INTRODUCTION. In native knees the anterior cruciate ligament (ACL) plays a major role in joint stability and kinematics. Sacrificing the ACL in contemporary total knee arthroplasty (TKA) is known to cause abnormal knee motion, and reduced function. Hence, there is growing interest in the development of ACL retaining TKA implants. Accommodation of ACL insertion around the tibial eminence is a challenge with these designs. Therefore, a reproducible and practical test setup is necessary to characterize the strength of the ACL/bone construct in ACL retaining implants. Seminal work showed importance of loading the ACL along its anatomical orientation. However, prior setups designed for this purpose are complex and difficult to incorporate into a standardized test for wide adoption. The goal of this study was to develop a standardized and anatomically relevant test setup for repeatable strength assessment of ACL construct using basic force-displacement testing equipment. METHODS. Cadaver knees were positioned with the ACL oriented along the loading axis and being the only connection between femur and tibia. 15° knee flexion was selected based on highest ACL tensions reported in literature. Therefore, the fixtures were adjusted accordingly to retain 15° knee flexion when the ACL was tensioned. The test protocol included 10 cycles of preconditioning between 6N and 60N at 1mm/s, followed by continuous distraction at 1mm/s until failure (Fig. 1). Eleven cadaveric knees (4 male, 7 female; 70.9 yrs +/−13.9 yrs) were tested using this setup to characterize a baseline ACL pullout strength (peak load to failure) in native knees. RESULTS. The average ACL pullout strength was 935.6N +/−327.5N with the extremes ranging from a minimum of 346N to a maximum of 1425N. There were five failure modes observed: [1] ACL avulsion from the femur with bony attachment (one knee), [2] ACL pull-off from the femur w/o bony attachment (two knees), [3] ACL tear (three knees), [4] ACL pull-off from the tibia w/o bony attachment (one knee), [5] ACL avulsion from the tibia with bony attachment (three knees). One knee showed a combined failure mode of 2 & 4, meaning part of the ACL was pulled off the femur and part pulled off the tibia. CONCLUSION. There was a large variation in failure load between specimens. The knee with the minimum failure load had severe arthritis, osteophytes and signs of ACL deficiency. The average failure load (935.6N +/−327.5N) is in line with those published in literature for a comparable age group. This indicates that failure loads and modes obtained with more complex setups could be reproduced by using standard uniaxial load frames and simple fixtures. The failure modes in our experiment were evenly spread between mid-substance, and insertions (either femur or tibia). This test could be used as a standardized method to investigate the strength of the ACL complex following procedures such as ACL reconstruction, partial- and total knee arthroplasty. In particular, this setup provides a reliable mechanism for evaluation of the ACL-bone construct in bi-cruciate retaining (BCR) TKA, which is likely required for regulatory pathways

Knee joint infection after an ACL reconstruction procedure is infrequently but might be a devastating clinical problem, if not diagnosed promptly and treated wisely. The results of functional outcomes in these patients are not well known because there aren't large patient series in the literature. The objective of this study was to evaluate the prevalence and determine the adequate management of septic arthritis following ACL reconstruction and to assess the patient functional outcomes. The authors conducted a retrospective multicentric analysis of septic arthritis cases occurring after arthroscopically assisted ACL reconstructions (hamstrings and BTB), in patients submitted to surgery between 2010 to 2014. The study reviewed patients submitted do ACL reconstruction, that presented objective clinical suspicion of joint infection, in post-operative acute and sub-acute phases, associated with high inflammatory seric parameters (CRP >=10,0, ESR>=30,0) and synovial effusion laboratory parameters highly suggestive (PMN >=80, leucocytes >=3000). All this patients were treated with antibiotic empiric suppressive therapy and then directed antibiotherapy according to antibiotic sensitivity profile, then the patients were submitted to arthroscopic lavage procedure, without arthropump, but with debris and fibrotic tissue removal preserving always the ACL plasty. The functional outcomes analyzed were the Lysholm and the IKDC score. Eleven (2.2 %) out of 490 patients analyzed in the sudy were diagnosed with a post-operative septic arthritis. The microbiologic exams showed coagulase-negative Staphylococcus was present in 5 patients (S. lugdunensis in 4 cases and S. capitis in 1 case), Staphylococcus Aureus in 2 patients (1 MSSA and 1 MRSA). In four patients, the micro-organism was not identified. The studied patients had a mean follow-up of 28 ± 16 months, the Lysholm score was 74.8 ± 12.2, the IKDC score was 66.4 ± 20.5. Functional outcomes in the control group were better than those obtained in the infected group. (Lysholm score 88.2 ± 9.4 (NS); IKDC score 86.6 ± 6.8 (NS). All patients retained their reconstructed ACL. None of the patients relapsed or need other intervention because of ACL failure and chronic instability. The prevalence of septic arthritis after an ACL reconstruction in this series was 2.2 %, slightly higher than other international series (0.14 to 1.7 %). Arthroscopic lavages along with antibiotic treatment showed to be a secure procedure and allowed the preservation of the ACL plasties, without infection relapse. But the functional outcomes after active intra-articular infection were largely inferior to those obtained in patients without infection, probably to uncontrolled and intense inflammatory local response

The level of hamstring antagonist activation is thought to be related to knee functionality following anterior cruciate ligament (ACL) injury/surgery as pronounced co-activation can control anterior tibial translation (ATT). The purpose of this study was to examine relationships between knee functionality and hamstring antagonist activation during isokinetic knee extension in ACL deficient (ACLD) and ACL reconstructed (ACLR) patients. Knee functionality was rated using the Cincinnati Knee Rating System for the involved limb of 10 chronic, functional ACLD patients and 27 ACLR patients (14 using a patella tendon (PT) graft and 13 using a semitendinosus/gracilis tendon (STGT) graft). Each subject also performed maximal effort isokinetic knee extension and flexion at 180°. s. -1. for the involved limb with electromyographic (EMG) electrodes attached to the semitendinosus (ST) and biceps femoris (BF) muscles. Antagonist activity of the ST and BF muscles was calculated in 10° intervals between 80-10° knee flexion. For the ACLD group, Pearson product moment correlations revealed significant (p<0.05) moderate, positive relationships between knee functionality and ST and BF antagonist activity across the majority of the knee flexion intervals. For both ACLR groups, several significant (p<0.05) moderate, negative associations were found between ST and BF antagonist activity and knee functionality. Amplified hamstring antagonist activity in ACLD patients at flexion angles representative of those at footstrike and deceleration improves knee functionality as increased crossbridge formation increases hamstring stiffness and decreases ATT. Lower-level hamstring activation is sufficient to unload the ACL graft and improve knee functionality in ACLR patients

One of the key factors responsible for altered kinematics and joint stability following contemporary total knee arthroplasty (TKA) is resection of the anterior cruciate ligament (ACL). Therefore, retaining the ACL is often considered to be the “holy grail” of TKA. However, ACL retention can present several technical challenges, and in some cases may not be viable due to an absent or non-functional ACL. Therefore, the goal of this research was to investigate whether substitution of ACL function through an anterior post mechanism could improve kinematic deficits of contemporary posterior cruciate ligament (PCL) retaining (CR) implants. This was done using KneeSIM, a previously established dynamic simulation tool based on an Oxford-rig setup. Deep knee bend, chair-sit, stair-ascent and walking were simulated for a contemporary ACL sacrificing (CR) implant, two ACL retaining implants, and an ACL substituting and PCL retaining implant. The motion of the femoral condyles relative to the tibia was recorded for kinematic comparisons. Our results revealed that, like ACL retaining implants, the ACL substituting implant could also provide kinematic improvements over contemporary ACL sacrificing implants by reducing early posterior femoral shift and preventing paradoxical anterior sliding. Such ACL substituting implants may be a valuable addition to the armament of joint surgeons, allowing them to provide improved knee function even when ACL retention is not feasible. Further research is required to investigate this mechanism in vitro and in vivo to verify the results of the simulations, and to determine whether kinematic improvements translate into improved clinical outcomes

Background. Anterior cruciate ligament (ACL) reconstruction with concomitant meniscal injury occurs frequently. Meniscal repair is associated with improved long-term outcomes compared to resection but is also associated with a higher reoperation rate. Knowledge of the risk factors for repair failure may be important in optimizing patient outcomes. Purpose. This study aimed to identify the patient and surgical risk factors for meniscal repair failure, defined as a subsequent meniscectomy, following concurrent primary ACL reconstruction. Methods. Data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation, the New Zealand Government's sole funder of ACL reconstructions and any subsequent surgery, was reviewed. Meniscal repairs performed with concurrent primary ACL reconstruction was included. Root repairs were excluded. Univariate and multivariate survival analysis was performed to identify the patient and surgical risk factors for meniscal repair failure. Results. Between 2014 and 2020, a total of 3,024 meniscal repairs were performed during concurrent primary ACL reconstruction (medial repair = 1,814 and lateral repair = 1,210). The overall failure rate was 6.6% (n = 201) at a mean follow-up of 2.9 years, with a failure occurring in 7.8% of medial meniscal repairs (142 out of 1,814) and 4.9% of lateral meniscal repairs (59 out of 1,210). The risk of medial failure was higher in patients with a hamstring tendon autograft (adjusted HR = 2.20, p = 0.001), patients aged 21–30 years (adjusted HR = 1.60, p = 0.037) and in those with cartilage injury in the medial compartment (adjusted HR = 1.75, p = 0.002). The risk of lateral failure was higher in patients aged ≤ 20 years (adjusted HR = 2.79, p = 0.021) and when the procedure was performed by a surgeon with an annual ACL reconstruction case volume of less than 30 (adjusted HR = 1.84, p = 0.026). Conclusion. When performing meniscal repair during a primary ACL reconstruction, the use of a hamstring tendon autograft, younger age and the presence of concomitant cartilage injury in the medial compartment increases the risk of medial meniscal repair failure, whereas younger age and low surgeon volume increases the risk of lateral meniscal repair failure

Purpose. Patients with anterior cruciate ligament (ACL) deficiency and symptomatic medial compartment osteoarthritis (OA) present a challenge in management. These are often younger than typical primary OA patients and aspire to remain athletically active beyond simple ADLs. Combined ACL reconstruction and valgus tibial osteotomy (ACLHTO) is a well documented surgical option for patients deemed wither too young or too active for total knee arthroplasty. Unicompartmental knee arthroplasty (UKA) is an established surgical treatment for symptomatic medial osteoarthritis of the knee refractory to conservative management. A commonly cited contraindications is symptomatic ACL deficiency because of previous reports detailing premature failure through loosening of the tibial component. Improved results and endoscopic ACL reconstructive procedures have led to an enticing concept of combining ACL reconstruction with medial unicompartmental knee arthroplasty (ACLUKR) for those ACL-deficient medial osteoarthritic (OA) knees. We sought to compare the outcomes in 2 cohorts of patients who underwent either ACLHTO or ACLUKR for this clinical problem. Method. Patients presenting with symptomatic bone on bone medial compartment OA and concomitant ACL deficiency (clinical or asymptomatic) were evaluated for surgery after exhausting non operative management. Patients who were under 40 or had plans to return to high impact loading sports and/or who had more moderate OA were offered combined ACL – medial opening wedge tibia osteotomy as a surgical procedure of choice. Patients were considered for combined ACL Oxford replacement if they were primarily seeking pain relief and were not engaged or aspiring to return to high impact or pivoting sports. All cases but one were concurrent ACL with either HTO or UKR with autogenous hamstring grafts used in all but 2 cases. Results. Thirty of 34 consecutive cases were available for follow-up for a rate of 88%. The median ages for 14 cases of ACLUKR was 51 (range 43 60) whereas 16 patients with ACLHTO had median age 43.4 (range 32 −59). Median FU was 4.65 yrs with minimum 2 year follow up (range 2–8.3). Three of the cases were revision ACL cases all from previous Gore-Tex reconstructions. All but the first patient had concomitant ACL and Oxford unicompartmental knee replacement at 1 surgical sitting and are the subject of this report. The first patient had an autogenous patella bone tendon bone graft performed 6 months prior to the UKA. There were similar change scores for patients in both groups. For ACLUKR, WOMAC pain improvements from 48.1 10.2 SD preoperatively to 79.0 17 SD postop. For ACLHTO, WOMAC improvements from 55.1 13.2 SD preoperatively to 85.0 17 SD postop. To date there have been no cases of infection or bearing dislocation in the ACLUKR group. One patient in the ACLHTO group was revised to TKR for ongoing pain and postoperative flexion contracture. Patient activities ranged from ambulation to vigorous hiking, tennis, and downhill skiing in the UKR group whereas a few in the ACLHTO group were also running mid distances. Overall satisfaction was similar in both groups. Conclusion. ACL reconstruction can safely be combined with medial UKR. The procedure has been used in younger patients with a view toward bone preservation while anticipating need for future revision. Both cohorts showed similar improvements and can be considered. The choice should be geared toward patient athletic demand. While short term results are encouraging though longer term data are necessary to thoroughly evaluate the role of this procedure in patients with medial compartment osteoarthritis and ACL deficiency

INTRODUCTION. In native knees anterior cruciate ligament (ACL) and asymmetric shape of the tibial articular surface with a convex lateral plateau are responsible for differential medial and lateral femoral rollback. Contemporary ACL retaining total knee arthroplasty (TKA) improves knee function over ACL sacrificing (CR) TKA; however, these implants do not restore the asymmetric tibial articular geometry. This may explain why ACL retention addresses paradoxical anterior sliding seen in CR TKA, but does not fully restore medial pivot motion. To address this, an ACL retaining biomimetic implant, was designed by moving the femoral component through healthy in vivo kinematics obtained from bi-planar fluoroscopy and sequentially removing material from a tibial template. We hypothesized that the biomimetic articular surface together with ACL preservation would better restore activity dependent kinematics of normal knees, than ACL retention alone. METHODS. Kinematic performance of the biomimetic BCR design (asymmetric tibia with convex lateral surface), a contemporary BCR implant (symmetric shallow dished tibia) and a contemporary CR implant (symmetric dished tibia) was analyzed using KneeSIM software. Chair-sit, deep knee bend, and walking were analyzed. Components were mounted on an average bone model created from magnetic resonance imaging (MRI) data of 40 normal knees. Soft-tissue insertions were defined on the average knee model based on MRI data, and mechanical properties were obtained from literature. Femoral condyle center motions relative to the tibia were tracked to compare different implant designs. RESULTS. During simulated chair-sit, the biomimetic BCR implant showed knee motion similar to that reported for healthy knees in vivo including medial pivot rotation with greater rollback of the lateral femoral condyle (5 mm medial vs. 11 mm lateral). The CR implant showed posterior femoral subluxation in extension, paradoxical anterior sliding until 60° flexion followed by limited rollback until 105° with no medial pivot rotation. The conventional BCR implant reduced initial posterior shift of the femur in extension, however, medial pivot rotation and steady posterior rollback was not achieved. Similar trends were also found for deep knee bend activity. During walking the CR implant showed posterior subluxation in extension followed by anterior motion similar to the chair-sit activity. Both BCR implants showed less femoral excursion without posterior subluxation similar to published in vivo kinematics data for bi-uni patients. CONCLUSION. By simulating a variety of daily activities with different ranges of knee motion we were able to show that the ACL preserving biomimetic TKA implant could restore activity dependent normal knee kinematics unlike contemporary ACL retaining and ACL sacrificing implants. For chair-sit activity there was a clear medial pivot pattern for the biomimetic BCR design (unlike any other implant), while for lower flexion activities there was no medial pivot apparent in our simulations. These activity dependent knee motions are consistent with published in vivo kinematics and confirmed our hypothesis that biomimetic articular surface together with ACL preservation may be required to restore normal knee function. The biomimetic BCR design with its anatomical articular surface together with ACL preservation may provide patients with a more normal feeling knee following TKA surgery

Anthropometric anatomical factors may influence mechanical and functional stability of joints. An increased posterior tibial slope places the anterior cruciate ligament at a theroretical biomechanical disadvantage. An increased posterior tibial slope can potentially alter forces during landing tasks by either increasing anterior tibial translation and/or ACL loading. The purpose of this study is to investigate the relationship between posterior tibial slope and anterior cruciate ligament injuries. It is hypothesised that subjects with an ACL injury have an increased posterior tibial slope compared to a normal population. Posterior tibial slope in 211 patients (154 male, 57 female), aged 15–49, who underwent anterior cruciate ligament reconstruction was measured using the posterior tibial cortex as reference. A matched control group was used for comparison. The average posterior tibial slope in the ACLR population was 6.1 degrees, whilst the control group had average values of 5.4 degrees. This finding nearly reached statistical significance (p=0.057). In the male population, average values were 5.5 degrees in the ACLR group and 5.9 in the control group. This was not significant (p=0.21). However, there was a significant difference (p=0.04) in the female group. ACLR females had higher values 6.5 degrees whereas the control group had average values of 5.2 degrees. Increased posterior tibial slope decreases the inclination of the ACL and potentially decreases vector force during dynamic tasks. We could not confirm the results of previous studies demonstrating an increased degree of posterior tibial slope in ACL injured patients. However, we demonstrated a significant difference in tibial slope in females. Based on our results, an increased posterior tibial slope is not a risk factor in males but possibly contributes to ACL injuries in females. Increased posterior tibial slope may be one of the reasons why females have a higher incidence of ACL injuries

Controversies about the management of injuries to the soft tissue structures of the posteromedial corner of the knee and the contribution of such peripheral structures on rotational stability of the knee are of increasing interest and currently remain inadequately characterised. The posterior oblique ligament (POL) is a fibrous extension off the distal aspect of the semimembranosus that blends with and reinforces the posteromedial aspect of the joint capsule. The POL is reported to be a primary restraint to internal rotation and a secondary restraint to valgus translation and external rotation. Although its role as a static stabiliser to the medial knee has been previously described, the effect of the posterior oblique ligament (POL) injuries on tibiofemoral stability during Lachman and pivot shift examination in the setting of ACL injury is unknown. The objective of this study was to quantify the magnitude of tibiofemoral translation during the Lachman and pivot shift tests after serial sectioning of the ACL and POL. Eight knees were used for this study. Ligamentous constraints were sequentially sectioned in the following order: ACL first, followed by the POL. Navigated mechanised pivot shift and Lachman examinations were performed before and after each structure was sectioned, and tibiofemoral translation was recorded. Lachman test: There was a mean 6.0 mm of lateral compartment translation in the intact knee (SD = 3.3 mm). After sectioning the ACL, translation increased to 13.8 mm (SD = 4.6; P<0.05). There was a nonsignificant 0.7 mm increase in translation after sectioning the POL (mean = 14.5 mm; SD = 3.9 P>0.05). Mechanised pivot shift: Mean lateral compartment translation in the intact knee was −1.2 mm (SD = 3.2 mm). Sectioning the ACL caused an increase in anterior tibial translation (mean = 6.7 mm; SD = 3.0 mm; P<0.05). No significant change in translation was seen after sectioning the POL (mean = 7.0 mm, SD = 4.0 mm; P>0.05). Sectioning the POL did not significantly alter tibiofemoral translation in the ACL deficient knee during the Lachman and pivot shift tests. This study brings into question whether injuries to the POL require reconstruction in conjunction with ACL reconstruction. More studies are needed to further characterise the role of the injured POL in knee stability and its clinical relevance in the ACL deficient and reconstructed knee

Controversies about the management of injuries to the soft tissue structures of the posteromedial corner of the knee and the contribution of such peripheral structures on rotational stability of the knee are of increasing interest and currently remain inadequately characterised. The posterior oblique ligament (POL) is a fibrous extension off the distal aspect of the semimembranosus that blends with and reinforces the posteromedial aspect of the joint capsule. The POL is reported to be a primary restraint to internal rotation and a secondary restraint to valgus translation and external rotation. Although its role as a static stabiliser to the medial knee has been previously described, the effect of the posterior oblique ligament (POL) injuries on tibiofemoral stability during Lachman and pivot shift examination in the setting of ACL injury is unknown. The objective of this study was to quantify the magnitude of tibiofemoral translation during the Lachman and pivot shift tests after serial sectioning of the ACL and POL. Eight knees were used for this study. Ligamentous constraints were sequentially sectioned in the following order: ACL first, followed by the POL. Navigated mechanised pivot shift and Lachman examinations were performed before and after each structure was sectioned, and tibiofemoral translation was recorded. Lachman test: There was a mean 6.0 mm of lateral compartment translation in the intact knee (SD = 3.3 mm). After sectioning the ACL, translation increased to 13.8 mm (SD = 4.6; P<0.05). There was a nonsignificant 0.7 mm increase in translation after sectioning the POL (mean = 14.5 mm; SD = 3.9 P>0.05). Mechanised pivot shift: Mean lateral compartment translation in the intact knee was −1.2 mm (SD = 3.2 mm). Sectioning the ACL caused an increase in anterior tibial translation (mean = 6.7 mm; SD = 3.0 mm; P<0.05). No significant change in translation was seen after sectioning the POL (mean = 7.0 mm, SD = 4.0 mm; P>0.05). Sectioning the POL did not significantly alter tibiofemoral translation in the ACL deficient knee during the Lachman and pivot shift tests. This study brings into question whether injuries to the POL require reconstruction in conjunction with ACL reconstruction. More studies are needed to further characterise the role of the injured POL in knee stability and its clinical relevance in the ACL deficient and reconstructed knee

A group of Athletes with torn ACL (insufficient knees) suffer from bowleg or valgus knees. AT this points we don't have a general consensus in literature. This study is based on a randomized clinical trial with double blind randomization of young athletes not more than 36 years and not over than 82 kg weight. Each groups contained by 30 patient with ACL deficient knees and bowlegs with Mikolicz line on the most medical 1/3rd of medial condyle of femur on worse. with follow up of 2 to 6 years and in all three groups we tried to control the knee by KT 2000, Tegner's score and IKDC and lysholm's scores in all patient. At final exam we had chance to meet 29 patients with simultaneous HTO (open wedge + plate) and ACL – R and 26 patients with HTO 1st, and 6 months later for ACL – R and only 24 patients with ACL – R 1st, 6 patients of this group and a patient of HTO 1st didn't show for rest of their procedures. Conclusion: by P value (o.o1) Simultaneous ACL – R and HTO had higher rate of success and between two other groups except osteoarthritis out come in short period of time (2 – 6 years) HTO had better results than ACL –R 1st with P value of (0.05)

Previous Anterior Cruciate Ligament (ACL) reconstruction is currently a bar from entry to the Royal Marines and Royal Navy, whilst the British Army allows recruits to join if asymptomatic 18 months post ACL reconstruction. However current Royal Marines policy is to rehabilitate recruits who sustain an ACL disruption in training. We retrospectively analysed the rehabilitation times and pass out rate of Royal Marines who had an ACL disruption during recruit training over an 8 year period. 12 recruits sustained an ACL disruption during recruit training in the study period, giving an incidence of around 1.5/1000 recruits. 9 Patients underwent ACL repairs in training, with 1 patient leaving and rejoining post repair and later successfully passed out. 2 patients were treated conservatively. Of the 12 ACL sustained in training 8/12 (67%) passed out. None of the patients treated conservatively passed out. The mean time out of training for successful recruits was 51.6 weeks (95% CI 13.1) mean rehabilitation time post ACL reconstruction for successful recruits was 36.7 weeks (95% CI 12.5). Mean time to discharge for unsuccessful recruits 63.2 weeks (95% CI 42.4). In the operative group 1/10 left due to failure to return to training and 1/10 left through unrelated reasons. Current costing for recruit training is £1800 per week per recruit. ACL injuries are not common in Royal Marine Training, and reconstruction is not a bar to completing Royal Marine basic training. We estimate that it costs around £100,000 per-injured recruit, to maintain a policy of rehabilitating ACL injured recruits in Royal Marines training. Further research into the long-term employability or Royal Marines sustaining an ACL injury in training is required

Given their role in reducing anterior tibial translation, the recruitment patterns and viscoelastic properties of the hamstring muscles have been implicated as neuromuscular factors contributing to the ACL gender bias. Nevertheless, it is uncertain whether patterns of aberration displayed by the female neuromuscular system significantly alters the antagonist moments generated by the hamstrings during maximal effort knee extension. The purpose of the current study was to examine the effect of gender on hamstring antagonist moments in order to explain the higher ACL injury rates in females. Eleven females (age 30.6 ± 10.1 years, mass 62.1± 6.9 kg, height 165.9 ± 4.6) and 11 males (age 29.0 ± 8.2 years, mass 78.6± 14.4 kg, height 178.5± 6.2) were recruited as subjects. Surface electrodes were placed over the semitendinosus (ST) and biceps femoris (BF) muscles of the dominant and non-dominant limbs. Each subject performed two sets of five maximal extension and flexion repetitions at 180-1. EMG, isokinetic torque and knee displacement data were sampled at 1000Hz using an AMLAB data acquisition system. Average hamstring antagonist torque data across the range of knee flexion for female subjects was significantly higher (%Diff=24%) than for the male control subject. Statistical analyses revealed a significant main effect of gender (F = 4.802; p = 0.036). Given that females possess a more compliant ACL and hamstring musculature, compared with their male counterparts, an augmented hamstring antagonist may represent a compensatory neuromuscular strategy to increase knee stiffness to control tibial translation and ACL strain. The results of this project suggest that it is unlikely that gender-related differences in hamstring antagonist torque is one of the predisposing factors contributing to the higher ACL injury rates in females

Separation of the ACL into anteromedial (AM) and posterolateral (PL) fibre bundles has been widely accepted. The bundles act synergistically to restrain anterior laxity throughout knee flexion, with the PL bundle providing the more important restraint near extension and its obliquity better restraining tibial rotational laxity. 10% of ACL injuries involve isolated rupture to one of these bundles causing patients to present with instability symptoms or pain. As knowledge about the influence of the ACL bundles on knee kinematics has increased, isolated reconstruction of either PL or AM bundle has been advocated. However only one cohort study of 17 patients has been presented in the clinical literature. KOOS (Knee Injury and Osteoarthritis Outcome Score) and IKDC (International Knee Documentation Committee Form) scores at 1yr post op were obtained for 12 patients who had undergone isolated ACL augmentation between 2007 and 2009. These were compared with previously published outcome scores for standard ACL reconstruction procedures. In addition examination under anaesthesia (EUA) assessments were analysed to see if a pattern of laxity for isolated AM and PL rupture could be determined. There were 5 patients with isolated AM bundle rupture and 7 with isolated PL bundle rupture. EUA analysis demonstrated that patients with isolated PL bundle rupture had increased pivot shift and Lachman test laxity, whereas the AM bundle rupture group had increased laxity with the anterior drawer test. Compared to previously published IKDC scores, there were no difference between isolated bundle augmentation and standard ACL reconstruction. However the KOOS scores showed significantly increased Sports function scores which was significantly better in the isolated bundle augmentations (93/100 v's 74/100). Differences between isolated AM and PL bundle reconstructions were not distinguishable. Isolated ACL bundle tears make up a significant proportion ACL injuries. Although technically more difficult than standard ACL reconstruction, isolated bundle augmentation appears to result in improved sports function when compared to standard ACL reconstruction

Meniscal tears commonly co-occur with ACL tears, and many studies address their side, pattern, and distribution. Few studies assess the patient's short-term functional outcome concerning tear radial and circumferential distribution based on the Cooper et al. classification. Meniscal tears require primary adequate treatment to restore knee function. Our hypothesis is to preserve the meniscal rim as much as possible to maintain the load-bearing capacity of the menisci after meniscectomy.

The purpose of this study is to document the location and type of meniscal tears that accompany anterior cruciate ligament (ACL) tears and their effect on patient functional outcomes following arthroscopic ACL reconstruction and meniscectomy.

This prospective cross-sectional observational study was conducted at AL-BASRA Teaching Hospital in Iraq between July 2018 and January 2020 among patients with combined ipsilateral ACL injury and meniscal tears. A total of 28 active young male patients, aged 18 to 42 years, were included. All patients were subjected to our questionnaire, full history, systemic and regional examination, laboratory investigations, imaging studies, preoperative rehabilitation, and were followed by Lysholm score 6 months postoperatively.

All 28 patients were males, with a mean age of 27 ± 0.14 years. The right knee was the most commonly affected in 20/28 patients (71.4%). The medial meniscus was most commonly injured in 11 patients, 7 patients had lateral meniscal tears, and 10 patients had tears in both menisci. The most common tear pattern of the medial meniscus was a bucket handle tear (36.4%), while longitudinal tears were the most frequent in the lateral meniscus (71.4%) (P-value = 0.04). The most common radial tear location was zone E-F (5/28, 17.8%), and the most common circumferential zone affected was the middle and inner third, reported in 50% of tears. Good and excellent outcomes using the Lysholm score after 6 months were obtained in 42.9% and 17.9% of patients, respectively. Better functional scores were associated with lateral meniscal tears, bucket handle tears, tears extending to a more peripheral vascular area, and if no more than one-third of the meniscus was resected (P-value = 0.002). Less favourable outcomes were reported in smokers, posterior horn tears, and when surgery was delayed more than 1 year (P-value = 0.03).

We conclude that there is a negative correlation between the amount of meniscus resected and functional outcome. Delayed ACL reconstruction increases the risk of bimeniscal tears. Bucket handle tears are the most common tears, mostly in the medial meniscus, while longitudinal tears are most common in the lateral meniscus. We recommend performing early ACL reconstruction within 12 months to reduce the risk of bimeniscal injuries.

Introduction. The anterior cruciate ligament (ACL) is one of the most common ligament injuries. Several ACL reconstructions exist and are consequently performed. An accurate and comprehensive description of knee motion is essential for an adequate assessment of these surgeries, in terms of restoring knee motion. Methods. We propose to compare these reconstructions thanks to an index of articular coherence. This index measures the instantaneous state surface configurations during a motion. More specifically, this refers to the position between two articular surfaces facing each other. First of all, the index has to refer to a position known to be physiological. This initial position of the bones, named reference, directly results from the segmentation of CT scans. First we compute all distances between the two surfaces and then we compute the Cumulative Distribution Function (CDF). We process this way for each iteration of the motion. Then we obtain a batch of CDF curves which provide us qualitative information relative to the motion such as potential collisions or dislocations. The graph of all CDF curves is called Figure of Articular Coherence (FoAC). A good articular coherence is characterised by CDF which are close to the reference. This qualitative method is coupled to a quantitative one named Index of Articular Coherence (IoAC) which computes the Haussdorff distance between the temporal distributions and the reference. This distance has to be as low as possible. The tools were tested on cadaveric experiments of ACL reconstruction provided by Hagemeister et al, (1999). They recorded the knee flexion/extension motion in following situations: the intact knee, after ACL resection, after three methods of ACL reconstruction on the same knee (‘over-the-top’ method (OTT), two different two tunnel reconstructions (2 tunnel). Our method was used, for the time being, for one specimen. We compare different post-surgery kinematics thanks to the FoAC and IoAC. Results and discussion. Functions were well correlated to the reference, when considering flexion motion of the intact knee. Regarding the results of the FoAC after ACL resection, we observed that the functions evolve in the direction of decreasing distances more rapidly, compared to the intact knee. This means that both articular surfaces are close to collision when ACL is resected. Regarding the results of the IoAC for the different experimental situations, we observe that the highest index is obtained for the ACL resected knee. The OTT method has equivalent results to the intact knee and for both 2 tunnels reconstructions, the index values are higher than those obtained with the intact knee. This higher index can be explained by an over-constraint on the knee movement, the knee appears to be more stable but it can possibly rigidify the joint as well. Through the use of the FoAC and IoAC, we reached the same conclusions of Hagemeister's work in a way that is more intuitive than by using kinematic curves and angle values. Our tools can describe the instantaneous state of the joint and are able to compare kinematics corresponding to different types ACL reconstructions

Aim. The aim of this study is to outline the steps and techniques required to create a patient specific 3D printed guide for the accurate placement of the origin of the femoral tunnel for single bundle ACL reconstruction. Introduction. Placements of the femoral tunnels for ACL reconstruction have changed over the years 1,2. Most recently there has been a trend towards placing the tunnels in a more anatomic position. There has been subsequent debate as to where this anatomic position should be 3. The problem with any attempt at consensus over the placement of an anatomic landmark is that each patient has some variation in their positioning and therefore a fixed point for all has compromise for all, as it is an average 4. Our aim was to attempt to make a cost effective and quick custom guide that could allow placement of the center of the patients’ newly created femoral tunnel in the mid position of their contralateral native ACL femoral footprint. Materials & Methods. We took a standard protocol MRI scan of a patient's knee without ACL injury transferred the DICOM files to a personal computer running OsiriX (Pixmeo, Geneva, Switzerland.) and analyzed it for a series of specific anatomical landmarks (fig1). These measurements and points were then utilized to create a 3D computer aided design (CAD) model of a custom guide. This was done using the 3D CAD program 123Design (Autodesk Ltd., Farnbourgh, Hampshire). This 3D model was then uploaded to an online 3D printing service and the physical guide was created in transparent acrylic based photopolymer, PA220 plastic (fig 2) and 316L stainless steel. The models created were then measured using vernier calipers to confirm the accuracy of the final guides. The models produced were accurate with no statistical difference in size and positioning of the center of the ACL footprint from the original computer model and to the position of the ACL from the MRI scans. The costs for the models 3D printed were £3.50 for the PA220 plastic, £15 for the transparent photopolymer and £25 for the 316L stainless steel. The time taken from MRI to delivery for the physical models was 7 days. Conclusion. This study serves as the first step and a proof of concept for the accurate creation of patient specific 3D printed guides for the anatomical placement of the femoral tunnel for ACL reconstruction. The guides were easy to create and produce taking only a week and with a cost of between £3.50 and £25

Background The minimum size required for a successful quadrupled hamstring autograft ACL reconstruction remains controversial. The risks of ACL re-tear in younger patients who tend to participate in a higher level of sports activity, and female athletes who have numerous predisposing factors, are poorly defined. Purpose To identify risk factors for graft re-tears within 2 years of ACL surgery. The hypotheses are that female sex, a smaller size graft, and younger patients will increase the odds of failure. Study Design Cohort Study. Level of evidence, 3. A cohort of 503 athletes undergoing primary, autograft hamstring ACL reconstruction, performed by a single surgeon using the same surgical technique and rehabilitation protocol, between September-December 2012, was followed for a total duration of 2 years. Return to play was allowed between 6 and 12 months post-surgery upon completion of functional testing. Exclusion criteria included infections, revisions, double bundle techniques, multi-ligament injuries, non-compliance, BTB/allografts/hybrid grafts. Primary outcome consisted of binary data (ACL graft re-tear or no tear) as measured on physical exam (Lachman and pivot shift) and MRI. Multivariate logistic regression statistical analysis with model fitting was used to investigate the predictive value of sex, age, and graft size on ACL re-tear. Secondary sensitivity analyses were performed on the adolescent subgroup, age and graft size as categorical variables, and testing for interactions among variables. Sample size was calculated based on the rule of 10 events per independent variable for logistic regression. The mean age of the 503 athletes was 27.5 (SD 10.6; range = 12–61). There were 235 females (47%) and 268 males (53%) with a 6 % rate of re-tears (28 patients; 17 females). Mean graft size was 7.9 (SD 0.6; range = 6–10). Univariate analyses of graft size, sex, and age only in the model showed that younger age (odds ratio [OR] = 0.86; 95% confidence interval [CI] = 0.80–0.93; P = .001] and smaller graft size (OR = 0.36; 95% CI = 0.18–0.70; P = .003) were significantly predictive of re-tear. Female sex was correlated with re-tear but was not significant (OR = 1.8; 95% CI = 0.84–3.97; P = .13). Multivariate analysis with all 3 variables in the model showed similar significant results. Graft size < 8 mm (OR = 2.95; 95% CI = 1.33–6.53; P = .008) and age < 25 (OR = 7.01; 95% CI = 2.40–20.53; P = .001) were significantly predictive of re-tear. Entire model was statistically significant (Omnibus test P = .001; Hosmer-Lemeshow statistic P = .68; Receiver Operating Curve [ROC] = 0.8). Surgeons should counsel their patients who are female, younger than 25 and with a graft size less than 8 mm accordingly and consider modifying their surgical or rehabilitation techniques to mitigate these re-tear risks

Purpose. The majority (73%) of orthopaedic surgeons in Canada prefer using semitendinosus-gracilis (STG) autograft for ACL reconstruction. However, there is large variation in tendon size between individuals which makes pre-operative estimation of graft size unpredictable. Inadequate graft size may require an alternative source of graft tissue that should be planned prior to surgery. The purpose of this study is to determine if clinical anthropometric data and MRI measurements of STG tendons can be used to predict hamstring graft size. Method. One-hundred and fourteen patients with ACL deficiency awaiting reconstruction using hamstring autograft were retrospectively evaluated. The following information was obtained from patient charts: height, weight, body mass index (BMI), age, and gender. Cross-sectional area (CSA) of gracilis (G) and semitendinosus (ST) tendons were determined from pre-operative MRI scans using NIH ImageJ analysis software. Actual STG graft diameters were obtained from operative reports. Correlations between patient height, weight, BMI, age, gender, ST-CSA, G-CSA, STG-CSA and intraoperative graft size were calculated to determine the association between these variables. Multiple stepwise regression was performed to assess the predictive value of these variables to intraoperative graft diameter. In addition, three investigators with no radiological experience made independent measurements of the ST and G tendons to determine the inter-rater reliability (ICC) of MRI measurements. Results. All variables were independently correlated with intraoperative graft size (p<0.001). However, based on multiple stepwise regression analysis, only models including STG-CSA (r2=.212; p<.001); STG-CSA and sex (r2=.285; p<.001); and STG-CSA, sex and weight (r2=.294; p<.001) were found to be significant predictors of graft size (when co-variation in other factors was controlled). Inter-class correlation coefficients demonstrated very high agreement between raters for measurements of the ST, G and STG (.816, .827, .863, respectively). Conclusion. Measurement of tendon CSA from MRI images is very reliable. A model including STG-CSA, sex and weight was found to be strongly predictive of hamstring graft diameter for ACL reconstruction. This model may enhance our ability to predict adequate graft size and identify instances that other graft tissues may be a better option. The results of this study may improve pre-operative planning for ACL reconstruction

To determine the relationship between advancing months from ACL rupture and the incidence of intra-articular meniscal and chondral damage. From a prospectively collected database 5086 patients undergoing primary ACL reconstruction, using hamstring graft, carried out between January 2000 and August 2010 were identified. Data collected included the interval between injury and surgery, type and location of meniscal tears (requiring meniscectomy) and location and severity of chondral damage (ICRS grading system). Patients were grouped according to time interval and age. The median time from ACL injury to ACL reconstruction was 3 months (range 0.25 to 480). Overall, an increasing incidence of medial meniscal injury and chondral damage occurred with advancing chronicity of ACL deficiency. The incidence of medial meniscal injury requiring meniscectomy increased from 18% of patients undergoing ACL reconstruction within 4 months of injury to 59% of patients if ACL reconstruction was delayed more than 12 months (p<0.001). The incidence of lateral meniscal tears did not increase significantly over time. The increasing incidence of secondary pathology with advancing chronicity was more pronounced in the younger age groups. The risk of a medial meniscal tear requiring resection was significantly less if surgery was performed before 5 months in the <17 years group (Odds Ratio 2) and 17–30 years group (OR 1.9), but less so in the 31–50 years group (OR 1.5) and >50 years group (OR 1.5). Advancing age was associated with a greater incidence of chondral damage and medial meniscal injury, but not lateral meniscal injury. Males had a greater incidence of lateral meniscal tears (34% vs. 20%), but not medial (28% vs. 25%) or chondral damage (35% vs. 36%), compared to females. The incidence of chondral damage and medial meniscal tears increases with advancing time after ACL injury. Particularly in younger patients, ACL reconstruction should be performed within 4 months of ACL injury in order to minimise the risk of irreversible damage to meniscal and chondral structures