Core Suture Research Articles

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.

Effects of Different Core Suture Lengths on Tensile Strength of Multiple-Strand Sutures for Flexor Tendon Repair

PurposeTo compare 2 types of newly devised 8-strand quadruple-looped suture (QLS) techniques with a 6-strand triple-looped suture (TLS) technique; and to assess the effects of different core suture lengths (CSLs) (the length between 2 locking sites of a suture strand) within each suture row on tensile strength.MethodsWe repaired 24 flexor tendons from 12 rabbits using the TLS and QLS techniques, with equal CSL (QLS) or unequal CSL (unequal QLS) among each suture row. The QLS was composed of 4 looped sutures on the anterolateral and posterolateral aspects of the tendon. The cross-sectional area of the locking portion of each thread in the QLS was equal to that in the TLS. In the QLS technique, the CSL on each aspect of the tendon was 13 mm. In the unequal QLS technique, the CSL on each aspect of the tendon was 13 and 17 mm. The load at 1- and 2-mm gaps, the maximum load until the 3-mm gap, and the ultimate load were compared among the 3 techniques.ResultsThe QLS was significantly stronger than the unequal QLS and the TLS for loads at 1-mm and 2-mm gaps, maximum load until 3-mm gap, and ultimate load. There was no significant difference between the unequal QLS and TLS techniques. The QLS technique showed an approximately 30% increase in gap resistance and ultimate strength compared with the TLS technique.ConclusionsThe QLS technique showed an estimated increase in tensile strength proportional to the number of suture strands compared with the TLS technique. Our study suggests that a consistent CSL in each suture row provides the highest strength in multistrand sutures consisting of the same configuration of suture rows.Clinical relevanceThe QLS technique may reduce the risk for tendon rupture associated with early active mobilization after flexor tendon repair.

Biomechanical Analysis of Patellar Tendon Repair With Knotless Suture Anchor Tape Versus Transosseous Suture

Background:Patellar tendon ruptures have routinely been repaired with transosseous suture tunnels. The use of knotless suture anchors for repair has been suggested as an alternative.Purpose:To compare the load to failure and gap formation of patellar tendon repair at the inferior pole of the patella with knotless suture anchor tape versus transosseous sutures. A secondary objective was to investigate whether either technique shows an association between bone density and load to failure.Study Design:Controlled laboratory study.Methods:A total of 20 human tibias with attached patellar and quadriceps tendons were sharply incised at the bone-tendon junction at the inferior pole of the patella. A total of 10 tendons were repaired using 2 knotless suture anchors in the inferior pole of the patella and a single suture tape with 2 core sutures. The other 10 tendons were repaired using No. 2 suture passed through 3 transosseous tunnels. A distracting force was then applied through the suture in the quadriceps tendon. Gap distance through load cycling at the repair site and maximum load at repair failure were then measured. Bone density was measured using computed tomography scanning.Results:No difference was found in the mean load to failure of knotless patellar tendon repair versus transosseous suture repair (367.6 ± 112.2 vs 433.9 ± 99 N, respectively; P = .12). After 250 cycles, the mean repair site gap distance was 0.85 ± 0.45 mm for the knotless patellar tendon repair versus 2.94 ± 2.03 mm for the transosseous suture repair (P = .03). A small correlation, although not statistically significant, was found between bone density and load to failure for the knotless tape repair (R 2 = 0.228; P = .66). No correlation was found between bone density and load to failure for the transosseous repair (R 2 = 0.086; P = .83).Conclusion:Suture tape repair with knotless anchors for repair of patellar tendon rupture has comparable load to failure with less gap formation than transosseous suture repair. There is a small correlation between bone density and failure load for knotless anchor repair, which may benefit from further investigation.Clinical Relevance:Using knotless suture anchors for patellar tendon rupture repair would allow for a smaller incision, less dissection, and likely shorter operating time.

Robust Suture Combination for Rat Flexor Tendon Repair Model

PurposeWe aimed to develop a rat flexor tendon repair model that could be applied to experiments in similar clinical settings.MethodsWe prepared 3 different combinations of sutures in rat flexor tendons: group A had 3 single peripheral sutures plus a 2-strand core suture; group B had 3 figure-of-eight peripheral sutures alone; and group C had 3 figure-of-eight peripheral sutures plus a 2-strand core suture. We examined the in vitro tensile strength of the repaired tendons by a biomechanical test, the rerupture rate within 3 weeks, and histological findings in vivo.ResultsGroup C displayed the greatest ultimate strength by the mechanical test. The flexor tendons in group C did not rerupture within 3 weeks after surgery, whereas many of those in groups A and B reruptured. Fibrous scar tissue was observed in the gap of the tendon stumps in groups A and B, but not in group C.ConclusionsThe combination of figure-of-eight peripheral sutures and a 2-strand core suture provided the repaired rat flexor tendon with enough strength to prevent rerupture without cast fixation or immobilization after surgery.Clinical relevanceThis combination of sutures is useful to reproduce flexor tendon repair similar to that performed in clinical settings and will contribute to various translational experiments in vivo.

An analysis of the effect of the technique of the repair and postoperative rehabilitation protocol on the treatment outcomes of flexor tendon injuries: a review

Abstract This study covers updated information on the methods of the repair of flexor tendon injuries, postoperative rehabilitation protocols and their effect on treatment outcomes. Contemporary techniques of flexor tendon repair are based on combinations of various types of core sutures and circumferential epitenon sutures. Literature shows a tendency of replacing earlier 2-strand core tendon sutures with novel multistrand core sutures, however the results of meta-analyses do not confirm any definitive superiority over traditional techniques. Likewise, literature does not provide conclusive evidence that early active postoperative mobilization results in better outcomes than active-passive and controlled passive mobilization techniques. The choice of the method of flexor tendon repair and postoperative rehabilitation protocol depends only in part on scientific evidence, but more on individual or institutional preference of the surgeon.

Effect of partial vs complete circumferential epitendinous suture placement on the biomechanical properties and gap formation of canine cadaveric tendons.

To determine the effect of partial vs complete circumferential epitendinous suture (ES) placement in addition to a core suture on the biomechanical strength and gapping characteristics of repaired canine tendinous constructs. Ex vivo, biomechanical study. Thirty-six canine superficial digital flexor tendons. Superficial digital flexor tendons were randomly assigned to three groups (n = 12), sharply transected and repaired with a core locking-loop suture with Group 1 a partial circumferential ES, 180° on the palmar side; Group 2 a complete circumferential ES, 360° and double knotting technique; or Group 3 a complete circumferential ES, 360° and single knotting technique. After preloading, constructs were distracted to monotonic failure. Failure mode, gap formation, yield, peak, and failure forces were analyzed. Mean yield (group 1 = 68.6 N, group 2 = 106.5 N, group 3 = 114 N, P < .013), peak (group 1 = 92.8 N, group 2 = 134.6 N, group 3 = 147.3 N; P < .001), and failure (group 1 = 88.7 N, group 2 = 133.0 N, group 3 = 145.5 N, P < .001) loads differed between groups. No difference in yield (P = .874), peak (P = .434), or failure load (P = .434) was detected between complete circumferential ES groups. Force to create 1-mm (P < .001) and 3-mm (P < .038) gap formation was greater in specimens with complete vs partial circumferential ES placement. Complete circumferential ES repairs failed primarily by suture pull-through compared with suture breakage in most partial circumferential ES constructs. Addition of a complete circumferential ES with a single or double knotting technique increased the biomechanical strength of normal tendon repairs while reducing gap formation compared with partial ES placement alone. Complete circumferential ES is recommended over partial ES placement.

Four-strands versus six-strands core sutures technique for surgical management of acute zone II flexor tendon injury

Four-strands versus six-strands core sutures technique for surgical management of acute zone II flexor tendon injury

Outcomes and rupture rate of the “Adelaide” four-strand repair for zone 2 flexor tendon injuries over a 10-year period

Multi-strand core suture techniques combined with early active mobilization regimens have demonstrated improved functional outcomes in zone II flexor tendon injuries. This study evaluated the integrity of the “Adelaide” four-strand repair and assessed its outcome on function. All zone II flexor tendon repairs were identified from a prospectively collected database from 2002 to 2012. Patient demographics, number and type fingers injured, neurological deficits, length to surgery, and rupture rates were recorded. Strickland and Modified Strickland measurements assessed the functional outcome. Follow-up was for 12 weeks post-operatively. A total of 167 patients and 197 fingers were identified, of which 111 and 125 respectively had complete data for analysis. Patient demographics included 93 males and 18 females with a mean age of 28.6 years (15–68). The most common finger injured was index 41/125 (35%), 105/111 (95%) had surgery within 3 days, 69/125 (55%) had an associated digital nerve injury, and 44/111 (40%) were smokers. Strickland and Modified Strickland calculations demonstrated 92/125 (74%) patients had a good/excellent result, 25/125 (20%) fair, and 8/125 (6%) had a poor result. Rupture rate was 5/125 (4%). The “Adelaide” repair combined with early active mobilization achieves a good functional outcome with low rupture rates. Level of evidence: Level III; therapeutic study

Biomechanical evaluation of an autologous flexor digitorum lateralis graft to augment the surgical repair of gastrocnemius tendon laceration in a canine ex vivo model.

To evaluate the effect of an autologous flexor digitorum lateralis (FDL) graft to augment a three-loop pulley (3LP) core repair in a canine cadaveric gastrocnemius tendon (GT) laceration model. Ex vivo, biomechanical study. Twenty-six canine cadaveric hind limbs. Tendons were divided into two groups (n = 13). After sharp transection, paired GT were repaired with 3LP or 3LP + FDL tendon augmentation. Yield, peak and failure loads, tensile loads required to create 1 and 3-mm gapping, and failure modes were analyzed. Significance was set at P < .05. Yield and failure force (mean ± SD) for 3LP + FDL were 134.9 ± 44.1 N and 205.4 ± 46.4 N, respectively, which were greater than for 3LP alone (67.9 ± 12.2 N and 91.8 ± 9.9 N, respectively, P < .0001). No constructs (0%) formed 1 or 3-mm gaps in the 3LP + FDL graft group compared with 84% and 39% for 3LP, respectively (P < .0001). Failure modes were different between groups (P < .001), with 85% of 3LP + FDL constructs failing by tissue rupture at the myotendinous junction, distant to the repair site. Addition of an autologous FDL graft to a core 3LP tendon repair increased yield, peak, and failure forces by twofold, 2.3-fold, and 2.2-fold, respectively, compared with core 3LP alone while preventing the occurrence of gap formation. Use of FDL tendon augmentation for GT laceration may increase repair site strength and resist gap formation better than 3LP core suture use alone. Additional studies are required in vivo to determine the effect of FDL graft augmentation on clinical function.

Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons.

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q suture, an alternative to peripheral sutures, is presented for the use in tendon repair. Its effects on gap formation and tensile strength of the repaired tendons were compared with conventional running peripheral sutures. Three 2-strand sutures and three 4-strand sutures were used in repairing porcine tendons. The time required for performing 2Q and running sutures were recorded. The repaired tendons were subjected to a cyclic loading test, and the cycle number, during which a 2-mm gap was formed, was determined. After the cyclic loading, the gap size at the tendon ends and the ultimate strength of the repaired tendons were measured. Augmentation with the Q sutures reduced the number of tendons showing 2-mm gaps at tendon ends during cyclic loading. With addition of Q sutures 2-strand sutures significantly increased the ultimate strength of the repaired tendons and 4-strand sutures decreased the gap distance at the repair site of tendons. The time required for performing 2Q sutures was significantly less than that for running sutures. Therefore, we conclude that the Q suture is efficient in enhancing the tensile resistance and tendon repair strength and can be an alternative to conventional peripheral sutures.

Biomechanical analysis of a new 8-strand technique for flexor tendon repair

We sought to compare the strength and rupture sites of a new 8-strand suture technique with those of an established 6-strand flexor tendon repair through biomechanical analysis. This new 8-strand suture pattern places minimal suture material in the remodeling zone and focuses on protecting the knot, a well-known weak point of the suture construct. The knot was buried within the tendon so as to not interfere with tendon gliding. In a biomechanical simulation, strength and rupture sites were compared with those of the 6-strand repair. We repaired a total of 54 porcine flexor tendons using one of the two techniques (n=27 each). Tensile strength at 2-mm gap formation and ultimate failure load were determined. Afterwards, we dissected the tendons to identify the rupture site of the suture material. The new 8-strand suture had a significant higher ultimate load to failure (87.7N) and 2-mm gap load (71.6N) compared to the 6-strand technique (57.7N and 45.9N) (P<0.001). Whereas the rupture site of the core suture in the 6-strand technique was mainly located next to the knot (81.5%), the suture seemed to fail independently from this weak spot in the 8-strand technique (11.1%). This new 8-strand technique achieves a strong flexor tendon repair in a biomechanical model. Additional cross-locking on either side of the knot seems to contribute to the repair's strength. The resulting higher ultimate failure load and 2-mm gap load may allow more aggressive active motion-based postoperative rehabilitation.

Microsurgical reconstruction affects the outcome in a translational mouse model for Achilles tendon healing.

SummaryBackgroundAnimal models are one of the first steps in translation of basic science findings to clinical practice. For tendon healing research, transgenic mouse models are important to advance therapeutic strategies. However, the small size of the structures complicates surgical approaches, histological assessment, and biomechanical testing. In addition, available models are not standardized and difficult to compare. How surgery itself affects the healing outcome has not been investigated yet. The focus of the study was to develop a procedure that includes a transection and microsurgical reconstruction of the Achilles tendon but, unlike other models, preserves the sciatic nerve. We wanted to examine how distinct parts of the technique influenced healing.MethodsFor this animal model study, we used 96 wild-type male C57BL/6 mice aged 8–12 weeks. We evaluated different suture techniques and macroscopically confirmed the optimal combination of suture material and technique to minimize tendon gap formation. A key element is the detailed, step-by-step illustration of the surgery. In addition, we assessed histological (Herovici and Alcian blue staining) outcome parameters at 1–16 weeks postoperatively. Microcomputed tomography (micro-CT) was performed to measure the bone volume of heterotopic ossifications (HOs). Biomechanical analyses were carried out using a viscoelastic protocol on the biomechanical testing machine LM1.ResultsA modified 4-strand suture combined with a cerclage for immobilization without transection of the sciatic nerve reliably eliminated gap formation. The maximal dorsal extension of the hindlimb at the upper ankle joint from the equinus position (limited by the immobilization cerclage) increased over time postoperatively (operation: 28.8 ± 2.2°; 1 week: 54 ± 36°; 6 weeks: 80 ± 11.7°; 16 weeks: 96 ± 15.8°, p > 0.05). Histological staining revealed a maturation of collagen fibres within 6 weeks, whereas masses of cartilage were visible throughout the healing period. Micro-CT scans detected the development of HOs starting at 4 weeks and further progression at 6 and 16 weeks (bone volume, 4 weeks: 0.07604 ± 0.05286 mm3; 6 weeks: 0.50682 ± 0.68841 mm3; 16 weeks: 2.36027 ± 0.85202 mm3, p > 0.001). In-depth micro-CT analysis of the different surgical elements revealed that an injury of the tendon is a key factor for the development of HOs. Immobilization alone does not trigger HOs. Biomechanical properties of repaired tendons were greatly altered and remained inferior 6 weeks after surgery.ConclusionWith this study, we demonstrated that the microsurgical technique greatly influences the short- and longer-term healing outcome. When the sciatic nerve is preserved, the best surgical reconstruction of the tendon defect is achieved by a 4-strand core suture in combination with a tibiofibular cerclage for postoperative immobilization. The cerclage promotes a gradual increase in the range of motion of the upper ankle joint, comparable with an early mobilization rehabilitation protocol. HO, as a key mechanism for poor tendon healing, is progressive and can be monitored early in the model.The translational potential of this articleThe study enhances the understanding of model dependent factors of healing. The described reconstruction technique provides a reproducible and translational rodent model for future Achilles tendon healing research. In combination with transgenic strains, it can be facilitated to advance therapeutic strategies to improve the clinical results of tendon injuries.

Chronic distal biceps avulsion treated with suture button

Distal biceps tendon avulsions account for 3%-10% of all biceps ruptures. Treated nonoperatively, these injuries lead to a loss of endurance, supination strength, and flexion strength compared with operative repair or reconstruction. Operative management of chronic injury has classically been with graft tissue to augment the contracted muscle. We present our results for chronic distal biceps avulsions secured with suture button through a single transverse incision in high flexion without the need for allograft augmentation. This was a retrospective review of 20 patients with 21 injuries who underwent primary surgical repair of chronic distal biceps tendon avulsions at an average of 10 weeks (range 4-42 weeks). All patients were treated with a single transverse incision with a suture button armed with nonabsorbable no. 2 core sutures. Postoperatively patients were found to have 50°-90° flexion contracture. All patients were placed in a simple sling postoperatively with gentle extension to gravity as tolerated immediately and no formal physical therapy. Patients were surveyed regarding pre- and postoperative American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, visual analog scale (VAS) score, Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and overall satisfaction. Range of motion (ROM), flexion, and supination strength compared to the contralateral uninjured extremity were evaluated at final follow-up. Mean clinical follow-up was 26 months. All patients regained full ROM and 5/5 flexion and supination strength at final follow-up. MEPSs were 100 for all responding patients compared with an average 47.5 preoperatively (P < .0001). The mean postoperative ASES score was 97.2 compared with 41.9 preoperatively (P < .0001). Mean OESs pre- and postoperatively were 24.2 and 48, respectively (P < .0001). The mean VAS score was 4.4 preoperatively and was reported as 0 by all patients at final follow-up (P < .0001). Two patients had transient sensory radial nerve neuropathy, and 1 patient has persistent palsy. No synostoses occurred. Four patients reported supination fatigue postoperatively compared with the uninjured extremity. Given these results, we feel that chronic distal biceps tendon ruptures can be repaired successfully with a single incision using suture button technique without the use of a graft. Though the flexion contracture is significant postoperatively, all patients regained full ROM and had excellent postoperative functional outcome scores.

Reconstruction and repair of atraumatic extensor tendon ruptures in rheumatoid wrists: Less extension lag after direct repair than interposition tendon grafting

The purpose of this study was to investigate the outcomes of extensor tendon repair involving the original stump in atraumatic extensor tendon rupture of rheumatoid wrists. For this study, 16 cases were reviewed involving 14 patients with rheumatoid arthritis. A total of 52 ruptured tendons impacted 36 fingers; 51 tendons were repaired in 35 fingers. The ruptured tendon stumps were repaired either directly by end-to-end suture or by free interposition tendon graft. The 8- to 10-strand core suture method was used for direct repair with a looped 4-0 nylon suture. In all patients, the extensor retinaculum was released and repaired under the tendons. Postoperatively, a volar splint with the wrist and fingers extended was applied for 3 to 4 weeks, followed by a removable splint and gentle active flexion until 6 weeks. The mean follow-up period was 32 months. All fingers recovered active metacarpophalangeal (MCP) joint extension, including independent and active extension of the little finger. Overall, the mean extension lag at the MCP joint was 1.7°. The mean fingertip-to-palm distance with the MCP joint flexed was 0.24mm. The mean extension lag at the MCP joint was significantly greater after interposition tendon grafting (3.2°) than after direct repair (0°). There was no significant difference in the mean fingertip-to-palm distance between direct repair (0.38mm) and interposition tendon grafting (0.13mm). No re-rupture or additional extensor tendon rupture was observed. Repair of the original extensor tendon stump yields satisfactory outcomes and appears to be a viable alternative to tendon transfers in patients with rheumatoid wrists with atraumatic extensor tendon ruptures. Direct repair reduces postoperative extension lag without a significant difference in flexion deficit when compared with interposition tendon grafting.

Influence of Interlocking Horizontal Mattress Epitendinous Suture Placement on Tendinous Biomechanical Properties in a Canine Common Calcaneal Laceration Model.

This article evaluates the effect of an interlocking horizontal mattress epitendinous suture (IHMES) in addition to a three-loop pulley (3LP) core suture for canine tendon repair. Twenty-eight cadaveric common calcaneal tendons were randomized, sharply transected and repaired with either a 3LP or 3LP + IHMES. Tensile loads required to create a 1- and 3-mm gap, yield, peak and failure loads, and mode of failure were analysed. Significance was set at p < 0.05. Mean ± standard deviation yield and failure force for 3LP + IHMES was 178.0 ± 45.3 N and 242.1 ± 47.8 N, respectively, which was significantly greater compared with 3LP alone, 97.9 ± 36.2 N and 119.3 ± 35.6 N (p < 0.0001). Occurrence of 3-mm gap formation was significantly less in the 3LP + IHMES group (p < 0.013). Mode of failure was significantly different between the groups (p < 0.001) with 3LP + IMHES patterns failing by suture breakage (13/14) compared with suture pull-through in the 3LP (11/14). Addition of an epitendinous suture pattern significantly reduced gap formation between tendon ends and significantly increased loads at yield (1.8 × ), peak (2.0 × ) and failure (2.0 × ) force of repairs. Use of an epitendinous suture should be considered to significantly increase biomechanical strength of repairs; however, further in vivo testing is necessary to evaluate its effect on tendinous blood supply.

Delayed (14-30 Days) Percutaneous Repair of Achilles Tendon Ruptures Offers Equally Good Results As Compared With Acute Repair

Background: Minimally invasive repair of acute Achilles tendon ruptures has been performed for several years, resulting in reduced morbidity as compared with open repair. Hypothesis: A minimally invasive technique can be used to manage Achilles tendon ruptures in patients presenting between 14 and 30 days from injury. Study Design: Cohort study; Level of evidence, 3. Methods: We prospectively recruited 21 consecutive patients who presented between 14 and 30 days after the index injury, and we compared them with 21 patients who were matched according to sex, age (±2 years), and level of activity, who presented within 14 days of the index injury. All patients underwent the same minimally invasive procedure under local anesthesia: a core suture repair consisting of a modified Bunnell suture in the proximal stump and a modified Kessler suture in the distal stump. Results: At 12 months after minimally invasive repair, patients with delayed treatment had a median Achilles tendon rupture score of 91 (SD, 2.4; range, 87-96) as compared with 91 (SD, 2.2; range, 86-96) in patients treated acutely, who presented at a median 2.4 days (range 1-6 days) from the injury. There were no significant differences between groups in terms of mean (SD) Achilles tendon resting angle: delayed repair group, −3.9° (2.0); acute repair group, −3.7° (1.9) (P = .69). No patient in either group developed a wound infection. One patient in the acute group experienced an iatrogenic sural nerve injury. Conclusion: Patients with Achilles tendon rupture treated by percutaneous repair 14 to 30 days after injury achieved similar results at 1 year as patient treated <14 after injury.

Primary treatment of flexor tendon injuries

The treatment of flexor tendon injuries is still challenging, especially in the region of the narrow annular ligaments and tendon sheaths of the 3‑segment fingers and the thumb (zone2). In the course of time, the primary suture of the flexor tendons has prevailed over traditional recommendations for asecondary tendon replacement after healing of the wound. Improvements regarding suture techniques and materials and, above all the follow-up treatment, have been crucial for better results and remarkable changes in flexor tendon surgery. The suture techniques are determined by the location of the injury but the experience and preferences of the surgeon are also important. Although no technique was found to be optimal, published research and clinical experiences provide important indications for the presumption of successful treatment. To achieve this an early functionally active protocol should be implemented. The tendon suture should enable this by having ahigh primary strength and therefore at least a4-strand core suture technique with a ring suture should be given preference. Further important prerequisites for success are the undisturbed gliding of the repaired tendon in its "bed" paying special attention to the annular ligaments and preservation of the blood supply to the tendons.

Suture-Based Debris Behavior in the Draining Lymph Nodes of a Porcine Knee: A Study of Silicone, Polyethylene and Carbon

PurposeTo determine whether debris from a silicone core suture has an observable intra-articular or extra-articular impact or can be shown to migrate into the lymphatic system.MethodsUsing a porcine stifle joint model, 2 study groups were created: 1 group used silicone-suture particles created by rupturing hand-tied knots of a nonabsorbable suture with an outer sheath of ultrahigh molecular-weight polyethylene, an inner polyester sheath and a medical-grade silicone/sodium chloride-filled core. The second group used a mixture of 3 vitreous carbon particles sizes. Twelve Yorkshire pigs were randomly assigned to each group. Only 1 type of study particle was used in a single animal to avoid cross-contamination. Half of the study materials were placed by arthrotomy into the joint and, after capsular closure, the remaining half were placed on the joint capsule before skin closure. Six weeks postimplantation, the stifle joints and regional lymph nodes were examined macroscopically and microscopically. The extracapsular and intra-articular tissue and the lymph nodes were examined.ResultsMacroscopically, none of the 12 silicone-suture particle group limbs had abnormal macroscopic observations. Of the 12 limbs in the carbon particle group, 8 demonstrated discoloration in the extracapsular, intra-articular and lymph node tissues; 6 limbs demonstrated joint discoloration (extracapsular and intra-articular). The silicone-suture particle group showed lymph node inflammation in 25% of the iliac lymph nodes and 42% of the inguinal lymph nodes but none in the popliteal lymph nodes. In the carbon particle group, 100% of the iliac lymph nodes, 75% of the inguinal lymph nodes and 8% of the popliteal nodes showed inflammation. No silicone-suture debris migration was observed microscopically. Visible carbon particle migration was present in 100% of the iliac lymph nodes and in 50% of the inguinal lymph nodes but in none (0) of the popliteal lymph nodes. The carbon particle group also showed inflammation in these areas.ConclusionsCarbon particles in the porcine knee migrated into the lymph nodes (iliac 100%; inguinal 50%, popliteal 0); gross discoloration was observed in 8 of 12 specimens. Silicone-suture particles could not be found in the lymph nodes, and no macroscopic joint damage was observed.Clinical RelevanceThe clinical use of a suture containing a silicone/salt central core is common, and the porcine lymphatic model suggests that this type of suture material does not result in clinically significant silicone particulates.

Suture Tape With Broad Full-Width Core Versus Traditional Round Suture With Round Core: A Mechanical Comparison

To compare the inherent mechanical properties of suture in tape configuration with a flat, evenly distributed core to a round suture with a round core composed of the same materials. SutureTape and FiberWire composed of equivalent materials were used to tie surgical knots. Knot height was measured. Knot security was measured at the maximum load at 1, 2, and 3mm of displacement and at failure. Tensile strength and stiffness were measured using untied samples. SutureTape demonstrated superior knot security with greater ultimate load to failure (327.2 ± 15.4N vs 257.4 ± 12.2N; P= .002), maximum load at 1mm of displacement (149.8 ± 18.6N vs 108.8 ± 13.8N; P= .001), and 2mm of displacement (242.7 ± 38.6N vs 181.2 ± 24.4N; P= .008). It also demonstrated greater stiffness (5.4 ± 0.3N/mm vs 2.8 ± 0.3N/mm; P < .001) and tensile strength (378.8 ± 13.6N vs 235.6 ± 4.8N). Knot height differences (1.27 ± .11mm vs 1.37 ± .08mm; P= .110) and load at 3mm of displacement (279.3 ± 42.4N vs 225.5 ± 46.1N; P= .062) were not statistically significant. During mechanical testing, SutureTape with a broad core distributed over the full width of the tape demonstrated greater knot security, ultimate load to failure, and tensile stiffness than FiberWire, a round core suture. We found no significant difference in knot stack height between the suture designs. The study demonstrates the superior mechanical properties of suture in tape configuration over similarly composed round suture without a significant difference in knot stack height. Suture in tape configuration has the potential to perform as well as round suture in the clinical setting.

Effect of a continuous epitendinous suture as adjunct to three-loop pulley and locking-loop patterns for flexor tendon repair in a canine model.

To evaluate the effect of combining a continuous epitendinous suture with three-loop pulley (3LP) and locking-loop (LL) core patterns for flexor tendon repair. Ex vivo biomechanical study. Seventy-two cadaveric superficial digital flexor musculotendon (SDFT) units. Tendons were divided into four groups (n = 18/group). After sharp transection, SDFT were repaired with 3LP, LL, 3LP + epitendinous (E), or LL + E suture patterns. After preloading, repaired constructs were tested to failure. Video data acquisition allowed evaluation of failure mode and quantitation of gap formation. Yield, peak, and failure force were measured from force-displacement data. Significance was set at P < .05. Mode of failure did not differ between repairs with or without an epitendinous suture (P = .255). Gap formation was best prevented with 3LP compared with LL when used alone (P = .001). Mean yield force for 3LP, LL, 3LP + E, and LL + E were 91.4 N ± 25.4, 61.3 N ± 18.4, 195.2 N ± 66.0, 165.3 N ± 46.8, respectively. Tenorrhaphies combined with an epitendinous suture achieved higher yield (P < .0001), peak (P < .0001), and failure forces (P < .0001), without gapping between tendon ends. Addition of an epitendinous suture eliminated gapping between tendon ends until failure and increased resistance to loads tolerated at the repair site. The addition of an epitendinous suture may increase the strength of tendon repairs and resistance to gap formation over core suture use alone. The influence of epitendinous suture placement on tendinous healing and blood supply warrants in-vivo testing.