Letter about a published paper

Abstract

I read these two articles from Singapore presenting experimental studies on the strength of Pulvertaft weave tendon repairs with interest. I congratulate the authors on their work aimed at defining optimal methods of joining tendons. However, I have some concerns regarding the conclusions and clinical application of the findings. The first study by Choke et al. (2020) investigates the effect of the number of weaves on the initial tensile strength of the repair by comparing one, two and three weaves. The results suggest that the twoweave repair had similar tensile strength (91 N) to the three-weave repair (89 N). The single weave repair was slightly weaker (75 N) but still appeared strong enough to allow early active motion after flexor tendon repair. The authors recommend using two weaves. All repairs were sutured with eight interrupted nylon sutures. It seems unlikely that the weave itself confers much initial strength to the repair, but may be important once the tendon starts to heal. Initial strength is likely to rely on the suturing. Hence, the results suggest that when tendons are repaired with the same number and pattern of sutures the initial strength is similar. I am doubtful if a reliable conclusion can be made regarding the number of weaves. In practice, a repair with more weaves will have more overlap and more sutures and is therefore likely to be stronger. The second study by Xing Fu Hap et al. (2020) tests the strength of a barbed suture (V-Loc) for the Pulvertaft weave compared with conventional monofilament sutures (Prolene and Ethilon). Two weaves were used for all repairs. For the Prolene and Ethilon repairs four mattress and one figure-ofeight sutures were inserted. For the barbed suture a continuous strand was inserted, locked at each end of the tendon overlap. The tensile strength of the convention suture repairs (Prolene1⁄4 39.8 N and Ethilon1⁄4 49.1 N) were rather less than those reported by Choke et al. using eight interrupted sutures. The barbed suture repair appeared stronger with a tensile strength of 110.9 N and greater stiffness. However, this could have been the result of using a continuous suture rather than the suture material. Continuous suture repairs have been reported to be stronger and stiffer than those secured with interrupted mattress sutures (Brown et al., 2010). In a further study, Choke et al. (2021) used V-Loc suture material as eight interrupted sutures and found no difference in strength to conventional suture materials. These studies rather suggest that the initial strength of an overlapping tendon repair is related mainly to the number and pattern of the sutures used rather than the number of weaves or the suture material. However, study of how different tendon repairs perform during healing could provide useful information.