Avulsion injuries of the flexor digitorum profundus tendon

Avulsions of the flexor digitorum profundus tendon may involve tendon retraction into the palm and fractures of the distal phalanx. Although various repair techniques have been described, none has emerged as superior to others. Review of the literature does provide evidence-based premises for treatment: multi-strand repairs perform better, gapping may be seen with pullout suture-dorsal button repairs, and failure because of bone pullout remains a concern with suture anchor methods. Clinical prognostic factors include the extent of proximal tendon retraction, chronicity of the avulsion, and the presence and size of associated osseous fragments. Patients must be counseled appropriately regarding anticipated outcomes, the importance of postoperative rehabilitation, and potential complications. Treatment alternatives for the chronic avulsion injury remain patient-specific and include nonsurgical management, distal interphalangeal joint arthrodesis, and staged reconstruction.     

Bone suture anchors versus the pullout button for repair of distal profundus tendon injuries: a comparison of strength in human cadaveric hands.

Avulsion or distal tendon laceration of flexor digitorum profundus (FDP) is classically repaired to the base of the distal phalanx via a pullout suture over a button. Bone suture anchors, used extensively in other surgical areas, have recently been proposed for reattachment of the FDP to the distal phalanx. The FDP tendons of the index, long, and ring fingers in 9 fresh frozen cadeveric hands were randomized to 1 of 3 repair techniques after simulated distal avulsion injuries. These were the pullout button using 3-0 monofilament nylon in a 2-strand Bunnell suture pattern, the 1.8 mm Mini QuickAnchor (Mitek Products, Norwood, MA) using 3-0 braided polyester in a 2-strand Bunnell suture pattern, and the Mitek micro anchor using 3-0 braided polyester with a modified 4-strand Becker suture pattern. Nine specimens were loaded to failure, noting maximum load and mode of failure. The 1.3 mm Micro QuickAnchor (Mitek) technique (69.6 +/- 10.8 N) was significantly stronger than the pullout button (43.3 +/- 4.8 N) or the Mini anchor technique (44.6 +/- 12.7 N). The Micro bone suture anchor provides a stronger tendon to bone repair than the pullout button or the Mini anchor. Given the disadvantages of the pullout button, the Micro bone suture anchor with the modified Becker technique is worth consideration as an alternative method to repair distal FDP avulsions.     

Distal attachment of flexor tendon allograft: A biomechanical study of different reconstruction techniques in human cadaver hands

We compared the mechanical force of tendon‐to‐bone repair techniques for flexor tendon reconstruction. Thirty‐six flexor digitorum profundus (FDP) tendons were divided into three groups based upon the repair technique: (1) suture/button repair using FDP tendon (Pullout button group), (2) suture bony anchor using FDP tendon (Suture anchor group), and (3) suture/button repair using FDP tendon with its bony attachment preserved (Bony attachment group). The repair failure force and stiffness were measured. The mean load to failure and stiffness in the bony attachment group were significantly higher than that in the pullout button and suture anchor groups. No significant difference was found in failure force and stiffness between the pullout button and suture anchor groups. An intrasynovial flexor tendon graft with its bony attachment has significantly improved tensile properties at the distal repair site when compared with a typical tendon‐to‐bone attachment with a button or suture anchor. The improvement in the tensile properties at the repair site may facilitate postoperative rehabilitation and reduce the risk of graft rupture. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1720–1724, 2013     

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.     

A biomechanical study of reattachment versus distal multistrand repair in distal division of the flexor digitorum profundus

Distal division of the flexor digitorum profundus (FDP) within 10mm of its insertion is commonly treated in the same manner as avulsion of the FDP, using the "button" technique or bone suture anchor fixation. Button and bone suture anchor fixation techniques have been associated with significant complications. Importantly, both lead to shortening of the FDP which may cause flexion contracture at the distal interphalangeal joint. This study compared the breaking strength of a multistrand distal suture with reattachment using the "button-on-the-nail" technique in a laboratory cadaver model of distal FDP division. The data showed that multistrand distal suture repair was at least as strong as reattachment and has the theoretical advantage of avoiding some of the acknowledged complications of reattachment techniques.     

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.     

Reconstruction of Neglected Flexor Hallucis Longus Tendon Rupture: A Case Report

Isolated rupture of the flexor hallucis longus tendon is an unusual injury. We present the case of a neglected flexor hallucis longus tendon closed traumatic rupture at the plantar aspect of the first phalangeal head of the great toe in a middle-age male. The injury occurred while he was dancing. Because end-to-end tendon suture was impossible, the ensuing gap was repaired using a free plantaris tendon graft. We present the operative repair benefit of the flexor hallucis longus tendon rupture to regain the function and strength of the interphalangeal joint of the hallux, avoid extension of the distal phalanx, and maintain the longitudinal arch of the foot.     

The morbidity of the button-over-nail technique for zone 1 flexor tendon repairs. Should we still be using this technique?

The button-over-nail technique is commonly used to fix the core suture to the distal phalanx for flexor digitorum profundus repairs in zone 1. We report a retrospective study of 23 consecutive patients who had a repair of the flexor digitorum profundus tendon in zone 1 using the button-over-nail technique. Fifteen patients experienced a complication, of which ten were directly related to the button-over-nail technique. Complications included nail deformities, fixed flexion deformities of the distal interphalangeal joint, infections and prolonged hypersensitivity. Two patients required amputation of the fingertip. We recommend that the button-over-nail technique should be avoided or used only with caution and with close attention to the details of the technique.     

Effect of suture locking and suture caliber on fatigue strength of flexor tendon repairs

The objectives of this cadaveric study were 2-fold: to determine the effect of different locking configurations on the cyclical fatigue strength of flexor tendon repairs and to assess the differences between each repair when a 3-0 or 4-0 suture is used. One hundred twenty flexor digitorum profundus tendons were cut and repaired using nonlocked, simple locked, and cross-stitch locked variations of 2- and 4-strand flexor tendon repairs. Using an incremental cyclical loading protocol we performed 10 trials of each repair with both 3-0 and 4-0 sutures and analyzed the number of Newton-cycles to failure using a 3-way ANOVA. The use of a 3-0 suture led to a 2- to 3-fold increase in fatigue strength in all repairs tested and the fatigue strength of the 4-strand repairs was significantly greater than the 2-strand repairs. All repairs performed with 4-0 suture failed by suture rupture. Of the 3-0 suture repairs, the three 2-strand repairs and the 4-strand cross-stitch locked repair failed by suture rupture. In contrast, 6 of 10 of the 4-strand simple locked and nonlocked repairs failed by suture pullout. There was no significant difference in fatigue strength between the 2 locked and the nonlocked 2-strand repairs using either 3-0 or 4-0 suture. There also was no significant difference in holding capacity or fatigue strength between the simple locked or nonlocked 4-strand repairs. However, the 4-strand cross-stitch locked repair with a 3-0 suture had significantly improved fatigue strength and holding capacity compared with the other repairs tested. Based on the consistently inferior biomechanical performance of 4-0 suture, we recommend that 3-0 suture be considered for 2- or 4-strand tendon repairs when early active motion is planned. The orientation of the transverse and longitudinal components of simple locked repairs did not significantly influence their holding capacity or fatigue strength. The cross-stitch type of locked repair provides better holding capacity and fatigue strength compared with simple locked or nonlocked 4-stranded flexor tendon repairs.     

Biomechanic comparison of the Teno Fix tendon repair device with the cruciate and modified Kessler techniques

PURPOSE: To compare the mechanical behavior of a novel internal tendon repair device with commonly used 2-strand and 4-strand repair techniques for zone II flexor tendon lacerations. METHODS: Thirty cadaveric flexor digitorum profundus tendons were randomized to 1 of 3 core sutures: (1) cruciate locked 4-strand technique, (2) modified Kessler 2-strand core suture technique, or (3) Teno Fix multifilament wire tendon repair device. Each repair was tested in the load control setting on a Instron controller coupled to an MTS materials testing machine load frame by using an incremental cyclic linear loading protocol. A differential variable reluctance transducer was used to record displacement across the repair site. Cyclic force (n-cycles) to 1-mm gap and repair failure was recorded using serial digital photography. RESULTS: There was no significant difference in differential variable reluctance transducer displacement between the cruciate, modified Kessler, and Teno Fix repairs. The cruciate repair had greater resistance to visual 1-mm repair-site gap formation and repair-site failure when compared with the Kessler and Teno Fix repairs. No significant difference was found between the modified Kessler repair and the Teno Fix repair. In all specimens, the epitenon suture failed before the core suture. Repair failure occurred by suture rupture in the 7 cruciate specimens that failed, with evidence of gap formation before failure. Seven of 10 modified Kessler repairs failed by suture rupture. All of the Teno Fix repairs failed by pullout of the metal anchor. CONCLUSIONS: The Teno Fix repair system did not confer a mechanical advantage over the locked cruciate or modified Kessler suture techniques for zone II lacerations in cadaveric flexor tendons during cyclic loading in a linear testing model. This information may help to define safe boundaries for postoperative rehabilitation when using this internal tendon repair device.     

Limitation of flexor tendon excursion by heterotopic ossification after isolated flexor tendon laceration.

A patient, one year after flexor digitorum superficialis/profundus repair in the left index finger, was diagnosed with heterotopic ossification involving the palmar surface of the proximal phalanx creating a secondary proximal interphalangeal joint contracture. A Compass PIP Hinge facilitated the treatment. Flexor tendon excursion improved, and active range of motion increased from 60 to 90 degrees before surgery to 30 to 105 degrees 20 months after surgery. Ectopic bone involvement of the hand is rare. This article reports a successful treatment for a unique complication of flexor injury and repair.     

A technique for re-insertion following flexor tendon injuries in zone 1 using Mitek bone anchors

A technique for re-insertion of flexor digitorum profundus to the distal phalanx using Mitek bone anchors is described. In our series of seven procedures, there was no rupture of the repair. Internal fixation with Mitek bone anchors is reliable and has two main advantages of having no external component (e.g. button) and facilitating early mobilization.     

双套圈经隧道交叉加压缝合法用于指伸肌腱止点重建

目的 介绍一种末节指伸肌腱止点重建的方法.方法 克氏针固定远侧指间关节,肌腱两侧套圈缝合,经末节指骨基底的横行隧道交叉至对侧.两侧套线各分出1股向近侧返折后会合,于肌腱背侧中线做套圈缝合.两侧剩余的套线于肌腱背侧直接打结.结果 术后随访时间为5个月至2年,无一例发生肌腱断裂和肌腱粘连.远侧指间关节活动度:0°～70°18例,0°～60°17例,0°～50°4例.按TAM系统评定方法评定:优25例,良14例;优良率为100%结论采用双套圈经隧道交叉加压缝合法重建指伸肌腱止点,操作简单,疗效可靠.     

The use of Teno Fix tendon repair device in a patient with multiple flexor tendon ruptures

Flexor tendon laceration repairs remain challenging despite numerous advances in hand surgery. Although progress on this vital subject matter has been achieved, there continues to be discussion over which surgical technique produces the optimal result. Currently there are several recommended surgical repair options for the lacerated flexor tendon. However, these repairs continue to have possible significant complications including adhesions, decreased range of motion, gapping, and post operative rupture. Stainless steel suture has long been known as an option for flexor tendon repair. Stainless steel suture demonstrates one of the highest tensile strength sutures. However until recently, stainless steel suture placement for flexor tendon repairs was technically problematic. This case study discusses an additional option for repairing lacerated flexor tendons using an advanced stainless steel tendon repair system.     

Zone I flexor digitorum profundus repair: an ex vivo biomechanical analysis of tendon to bone repair in cadavera

PURPOSE: Biomechanical studies of standard flexor digitorum profundus (FDP) tendon to bone repairs show ultimate strengths greater than the applied loads of early motion rehabilitation protocols. Strain data, however, indicate the potential for significant repair site gapping under these physiologic loads. Gaps in excess of 3 mm have been shown to prevent the time accrual of strength in midsubstance tendon repairs and may prevent the restoration of the normal architecture of the tendon-bone interface. Improving the time-zero tensile properties of FDP insertion site repairs may help obviate these issues and improve clinical outcomes. The purpose of this study was to evaluate the ex vivo biomechanical properties of 2 new repair techniques in comparison with the standard FDP tendon to distal phalanx cortical surface repair. METHODS: Thirty human cadaver FDP tendons were released from their insertion sites by sharp dissection and repaired to bone using 1 of 3 repair techniques. Load to failure testing was performed with a servohydraulic materials-testing system (model 8500R; Instron, Canton, MA) analyzing ultimate force, strain at 20 N, rigidity, force to 2-mm gap formation, and displacement at failure. RESULTS: The results of the failure tests indicate that repairs performed with the addition of a peripheral suture had a greater ultimate force, had increased resistance to gap formation, and had increased rigidity and decreased strain at 20 N compared with the tunnel-only and volar cortical surface to the distal phalanx repairs. Although there were no statistically significant differences in ultimate force or rigidity between the tunnel-only and volar cortical surface repairs, the tunnel-only repairs showed lower strain values and increased values for resistance to 2-mm gap formation when compared with the volar cortical surface repairs. There were no differences among any of the repair groups with regard to the magnitude of tendon displacement from the repair site at failure. CONCLUSIONS: The addition of a peripheral suture to the FDP tendon to bone tunnel repair construct improves the time-zero tensile properties as evidenced by statistically significant increases in ultimate force, rigidity, and resistance to gap formations of 2 mm. In comparison with a volar cortical surface repair, the bone tunnel-only repairs were effective at decreasing the amount of repair site strain during applied loads of 20 N. If these improved time-zero tensile properties persist during the early stages of healing, they may help decrease the incidence of repair-site gap formation associated with the forces of early motion rehabilitation protocols.     

Repair of flexor digitorum profundus tendon avulsions from bone: an ex vivo biomechanical analysis

Avulsions or distal transections of the flexor digitorum profundus tendon are typically repaired by direct suture of the tendon stump to the distal phalanx. The optimal repair technique to withstand in vivo rehabilitation forces is unknown. Our objective was to determine the time-zero tensile mechanical properties of 4-strand tendon-bone repair site constructs performed with 3-0 and 4-0 sutures and with modified Kessler and modified Becker grasping techniques. We hypothesized that the 3-0 modified Becker grasping suture technique not described previously for the reattachment of tendon to bone would show improved biomechanical properties compared with the 4-0 or modified Kessler techniques. All modified Kessler repairs failed by suture pullout from the tendon, whereas all modified Becker repairs failed by rupture of the suture at the tendon-bone junction. Although the 3-0 modified Becker repair group showed greater ultimate force then the other groups (p <.01), tendon-bone gap observed did not differ markedly between Becker or Kessler groups. Neither suture caliber nor repair technique had a notable effect on strain at 20-N force, suggesting that early gap formation at the tendon-bone repair site may occur regardless of technique.     

Pulp tissue anchor repair for the zone I flexor tendon injury: introduction of a new and cost-effective technique

Background

Flexor digitorum profundus tendon (FDP) injury in zone I is one of the common findings in the hand examination when a patient presents with a hand trauma. Various repair techniques have been described in the literature with its own advantages and disadvantages. In this article, the senior author describes a new pulp tissue anchor repair for the zone I FDP injuries.

Methods

After a careful dissection of the proximal end of the tendon, a fish-mouth incision is made on the distal pulp of the finger. A modified Kessler stitch is placed in the terminal end of the tendon.Then, the suture is passed through the periosteum and the fibrous bands of the pulp using the wide-bore needle. A knot is secured in the fish-mouth incision, and the skin is closed.

Results

This technique was used in closed FDP avulsions (n?=?19), two-stage tendon repairs using palmaris longus (n?=?24), with the remainder being open injuries (n?=?70). There were 18 patients who presented with a flexion contracture at the distal interphalangeal joint level and two cases of rupture in zone I divisions.

Conclusion

The technique described is cost effective as there is no need for the use of drills, K-wires, suture anchors or intraoperative imaging. Furthermore, it is simple and quick to perform. The repair is strong, and risk of infection is minimal as bony cortices are not breached. Minimal assistance is required, and all these factors combine to reduce the cost of the procedure. Level of Evidence: Level IV, therapeutic study.     

Closed reduction and percutaneous pinning of fractures of the proximal phalanx

This study reports the results of 12 unstable extraarticular fractures of the proximal phalanx treated with transarticular intramedullary Kirschner wires. Early proximal interphalangeal joint motion was allowed and all patients achieved uneventful union, with an average total active motion of 265 degrees. Objective physical assessment revealed one significant flexion contracture, one flexor tendon adhesion and one significant rotational deformity. Excellent results were observed in ten of the 12 patients.     

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.     

Zone I flexor profundus tendon repair in children 5-10 years of age using 3 "figure of eight" sutures followed by immediate active mobilization

A review of the English medical literature over the last 20 years reporting on flexor profundus lacerations revealed only 55 reported cases of zone I flexor profundus lacerations in children. The standard repair technique in young children (5-10 years of age) has been either tendon reinsertion into bone (usually Bunnell technique) for distal zone I injuries or a 2-strand repair (usually modified Kessler technique) for proximal zone I injuries. We report on 22 children (5-10 years of age) with zone I flexor profundus tendon lacerations (10 children had distal zone I injury and 12 had proximal zone I injury) repaired with a 6-strand technique (3 separate "figure of 8" sutures) followed by early postoperative active mobilization. There were no ruptures. Using the Strickland and Glogovac criteria (on the basis of the net active motion of both the interphalangeal joints), all children qualified for an excellent outcome. However, using Moremen and Elliot criteria (on the basis of the net active motion of the distal interphalangeal joint only), 11 children had an excellent outcome, 3 had a good outcome, and 8 had a fair outcome. Our results were compared with previously reported series. It was concluded that the 6-strand figure of 8 suture technique may be used in pediatric zone I injuries and it is strong enough to allow safe early postoperative active mobilization in the 5- to 10-year age group children.