Flexor Tendon Grafts Research Articles

Two-Stage Flexor Tendon Reconstruction for Finger Contracture Secondary to Phlegmon: A Case Report

Flexor tendon reconstruction is a complex surgical procedure that requires great precision and specialized expertise. It remains a preferred treatment for patients with neglected lacerations of the digital flexor tendon and after the failure of flexor tendon repair. Improvements in tendon repair methods and follow-up techniques have enhanced outcomes after flexor tendon grafting. Case Presentation: A 14-year-old girl with a history of a phlegmon of the 4th finger of the right hand, treated with antibiotics and drainage. The evolution is marked after 2 years by the progressive development of a flexion contracture of the proximal interphalangeal (PIP) joint. On examination, there is a flexion attitude and an inability to extend the PIP joint without vascular or nervous disorders. A two-stage reconstruction was performed using the palmaris longus tendon as a graft. With a follow-up of 3 years, the girl has recovered complete flexion and has limited extension to 25° at the PIP joint. An arthrolysis was proposed, but the girl refused, and she is satisfied with the results.

Flexor Tendon Grafting as Reoperative Procedure for Injuries within Fingers and Thumb

Background. The reoperation rate reported in the literature in cases of flexor tendon injuries within the fingers and thumb is about 20%, but the functional results of these reoperations are barely discussed.
 The aim of the study was to evaluate the results of flexor tendon grafting performed as a redo procedure in patients who had previously underwent unsuccessful flexor tendon surgery.
 Methods. This study reports the outcomes of deep flexor tendon and flexor pollicis longus tendon grafting in 122 fingers of 109 patients depending on two factors — the type of the first failed surgery (tendon suture in 51 fingers vs grafting in 71 fingers) and the type of the medical unit where the failed procedure had been performed (hand surgery department in 76 cases vs general trauma unit in 46 cases).
 Results. Our reoperative grafting procedures led to excellent results in 13 fingers of 51 (25.5% [95% CI: 14–40]) after failed tendon suture and in 32 fingers of 71 (45.1% [95% CI: 33–57]) after failed previous grafting, difference is statistically significant (÷2 = 4.888; p = 0.027). Failed surgeries performed at the hand surgery departments were redone with 48.7% [95% CI: 37–60] of excellent results (in 37 fingers of 76) and 14.5% [95% CI: 7–24] of fair results (in 11 fingers of 76). Failed surgeries performed at the general trauma units were redone with 17.4% [95% CI: 8–31] of excellent results (in 8 fingers of 46). This value statistically significantly differed from the hand surgery departments group: ÷2 = 12.054; p = 0.001. For a total, excellent results were obtained in 36.9% [95% CI: 28–46] (in 45 fingers of 122) of reoperative grafting procedures and good results in 34.5% [95% CI: 26–43] (in 42 fingers of 122).
 Conclusions. Analysis of the functional results of deep flexor tendon and flexor pollicis longus tendon grafting performed as a reoperative procedure showed that the excellent results with full finger function were achievable in patients who had previously undergone unsuccessful flexor tendon surgery in zone 2. But in general, the rates of motion recovery were significantly lower than in uncomplicated cases, even with a long history of injury. The worst functional results of reoperations were in patients who had previously been unsuccessfully operated in non-specialized medical units.

The Bone Bridge for Tibial ACL Graft Fixation: A Biomechanical Analysis of Different Tibial Fixation Methods for ACL Reconstruction.

The tibial fixation site is considered the weak link in anterior cruciate ligament (ACL) reconstruction, and conflicting results regarding the biomechanical properties of various fixation methods have been reported. To examine knots tied over a bone bridge and its biomechanical properties as a suitable tibial fixation method in ACL reconstruction. Controlled laboratory study. We divided 40 fresh-frozen porcine tibiae into 4 equal groups to evaluate flexor tendon grafts set with standard tibial fixation techniques: (1) bone bridge (BB group), (2) suspension button (SB group), (3) combined interference screw and bone bridge (IFS/BB group), and (4) combined interference screw and suspension button (IFS/SB group). Each construct was subjected to cyclic loading (1500 cycles, 50-250 N, 1 Hz) with a servohydraulic materials testing machine to measure elongation; load-to-failure testing (displacement rate: 25 mm/s) was then performed. Load to failure, stiffness, and yield load were compared between constructs using 1-way analysis of variance. The hybrid fixation constructs (IFS/BB and IFS/SB groups) showed significantly better biomechanical properties than the isolated extracortical fixation constructs (BB and SB groups) (P < .05 for all). There were no differences between the isolated extracortical fixation constructs or between the hybrid fixation constructs in elongation or load to failure; however, stiffness of the IFS/BB group was significantly higher than that of the IFS/SB group (175.3 ± 16.6 vs 144.9 ± 20.1 N/mm, respectively; P < .05). Stiffness between the SB and BB groups was not significantly different. Hybrid fixation had superior biomechanical performance compared with isolated extracortical fixation. However, tibial graft fixation using a bone bridge either as isolated extracortical fixation or combined with an interference screw for hybrid fixation showed equivalent biomechanical properties compared with suspension button-based graft fixation. The clinical use of a bone bridge for tibial graft fixation could reduce the cost for ACL reconstruction and lower the rate of implant-associated issues.

Superficial digital flexor tendon graft augmentation improves the tensile strength and resistance to gap formation following primary gastrocnemius tendon repair in dogs.

To evaluate the influence of superficial digital flexor tendon (SDFT) graft augmentation on the biomechanical properties and resistance to gap formation in a canine gastrocnemius tendon repair model. 28 canine cadaveric hind limbs. Respective hindlimbs from each dog were randomized to one of two groups (n = 14/group) using a 3-loop-pulley (3LP) pattern alone or 3LP + SDFT graft augmentation. Biomechanical parameters evaluated included yield, peak, and failure loads; tensile loads required to create 1- and 3-mm gap formations; and mode of construct failure. Mean yield and failure loads for the 3LP + SDFT graft group were 483.6 ± 148.0 N and 478.3 ± 147.9 N, respectively, and were greater compared to the 3LP group (34.2 ± 6.7 N and 34.0 ± 8.0 N, P < .0001). Loads to both 1- and 3-mm gap formations for the 3LP + SDFT graft group were greater compared to 3LP alone (P < .001). Failure modes did not differ between groups (P = .120), with constructs failing most commonly by suture pulling through opposed tendinous tissues whereas SDFT grafts remained intact. SDFT graft augmentation increased yield, peak, and failure forces 14-fold across all examined biomechanical variables compared to the 3LP group. The 3LP + SDFT graft group required 3.6X and 6.5X greater loads to cause a 1- and 3-mm gap, respectively, between tendon ends. These data support the biomechanical advantages of SDFT graft augmentation to increase repair-site strength and to promote resistance to gap formation of the tenorrhaphy. Additional in vivo studies are required to determine the effect of SDFT augmentation on clinical function and active limb use after graft harvest in dogs.

Secondary Procedures following Flexor Tendon Reconstruction.

After studying this article, the participant should be able to: 1. Understand the indications and management options for secondary flexor tendon reconstruction, including tenolysis, tendon grafting, and tendon transfers. 2. Understand the reconstructive options for pulley reconstruction. 3. Understand the options for management of isolated flexor digitorum profundus injuries. Despite current advances in flexor tendon repair, complications can still occur following surgery. This article presents the spectrum of treatment options for secondary flexor tendon reconstruction ranging from tenolysis to one- and two-stage tendon grafting, and tendon transfers. In addition, an overview of pulley reconstruction and the treatment of isolated flexor digitorum profundus injuries are discussed. A management algorithm for secondary flexor tendon reconstruction is provided.

Outcomes of staged reconstruction of Zone 2 flexor tendon injuries in recent wide-awake surgical settings and an earlier case series

We report outcomes of patients who were managed with two-stage tendon grafting for neglected Zone 2 flexor tendon injuries from 2012 until 2019. The patients were divided into two cohorts: recent series (Series 1) included patients treated with local anaesthesia and epinephrine (16 fingers, from 2015), and earlier series (Series 2) included patients treated with either general or local intravenous anaesthesia and tourniquet (12 fingers, before 2015). The patients in Series 1 achieved statistically better mean total active motion of the operated fingers and grip compared with the contralateral hand than the earlier series (p = 0.03, p = 0.01, respectively). With the Tang grading system, excellent and good results were achieved in 13 and six fingers of the patients in Series 1 and Series 2, respectively. We conclude that wide-awake second stage of staged flexor tendon grafting provides fine-tuned adjustment of length and tension of the graft, but we cannot conclude about comparative outcomes between two series because the sample size is small and the earlier series was operated by the same surgeons with lower expertise level.Level of evidence: IV.

ОТДАЛЕННЫЕ РЕЗУЛЬТАТЫ ВОЗВРАТНОГО ЧРЕСКОСТНОГО ШВА СУХОЖИЛИЙ СГИБАТЕЛЕЙ ПАЛЬЦЕВ КИСТИ К ДИСТАЛЬНОЙ ФАЛАНГЕ

Aim: To analyze results of proposed reverse transosal suture. Materials: 264 cases (187 patients; 143 men, 44 women, age between 5 to 75 y. o.) of tendon fixation to distal phalanx by proposed technique was accepted in our research, after two stages flexor tendon grafting, in 2008—2019. On 2nd day after surgery - early full amplitude movement rehabilitation protocol (modification of Kleinart technique) was applied. Results: In an interim analysis of 109 patients treatment results, we noted complications associated with a transossal tendon suture to distal phalanx in 7.5 % (8/159) of cases: infectious complication — 1 case, serious nail growth disorders — 1, slight deformation of the nail plate — 5 cases, periodic pain in distant period — 1 case. To avoid complications associated with nail plate disorders, suture technique was modified by displacing the transcutaneous canal to the side of the nail germinal zone without incision on the back of the finger. No deformation of the nail plate was observed after changing of suture technique. Conclusions: flexor digitorum profundus tendon fixation technique minimizes trauma to surrounding tissues. Strong internal fixation of the tendon gives the possibility of early movements. Intermediate material analysis made it possible to change the suture technique to effectively eliminate the most common complications.

Differentially Expressed Proteins in Intra Synovial Compared to Extra Synovial Flexor Tendon Grafts in a Rabbit Tendon Transplantation Model.

Uncomplicated healing of grafts for tendon reconstruction remains an unsolved problem in hand surgery. Results are limited by adhesion formation and decreased strength properties, especially within the tight fibro-osseous sheath of the digits. This is especially problematic when an extra synovial tendon graft is used to replace an intra synovial flexor tendon. Compositional differences are likely to play an important role in these processes. The aim of this study was, therefore, to compare protein expression in pair-matched intra synovial tendon grafts with extra synovial tendon grafts, using a rabbit tendon injury model. We hypothesized that there would be significant differences in proteins critical for response to tensile loading and adhesion formation between the two groups. Using mass spectrometry and multivariate statistical data analysis, we found tissue-specific differences in 22 proteins, where 7 explained 93% (R2) of the variation, with a prediction of 81% (Q2). Among the highest discriminating proteins were Galectin, Histone H2A, and Periostin, which were found in a substantially larger amount in the extra synovial tendons compared to the intra synovial tendons. These findings may contribute to improved understanding of the differences in outcome seen after tendon reconstruction using tendon grafts with intra synovial and extra synovial grafts.

Flexor tendon grafts for pulley reconstruction – Morphological aspects

BackgroundPulleys are crucial to convert flexor tendon excursion into angular motion at the metacarpophalangeal and interphalangeal joints. Loss of pulley function can lead to significant impairment of hand function and may require surgical reconstruction. This reconstruction can be achieved using different flexor tendons grafts, such as the intrasynovial flexor digitorum superficialis (FDS) or the extrasynovial palmaris longus (PL). However, there is limited knowledge on the micromorphology of human pulleys and the suitability of flexor tendon grafts for their reconstruction remains elusive. MethodsIn the present cadaver study A2 and A4 pulleys were compared with FDS and PL tendons by means of scanning electron microscopy (SEM), histology and immunohistochemistry. Surface morphology, core structure and vascularization of the specimens were analyzed. ResultsSEM imaging of the gliding surfaces revealed morphological differences between tendons and pulleys. Moreover, the core structure of FDS samples was characterized by bundles of individual collagen fibrils whereas PL tendons exhibited a less hierarchical microstructure. In contrast, pulleys consisted of lamellar sheets of densely packed collagen fibrils. Finally, immunohistochemical analyses revealed that the flexor tendons and pulleys contain similar numbers of CD31+ microvessels, indicating a comparable tissue vascularization. ConclusionThis study provides novel SEM and immunohistochemical insights into the micromorphology of human pulleys and flexor tendon grafts. Intrasynovial flexor tendons may be particularly suitable for pulley reconstruction and preserving the paratenon may be crucial for graft revascularization.

Significant Loss of ACL Graft Force With Tibial-Sided Soft Tissue Interference Screw Fixation Over 24 Hours: A Biomechanical Study.

Background:Tibial-sided graft fixation is thought to be critical for the success of anterior cruciate ligament (ACL) reconstruction. Nevertheless, little is known about the graft force after fixation during the first 24 hours after surgery or the influence of screw diameter and length during this time.Purpose:To investigate the force, over the course of 24 hours, in soft tissue grafts secured with a tibial interference screw and to evaluate the effect of different screw diameters (7, 8, and 9 mm) and lengths (25 and 30 mm) on the force in these grafts.Study Design:Controlled laboratory study.Methods:Quadruple-strand flexor tendon grafts were fixed with bioabsorbable interference screws in 60 porcine tibiae. Grafts were pretensioned at 80 N over 10 minutes, and screws were inserted outside-in while a preload force of 80 N was applied. Different screw lengths (25 and 30 mm) and diameters (7, 8, and 9 mm), resulting in 6 groups with 10 specimens each, were tested. After release of the preload, graft force was recorded over 24 hours.Results:A significant decrease in graft force progressed in all groups over the 24-hour period. In total, a median loss of 75 N (IQR, 68-79 N) compared with the initial loading force was observed. Compared with the loading force of 80 N, this corresponded to a median loss of 91%. No significant differences in the remaining graft force could be found among the 6 different screw length and diameter groups after 10 minutes, 100 minutes, or 24 hours.Conclusion:Graft force in soft tissue grafts secured with a tibial interference screw decreased substantially over the first 24 hours after fixation. Neither the screw diameter nor the screw length affected the decrease in graft force. This raises substantial questions regarding the remaining fixation strength in vivo.Clinical Relevance:It should not be expected that ACL reconstruction can mechanically restabilize an injured knee as would an intact ACL. Reconstructed knees should be protected from mechanical overload in the early postoperative period.

Flexor Tendon Grafting Using Extrasynovial Tendons Followed by Early Active Mobilization

PurposeThis study evaluated the outcomes of early active mobilization after flexor tendon grafts using extrasynovial tendons with a novel distal fixation technique.MethodsThis study was a retrospective case series. The flexor digitorum profundus (FDP) tendons of 7 digits in 7 patients were reconstructed with extrasynovial tendons, which included the palmaris longs, plantaris, and extensor digitorum longus, in a single- or 2-stage procedure between 2008 and 2017. Of the 7 patients, 6 were male and the average patient age was 48 years. The injuries involved 2 middle, 2 ring, and 3 little fingers. The tendons were sutured into the appropriate FDP tendon proximally using end-weave anastomosis; the distal end of the graft was fixed to the distal stump of the FDP using an interlacing suture or a small bone anchor combined with the pull-through technique. The digits were mobilized with a combination of active extension and passive and active flexion in a protective orthosis during the first 6 weeks after surgery. Average follow-up was 18 months. We measured active and passive digit motion both before tendon grafting and at the final evaluation. Outcomes were graded by the LaSalle formula to assess staged flexor tendon reconstruction.ResultsAverage passive range of motion (ROM) of the proximal and distal interphalangeal joints before flexor tendon grafting was 146° (SD, 22°). Mean active ROM of these joints at the final evaluation was 123° (SD, 34°). Using the LaSalle formula, mean recovery of active motion was 83%. We encountered no grafted tendon rupture and no finger required tenolysis.ConclusionsOur proximal and distal fixation techniques allowed the autologous extrasynovial tendon grafts to withstand the stress encountered during early active mobilization with good postoperative ROM and minimal complications.Type of study/level of evidenceTherapeutic I.

Results of flexor tendon grafting with early active mobilization

Objective The aim was to evaluate the results of early active motion regimen after hand flexor tendon grafting. Background The application of proper postoperative rehabilitation program is an integral part to achieve good results after hand flexor tendon grafting. The aim of application of early, active mobilization rehabilitation program is to limit adhesion formation which limits active motion. Patients and methods Twenty-three fingers were managed by flexor tendon grafting and assessed from February 2015 till August 2016 at Menoufia University Hospital. In all, 17 fingers had two stages tendon grafting and six fingers had single-stage tendon grafting. Early active mobilization rehabilitation regimen was applied for all patients. Postoperative assessment was done by the American Society for Surgery of the Hand system, Strickland system, Buck-Gramcko method, and LaSalle formula. Results Final assessment was done at 6 months postoperatively and the results were as follows: good (52.17%), fair (39.13%), and poor (8.7%) according to the American Society for Surgery of the Hand system. According to the Strickland system, the results were excellent (13.04%), good (34.78%), fair (39.13%) and poor (13.04%). According to the Buck-Gramcko score, the results were excellent (21.7%), very good (17.4%), good (39.1%) good, fair (8.7%), and poor. (13.1%) According to LaSalle formula, the results were excellent (34.78%), good (52.17%), fair (8.7%), and poor (4.4%). Complications were adhesion formation (8.7%), infection (8.7%), flexor pulley rupture (4.3%), graft rupture (4.3%), and tourniquet palsy (4.3%). Conclusion The results were found to be affected by sex, dominance of affected hand, affected tendon(s), flexor pulley integrity, type of procedure, and by the type of tendon graft.

Kinetic analysis of canine gait on the effect of failure tendon repair and tendon graft

Kinetic analysis of canine gait has been extensively studied, including normal and abnormal gait. However, no research has looked into how flexor tendon injury and further treatment would affect the walking pattern comparing to the uninjured state. Therefore, this study was aimed to utilize a portable pressure walkway system, which has been commonly used for pedobarographic and kinetic analysis in the veterinary field, to examine the effect of a failed tendon repair and tendon graft reconstruction on canine digit kinetics during gait. 12 mixed breed (mongrel) hound-type female dogs were included in this study and 2nd and 5th digits were chosen to undergo flexor tendon repair and graft surgeries. Kinetic parameters from the surgery leg in stance phase were calculated. From the results, after tendon failure repair, decrease of weight bearing was seen in the affected digits and weight bearing was shifted to the metacarpal pad. After tendon graft reconstruction, weight bearing returned to the affected digits and metacarpal pads. Slight alteration in peak pressure and instant of peak force were identified, but it was estimated to have little influence on post-reconstruction gait. This study could serve as a reference in evaluating canine digit function in flexor tendon injury for future studies.

Anterior Cruciate Ligament Soft Tissue Graft Fixation in the Elderly: Is There a Reason to Use Interference Screws? A Human Cadaver Study

To analyze the ultimate failure load, yield load, stiffness, and cyclic resistance of different anterior cruciate ligament (ACL) soft tissue graft fixation techniques in osteopenic bone. In this study, 24 fresh-frozen human cadaveric tibiae (mean age 82.6years; range 56-96; 6 male and 6 female donors) were used. Quantitative computed tomography was performed to match bone density. Looped porcine flexor tendon grafts were chosen as ACL graft substitutes for tibial graft fixation techniques (n= 8 each): (1) hybrid fixation with an interference screw and extracortical button fixation; (2) extracortical button fixation; and (3) interference screw fixation. In single cycle mode, constructs were loaded to failure to evaluate stiffness, yield load, and maximum load. In cyclic testing, 2,000 cycles (25-100N) were applied followed by loading to failure. A 1-way analysis of variance was performed with significance set at P= .05. Hybrid fixation resulted in significantly higher yield load (283.4 ± 86.19N; P= .0037) and maximum load (407.9 ± 102.3N; P= .0026) than interference screw fixation (yield load 176.4 ± 26.03, max load 231.8 ± 94.06N) in elderly bone. Yield load after extracortical button fixation (252.9 ± 41.97N; P= .0286) was also higher than that after interference screw fixation, but stiffness (18.98 ± 9.154N/mm; P= .0041) was less than that after hybrid fixation (37.28± 13.53N/mm). Of 8 specimens in the interference screw group, 7 did not survive 2,000 cycles and failed by graft slippage, whereas all other specimens in both other groups survived. Tibial hybrid fixation of ACL soft tissue grafts provides less vertical graft movement than extracortical button fixation and higher primary failure loads than interference screw fixation in elderly bone. In this elderly human joint invitro model, tibial hybrid fixation provides biomechanical advantages over other techniques. Graft fixation with only an interference screw should be avoided in osteopenic bone.

The influence of femoral tunnel length on graft rupture after anterior cruciate ligament reconstruction

BackgroundFor ACL reconstruction, the minimum length of the femoral tunnel and the flexor tendon graft length needed within the tunnel for proper integration have not been defined. The aim of this study was to assess whether a short tunnel is a risk factor for poor prognosis and re-rupture by comparing the outcomes of patients with short femoral tunnels to those of patients with longer tunnels.Materials and methodsA retrospective observational study of 80 patients who underwent ACL reconstruction using flexor tendons via the medial transportal or transtibial technique was performed. Patients were categorized according to the amount of graft within the tunnel: ≤1.5 versus >1.5 cm; ≤2 versus >2 cm; ≤2.5 versus >2.5 cm; and ≤1.5 versus >2.5 cm. Patients were evaluated 2 years after surgery by performing a physical examination (Lachman, pivot shift and anterior drawer tests), using a KT1000 arthrometer, calculating objective and subjective International Knee Documentation Committee scores, conducting the Lysholm score, and recording re-ruptures.ResultsOf the 80 operated patients, nine were lost to follow-up. Comparative assessment of the patients with different amounts of graft within the tunnel indicated no significant differences in the evaluated outcomes, except for positive Lachman test results, which were more frequent in patients with tunnels with ≤2 cm of graft than in those with tunnels with >2 cm of graft.ConclusionThe amount of graft within the femoral tunnel does not appear to be a risk factor for clinical instability of the knee or re-rupture of the graft. Level of evidence: case series, level IV. Level of evidenceCase series, level IV.

Prediction of flexor tendon graft diameter in reconstruction of the anterior cruciate ligament by means of magnetic resonance imaging

ObjectiveTo evaluate the diameter of the flexor tendons in preoperative magnetic resonance imaging (MRI) examinations and compare this with the diameter of the graft obtained intraoperatively. MethodsThis was a retrospective longitudinal epidemiological study. Forty-four patients were eligible for the study and their MRI examinations and surgical data were evaluated. The tendons were measured on MRI across their largest diameter in the axial plane, using the medial epicondyle of the femur as the slice level. In the surgery, routine graft preparation was performed, consisting of folding the gracilis and semitendinosus tendons to form a four-strand graft. Its measurement was recorded. ResultsTo evaluate the association between the variables, Pearson's correlation coefficient was estimated. A significant correlation was found between the measurements of the gracilis and semitendinosus tendons and the final diameter of the graft (p<0.001). A ROC curve was fitted to the sum of the tendon diameters in order to determine a cutoff point associated with the graft diameter (≤8mm or >8mm). If the sum was greater than 5.28mm, the chance of obtaining a graft larger than 8mm would be 75%. ConclusionMeasurement of the diameters of the gracilis and semitendinosus tendons through a preoperative MRI examination is a simple and effective way to predict the final size of the graft to be used in ACL reconstruction surgery.

Effect of carbodiimide-derivatized hyaluronic acid gelatin on preventing postsurgical intra-abdominal adhesion formation and promoting healing in a rat model.

Adhesions often occur after abdominal surgery. It could cause chronic pelvic pain, intestinal obstruction, and infertility. A hydrogel biomaterial, carbodiimide-derivatized hyaluronic acid gelatin (cd-HA gelatin), has been successfully used to reduce adhesion formation after flexor tendon grafting. This study investigated the efficacy of cd-HA gelatin in preventing postsurgical peritoneal adhesions in a rat model. The surgical traumas were created on the underlying muscle of the abdominal wall and the serosal layer of the cecum. The wounds were covered with or without cd-HA gelatin. Animals were euthanized at day 14 after surgery. Adhesion formation was assessed with adhesion degree and adhesion breaking strength. The healing of abdominal wall was evaluated with biomechanical testing and histological analysis. The adhesions occurred in all rats (n = 12) without cd-HA gelatin treatment. The application of cd-HA gelatin significantly reduced the adhesion rate from 100% to 58%. The decrease of adhesion breaking strength also manifested that cd-HA gelatin could reduce postsurgical intra-abdominal adhesion formation. Moreover, it was found that cd-HA gelatin was a safe material and could promote tissue healing. The cd-HA gelatin hydrogel could reduce the formation of intra-abdominal adhesions without adversely effects on wound healing.

Indian hedgehog signaling and the role of graft tension in tendon-to-bone healing: Evaluation in a rat ACL reconstruction model.

The structure and composition of the native enthesis is not recapitulated following tendon-to-bone repair. Indian Hedgehog (IHH) signaling has recently been shown to be important in enthesis development in a mouse model but no studies have evaluated IHH signaling in a healing model. Fourteen adult male rats underwent ACL reconstruction using a flexor tendon graft. Rats were assigned to two groups based on whether or not they received 0N or 10N of pre-tension of the graft. Specimens were evaluated at 3 and 6 weeks post-operatively using immunohistochemistry for three different protein markers of IHH signaling. Quantitative analysis of staining area and intensity using custom software demonstrated that IHH signaling was active in interface tissue formed at the healing tendon-bone interface. We also found increased staining area and intensity of IHH signaling proteins at 3 weeks in animals that received a pre-tensioned tendon graft. No significant differences were seen between the 3-week and 6-week time points. Our data suggests that the IHH signaling pathway is active during the tendon-bone healing process and appears to be mechanosensitive, as pre-tensioning of the graft at the time of surgery resulted in increased IHH signaling at three weeks.

Biomechanical Evaluation of Flexor Tendon Graft with Different Repair Techniques and Graft Surface Modification: N/A - Not a clinical study

Biomechanical Evaluation of Flexor Tendon Graft with Different Repair Techniques and Graft Surface Modification: N/A - Not a clinical study

Effect of cyclic tension on the biomechanical properties of flexor tendon grafts. Results of an ex-vivo porcine study.

Autologous flexor tendons are widely used for anterior cruciate ligament (ACL) reconstruction. Pretension of the graft before fixation has been described as part of the surgical technique, nevertheless there is no consensus on the type and amount to tension needed to increase the stiffness without affecting its biomechanical properties.Our hypothesis is cyclic tension increases flexor tendon stiffness without affecting its ultimate failure at maximum loads (UFML). Forty-five flexor digitorum profundus tendons harvested from domestic pigs (Sus scrofa domestica) were randomly divided into three groups: E1 (n=15), E2 (n=15) and C (n=15). Groups E1 and E2 were subjected to 50 cyclic loads at a 1 Hz frequency, at 70N and 100N respectively, group C was not intervened. The three groups were then tested for UFML. Cyclic loads and measurements were performed using a Stress-Strain machine (SST 1.0 Kinetecnic). Results were analyzed using GrapgPad statistical software. Groups were compared using Mann-Whitney test with a 95% confidence interval. Significant increased stiffness for group E1 (p=0.02) and group E2 ( p<0.01) when compared to group C. The stiffness of group E2 was also significantly higher than E1 (p=0.03). There was a significant reduction on the UFML between group E2 and C (p<0.01), which was not observed when comparing groups E1 and C. Cyclic loads at 70N result in an increased stiffness of flexor tendons without affecting its ultimate failure at maximum loads. Cyclic loads at higher tensions might cause a deleterious effect on the biomechanical properties of flexor tendon grafts.