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.     

A biomechanical study of plate versus intramedullary devices for midshaft clavicle fixation

Background

Our understanding of finger functionality associated with the specific muscle is mostly based on the functional anatomy, and the exact motion effect associated with an individual muscle is still unknown. The purpose of this study was to examine phalangeal joints motion of the index finger generated by each extrinsic muscle.

Methods

Ten (6 female and 4 male) fresh-frozen cadaveric hands (age 55.2 ± 5.6 years) were minimally dissected to establish baseball sutures at the musculotendinous junctions of the index finger extrinsic muscles. Each tendon was loaded to 10% of its force potential and the motion generated at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints was simultaneously recorded using a marker-based motion capture system.

Results

The flexor digitorum profundus (FDP) generated average flexion of 19.7, 41.8, and 29.4 degrees at the MCP, PIP, and DIP joints, respectively. The flexor digitorum superficialis (FDS) generated average flexion of 24.8 and 47.9 degrees at the MCP and PIP joints, respectively, and no motion at the DIP joints. The extensor digitorum communis (EDC) and extensor indicis proprius (EIP) generated average extension of 18.3, 15.2, 4.0 degrees and 15.4, 13.2, 3.7 degrees at the MCP, PIP and DIP joints, respectively. The FDP generated simultaneous motion at the PIP and DIP joints. However, the motion generated by the FDP and FDS, at the MCP joint lagged the motion generated at the PIP joint. The EDC and EIP generated simultaneous motion at the MCP and PIP joints.

Conclusion

The results of this study provide novel insights into the kinematic role of individual extrinsic muscles.     

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.     

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).     

Impact of flexor digitorum superficialis on gliding function of the flexor digitorum profundus according to regions in zone II

PURPOSE: Structures and gliding characteristics of the flexor tendons vary remarkably according to regions of zone II in the hand. We studied the impact of the flexor digitorum superficialis (FDS) on the work of flexion and excursion efficiency of the flexor digitorum profundus (FDP) tendon in different regions of zone II. METHODS: Twenty-one fresh-frozen human fingers were used as an experimental model. The FDP was pulled to flex the finger with a tensile machine. The work of flexion of the finger and gliding excursion of the tendon were recorded in the fingers with the FDS intact, after excision of the FDS proximal to, under, or distal to the A2 pulley. RESULTS: The FDS tendon exerts notably different effects on the work of flexion and excursion efficiency of the FDP in subregions of zone II. Removal of the FDS under the A2 pulley affected the FDP most manifestly, causing a 12% decrease in the work of flexion and a loss of the excursion efficiency at the metacarpophalangeal joint. Removal of the FDS proximal to the A2 pulley had a less notable effect on the work of flexion. Removal of the FDS distal to the pulley did not markedly alter the biomechanics of the FDP. CONCLUSIONS: Removal of the FDS tendon in the area of the A2 pulley reduces the work of flexion most notably and causes a loss of excursion efficiency. Removal of the FDS tendon distal to the A2 pulley does not change the work of flexion, and removal of the FDS tendon proximal to the A2 pulley has a notable but less pronounced effect on the FDP tendon.     

Excursion of the flexor digitorum profundus tendon: a kinematic study of the human and canine digits

The most common problem following primary flexor tendon repair is the failure of the tendon apparatus to glide, secondary to the formation of adhesions. Early motion following tendon repair has been shown to be effective in reducing adhesions between the tendon and the surrounding sheath. Therefore, it is important to determine the amount of flexor tendon excursion along the digit during joint motion. In this study, the excursion between the flexor digitorum profundus (FDP) tendon and the sheath was examined in both human and canine digits. Based on roentgenographic measurements and joint kinematic analysis, the motion of the bones, the FDP tendon, and the sheath were measured with respect to joint rotations. It was found that the canine flexor tendon apparatus behaved similarly to that of the human for the motions studied. The amount of tendon excursion was very small in regions distal to the joint in motion (approximately 0.1 mm/10 degrees of joint rotation). There was little displacement of the sheath (0.2-0.3 mm), except at the metacarpal joint region during metacarpophalangeal (MCP) joint motion and at the proximal interphalangeal (PIP) joint region during PIP joint motion. Tendon excursion relative to the tendon sheath was the largest in zone II during PIP joint rotation (1.7 mm/10 degrees of joint rotation). These results suggest that PIP joint motion may be most effective in reducing adhesions following tendon repair in zone II.     

Ultrasound assessment of the motion patterns of human flexor digitorum superficialis and profundus tendons with speckle tracking

The purposes of our study were to correlate ultrasonographically measured and joint angle estimated excursions of the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons of the hand and to estimate the relative motion of FDS and FDP while gripping cylinders of standard diameter in normal human subjects. Thirty wrists from 15 human subjects were imaged with an ultrasound scanner. Speckle tracking was used to measure the excursion of the FDS and FDP tendons. The tendon excursions necessary to grip three differently sized acrylic tubes were measured and correlated with the corresponding finger joint angles. The FDP/FDS excursion ratio was calculated. The Pearson's correlation coefficient between the FDS excursion and MP + PIP joint angle was 0.61. The Pearson's correlation coefficient between the FDP + FDS excursion and the DIP + PIP + MP joint angle was 0.67. The FDP/FDS excursion ratio was smaller for larger excursions (gripping a smaller diameter tube) and larger for small excursions (gripping a larger diameter tube, P < 0.01). These data suggest that speckle tracking may be a useful method to discriminate the relative motion of flexor tendons, which in turn may be relevant in evaluating tendon function, for example after tendon injury. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1465–1469, 2011     

Partially retained small finger flexor digitorum profundus function despite complete tendon loss in the forearm

A case of traumatic laceration of the small finger flexor digitorum profundus (FDP) tendon in the distal forearm with retained partial active flexion at the small finger distal interphalangeal joint (DIP) joint is described. Tendinous interconnections between the ring and small FDP tendons and lumbrical muscles may permit partial FDP function at the DIP joint despite a complete deficit of the proximal tendon.     

Effects of superficialis tendon repairs on lacerated profundus tendons within or proximal to the A2 pulley: an in vivo study in chickens

PURPOSE: In a flexor tendon injury model in chickens we undertook a study to evaluate effects of the flexor digitorum superficialis (FDS) tendon repairs on excursions, work of flexion, and adhesions of the repaired flexor digitorum profundus (FDP) tendon after their injuries within or proximal to the equivalent of the A2 pulley and early tendon motion. METHODS: Thirty-five leghorn chickens were divided into 3 groups. In group 1 the FDS and FDP tendons of the long toes on both sides were transected in the area covered by the pulley. In group 2 the tendons were transected proximal to the pulley. In the first 2 groups, both tendons were repaired on the left feet, and only the profundus was repaired with superficialis excision on the right. The operated toes underwent simulated passive flexion for 3 weeks and results were evaluated 8 weeks after surgery. Chickens in group 3 were unoperated and served as the controls. RESULTS: When the tendons were cut within the pulley the FDP excursions and work of flexion were significantly better in the toes in which the FDS was excised than in those with both tendon repairs. When they were cut proximal to the pulley the repairs of both tendons had outcomes similar to that with excision of the FDS. Adhesions were more severe when both tendons were repaired under the pulley as compared with those after repair of a single tendon. CONCLUSIONS: This study showed different effects of the surgical repair or excision of the FDS on the FDP tendon within or proximal to a major pulley. Repair of both tendons worsens the gliding of the FDP tendon and increases adhesions within the major pulley; however, repair of both tendons yields outcomes equivalent to that after repair of only the FDP tendon proximal to the pulley.     

Biomechanical analyses of the human flexor tendon adhesion models in the hand: A cadaveric study

Patients with longstanding trigger finger may develop flexion contracture at the proximal interphalangeal (PIP) joint that persists even after division of the A1 pulley. The purpose of this study was to explore the hypothesis that flexion deformity of the PIP joint in advanced trigger finger is caused by severe adhesion between the flexor digitorum superficialis (FDS) and the flexor digitorum profundus (FDP) tendons. Ten freshly frozen cadaveric hands were used in the experiments. After preparation of the extrinsic flexor, extrinsic extensor, and intrinsic muscle tendons, we applied weights to the flexor tendons and minimal tension to the extrinsic extensor and intrinsic muscle tendons. We then measured the initial flexion angles of the metacarpophalangeal (MCP) and PIP joints. Next, we measured the flexion angles of the MCP and PIP joints as increasing tension was applied to the extrinsic extensor and intrinsic muscle tendons, respectively. We repeated these experiments after constructing flexor tendon adhesion model. The initial flexion angles of the MCP and PIP joints were greater in the adhesion model, as were the average tensions required for full extension of these joints. Our results suggest that adhesion between two flexor tendons contributes to progression of flexion deformity in the PIP joint. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:717–725, 2015.     

Use of a relative motion flexion orthosis after epitendinous zone II flexor tendon repair: A case report

Study designCase reportIntroductionRelative motion flexion (RMF) orthoses are emerging as an option for early active motion (EAM) postoperatively.Purpose of the studyTo describe the rationale and implementation of an RMF orthosis to manage a patient after partial zone II epitendinous flexor tendon repairs.MethodsThis case involves a female who sustained partial flexor tendon lacerations to her middle finger in zone II, 60% flexor digitorum superficialis (FDS) and 90% flexor digitorum profundus (FDP). After epitendinous repair she was referred to therapy for EAM with a no orthosis request. The unusual circumstances prompted the therapist, concerned about the risk of tendon rupture to engage in discussion with the surgeon. Following discussion, a decision was made to use an RMF orthosis for controlled EAM to protect the epitendinous zone II FDS and FDP repairs. Outcomes of range of motion (ROM), total active motion (TAM), %TAM, grip, and quickDASH are reported.ResultsNeither the FDP or FDS tendons ruptured, nor were there any joint contractures. “Good” %TAM outcomes were achieved at 12-week postoperatively. Quick DASH scores improved 61 points indicating a clinically meaningful difference of improved function.DiscussionThe lack of a multi-strand core suture repair is unusual in combination with EAM. The positive outcomes reported in this single patient have raised questions about the protective benefit of the RMF orthosis when used with a zone II epitendinous repair of a 90% FDP laceration. Epitendinous repair of a partial (60%) FDS injury, however, is not uncommon and often not repaired at all.ConclusionsIn this single case report the epitendinous repairs of zone II 90% FDP and 60% FDS with digital nerve involvement were successfully managed with an RMF only orthosis. The use of EAM with an epitendinous repair is in conflict to the current surgical and therapy literature.     

Ⅱc区早期修复深浅指屈肌腱后A2滑车的处理

目的 探讨指屈肌腱Ⅱc区单纯切割伤双腱修复后A2滑车不同处理对肌腱功能的影响。方法 将21只来亨鸡随机分为二组,以鸡双足中趾为手术趾,在每趾肌腱均造成屈趾浅肌腱(FDS)、屈趾深肌腱(FDP)单纯切割伤,并行双腱修复。A组:A2滑车完整;B组:A2滑车切开;C组:A2滑车扩大。术后10周末处死动物,对鸡趾分别进行生物力学和形态学评定。结果 Ⅱc亚区屈肌腱单纯切割伤早期双腱修复后,A2滑车切开组与A2滑车扩大组的肌腱滑动距离明显大于A2滑车完整组,屈曲功则明显小于A2滑车完整组,而A2滑车切开组与A2滑车扩大组之间无论是肌腱滑动距离还是屈曲功在统计学上则无明显差异(P>0.05)。结论 临床上Ⅱc亚区FDS、FDP腱损伤早期双腱修复后作A2滑车切开或扩大成形术,有利于肌腱滑动和功能恢复。     

Flexor digitorum profundus tendon excursions during controlled motion after flexor tendon repair in zone II: a prospective clinical study.

Intratendinous metal markers were used to study flexor digitorum profundus tendon excursions during early controlled motion with dynamic flexion traction and to evaluate their significance for results after flexor tendon repair in zone II. The mean excursion was 1 mm along the middle phalanx and 5.6 mm along the proximal phalanx. This corresponded to a mean excursion per 10 degrees of controlled distal and proximal interphalangeal joint motion of 0.3 and 1.2 mm, respectively. Compared to active motion, controlled motion of the distal interphalangeal joint mobilized the tendon with an efficiency of 36% and controlled motion of the proximal interphalangeal joint mobilized the tendon with an efficiency of 90%. Controlled-motion excursions induced by the distal interphalangeal joint along the middle phalanx had little influence on subsequent active range of motion in the distal interphalangeal joint, whereas excursions along the proximal phalanx (for which the proximal interphalangeal joint was largely responsible) did have a significant influence on subsequent total active interphalangeal range of motion.     

Zone I flexor tendon injuries

Zone I flexor tendon injuries entail injuries to the flexor digitorum profundus (FDP) tendon. These injuries occur distal to the superficialis insertion over the middle phalanx or proximal distal phalanx, and as such are isolated injuries to the FDP. The mechanism most commonly is closed avulsion from the distal phalanx or a laceration, but other mechanisms such as open avulsion or crush injury can occur. On physical examination, the cascade of the fingers will be disrupted, and distal interphalangeal (DIP) joint flexion must be isolated to determine if the FDP tendon is continuous, as other mechanisms are present to enable finger flexion at the other joints.     

Flexor digitorum profundus tendon tension during finger manipulation.

Abstract The purpose of this study was to measure the tension in the flexor digitorum profundus (FDP) tendon in zone II and the digit angle during joint manipulations that replicate rehabilitation protocols. Eight FDP tendons from eight human cadavers were used in this study. The dynamic tension in zone II of the tendon and metacarpophalangeal (MCP) joint angle were measured in various wrist and digit positions. Tension in the FDP tendon increased with MCP joint extension. There was no tension with the finger fully flexed and wrist extended (synergistic motion), but the tendon force reached 1.77 +/- 0.43 N with the MCP joint hyperextended 45 degrees with the distal interphalangeal and proximal interphalangeal joints flexed. The combination of wrist extension and MCP joint hyperextension with the distal interphalangeal and proximal interphalangeal joints fully flexed, what the authors term "modified synergistic motion," produced a modest tendon tension and may be a useful alternative configuration to normal synergistic motion in tendon rehabilitation.     

近节指间关节处屈肌腱腱鞘的功能研究

目的探索Ａ３、Ｃ１和Ｃ２滑车对指深屈肌腱及近节指间关节活动的影响。方法采用１０只尸体手示、中、环指，将掌指关节及远节指间关节固定后，进行以下４个阶段的实验：（１）腱鞘完整；（２）Ａ３滑车切除；（３）Ａ３及其近端切开；（４）Ａ４与Ａ２滑车间的腱鞘切开。牵拉指深屈肌腱至近节指间关节屈曲到１１０度时，测量指深屈肌腱的滑动距离。用方差分析法比较各实验阶段结果的差异。结果Ａ３及其周围腱鞘切除后，指深屈肌腱的滑动距离显著增加（Ｐ＜０．０５或＜０．０１），并出现明显的“弓弦＂状畸形。结论研究结果提示临床上行肌腱修复时应注意保留近节指间关节附近滑车的功能。     

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.     

Gliding resistance after FDP and FDS tendon repair in zone II

Many suture techniques have been described for flexor tendon repair. While many of these sutures have been tested and used clinically, the interaction between repairs of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) in the same digit has not been rigorously examined. Moreover, while much data are available on the mechanical properties of various suture techniques for FDP repair, much less is known about the mechanical performance of FDS repairs during motion of tendons.

To make up for this lack of information, we measured the gliding resistance of the repaired FDP tendon, as compared to different FDS tendon repairs in a human cadaver model. The FDP tendon was repaired with a modified Kessler technique, while the FDS was repaired with a modified Kessler (n = 10), Becker (n = 10), or a new double running zig-zag suture (n = 10). The modified Kessler repair had a threefold increase from normal gliding resistance, the Becker repair increased twofold, and the zig-zag repair increased twofold. The peak gliding resistance increased twofold with a modified Kessler repair, 2.5-fold with a Becker repair, and 2.5-fold with a zig-zag repair.     

Gliding resistance after FDP and FDS tendon repair in zone II: an in vitro study

Many suture techniques have been described for flexor tendon repair. While many of these sutures have been tested and used clinically, the interaction between repairs of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) in the same digit has not been rigorously examined. Moreover, while much data are available on the mechanical properties of various suture techniques for FDP repair, much less is known about the mechanical performance of FDS repairs during motion of tendons. To make up for this lack of information, we measured the gliding resistance of the repaired FDP tendon, as compared to different FDS tendon repairs in a human cadaver model. The FDP tendon was repaired with a modified Kessler technique, while the FDS was repaired with a modified Kessler (n = 10), Becker (n = 10), or a new double running zig-zag suture (n = 10). The modified Kessler repair had a threefold increase from normal gliding resistance, the Becker repair increased twofold, and the zig-zag repair increased twofold. The peak gliding resistance increased twofold with a modified Kessler repair, 2.5-fold with a Becker repair, and 2.5-fold with a zig-zag repair.     

Comparative flexor tendon excursion after passive mobilization: an in vitro study.

Two experimental studies were conducted to investigate flexor tendon excursions. In the first study, tendon excursions due to passive joint motion in various loading condition were evaluated. In the second study, the efficacy of a new technique that used synergistic wrist motion (S-splint) was compared with the traditional dorsal splinting methods: the Kleinert splint (K-splint) and the Brooke Army Hospital/Walter Reed modified Kleinert splint with a palmar bar (P-splint). The results of these studies question the anticipated tendon excursion associated with postoperative splinting. They demonstrated that the measured tendon excursion under a condition of low tendon tension was almost half that of theoretically predicted values. In zone II, the magnitude of excursion introduced by the three mobilization methods were in descending order: S-splint, P-splint, K-splint (p less than 0.05). Differential tendon excursion between the flexor digitorum profundus and the flexor digitorum superficialis had a mean value of 3 mm and was not significantly different among the three methods. Passive proximal interphalangeal joint motion was the most effective means of providing increased amplitude of tendon gliding in zone II. Passive distal interphalangeal joint motion did not increase excursion in zone II as much as had been predicted.