proximal attachment during flexor tendon reconstruction to allow early active mobilization.

An ABC Technical Algorithm to Treat the Mangled Upper Extremity: Systematic Surgical Approach

Mangled upper extremity, as a result of trauma, is a life-altering event requiring a multidisciplinary approach for a successful outcome. All attempts are made to salvage the extremity and preserve function, which may require multiple complex procedures. This paper discusses the importance of a systematic reconstructive sequence and provides a review of commonly utilized techniques, supported with illustrative cases.

Minimally Invasive Palmaris Longus Abductorplasty for Severe Carpal Tunnel Syndrome

Camitz abductorplasty is the most commonly used tendon transfer in patients with severe carpal tunnel syndrome with significant muscle wasting and loss of opposition. This procedure requires a long incision in the palm to harvest a strip of palmar aponeurosis to lengthen the palmaris longus tendon, allowing it to reach the abductor pollicis brevis insertion. Several complications have been attributed to this extensive dissection in the palm. We describe a minimally invasive palmaris longus abductorplasty using a strip of free flexor carpi radialis tendon graft to achieve the necessary length. This can be done together with carpal tunnel release in patients with severe carpal tunnel syndrome.

Traumatic avulsion of the flexor digitorum profundus tendon. Jersey finger, a 29 cases report

Traumatic avulsion of flexor digitorum profundus (jersey finger) is an uncommon injury. Our study aimed to describe functional outcomes of jersey fingers after surgical treatment. From January 2004 to 2014, we performed surgery on 32 patients who had jersey finger. Twenty-six of these patients were male and 6 were female with a mean age of 37.2years (range 16-68). Of the 32 cases, 11 were sports injuries, 16 presented on the ring finger and 13 on the little finger. Using the Leddy and Packer and Smith classifications, 16 of the injuries were type I, 4 were type II, 5 were type III, 7 were type IV. The mean time between injury and surgery was 6.8days (range: 0-32). The surgical techniques used were anchor, pull-out, or an association of both these techniques. Prior to the patient discharge, functional outcomes were evaluated. Twenty-nine patients were evaluated in total and three patients were lost. Of the 29, the average time between surgery and discharge was 36.6months ranging from 4.5 to 118months. According to the Buck-Gramcko classification, six patients had an excellent result, six had a good result, seven had a satisfactory result and ten a poor result. The mean Quick DASH score immediately to prior discharge was 5.66 (range: 0-56.82). Twelve complications were reported on nine patients. No infections were reported. Rapid diagnosis and rapid surgical treatment led to restoration of full range motion.

Multicenter Survey of the Effects of Rehabilitation Practices on Pinch Force Strength After Tendon Transfer to Restore Pinch in Tetraplegia

OBJECTIVE

To identify key components of conventional therapy after brachioradialis (BR) to flexor pollicis longus (FPL) transfer, a common procedure to restore pinch strength, and evaluate whether any of the key components of therapy were associated with pinch strength outcomes.

DESIGN

Rehabilitation protocols were surveyed in 7 spinal cord injury (SCI) centers after BR to FPL tendon transfer. Key components of therapy, including duration of immobilization, participation, and date of initiating therapy activities (mobilization, strengthening, muscle reeducation, functional activities, and home exercise), were recorded by the patient's therapist. Pinch outcomes were recorded with identical equipment at 1-year follow-up.

SETTING

Seven SCI rehabilitation centers where the BR to FPL surgery is performed on a routine basis.

PARTICIPANTS

Thirty-eight arms from individuals with C5-7 level SCI injury who underwent BR to FPL transfer surgery (N=34).

INTERVENTION

Conventional therapy according to established protocol in each center.

MAIN OUTCOME MEASURES

The frequency of specific activities and their time of initiation (relative to surgery) were expressed as means and 95% confidence intervals. Outcome measures included pinch strength and the Canadian Occupational Performance Measure (COPM). Spearman rank-order correlations determined significant relations between pinch strength and components of therapy.

RESULTS

There was similarity in the key components of therapy and in the progression of activities. Early cast removal was associated with pinch force (Spearman ρ=-.40, P=.0269). Pinch force was associated with improved COPM performance (Spearman ρ=.48, P=.0048) and satisfaction (Spearman ρ=.45, P=.0083) scores.

CONCLUSIONS

Initiating therapy early after surgery is beneficial after BR to FPL surgery. Postoperative therapy protocols have the potential to significantly influence the outcome of tendon transfers after tetraplegia.

Biomechanical and Dimensional Measurements of the Pulvertaft Weave Versus the Cow-Hitch Technique

Background: In this study, biomechanical strength and bulkiness of the cow-hitch technique and Pulvertaft weave were compared. Our goal was to investigate whether the cow hitch can withstand equal strength in comparison with the Pulvertaft and to see if there is a difference in bulk, which could enhance gliding function and reduce friction and adhesion formation. Methods: Sheep tendons were used to perform 10 cow-hitch and 10 Pulvertaft repairs. Tensile strength was obtained with a cyclic loading tensile testing machine and tendon width and height measurements were obtained through digital analysis by photographs of the repairs. Results: The cow hitch showed significantly better ultimate strength and had less bulk. There was no statistical difference in displacement, defined as gain in total length of the tendon. Conclusions: The results in this study show that the cow hitch outperforms the Pulvertaft weave in both ultimate strength and bulk.

Side-to-Side Versus Pulvertaft Extensor Tenorrhaphy-A Biomechanical Study

PURPOSE

We hypothesized that a side-to-side (STS) tendon repair has biomechanical characteristics that match those of a Pulvertaft (PT) weave.

METHODS

Thirty extensor tendons were harvested (4 extensor digitorum communis and 1 extensor indicis proprius from 6 cadaver arms). Three hand surgery fellows with similar backgrounds of training under the same conditions and precise standardized technique performed the repairs (5 PT and 5 STS per surgeon). After the repairs, the tendons were passed through a graft-sizing guide to determine bulk and results were expressed as a repaired versus native diameter ratio. The specimens were then tested for ultimate strength and fatigue properties. Failure type and mechanical properties were recorded and compared with those of the native tendon.

RESULTS

The average peak force to failure was 93 ± 20 N for the STS and 62 ± 32 N for PT group. Relative strength ratio (repair strength compared with native tendon strength) was 37% ± 21% for the STS and 22% ± 11% for the PT group. In the STS group, all failures occurred as a result of tissue failure; however, in the PT, suture failures occurred in 3 tendons before tissue failure. The mean bulk ratio of the repaired site versus native proximal tendon was 37 ± 14% and 40% ± 22% more for the STS and PT groups, respectively. These values for native distal tendon were 28% ± 9.9% and 26% ±24 %, respectively for STS and PT repair. Furthermore, the bulk of the repaired site for the STS and PT groups was 4.2 ± 0.50 and 4.7 ± 1.2 mm, respectively.

CONCLUSIONS

Side-to-side repair technique showed superior biomechanical properties while demonstrating comparable repair bulk of the tendon coaptation compared with the Pulvertaft weave.

CLINICAL RELEVANCE

The results of this study may help guide a surgeon's choice of repair technique when addressing tendon injuries or tendon transfers.