Controlled active motion following primary flexor tendon repair: a prospective study over 9 years

Morphological Changes in Flexor Tendon Adhesion Following Early Exercise After Tendon Repair

Adhesion is a common complication following surgical repair of flexor tendons, resulting in the restriction of tendon gliding. We investigated the effect of early exercise on adhesion formation. To create an adhesion model, the proximal region of the second phalanx of the third toe in 4-month-old White Leghorn chickens was cut. The gliding side of the flexor digitorum profundus was hemiresected and the bony floor was crushed to enhance adhesion formation. The resected area was fixed in an extended position for 1, 2, or 3 weeks. Following 1, 2, or 3 weeks of active exercise, the chickens were sacrificed and morphological changes in the adhesions were assessed. In the 1- and 2-week fixed groups, 1, 2, or 3 weeks of active exercise resulted in mesotenon-like adhesion that was elastic and had no effect on tendon gliding. However, in the 3-week fixed group, a mature adhesion remained with limited change and tendon gliding was inhibited even after 3 weeks of active exercise. Thus, we concluded that adhesions become more elastic with early exercise within 2 weeks after tendon repair, but that adhesions following tendon repair tend not to show any further elastic changes when exercise is started 3 weeks after the repair.

Does methylene blue reduce adhesion during the healing process after tendon repair?

OBJECTIVES

This study aims to biomechanically and histopathologically investigate the effects of methylene blue (MB) on preventing postoperative adhesion in chickens undergoing full- thickness flexor tendon incision.

MATERIALS AND METHODS

This study was performed between June 2017 and June 2018 on Hubbard JA 57 type chickens (age, 6 months; weight, 2.2±0.3 kg). Sixty-four tendons were studied in 32 chickens, including 16 in the control group and 16 in the experimental group. The second and third finger flexor digitorum profundus tendons of the left foot of each chicken were repaired primarily after a full-thickness incision approximately 1 cm proximal to the distal adhesion area. In the control (n=32) and experimental groups (n=32), 0.25 mL of normal saline and 0.25 mL of 1% MB solutions were applied locally to the surgical site, respectively. The operated limb was immobilized using a circular cast. 16 chickens were randomly selected in each group and examined at the fourth week, and the remaining 16 chickens were examined at the sixth week. Thirty-two of these tendons were evaluated using the Tang histopathological adhesion classification system, and the other 32 were evaluated with a biomechanical pull system.

RESULTS

Adhesion was found to be less in the experimental group compared to the control group at the end of the fourth and sixth weeks both histopathologically and biomechanically. Furthermore, adhesion was significantly less in the experimental group at the end of the sixth week compared to the fourth week both histopathologically and biomechanically.

CONCLUSION

Histopathological and biomechanical results show that MB, which has anti-inflammatory, antiseptic, antimicrobial and antioxidant effects, reduces adhesion during the healing process after tendon repair. We think that local MB application, particularly in surgeries performed after this type of injury, will be beneficial on early rehabilitation and functional results.

[Primary treatment of flexor tendon injuries]

The treatment of flexor tendon injuries is still challenging, especially in the region of the narrow annular ligaments and tendon sheaths of the 3‑segment fingers and the thumb (zone 2). In the course of time, the primary suture of the flexor tendons has prevailed over traditional recommendations for a secondary tendon replacement after healing of the wound. Improvements regarding suture techniques and materials and, above all the follow-up treatment, have been crucial for better results and remarkable changes in flexor tendon surgery. The suture techniques are determined by the location of the injury but the experience and preferences of the surgeon are also important. Although no technique was found to be optimal, published research and clinical experiences provide important indications for the presumption of successful treatment. To achieve this an early functionally active protocol should be implemented. The tendon suture should enable this by having a high primary strength and therefore at least a 4-strand core suture technique with a ring suture should be given preference. Further important prerequisites for success are the undisturbed gliding of the repaired tendon in its "bed" paying special attention to the annular ligaments and preservation of the blood supply to the tendons.

Incidence of tenolysis and features of adhesions in the digital flexor tendons after multi-strand repair and early active motion

We report seven patients requiring tenolysis after primary or delayed primary flexor tendon repair and early active mobilization out of 148 fingers of 132 consecutive patients with Zone 1 or 2 injuries from 1993 to 2017. Three fingers had Zone 2A, two Zone 2B, and two Zone 2C injuries. Two fingers underwent tenolysis at Week 4 or 6 after repair because of suspected repair rupture. The other five fingers had tenolysis 12 weeks after repair. Adhesions were moderately dense between the flexor digitorum superficialis and profundus tendons or with the pulleys. According to the Strickland and Tang criteria, the outcomes were excellent in one finger, good in four, fair in one, and poor in one. Fingers requiring tenolysis after early active motion were 5% of the 148 fingers so treated. Indications for tenolysis were to achieve a full range of active motion in the patients rated good or improvement of range of active motion of the patients rated poor or fair. Not all of our patients with poor or fair outcomes wanted to have tenolysis. Level of evidence: IV.

Primary flexor tendons repair in zone 2: Current trends with GEMMSOR survey results

The repair of flexor tendon lesions in zone 2 remains a highly controversial subject in hand surgery. Currently, there is no consensus about the management of these lesions intra- and postoperatively, but the literature suggests that a solid suture will allow early active motion. We hypothesized that the management of flexor tendon injury in zone 2 varies widely. Two online surveys were conducted with surgeons and hand therapists. The questions captured the demographics of the surveyed population, surgical technique, common complications, postoperative management (duration of immobilization, type of splint, rehabilitation techniques and principles of self-rehabilitation). The responses were compared to current literature data. We collected 366 responses to the "surgery" survey and 206 responses to "rehabilitation" survey. Most surgeons performed suture repair with at least 4 strands (75.9%). Active rehabilitation protocols were used in 48.9% of cases. The "rehabilitation" survey underlined the lack of information provided to therapists by surgeons. Therapists used active protocols in 79.7% of cases. This study found a large variation in the management of flexor tendon injuries, which is not always consistent with current published recommendations. Ideally, the suture repair should be a 4-strand pattern with an epitendinous circumferential suture and a release of the pulley in the suture area. Mobilization and rehabilitation should be started on the 3rd day using an active protocol.

The impact of different peripheral suture techniques on the biomechanical stability in flexor tendon repair

PURPOSE

Flexor tendon repair consists of circumferential peripheral sutures in combination with core sutures to avoid fraying and reduces the exposure of suture material on tendon surface. The peripheral suture adds up to a tenfold increase of the biomechanical stability compared to the core suture alone. The purpose of our study was to determine the most favourable peripheral repair technique for tendon repair.

METHODS

Seventy-two porcine flexor tendons underwent standardized tenotomy and repair using one of the following six methods (n = 12): simple-running (SR), simple-locking (SL), Halsted-mattress (HM), lin-locking (LL), Lembert-mattress (LM), and Silfverskiöld cross-stich (SCS) suture technique. The SL- suture was placed 2 mm; the HM, LM, SC, and LL suture were placed 5 mm from the tendon gap. The SR suture was placed 1, 2, and 3 mm from tendon ends; no additional core suture was applied. For cyclic testing (1000 cycles), elongation was calculated; for load to failure construct stiffness, yield load and maximum load were determined.

RESULTS

The mean cyclic elongation for all tested suture techniques was less than 2 mm; there was no significant difference between the groups regarding elongation as well as yield load. The HM, LM, SCS, and LL suture techniques presented significantly higher maximum loads compared to the SR- and SL-sutures. The 3 mm SR showed significantly higher maximum loads compared to the 2 and 1 mm SR.

CONCLUSIONS

Beside the distance from tendon gap, the type of linkage of the suture material across and beneath the epitendineum is important for biomechanical stability. Simple-running suture is easy to use, even with a slight increase of the distance from tendon gap significantly increases biomechanical strength. For future repairs of flexor tendon injuries, 3 mm stitch length is highly recommended for simple peripheral suture, while the Halsted-mattress suture unites the most important qualities: biomechanically strong, most part of suture material placed epitendinous, and not too complicated to perform.

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.

Compliance, Adherence and Concordance: A Review of Engaging Patients in their Treatment

Problems of non-attendance in hand therapy clinics are frequently recorded and linked to poor outcomes in treatment. This paper reviews the therapy and medical literature on compliance, adherence and concordance, and explores ways of gaining the closer involvement and cooperation of patients in their treatment. It suggests that while client-centred approaches and education are important aspects of gaining users’ participation, patients need active encouragement and real opportunities to become involved in health care. Hand therapists need to explore ways in which to negotiate and tailor care to individual client needs.

Differential Splintage for Flexor Tendon Rehabilitation: An Experimental Study of its Effect on Finger Flexion Strength

We conducted laboratory tests to investigate the possibility of partly de-powering flexor digitorum profundus with a view of reducing flexion force during active flexor tendon rehabilitation.

We constructed a splint and applied tapes to the proximal segments of fingers to test the hypothesis that holding three fingers more extended than the other finger would reduce the flexion strength of the more flexed finger. The splint allowed the metacarpophalangeal joint of the more flexed finger to be held in three positions of increasing flexion (15°, 30°, and 45°) compared to the remaining three fingers. We have called this ‘differential splintage’.

Healthy volunteers were tested for maximum active flexion strength at the different flexion angles. ‘Differential splintage’ of up to 45° resulted in mean decreased flexion strength of 28% in the index finger and 35% to 38% in the middle, ring and little fingers.

The results suggest that “differential splintage” of a finger after flexor tendon repair may be useful in reducing tension across the repair during a program of active tendon rehabilitation and we feel that it has potential to reduce the incidence of repair rupture before healing is complete.

Effect of wrist and interphalangeal thumb movement on zone T2 flexor pollicis longus tendon tension in a human cadaver model

INTRODUCTION

Therapy after flexor pollicis longus (FPL) repair typically mimics finger flexor management, but this ignores anatomic and biomechanical features unique to the FPL.

PURPOSE OF THE STUDY

We measured FPL tendon tension in zone T2 to identify biomechanically appropriate exercises for mobilizing the FPL.

METHODS

Eight human cadaver hands were studied to identify motions that generated enough force to achieve FPL movement without exceeding hypothetical suture strength.

RESULTS

With the carpometacarpal and metacarpophalangeal joints blocked, appropriate forces were produced for both passive interphalangeal (IP) motion with 30° wrist extension and simulated active IP flexion from 0° to 35° with the wrist in the neutral position.

DISCUSSION

This work provides a biomechanical basis for safely and effectively mobilizing the zone T2 FPL tendon.

CONCLUSION

Our cadaver study suggests that it is safe and effective to perform early passive and active exercise to an isolated IP joint.

LEVEL OF EVIDENCE

NA.

Clinical outcomes of early active mobilization following flexor tendon repair using the six-strand technique: short- and long-term evaluations

We evaluated the factors influencing outcomes of flexor tendon repair in 112 fingers using a six-strand suture with the Yoshizu #1 technique and early postoperative active mobilization in 101 consecutive patients. A total of 32 fingers had injuries in Zone I, 78 in Zone II, and two in Zone III. The mean follow-up period was 6 months; 16 patients (19 fingers) participated in long-term follow-up of 2 to 16 years. The total active motion was 230° SD 29°; it correlated negatively with age. The total active motion was 231° SD 28° after repair of the lacerated flexor digitorum superficialis tendon, and was 205° SD 37° after excision of the flexor digitorum superficialis tendon ends (p = 0.0093). A total of 19 fingers showed no significant increases in total active motion more than 2 years after surgery. The rupture rate was 5.4% in our patients and related to surgeons' level of expertise. Five out of six ruptured tendons were repaired by inexperienced surgeons. Level of Evidence IV.

Thermographic and histological analysis of rabbit different tenorrhaphies techniques (4 and 6 strands) after early active mobilization

Introduction This research is based on the results of the surgeries of tenorraphy, which have been improved due to the association between strong and not voluminous sutures and physiotherapic protocols, which preconize the early active motion to the postoperative period. Objective To evaluate the healing process in vivo in different types of tenorraphies. Methods Thirty-six rabbits that underwent early active motion after tenorraphy. The sample was constituted of 3 groups of 12, in accordance with the 3 different types of suture (Brasil, Indiana and Tsai). Results On the 15th and 30th days after the surgery, thermographic and histological analyses revealed similar results that all groups showed similar behaviors in the same time of surgical repair, just differentiating between the periods. On the 30th day analysis were observed that collagen fibers being more exuberant thickening, thus being able to offer higher tensile strength to the tendon. Conclusion That suggests early active motion may be increased gradually to around the 30th day taking this as clinical relevance.

Primary flexor tendon repair in zones 1 and 2: early passive mobilization versus controlled active motion

PURPOSE

To compare early passive mobilization (EPM) with controlled active motion (CAM) after flexor tendon surgery in zones 1 and 2.

METHODS

We performed a retrospective analysis of collected data of all patients receiving primary flexor tendon repair in zones 1 and 2 from 2006 to 2011, during which time 228 patients were treated, and 191 patients with 231 injured digits were eligible for study. Exclusion criteria were replantation, finger revascularization, age younger than 16 years, rehabilitation by means other than EPM or CAM, and missing information regarding postoperative rehabilitation. This left 132 patients with 159 injured fingers for analysis. The primary endpoint was the comparison of total active motion (TAM) values 4 and 12 weeks after surgery between the EPM and the CAM protocols. The analysis of TAM measurements under the rehabilitation protocols was conducted using t-tests and further linear modeling. We defined rupture rate and the assessment of adhesion/infection as secondary endpoints.

RESULTS

There was a statistically significant difference between the TAM values of the EPM and the CAM protocols 4 weeks after surgery. At 12 weeks, however, there was no significant difference between the 2 protocols. Older age and injuries with finger fractures were associated with lower TAM values. Rupture rates were 5% (CAM) and 7% (EPM), which were not statistically different.

CONCLUSIONS

This study showed a favorable effect of CAM protocol on TAM 4 weeks after surgery. The percent rupture rate was slightly lower in the patients with CAM than in the patients with EPM regime. Further studies are required to confirm our results and to investigate whether faster recovery of TAM is associated with shorter time out of work.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

The role of animal models in tendon research

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

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

Flexor tendon repair rehabilitation protocols: a systematic review

PURPOSE

To systematically review various flexor tendon rehabilitation protocols and to contrast those using early passive versus early active range of motion.

METHODS

We searched PubMed and Cochrane Library databases to identify articles involving flexor tendon injury, repair, and rehabilitation protocols. All zones of injury were included. Articles were classified based on the protocol used during early rehabilitation. We analyzed clinical outcomes, focusing on incidence of tendon rupture and postoperative functional range of motion. We also analyzed the chronological incidence of published tendon rupture with respect to the protocol used.

RESULTS

We identified 170 articles, and 34 met our criteria, with evidence ranging from level I to level IV. Early passive motion, including both Duran and Kleinert type protocols, results included 57 ruptures (4%) and 149 fingers (9%) with decreased range of motion of 1598 tendon repairs. Early active motion results included 75 ruptures (5%) and 80 fingers (6%) with decreased range of motion of 1412 tendon repairs. Early passive range of motion protocols had a statistically significantly decreased risk for tendon rupture but an increased risk for postoperative decreased range of motion compared to early active motion protocols. When analyzing published articles chronologically, we found a statistically significant trend that overall (passive and active rehabilitation) rupture rates have decreased over time.

CONCLUSIONS

Analyzing all flexor tendon zones and literature of all levels of evidence, our data show a higher risk of complication involving decreased postoperative digit range of motion in the passive protocols and a higher risk of rupture in early active motion protocols. However, modern improvements in surgical technique, materials, and rehabilitation may now allow for early active motion rehabilitation that can provide better postoperative motion while maintaining low rupture rates.

The mechanical interaction between three geometric types of nylon core suture and a running epitenon suture in repair of porcine flexor tendons

The effect of core suture geometry on the mechanical interaction with the epitenon suture in terms of gap prevention, failure strength and mode of failure was investigated in a flexor tendon repair model. A total of 48 porcine flexor tendons were repaired using three techniques with distinct core suture geometry: single Kessler; double Kessler; and cruciate repair. Cyclic linear testing was carried out with and without a simple running epitenon suture. At failure load the epitenon suture reduced gapping by 87% in the double Kessler, 42% in the single Kessler and 15% in cruciate repairs. It increased the strengths of the repairs by 58%, 33% and 24%, respectively. Kessler repairs failed mainly by suture rupture, with and without epitenon suture, but cruciate repairs failed mainly by suture pull-out. The epitenon suture did not have a significant mechanical effect on the three repairs. Rather, its effect varied with the core suture geometry. The greatest effect occurred with double Kessler repairs.

Bundles of spider silk, braided into sutures, resist basic cyclic tests: potential use for flexor tendon repair

Repair success for injuries to the flexor tendon in the hand is often limited by the in vivo behaviour of the suture used for repair. Common problems associated with the choice of suture material include increased risk of infection, foreign body reactions, and inappropriate mechanical responses, particularly decreases in mechanical properties over time. Improved suture materials are therefore needed. As high-performance materials with excellent tensile strength, spider silk fibres are an extremely promising candidate for use in surgical sutures. However, the mechanical behaviour of sutures comprised of individual silk fibres braided together has not been thoroughly investigated. In the present study, we characterise the maximum tensile strength, stress, strain, elastic modulus, and fatigue response of silk sutures produced using different braiding methods to investigate the influence of braiding on the tensile properties of the sutures. The mechanical properties of conventional surgical sutures are also characterised to assess whether silk offers any advantages over conventional suture materials. The results demonstrate that braiding single spider silk fibres together produces strong sutures with excellent fatigue behaviour; the braided silk sutures exhibited tensile strengths comparable to those of conventional sutures and no loss of strength over 1000 fatigue cycles. In addition, the braiding technique had a significant influence on the tensile properties of the braided silk sutures. These results suggest that braided spider silk could be suitable for use as sutures in flexor tendon repair, providing similar tensile behaviour and improved fatigue properties compared with conventional suture materials.

The mechanics of flexor tendon adhesions

The mechanics of adhesions at a local tissue level have not been extensively studied. This study compared microstrains and macrostrains in adhesions of immobilized and mobilized partially lacerated flexor digitorum profundus tendons in a New Zealand White rabbit model. At 2 weeks, 50 digits were randomized to either gross tensile testing or micromechanical assessment, in which the movement of fluorescently labelled cell nuclei, acting as dynamic markers, was visualized using real-time confocal microscopy. The structural stiffness and load at failure of immobilized adhesions were 140% and 160% of that of mobilized adhesions, respectively, and both differences were statistically significant. Micromechanically, different patterns of loading and failure were observed. Mobilized adhesions exhibited over a three-fold higher local strain, which was less uniformly distributed. Confocal microscopy provided an accurate measure of local strain. For the first time, it has been possible to visualize, define, and quantify local adhesion tissue mechanics. Mobilization appears to favour the formation of sites expressing increased local strain responses or those predisposed to heterogeneity and localized failure.

Combining an external fixator and an artificial nerve-guide for the treatment of a complex digital injury

A complex digital injury, with tendon, nerve and bone losses, may pose the problem of which structure deserves the highest priority. Authors were able to treat tendon, nerve and bone lesions with the same level of priority thanks to the combined use of an external fixator and a nerve-guide.

A comparative analysis of the outcome of flexor tendon repair in the index and little fingers: does the little finger fare worse?

The clinical and hand therapy notes of 180 patients who had single digit flexor tendon repairs in zones I and II from January 2000 to December 2004 were reviewed. Data from 60 index and 108 little fingers at 5 weeks, 8 weeks and 12 weeks follow-up visits were included. In zone I injuries, there was a statistically significant difference in flexion contracture (worse in the little fingers ) at all follow-up points. Although the range of motion and percentage of patients in the excellent category of the Strickland and Glogovac criteria were greater in the index finger group than the little finger for zone I and II injuries, these differences were not statistically significant. The rupture rate was also higher in the little finger group.

Zone 2 flexor tendon injuries: Venturing into the no man's land

Flexor tendon injuries are seen commonly yet the management protocols are still widely debated. The advances in suture techniques, better understanding of the tendon morphology and its biomechanics have resulted in better outcomes. There has been a trend toward the active mobilization protocols with development of multistrand core suture techniques. Zone 2 injuries remain an enigma for the hand surgeons even today but the outcome results have definitely improved. Biomolecular modulation of tendon repair and tissue engineering are now the upcoming fields for future research. This review article focuses on the current concepts in the management of flexor tendon injuries in zone 2.

The longer pull-out suture as a transmission suture for early active motion of repaired flexor tendon at the proximal zone-2

OBJECTIVES

The purpose of the current study was to clinically evaluate the technique of longer pull-out suture as a transmission suture for early active motion after flexor tendon repair in the proximal zone-2.

METHOD

Eleven patients (eight adult male, two adult female and one child) with 19 proximal zone II flexor tendon lacerations were included. Mean age was 35 years. The patients were encouraged to perform active mobilization of the injured digits by themselves with full range of flexion from the first postoperative day. The pull-out suture was removed at the 8-10 weeks after the operation.

RESULTS

The mean follow-up was 39 months. The procedure was well tolerated by all of the patients. A patient of whom pull-out suture was traumatized and loosened at 6th week showed fair result. Two other patients with a history of blunt trauma were also found to have fair results. Overall 16 of the 19 digits were evaluated as excellent or good by the Strickland criteria.

CONCLUSION

The results of this method show that the longer pull-out suture technique as a transmission suture followed by early active mobilization is safe, has a low re-rupture rate and is easy to perform for proximal zone-2 flexor tendon injuries.

Systematic review of flexor tendon rehabilitation protocols in zone II of the hand

BACKGROUND

Restoration of function following flexor tendon repair in zone II represents a difficult clinical problem. Despite many publications on rehabilitation methods, there exists no consensus as to which method is superior. This study was undertaken to determine which flexor tendon rehabilitation protocol provides the best outcome after surgical repair in zone II.

METHODS

Electronic databases were searched for articles published between 1970 and 2009. The population included patients aged 5 years and older who sustained a flexor tendon laceration in zone II. The primary outcome was rupture rate. Secondary outcomes were range of motion and quality of life. The following protocols and their variations were considered: passive flexion and active extension protocols (Kleinert type protocols), controlled passive motion protocols (Duran type protocols), combination of the Kleinert and Duran protocols, and early active motion protocols.

RESULTS

Seventy-nine articles were identified. Fifteen studies met the inclusion criteria. The mean rate of rupture was lowest in the combined Kleinert and Duran protocols (2.3 percent) and highest in the Kleinert protocols (7.1 percent). No statistically significant differences were found. The combined Kleinert and Duran protocols and the early active motion protocols exhibited the highest proportion of digits with excellent or good results using the Strickland and Buck-Gramcko systems. One study included a quality-of-life assessment-meaningful comparison was not possible.

CONCLUSIONS

Both early active motion protocols and combined Kleinert and Duran protocols result in low rates of tendon rupture and acceptable range of motion following flexor tendon repair in zone II. Future studies should include quality-of-life measurements using validated scales.

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.

Hyaluronan modulates proliferation and migration of rabbit fibroblasts derived from flexor tendon epitenon and endotenon

PURPOSE

There is a growing body of evidence supporting the use of hyaluronan (HA) for treatment of injured tendons, although the mechanism of the healing effect has not yet been clarified. We therefore investigated the effects of HA on the proliferation and migration of tendon fibroblasts derived from rabbit flexor tendon epitenon and endotenon.

METHODS

From explanted rabbit intrasynovial flexor tendons (n = 5), we cultured tendon fibroblasts derived from the epitenon and endotenon. CD44 expression on the tendon fibroblasts was detected by flow cytometric analysis. Various concentrations of HA (0.1-5.0 mg/mL) were added to monolayer-cultured tendon fibroblasts. We evaluated cell proliferation by recording changes in cell number, and measured cell migration by wound-healing assay.

RESULTS

Flow cytometric analysis detected CD44 expression on the tendon fibroblasts. Treatment with HA at various concentrations notably and dose dependently inhibited cell proliferation and promoted cell migration.

CONCLUSIONS

Hyaluronan modulates the proliferation and migration of rabbit fibroblasts derived from the flexor tendon epitenon and endotenon.

Primary pulley enlargement in zone 2 by incision and repair with an extensor retinaculum graft

PURPOSE

This retrospective study documents the results of primary enlargement of tendon sheath pulleys by incision and extensor retinaculum graft repair during flexor tendon repairs in zone 2 in 9 fingers.

METHODS

The entire A2 or A4 pulley was enlarged by complete incision and repaired with an interposed extensor retinaculum graft at the time of primary flexor tendon repair in a total of 9 fingers in 7 patients, ages 15 to 54 years. The indication for primary pulley enlargement was failure of the tendon repair to glide smoothly and without snagging through the normally tight-fitting pulley system. In no case was more than one major pulley enlarged, and the entire A1 pulley was never enlarged. The zone 2 tendon repairs were done using a 2-strand modified Kessler 3-0 core suture and a 6-0 nylon running circumferential suture. The follow-up averaged 3.6 years. Interphalangeal total active motion and Strickland-Glogovac grade in patients with adequate follow-up of more than 6 months or obtaining full range of motion were obtained from a retrospective chart review.

RESULTS

Interphalangeal total active motion averaged 127 degrees and the scores according to the Strickland-Glogovac system were excellent for 3, good for 2, fair for 2, and poor for 2. There were no tendon ruptures. Two fingers in one patient required a tenolysis and a third finger had secondary skin scar lengthening. Two fingers had visible and palpable bowstringing when seen at long-term follow-up and there was an average flexion contracture of 21 degrees.

CONCLUSIONS

Primary pulley enlargement using a free graft in zone 2 tendon injuries may achieve the 3 goals of providing a good gliding environment, avoiding triggering, and minimizing bowstringing. These initial clinical outcomes are average for zone 2 tendon repair, but encouraging. Further research and refinement in surgical technique and rehabilitation method are needed to minimize flexion contractures.

The effects of human amniotic membrane and periosteal autograft on tendon healing: experimental study in rabbits

In this study, the effects of periosteal autograft and human amniotic membrane on tendon healing were compared. Forty-two New Zealand rabbits were divided into three groups. Flexor digitorum fibularis tendons were cut and repaired with a modified Kessler technique and circumferential sutures in all groups. Tendon repair alone was carried out in group 1, tendon repair and application of human amniotic membrane was done in group 2 and tendon repair and application of periosteal autograft was done in group 3. Biomechanical and histopathological examinations were done 2 and 6 weeks postoperatively. Biomechanical examination showed that group 3 was the strongest at weeks 2 and 6. Adhesion, inflammation and new bone formation showed no difference between groups at week 2. However, adhesion formation was found to be less in groups 2 and 3 than group 1 at week 6. The application of periosteal autograft might be useful in repair of tendon injuries.

Complications after flexor tendon injuries

Management of flexor tendon injuries is one of the most demanding tasks in hand surgery. Despite substantial improvements in surgical technique and postoperative rehabilitation protocols, functional outcomes may still be somewhat unreliable. In the present article, the authors present complications encountered after flexor tendon repair and provide their preferred methods of prevention and treatment.

Forces transmitted along human flexor tendons--the effect of extending the fingers against the resistance provided by rubber bands

We wished to test the hypothesis that postoperative extension of repaired flexor tendons against rubber bands will reduce the stress on the repairs, and therefore the risk of rupture. During 24 routine carpal tunnel decompression operations the force in flexor tendons was measured using a load cell. The patients flexed and extended their fingers with and without a rubber band providing resistance to extension. We found no statistically significant difference between the force measured in the tendon with or without the presence of rubber bands. To conclude, we have shown that if the application of rubber band dynamic splintage after flexor tendon repair has any advantage, it is not by reducing the forces transmitted along the tendon during resisted extension or by aiding flexion.

Auto-crosslinked hyaluronic acid gel accelerates healing of rabbit flexor tendons in vivo

This study's purpose was to assess the in vivo effect of auto-crosslinked hyaluronic acid (HA) gel, a natural HA derivative with increased viscosity and tissue residence time, on adhesions and healing of injured and surgically repaired rabbit digital flexor tendons. The second and third right deep digital flexor tendons from 48 rabbits (n = 96 tendons) were cut and repaired with a modified Kessler and running peripheral suture. Animals were randomized to two groups, receiving either HA gel or saline injected around both freshly repaired tendons. After 2, 3, 6, and 12 weeks, six rabbits in each group were euthanized. Tendon pull-out force and breaking strength were measured as a value for adhesion formation and tendon healing, respectively. A histological assessment of adhesions and healing was related to the mechanical results. A significantly faster increase in breaking strength was found in HA gel-treated compared to saline-treated tendons; this coincided with a significantly accelerated tissue repair response after injury. No significant difference in adhesion formation was found between the two groups at any time. Our results indicate a significant acceleration of in vivo healing of tendons treated with HA gel. Adhesion formation was unaffected. These results could have important clinical value in promoting rehabilitation after tendon injury.

Gliding resistance and strength of composite sutures in human flexor digitorum profundus tendon repair: an in vitro biomechanical study

PURPOSE

Although the strength of a tendon repair is clearly important, the friction of the repair is also a relevant consideration. The purpose of this study was to characterize the frictional coefficient, gliding resistance, and breaking strength of suture materials and a suture construct commonly used for flexor tendon repair.

METHODS

We measured the friction coefficients of 3-0 braided nylon enclosed in a smooth nylon outer shell (Supramid, S. Jackson, Alexandria, VA), 3-0 braided polyester coated with polybutilate (Ethibond, Ethicon, Somerville, NJ), and 3-0 braided polyester/monofilament polyethylene composite (FiberWire, Arthrex, Naples, FL) sutures. We also measured the gliding resistance, linear breaking strength, and resistance to gapping of zone 2 modified Pennington tendon repairs with the 2 lowest-friction sutures in 20 human cadaveric flexor digitorum profundus tendons.

RESULTS

The braided polyester/monofilament polyethylene composite had a significantly lower friction coefficient (0.054) than either the coated polyester (0.076) or nylon (0.130) sutures. The gliding resistances of the repaired tendons with braided/monofilament polyethylene composite suture and those of coated, braided polyester were similar. The strength of the 2 repairs (force to produce a 2 mm gap) and resistance to gap formation were also not significantly different.

CONCLUSIONS

Braided polyester composite is a low-friction suture material. However, when this suture was used for tendon repair with a locking suture technique, it did not show a significant effect on the gliding resistance and repair strength compared with the same repair using a coated polyester suture.

Biomechanical study of cross-locked cruciate versus Strickland flexor tendon repair

PURPOSE

Zone II flexor tendon repairs may create a bulging effect with resistance to tendon gliding. A biomechanical study was performed comparing the 4-strand cross-locked cruciate (CLC) to a 4-strand Strickland repair, both with and without an interlocking horizontal mattress (IHM) suture, in terms of strength characteristics and work of flexion.

METHODS

Sixteen fresh-frozen human fingers were placed in a custom jig. Flexor digitorum profundus tendons were sectioned at the A3 pulley level. Fingers were separated into 2 repair groups: 4-strand CLC and 4-strand Strickland core suture. Work of flexion was determined for each group, with and without an IHM circumferential suture. Final repair including IHM was tested for 2-mm gap failure and ultimate load to failure.

RESULTS

The CLC-IHM had a significantly smaller increase in work of flexion than the Strickland-IHM. For both suture types, the circumferential suture resulted in a statistically significant increase in work of flexion; however, peak entry force produced upon entry of the repair into the A2 pulley was reduced, although the decrease was not statistically significant for each group. The CLC-IHM had a significantly higher ultimate load to failure.

CONCLUSIONS

(1) The CLC-IHM suture method is stronger with less work of flexion than the Strickland-IHM method. (2) This new, combination repair method of CLC core suture with IHM circumferential suture is biomechanically superior to the commonly performed Strickland-IHM technique.

ICF components of corresponding outcome measures in flexor tendon rehabilitation - a systematic review

Background

The International Classification of Functioning, Disability and Health (ICF) delivers a holistic approach to health conditions. The objective of the present study is to provide an overview of flexor tendon rehabilitation outcome measures with respect to ICF components. Furthermore, it aims to investigate to which extent current assessments measure aspects of health according to these components primarily focussing on activity and participation.

Methods

A systematic literature review was conducted to identify all studies meeting the inclusion criteria. Studies were only included if they assessed more than body function and body structure and referred to the ICF components activity and participation. The outcome measures were analysed and their linkage to the ICF components were investigated to examine to which degree aspects of health outcome as defined by the ICF were considered.

Results

As anticipated, the application of outcome measures after flexor tendon repair is non conform. In many studies the emphasis still lies on physical impairment neglecting activity limitations and participation restrictions.

Aspects of health after flexor tendon repair could be assessed more adequately and cover patients' needs more sufficiently by choosing outcome measures which refer to all aspects of functioning.

Conclusion

The ICF can help to identify aspects of health which are not being considered. The ICF can help promote further development of adequate outcome measures including activity limitation and participation restrictions by targeting patient centred goals and respecting patients' needs.

Flexor tendon injuries of the hand treated with TenoFix: mid-term results

BACKGROUND

Recently, the Teno Fix device has been detailed in the literature. Conventional stranded cruciate repair requires splinting to protect the sutures from excessive loading, and then, active motion is strongly limited leading to a possible incomplete functional recovery.

MATERIALS AND METHODS

The authors report on their experience in treating 21 patients presenting primary flexor tendon injuries within the digital sheath in zone 2, in all fingers (including the thumb), at an average follow-up of 16 (range: 6-26) months.

RESULTS

There were, according to Strickland and Glogovac criteria: 12 excellent; 6 good; 3 fair.

CONCLUSIONS

This new device is practical clinically and can effect strong tendon repairs that withstand early active finger motion, but the best indication is to treat only selected cases of sharp flexor tendon lesions in zone 2. Using this technique it is possible to achieve a quick functional recovery and early return to work.

A novel biomimetic material for engineering postsurgical adhesion using the injured digital flexor tendon-synovial complex as an in vivo model

BACKGROUND

Many surgical procedures are complicated by adhesions. These restrictive fibrotic bands form between normally separate gliding tissue layers, potentially impairing function. The authors tested the adhesion-modifying effect of a novel fibronectin-derived biomimetic biomaterial in a tendon-synovial complex injury model.

METHODS

The deep flexor tendons of digits 2 and 4 in the right forepaw of 15 New Zealand White rabbits were subjected to 5-mm-long partial tenotomies. Animals were randomized to receive biomaterial tubes enveloping the tendon injuries or left untreated. Digits, amputated at 2 weeks, were randomized to mechanical pullout assessments of adhesion strength or to quantitative histologic cellularity and immunohistochemical proliferation (Ki67) assessments.

RESULTS

The mean peak pullout force required to break the adhesions was reduced from 7.70 N (n = 6) in untreated digits to 0.31 N (n = 7) in biomaterial-treated digits (p = 0.001). The mean structural stiffness of the adhesions was also significantly reduced (p = 0.001). Histologically, treated and untreated digits demonstrated an equal incidence of adhesions. The treated adhesions were 55 percent less cellular at their surface than the untreated injured controls (p = 0.003). Treated tendons were 8 percent more cellular (with equal numbers of proliferating cells) at their surface and significantly more cellular within their bulk than positive controls (p <or= 0.05).

CONCLUSION

This study suggests a significant reduction in the restrictive nature of postsurgical adhesions following treatment with the antiadhesive biomaterial without compromising tendon cellularity.

An analysis of factors associated with failure of tendon repair in the canine model

PURPOSE

The canine model is commonly used for flexor tendon repair research. The purpose of this study was to analyze the factors, including laceration mode (partial and complete), suture techniques, therapy methods, and weight-bearing status, associated with tendon repair rupture or gap formation in the canine model in vivo.

METHODS

We reviewed the factors associated with repair failure among 624 flexor tendon repairs in zone II from 242 dogs reported previously from our institution, including both partial and complete lacerations.

RESULTS

We found that weight-bearing due to failure of postoperative immobilization was the most important factor influencing tendon repair rupture or gap formation.

CONCLUSIONS

As has been noted clinically, in our canine model failure and gapping of a flexor tendon repair was primarily the result of uncontrolled loading. Rehabilitation strategies that reduce the risk of catastrophic loading of the repair are critical to reducing the experimental failure rate when using dogs for flexor tendon research. Similar strategies may also reduce such failures in humans.

Tendon Healing In Vitro: Adeno-Associated Virus-2 Effectively Transduces Intrasynovial Tenocytes with Persistent Expression of the Transgene, but Other Serotypes Do Not

BACKGROUND

Transfer of exogenous growth factor genes to injured tendons offers a promising method for strengthening tendon repairs. Adeno-associated virus vectors have advantages of being both nonpathogenic and nontoxic. The authors explored the efficiency of transduction of intrasynovial tenocytes with different serotypes of adeno-associated virus (AAV) and the persistency of its expression of a growth factor transgene.

METHODS

Tenocytes were obtained from cultures of rat intrasynovial tendons and distributed to 82 wells in eight culture plates and to 30 culture dishes. The tenocytes in the wells were treated with AAV1, AAV2, AAV3, AAV4, AAV5, AAV7, and AAV8 vectors containing the lacZ gene, and plasmid vectors (pCMVbeta-lacZ). The tenocytes were stained with in situ beta-galactosidase 5 days later. The basic fibroblast growth factor (bFGF) gene was cloned to the AAV2 vector to construct the AAV2-bFGF vector, which transduced tenocytes in culture dishes. Expression of the transgene was measured over 3 weeks and analyzed statistically.

RESULTS

AAV2 effectively delivered exogenous genes to proliferating intrasynovial tenocytes. In contrast, other tested adeno-associated viruses transduced tenocytes minimally or not at all. The efficiency of gene transfer by AAV2, indicated by the percentage of cells with positive beta-galactosidase staining, was significantly greater than that by a plasmid vector (p = 0.001). Expression of the bFGF gene in tenocytes transduced with the AAV2-bFGF was significantly higher than that in the control over the 3-week period (p < 0.01).

CONCLUSIONS

Gene transfer to tenocytes by AAV2 is more efficient than that by a plasmid vector. However, other adeno-associated virus serotypes cannot effectively transduce tenocytes. The bFGF gene can be delivered to intrasynovial tenocytes by the AAV2 vector effectively, and the gene transfer significantly increases expression of bFGF gene over 3 weeks.

Tendon injuries across the world: treatment

This article outlines current status of primary and secondary surgical treatment of flexor and extensor tendon injuries in the hand and rehabilitation regimens worldwide. Unsolved problems associated with tendon repairs in the hand are tendon adhesions, rupture of the repairs, finger stiffness, power of hand motion, and surgical skills. Future development may include improvement of tendon healing through biological approaches, repair techniques, and, in particular, establishment of adequate rehabilitation systems and training of surgeons in some regions of the world.

Functional outcome of the hand following flexor tendon repair at the 'no man's land'

PURPOSE

To evaluate the functional outcome of the hand following flexor tendon repair at 'no man's land' using 2 strands of a modified Kessler core suture and combined controlled motion rehabilitation protocol.

METHODS

Records of 31 zone-2 flexor tendon injuries in 21 digits of 16 patients between July 2000 and June 2005 were reviewed retrospectively. The injured tendons were repaired within 24 hours using 2 strands of a modified Kessler core suture, reinforced by a continuous circumferential epitendon suture. All patients completed a rehabilitation protocol that included active extension against a rubber band, passive flexion, and controlled passive extension and passive flexion exercises. Functional outcome of the fingers was assessed using the Buck-Gramcko II score. Hand grip strength, rehabilitation period, and rupture rate were also measured.

RESULTS

17 (81%) out of 21 digits in 15 out of 16 patients achieved an excellent-to-good functional grade. The remaining patient with concomitant injuries to 4 (19%) digits attained a poor functional grade, attributable to poor compliance with the rehabilitation protocol. The mean rehabilitation period was 130 days and the mean grip strength was 78% that of the uninjured side. Concomitant digital nerve injury did not adversely affect the final outcome. Only one (4.8%) patient experienced a rupture.

CONCLUSION

The surgical method and rehabilitation protocol used for zone-2 flexor tendon injury is safe and results in a reasonably good functional outcome.

Flexor tendon repair in zone II with 6-strand techniques and early active mobilization

PURPOSE

There are many biomechanic studies of 6-strand suture techniques for active mobilization, but few reports have described the clinical outcome in zone II flexor tendon lacerations. We discuss the clinical results of zone II flexor tendon repair using 2 of these techniques followed by controlled early active mobilization.

METHODS

Six-strand sutures using the number 1 technique by Yoshizu or a triple-looped suture technique were used to repair flexor tendons in 27 fingers from 21 consecutive patients. Fingers were mobilized by combining active extension and passive or active flexion in a protective splint for the first 3 weeks after surgery. The follow-up period averaged 13 months.

RESULTS

Based on the original Strickland criteria, the results were excellent in 17 fingers, good in 9, and fair in 1. The average flexion was 62 degrees for distal interphalangeal joints and 91 degrees for proximal interphalangeal joints. None of the repaired tendons ruptured.

CONCLUSIONS

The 6-strand flexor tendon suture technique followed by controlled active mobilization protected with a dorsal splint is safe, produces no ruptures, and achieves very good results in zone II flexor tendon laceration repair.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level II.

Complications after treatment of flexor tendon injuries

The goals of flexor tendon repair are to promote intrinsic tendon healing and minimize extrinsic scarring in order to optimize tendon gliding and range of motion. Despite advances in the materials and methods used in surgical repair and postoperative rehabilitation, complications following flexor tendon injuries continue to occur, even in patients treated by experienced surgeons and therapists. The most common complication is adhesion formation, which limits active range of motion. Other complications include joint contracture, tendon rupture, triggering, and pulley failure with tendon bowstringing. Less common problems include quadriga, swan-neck deformity, and lumbrical plus deformity. Meticulous surgical technique and early postoperative tendon mobilization in a well-supervised therapy program can minimize the frequency and severity of these complications. Prompt recognition of problems and treatment with hand therapy, splinting, and/or surgery may help minimize recovery time and improve function. In the future, the use of novel biologic modulators of healing may nearly eliminate complications associated with flexor tendon injuries.

Investigation of resistance of digital subcutaneous edema to gliding of the flexor tendon: an in vitro study

PURPOSE

Although edema generally is considered to contribute to resistance to tendon mobilization and is a cause of tendon overload during postoperative motion exercise, it is unclear exactly how edema of the peritendinous tissues affects tendon mobilization. We assessed the effects of simulated subcutaneous edema on the gliding resistance of the flexor tendon in an in vitro model using chicken toes.

METHODS

Thirty long toes of white Leghorn chickens were used. Twenty-two toes were divided into 2 groups and another 8 toes were used to determine the preconditions needed. In group 1 we produced 3 levels of edema severity in the subcutaneous tissue over a 1-cm segment by means of saline injection. In group 2 we created moderate tissue edema over 1-cm, 2-cm, or 3-cm segments of the toes. The work required to move the flexor digitorum profundus tendon over a fixed excursion and ultimate force were recorded with a testing machine after each run of flexion.

RESULTS

Work and ultimate force increased significantly in the toes with simulated tissue edema in proportion to the severity and area of the edema. Even the least severe edema increased the work and force; a further increase to moderate edema tripled the energy needed to flex the toes. Increases in edema from 1-cm to a 2-cm and then to a 3-cm toe segment increased the work and force for each increment of extension.

CONCLUSIONS

Simulated edema significantly increases energy and force required to move the tendons. The increase in resistance was proportionate to the severity and area of the edema. These results suggest that postoperative edema may increase significantly the resistance to tendon motion and that limiting both the severity and size of edema likely will reduce the resistance.

Zone I flexor tendon rehabilitation with limited extension and active flexion

This article describes an immediate active motion protocol for primary repair of zone I flexor tendons treated with tendon to tendon, or tendon to bone repair, and reviews clinical results. A rehabilitation protocol is proposed that will limit excursion of the zone I repair by blocking full distal interphalangeal (DIP) extension and by applying controlled active tension to both the unrepaired flexor digitorum superficialis (FDS) and the repaired flexor digitorum profundus (FDP). The rehabilitation technique utilized a dorsal protective splint with a relaxed position of immobilization with 30 degrees of wrist flexion, 40 degrees of metacarpophalangeal (MP) joint flexion, and a neutral position for the proximal interphalangeal (PIP) joints without dynamic traction. In addition, within the confines of the dorsal splint, the involved DIP joint was splinted at 40-45 degrees to prevent DIP joint extension during the early wound healing phases. Relaxed composite flexion was used to apply active tension to both the uninjured FDS, and the repaired FDP. This technique applies excursion of approximately 3 mm to the zone I tendon in a limited arc (45-75 degrees). The modified position of active flexion applies low loads of force (< 500 g), even with drag considered. This technique is supported by previous mathematical studies of excursion and internal tendon force, and clinical experience. Forty nine cases treated over a 10-year period were reviewed, and eight were excluded for incomplete follow-up. The use of this protocol for 41 zone I flexor digitorum profundus repairs by 12 different surgeons using varied surgical techniques was evaluated. None of the tendon to tendon repairs used more than two suture strands for the core repairs. Mean total active range of motion was 142 degrees (PIP 95 degrees plus DIP 47 degrees), or 81% of normal. Three tendons ruptured in non-protocol-related incidents and were excluded from the study. Results from this clinical study support the use of limited DIP extension combined with active tension with conventional repair in zone I.

The evolution of early mobilization of the repaired flexor tendon

The most important difference between the various approaches to postoperative digital flexor tendon rehabilitation is how the repaired tendon is treated during the first three to six weeks, in the earliest stages of healing. Early mobilization is the most commonly reported method of managing the healing flexor tendon. There are many different protocols and abundant research to support published approaches to tendon management. With so many choices, today's hand therapist must understand not only what those choices are, but also why and when to use them. There is no one correct way to manage a repaired flexor tendon; the specialist who does not understand how current techniques evolved is ill-equipped to design the appropriate treatment for a given patient. This article presents an overview of management options and how they have been developed over time, with special attention to changes in splint and exercise design in the crucial first few weeks after repair.

Clinical outcomes associated with flexor tendon repair

Review of the outcomes of clinical flexor tendon repairs reported over the past 15 years showed advances in the outcomes with excellent or good functional return in more than three fourths of primary tendon repairs following a variety of postoperative passive/active mobilization treatments. Strickland and Glogovac criteria are the most commonly adopted methods to assess function. Repair ruptures (4%-10% for zone II finger flexors and 3%-17% for the FPL tendon), adhesion formations, and stiffness of finger joints remain frustrating problems in flexor tendon repairs and rehabilitation. Four approaches are suggested to improve outcomes of the repairs and to solve these difficult problems,which include stronger surgical repairs, appropriate pulleys or sheath management, optimization of rehabilitation regimens, and modern biologic approaches.

Device for zone-II flexor tendon repair. A multicenter, randomized, blinded, clinical trial

BACKGROUND

The stainless-steel Teno Fix tendon-repair device has improved biomechanical characteristics compared with those of suture repair, and it was well tolerated in a canine model. The purpose of this study was to compare the Teno Fix with suture repair in a clinical setting.

METHODS

Sixty-seven patients with isolated zone-II flexor tendon injury were randomized to be treated with a Teno Fix or a four-stranded cruciate suture repair. There were eighty-five injured digits: thirty-four were treated with the Teno Fix, and fifty-one served as controls. A modified Kleinert rehabilitation technique was employed, with active flexion starting at four weeks postoperatively. Patients were followed for six months by blinded observers who determined the range of motion, Disabilities of the Arm, Shoulder and Hand (DASH) score, pinch and grip strength, and pain score on a verbal scale and assessed swelling and neurologic recovery. Adverse outcomes, including device migration and rupture, were monitored at frequent intervals.

RESULTS

Nine of the fifty-one suture repairs ruptured, whereas none of the Teno Fix repairs ruptured (p < 0.01). Five of the nine ruptures were caused by resistive motion against medical advice. There were no differences between the two groups in terms of range of motion, DASH score, pinch and grip strength, pain, swelling, or neurologic recovery. The Teno Fix group had slightly slower resolution of pain and swelling compared with the control group. Of the patients who were available for follow-up at six months, sixteen of the twenty-four treated with a Teno Fix repair and nineteen of the twenty-seven treated with a control repair had a good or excellent result. One Teno Fix device migrated and extruded secondary to a wound infection. Of all eighty-five digits that were operated on, four were thought to have tendons of inadequate size to accommodate the device and nine were deemed to have inadequate exposure to allow placement of the anchors.

CONCLUSIONS

The Teno Fix is safe and effective for flexor tendon repair if the tendon size and exposure are sufficient. Tendon repairs with the Teno Fix have lower rupture rates and similar functional outcomes when compared with conventional repair, particularly in patients who are noncompliant with the rehabilitation protocol.

The biomechanical analysis of a tendon fixation device for flexor tendon repair

PURPOSE

Stainless steel suture is high in tensile strength but is not widely used in flexor tendon repair because of difficulty with handling and knot tying. The purpose of this study was to examine the biomechanical characteristics of the single-strand multifilament stainless steel Teno Fix device (Ortheon Medical, Winter Park, FL) designed for zone II flexor digitorum profundus (FDP) tendon repair.

METHODS

Sixty cadaveric flexor tendons were transected and randomized to receive a Teno Fix or 4-stranded (3-0 or 4-0 braided polyester) suture repair; all repairs were tested with and without a 5-0 monofilament polypropylene circumferential epitendinous suture. By using a material testing system all tendons were tested to failure in tension using a linear model with a loading rate of 1 mm/s. Stiffness, force, and energy at both 2-mm gap and peak force were calculated from the resulting force-displacement curves.

RESULTS

The 2-mm gapping force was significantly greater for the Teno Fix and the 3-0 repairs than for the 4-0 repairs. The energy absorbed up to 2-mm gap was significantly greater for the Teno Fix, however, than for all suture repairs both with and without a circumferential suture. There was no statistically significant difference in peak force or energy absorbed at peak force between the Teno Fix and suture repairs; the average gap at peak force for all repairs was 5.2 mm. The addition of a circumferential suture increased the 2-mm gapping and peak forces of the Teno Fix repair to 54.5 N and 66.7 N, respectively.

CONCLUSIONS

Increased strength and energy absorbed at 2-mm gap and ease of installation makes the Teno Fix a promising repair method.

Pyramid of progressive force exercises to the injured flexor tendon

Postoperative rehabilitation for patients who have sustained a laceration to their flexor tendon apparatus is an important factor in maximizing functional outcome. Quality rehabilitation is characterized by the development of a tailored exercise regimen. There is currently no model available to tailor an exercise regimen for a person with an atypical physiologic response pattern. If rehabilitation protocols were classified according to the criteria of forces applied across a tendon juncture and/or excursion, and a clinical method were available to assist in the identification of optimal tendon loading and/or excursion application, then those individuals with atypical response patterns could be treated more efficiently and effectively. The author conducted a literature review and case study. A model for systematic application of progressive loading exercises to the intrasynovial flexor tendon injury and repair is conceptually developed. The model consists of a pyramidal series of eight specific rehabilitation exercises in the following sequence: passive protected extension, place and hold, active composite fist, hook and straight fist, isolated joint motion, resistive composite fist, resistive hook and straight fist, and resistive isolated joint motion. Concepts are developed to implement a three-point clinical adhesion-grading system. Clinical application of the system is highlighted. An excellent outcome was considered 112% total active motion. A model for systematic application of progressive loading exercises has been conceptually developed in concert with a method for determination of optimal tendon loading. Further substantiation is necessary to validate the proposed theory.