Robert M. Szabo MD MPH1 and Shima Sokol MD2 1 Department of Orthopaedic Surgery, University of California Davis, Davis, CA, USA 2 Albert Einstein College of Medicine, Bronx, NY, USA Biomechanical studies have shown the strength of the repair increases with the number of suture strands crossing the repair site. However, suture techniques using more strands across the repair site are technically demanding and require increased manipulation of the tendon ends. Multistrand repairs are also bulkier, which may compromise tendon gliding under the pulleys. A tendon repair must be strong enough to allow for early ROM without creating too much bulk to impair tendon gliding within zone II. There is one randomized controlled trial (RCT),1 one retrospective comparative study,2 two level III meta‐analyses,3,4 and one level IV systemic review comparing two‐strand repair to multistrand repair.5 Overall, rupture rates for flexor tendon repairs using all methods average approximately 4%.6,7 Although in vitro studies have confirmed increasing the number of core sutures across the repair site increases the strength of tendon repair in vitro,8–14 the clinical benefits of increasing the number of core sutures have not been proven. Several papers have tried to determine whether there is a benefit of multistrand repair over two‐strand core suture repair. Navali and Rouhani published an RCT comparing flexor tendon repairs in zone II performed with a two‐strand or four‐strand core‐suture repair.1 They followed a passive ROM protocol after surgery which may have negated the principal advantage of multistrand repairs (early active motion). There was no statistical difference in clinical outcome between the two groups. There were two tendon ruptures in the two‐strand repair group and none in the four‐strand repair group. This difference was not statistically significant. Hoffman et al. compared the clinical outcomes of 46 patients (51 digits) undergoing a six‐strand Lim/Tsai repair to 25 patients (26 digits) treated with a two‐strand modified Kessler stitch in zone II flexor tendon repairs.2 The complication rate was lower in the six‐strand group (4%) than in the two‐strand group (23%). The rupture rate was also lower in the six‐strand group (2% vs 11% in the other group), but this was not statistically significant. The two groups followed different rehabilitation protocols, confounding the results. A systematic review of two‐strand versus multistrand core suture techniques for flexor tendon repair found no difference in functional outcome.4 There was a trend toward lower rupture rates in the multistrand repair group, but this difference was not clinically significant. Other meta‐analyses evaluating flexor tendon repairs in all zones have also failed to find a statistically significant difference in outcomes or rupture rates between two‐strand and multistrand repairs.3,5 One study found that a modified Kessler technique decreased the risk of adhesions by 134%.6 Traditionally, the A2 and A4 pulley have been preserved, repaired, or reconstructed during zone II flexor tendon repair to prevent bowstringing. Release or venting of these essential pulleys during zone II flexor tendon repair can facilitate repair, may improve tendon excursion, and decrease work of flexion.15–22 The practice of venting essential pulleys during flexor tendon repair is gaining wide clinical acceptance. There are two level IV studies describing outcomes after complete release of the A4 pulley during flexor tendon repair.23–25 There is one small retrospective case series reporting the results of flexor tendon repair after complete release of the A2 pulley.24 Tang and colleagues published a large prospective study describing results after zone II flexor tendon repairs involving release of various portions (including the A2 and A4 pulley) of the flexor sheath.26
159 Flexor Tendon Injuries: Surgical Management
Clinical scenario
Top three questions
Question 1: In patients with acute zone II flexor tendon lacerations, does multistrand core‐suture repair result in fewer re‐ruptures and better range of motion (ROM) compared to two‐strand repairs?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
Resolution of the clinical scenario
Question 2: In patients undergoing zone II flexor tendon repair, does release of the A2 or A4 pulley result in poorer outcome or bowstringing compared to preservation of these annular pulleys?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
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