Flexor Digitorum Profundus Repair Research Articles

Outcomes at 3 Months of a Place and Active Hold Method of Flexor Tendon Rehabilitation Following Zone II Injury.

Background: Previous studies have shown that outcomes following a place and active hold (PAH) are better than a passive flexion protocol after a two-strand core-suture repair of flexor tendons injuries in zone II. This study aims to determine the outcomes of a PAH protocol of flexor tendon rehabilitation following a four-strand core-suture plus an epitendinous suture repair of the flexor digitorum profundus (FDP) combined with a simple horizontal loop repair of the flexor digitorum superficialis (FDS). Methods: This is a prospective study of patients with complete injury to both flexor tendons in zone II. All tendons were repaired with a simple horizontal loop for FDS and four-strand core-suture plus epitendinous suture for FDP. The PAH protocol was used postoperatively for 6 weeks. The outcome was evaluated using flexion contracture and total active motion (TAM), interpreted using Strickland criteria and categorised as excellent, good, fair and poor at 6 weeks and 3 months. The linear regression model was used to determine predictors of outcomes. Results: The study included 32 patients with flexor tendon injury in 46 fingers. No repairs ruptured, and 24 (52%) digits achieved good or excellent motion 6 weeks after surgery using the Strickland criteria. According to the Strickland criteria, 41 (89%) digits ranked as excellent and good with no poor result at a 3-month follow-up. Four patients had 5-10° of flexion contracture. Age was the predictor of TAM at 6 weeks and accounted for 13% of its variation. Improvement of TAM from 6 weeks to 3 months was related to age and flexion contracture at 6 weeks. Conclusions: The PAH protocol can be considered a safe technique for flexor rehabilitation after four-strand core-suture repair of FDP in zone II. Level of Evidence: Level IV (Therapeutic).

A Comparison of Outcomes at Twelve Weeks of Traditional Button-Over-Nail versus Bone Anchor Repair of Zone I Flexor Digitorum Profundus Tendon Injury.

Background: The repair of zone 1 flexor tendon injury often relies on re-inserting the flexor digitorum profundus (FDP) tendon to the distal phalanx. The aim of this retrospective study is to compare outcomes at 12 weeks following traditional button-over-nail (BON) versus bone anchor (BA) repair of zone I FDP injury. Methods: Patients undergoing zone 1 FDP repair between April 2007 and September 2018 using a BON or a BA were included in the study. Patient demographics, complications, arc of flexion of distal (distal interphalangeal joint [DIPJ]) and proximal interphalangeal joint (PIPJ) and patient-rated outcomes were analysed. Results: Forty-three patients were included in the study: 21 in the BA group and 22 in the BON group. Good function was achieved by 20 patients in BA versus nine in BON. Complications occurred in five BA patients versus 10 BON patients. Patients achieved a mean active DIPJ flexion of 49° and 31° and PIPJ flexion of 92° and 57° in the BA and BON groups, respectively. Conclusion: Our study demonstrates better arc of motion, patient-rated outcomes and lower complications at 12 weeks after surgery in patients undergoing zone 1 FDP repair using a BA. Level of Evidence: Level III (Therapeutic).

Does Digital Nerve Injury Affect Range of Motion Recovery After Zone 2 Flexor Tendon Repair?

Evidence surrounding the impact of concomitant digital nerve injury on the outcome of zone 2 flexor tendon repair is sparse and conflicting. The purpose of this study is to assess the impact of digital nerve injury on the range of motion recovery after zone 2 flexor tendon repair. We hypothesized that digital nerve injury is independently associated with decreased motion after zone 2 flexor digitorum profundus (FDP) repair. This is a single-institution, multisurgeon retrospective analysis of patients treated with primary zone 2 FDP repair. Patients with or without digital nerve injuries were included. Patients with fracture, extensor tendon injury, dysvascularity, follow-up duration of less than 10 weeks, and younger than 15 years were excluded. The primary outcome measure was Strickland percentage at the last therapy visit. Bivariate analysis was performed using simple linear regression. These results were used to guide backward stepwise multivariable analysis of qualifying exploratory variables. Forty-one patients with a total of 54 zone 2 FDP injuries qualified. Mean follow-up duration was 24 ± 10 weeks, and mean age was 38 ± 18 years. Thirty-three digits had a concomitant digital nerve injury, 26 digits had multidigit involvement, and 42 digits had combined FDP and flexor digitorum superficialis (FDS) injuries. Both older age and concomitant FDS injury exhibited independent relationships with poorer range of motion outcomes (P < .05). Digital nerve injury, follow-up duration, gender, and multidigit involvement did not influence final digital motion. In patients undergoing zone 2 FDP repair, concomitant digital nerve injury is not independently associated with poorer postoperative active range of motion.

Beyond the Core Suture: A New Approach to Tendon Repair.

Background:Despite significant improvements in zone II flexor tendon repair over the last 2 decades, function-limiting complications persist. This article describes 2 novel repair techniques utilizing flexor digitorum superficialis (FDS) autografts to buttress the flexor digitorum profundus (FDP) repair site without the use of core sutures. The hypothesis being that the reclaimed FDS tendon autograft will redistribute tensile forces away from the FDP repair site, increasing overall strength and resistance to gapping in Zone II flexor tendon injuries compared with the current clinical techniques.Methods:Two novel FDP repair methods utilizing portions of FDS have been described: (1) asymmetric repair (AR), and (2) circumferential repair. Ultimate tensile strength and cyclical testing were used to compare novel techniques to current clinical standard repairs: 2-strand (2-St), 4-strand (4-St), and 6-strand (6-St) methods. All repairs were performed in cadaveric sheep tendons (n = 10/group), by a single surgeon.Results:AR and circumferential repair techniques demonstrated comparable ultimate tensile strength to 6-St repairs, with all 3 of these techniques able to tolerate significantly stronger loads than the 2-St and 4-St repairs (P < 0.0001). Cyclical testing demonstrated that AR and circumferential repair were able to withstand a significantly higher total cumulative force (P < 0.001 and P = 0.0064, respectively) than the 6-St, while only AR tolerated a significantly greater force to 2-mm gap formation (P = 0.042) than the 6-St repair.Conclusion:Incorporating FDS as an autologous graft for FDP repair provides at least a comparable ultimate tensile strength and a significantly greater cumulative force to failure and 2-mm gap formation than a traditional 6-St repair.

Flexor digitorum profundus with or without flexor digitorum superficialis tendon repair in acute Zone 2B injuries.

A total of 53 patients with complete cuts of two flexor tendons in Zone 2B treated over a 9-year period was reviewed. Twenty-three patients (28 fingers) had only flexor digitorum profundus repair, while 30 patients (36 fingers) had both flexor digitorum profundus and flexor digitorum superficialis repairs, with a mean follow-up of 21 months (range 12-84). The decision to repair the flexor digitorum superficialis was made according to intraoperative judgement of ease of repair and gliding of the flexor digitorum profundus tendon. Two groups of patients showed no significant differences in total range of active or passive digital motion and power grip percentage to the contralateral hand. However, the values of power grip were statistically superior in the patients with both tendons repaired. The patients after flexor digitorum profundus-only repairs showed significantly greater but still mild flexion contracture (mean 20 °) of the operated digits. The Tang gradings were the same with 89% good and excellent rates in both groups. The conclusion is that although repair of both flexor digitorum profundus and flexor digitorum superficialis tendons is slightly more preferable based on increased grip strength, the repair of the flexor digitorum superficialis together with flexor digitorum profundus is not mandatory. Whether or not to repair flexor digitorum superficialis is an intraoperative decision based on the ease of gliding of the repaired tendon(s).Level of evidence: III.

Zone 2 Flexor Tendon Repair Location and Risk of Catching on the A2 Pulley

To determine the region of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons in zone 2 that, when involved by a laceration repair, will reliably catch on the A2 pulley after surgery. Using fresh-frozen cadavers (5 hands, 20 digits), excursions of the FDP and FDS tendons were measured in relation to the A2 pulley. The C1, A3, and C2 pulleys were resected. The digit was maximally flexed by applying traction to the flexor tendon in the forearm. An 8-0 suture tag was placed in the flexor tendons immediately distal to the A2 pulley. The digit was then passively fully extended to measure tendon excursion. Measurements were repeated with 50% venting and 100% release of the A4 pulley. Reference points such as tendon insertions and flexion creases were obtained. This protocol was repeated sequentially for the index, middle, ring, and little fingers. For all 20 fingers, the suture placed into the FDP just distal to the A2 pulley with the finger fully flexed traveled 1.6 ± 1.9 mm distal to the proximal edge of the A4 pulley with passive extension of the finger. The mean excursion for the FDP was 24.6 ± 3.2 mm, and 16.9 ± 3.1 mm for the FDS. The mean A2 pulley length was 16.2 ± 3.5 mm, and the mean distance between the distal edge of the A2 pulley and the proximal edge of the A4 pulley was 23.0 ± 3.3 mm. Venting the A4 pulley 50% and 100% increased FDP excursion a maximum of 0.9 and 1.9 mm, respectively. An FDP repair proximal to the A4 pulley will slide under the A2 pulley with full active digital flexion after surgery. If the distal FDP stump lies underneath the A4 pulley with the digit fully extended, the FDP repair will not likely engage the A2 pulley with full flexion after surgery. The FDP excursion can be reliably predicted as a percentage of the A2 (distal) to the A4 (distal) pulley distance. Most importantly, the distance between the repair site and the A4 pulley approximately equals the length of the A2 pulley that requires release to avoid postoperative triggering. Knowledge of this high-risk region of flexor tendon repair will guide surgeons regarding the potential need for partial release of the A2 pulley.

Use of a relative motion flexion orthosis for postoperative management of zone I/II flexor digitorum profundus repair: A retrospective consecutive case series

Study DesignA retrospective, single-center, consecutive case series. IntroductionIn concept, a relative motion flexion (RMF) orthosis will induce a “quadriga effect” on a given flexor digitorum profundus (FDP) tendon, limiting its excursion and force of flexion while still permitting a wide range of finger motion. This effect can be exploited in the rehabilitation of zone I and II FDP repairs. Purpose of the StudyTo describe the use of RMF orthoses to manage zone I and II FDP 4-strand repairs. MethodsMedical record review of 10 consecutive zone I and II FDP tendon repairs managed with RMF orthosis for 8 to 10 weeks in combination with a static dorsal blocking or wrist orthosis for the initial 3 weeks. ResultsIndications included sharp lacerations (n = 6), ragged lacerations (n = 2), staged flexor tendon reconstruction (n = 1), and type IV avulsion (n = 1). In 8 of the 10 cases that completed follow-up, the mean arc of proximal interphalangeal/distal interphalangeal active motion were as follows: sharp, 0° to 106°/0° to 75°; ragged, 0° to 90°/0° to 25°; reconstruction, 0° to 90°/10° to 45°; and avulsion, 0° to 95°/0° to 20°. Grip performance available for 6 of 10 cases was 62% to 108% of the dominant hand. There were no tendon ruptures, secondary surgeries, or proximal interphalangeal joint contractures. ConclusionBased on this small series, the RMF approach appears to be safe and effective. It can lead to similar mobility and functional recovery as other early active motion protocols, with certain practical advantages and without major complications. Further investigation with larger, multicenter, prospective, longitudinal cohorts and/or randomized clinical trials is necessary.

Results of Flexor Digitorum Profundus Repair Alone in Rupture of Both Flexor Tendons in Zone II: A Case Series

Background: Flexor tendon damagemakes up a small number of total hand injuries; butmanagement of these injuries often poses a surgical challenge because the results remain unpredictable despite all efforts. The results of flexor tendon repair damage of both deep and superficial injuries, especially in zone II, despite using various methods, still remains poor. Objectives: This study aimed to assess results of flexor digitorum profundus (FDP) repair with resection of flexor digitorum superficialis (FDS) stump in a setting where both tendons are transected. Lack of human studies for FDP repair alone makes the decision difficult. Methods: Files of patients, who were referred to the research hospitals with flexor tendon rupture between April 2014 and April 2016 were studied. Patients, who had recent concurrent FDP and FDS rupture in zone II were included. After six months, range of motion (ROM), pinch strength, and disabilities of the arm, shoulder and hand (DASH) score were measured. Results: Twenty patients were studied; three were excluded due to missing follow-ups. Seventeen patients remained in the study. Thirteen were males and four were females. Ages were between 17 and 55, with mean age of 23.7 years old. According to the DASH score, 13 patients were placed in mild disability group (score one to seven) and four patients showed no disability (score zero). Conclusions: The results suggest the outcomes of FDP repair alone in zone II is comparable to repairing both tendons.

Prognostic factors for digital range of motion after intrasynovial flexor tendon injury and repair: Long-term follow-up on 273 patients treated with active extension-passive flexion with rubber bands

Study DesignObservational cohort study. IntroductionInvestigating prognostic factors using population-based data may be used to improve functional outcome after flexor tendon injury and repair. Purpose of the StudyThe aim of this study is to investigate the effect of concomitant nerve transection, combined flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendon transection and the age of the patient, on digital range of motion (ROM) more than 1 year after FDP tendon transection and repair in zone I and II. MethodsTwo hundred seventy-three patients with a total of 311 fingers admitted for FDP injury in zone I and II were treated with active extension-passive flexion with rubber bands and followed for at least 1 year. We compared outcome by evaluating digital mobility using Strickland's evaluation system. ResultsAt 12 months 72% of patients aged > 50 had fair or poor ROM compared to 17% of patients aged 0-25 years. At 24 months the results for patients aged > 50 had improved to 33% with fair or poor ROM, whereas no improvement had occurred for patients aged 0-25 (17% with fair or poor ROM). Concomitant nerve transection and FDS tendon transection had no negative effects on digital mobility. DiscussionAge above 50 was significantly associated with impaired digital ROM during the first year after flexor tendon injury and repair but not at 2 years follow-up. Concomitant nerve transection and combined transection of FDP and FDS do not affect digital mobility. ConclusionsOlder patients are likely to have a slower healing process and impaired digital ROM during the first year after surgery.

Sonographic study of repair, gapping and tendon bowstringing after primary flexor digitorum profundus repair in zone 2.

III.

A Mechanical Evaluation of Zone II Flexor Tendon Repair Using a Knotless Barbed Suture Versus a Traditional Braided Suture

To determine repair site bulk, gliding resistance, work of flexion, and 1-mm gap formation force in zone II flexor tendon lacerations repaired with knotless barbed or traditional braided suture. Transverse zone II lacerations of the flexor digitorum profundus (FDP) tendon were created in 36 digits from 6 matched human cadaveric pairs. Repair was performed with 2-0 barbed suture (n = 18) or 3-0 polyethylene braided suture (n = 18). Pre- and postrepair cross-sectional area was measured followed by quantification of gliding resistance and work of flexion during cyclic flexion-extension loading at 10 mm/min. Thereafter, the repaired tendons were loaded to failure. The force at 1 mm of gap formation was recorded. Repaired FDP tendon cross-sectional area increased significantly from intact, with no difference noted between suture types. Gliding resistance and work of flexion were significantly higher for both suture repairs; however, we identified no significant differences in either nondestructive biomechanical parameters between repair types. Average 1-mm gap formation force with the knotless barbed suture (52 N) was greater than that of the traditional braided suture (43 N). We identified no significant advantage in using knotless barbed suture for zone II FDP repair in our primary, nondestructive mechanical outcomes in this in vitro study. In vivo studies may be warranted to determine if one suture method has an advantage with respect to the parameters tested at 4, 6, and 12 plus weeks postrepair and the degree of adhesion formation. The combined laboratory and clinical data, in additional to cost considerations, may better define the role of barbed knotless suture for zone II flexor tendon repair.

Flexor Digitorum Superficialis Repair Outside the A2 Pulley After Zone II Laceration: Gliding and Bowstringing

To evaluate the changes in maximum flexion angle, gliding coefficient, and bowstringing after a combined repair of both flexor tendons with the flexor digitorum superficialis (FDS) rerouted outside the A2 pulley in cadaveric hands. We performed 4 different repairs on cadaveric hands, with each repair tested on 9 unique digits. In total, 12 cadaveric hands and 36 digits were used. The thumb and little finger were removed from each hand and excluded from testing. Group 1 was sham surgery. Group 2 combined flexor digitorum profundus (FDP) and FDS laceration and repair with both slips of the FDS repaired inside the A2 pulley. Group 3 was FDP repair with one slip of the FDS repaired inside A2 and the other slip left unrepaired. Group 4 was FDP repair with both slips of the FDS rerouted and repaired outside the A2 pulley. Maximum flexion angle, gliding coefficient, and bowstringing were measured in simulated active digital motion for each group. Rerouting and repairing the FDS outside the A2 pulley (group 4) significantly lowered gliding coefficient compared with repairs with both slips inside A2, with values similar to sham surgery. We observed no significant differences in maximum flexion angle among the 4 groups. Increased bowstringing was observed with both slips of the FDS repaired and rerouted outside the A2 pulley. In this cadaveric model, repair of both slips of the FDS outside the A2 pulley improved the gliding coefficient relative to repair within the A2 pulley, which suggests decreased resistance to finger flexion. Repair of the FDS outside the A2 pulley led to a slight increase in bowstringing of the FDS tendon. We describe a technique for managing combined laceration of the FDP and FDS tendons that improves gliding function and merits consideration.

Flexor Tendon–to–Volar Plate Repair: An Experimental Study and 3 Case Reports

To investigate the histology and tensile strength of flexor tendon-to-volar plate repair in a sheep model and to evaluate outcomes in 3 clinical cases. The flexor digitorum profundus (FDP) tendon of the hind limb of the sheep was cut at the ankle. The proximal end of the FDP tendon was then repaired to a distally based flap of the underlying volar plate after 2 cm of the distal FDP tendon were excised such that the distal FDP tendon was not directly in contact with the repair site. The repair was studied histologically and tested biomechanically at 8 intervals (0, 1, 2, 3, 4, 5, 6, 8, and 12 wk) following repair. Three clinical cases with flexor tendon-to-volar plate repair are presented. In all cases, the circumstances of the injury precluded the usual tendon-to-tendon repair. The first patient had a laceration of FDP in zone 1A and the other 2 patients had delayed 2-stage flexor tendon reconstruction. The mean breaking strength of the tendon-to-volar plate repair was 26 N at 0 week, 62 N at 1 week, 52 N at 2 weeks, and then progressively increased to reach 312 N at 12 weeks. Histologically, thin randomly arranged collagen fibers were seen at the repair site at 3 weeks; and healing with thick parallel collagen bundles were seen at 6 weeks. Clinically, the flexor tendon-to-volar plate repairs healed without rupture. All patients obtained full active range of motion at the metacarpophalangeal and proximal interphalangeal joints. The active range of motion at the distal interphalangeal joint was 0° to 50° in 2 patients and 0° to 40° in the third patient. The flexor tendon can heal to the volar plate in the sheep model. Suture of tendon to volar plate is an option in distal zone 1 FDP repair and FDP tendon reconstruction.

Prise en charge des lésions du tendon fléchisseur profond des doigts en zone 1

Flexor tendons repair in zone 1 is classically considered providing good results with an overall satisfactory finger function. However, the objective functional results after surgical repair of flexor digitorum profundus are sometimes disappointing. The authors describe the different surgical repair techniques available to the operator from so-called “traditional” sutures to newer methods of internal fixation using miniaturized anchor sutures. The management of postoperative procedures, that of failures and old cases are reported.

Zone II Flexor Tendon Repair in a 13-Month-Old: Report of a Complication

Despite early cautions against the primary repair of zone II flexor tendon injuries, recent advances in surgical technique and suture materials have allowed such repairs to become commonplace. The 6-strand repair technique is rarely applied to the young pediatric population, however, to our knowledge, no English-language articles have described this method of primary repair in zone II of children less than 2 years old. A 13-month-old male presented flexor digitorum profundus repair after lacerating it in zone II on a sharp aluminum can. The tendon was repaired with a 6-strand technique, using a 4.0 Fiberloop for the core suture and 6.0 Prolene for the epitendinous suture. Approximately four months after surgery, the patient developed a palmar collection at the level of his middle phalanx and a serosanguinous sinus tract at the distal interphalangeal crease. During the revision surgery, the inspection of the repaired tendon revealed a small gap filled with scar tissue. There was no evidence of new fistula formation at his final visit one month after the second procedure. After the revision, the patient could move his digit with minimal loss of range of motion at the distal interphalangeal joints. Unfortunately, he was subsequently lost to follow up. This surgical technique was selected to provide a strong repair that would allow the early postoperative movement. In retrospect, a 6-strand repair with braided suture is not ideal in young children as the bulky suture can cause a foreign-body reaction and possibly extrude through the skin. Additionally, the immobilization with a long-arm cast remains a valuable tool after tendon repair in infants who cannot voluntarily restrict their movements.

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

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. 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. 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 1.9mm at maximum flexion for group 3 specimens relative to group 1 controls. 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 1.9mm 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).

The Simple Transverse Intraosseous Phalangeal Suture for Zone 1 Flexor Digitorum Profundus Injuries

Zone 1 flexor digitorum profundus injury often precludes the use of a simple core suture as a result of a distal remnant that is too short. The aim of this study was to assess the senior author's (S.I.) simple technique for reinsertion of the flexor digitorum profundus tendon. The case series consisted of 12 patients who required a primary flexor digitorum profundus repair in zone 1, with all repairs performed by the senior author. A Bruner incision was extended to the pulp to expose the base of the distal phalanx. A two-strand repair was anchored to the distal phalanx using the author's technique, which involved passing a 3-0 polypropylene suture on a straight needle through a hypodermic needle that had been drilled through the base of the distal phalanx. This provided a stable, intraosseous, internal repair, allowing a standard early active mobilization regimen. Two patients had excellent results and 10 had good results in terms of distal interphalangeal joint range of movement (mean, 57 degrees; range, 51 to 80 degrees) and Quick Disabilities of the Arm, Shoulder and Hand questionnaire scores (mean, 12; range, 0 to 31.8). There were no reported tendon ruptures at the time of writing this article (range, 6 to 37 months after surgery). The authors present a technique for the repair of zone 1 flexor digitorum profundus injuries that is simple, can be performed quickly, is easily learned, and has results that compare favorably with other techniques in the literature. Furthermore, there is limited morbidity to surrounding fingertip structures. Therapeutic, IV.

The Effects of Oblique or Transverse Partial Excision of the A2 Pulley on Gliding Resistance During Cyclic Motion Following Zone II Flexor Digitorum Profundus Repair in a Cadaveric Model

The Effects of Oblique or Transverse Partial Excision of the A2 Pulley on Gliding Resistance During Cyclic Motion Following Zone II Flexor Digitorum Profundus Repair in a Cadaveric Model

The Effects of Oblique or Transverse Partial Excision of the A2 Pulley on Gliding Resistance During Cyclic Motion Following Zone II Flexor Digitorum Profundus Repair in a Cadaveric Model

To compare the gliding resistance of flexor tendons after oblique versus transverse partial excision of the A2 pulley in a human cadaveric model, to determine the effect of the angle of pulley trimming. We obtained 36 human flexor digitorum profundus tendons from the index through the little finger and repaired them with a modified Massachusetts General Hospital suture using 4-0 FiberWire. We repaired all tendons with a similar epitendinous stitch. We randomly assigned the tendons to 1 of 3 groups: intact pulley, transverse partial excision, or oblique partial excision. We measured peak and normalized peak gliding resistance between the repairs and the A2 pulley during 1,000 cycles of simulated motion. There was no significant difference in the peak or normalized peak gliding resistance at any cycle among the 3 groups. Both transverse and oblique trimming of the A2 pulley had similar effects on the peak and normalized gliding resistance after flexor tendon repair. When partial pulley resection is needed after flexor tendon repair, the transverse or oblique trimming of pulley edge does not affect repaired tendon gliding resistance.

The Use of Ultrasound in Evaluating Flexor Tendons following Surgical Repair

Sir:FigureZone 1 and 2 flexor tendon repairs are associated with difficult repairs and poor outcomes. Clinical scores cannot differentiate between repair rupture and tendon adhesions in a poorly scoring digit. Ultrasound is not used routinely postoperatively but is used when concern regarding the integrity of the repair exists. High-resolution transducers can be used to assess repair integrity, tendon excursion, and adhesions.1,2 This study aimed to assess whether ultrasound can accurately evaluate zone 1 and 2 flexor tendon repairs and whether imaging provided useful clinical information. A series of patients attended postoperatively for ultrasound of their injured digit. Inclusion criteria were zone 1 and 2 complete flexor tendon lacerations. Concomitant neurovascular injuries were included, but patients with additional injuries were excluded. Patients underwent tendon repair with a four-strand core tendon repair using a 3-0 polypropylene suture and a 6-0 polypropylene epitendinous suture. Subjects were splinted dorsally for 6 weeks, and early active mobilization was commenced. Between postoperative weeks 6 and 8, the injured digit(s) and the uninjured contralateral digit were scanned. High-frequency (12-MHz) linear array ultrasound including color flow Doppler was performed at rest and during active flexion and extension. For each tendon repair site, repair integrity, tendon thickness, tendon glide, presence of adhesions, and vascularity were recorded. Corresponding values were obtained from the contralateral uninjured digit. Tendon glide was graded as unimpaired or mildly, moderately, or severely impaired. Vascularity was noted as equal, increased, or decreased compared with normal. A Strickland score was calculated for each injured digit.3 Paired samples t tests were carried out. A value of p ≤ 0.05 was considered significant. Ultrasonic data of the tendon repair were compared with the scanned uninjured tendon and the Strickland score. Fifteen patients participated with a total of 17 injured digits and 23 injured tendons. Nine had neurovascular injuries. Ultrasound scans were obtained at a mean of 50 days postoperatively. The majority of Strickland scores were good/excellent (eight) or fair (six). Three had poor scores. All repairs were imaged intact. Vascularity was increased in two patients. High-quality images of flexor tendons, repair sites, neurovascular bundles, and annular pulleys were obtained consistently (Figs. 1 and 2). When adhesions were present, the distinction between tendon and scar tissue was difficult but possible. On dynamic scanning, tendon glide was easily visualized.Fig. 1: Transverse color Doppler image of a digit in which the radial digital artery but not the ulnar digital artery has been repaired. The flexor tendons are visible in the center of the image, with the two flexor digitorum superficialis slips inferior to the flexor digitorum profundus tendon.Fig. 2: Transverse view of zone 2 flexor digitorum profundus repair close to the proximal interphalangeal joint. The two white spots at the center top part of the image are end-on views of the suture material. The flexor digitorum superficialis slips are directly underneath the repaired flexor digitorum profundus tendon.On average, flexor tendon repair sites were 50 percent thicker in the anteroposterior diameter and 25 percent wider in the radioulnar diameter compared with unrepaired tendons (p = 0.001). Two digits had unimpaired tendon glide, six had mild impairment, six had moderate impairment, and three had severe impairment of glide. Sixty percent of those with good/excellent Strickland scores had good tendon mobility compared with 25 percent of those with fair scores. Ultrasound provided tangible, clinically relevant information about surgical repairs and clinical progress of patients. High-frequency linear array probes of a small size are ideal for hand imaging, providing clear images with excellent resolution of anatomical structures and dynamic images of tendon glide.4,5 Our study confirmed the feasibility of using ultrasound in this patient cohort. Ultrasound is useful in identifying tendon rupture or excessive adhesions, and could be used as a method of stratifying patients with poor outcomes to the appropriate rehabilitation program. Nora Nugent, F.R.C.S.I.(Plast.) Department of Plastic and Reconstructive Surgery Joseph Coyle, M.B., B.Ch. Josephine Barry, M.R.C.P., F.R.C.R. Department of Radiology Michael O'Shaughnessy, F.R.C.S.(Plast.) Department of Plastic and Reconstructive Surgery, Cork University Hospital, Wilton, Cork, Ireland DISCLOSURE No financial support was received for this study and none of the authors has any financial interests to declare.