Aims. The effects of remnant preservation on the anterior cruciate ligament (ACL) and its relationship with the tendon graft remain unclear. We hypothesized that the co-culture of remnant cells and bone marrow stromal cells (BMSCs) decreases apoptosis and enhances the activity of the hamstring tendons and tenocytes, thus aiding ACL reconstruction. Methods. The ACL remnant, bone marrow, and hamstring tendons were surgically harvested from rabbits. The apoptosis rate, cell proliferation, and expression of types I and III collagen, transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF), and tenogenic genes (scleraxis (SCX), tenascin C (TNC), and tenomodulin (TNMD)) of the hamstring tendons were compared between the co-culture medium (ACL remnant cells (ACLRCs) and BMSCs co-culture) and control medium (BMSCs-only culture). We also evaluated the apoptosis, cell proliferation, migration, and gene expression of hamstring tenocytes with exposure to co-culture and control media. Results. Compared to BMSCs-only culture medium, the co-culture medium showed substantially decreased early and late apoptosis rates, attenuation of intrinsic and extrinsic apoptotic pathways, and enhanced proliferation of the hamstring tendons and tenocytes. In addition, the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes in the hamstring tendons and tenocytes significantly increased in the co-culture medium compared to that in the control medium. Conclusion. In the presence of ACLRCs and BMSCs, the hamstring tendons and tenocytes significantly attenuated apoptosis and enhanced the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes. This in vitro study suggests that the ACLRCs mixed with BMSCs could aid regeneration of the hamstring tendon graft during ACL reconstruction. Cite this article: Bone Joint Res 2023;12(1):9–21

Aims. The traditional transosseus flexor hallucis longus (FHL) tendon transfer for patients with Achilles tendinopathy requires two incisions to harvest a long tendon graft. The use of a bio-tenodesis screw enables a short graft to be used and is less invasive, but lacks supporting evidence about its biomechanical behaviour. We aimed, in this study, to compare the strength of the traditional transosseus tendon-to-tendon fixation with tendon-to-bone fixation using a tenodesis screw, in cyclical loading and ultimate load testing. Materials and Methods. Tendon grafts were undertaken in 24 paired lower-leg specimens and randomly assigned in two groups using fixation with a transosseus suture (suture group) or a tenodesis screw (screw group). The biomechanical behaviour was evaluated using cyclical and ultimate loading tests. The Student’s t-test was performed to assess statistically significant differences in bone mineral density (BMD), displacement, the slope of the load-displacement curves, and load to failure. Results. The screw group showed less displacement (loosening) during cyclical loading, which was significant during 300, 500, 600, 700, 800, 900, and 1000 cycles (p < 0.05: other cycles: 0.079 < p < 0.402). Compared with the suture group, the screw group had higher mean ultimate load values (133.6 N, . sd. 73.5 vs 110.1 N,. sd. 46.2; p = 0.416). Conclusion. Fixation of the FHL tendon with a tenodesis screw enables a less invasive procedure to be undertaken and shows similar biomechanical behaviour and primary strength compared with fixation using a transosseus suture. Cite this article: Bone Joint J 2018;100-B:1175–81

The excursion resistance between the tendon and pulley is an important factor contributing to the limitation of function after surgery to the hand. The administration of hyaluronic acid (HA) in the early rehabilitation after tendon grafting may help to prevent adhesions. We evaluated changes in the excursion resistance between potential sources of flexor tendon grafts and the annular pulley in a canine model after administration of HA. The intrasynovial and extrasynovial tendons were soaked in 10 mg/ml of HA for five minutes. The excursion resistance between these tendons and the annular pulley of an intact proximal phalanx and that of the same tendons of the opposite foot without administration of HA were evaluated. The tendon of flexor digitorum profundus of the second toe without administration of HA was used as a control. The gliding resistance of canine tendons was significantly decreased after the administration of HA especially in the extrasynovial tendons. Our findings suggest that the administration of HA may improve the gliding function of a flexor tendon graft

Bone-patellar tendon-bone autografts, hamstring autografts or allografts are widely used grafts for ACL revision surgeries. Also use of quadriceps autograft for both primary and revision ACL surgeries is in an increasing popularity due to its biomechanical superior properties and less donor site morbidity. However, although several fixation techniques and devices for quadriceps tendon graft fixation on femoral side have been reported, literature lacks about biomechanical studies comparing properties of these different fixation techniques and devices. We aimed to investigate whether there is a difference between the fixation techniques of quadriceps tendon graft by using different fixation techniques and devices on the femoral side in terms of stiffness and amount of slippage in the tunnel. Full-thickness central parts of quadriceps tendons from paired knees of twenty five calf knees were fixed through a 10mm x 25mm tunnel in twenty five paired sheep femurs. Quadriceps tendon patellar side with soft tissue ending fixed with four different fixation devices (adjustable suspensory system (group 1), absorbable interference screw (group 2), titanium interference screw (group 3) and adjustable suspensory system + absorbable interference screw (group 4)) and quadriceps tendon with a patellar bone plug fixed with a titanium interference screw (group 5) were tested in a servohydraulic materials testing machine. 10 samples were included in each group. After applying a preload of 10 N, a cyclic force was applied for 20 cycles from 10N to 110N at a 1 hertz frequency. Amount of slippage in the tunnel was calculated as the difference measured in millimeters between length at 10 N after 20 cycles and starting length at 10 N (Graph 1). To determine the stiffness, a single load-to-failure cycle was performed at a strain rate of 20 mm/min as the last step (Figure 1). Rupture of the graft was not seen in any of the samples. Median values of amount of slippage in the tunnel were 6,41mm, 5,99mm, 3,01mm, 4,83mm, and 3,94mm respectively. Median values of maximum load at failure were 464N, 160N, 350N, 350N and 389N respectively. Amount of slippage in the tunnel was highest in the group 1 and was lowest in the group 3 (p<0.001). Group 1 was found to be most resistant group against load-to-failure test and group 2 was the weakest (p<0.001). However inter-group analyses between group 3 and 5 revealed that, although group 3 had the least slippage in the tunnel, group 5 was better in terms of stiffness, but there was no statistically significant difference (p=0,124 and 0,119 respectively). There was a significant difference between group 2 and 3 in both amount of slippage in the tunnel and stiffness (p=0,001 and 0.028 respectively)(Table 1). Our study revealed that, although quadriceps graft with a bone plug fixed with metal interference screws is widely presumed to be a stable fixation technique, there was no significant difference in terms of stiffness when compared with quadriceps graft with soft tissue ending fixed with a metal interference screw. Although adjustable suspensory device group was the best in the terms of resistance against load-to-failure, it was the worst in terms of amount of slippage from the tunnel. Thus, if a suspensory device is to be used, it must be kept in mind that a strong 20 cycles of intra-operative tension force must be applied to prevent further slippage of the graft in the tunnel which can result in failure of reconstruction. For any figures or tables, please contact the authors directly

This is largest collection of outcomes of distal biceps reconstruction in the literature. 8 subjects prospectively measured pre and post reconstruction Strength deficit in patients with chronic tendon deficit is described. To describe outcomes for 53 chronic distal biceps reconstructions with tendon graft. Clinical outcomes as well as strength and endurance in supination and flexion are reported. To examine eight patients measured pre- and post-reconstruction. To identify deficit in supination and flexion in chronic reconstruction. 53 reconstructions of chronic distal biceps with tendon graft were carried out between 1999 and 2015. 26 subjects agreed to undergo strength testing after minimum one year follow up. Eight subjects were tested both before and after reconstruction. Primary outcomes were strength in elbow flexion and forearm supination. Strength testing of supination and flexion included maximum isokinetic power and endurance performed on a Biodex. Clinical outcomes measures included pre-operative retraction severity, surgical fixation technique, postoperative contour, range of motion, subjective satisfaction, SF-12, DASH, MAYO elbow score, ASES and pain VAS Non-parametric data was reported as median (interquartile range), while normally-distributed data was reported as mean with 95% Confidence Limits. Hypothesis testing was performed according to two-tailed, paired t-tests. Median time from index rupture to reconstructions 9.5 (range 3–108) months. Strength measurements were completed at a median follow-up time of 29 (range 12–137) months on 26 subjects. The proportion of patients that achieved 90% strength of the contralateral limb post-reconstruction was 65% (17/26) for peak supination torque, and 62% (16/26) for peak flexion torque. Supination and flexion endurance was 90% of the contralateral arm in 81% (21/26) and 65% (17/26) of subjects, respectively. Ten subjects (39%) achieved 90% strength of the contralateral arm on at least four of five strength tests. Eight of the 26 patients were evaluated pre- and post-surgery. As compared to the contralateral limb, chronic distal biceps rupture was found to have a mean [95%CI] deficit in peak supination torque of 31.0 [21.0, 42.9]% (p=0.002). Mean deficit in peak flexion torque of 34.2 [23.1, 45.4]% (p <0.001). Reconstruction resulted in an increase in peak supination torque of 33.5 [8.7, 58.3]% (p=0.0162), increase in peak flexion torque of 35.0 [6.4, 63.6]% (p=0.023), increase in isometric strength of 57.6 [36.1, 79.1]% (p<0.001), increase in supination endurance of 0.6 [-22.2, 23.4]% (p=0.668), and a decrease in flexion endurance of 4.8 [-23.3, 13.7](p=0.478). Ninety-six percent of the patients (25/26) were satisfied, or very satisfied with the overall outcome of the surgery, while median Mayo score post-reconstruction was 100 (range: 55–100). Chronic distal biceps tendon rupture results in less supination loss and greater flexion loss than previously reported. Reconstruction with tendon graft results in a significant, but incomplete recovery of peak supination and flexion torque, but no significant change in endurance. Clinical patient satisfaction with surgical outcomes is high

Introduction: Neglected Achilles tendon ruptures are a management challenge. Several surgical techniques have been described. A two centre, two surgeon, two year longitudinal study was undertaken to report the results of reconstruction of neglected Achilles tendon rupture using a free autologous gracilis tendon graft. Methods: Fourteen patients underwent surgery for a neglected rupture of the Achilles tendon occurring between 65 days and nine months before the operation. All were prospectively followed up for two years. Results: No patients experienced any problems in the wound used to harvest the tendon of gracilis. Four patients were managed conservatively following a superficial infection of the achilles tendon surgical wound. No patients developed a deep vein thrombosis or sustained a re-rupture. All patients were able to walk on tiptoes, and no patient used a heel raise or walked with a visible limp. The maximum calf circumference remained significantly decreased in the operated leg at latest follow up. The operated limb was significantly less strong than the non-operated one. Conclusions: The management of neglected subcutaneous tears of the Achilles tendon by free gracilis tendon grafting is safe but technically demanding. It affords good recovery, even in patients with a neglected rupture of nine months’ duration. These patients should be warned that they are at risk of post-operative complications, and that their ankle plantar flexion strength can remain reduced

Problem: Surgical technique and short term results of ligament reconstruction with trizeps tendon graft in posterolateral rotational instability of the elbow. Methods: From 2003 to 2006 posterolateral ligament reconstruction with a single strand trizeps tendon graft was performed in 38 patients with posterolateral instability of the elbow, mainly associated with refractory lateral epicondylitis. The reconstructions were performed with the original O Driscoll technique (6), interference screw fixation (30) and transfixation screw (2). There were no neurological complications, one superficial wound infection resolved by revision and 3 arthroscopic revisions for intraarticular scaring. The first 21 operated patients with a minimum follow up of twelve months were reviewed with a subjective 100 point rating score. Results: From 21 patients 4 could not be reached by letter or telephone, 2 patients were excluded for pre-operative stiffness and previous operations other than extensor release. 15 patients could be evaluated. Average follow up was 15,1, min 12, max 24 months. Patients satisfaction with the operation was rated very good by 6 patients (40%), good by 5 (33,3%) unchanged by 4 (26,7 %), none worsened. Mean postoperative score was 83/100 points. Mean score for pain was 22,2/30, for ADL 7,3/8, sleep 1,9/2, range of arm motion 9,2/10, extension 9,2/10, flexion 4,6/5, supination 4,7/5, pronation 4,2/5 and strength 20,1/25 points. Conclusion: Single strand posterolateral ligament reconstruction with a trizeps tendon graft in posterolateral instability of the elbow shows reliable short term results. More secure fixation is achieved with bone tunnel fixation and tenodesis or transfixation

We investigated whether strontium-enriched calcium phosphate cement (Sr-CPC)-treated soft-tissue tendon graft results in accelerated healing within the bone tunnel in reconstruction of the anterior cruciate ligament (ACL). A total of 30 single-bundle ACL reconstructions using tendo Achillis allograft were performed in 15 rabbits. The graft on the tested limb was treated with Sr-CPC, whereas that on the contralateral limb was untreated and served as a control. At timepoints three, six, nine, 12 and 24 weeks after surgery, three animals were killed for histological examination. At six weeks, the graft–bone interface in the control group was filled in with fibrovascular tissue. However, the gap in the Sr-CPC group had already been completely filled in with new bone, and there was evidence of the early formation of Sharpey fibres. At 24 weeks, remodelling into a normal ACL–bone-like insertion was found in the Sr-CPC group. Coating of Sr-CPC on soft tissue tendon allograft leads to accelerated graft healing within the bone tunnel in a rabbit model of ACL reconstruction using Achilles tendon allograft. Cite this article: Bone Joint J 2013;95-B:923–8

We report the use of a free tendon graft in 70 patients to repair lesions of the capsuloligamentous complex of the metacarpophalangeal joint of the thumb. Of these 37 had a lesion of the ulnar collateral ligament, 18 of the radial collateral and 11 of the volar plate. Four patients had combined lesions. We outline our techniques and review 51 of the patients. Of those 47 (92%) were satisfied, and all but one had regained full stability. Pinch grip strength was normal in 48. About one-third of the patients had some loss of flexion/extension; this was seldom noticed by the patients and caused no significant disability. Free tendon graft reconstruction is indicated for severe fresh lesions, for old lesions with chronic disability and for lesions which have not responded to conservative management

Purpose. To evaluate the results of quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with four fold Hamstring Tendon Graft using Transfix and Bioabsorbable Interference Screw Fixation. Study Design. Retrospective review. Methods. Sixty-five patients (66 knees) were retrospectively identified by chart review as having undergone quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction, with four fold Hamstring Tendon Graft, using Transfix and Bioabsorbable Interference Screw Fixation. All patients underwent a minimum two-year follow-up. Results. Data were collected on 48 knees in 47 patients (73%) at an average 30.2 months (range 24 to 43) after surgery. Thirty-six patients (37 knees) returned for clinical evaluation (56% return) and subjective follow-up only was obtained in 11 patients (17%). The mean Lysolm knee score was 91 (range, 45 to 98), with a mean of 97 for the uninvolved knee. The mean Tegner activity score was 5.7 (range 3 to 7). The KT-1000 arthrometer mean side-to-side difference for manual maximum displacement was 2.03 mm (range -1 to 8). The mean International Knee Documentation Committee knee score was 83 (range 47 to 100). Patients who underwent associated partial meniscectomy or meniscal repair had significantly lower International Knee Documentation Committee scores than patients without associated procedures (P < 0.01). Conclusions. Quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation is comparable with other methods of anterior cruciate ligament reconstruction in terms of patient satisfaction, knee stability, and function

INTRODUCTION: The process of ligamentization includes the histological and structural remodelling of the tendons graft to ligamentous tissue. There is little information documenting the mechanism of ligamentization process in molecular level. A number of essential genes are involved in this process and their expression can be regulated through complex biochemical pathways. Animal studies have shown that transcutaneous application of low intensity pulsed ultrasound (LiUS) accelerate the tendon and ligament healing process and recent reports have proven the efficacy of the transosseous application of LiUS for both enhancement and monitoring of the bone healing. The purpose of this study is to investigate the effect of transosseous low-intensity pulsed ultrasound (LiUS) during lingamentization process on the healing at tendon graft-bone interface in rabbits, by examining the expression levels of TGF-β1, biglycan and collagen I using semi-quantitive RT-PCR. MATERIALS AND METHODS: Twenty-eight New Zealand rabbits were used in this study. The anterior cruciate ligament was excised and replaced with the long digital extensor. Custom-made ultrasound transducers were implanted onto the bone fragment and along the surface of the bone tunnel at the right knees of the rabbits (study group). The LiUS-treated animals received 200-μsec bursts of 1 MHz sine waves with pulse repetition rates of 1 KHz and average intensity of 30 mW/cm2, for 20 minutes daily, while the left knee received no LiUS (control group). Semi-quantitative RT-PCR was performed from RNA samples representing both study and control groups at 1, 2, 3, 5, 7, 8, 9, 12, 14 and 21 days, using specific primers. RESULTS: Analysis of the RT-PCR products showed that there is significant up-regulation of biglycan and collagen-encoding genes in the study group compared to the control group. In addition, TGFb1-encoding gene exhibits a bimodal profile. In the study group, it represses its mRNA levels from day 1 until day 9 and then the initial expression levels are restored. The control group showed no essential alteration of expression levels for TGFb1. DISCUSSION: Transosseous LiUS treatment affects the expression levels of significant genes like TGF-β1, big-lycan and collagen type I. All the above studied genes mediate important biochemical pathways in lingamentization process and possibly enhance the healing rate of the tendon graft-bone interface in a bone tunnel in rabbits. The present report is supportive of the hypothesis that transosseous application of LiUS enhances tendon graft healing to bone through effects on molecular level. These present findings suggest that indeed ultrasound treatment after joint ligament reconstruction may facilitate earlier rehabilitation

Objectives: The replacement tissue used for anterior cruciate ligament reconstruction undergoes extensive biologic remodelling and incorporation after implantation. These changes, in which the tendon loses some of its characteristic features and adopts those typically associated with ligaments, has been referred to as ligamentization. The purpose of this study was to identify the proinflammatory response in the healing graft in the early phase. Methodes: Twenty New Zealand White Rabbits underwent ACL reconstruction with a semitendinosus tendon. Animals were sacrificed at 3 and 6 weeks. The harvested tissue including parts of remaining grafted tendon and genuine anterior cruciate ligament at time of the surgery as well as the tendon graft withdrawn at sacrification were prepared for immunohistochemical, histomorphometry and electromicroscopical analysis; synovia samples were taken at the sacrification as well. The tissues were immunostained for IL-1beta, TGF-beta, TNF-alpha (induction of inflammatory cascade), COX-2 (mediator of inflammatory response), Matrix Metalloproteinases (MMP-1, MMP-3, MMP-13, matrix destructive enzymes), TIMP-2 (Tissue Inhibitor of MMPs); the PGE2 (mediator of inflammatory response) content in the synovia was quantified by ELISA. Results: At 3 weeks after surgery the COX-2+ cells accounted for 70% of all cells present in the graft tissue, and decreased to 28% at 6 weeks. Similar, IL-1beta+ cells within the tendon decreased from week 3 to week 6. Controversly, there was an increase of COX-2, IL-1beta and MMP-1 in the intercellular tissue. The numbers of COX-2+ cells and IL-1beta+ cells at 3 weeks as well as the intercellular area stained positiv for COX-2, IL-1beta and MMP-1 at 6 weeks were significantly larger compared to the genuine ACL (p =< 0.05). At 3 weeks some cells stained positiv for MMP-3 and MMP-13, but not at 6 weeks. There was a slight pericellular staining for TIMP-2 at 3 weeks. TGF-beta+ cells and TNF-alpha+ cells were almost not detectable at every time point. Thus, proinflammatory cytokines and MMPs were synthesized in the early phase after ACL reconstruction by the tendon cells and accumulated at 6 weeks in the intercellular tissue. Conclusions: In the early phase of the graft healing after ACL reconstruction, there was a signifikant increase in proinflammatory cytokines and matrix destructive enzymes in the tendon graft. With the capability of synthesizing cytokines, tendon cells may play a critical role in tendon healing at early time points. Facing the widespread use the bias of cox-2 inhibitors on these immunologic processes has to be checked. Activating matrix destructive enzymes, cytokines appear to be crucial for connective tissue remodelling and graft stability after ACL reconstruction

Aims

Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function.

Graft choices for revision anterior cruciate ligament (ACL) reconstruction and complex ligament reconstructions of the knee are controversial. The aim of our study was to analyze the biomechanical effect of harvesting bone plugs from both the distal and proximal poles of the patella, to simulate a simultaneous harvesting of a Bone – Patellar Tendon – Bone and Quadriceps Tendon – Bone grafts, in a transverse stress environment. Sixty Bovine Patellae were analysed. They were divided into 4 groups – based on the residual bone bridge (percentage of total length of patella) remaining after bone plug resection. 0 – 10%, 11 – 20%, 21 – 30% and > 30%. All patellae were tested in a modified 4 – point bending environment, to a maximum load of 10,000N, in a customized designed jig. This method simulates the axial bending stress on the patella during knee flexion. All dimensions of the patellae were recorded including Depth of patella at bone resection and wall thickness adjacent to plug resection site. All patellae with a 0% bone bridge fractured (Ultimate Tensile Strength/UTS) at a mean Tensile Force of 5863N (Range 3140 – 8730N). There was a subgroup of incomplete fractures – extra-articular fractures – which fractured at 6542N (Range 5085 – 9180N). The remaining specimens failed to fracture. Comparing the UTS and the patellar dimensions, using Weibull’s Statistical Analysis we demonstrated that less than 60% bone plug resection carried a very low probability of fracture. This study demonstrates the safe criteria for bone – tendon graft harvesting from both the proximal and distal poles of the patella. With regards to a normal human patella, a 40% bone – bridge is approximately a 20mm bone – bridge. We conclude that the simultaneous harvesting of Bone – Patellar Tendon – Bone and Quadriceps Tendon – bone grafts from a patella has no significant increase in the fracture risk of the patella

Objectives

This study investigated the biomechanical performance of decellularized porcine superflexor tendon (pSFT) grafts of varying diameters when utilized in conjunction with contemporary ACL graft fixation systems. This aimed to produce a range of ‘off-the-shelf’ products with predictable mechanical performance, depending on the individual requirements of the patient.

The purpose of our study was to determine the effect of 4 weeks and 12 weeks of implantation on the strength of a tendon graft in a bone tunnel using a low-profile fixation device, Evolgate, in an extra-articular ovine model. Moreover, we evaluated the histological changes. The common digital extensor tendon was detached from the lateral femoral condyle and fixed with the Evolgate device in a 30-mm-long tunnel placed obliquely across the dense metaphyseal bone of the proximal tibia. We performed either biomechanical or histological study. Three sheep were sacrified at time 0 and their posterior limbs were used for biomechanical tests. Six sheep were used for biomechanical tests at time 1 (4 weeks) and at time 2 (12 weeks). The other three sheep were used for histological evaluation after 4 and 12 weeks of implantation. The biomechanical tests included a 50 N preload applied for 10 s and a cyclic load test in 50-N increments until failure to evaluate the ultimate failure load. We used a paired t-test to evaluate the difference between group at T1 and group at T2 with the control group at time 0, respectively. Tests were performed using an electromechanic machine (Zwick-Roell Z010, Zwick-Roell, Ulm, Germany). Data were recorded with dedicated software (Textexpert 8.1, Zwick-Roell). The biomechanical results show an improvement of about 50% in strength after 4 and 12 weeks post-implantation, respectively. The histological evaluation shows a layer of cellular, fibrous tissue between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganised during the healing process. The collagen fibres that attached the tendon to the bone resembled Sharpey fibres. The strength of the interface was noted to have significantly and progressively increased between the second and the 12th week after the transplantation. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralisation, and maturation of the healing tissue, noted histologically

Abstract

Aims

To evaluate the donor site morbidity and tendon morphology after harvesting whole length, full-thickness peroneus longus tendon (PLT) proximal to the lateral malleolus for ligament reconstructions or tendon transfer.