Relative motion flexion following zone I-III flexor tendon repair: Concepts,evidence and practice.

Study DesignNarrative review and case series.IntroductionThe relative motion approach has been applied to rehabilitation following flexor tendon repair. Positioning the affected finger(s) in relatively more metacarpophalangeal joint flexion is hypothesized to reduce the tension through the repaired flexor digitorum profundus by the quadriga effect. It is also hypothesized that altered patterns of co-contraction and co-inhibition may further reduce flexor digitorum profundus tension, and confer protection to flexor digitorum superficialis.MethodsWe reviewed the existing literature to explore the rationale for using relative motion flexion orthoses as an early active mobilization strategy for patients after zone I-III flexor tendon repairs. We used this approach within our own clinic for the rehabilitation of a series of patients presenting with zone I-II flexor tendon repair. We collected routine clinical and patient reported outcome data.ResultsWe report published outcomes of the clinical use of relative motion flexion orthoses with early active motion, implemented as the primary rehabilitation approach after zone I-III flexor digitorum repairs. We also report novel outcome data from 18 patients.DiscussionWe discuss our own experience of using relative motion flexion as a rehabilitation strategy following flexor tendon repair. We explore orthosis fabrication, rehabilitation exercises and functional hand use.ConclusionsThere is currently limited evidence informing use of relative motion flexion orthoses following flexor tendon repair. We highlight key areas for future research and describe a current pragmatic randomized controlled trial.     

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 degrees , 30 degrees , and 45 degrees ) 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 degrees 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.     

Repair of flexor carpi radialis tendon laceration at the wrist in a professional ice hockey player

The flexor carpi radialis is a wrist flexor and radial deviator with half the relative strength of flexor carpi ulnaris. In the majority of patients, the flexor carpi radialis tendon is expendable and is routinely used for various reconstructive procedures about the hand and wrist. Isolated flexor carpi radialis lacerations at the wrist are rare. Flexor carpi radialis tendon ruptures, which have been reported in association with distal radius fractures, longstanding osteoarthritis, and percutaneous treatment of scaphoid fractures, are usually treated non-operatively. We report a case of a traumatic laceration of the flexor carpi radialis tendon at the wrist in a professional ice hockey player. Surgical repair and rehabilitation using established principles for intrasynovial flexor tendon repair allowed return to sport at the professional level in 2 months.Tension-free core suture repair was performed with a modified-Kessler, 4-strand repair using a double-stranded 4-0 Supramid suture. A running epitendinous suture was then placed around the circumference of the tendon with 6-0 Prolene. Immobilization of the wrist in 20° of flexion was maintained for 2 weeks. Full active and passive digital motion was allowed immediately postoperatively and continued throughout the rehabilitation. Therapy was initiated at 2 weeks postoperatively with full passive wrist flexion and passive wrist extension to a dorsal block of 20°. At 4 weeks postoperatively, a dorsal splint was fabricated to keep the wrist in neutral. At this time, active extension to a dorsal block of zero and full passive flexion was allowed. Active wrist flexion without resistance was begun at 6 weeks, and full strengthening was allowed at 8 weeks postoperatively. The patient returned to sport at the professional level shortly thereafter. At latest follow-up, the patient has been able to fully participate in professional ice hockey without pain or functional limitation.     

Establishment of an in vivo turkey model for the study of flexor tendon repair

Flexor tendon injuries are common and pose a clinical challenge for functional restoration. The purpose of our study was to assess the adequacy of the turkey as a large animal model for flexor tendon injuries in vivo. Twenty‐four male turkeys underwent surgical flexor tendon cut and repair. Turkeys were allocated to five groups postoperatively: (1) foot casted in extension and sacrificed after 3 weeks; (2) foot casted in extension and sacrificed after 6 weeks; (3) foot casted in flexion and sacrificed after 3 weeks; (4) foot casted in flexion and sacrificed after 6 weeks; and (5) foot casted in flexion for 6 weeks and then free roaming allowed for an additional 3 weeks before sacrifice. After sacrifice, digits were collected and analyzed for adhesion formation, healing at the macrolevel and histologically, and biomechanical properties—including friction, work of flexion, stiffness, and strength of repair. All turkeys survived anesthesia and surgery. Tendon rupture occurred in all extension casts and in 11% of those casted in flexion. Friction and work of flexion were significantly higher in the repaired digit than the control digit. There was a correlation between duration of immobilization and repair strength. Histologically, the tendon healed with tenocytes migrating into the gap and producing collagen fibers. We have, for the first time, studied flexor tendon injury and repair using turkeys in terms of anesthesia, surgical procedures, postoperative care, and animal husbandry. The findings regarding functional and histological results from this novel avian model were comparable to the most commonly used mammal model. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2497–2505, 2018.

     

Intra-tendinous gout in a repaired flexor digitorum profundus

A patient presented with decreased flexion and triggering following a zone IIc flexor digitorum profundus repair 7 years previously. Chalky-white deposits, confirmed histologically as gout, were present at the repair site.     

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.     

In vivo flexor tendon forces increase with finger and wrist flexion during active finger flexion and extension.

The effects of different hand motions and positions used during early protected motion rehabilitation on tendon forces are not well understood. The goal of this study was to determine in vivo forces in human flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons of the index finger during active unresisted finger flexion and extension. During open carpal tunnel surgery (n = 12), flexor tendon forces were acquired with buckle force transducers, and finger positions were recorded on video while subjects actively flexed and extended the fingers at two different wrist angles. Mean in vivo FDP tendon forces varied between 1.3N +/- 0.9 N and 4.0 N +/- 2.9 N while mean FDS tendon forces ranged from 1.3N +/- 0.5 N to 8.5 N +/- 10.7 N. FDP force increased with active finger flexion at both wrist angles of 0 degrees or 30 degrees flexion. FDS force increased with finger flexion when the wrist was in 30 degrees flexion, but was unchanged when the wrist was in 0 degrees of flexion. Tendon forces were similar regardless of whether the fingers were moving in the flexion or extension direction. Active finger flexion and extension with the wrist at 0 degrees and 30 degrees flexion may be used during early rehabilitation protocols with limited risk of repair rupture. This risk can be further decreased for a FDS tendon repair by reducing wrist flexion angle.     

Early dynamic splinting for extensor tendon injuries

Extensor tendon injuries are traditionally splinted with no motion for 3 to 4 weeks after repair. This may result in limitation of flexion because of extensor tenodesis at the site of repair. To prevent this, we used a dynamic splinting program opposite to the one that is used for flexor tendon repair, with an outrigger splint holding the fingers in extension and allowing full active flexion. Fifty-two patients who had extensor tendon repairs in the area from the wrist to the middle of the proximal phalanx were treated. Motion was begun 2 to 5 days after repair and was continued for approximately 5 weeks. No tendon ruptures occurred, and all patients recovered full flexion.     

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.     

Flexor tendon nutrition

The concepts regarding nutrient pathways to flexor tendons within the digital sheath are reviewed. Historically, both diffusion and perfusion have been considered significant pathways to the flexor tendon. Theories of tendon healing and adhesion formation, as well as techniques employed by the surgeon in the repair of tendons, are based on these concepts.     

Optimizing independent finger flexion with zone V flexor repairs using the Massachusetts General Hospital flexor tenorrhaphy and early protected active motion

PURPOSE: Independent FDS action has been cited to be problematic with repair of multiple tendons in zone V owing to adhesion formation between the flexor digitorum superficialis (FDS) and the flexor digitorum profundus (FDP) tendons. Of the several described flexor repair techniques the ideal tendon repair should be strong enough to allow for early active motion to minimize adhesion formation and maximize tendon healing. Biomechanical studies have proven the Massachusetts General Hospital (MGH) repair to be strong enough to allow for early active motion. The purpose of this study was to examine the use of the MGH technique for zone V flexor tendon injuries to allow for early protected active motion to achieve independent finger flexion through better differential gliding of the tendons. METHODS: We performed a retrospective review 168 zone V finger flexor tendon repairs for 29 patients performed consecutively over 4 years when early active motion was not contraindicated. The same early protected active motion protocol was used for all of these patients. We reviewed total active motion, independent flexion, rupture, and need for tenolysis. These injuries involved 103 FDS and 65 FDP tendons to 103 fingers. The median follow-up period was 24 weeks. Of these 29 patients 19 were men and 10 were women. The average patient age was 28 years. RESULTS: The total active motion for these zone V repairs was 236 degrees +/- 5 degrees Overall 97 of 103 digits attained good to excellent function and 88 of 103 developed some differential glide. One of these patients required a tenolysis. Three repairs ruptured in 1 patient owing to suture breakage that was associated with noncompliance with the dorsal extension block splint. CONCLUSIONS: Our retrospective review of 168 consecutive flexor tendon repairs showed that the MGH technique allowed for early protected active motion, which provided good to excellent functional outcomes with 88 of 103 developing independent finger flexion at an acceptably low complication risk.     

The Effect of Pulley Reconstruction on Maximum Flexion,Bowstringing, and Gliding Coefficient in the Setting of Zone II Repair of FDS and FDP: a Cadaveric Investigation

Purpose

The purpose of this experiment was to determine the effect of A2 pulley reconstruction on gliding coefficient (GC), bowstringing, and proximal interphalangeal (PIP) joint maximum flexion angle after zone II repair of flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) lacerations.

Methods

Fresh frozen cadaver forearms were mounted, and the wrist and MCP joints fixed. FDS and FDP tendons were dissected free, and sequential loads were applied while digital images were captured. The dissected digit with intact native A2 pulley, FDS, and FDP tendons was used as the control (group 1). Zone II lacerations followed by four-stranded repair of FDP plus epitendinous suture and repair of FDS were then performed, and the data recorded (group 2). A2 pulley excision and reconstruction with a loop of palmaris longus autograft was then completed and the specimens sequentially loaded and photographed (group 3). Using the digital images, GC, bowstringing, and maximum flexion angle were calculated.

Results

No difference in maximum flexion angle was observed across the three testing conditions. Zone II laceration and subsequent FDS and FDP tendon repair significantly increased the GC for group 2 specimens; however, pulley reconstruction alleviated some of this increase for group 3. Bowstringing was significantly greater after pulley reconstruction, with a mean increase of 1.9 mm at maximum flexion for group 3 specimens relative to group 1 controls.

Discussion

Strong flexor tendon repairs are needed to prevent gap formation and subsequent triggering; however, the increased bulk from these large repairs can itself produce deleterious triggering, as well as tendon abrasion. Pulley reconstruction, in the setting FDP and FDS repair (group 3), significantly reduced the GC relative to tendon repair alone (group 2). While bowstringing was significantly greater after pulley reconstruction (group 3), it averaged only 1.9 mm over group 1 specimens and did not compromise maximum flexion angle compared to the uninjured controls (group 1) or the isolated tendon repair digits (group 2).     

Effect of pulley integrity on excursions and work of flexion in healing flexor tendons

We investigated the effect of incision of a single critical pulley on excursions and work of flexion in healing flexor tendons. Forty-two long toes from 21 white leghorn chickens were used as the experimental model. Gliding excursions of the flexor digitorum profundus tendons and work of flexion of the long toes were studied 8 weeks after tendon repair to determine the functions of the healed tendons in intact, incised, or enlarged A2 pulleys. Eleven additional chickens (22 long toes) were used to obtain tendon excursion measurements in normal chicken toes. At 8 weeks, gliding excursions were statistically smaller in the intact pulley group than in the incised or enlarged pulley groups; the excursions were 73% +/- 4% for the intact pulley group, 88% +/- 9% for the incised pulley group, and 91% +/- 8% for the enlarged sheath group compared with the normal group. Work of flexion of the toes in the intact pulley group was statistically greater than that in the incised or enlarged pulley groups. Excursion efficiency of the flexor tendons was not statistically different among the toes receiving different treatments in the pulley. The results of this study demonstrate that release of a single pulley after repair of the tendons in this area improved gliding excursions of the tendons and reduced resistance to motion of the repaired tendons, and provide support for partial A2 pulley incision after repair of the tendons in the area of the pulley.     

臂丛神经下干、内侧束部损伤133例的远期随访结果

目的观察臂丛神经下干、内侧束损伤患者术后的远期疗效。方法将133例臂丛下干、内侧束损伤患者分成神经断伤修复组40例,作神经端端缝合;神经断伤未修复组61例,未作处理;粘连松解组32例,行神经外松解术。术后随访2~14年,进行屈腕、屈指、分指并指检查及电生理检查。结果断伤未修复组无1例恢复功能。断伤修复组中8例的尺侧屈腕肌及指深屈肌肌力恢复至M3 ,但手内在肌功能未恢复。2例臂丛内侧束少部分神经断伤者在缝合神经的同时行神经松解,术后手内在肌肌力恢复至M3 。肌电图示肌肉强收缩时均为单纯-混合相。粘连松解组中75%(24/32)的手内在肌肌力恢复至M3 。结论(1)臂丛神经断裂不能直接修复者应作神经移位术。(2)神经直接修复者有31%恢复部分功能。(3)臂丛神经粘连松解者,有75%可恢复功能。     

Ruptured flexor tendon tenorrhaphies in zone II: repair and rehabilitation

Seven patients with ruptured flexor tenorrhaphies in zone II had surgical repair of the rupture and completed a second rehabilitation program of active flexion and extension exercises identical to that prescribed after the primary repair. The period between the primary repair and the rupture ranged from 14 to 72 days, with an average of 38 days. The period between the rupture and the secondary repair ranged between 1 and 14 days, with an average of 6 days. Four patients (57%) achieved good to excellent active motion at follow-up. These results are comparable to those obtained by patients with uncomplicated primary repairs that were treated early with passive motion exercises. We conclude that prompt repair of ruptured flexor tenorrhaphies and rehabilitation with active motion exercises is effective and that it should be considered before one chooses flexor tendon grafting.     

腱缝合后鞘内置入法在Ⅱ区屈肌腱修复中的临床应用

目的介绍用腱缝合后鞘内置入法，治疗Ⅱ区屈肌腱损伤的方法和疗效。方法按该法治疗屈肌腱损伤４６例７７指。伸直型１２例２６指：经原腱鞘伤口缝合肌腱，术毕将肌腱缝合部置于近侧健康鞘管内。屈曲型３４例５１指：在肌腱远断端以远约０．５ｃｍ处另作腱鞘切口，经此切口将损伤腱近端拉出进行缝合，术毕将腱缝合口置于远端切口和原伤口间的完整鞘管内。结果术后随访到３８例５９指，随访时间为２个月～３年，平均１年８个月。按ＴＡＭ评定法评定疗效，优级：３０指，良级：１７指，余为中差级；总优良率达到７９．７％。锐器切割伤４３指，疗效优良者４２指占９７．７％；合并腱鞘及周围组织损伤１６指，疗效优良者５指占３１．３％。结论该术式对单纯指屈肌腱损伤疗效满意，这可能和术时腱鞘损伤轻，肌腱缝合口被健康鞘管包绕后，有利于肌腱的内源性愈合并减少了外源性愈合的参与有关     

Flexor tendon rehabilitation in the 21st century: A systematic review

Study DesignSystematic review.IntroductionThe rehabilitation of patients following flexor tendon injury has progressed from immobilization to true active flexion with the addition of wrist motion over the last 75 years.Purpose of the StudyThis review specifically intended to determine whether there is evidence to support one type of exercise regimen, early passive, place and hold, or true active, as superior for producing safe and maximal range of motion following flexor tendon repair.MethodsThe preferred reporting items for systematic review and meta-analysis (PRISMA-P 2015) checklist was utilized to format the review. Both reviewers collaborated on all aspects of the research, including identifying inclusion/exclusion factors, search terms, reading and scoring articles, and authoring the paper. Articles were independently scored by each reviewer using the Structured Effectiveness Quality Evaluation Scale (SEQES).ResultsA total of nine intervention studies that included a rehabilitative comparison group were systematically reviewed: one pediatric, four comparing passive flexion protocols to place and hold flexion, and four comparing true active flexion to passive and/or place and hold flexion.DiscussionThis review provides moderate to strong evidence that place and hold exercises provide better outcomes than passive flexion protocols for patients with two to six-strand repairs. The studies included in this review suffered from methodological limitations including short timeframes for follow-up, unequal group distribution, and limited attention to repair site strength.ConclusionsBased on a lack of superior benefits following true active motion regimens, there is not sufficient evidence to support true active motion as an effective or preferable choice for flexor tendon rehabilitation at this time.     

Biomechanical characteristics of extensor tendon suture techniques

Despite their ease of exposure, extensor tendons can be difficult to handle and suture well. Compared with flexor repair, little is known about the various factors that affect the suturing of extensor tendons. The present study was designed to investigate several biomechanical parameters involved in extensor repair. All techniques studied shortened the tendon considerably and produced significant losses of flexion at the metacarpophalangeal and proximal interphalangeal joints. In addition, repairs achieved with all suture techniques were considerably weaker than those achieved when comparable techniques were used on flexor tendons. However, the Kleinert modification of the Bunnell technique provided the strongest sutures in extensor tendons, produced no gapping, caused the least worrisome loss of metacarpophalangeal and proximal interphalangeal flexion, and best approximated the results found in an idealized tendon-shortening model.     

Effect of synergistic wrist motion on adhesion formation after repair of partial flexor digitorum profundus tendon lacerations in a canine model in vivo.

BACKGROUND: Therapy employing passive finger flexion and active finger extension with the wrist fixed in flexion is commonly used after flexor tendon repair. However, this method of rehabilitation may not produce full tendon excursion because of buckling of the tendon within its sheath with passive flexion. Studies of cadavera suggest that the use of synergistic wrist and finger motion may improve tendon gliding. The purpose of this study was to assess the effects of passive digital motion, performed with either wrist fixation or synergistic wrist motion, on adhesion and gap formation after flexor tendon repair. METHODS: Sixty-six dogs were randomly allocated to two groups. In each group, two flexor digitorum profundus tendons of one forepaw were partially (80%) lacerated and then repaired with a modified Kessler suture. In each group, a different postoperative therapy (wrist fixation or synergistic motion) was performed twice daily. The dogs were killed at one week, three weeks, or six weeks after surgery, and the repaired tendons were evaluated to determine the adhesion grade and adhesion breaking strength. RESULTS: The synergistic motion group had a significantly lower adhesion grade and significantly less adhesion breaking strength than the wrist fixation group at three and six weeks (p < 0.05). At one week, there was no significant difference between the two therapy groups (p > 0.05). CONCLUSIONS: Passive digital flexion and extension with synergistic wrist motion was an effective therapy after repair of partial zone-2 lacerations in a canine model.     

Aggressive active mobilization following zone II flexor tendon repair using a two-strand heavy-gauge locking loop technique

 In vitro and in vivo experimental studies have shown that a new two-strand technique increases the tensile strength of flexor tendon repair and eliminates gap formation at the healing repair site. The purpose of the current study was to clinically evaluate the new technique, followed by an aggressive active mobilization program. Seven digits with zone II flexor tendon lacerations were treated using the technique, employing a heavy (2-0) braided polyester suture. The patients were encouraged to perform active mobilization of the injured digits by themselves with almost a full range of flexion and extension after they were instructed by the surgeon for few days from the first postoperative day. All patients were followed up for at least 6 months, except for one, with whom contact was lost in 14 weeks postoperatively. Six of the seven digits were evaluated as excellent in 6 months by the original Strickland criteria, thus showing that the combination of the new repair technique and aggressive active mobilization is effective for zone II flexor tendon repair. Received: August 22, 2001 / Accepted: March 19, 2002