Acellular and Glutaraldehyde‐Preserved Tendon Allografts for Reconstruction of Superficial Digital Flexor Tendon in Bovines: Part I – Clinical,Radiological and Angiographical Observations

Sixteen tenorrhaphies were performed at the mid‐metatarsal region in eight buffalo calves under lignocaine epidural analgesia. A 2 cm long gap was created in the superficial digital flexor (SDF) tendon and immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde‐preserved tendon allografts in group II. In group III, the defect was repaired with autografts. This group served as control. The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Diclofenac sodium and Enrofloxacin was given post‐operatively for 5 days. Clinical examination revealed significant increase (P < 0.05) in rectal temperature, heart and respiratory rate for 3–4 post‐operative days in all the animals. Mild pain and exudation as well as early restoration of tendon gliding movements and weight‐bearing were observed earlier in group I in comparison with group II. Air‐tendograms revealed early organization, minimal adhesion formation and lesser thickening of tendon at the reconstructive site in the acellular group whereas in the glutaraldehyde group dense homogenous swelling with adhesions was seen along the flexors. Angiography on day 30 showed that the area of proximal and distal host tendon graft junction appeared hypervascularized, whereas the area occupied by the graft appeared relatively less vascularized. Normal vascularization was observed on day 90 in all the three groups.     

Carbon Fibres and Plasma‐Preserved Tendon Allografts for Gap Repair of Flexor Tendon in Bovines: Clinical,Radiological and Angiographical Observations

Twenty‐four tenorrhaphies were performed at the mid‐metatarsal region in 12 crossbred calves under xylazine–ketamine spinal analgesia. A 2.5‐cm long gap was created in the superficial digital flexor (SDF) tendon and immediately repaired with carbon fibres in the animals of group I and with plasma‐preserved tendon allografts in group II. Clinical examination revealed a slight increase (P > 0.05) in rectal temperature, heart and respiratory rate for 2–4 days post‐operation in both groups. Milder pain and exudation as well as earlier restoration of tendon gliding movements and weight bearing were observed in group I as compared to group II. Air‐tendogram in the carbon fibre group on day 30 revealed restoration of continuity across the defect of the tendon, whereas, in the allograft group, a dense homogeneous swelling was seen along the flexors. Regression of peritendinous adhesions and swelling at the reconstructed site at later stages was seen in both groups. Angiography showed hypervascularization at the reconstructed site on day 14 in the carbon fibre group, however, in the allograft group the site appeared to be relatively avascular. On days 30 and 90, blood vessels were normally organized in both groups.     

A Preliminary Study on the Effect of Ultrasound Therapy on the Healing of Surgically Severed Achilles Tendons in Five Dogs

This study was conducted on the left Achilles tendon in five clinically normal dogs. The Achilles tendon was surgically exposed and severed 3–4 cm proximal to the point of its insertion. Tenorrhaphy was undertaken by the application of three sutures on the various tendon units of the Achilles tendon using single locking‐loop sutures with polyamide no. 1‐0. The superficial digital flexor tendon was sutured with catgut using two horizontal mattress sutures. No ultrasound therapy was used in the animals of group I (control). Ultrasound therapy was given to the animals of group II (treated) starting from the third day post‐operatively at 0.5 W/cm² for 10 min daily for 10 days. A cortical screw was used for immobilization of the tibiotarsal joint which was removed 4 weeks after tenorrhaphy. Post‐operatively, healing of the Achilles tendon was monitored using clinical observations, ultrasonography, gross and histomorphological observations at various intervals up to 120 days in both groups. Clinically, the dogs showed significant lameness for the first 4–5 days, which disappeared earlier in the ultrasound‐treated (group II) animals than the controls (group I). Extension and flexion of the hock joint were found to be near normal at 6 weeks after the repair of the Achilles tendon. Ultrasonography showed anechoic to hypo‐echoic echo‐texture on days 3 and 7 after repair. By day 40, the echo‐texture started to improve to hypo‐echoic in group II, but in group I anechoic areas were still observed. However, the tendon showed near normal mottled hypo‐ to hyper‐echoic texture in both groups by day 120. Gross observations suggested that the Achilles tendon in group II showed comparatively fewer adhesions than in group I animals. Histologically, in group II (treated), on day 40, the union was comparatively better without any inflammatory reaction. Bundle formation had begun in the ultrasound‐treated animals which was not observed in the control animals. By day 90, more compact parallel bundle formation had taken place with minimum cellularity. Bundle formation was in its advanced stage in the treated animals. By day 120, the tendon tissue was comparatively acellular and looking like a normal tendon. The use of the cortical screw provided good immobilization and ultrasound therapy at 0.5 W/cm² enhanced the Achilles tendon healing in dogs.     

Nonsurgical treatment and early return to activity leads to improved Achilles tendon fatigue mechanics and functional outcomes during early healing in an animal model

Achilles tendon ruptures are common and devastating injuries; however, an optimized treatment and rehabilitation protocol has yet to be defined. Therefore, the objective of this study was to investigate the effects of surgical repair and return to activity on joint function and Achilles tendon properties after 3 weeks of healing. Sprague–Dawley rats (N = 100) received unilateral blunt transection of their Achilles tendon. Animals were then randomized into repaired or non‐repaired treatments, and further randomized into groups that returned to activity after 1 week (RTA1) or after 3 weeks (RTA3) of limb casting in plantarflexion. Limb function, passive joint mechanics, and tendon properties (mechanical, organizational using high frequency ultrasound, histological, and compositional) were evaluated. Results showed that both treatment and return to activity collectively affected limb function, passive joint mechanics, and tendon properties. Functionally, RTA1 animals had increased dorsiflexion ROM and weight bearing of the injured limb compared to RTA3 animals 3‐weeks post‐injury. Such functional improvements in RTA1 tendons were evidenced in their mechanical fatigue properties and increased cross sectional area compared to RTA3 tendons. When RTA1 was coupled with nonsurgical treatment, superior fatigue properties were achieved compared to repaired tendons. No differences in cell shape, cellularity, GAG, collagen type I, or TGF‐β staining were identified between groups, but collagen type III was elevated in RTA3 repaired tendons. The larger tissue area and increased fatigue resistance created in RTA1 tendons may prove critical for optimized outcomes in early Achilles tendon healing following complete rupture. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2172–2180, 2016.     

Oral ibuprofen: evaluation of its effect on peritendinous adhesions and the breaking strength of a tenorrhaphy

In a study of 21 primates, treatment with oral ibuprofen significantly reduced the force required for tendon gliding following flexor tendon injury in zone II. Tendons that were partially lacerated but not repaired required less force for tendon motion than those repaired. Ibuprofen also reduced the breaking strength of completely divided and repaired extensor tendons. The addition of a piece of chromic suture buried across the extensor tenorrhaphy site significantly increased the breaking strength of the repair in control and treated animals alike. These findings were observed at 4 and 6 weeks after tendon injury and repair. No adverse reactions to the medication were observed.     

Acellular and Glutaraldehyde‐Preserved Tendon Allografts for Reconstruction of Superficial Digital Flexor Tendon in Bovines: Part II – Gross,Microscopic and Scanning Electron Microscopic Observations

Sixteen tenorrhaphies were performed at mid‐metatarsal region in eight buffalo calves. A 2‐cm long gap was created in the superficial digital flexor (SDF) tendon in all animals. The gap was immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde‐preserved tendon allografts in group II, and in group III the defect was repaired with autografts (control group). The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Gross observation revealed filling of host tendon–graft junction with fibrous connective tissue. Increased vascularity was seen in group I when compared with group II and III. Graft was resorbed in animals of group I and III, whereas partial absorption of graft was seen in group II. Histological observations on day 30 revealed restoration of cellularity in acellular graft and fragmentation and resorption of glutaraldehyde‐preserved graft. Graft was replaced by newly formed fibrous connective tissue. Tissue reaction around polygalactin suture consisted of plasma cells, lymphocytes and macrophages. On day 90, most of the acellular graft was replaced by newly formed fibrous connective tissue. In group II the majority of graft portion remained at the site and was in a state of resorption. In the control group it was difficult to distinguish between the host tendon and the graft. Scanning electron microscopical observation showed densely packed neoformed tissue at host tendon–graft junction. Hydrolysis and invasion of connective tissue between polygalactin suture filaments, resorption of graft with cavity formation and dissolution of ground substance were observed.     

The comparison of macroscopic and histologic healing of side-to-side (SS) tenorrhaphy technique and primer tendon repair in a rabbit model

Introduction

The side-to-side (SS) tenorrhaphy technique has been used in tendon transfer surgery. The mechanical properties of SS tendon suture have been studied previously. However, the histo-pathological healing of the SS tenorrhaphy of the tendons is unknown. The aim of this study was to assess the gross and histological effects of SS tenorrhaphy in a rabbit model.

Materials and methods

Twenty New Zealand rabbits were used. The extensor hallucis longus and tibialis anterior tendon were sewed SS at the level distal to the ankle joint. The patellar tendon (PT) at the same side was used as control group. A unilateral midline incision was made and repaired with a single suture. The animals were killed at the 12th week postoperatively. The histological sections were obtained from the side of surgery from each group. Each sample was stained with hematoxylene and eosin (H&E). Gross and microscopic healing was compared between the two groups.

Results

Gross examination of the control group showed complete healing with a thin peri-tendinous sheath formation around the suture site, whereas in the study group, a thick peri-tendinous sheath was formed around the area of the tendon–tendon anastomosis. In the control group, at the 12th week after surgery, the healing was almost completed in all samples. In the study group, a thick fibro vascular sheath has formed around the side of anastomosis. In all specimens few inter-digitations were observed between the tendons;however, the trough was still present.

Conclusion

The result of the current study showed that histological healing and union of SS tenorrhaphy differ from that in primary tendon injury and healing. Further studies are required to clarify the healing stages at the tenorrhaphy site.     

医用隔离材料防止肌腱粘连的实验研究

目的 通过动物实验比较目前较成熟的几种防肌腱粘连的材料,为临床提供依据.方法 雄性新西兰大白兔40只,随机分为4组,每组lO只,分别取左后肢第二、三趾为组内配对.在实验动物第二趾近节将屈肌腱切断后,用改良Kessler法缝合;对照组(A1)直接闭合切口,实验组分别在缝合口周围涂抹透明质酸钠(B1)、几丁糖(c1)、生物蛋白胶(D1)后闭合切口;各组第三趾缝合肌腱后加用聚乳酸可吸收膜包绕吻合口(A2、B2、C2及D2组).6周后对肌腱行大体、组织学观察及生物力学测试.结果 大体及光镜观察显示各实验组粘连程度均低于对照组A1,其中B1和C2组粘连程度最低.肌腱拉出距离及总活动度比值各组与对照组比较差异均有统计学意义(P＜0.05).各组最大拉力数值差异无统计学意义(P＞0.05).结论 聚乳酸可吸收医用膜、生物蛋白胶、透明质酸钠、几丁糖及其配对组合均有助于减少肌腱粘连,并且不影响肌腱愈合强度.其中,透明质酸钠组和几丁糖+医用膜组粘连程度最低,疗效显著.     

Treatment of partial flexor tendon lacerations: the effect of tenorrhaphy and early protected mobilization

Controversy exists in the literature regarding the proper treatment of partial flexor tendon lacerations. In this study, a novel nonweightbearing canine model was developed in order to closely approximate human flexor tendon conditions. The relative effects of immobilization, early protected mobilization, tenorrhaphy, and no repair of flexor tendon healing were evaluated by paired comparisons of four experimental groups (24 animals). Parameters evaluated after a 35-day healing period included tendon excursion, breaking strength, energy absorption, and stiffness. The contralateral digit-matched profundus tendon served as a normal control. Eight additional animals were studied histologically and by scanning electron microscopy. Data analysis revealed statistically significant adverse effects on breaking strength, stiffness, and energy absorption when repaired by modified Kessler technique. Early motion improved excursion and stiffness significantly, and resulted in more nearly normal tendon morphology than immobilized tendons. Thus, we conclude that partial flexor tendon lacerations of 60% cross-sectional area are optimally treated without tenorrhaphy and with early mobilization.     

Surface modification counteracts adverse effects associated with immobilization after flexor tendon repair

Although post‐rehabilitation is routinely performed following flexor tendon repair, in some clinical scenarios post‐rehabilitation must be delayed. We investigated modification of the tendon surface using carbodiimide derivatized hyaluronic acid and lubricin (cd‐HA‐Lub) to maintain gliding function following flexor tendon repair with postoperative immobilization in a in vivo canine model. Flexor digitorum profundus tendons from the 2nd and 5th digits of one forepaw of six dogs were transected and repaired. One tendon in each paw was treated with cd‐HA‐Lub; the other repaired tendon was not treated. Following tendon repair, a forearm cast was applied to fully immobilize the operated forelimb for 10 days, after which the animals were euthanized. Digit normalized work of flexion (nWOF) and tendon gliding resistance were assessed. The nWOF of the FDP tendons treated with cd‐HA‐Lub was significantly lower than the nWOF of the untreated tendons (p < 0.01). The gliding resistance of cd‐HA‐Lub treated tendons was also significantly lower than that of the untreated tendons (p < 0.05). Surface treatment with cd‐HA‐Lub following flexor tendon repair provides an opportunity to improve outcomes for patients in whom the post‐operative therapy must be delayed after flexor tendon repair. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1940–1944, 2012     

肌腱缝合后鞘内置入法预防Ⅱ区屈肌腱粘连的实验研究

目的 探讨一种屈肌腱修复新方法即腱缝合后鞘内置入法，并观察其在鸡Ⅱ区屈肌腱损伤修复中的疗效，揭示其预防屈肌腱术后粘连机理，为临床应用提供依据。方法 选用健康白色纯种Leghorn鸡40只，以第三趾趾深屈肌腱屈曲型损伤为实验模型，随机分组，左右足配对设计，一侧为实验组，用腱缝合后鞘内置入法修复肌腱；另一侧为对照组，切开腱鞘修复肌腱，缝合腱鞘。分别于术后1、2、4、8周进行大体观察、组织学观察、生物力学测定。结果 1周后大体观察、肌腱滑动距离，实验组与对照组间无显著性统计学意义。2、4、8周后大体观察粘连情况、肌腱滑动距离、各是关节屈曲角度、组织学观察结果，两组间有显著性差异，4周后腱及鞘缝合口间距与肌腱粘连带宽度比，两组间均有显著性差异。结论 腱缝合后鞘内置入法在Ⅱ区屈肌腱修复中能有效减轻肌腱术后粘连，尤其是致密粘连的形成，在提高肌腱术后功能上优于单纯腱鞘闭合，可以适用于临床。     

可吸收防粘连膜在肌腱修复中的应用疗效观察

目的观察可吸收防粘连膜预防肌腱修复术后粘连的临床应用效果。方法将38例急性手部肌腱损伤患者随机分为两组,肌腱缝合后分别采用包绕成都迪康公司生产的聚-DL-乳酸可吸收防粘连膜和早期使用动力性支具两种方法治疗。试验组15例65腱,涉及屈肌腱10例51腱,7例伴血管神经损伤;伸肌腱5例14腱。对照组23例76腱,涉及屈肌腱11例32腱,6例伴血管神经损伤;伸肌腱12例44腱。对损伤肌腱均采用5-0肌腱缝线行改良Kessler法修复。试验组术后以石膏托固定伤手于屈腕、屈掌指关节位(屈肌腱损伤者)或伸腕、伸指位(伸肌腱损伤者),鼓励患者早期行手指活动,对照组术后第3天改用动力性支具。4周后拆除石膏托或动力性支具,行主动屈伸锻炼,辅以中药熏洗。结果试验组1例伤口延迟愈合,2例肌腱修复处皮肤出现局限性硬结,其余伤口均一期愈合。术后随访6～14个月,平均8.7个月。术后屈肌腱功能用TAM法评定,伸肌腱功能用Miller法评定。试验组综合优良率为93.85%(61/65),对照组综合优良率为90.79%(69/76)(P>0.05),两组间无显著性差异。结论可吸收防粘连膜能有效防止肌腱损伤修复术后粘连的形成,同时避免了动力性支具安装的繁琐操作,消除了医患双方在使用支具过程中对可能发生肌腱断裂的担忧,具有良好的应用前景。     

The effects of chronic unloading and gap formation on tendon‐to‐bone healing in a rat model of massive rotator cuff tears

The objective of this study was to understand the effect of pre‐repair rotator cuff chronicity on post‐repair healing outcomes using a chronic and acute multi‐tendon rat rotator cuff injury model. Full‐thickness dual tendon injuries (supra‐ and infraspinatus) were created unilaterally in adult male Sprague Dawley rats, and left chronically detached for 8 or 16 weeks. After chronic detachment, tears were repaired and acute dual tendon injuries were created and immediately repaired on contralateral shoulders. Tissue level outcomes for bone, tendon, and muscle were assessed 4 or 8 weeks after repair using histology, microcomputed tomography, biomechanical testing, and biochemical assays. Substantial gap formation was seen in 35% of acute repairs and 44% of chronic repairs. Gap formation negatively correlated with mechanical and structural outcomes for both healing time points regardless of injury duration. Bone and histomorphometry, as well as biomechanics, were similar between acute and chronic injury and repair regardless of chronicity and duration of healing. This study was the first to implement a multi‐tendon rotator cuff injury with surgical repair following both chronic and acute injuries. Massive tear in a rodent model resulted in gap formation regardless of injury duration which had detrimental effects on repair outcomes. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:439–447, 2014.     

Ultrasound accelerates functional recovery after peripheral nerve damage

OBJECTIVE: Axonal injury in the peripheral nervous system is common, and often it is associated with severe long-term personal and societal costs. The objective of this study is to use an animal model to demonstrate that transcutaneous ultrasound can accelerate recovery from an axonotmetic injury. METHODS: The sciatic nerve of adult male Lewis rats was crushed in the right midthigh to cause complete distal degeneration of axons yet maintain continuity of the nerve. Beginning 3 days after surgery, various transcutaneous ultrasound treatments or sham treatments were applied 3 days per week for 30 days to the crush site of rats that were randomly assigned to two groups. In the preliminary experiments, there were three animals in each ultrasound group and two control animals. In the final experiment, there were 22 animals in the ultrasound group and 20 animals in the control group. Recovery was assessed by use of a toe spread assay to quantify a return to normal foot function in the injured leg. Equipment included a hand-held transducer that emitted continuous-wave ultrasound. The most successful ultrasound protocol had a spatial peak, time-averaged intensity of 0.25 W/cm2 operated at 2.25 MHz for 1 minute per application. RESULTS: Rats subjected to the most successful ultrasound protocol showed a statistically significant acceleration of foot function recovery starting 14 days after injury versus 18 days for the control group. Full recovery by the ultrasound group occurred before full recovery by the control group. CONCLUSION: Transcutaneous ultrasound applied to an animal model of axonotmetic injury accelerated recovery. Future studies should focus on identification of the mechanism(s) by which ultrasound creates this effect, as a prelude to optimization of the protocol, demonstration of its safety, and its eventual application to humans.     

Effects of tenorraphy on the gliding function and tensile properties of partially lacerated canine digital flexor tendons

Management of a partially lacerated digital flexor tendon within zone II remains controversial. To address this issue, we undertook an evaluation of the impact of tenorrhaphy on the gliding function and tensile properties of canine flexor tendons with lacerations involving either 30% or 70% of their cross-sectional area. Assessment of tendon excursion and joint rotation after 6 weeks of postoperative controlled passive mobilization failed to reveal any statistically significant benefit from tenorrhaphy on the gliding function. In fact, we demonstrated a significant negative effect of repair on tendons with 30% lacerations. Moreover, no significant differences between the structural properties or integrity of the repaired and nonrepaired tendons could be demonstrated. Thus, in light of the inherent tensile properties in these partially lacerated tendons, our data suggest that digital function of partially lacerated tendons of up to 70% of the cross-sectional area may be preserved without primary repair. However, additional work is needed to more definitively address this issue in a clinical context.     

The Importance of Controlled Passive Mobilization on Flexor Tendon Healing: A Biomechanical Study

The effects of controlled passive motion on primary tendon repair were studied using the canine forepaw flexor apparatus as experimental model. The animals were divided into seven groups based on duration (3 to 12 weeks post repair) and mode of immobilization and partial mobilization. The repaired tendons were subjected to biomechanical evaluation of their gliding function and tensile strength characteristics. The results showed positive effects of controlled passive motion on tendon repair. The rate of tendon repair was significantly improved over those animals that were continuously immobilized. At 12 weeks, the repaired flexors from the motion group had regained over one-third of the ultimate tensile load as compared to their contralateral intact controls. Of equal importance is that these repaired tendons maintained good gliding function within the sheath during the repair process. The gliding function of these tendons was also significantly better than those subjected to continuous immobilization.     

Low‐intensity pulsed ultrasound accelerates fracture healing by stimulation of recruitment of both local and circulating osteogenic progenitors

We investigated the effect of low‐intensity pulsed ultrasound (LIPUS) on the homing of circulating osteogenic progenitors to the fracture site. Parabiotic animals were formed by surgically conjoining a green fluorescent protein (GFP) mouse and a syngeneic wild‐type mouse. A transverse femoral fracture was made in the contralateral hind limb of the wild‐type partner. The fracture site was exposed to daily LIPUS in the treatment group. Animals without LIPUS treatment served as the control group. Radiological assessment showed that the hard callus area was significantly greater in the LIPUS group than in the control group at 2 and 4 weeks post‐fracture. Histomorphometric analysis at the fracture site showed a significant increase of GFP cells in the LIPUS group after 2 weeks (7.5%), compared to the control group (2.4%) (p < 0.05). The LIPUS group exhibited a significantly higher percentage of GFP cells expressing alkaline phosphatase (GFP/AP) than the control group at 2 weeks post‐fracture (5.9%, 0.3%, respectively, p < 0.05). There was no significant difference in the percentage of GFP/AP cells between the LIPUS group (2.0%) and the control group (1.4%) at 4 weeks post‐fracture. Stromal cell derived factor‐1 and CXCR4 were immunohistochemically identified at the fracture site in the LIPUS group. These data indicate that LIPUS induced the homing of circulating osteogenic progenitors to the fracture site for possible contribution to new bone formation. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1516–1521, 2012     

Barbed suture vs conventional tenorrhaphy: biomechanical analysis in an animal model

BackgroundThe advantages of barbed suture for tendon repair could be to eliminate the need for a knot and to better distribute the load throughout the tendon so as to reduce the deformation at the repair site. The purpose of this study was to evaluate the breaking force and the repair site deformation of a new barbed tenorrhaphy technique in an animal model.ResultsThe two-sample Student t-test demonstrated a significant increase in 2-mm gap formation force and in breaking force with barbed sutures, independently from suture material, when compared to traditional Kessler suture. Concerning the tendon profile, we registered less bunching at the repair site in the two barbed groups compared with the Kessler group.ConclusionsThis study confirms the promising results achieved in previous ex vivo studies about the use of barbed suture in flexor tendon repair. In our animal model, tenorrhaphy with Quill™ SRS suture guarantees a breaking force of repair that exceeds the 40–50 N suggested as sufficient to initiate early active motion, and a smoother profile at the repair site.Level of evidence Not applicable.     

Sodium cromolyn reduces expression of CTGF,ADAMTS1, and TIMP3 and modulates post‐injury patellar tendon morphology

The purpose of this study was to determine whether administration of a mast cell inhibitor (sodium cromolyn, SC) would influence tendon repair and extracellular matrix gene expression following acute injury. CD1 mouse patellar tendons were unilaterally injured and mast cell prevalence was determined. The effect of SC injection on tendon hypercellularity, cross‐sectional area, collagen organization, and expression of extracellular matrix‐related genes was examined. Mast cell prevalence was markedly increased in injured patellar tendons (p = 0.009), especially at 8 weeks post‐injury (p = 0.025). SC injection increased collagen organization compared to uninjected animals at 4 weeks and attenuated the development of tendon hypercellularity and tendon thickening post‐injury. Expression of CTGF, ADAMTS1, and TIMP3 in injured tendon was reduced in the SC group. SC injections moderated the structural alterations of healing tendon in association with downregulation of several genes associated with tendon fibrosis. This work corroborates previous findings pointing to a role of mast cells in tendon repair. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:678–683, 2011     

Biomechanical comparison of new Achilles tendon rupture repair technique the “Giftbox” versus the Krackow technique in New Zealand white rabbits: An experimental animal study

IntroductionTo compare the strength between the Achilles tendons repaired with the “Giftbox” and the Krackow techniques in New Zealand white rabbits post six weeks of tendon healing.Materials and MethodsEight rabbits were randomized into Giftbox and Krackow groups. Tenotomy was performed on the Achilles tendon of one side of the lower limb and repaired with the respective techniques. The contralateral limb served as control. Subjects were euthanized six weeks post-operative, and both repaired and control Achilles tendons were harvested for biomechanical tensile test.ResultsThe means of maximum load to rupture and tenacity in the Giftbox group (156.89 ± 38.49 N and 159.98 ± 39.25 gf/tex) were significantly different than Krackow's (103.55 ± 27.48 N and 104.91 ± 26.96 gf/tex, both p = 0.043).ConclusionThe tendons repaired with Giftbox technique were biomechanically stronger than those repaired with Krackow technique after six weeks of tendon healing.