Reconstruction of the extensor central slip using a distally based flexor digitorum superficialis slip

Stack versus Te Technique for Central Slip Reconstruction during Vascularized Toe Proximal Interphalangeal Joint Transfer

BACKGROUND

Significant extension deficit is a common problem after a vascularized toe proximal interphalangeal joint transfer. One of the main causes related to extensor lag is central slip deficiency of the donor toes. In their clinical practice, the authors performed both the Stack and Te techniques to reconstruct central slip function during a joint transfer. The aim of this study was to compare the long-term outcomes of vascularized joint transfers between these two techniques.

METHODS

From May of 2009 to October of 2021, 38 digits in 36 patients (28 men and 8 women) underwent free vascularized toe joint transfer requiring central slip reconstruction. Eight and 30 digits were reconstructed with the Stack technique and the Te technique, respectively.

RESULTS

The median length of follow-up was 19 months (range, 5 to 78 months). The overall median extension lag was 20 ± 20 degrees and flexion was 80 ± 20 degrees. There were no significant differences in extension lag (25 ± 29 degrees versus 20 ± 15 degrees; P = 0.281), flexion (75 ± 10 degrees versus 85 ± 20 degrees; p = 0.13), or range of motion (53 ± 23 degrees versus 63 ± 15 degrees; P = 0.076) of the joints between the Stack and Te techniques after the transfers.

CONCLUSIONS

From the limited number of cases, both the Stack and Te techniques provided similar outcomes in correcting extension lag in vascularized joint transfers. The Te technique is a simplified and effective method for central slip reconstruction, whereas caution is advised when using the Stack technique because of potential complications.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Ulnar Superficialis Slip Resection Versus Radial Superficialis Slip Resection: A Biomechanical Pilot Study

BACKGROUND

There are numerous clinical scenarios during which the surgeon contemplates whether the radial or ulnar slip of the flexor digitorum superficialis (FDS) should be sacrificed. To date no study has assessed the point of failure of each one of the FDS slips in each digit, aiding the avid surgeon in deciding which slip to sacrifice.

METHODS

A total of 41 digits were assessed, each digit was dissected, and a specimen containing the denuded bone of the middle phalanx with the attachments of the ulnar and radial FDS slips was obtained. An Instron 4502 device was utilized to biomechanically assess the point of failure of each slip of each digit.

RESULTS

There was no statistical difference between ulnar and radial slip point of failure when compared across all digits and subjects. There was no statistical difference between male and female subject's specimens. The point of failure was higher in the ulnar slips of the second and third digits, whereas the point of failure was higher in the radial slips of the fourth and fifth digits.

CONCLUSIONS

Sacrifice of a FDS slip may cause loss of grip strength. In several clinical scenarios one may be faced with the dilemma which FDS slip to sacrifice. Our findings show this is not an arbitrary choice. Hand surgeons should keep our findings in mind when deciding which slip to sacrifice, in effort to preserve function and strength in the injured hand.

Reconstruction of the central slip insertion of the extensor tendon with the partial slip of the flexor digitorum superficialis tendon

INTRODUCTION

To introduce the surgical approach and clinical effect of transferring the partial slips of the flexor digitorum superficialis (FDS) tendon to reconstruct the insertion of the central slip of the extensor tendon (CSET) through an established bone tunnel (BT).

MATERIALS AND METHODS

From April 2019 to March 2021, nine patients (six males and three females) with the CSET insertion rupture or defect were admitted to the institution and the CSET insertion was reconstructed with partial tendon slips on both sides of the FDS. The active range of motion of the interphalangeal joint of the affected finger was measured by a goniometer, the degree of pain was evaluated by visual analogue scale (VAS), and the grip strength of the affected limb was measured by an electronic hand dynamometer.

RESULTS

The average postoperative follow-up was 12 months. No complications occurred. At the last follow-up, six of the patients were very satisfied and three were satisfied with their recovery.

CONCLUSION

The reconstruction of the CSET insertion by transferring the partial tendon slips of the FDS seem to be safe and feasible with minimal invasion to the donor tendon.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Central Slip Reconstruction With a Distally Based Flexor Digitorum Superficialis Slip: A Biomechanical Study

PURPOSE

The ideal method of central slip reconstruction is difficult to determine due to the multitude of techniques, nonstandardized outcome reporting, and small patient series in the literature. Although most boutonniere deformities may be treated with nonsurgical measures, chronic, subacute, or open injuries may require operative intervention. To aid surgeons in the choice of the ideal central slip reconstruction method, this biomechanical study compared the 3 most common methods performed at our institution: direct repair, lateral band centralization, and distally-based flexor digitorum superficialis (FDS) slip repair.

METHODS

A boutonniere deformity was induced in 35 fresh-frozen cadaver digits. The central slip was repaired in 9 digits using a primary suture repair, in 9 digits using a lateral band centralization technique, and in 9 digits using a distally-based FDS slip reconstruction. A control group without injury was tested in 8 digits. Following repair or reconstruction, each digit was tested for load to failure, strain, and stiffness at the repair.

RESULTS

The average load to failure after central slip reconstruction was significantly greater for a distally based FDS slip method at 82.1 ± 14.6 N (95% CI, 62.2-101.9 N) than all other repair types. Although the FDS slip reconstruction was not as strong as the intact state (82.1 N vs 156.2 N, respectively), it was 2.6 times stronger than the lateral band centralization (82.1 N vs 31.6 N, respectively) and 3 times stronger than a primary repair (82.1 N vs 27.6 N, respectively).

CONCLUSIONS

Reconstruction of the central slip using a distally-based FDS slip provided the greatest biomechanical strength compared with the direct repair or lateral band centralization.

CLINICAL RELEVANCE

The use of a distally based reconstruction using FDS may allow for safer early motion.

Spiral Oblique Retinacular Ligament Procedure Using Flexor Digitorum Profundus Hemi-Tendon Transfer: Anatomical Basis and Clinical Application

PURPOSE

The spiral oblique retinacular ligament (SORL) procedure acts as a dynamic tenodesis to restore distal interphalangeal joint (DIP) extension and restrain proximal interphalangeal hyperextension. Despite the ingenious technique based on the oblique retinacular ligament anatomy, obtaining strong internal fixation remains an issue during the SORL procedure. We present a modified technique using the flexor digitorum profundus (FDP) hemi-tendon transfer.

METHODS

We dissected 5 fresh cadaveric specimens to evaluate morphometric parameters of the SORL procedure using the hemi-FDP. The volar groove of the FDP tendon was identified in zone I of the flexor sheath and the tendon was divided into radial and ulnar bundles. The selected hemi-tendon was divided at the proximal edge of the A1 pulley and a SORL procedure was performed through a transosseous tunnel in the distal phalanx. This technique was used in 3 patients with swan neck deformity.

RESULTS

The optimal distance between the DIP joint and the anterior drill hole of the transosseous tunnel was 7.6 mm (range, 6.8-8.5 mm). The relative loss of length of the tendon owing to the SORL path was 25.8 mm (range, 19.6-29.9 mm). In the clinical cases, the procedure improved DIP joint extension lag and prevented proximal interphalangeal joint hyperextension. Preserving one-half of the FDP allowed complete flexion of the DIP joint.

CONCLUSIONS

The procedure is technically feasible. Its main advantages are that a distal suture is not required and that the substantial length of the tendon allows sturdy proximal internal fixation.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Flexor Digitorum Superficialis tendon transfer for a long-standing boutonniere deformity finger - a retrospective study of 11 cases

INTRODUCTION

A long-standing boutonniere deformity is challenging to treat because of well-established complex pathophysiological changes in the extensor expansion mechanism. The role of ulnar slip flexor digitorum superficialis tendon transfer for central slip reconstruction in such chronic deformities is analyzed and correlated with the functional outcome.

HYPOTHESIS

Ulnar slip FDS tendon corrects the long-standing boutonniere deformity and replicates anatomical repair.

METHODS

We conducted a retrospective study between 2014 and 2016 and operated on 11 patients by FDS tendon transfer to the extensor expansion's central slip. We compared the preoperative and postoperative range of movements in the proximal interphalangeal joint, distal interphalangeal joint, Visual analogue score, and grip strength. Also, we statistically correlated various parameters and non-parameters affecting the functional outcomes.

RESULTS

The mean time interval between the injury and surgery was 39 months. The average follow-up of our study was 15.4 months. Ten of the 11 patients had good functional outcomes with statistically significant improvement in the movements and grip strength (p<0.05).

CONCLUSIONS

Ulnar slip FDS tendon transfer is effective for central slip reconstruction in a long-standing boutonniere deformity. Minimal degrees of proximal interphalangeal joint extension deficit is inevitable due to the chronicity and adaptive changes in the ligament-tendon-bone complex.

LEVEL OF EVIDENCE

IV; retrospective case study.

Anatomic Repair of the Central Slip with Anchor Suture Augmentation for Treatment of Established Boutonniere Deformity

Backgroud

The rupture of the central slip of an extensor tendon of a finger causes a boutonniere (or buttonhole) deformity, characterized by pathologic flexion at the proximal interphalangeal (PIP) joint and hyperextension at the distal interphalangeal (DIP) joint. Currently, there are no standard treatment guidelines for this deformity. This study aimed to report clinical results of surgery to correct chronic boutonniere deformity.

Methods

This retrospective case series was conducted between January 2010 and December 2018 and only 13 patients with trauma-induced chronic deformity were included. After excision of elongated scar tissue, a direct anatomic end-to-end repair using a loop suture technique with supplemental suture anchor augmentation was conducted. Total active motion was assessed before and after surgery and self-satisfaction scores were collected from phone surveys.

Results

All patients presented with Burton stage I deformities defined as supple and passively correctable joints. The initial mean extension lag of the PIP joint (43.5°) was improved by an average of 21.9° at the final follow-up (p < 0.001). The mean hyperextension of the DIP joint averaged 19.2° and improved by 0.8° flexion contracture (p < 0.001). The average total active motion was 220.4° (range, 160°–260°). Based on the Souter's criteria, 69.2% (9/13) of the patients had good results. Only 1 patient reported fair outcome and 23.1% (3/13) reported poor outcome. The average Strickland formula score was 70 (range, 28.6–97.1). In total, 10 patients (77%) had excellent or good results. Of 10 patients contacted by phone, self-reported satisfaction score was very satisfied in 2, satisfied in 3, average in 3, poor in 1, and very poor in 1. Three patients reported a relapse of the deformity during range of motion exercises, 1 of whom underwent revision surgery. One patient complained of PIP joint flexion limitation, and 2 complained of DIP joint flexion limitation at final follow-up.

Conclusions

In chronic boutonniere deformity, central slip reconstruction with anchor suture augmentation can be an easily applicable surgical option, which offers fair to excellent outcome in 77% of the cases. The risk of residual extension lag and recurrence of deformity should be discussed prior to surgery.

[Extensor tendon injuries at the level of the proximal interphalangeal joint]

Closed and open injuries of the extensor mechanism at the proximal interphalangeal (PIP) joint can involve the central slip, the lateral slips or both. They are classified as zone III injuries. All open injuries on the dorsal side of the PIP joint should raise suspicion of an extensor tendon injury that is frequently overlooked. The operative strategy consists of wound revision with extensor tendon suture or refixation of the central slip. Acute closed central slip injuries are clinically diagnosed (Elson test) after ruling out bony injuries to the joint. Nondisplaced avulsions of the central slip insertion or lacerations can be treated nonoperatively by splinting. For displaced avulsions and complex injuries the treatment is surgical. In overlooked injuries a typical deformity (buttonhole/Boutonnière deformity) develops within 1-2 weeks that is characterized by an extension lag of the PIP joint and hyperextension at the distal interphalangeal joint. In early cases, when passive extension is still complete (mobile buttonhole deformity) the central slip can be immediately reconstructed. In fixed deformities complete passive extension of the PIP joint has to be restored before surgery by hand therapeutic measures or PIP joint release. Depending on the pattern of the injury and the resulting defects, a number of reconstructive techniques have been established that are summarized in this article. The functional results can be limited by tendon adhesions, imbalance within the reconstructed extensor apparatus and stiff joints that can all restrict the range of motion. Therefore, active rehabilitation protocols are mandatory for optimal results.

Treatment of the fresh central slip avulsion of the extensor tendon by bone tunnel-tendon suture: a prospective cohort study

BACKGROUND

The current evidence base for the management of central slip avulsions is limited from obtaining a best approach. The purpose of this study was to evaluate the clinical effect and feasibility of repairing the fresh central slip avulsion by bone tunnel-tendon suture.

METHODS

Twenty-four cases of open and closed central slip avulsions were prospectively studied. They were treated by suturing the tendon to the pre-holed bone through two parallel bone tunnels. Follow-up was conducted at 1 month, 3 months, 6 months, 12 months and 18 months after the operation. Symptoms, degree of satisfaction with the appearance, complications, Crawford's evaluation, DASH scores and the total active movement (TAM) were collected.

RESULTS

The follow-up period was 6~18 months (mean 13 months). Finger function was assessed using the Crawford's evaluation criteria: excellent in 12, good in 10, average in 2, with an excellent and good rate of 91.7%. DASH scores ranged from 37 to 47(mean 39). According to the Chinese Medical Association's trial criteria for assessing the function of upper limbs, excellent, good and average cases were 9, 14 and 1 respectively. The range of motion gradually improved over time. Conclusions Good prognosis can be achieved through bone tunnel-tendon suture for the treatment of fresh central slip avulsion.

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

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

Management of Acute Extensor Tendon Injuries

Thin soft tissue covering extensor tendons make them prone to injury. The extensor mechanism achieves a delicate balance with the flexor system. Inappropriate management in the acute setting can lead to long-term deformity and dysfunction. Acute extensor tendon injuries are usually managed with splinting and/or primary repair of the tendon. In cases of tendon length loss, tendon graft or flap may be necessary for reconstruction. This article presents a series of cases illustrating the appropriate management of traumatic extensor tendon injuries.

Reconstruction of Traumatic Central Slip Injuries: Technique Using a Slip of Flexor Digitorum Superficialis

Multiple reconstruction techniques have been described for correction of boutonniere deformities including direct repair, central slip reconstruction, lateral band reconstruction, transverse retinacular ligament reconstruction, staged reconstruction, and extensor tenotomy. Each technique has been reported to have variable results with complications including capsular contracture, loss of proximal interphalangeal flexion, and residual deformity. We describe a surgical technique for central slip reconstruction using a slip of the flexor digitorum superficialis tendon through a bone tunnel.

Technique of Dynamic Flexor Digitorum Superficialis Transfer to Lateral Bands for Proximal Interphalangeal Joint Deformity Correction in Severe Dupuytren Disease

Pseudo-boutonniere deformity is an uncommon complication from long-standing proximal interphalangeal (PIP) joint contracture in Dupuytren disease. Prolonged flexion contracture of the PIP joint can lead to central slip attenuation and resultant imbalances in the extensor mechanism. We present a technique of flexor digitorum superficialis (FDS) tendon transfer to the lateral bands to correct pseudo-boutonniere deformity at the time of palmar fasciectomy for the treatment of Dupuytren disease. The FDS tendon is transferred from volar to dorsal through the lumbrical canal and sutured into the dorsally mobilized lateral bands. This technique presents an approach to the repair of pseudo-boutonniere deformity in Dupuytren disease.

Sagittal band, boutonniere, and pulley injuries in the athlete

PURPOSE OF REVIEW

While hand injuries occur frequently in the athletic population, sagittal band ruptures, boutonniere deformities, and pulley ruptures are infrequently encountered. These injuries represent diagnostic challenges and can result in significant impairment. Early recognition with appropriate treatment is necessary to maximize recovery and minimize return to athletic competition. This review will focus on the underlying mechanism, pathophysiology of injury, diagnosis, and treatment of each of these injuries.

RECENT FINDINGS

With respect to sagittal band ruptures, boutonniere deformities, and pulley ruptures, the recent literature has been limited in scope. For sagittal band injuries, current efforts have focused on alternative techniques for sagittal band reconstruction. Little progress has been made in recent years with respect to boutonniere injuries in the athletic population; prevention of fixed deformities remains the backbone of treatment. The exact contribution from individual and combined pulley injuries in the creation of bowstringing remains controversial. Recent anatomical studies have failed to definitively answer the question of what degree of rupture is necessary to create symptomatic bowstringing. Favorable outcomes, with respect to both preventing bowstringing and returning to full athletic participation, have been newly reported following pulley reconstruction in rock climbers. Due to the infrequent nature of sagittal band ruptures, boutonniere deformities, and pulley ruptures, current treatment is mostly guided by historically established methods, limited case series, and case reports. Nonsurgical treatment remains the mainstay for most injuries and, if employed early, often precludes the need for surgery. Further anatomical and clinical research, including outcome studies, is necessary in guiding treatment algorithms.

Collateral Ligament Reconstruction of the Proximal Interphalangeal Joint

Proximal interphalangeal joint collateral ligament injuries are common; however, chronic instability of this joint is rare. In such cases, however, there is no consensus on optimal management. Various repairs and reconstructions have been devised, although the literature on outcomes remains scant. We present a method of reconstruction of the proximal interphalangeal joint collateral ligament using a distally based slip of the flexor digitorum superficialis tendon.

Two-staged extensor tendon reconstruction for zone 6 extensor tendon loss of the fingers: indications, technique and results

Over a 20-year period, six patients (19 tendons) underwent two-staged extensor tendon reconstruction using silicone rods followed by palmaris longus tendon grafts sutured proximally to the divided flexor carpi radialis tendon. All patients were young men (mean age, 22 years) who sustained the injury in car accidents. The soft tissue loss from the dorsum of the hand was associated with extensor tendon loss over the entire zone 6 with or without loss in zone 7. Primary soft tissue coverage was done elsewhere, and patients presented for secondary tendon reconstruction. All patients had supple metacarpophalangeal joints before reconstruction. After the two-staged tendon reconstruction, full or near-full active flexion at the metacarpophalangeal joints was obtained in all patients. However, minor extension lags (10°-15°) at the metacarpophalangeal joints were seen in 15 out of 19 reconstructed fingers.

Open extensor tendon injuries

The extensor tendons in the dorsum of the hand lie relatively superficially, making open injuries to the extensor mechanism a common source of morbidity. These injuries can range from simple clean lacerations to complex open injuries associated with severe skin and soft tissue loss. Although many advances in the treatment of tendon injuries focused on the flexor tendon, the extensor tendon has begun to receive more attention in recent literature. Knowledge of modern repair techniques and rehabilitation protocols may improve patient outcomes. This Current Concepts article summarizes the treatment of open extensor tendon injuries with a focus on the recent literature.

Extensor tendon injuries in athletes

Extensor tendon injuries of the hand and wrist in high-level athletes can cause a delay in return to play and permanently affect their performance. Given the inherent demand for a speedy and complete recovery, orthopedic surgeons must have an understanding of how to best direct an athlete's treatment for these injuries. The extensor anatomy is very intricate and a thorough understanding of the anatomy can help with both diagnosis and treatment. However, untreated or poorly managed injuries are at risk of leading to chronic deformities. We will discuss the diagnosis and management of the most common extensor tendon injuries and tendinopathies of the hand found in athletes: mallet fingers, swan-neck deformities, boutonniere deformities, central slip ruptures, sagittal band ruptures, intersection syndrome, extensor carpi ulnaris tendinitis, and extensor carpi ulnaris subluxation.

Closed soft tissue extensor mechanism injuries (mallet, boutonniere, and sagittal band)

The extensor mechanism of the hand is complex and can be disrupted at several different points, from hand trauma. This article summarizes current concepts relating to the presentation and treatment of closed soft tissue injuries of the extensor mechanism in zones I, III, and V, commonly known as mallet finger and boutonniere deformities and sagittal band injuries.

Simultaneous reconstruction of extensor mechanism in the free transfer of vascularized proximal interphalangeal joint

From a recent systemic review, vascularized toe proximal interphalangeal joint (PIPJ) transfer achieved an average arc of motion (AOM) of merely 37 degrees for finger PIPJ reconstruction. Despite the technical refinement over the past 3 decades, the resulting active motion of the reconstructed joint remains unpredictable and often fraught with extension lag. The technique for vascularized toe PIPJ transfer at our institute has evolved over the years to its current state, with simultaneous extensor mechanism reconstruction being a major component. During the transfer, the quality of extensor tendons on the recipient finger and donor toe are carefully evaluated. If the central slip of finger extensor is destroyed but the quality of lateral bands is adequate, centralization of lateral bands overlying the transferred PIPJ is performed. If there is acceptable central slip remnant at the proximal phalanx level, modified Stack procedure is performed for central slip reconstruction while leaving the lateral bands in continuity. If both lateral bands are poor, modified Stack procedure is performed unless the central tendon of the toe is strong enough to extend the PIPJ. From November 2008 to October 2010, 7 joints were transferred with this modified technique. The average follow-up was 18.2 months. The average active AOM of the transferred PIPJ was 56.4 degrees. The average extension lag of the toe PIPJ was 10.7 and 16.4 degrees before and after the transfer, respectively. Simultaneous reconstruction of extensor mechanism decreases the extension lag without sacrificing AOM of the transferred PIPJ.

Extensor tendon injuries

The extensor mechanism of the fingers, hand, wrist, and forearm is extremely intricate. Disruptions to the extensor system are common and can be associated with poor patient outcomes when not treated appropriately. Although extensor tendon injuries receive much less attention in the literature than flexor tendon injuries do, several recent studies have examined this topic. This article presents an overview of the treatment of extensor tendon injuries, with a focus on recent developments.