The effects of test environment and cyclic stretching on the failure properties of human patellar tendons

There is a need to document the mechanical properties of patellar tendon allografts used for reconstructive surgery of the damaged anterior cruciate ligament, especially the effects of irradiation sterilization. The purpose of this study was to investigate the influences of in vitro test environment and low-level cyclic stretching prior to failure tests on nonirradiated and irradiated human graft tissues. Bilateral patellar tendons were split and each half processed accordingly. Some graft tissues were stretched cyclically at 2.5 mm deformation before failure. Experiments were performed in a 37 degrees C saline bath or with tissues moistened with a drip of the same. The irradiated grafts relaxed less and generated less slack length in the drip environment than the nonirradiated controls. Cyclic stretching did not alter failure characteristics of either graft tissue. While no significant differences in the tensile responses or failure characteristics were noted for irradiated and nonirradiated grafts in the drip, in the bath environment the nonirradiated tissues had greater strength and modulus. This resulted in there being a significant difference between irradiated and nonirradiated tissue responses in a heated saline bath environment. These experimental results exemplify the need to control in vitro test environments in the evaluation of various sterilization and preservation protocols for soft tissue allografts.     

SLE患者抗磷脂抗体纵行观察的初步分析

本文对７４例ＳＬＥ患者ＩｇＧ－ＡＣＬ纵行观察四年，就其变化和临床相关性进行分析。３９例ＡＣＬ阳性组中３４例（８７％）的中等至严重活动性ＳＬＥ，而ＡＣＬ阴性组仅１３／３５（３７％）。ＡＣＬ阳性与ＳＬＥ疾病的活动性密切相关。ＡＣＬ阳性组在血栓形成、自发性流产、中枢神经系统损害、血小板下降方面均较ＡＣＬ阴性组有显著的差别。阳性ＡＣＬ组又可分为：持续ＡＣＬ阳性的Ａ组和ＡＣＬ有波动的Ｂ组。Ａ组患者较Ｂ组更容易发生血栓、抗磷脂抗体综合征，特别是脑血栓等中枢神经系统病变，这是ＡＣＬ持续阳性ＬＬＥ患者的临床特征之一。     

Long-term results of the Leeds-Keio anterior cruciate ligament reconstruction

This paper discusses the long-term results of the anterior cruciate ligament (ACL) reconstruction with the Leeds-Keio (LK) prosthetic ligament. For this type of reconstruction we used arthrotomy and an arthroscopy-assisted technique. The fixation was obtained with two bone plugs, and the distal portion was also attached with a staple. A postoperative protocol was used with a progressive range of motion and weight bearing after 50 days. We performed 50 LK operations in professional and amateur athletes aged 17–39 years with an isolated anterior instability. We reviewed at follow-up (5–7 years) 37 patients; 8 were lost, and 5 had a subsequent failure. At the Lysholm score the patients were classified: 19 excellent, 13 good, 3 fair, and 2 poor. At the IKDC grading the patients were classified as follows: 2 class A, 22 B, 8 C, and 5 D. The Lachman test was 1+ in 15 patients, 2+ in 7, 3+ in 2, and negative in 13: pivot shift was 1+ in 9, 2+ in 7, 3+ in 2, and negative in 25. Results of the KT 1000 test at 30 Ib side to side was <3 mm in 23 patients, 3–5 mm in 6, 6–10 mm in 6, and >10 mm in 2. In view of the results observed and the progressive deterioration over the years, this procedure should no longer be performed as an ACL substitute.     

跟腱重建前十字韧带术后康复治疗恢复膝关节功能的疗效分析

Inrecentyears，withtherapidpopularizationofarthroscopictechniquesandsuccessfulapplicationofallogenictissuegraft，wereconstructedACLusingallogenicachillestendonunderarthroscopybyisometricreestablishment，biologicalfixation．１Subjectandmethod１．１SubjectFromJanuary１９９６toJune２００１，３８patientswererecruited．Thesepatientsincluded３１men（３２lesions），３womenaged１８～３６yearswithmeanageof２４．３．Lesionsconsistedof１２leftinjuries，２１rightinjuries，１bilateralinjury．Causesofinj…     

Comparison between two techniques for surgical repair of the acutely torn anterior cruciate ligament

This prospective, randomized study was designed to evaluate the early outcome of ACL repair with biologic or synthetic augmentation. Fortyeight consecutive patients with an acute proximal rupture of the ACL were included. The repairs in 22 patients were augmented with the Kennedy Ligament Augmentation Device (LAD), while 26 patients received a repair augmented with an autologous bone-patellar tendon-bone graft. All patients followed a standard rehabilitation protocol. Follow-up evaluations at 1 and 2 years postoperatively were based on the Tegner activity level, Lysholm functional score, clinical instability tests and KT-1000 arthrometer measurements. There were no significant differences in activity level or functional score between the LAD and patellar tendon groups at the 2-year follow-up. Ten patients in the LAD group (46%) sustained reruptures of the ACL and LAD at the 2-year follow-up, while two patients in the patellar tendon group had a KT1000 side difference of 4 mm or more. However, none of the patients in the patellar tendon group had a positive pivot shift. During the first postoperative year, 8 patients (31%) in the patellar tendon and 2 in the LAD group (9%) underwent arthroscopic debridement for correction of an extension deficit. These range of motion complications were probably related to the anterior placement of the tibial tunnel and the conservative rehabilitation protocol. Because of the unacceptable high incidence of reruptures in the LAD group, we concluded that the augmentation technique with the LAD is unacceptable.     

Comparison of functional outcome after anterior cruciate ligament reconstruction resulting in low, normal and increased laxity

The aim of the study was to analyse and compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using patellar tendon autografts in three groups of patients. The groups were determined by knee laxity as measured with the KT-1000 arthrometer at the follow-up two to five years after the reconstruction. Group A (n=15) had an anterior side-to-side laxity difference of <-3 mm (i.e. the reconstructed knee was less lax than the contralateral non-injured knee), Group B (n=376) had a difference of > or = -1, but < or = +2 mm and Group C (n=38) had a difference of > or g=6 mm. All the patients had a normal contralateral knee. In Group A, 7/15 (47%) patients and, in Group B, 82/375 (22%) patients had an extension deficit of > or =5 degrees (P=0.052). The corresponding values in terms of flexion deficit were 8/15 (53%) and 99/375 (26%) respectively (P=0.04) (one missing value in Group B). In Group C, 14/38 (37%) had an extension deficit (P=0.04; Group B vs Group C). Group C displayed worse results than Group B in terms of the Lysholm score and the one-leg-hop test (P=0.001 and P=0.011 respectively). The corresponding comparison between Group A and Group B revealed no significant differences. We conclude that a considerable number of patients showed persisting deficits in range of motion (ROM) after an ACL reconstruction. No major differences were found if they were analysed in subgroups with decreased, near normal or with increased knee laxity. The worst residual functional impairment, as measured with the Lysholm score and one-leg-hop test, was found in the group with increased knee laxity and most ROM deficits in the knees with decreased laxity.     

Mechanism of quadriceps femoris muscle weakness in patients with anterior cruciate ligament reconstruction

The purpose of this study was to investigate gamma loop function in the quadriceps femoris muscle in patients who with less than 6 month-history of anterior cruciate ligament (ACL) reconstruction. For this purpose, we compared the response to vibration stimulation in 10 patients with ACL repair and 12 normal healthy subjects, by measuring the maximal voluntary isometric contraction (MVC) and integrated electromyograms (I-EMG) of the quadriceps muscles. Pre-vibration data were obtained from each subject by measuring the MVC of the knee extension and the I-EMG from the vastus medialis, vastus lateralis, and rectus femoris muscles. Vibration stimulation was applied to the infrapatellar tendons, followed immediately by repeating the MVC and I-EMG recording. Prolonged vibration resulted in a significant decrease of both MVC and I-EMG in the control group. In contrast, the same stimulus failed to elicit changes in ACL-repair group. Our results suggest the presence of abnormal gamma loop function in the quadriceps femoris muscle of patients with ACL repair, which may explain the muscle weakness often described in such patients.     

The Apoptosis Pathway and CASP8 Variants Conferring Risk for Acute and Overuse Musculoskeletal Injuries

Rotator cuff tendinopathy (RCT), anterior cruciate ligament (ACL) ruptures, and carpal tunnel syndrome (CTS), are examples of chronic (RCT and CTS) and acute (ACL ruptures) musculoskeletal soft tissue injuries. These injuries are multifactorial in nature, with several identified intrinsic and extrinsic risk factors. Previous studies have implicated specific sequence variants within genes encoding structural and regulatory components of the extracellular matrix of tendons and/ligaments to predispose individuals to these injuries. An example, includes the association of sequence variants within the apoptotic regulatory gene, caspase-8 (CASP8) with other musculoskeletal injury phenotypes, such as Achilles tendinopathy. The primary aim of this study was, therefore, to investigate previously implicated DNA sequence variants within CASP8: rs3834129 (ins/del) and rs1045485 (G/C), and the rs13113 (T/A) identified using a whole exome sequencing approach, with risk of musculoskeletal injury phenotypes (RCT, ACL ruptures, and CTS) in three independent studies. In addition, the aim was to implicate a CASP8 genomic interval in the modulation of risk of RCT, ACL ruptures, or CTS. It was found that the AA genotype of CASP8 rs13113 (T/A) was independently associated with increased risk for CTS. In addition, it was found that the del-C haplotype (rs3834129–rs1045485) was significantly associated with non-contact ACL ruptures, which is in alignment with previous research findings. Collectively, the results of this study implicate the apoptosis pathway as biologically significant in the underlying pathogenesis of musculoskeletal injury phenotypes. These findings should be repeated in larger sample cohorts and across different populations. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:680–688, 2020     

The use of a multi-modal approach in the rehabilitation of a pre-operative grade 3 ACL tear in a world-level Poomsae athlete: a case report

ObjectiveThis case is designed to aid practitioners in understanding the potential role of multi-modal care with vibration rehabilitative exercise for a complete ACL tear in a high-level Poomsae athlete.Case presentationA 16-year-old male world-class Poomsae athlete presented with a right ACL rupture and LCL sprain. An extensive clinical examination and imaging confirmed a right grade 3 ACL tear. Due to the complete tear and impending participation in World Championships, a pre-operative rehabilitation strategy was implemented with treatment modalities aimed to accelerate return-to-play.SummaryAn appropriate clinical history and physical examination of the knee is required when instability is present. Imaging is indicated when testing criteria are positive. Clinicians should be aware that multiple therapies can each serve a role in conservative care to better suit patient demands, especially at high levels of sport. In the article, the author proposes a tailored protocol using vibration rehabilitative exercise, bracing, vibration therapy, neuromuscular electrical stimulation, and laser to improve healing and sport-specific outcomes.