Aims. Avulsion of the proximal hamstring tendon origin can result in significant functional impairment, with surgical re-attachment of the tendons becoming an increasingly recognized treatment. The aim of this study was to assess the outcomes of surgical management of proximal hamstring tendon avulsions, and to compare the results between acute and chronic repairs, as well as between partial and complete injuries. Methods. PubMed, CINAHL, SPORTdiscuss, Cochrane Library, EMBASE, and Web of Science were searched. Studies were screened and quality assessed. Results. In all, 35 studies (1,530 surgically-repaired hamstrings) were included. Mean age at time of repair was 44.7 years (12 to 78). A total of 846 tears were acute, and 684 were chronic, with 520 tears being defined as partial, and 916 as complete. Overall, 92.6% of patients were satisfied with the outcome of their surgery. Mean Lower Extremity Functional Score was 74.7, and was significantly higher in the partial injury group. Mean postoperative hamstring strength was 87.0% of the uninjured limb, and was higher in the partial group. The return to sport (RTS) rate was 84.5%, averaging at a return of 6.5 months. RTS was quicker in the acute group. Re-rupture rate was 1.2% overall, and was lower in the acute group. Sciatic nerve dysfunction rate was 3.5% overall, and lower in the acute group (p < 0.05 in all cases). Conclusion. Surgical treatment results in high satisfaction rates, with good functional outcomes, restoration of muscle strength, and RTS. Partial injuries could expect a higher functional outcome and muscle strength return. Acute repairs result in a quicker RTS with a reduced rate of re-rupture and sciatic nerve dysfunction. Cite this article: Bone Jt Open 2022;3(5):415–422

Avulsion of the proximal hamstring tendon from the ischial tuberosity is an uncommon but significant injury. Recent literature has highlighted that functional results are superior with surgical repair over non-surgical treatment. Limited data exists regarding the optimal rehabilitation regime in post-operative patients. The aim of this study was to investigate the early interim patient outcomes following repair of proximal hamstring tendon avulsions between a traditionally conservative versus an accelerated rehabilitation regimen. In this prospective randomised controlled trial (RCT) 50 patients underwent proximal hamstring tendon avulsion repair, and were randomised to either a braced, partial weight-bearing (PWB) rehabilitation regime (CR = 25) or an accelerated, unbraced, immediate full weight-bearing (FWB) regime (AR group; n = 25). Patients were evaluated preoperatively and at 3 months after surgery, using the Lower Extremity Functional Scale (LEFS), Perth Hamstring Assessment Tool (PHAT), visual analog pain scale (VASP), Tegner score, and 12-item Short Survey Form (SF-12). Patients also filled in a diary questioning postoperative pain at rest from Day 2, until week 6 after surgery. Primary analysis was by per protocol and based on linear mixed models. Both groups, with respect to patient and characteristics were matched at baseline. Over three months, five complications were reported (AR = 3, CR = 2). At 3 months post-surgery, significant improvements (p<0.001) were observed in both groups for all outcomes except the SF-12 MCS (P = 0.623) and the Tegner (P = 0.119). There were no significant between-group differences from baseline to 3 months for any outcomes, except for the SF-12 PCS, which showed significant effects favouring the AR regime (effect size [ES], 0.76; 95% CI, 1.2-13.2; P = .02). Early outcomes in an accelerated rehabilitation regimen following surgical repair of proximal hamstring tendon avulsions, was comparable to a traditionally conservative rehabilitation pathway, and resulted in better physical health-related quality of life scores at 3 months post-surgery. Further long term follow up and functional assessment planned as part of this study

Proximal hamstring tendon avulsion from the ischial tuberosity is a significant injury, with surgical repair shown to have superior functional outcomes compared to non-surgical treatment. However, limited data exists regarding the optimal rehabilitation regime following surgical repair. The aim of this study was to investigate patient outcomes following repair of proximal hamstring tendon avulsions between a conservative (CR) versus an accelerated rehabilitation (AR) regimen. This prospective randomized controlled trial (RCT) randomised 50 patients undergoing proximal hamstring tendon repair to either a braced, partial weight-bearing rehabilitation regime (CR=25) or an accelerated, unbraced regime, that permitted full weight-bearing as tolerated (AR=25). Patients were evaluated pre-operatively and at 3 and 6 months post-surgery, via patient-reported outcome measures (PROMs) including the Lower Extremity Functional Scale (LEFS), Perth Hamstring Assessment Tool (PHAT) and 12-item Short Form Health Survey (SF-12). Primary analysis was per protocol and based on linear mixed models. Both groups were matched at baseline with respect to patient characteristics. All PROMs improved (p>0.05) and, while the AR group reported a significantly better Physical Component Score for the SF-12 at 3 months (p=0.022), there were no other group differences. Peak isometric hamstrings strength and peak isokinetic quadriceps and hamstrings torque symmetry were all comparable between groups (p>0.05). Three re-injuries have been observed (CR=2, AR=1). After proximal hamstring repair surgery, post-operative outcomes following an accelerated rehabilitation regimen demonstrate comparable outcomes to a traditionally conservative rehabilitation pathway, albeit demonstrating better early physical health-related quality of life scores, without an increased incidence of early re-injury

Objectives. The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle. Materials and Methods. Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle. Results. At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle. Conclusions. Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle. Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247–252. DOI: 10.1302/2046-3758.56.2000585

Abstract. Purpose. Since arthroscopic reconstruction of the anterior cruciate ligament (ACL) started, the use of peroneus longus grafts for primary ACL reconstruction (ACLR) was never thought of as there is very scant literature on it. So, our study aims to compare the functional outcome and complications in patients with ACL injury managed by ACLR with peroneus longus tendon (PLT) and hamstring tendons (HT) respectively. Materials and Methods. Patients with 16–50 years of either gender presenting with symptomatic ACL deficiency were admitted for arthroscopic single bundle ACLR and allocated into two groups (PLT and HT) operated and observed. Functional scores (IKDC and Lysholm score), clinical knee evaluation, donor site morbidity (AOFAS score) and thigh circumference were recorded preoperatively and at six months, one year post-operatively. The same post-op rehabilitation protocol was followed in both groups. Results. 194 patients (hamstring n=96, peroneus n=98) met the inclusion criteria. There were no significant differences between the pre-op, six months post-op and one-year postoperative score between the hamstring and peroneus longus groups in the IKDC (p=0.356) and Lysholm knee score (p=0.289). The mean for the AOFAS was 99.05±3.56 and 99.80±0.70 in the PLT and HT group respectively showing no statistical difference, with a significant improvement in thigh muscle wasting among the PLT group at final follow-up (p<0.001). Conclusion. We observed similar knee stability, functional outcome and no obvious donor site morbidity among both groups and recommend that a PL graft may be a safe, effective, and viable option for arthroscopic single bundle ACL reconstruction

Aims: Patellar instability and painful patellar mal-tracking are common challenging conditions faced by a knee surgeon. Our purpose was to describe an arthroscopy assisted method of medial patellofemoral ligament reconstruction to address these conditions present our results using this modified technique. Materials & Method: Between April 2001 and December 2003, 22 knees in 20 consecutive patients underwent arthroscopically assisted MPFL reconstruction using an autologous hamstring tendon. There were 12 female and 8 male patients passed with a mean age of 29.9 years. The knees were assessed using Fulkerson’s and Kujala’s scoring systems and the mean follow-up period was 20.8 months (range 12–35). The technique uses a single hamstring tendon with undisturbed biological distal attachment, where the free end is routed through a longitudinal tunnel in the dorso-medial aspect of the patella and fixed to an isometric point near the medial femoral epicondyle using an interference screw. The position of femoral attachment is the most important factor in achieving an isometric graft. Results: There was a significant increase (p=< 0.0001) in mean Fulkerson score of 35.4 from a pre-operative value of 47.4 to a post-operative value of 82.9. Sixteen patients rated their knees as good or excellent and there was only one complication of complex regional pain syndrome. 11 of 13 patients who were keen on sports returned to their sports at a mean of 3.9 months (range 1–10). Conclusion: We report good results with this technique of medial patello femoral ligament reconstruction and would advocate it as an effective surgical option for patients with recurrent lateral instability as well as those with painful lateral mal-tracking

Hamstring tendons are commonly used for Anterior Cruciate Ligament (ACL) reconstruction. In our series of 100 consecutive Hamstring ACL reconstructions, a four-strand graft was less than 7.0 mm in 5 patients. The aim of this study was to develop a screening test to assess the size of the hamstring tendon and so aid in the pre operative planning and patient counselling especially if hamstring size was deemed to be inadequate. A retrospective study of 100 consecutive hamstring ACL reconstructions analysed the correlation of the tendon size to height, weight and body mass index. A prospective double blind study was also set up involving independent observations by a musculoskeletal radiologist and the lead Orthopaedic surgeon. Result. There was no correlation between the anthropometric measures and hamstring size in the retrospective study. A total of 27 limbs were assessed sonographically, in 26 patients. Spearman's rank correlation coefficient was found to Pearson's r = 0.0786; p = 0.715. Conclusion. Pre-operative anthropometric measures and Ultrasound could not be used as a screening test to detect inadequate hamstrings in the clinical setting

The purpose of this study was to report the outcome of ‘isolated’ anterior cruciate ligament (ACL) ruptures treated with anatomical endoscopic reconstruction using hamstring tendon autograft at a mean of 15 years (14.25 to 16.9). A total of 100 consecutive men and 100 consecutive women with ‘isolated’ ACL rupture underwent four-strand hamstring tendon reconstruction with anteromedial portal femoral tunnel drilling and interference screw fixation by a single surgeon. Details were recorded pre-operatively and at one, two, seven and 15 years post-operatively. Outcomes included clinical examination, subjective and objective scoring systems, and radiological assessment. At 15 years only eight of 118 patients (7%) had moderate or severe osteo-arthritic changes (International Knee Documentation Committee Grades C and D), and 79 of 152 patients (52%) still performed very strenuous activities. Overall graft survival at 15 years was 83% (1.1% failure per year). Patients aged < 18 years at the time of surgery and patients with > 2 mm of laxity at one year had a threefold increase in the risk of suffering a rupture of the graft (p = 0.002 and p = 0.001, respectively). There was no increase in laxity of the graft over time. ACL reconstructive surgery in patients with an ‘isolated’ rupture using this technique shows good results 15 years post-operatively with respect to ligamentous stability, objective and subjective outcomes, and does not appear to cause osteoarthritis

Introduction and Aims: To describe the arthroscopically assisted technique of medial patello-femoral ligament reconstruction using a hamstring tendon and evaluate the results of the procedure. Since April 2001 the senior author has performed 20 cases. One was bilateral. Average age was 30 years (range 17–52). Method: The study group comprised nine males and 11 females. The indication for surgery was recurrent lateral dislocation in 13 and lateral mal-alignment in the remaining seven. Thirteen of the 20 had undergone prior surgery, eight an isolated lateral release and five a lateral release combined with open extra-synovial medial retinacular plication. Key features of this technique are use of the 70-degree arthroscope in the supero-lateral portal, endoscopic lateral release and use of semitendinosis or gracilis tendon attached distally. The tendon is passed through drill holes in the medial aspect of the patella and attached to a clinically isometric point near the medial femoral condyle. The tension is assessed arthroscopically and clinically before attachment. The semitendinosis tendon was used in 11 cases and gracilis in 10. Results: All had subjective improvement with regard to patellar instability, activity level and relief of pain. There were no recurrent dislocations. The only patient in whom the tendon was attached to the distal adductor magnus required revision surgery with improvement after attachment of another tendon to bone at the isometric point. Mean follow-up was 17 months (range 4–33 months). The mean time to return to work was five weeks (range five days–12 weeks) and return to sport 10 weeks (range 3–16 weeks). The Fulkerson patello-femoral joint evaluation score improved from 46/100 pre-operatively to 74/100. Only four described the state of the knee subjectively as fair and the rest good or excellent. All patients regained full range of motion. Conclusion: This arthroscopically assisted technique of medial patello-femoral ligament reconstruction using a hamstring tendon allows the patella to be seen and felt to articulate in the trochlea groove. It allows early rehabilitation, minimal post-operative pain, provides patella stability and significant functional improvement with rapid recovery and a low incidence of skin numbness

Recurrent patellar instability and anterior knee pain is a common problem after patellar dislocation. The medial patellofemoral ligament (MPFL) which contributes 40–80% of the total restraining forces is either attenuated or ruptured in these patients. Various techniques have been described in reconstructing this MPFL using hamstrings tendons. We wish to share our experience in treating these patients using ipsilateral semitendinosus tendon anchored to the medial femoral condyle and medial side of the patella using biotenodesis screws. Study design and methods: 15 patients were assessed with a mean follow up of 12 months. All patients had pre-operative true lateral knee x-ray, MRI or CT scan to look at trochlear dysplasia and the sulcus tuberosity distance. They all under went MPFL reconstruction using ipsilateral semitendinosus tendon. Two patients had sulcus tuberosity distance greater than 20 mm and they under went a tibial tubercle transfer in addition. Two patients had trochlear dysplasia and hence a trochleaplasty was also done. In skeletally mature patients the hamstrings tendon was anchored to the medial side of the patella in a 5x15mm blind tunnel using biotenodesis screw. This significantly reduces the risk of having patella fracture. In. children the graft was sutures to the soft tissues along the medial side of the patella and the medial femoral condyle. All patients were treated by the same surgeon and assessments were performed by a different surgeon based . on Kujala scores and Tegner scores. Results: Symptom relief was noted in all patients with in 3 months. No patient had patella dislocation or fracture after this procedure. They all had full range of movements and their Kujala scores and Tegner scores were good to excellent. Conclusion: MPFL reconstruction using hamstrings tendon anchored to the medial side of the patella and femur using biotenodesis screw gave a good result clinically and is associated with fewer complications including patellar fractures

A total of 30 patients who underwent endoscopic reconstruction of the anterior cruciate ligament using quadrupled hamstring tendons, through a single drill hole in the femur, had MRI 24 to 28 months after operation. In 18 patients the scans revealed that both the anterior and posterior portions of the graft ran in parallel from the inside of the femoral to the tibial tunnel. In 12, the posterior bundle had moved anteriorly and the anterior bundle could not be identified at the anterodistal border of the femoral tunnel. The mean difference in the anterior laxity, when compared with the contralateral knee, was 2.0 ± 1.7 mm and 4.3 ± 2.8 mm for the two types, respectively. Damage to the anterior bundle may occur when using the endoscopic technique because of biomechanical disadvantages, including concentration of loading and repetitive bending stress in the anterior bundle at the opening of the femoral tunnel

To share our results following Medial Patellofemoral ligament (MPFL) reconstruction for patellar instability problems using ipsilateral semitendinosus graft anchored to the patella and the medial femoral condyle using biotenodesis screws. Study design and methods: 35 patients were assessed with a mean follow up of 18 months. All patients had preoperative true lateral knee x-ray, MRI or CT scan to look at trochlear dysplasia and the sulcus tuberosity distance. They all under went MPFL reconstruction using ipsilateral semitendinosus tendon. Two patients had sulcus tuberosity distance greater than 20 mm and they under went a tibial tubercle transfer in addition. Two patients had trochlear dysplasia and hence a trochlearplasty was also done. In skeletally mature patients the hamstrings tendon were anchored to the medial side of the patella in a 5×15mm blind tunnel using biotenodesis screw. This significantly reduces the risk of having patella fracture. All patients were treated by the same surgeon and assessments were performed by a different surgeon based on kujala scores and tegner scores. Results: Symptom relief was noted in all patients with in 3 months. No patient had patella dislocation or fracture after this procedure. They all had full range of movements and their kujala scores and tegner scores were good to excellent. Conclusion: MPFL reconstruction using hamstrings tendon anchored to the medial side of the patella and femur using biotenodesis screw gave a good result clinically and is associated with fewer complications including patellar fractures

This prospective longitudinal study compared the results of isolated endoscopic ACL reconstruction utilising 4-strand hamstring tendon (HT) or patellar tendon (PT) autograft over 15-years with respect to reinjury, clinical outcomes and osteoarthritis. Ninty consecutive patients with isolated ACL rupture were reconstructed with a PT autograft and 90 patients received HT autograft, with an identical surgical technique. Patients were assessed at 2, 5, 7, 10 and 15 years. Assessment included the IKDC Knee Ligament Evaluation, radiographic evaluation, KT1000, Lysholm Knee Score, kneeling pain, and clinical outcomes. Subjects who received the PT graft had significantly worse outcomes compared to those who received the HT graft at 15 years for the variables of radiologically detectable osteoarthritis (p=0.03), motion loss (p=0.01), single leg hop test (p=0.002), participation in strenuous activity (p=0.05), and kneeling pain (p=0.04). There was no significant difference between the HT and PT groups in overall IKDC grade (p=0.31). ACL graft rupture occurred in 16% of HT group and 8% of the PT group (p=0.07). ACL graft rupture was associated with non-ideal tunnel position (odds ratio 5.0) and males (odds ratio 3.2). Contralateral ACL rupture occurred in significantly more PT patients (24%) than HT patients (12%) (p=0.03), and was associated with age < 18 years (odds ratio 4.1) and the patellar tendon graft (odds ratio 2.6). Radiologically detectable osteoarthritis at 15 years was associated with the PT graft (odds ratio 2.3). Significant differences have developed in the groups at 15 years after surgery which were not seen at earlier reviews. Compared to the HT Group, the PT group had significantly worse outcomes with respect to radiological osteoarthritis, extension loss and functional tests but no significant difference in laxity was identified. There was a high incidence of ACL injury after reconstruction, to both the reconstructed and the contralateral knee

Purpose: To determine whether the tendon harvester can influence harvested tendon characteristics and soft tissue disruption. Summary: We compared two harvesters with regards to the length of tendon obtained and soft tissue disruption during hamstring tendon harvesting. Thirty six semitendinosus and gracilis tendons were harvested using either a closed stripper or a blade harvester in 18 paired knees from 9 human fresh cadavers. Use of the blade harvester gave longer lengths of usable tendon (p=0.002), whilst minimising the stripping of muscle (p=0.013). Conclusion: Our results suggest that the type of harvester per se can influence the length of tendon harvested as well as soft tissue disruption. Requesting such data from the industry prior to deciding which harvester to use seems desirable

Purpose of the study: The issue of which graft to choose for anterior cruciate ligament (ACL) reconstruction is still a matter of debate. An analysis of the literature reveals the difficulty encountered when performing comparative trials. It is also difficult to demonstrate significant differences with results obtained with an insufficient number of patients. We propose here a meta-analysis in order to combine the results obtained with different comparative studies. Material and methods: The literature search (Medline 1990–2005) was based on the following selection criteria: ACL reconstruction, patellar tendon (PT), gracilis and semitendinous (four-strand hamstring) reconstruction and comparative prospective study. Studies were retained with: > 30 patients per group, minimum follow-up 24 months, IKDC score. Evaluation criteria retained were: anterior pain, resumed activity, IKDC score, differential laxity. The relative risk (RR) statistical method with 95% confidence interval (CI) was applied. Means were calculated and the chi-square and z-tests were applied. Results: Thirteen studies satisfied our inclusion criteria. These studies had included more than 1300 transplants. Mean rate of anterior pain was 23.2% with PR and 17.3% with hamstring reconstructions. The RR was 0.73 with a CI different from 1. The difference was significant. Resumption of sports activities at the same level, subjective assessment, number of failures, and overall IKDC score were not statistically different between the two types of transplants. The IKDC laxity score was not different but the residual maximal manual differential laxity was greater in the hamstring patients than in the patellar patients in 80% of the cases. Conclusion: At the observed follow-up, free grafting with a four-strand hamstring tendon or a patellar tendon is an effective method for reconstruction of the ACL. Anterior pain is more frequent with the patellar tendon method and residual laxity is greater with the hamstring method. The long-term outcome will determine whether the residual laxity observed with the hamstring graft has a deleterious effect on the meniscocartilaginous structures. This criteria would minimize the advantage of this technique over the patellar tendon technique concerning the initial anterior pain

Aim: To compare, in a longitudinal study, the clinical outcomes of endoscopic anterior cruciate ligament (ACL) reconstruction with either a four-strand hamstring tendon (HT) or a patellar tendon (PT) autograft over a five-year period, when a similar operative procedure is followed for both groups. Method: Ninety patients with isolated ACL ruptures who had received PT autografts and another 90 who had received HT autografts were studied annually for five years. Fifty patients were randomised as a subgroup. The assessments included the IKDC Knee Ligament Evaluation, KT1000, Lysholm Knee Score, thigh atrophy, kneeling pain, hamstring pain and radiographs. Results: The median Lysholm Knee Score was 96 for the PT group and 95 for the HT group. No significant difference was found for subjective knee function, overall IKDC assessment, X-ray findings, manual ligament KT1000 instrumented testing, graft rupture or contra-lateral ACL rupture. There was an increasing incidence of fixed flexion deformity seen in the PT group. There was no difference in the requirement for subsequent surgery. The incidence of kneeling pain at five years was significantly higher in the PT group. The results of the randomised patients were identical to the sequential patients. Conclusions: Endoscopic reconstruction of the ACL utilizing either type of autograft restored knee stability and was protective of the meniscus despite a high level of sporting activity. We found a worrying trend towards an increasing incidence of fixed flexion deformity with time in the PT group. Pain when kneeling also remained a persistent problem in this subgroup. PT grafts appeared tighter clinically and, with the KT 1000, when assessed up to three years post operatively, compared with HT grafts. Thereafter the results were similar

Hamstring grafts have been associated with reduced strength, donor site pain and muscle strains following Anterior Cruciate Ligament Reconstruction (ACLR). Traditional graft fixation methods required both semitendinosus and gracilis tendons to achieve a graft of sufficient length and diameter, but newer techniques allow for shorter, broad single tendon grafts.

This study seeks to compare the outcomes between Single Tendon (ST) and Dual Tendon (DT) ACLR, given there is no prospective randomised controlled trial (RCT) in the literature comparing outcomes between these options.

In this ongoing RCT: (ANZ Clinical Trials Registry ACTRN126200000927921) patients were recruited and randomised into either ST or DT groups. All anaesthetic and surgical techniques were uniform aside from graft technique and tibial fixation. 13 patients were excluded at surgery as their ST graft did not achieve a minimum 8mm diameter. 70 patients (34 ST, 36DT) have been assessed at 6 months, using PROMS including IKDC2000, Lysholm and Modified Cincinnati Knee, visual analog scale for pain frequency (VAS-F) and severity (VAS-S), dedicated donor site morbidity score, KT-1000 assessment, and isokinetic strength.

Graft diameters were significantly lesser in the ST group compared to the DT group (8.44mm/9.11mm mean difference [MD],-0.67mm; P<0.001). There was a significant and moderate effect in lower donor site morbidity in the ST group compared to the DT group (effect size [ES], 0.649; P = .01). No differences between groups were observed for knee laxity in the ACLR limb (P=0.362) or any of the patient-reported outcome measures (P>0.05). Between-group differences were observed for hamstrings strength LSI favouring the ST group, though these were small-to-moderate and non-significant (ES, 0.351; P = .147).

ST (versus DT) harvest results in significantly less donor site morbidity and this is the first prospective RCT to determine this. There were no differences between ST and DT hamstring ACLR were observed in PROMs, knee laxity and hamstring strength. Younger female patients tend to have inadequate single tendon size to produce a graft of sufficient diameter, and alternative techniques should be considered. Further endpoints include radiological analysis, longer term donor site morbidity, revision rates and return to sport and will continue to be presented in the future.

The optimal method of tibial fixation when using a hamstring tendon autograft in anterior cruciate ligament (ACL) reconstruction is unclear. This study aimed to compare the risk of revision ACL reconstruction between suspensory and interference devices on the tibial side.

Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. Only patients with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. The rate of revision ACL reconstruction was compared between suspensory and interference devices on the tibial side. Univariate Chi-Square test and multivariate Cox regression was performed to compute hazard ratios (HR) and 95% confidence intervals (CI) with adjustment for age, gender, time-to-surgery, activity at the time of injury, number of graft strands and graft diameter.

6145 cases were analyzed, of which 59.6% were fixed with a suspensory device on the tibial side (n = 3662), 17.6% fixed with an interference screw with a sheath (n = 1079) and 22.8% fixed with an interference screw without a sheath (n = 1404). When compared to suspensory devices (revision rate = 3.4%), a higher risk of revision was observed when using an interference screw with a sheath (revision rate = 6.2%, adjusted HR = 2.05, 95% CI 1.20 – 3.52, p = 0.009) and without a sheath (revision rate = 4.6%, adjusted HR = 1.81, 95% CI 1.02 – 3.23, p = 0.044). The number of graft strands and a graft diameter of ≥8 mm did not influence the risk of revision.

When reconstructing the ACL with a hamstring tendon autograft, the use of an interference screw, with or without a sheath, on the tibial side has a higher risk of revision when compared to a suspensory device.

The aim of our study was to examine the outcome of ACL reconstruction by using four strand hamstring tendon autografts.

Material and Methods: the study included 44 patients (29 males,15 females;mean age 26;18–45 years). The diagnosis was based on clinical examination and imaging techniques. The operation was performed arthroscopically 4–62 weeks after the injury. The tendon was fixed in the tibia with an interference screw and in the femur with three different methods cross pin in 16 cases, transfix pin in 11 cases and Endo button in 17 cases.

Results: The mean follow up was 28 months (12–42). The mean Lysholm score was improved from 35–65 (mean 49) preoperativelly to 55–100 postoperativelly (mean 88).

5 patients had laxity > 3mm when compared to the healthy knee by using the KT-1000 arhthrometric testing. 2 of the latter patients complained of a feeling of knee joint instability which occurred due to inaccurate positioning of the femoral tunnel. In 2 cases the transfix pins were displaced and removed on the 4th and 15th post-operative month.

The tunnel expansion was measured by an X-Ray or a CT scan. The tibial tunnel expansion was 0–2.5mm (mean 1.2) or 18% and the femoral tunnel expansion was 0–3 mm (mean 1.4) or 26%. 8 patients reported mild pain which did not restrict their activities. A 5 degree loss of extension was noticed in one patient who continues physiotherapy.

28 of the above patients suffered also from a meniscal injury that was managed arthroscopically.

Conclusion: ACL reconstruction by using four strand hamstring tendon autografts is safe, highly successful with very few complications when proper graft preparation and accurate tunnel placement is achieved.

Aims: The aims of this study were to evaluate the biomechanical properties and mode of failure of four methods of fixation of hamstring anterior cruciate ligament (ACL) grafts. The fixation methods investigated included titanium round headed cannulated interference (RCI) screws, bioabsorbable RCI screws, Endobuttons and Bollard fixation. A 2-strand equine extensor tendon graft model was used because a previous study has shown it to have equivalent biomechanical properties to that of 4-strand human semitendinosus and gracilis tendon grafts.

Method: Thirty-two stifle joints were obtained from skeletally mature pigs, the soft tissues were removed and the ACL and PCL were sacrificed. Tibial tunnel preparation was standardised using the Mayday rhino horn jig to accurately position a guide wire over which an 8mm tunnel was drilled. A 2-strand equine tendon graft was then introduced into the tibial tunnel and secured with either a titanium RCI screw, a bioabsorbable RCI screw, an Endobutton or an expansile Bollard. The proximal part of the graft was attached to the crosshead of a materials testing machine using the Soffix. Five of each method of fixation were tested mechanically to ultimate failure and under cyclical loading.

Results: The mean ultimate tensile loads (UTL) were: titanium RCI screw = 444 N, bioabsorbable RCI screw = 668 N, Endobutton = 999 N and Bollard = 1153 N. The mode of failure for all RCI screws involved progressive tendon slippage past the screw. Under cyclic loading conditions the titanium and bioabsorbable RCI screws rapidly failed after several hundred 5 to 150 N cycles due to tendon damage and slippage. Both the Bollards and Endobuttons survived 1500 cycles at 50–450N, with less tendon slippage.

Conclusion: Titanium and bioabsorbale RCI screws provide poor initial fixation of tendon grafts used for ACL reconstruction and fail rapidly under cyclic loading. Both Bollards and Endobuttons provide sufficiently high UTL’s and survive cyclic loading to allow early postoperative mobilisation and rehabilitation. Caution must be used in the early postoperative period when using interference screws to secure a hamstring tendon graft because early progressive tendon slippage may result in excessive graft elongation and early clinical failure.