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PubMedDate not supplied

Arthroscopic identification of the popliteofibular ligament.

PURPOSE: The popliteofibular ligament has recently received recognition as a distinct structure with a significant contribution to posterolateral stability of the knee. The popliteofibular ligament plays a key role in stabilizing the posterolateral corner of the knee by limiting posterior translation, varus angulation, and external rotation (coupled and primary). During arthroscopic procedures, the senior author (R.D.P.) has observed vertically oriented fibers descending from the inferior surface of the intra-articular portion of the popliteus tendon at the popliteal hiatus. This study was performed to determine if these fibers were actually the popliteofibular ligament. TYPE OF STUDY: This is an anatomic study using a cadaveric knee model to identify the popliteofibular ligament both arthroscopically and through gross anatomic dissection. METHODS: Eight fresh human cadaveric knees were examined arthroscopically and the vertically oriented fibers from the inferior surface of the popliteus tendon at the popliteal hiatus were identified and marked with a suture using an arthroscopic suture passer. A dissection of the lateral side of the knee was then performed to identify the marked structure. RESULTS: In all specimens, the dissection revealed that the fibers identified and marked arthroscopically had firm attachments to the popliteus tendon superiorly and inserted distally into the posterior aspect of the fibular head. The labeled structure was, therefore, the popliteofibular ligament. The popliteofibular ligament bifurcated distally with 2 insertion sites onto the fibular head. CONCLUSIONS: From this study, we concluded that the vertically oriented fibers descending from the inferior surface of the intra-articular portion of the popliteus tendon at the popliteal hiatus identified during arthroscopy are indeed those of the popliteofibular ligament. It is hoped that this knowledge will lead to improved outcomes in the treatment of injuries to the posterolateral corner of the knee.

Adolescent↗
PubMedDate not supplied

[Sensorimotor potential of the intact and injured anterior and posterior cruciate ligaments--a neurophysiological study in an animal model].

AIM: This neurophysiological study is intended to investigate the sensomotor potential of the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) which may provide joint stabilization via a ligamentomuscular reflex arch. In addition, the role of ligamentous injury on the sensomotor potential has been investigated. METHOD: The sensomotor potential was investigated using 24 knee joints in a sheep model under in-vivo conditions. The cruciate ligaments were mechanically loaded and the muscular activities of the hamstrings and the quadriceps were recorded simultaneously via electromyography. Injury to the ligaments was simulated by defined mechanical elongation of the ACL and PCL to failure. RESULTS: The results confirm the hypothesis of the existence of a ligamentomuscular reflex loop between ligamentary mechanoreceptors and the joint-stabilizing muscles. Mechanical loading of the ACL triggered mainly the activity of the hamstrings, whereas loading of the PCL led to the activation of the quadriceps. The rate of elongation which caused disturbances to the sensomotor potential was significantly smaller as compared to the elongation to failure. CONCLUSION: The cruciate ligaments provide dynamic joint stabilization via a ligamentomuscular reflex arch. It was demonstrated that the sensomotor potential of both structures is significantly more susceptible to ligament injury than the biomechanical potential.

Animals↗
PubMed1999

Ligament tissue engineering using synthetic biodegradable fiber scaffolds.

Tissue engineering offers the possibility of replacing damaged human ligaments with engineered ligament tissues. Hence, we attempted to culture in vitro ligament tissues by seeding human anterior cruciate ligament (ACL) and medial collateral ligament (MCL) cells onto synthetic biodegradable polymer fiber scaffolds. The ACL and MCL cells readily attached to the scaffold fibers. These cells and their secreted matrix soon surrounded the scaffold fibers and bridged the gaps in between. Beginning at 2 weeks, portions of the scaffolds were completely filled with tissue matrix. By 5 weeks, the scaffolds became single bundles of tissue. Thus the cell/fiber system appears to be a viable system for culturing ligament tissues. Additionally, cell proliferation under mechanical and biochemical stimuli was studied for up to 4 days. Whereas mechanical stimulus and transforming growth factor enhanced proliferation, inflammatory agents (lipopolysaccharide and complement C5a) had a negative effect. This work can thus contribute to a sound strategy for culturing replacement ligament tissues in vitro.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Meniscal injuries associated with acute anterior cruciate ligament tears in alpine skiers.

We reviewed the records of 315 patients receiving an arthroscopically assisted stabilizing procedure for an acute anterior cruciate ligament injury incurred while alpine skiing to evaluate associated meniscal injuries. Meniscal injuries were classified by type, location, and treatment of the tear. Of the 317 knees operated on, all demonstrated an anterior cruciate ligament tear at arthroscopy. Ninety-eight percent of the injuries (310) were diagnosed within 3 days of injury, and 97% (307) were reconstructed within 28 days of injury. All tears occurred in the intrasubstance of the ligament; 32% were isolated injuries and 68% were combined with other injuries. In 159 patients with 170 meniscal tears 141 of the tears (83%) were lateral and 29 (17%) were medial. The injury triad of anterior cruciate ligament-medial collateral ligament-lateral meniscus was seen nine times as often as the anterior cruciate ligament-medial collateral ligament-medial mensicus combination.

Acute Disease↗
PubMedDate not supplied

Comparison between magnetic resonance imaging findings and knee stability: measurements after anterior cruciate ligament repair with and without augmentation. A five- to seven-year followup of 52 patients.

We compared magnetic resonance imaging findings with knee stability measurements in a group of 52 patients 5 to 7 years after repair of an acute anterior cruciate ligament rupture. The patients underwent one of three surgical procedures: nonaugmented repair using the Palmer technique, repair with synthetic augmentation, and repair with biologic augmentation. The appearances of the menisci, subchondral bone, and cartilage were also assessed. Of the patients with clinically stable knees in the nonaugmented repair group, the repaired ligament appeared to be present and intact in 54% (7 of 13) of the patients. In the group with the repair augmented with the ligament augmentation device, 33% (4 of 12) demonstrated repair integrity, whereas in the group with patellar tendon augmentation of the repair, 82% (14 of 17) of the patients with clinically stable knees had intact ligaments on magnetic resonance imaging. Twelve patients had new and complete ruptures of one of the menisci, nine of which occurred in unstable knees. Thirteen patients had subcortical bone changes in the femoral condyles. Eight of these knees had major degenerative cartilage changes overlying the bone changes. Magnetic resonance imaging signals in the repaired ligament augmented with the patellar tendon were highly predictive of clinical stability, but the integrity of the nonaugmented and ligament augmentation device-augmented anterior cruciate ligament repairs did not closely correlate with the clinical findings.

Adolescent↗
PubMed1994

Use of allografts after failed treatment of rupture of the anterior cruciate ligament.

A prospective study was done of the use of allogeneic tissue to reconstruct the anterior cruciate ligament in knees in which an intra-articular or an extra-articular operation had failed. Sixty-six consecutive patients (sixty-six knees) had such an operation with use of bone-patellar ligament-bone allografts; all but one returned for follow-up evaluation twenty-three to seventy-eight months (mean, forty-two months) after the operation. A total of 235 previous operations had been performed in these sixty-six knees, including eighty-one procedures for rupture of the anterior cruciate ligament. The results of the allograft procedure were evaluated with a subjective and objective system that rated twenty factors. The anterior-posterior displacement was substantially improved in most of the patients. According to data derived from arthrometric studies and pivot-shift tests of the fifty-seven patients who were so evaluated and in whom the condition was unilateral, 53 per cent (thirty) of the reconstructed ligaments were determined to be functional; 21 per cent (twelve ligaments), partially functional; and 26 per cent (fifteen ligaments), a failure. When we calculated the rate of failure by including ten failures that had occurred within two years after the operation with the fifteen that occurred in patients who had been followed for at least two years, the over-all rate of failure was 33 per cent (twenty-five of seventy-five operations). There was significant improvement in the subjective ratings of functional limitations and symptoms (p < 0.01) and in the over-all rating score (p < 0.0001). However, there was a significant difference between the scores of the patients in whom the surfaces of the articular cartilage had appeared normal at the index operation and those of the patients in whom there had been noteworthy fissuring and fragmentation or exposure of subchondral bone. After the program of rehabilitation, which included immediate motion of the knee, a range of motion of 0 to 135 degrees was restored in all but five knees, four of which lacked only 5 degrees of this extent of flexion or extension. The results demonstrate that bone-patellar ligament-bone allografts may be used when proper autogenous tissues are not available and that symptoms and abnormal displacement were reduced in most of our patients.

Activities of Daily Living↗
PubMed1994

Anterior cruciate ligament mechanoreceptors. Histologic studies on lesions and reconstruction.

The fate of mechanoreceptors was studied in torn and reconstructed anterior cruciate ligaments in animals and in humans. In untreated anterior cruciate ligament lesions in humans, morphologically normal mechanoreceptors remained in the ligament for 3 months after the injury. After that time, their number gradually decreased. By the 9th postinjury month, only a few free nerve endings were present. Even free nerve endings were totally absent in the biopsy specimens from 1-year-old lesions. In experimental animals, anterior cruciate ligament reconstruction with autologous patellar tendon resulted in the presence of mechanoreceptors in the reconstructed anterior cruciate ligament. When an artificial ligament was used, no mechanoreceptors were found. Morphologically normal mechanoreceptors were present in 2 patients with a lax biologic anterior cruciate ligament reconstruction 9 and 10 years after the operation.

Animals↗
PubMed1996

Scapho-lunate dissociation and arthrodesis. An experimental study with lesions of the interosseous ligament and fusions with K-wires.

The carpal mechanism is studied during a sectioning of the ligament between the lunate and the scaphoid. A tear in this ligament is frequently observed in the clinic. After experimental lesions of this ligament, some authors say there is little effect while others report significant changes. We have conducted repetitions of these sectioning experiments using roentgen stereophotogrammetry to assess the kinematics of the carpal bones. We have found very little effect. We have also fused the scaphoid to the lunate to find out what happens to the carpal mechanism when the ligament between these bones is made stiffer. Fusion is carried out with K-wires and the effect upon the carpal mechanism is studied again. Our K-wiring of the scaphoid and lunate shows that the carpus starts to behave unpredictablely. The positions of the wires influence the outcome significantly. RELEVANCE--:The ligament between the scaphoid and the lunate has been assigned a main function in the carpal mechanism. It is still in debate, however, whether a lesion of this ligament by itself leads to the typical scapho-lunate dissociation pattern of the carpus. We have shown that a disruption of this ligament hardly influences the carpal mechanism. In time though, other ligaments may become overstretched so that finally the typical pattern may show up. K-wiring of the lunate and scaphoid to restore the connection between these bones results in a primarily unstable joint.

Journal Article↗
PubMed1995

In-vitro correlation between tension and length change in an anterior cruciate ligament substitute.

The length change and tension patterns from multiple insertion locations of an anterior cruciate ligament substitute were studied in 10 cadaver knees. Length change was measured with a spring-loaded isometer of low stiffness, and tension was measured with a piezoelectric load cell. In both instances a thin Kevlar test ligament was positioned in five different femoral and two different tibial ligament insertion locations, that were all located within the normal attachments of the anterior cruciate ligament. Differences were found regarding length changes and tension patterns from a simulated active extension between the central, posterior, and anterior femoral locations. All locations showed larger length change and tension values in extension than in flexion. The anterior femoral ligament insertion location showed length change and tension patterns with increasing values in flexion compared to the other femoral locations. The anterior tibial ligament insertion location showed smaller excursions of both length and tension, than did the central one, but the patterns of the curves were similar. A statistically significant correlation was found between length change and tension patterns throughout a 130-0 degrees range of motion. A statistically significant correlation was also found between the maximum length and tension values. No fixed relationship was found between the magnitude of the length and tension values, when different intervals of the range of motion were studied. RELEVANCE: The intraoperative employment of length change measurements of a test ligament in anterior cruciate ligament reconstruction gives information on where high tension can be expected in the range of motion of the knee, and how this can differ depending on the angle of graft fixation. The information gained can also be used to improve drill channel location. However, no predictions on the magnitude of tension can be made, mainly due to large biological variability.

Journal Article↗
PubMed2006

Sensory nerve injury after uterosacral ligament suspension.

OBJECTIVE: Uterosacral ligament suspension is a technique that is performed commonly to suspend the prolapsed vaginal apex. This case series describes our experience with the clinical evaluation and management of lower extremity sensory nerve symptoms after uterosacral ligament suspension. STUDY DESIGN: Hospital and office medical records from our 2 institutions were reviewed from January 2002 to August 2005, and all women who underwent uterosacral ligament suspension through a vaginal approach were identified. Women with symptoms of buttock and posterior thigh pain during the 6-week postoperative period were identified, and detailed clinical information was abstracted from the charts. RESULTS: From 182 uterosacral ligament suspension procedures, 7 women were identified. The age range was 42 to 70 years. Concurrent procedures included 6 vaginal hysterectomies, 5 anterior repairs, 4 posterior repairs, 2 slings, and 1 bilateral salpingo-oophorectomy. Within 24 hours of the surgical procedure, all the women experienced similar, substantial sharp buttock pain and numbness that radiated down the center of the posterior thigh to the popliteal fossa in 1 or both lower extremities. The ipsilateral uterosacral ligament suture was removed within 2 days of the procedure in 3 women who had immediate subjective reduction in their pain and complete resolution of pain by 6 weeks. The remaining 4 women were treated with gabapentin and narcotics. Three women had resolution of the pain by 12 to 14 weeks after the operation, and the last woman's pain resolved gradually by 6 months. CONCLUSION: Women who undergo uterosacral ligament suspension are at risk of postoperative pain and numbness in a S2-4 distribution. These symptoms appear to be related to the placement of uterosacral ligament sutures and may be relieved either by prompt removal of the ipsilateral uterosacral ligament suture or with prolonged medical therapy.

Adnexa Uteri↗
PubMed1998

Theoretical analysis of ligament and extensor-mechanism function in the ACL-deficient knee.

OBJECTIVE: To study ligament and extensor-mechanism function in the ACL-deficient knee. DESIGN: Mathematical modeling of the muscles, ligaments, and bones at the knee. BACKGROUND: Numerous experiments have documented an increase in anterior tibial translation (ATT) in the ACL-deficient knee, but its effect on the function of the knee-extensor mechanism is not fully understood. The load sharing between the knee ligaments is also unknown since ligament forces are difficult to measure in vivo. METHODS: The geometry of the model bones is adapted from cadaver data. Eleven elastic elements describe the geometric and mechanical properties of the ligaments and joint capsule. The model is actuated by eleven musculotendinous units. Straight, anterior drawer and maximum, isometric extension are simulated by solving the equations for static equilibrium of the model. RESULTS: The moment arm of the extensor mechanism and the torque at the knee are nearly equal in the intact and ACL-deficient model. Knee-ligament forces are lower in the ACL-deficient model than in the intact model. Ligament forces are lower because the shear force applied to the tibia decreases when the model ACL is removed. CONCLUSIONS: Function of the knee-extensor mechanism is not altered by loss of the ACL. The MCL is the primary restraint to anterior drawer in the ACL-deficient knee. The deep fibers of the MCL dominate the load sharing between the ligaments when the ACL is absent.

Journal Article↗
PubMed1998

Determinants of cruciate-ligament loading during rehabilitation exercise.

OBJECTIVES: To predict and explain the pattern of cruciate-ligament loading during squatting exercises; to determine the effect of hamstrings co-contraction on anterior cruciate ligament (ACL) load during squatting; and to determine the effect of the weightbearing force on ACL load during squatting. DESIGN: Mathematical modeling of the human musculoskeletal system. BACKGROUND: Squatting is a commonly prescribed exercise for strengthening the muscles of the thigh following ACL reconstruction. Although the forces induced in the ACL are purported to be low, no experimental data are available to corroborate this claim. The reason is that measurements of knee-ligament forces are difficult to obtain in vivo. METHODS: The human body was modeled as a four-segment, six-degrees of freedom, planar linkage. The hip, ankle and toes were each modeled as a hinge joint. The relative displacements of the femur, tibia and patella were calculated using a three-degrees of freedom, sagittal-plane model of the knee. Eleven elastic were used to describe the geometric and mechanical properties of the knee ligaments. The model was actuated by 22 musculotendinous units. Optimization theory was used to calculate the forces developed in the muscles and the forces transmitted to the knee ligaments during squatting. RESULTS: The model ACL was loaded from full extension to 10 degrees of knee flexion during squatting; the model PCL was loaded at knee-flexion angles greater than 10 degrees. The pattern of cruciate-ligament loading is determined by the shapes of the articulating surfaces of the bones and by the changing orientation of the hamstrings muscles at the knee. Hamstrings co-contraction is the major determinant of ACL loading during squatting exercises; the weightbearing force has a relatively small effect on the force induced in the ACL. CONCLUSION: The calculations support the contention that squatting is a relatively safe exercise for strengthening the muscles of the thigh following reconstruction of the ACL. RELEVANCE: Knowledge of the forces borne by the knee ligaments is important for designing exercise regimens subsequent to ligament injury and repair. The quadriceps and hamstrings muscles may be strengthened without loading a newly reconstructed ACL by performing squats with the knee flexed to 10 degrees and greater.

Journal Article↗
PubMed2006

Degenerative suspensory ligament desmitis as a systemic disorder characterized by proteoglycan accumulation.

BACKGROUND: Degenerative suspensory ligament desmitis (DSLD) is a debilitating disorder thought to be limited to suspensory ligaments of Peruvian Pasos, Peruvian Paso crosses, Arabians, American Saddlebreds, American Quarter Horses, Thoroughbreds, and some European breeds. It frequently leads to persistent, incurable lameness and need to euthanize affected horses. The pathogenesis remains unclear, though the disease appears to run in families. Treatment and prevention are empirical and supportive, and not effective in halting the progression of the disease. Presently, the presumptive diagnosis of DSLD is obtained from patient signalment and history, clinical examination, and ultrasonographic examination of clinically affected horses, and is confirmed at post mortem examination. Presently, there are no reliable methods of diagnosing DSLD in asymptomatic horses. The goal of this study was to characterize and define the disorder in terms of tissue involvement at the macroscopic and microscopic levels. RESULTS: We examined tissues and organs from 28 affected horses (22 Peruvian Pasos, 6 horses of other breeds) and from 8 control horses. Histopathological examination revealed the presence of excessive amounts of proteoglycans in the following tissues removed from DSLD-affected horses: suspensory ligaments, superficial and deep digital flexor tendons, patellar and nuchal ligaments, cardiovascular system, and sclerae. Electron microscopy demonstrated changes in diameters of collagen fibrils in the tendon, and in smooth muscle cells of the media of the aorta compatible with increased cell permeability in DSLD-affected cells. Separation of tendon extracts by gel chromatography revealed the presence of additional proteoglycan(s) in extracts from affected, but not control extracts. CONCLUSION: This study demonstrates for the first time that DSLD, a disease process previously thought to be limited to the suspensory ligaments of the distal limbs of affected horses, is in fact a systemic disorder involving tissues and organs with significant connective tissue component. Abnormal accumulation of proteoglycans between collagen and elastic fibers rather than specific collagen fibril abnormalities is the most prominent histological feature of DSLD. Because of this observation and because of the involvement of many other tendons and ligaments beside the suspensory ligament, and of non-ligamentous tissue we, therefore, propose that equine systemic proteoglycan accumulation or ESPA rather than DSLD is a more appropriate name for this condition.

Journal Article↗
PubMed1996

Ligament Healing: Current Knowledge and Clinical Applications.

The treatment of ligament injuries, particularly knee-ligament injuries, has occupied a substantial portion of the orthopaedic literature for several decades. It remains unclear, however, what orthopaedic surgeons can do to optimize the recovery of patients with ligament problems. In this review, the reasons for this lack of clarity are proposed, and the current state of laboratory knowledge about the response of isolated and multiple ligament injuries to various treatment modalities is reviewed for the ligaments that have been studied thus far (all of which are in the knee). In general, it appears that ligaments heal with scar tissue similar to that involved in skin-wound healing. The early controlled motion of stable (or surgically stabilized) joints appears to improve ligament scar behavior, but no treatment identified to date stimulates true ligament regeneration.

Journal Article↗
PubMed2000

The testicular descent in human. Origin, development and fate of the gubernaculum Hunteri, processus vaginalis peritonei, and gonadal ligaments.

Testicular descent has to be divided into the turn-out of the testis and epididymis from the abdomen proper and an inner abdominal descent of genital organs. Both events are closely related to and depend on the development and reorganisation of ligaments, mainly the gubernaculum Hunteri. These seemingly unambiguous events are controversially described since the first description of the gubernaculum, and results and specifics of other species were intermingled with data from humans, thus giving more confusion than lucidity in this important step of gonadal development. Here, we concentrate on human embryos, chronologically investigated by serial sections, scanning electron microscopy, three-dimensional reconstructions, microdissection and immunohistochemistry. The first question to be answered was whether a real inner descent of gonads occurs. We demonstrated this inner descent by showing the relations of the gonads, mesonephros, cranial mesonephric ligament and the anlage of the diaphragm with the vertebral segments. No explosion-like increase in certain vertebral segments was observed which might simulate a gonadal descent. The inner descent is coupled with the growth of the gonad (ovary or testis), the involution of mesonephros, the descending septum transversum or the anlage of the diaphragm, and the intercalated cranial mesonephric ligament. This ligament always inserts medially at the border between the gonad and mesonephros in close relationship to the abdominal ostium of the müllerian duct, a region where hydatides often occur. In contrast to the testes, the ovaries arrive very early--20-25 mm CRL--at their definitive position of S2/3 (level of linea terminalis pelvis), yet, are transversally oriented. The cranial gonadal ligament does not exhibit notable increase in length during inner descent. It does not contain blood vessels. While regressing in both sexes, it will be replaced by the plica formed by the ovarian vessels, that is the suspensorium ligament of the ovary as known in adults. The second point to be investigated was the origin, development, structure and fate of the gubernaculum Hunteri as well as the processus vaginalis peritonei. Their arrangement and composition is crucial for testicular descent. We discriminated five phases of their development and differentiation. Phase I characterises the early development of the gubernaculum of stage 14 CC (5-7 mm CRL) embryos. It arises as conus inguinalis and connects the abdominal wall lateral to the umbilical artery with the caudal part of the mesonephric fold. It is in this early stage that the localisation of the inner inguinal ring is defined. In phase II, stage 20-23 CC (21-30 mm CRL), three parts of the gubernaculum--abdominal, interstitial and subcutaneous--can be distinguished. The processus vaginalis peritonei appears with its dorsal layer firmly adhering to the ventral side of the gubernaculum. The gubernaculum inserts cranially into the mesenchyme of the genital ducts at their crossing-over. Opposite to it, but at some distance, a ligament connects the caudal pole of the testis with the dorsal mesenchyme of the genital ducts. In female embryos, the analge of the ovarian ligament appears as a U-shaped, double peritoneal fold. Phase II is subdivided in phase IIa (32-55 mm CRL), characterised by an enormous increase in length and volume of the gubernaculum and also an enlargement of the processus vaginalis peritonei. In phase III, sex-specific differences in gonadal position and gubernacular structure can be observed for the first time. Testes increase in volume and come close to the mesenchyme of the genital ducts. The caudal pole of the testis overlaps both ducts. We also subdivide this phase into phase IIIa (about 100 mm CRL) where two very important events occur in male foetuses: 1, the swelling of the gubernaculum, and 2, the gliding of the testis across the genital ducts. This gliding is permitted by both, the regression of the müllerian duct and t

Female↗
PubMed2004

[Ganglion cysts of the knee originating from tendons and ligaments].

PURPOSE: To investigate the clinical features and MR imaging findings of the ganglion cysts arising from the tendons and ligaments of the knee. MATERIALS AND METHODS: One thousand six hundred and twenty knee MR examinations that had been performed in a three-year period were evaluated retrospectively for the presence of ganglion cysts originating from tendons or ligaments. Clinical findings and MRI features of the lesions were noted. RESULTS: Twenty-three patients had a ganglion cyst originating from a tendon or a ganglion, with an incidence of 1.4%. Six lesions were associated with the anterior cruciate ligament, six with the posterior cruciate ligament, six with the medial collateral ligament, two with the lateral collateral ligament, two with the transverse ligament, and one with the patellar tendon. The most common clinical finding was knee pain. There were swelling at the medial side of the knee in two patients, swelling at the lateral side of the knee in one patient and swelling in the popliteal region in one patient. CONCLUSION: MR appearance of ganglion cysts arising from the tendons and ligaments of the knee is characteristic. Meniscal cysts, pigmented villonodular synovitis, and synovial hemangioma should be considered in the differential diagnosis.

Adult↗
PubMed2026

Anatomy and Biomechanics of the Deltoid Ligament Complex in Healthy Ankles: Protocol for a Systematic Review and Meta-Analysis.

INTRODUCTION: Up to one in two individuals who have a history of an ankle injury will develop chronic ankle instability, which subsequently increases the risk of osteoarthritis development. Although lateral ankle ligament injuries are the most common, recent research shows that concomitant injuries to the deltoid (medial collateral) ligament complex may be more prevalent than previously recognised. However, the anatomy and biomechanics of the deltoid ligament complex are reported inconsistently in the literature. This systematic review will summarise current evidence on the anatomy and biomechanics of the deltoid ligament complex in healthy adult ankles. METHODS: Searches will be conducted in Scopus, MEDLINE, Embase, CINAHL and SPORTDiscus. Our search strategy will cover terms associated with 'deltoid ligament', 'anatomy' and 'biomechanics'. We will only include dissection and imaging studies published in English that report any of the listed clinically relevant properties of the deltoid ligament in healthy adult human ankles. Two reviewers will independently perform screening and assess study quality using the anatomical quality assessment (AQUA) tool. One reviewer will extract relevant data, which will be independently verified by co-authors. Primary outcomes include band prevalence, length, width, cross-sectional area, maximum and/or failure load and elastic modulus. If three or more studies report a primary outcome, we will conduct a meta-analysis and report findings as pooled means with 95% confidence intervals. If a meta-analysis is not feasible, outcomes will be summarised as a narrative analysis. Measures will be taken during data synthesis to address anticipated methodological heterogeneity across included studies, and pooled estimates will be interpreted with caution. DISCUSSION: This protocol details a systematic review that aims to summarise the anatomy and biomechanics of the deltoid ligament complex. Our findings will inform computational modelling, clinical management and biomechanics for ankle pathologies, as well as identifying research gaps and directions for future research. TRIAL REGISTRATION: PROSPERO: CRD420251142867.

Humans↗
PubMed1995

Hamstrings and gastrocnemius co-contraction protects the anterior cruciate ligament against failure: an in vivo study in the rat.

An anesthetized rat model was used to study the effects of muscle contraction on the ultimate tensile load and the energy absorption at failure of the anterior cruciate ligament. In both knees, the joint capsule and ligaments, except for the anterior cruciate ligament, were divided, and the menisci were removed with the aid of a stereomicroscope. The cruciate ligament of the right knee was tested in tension until failure by femorotibial distraction during contraction of the hamstrings and calf muscles induced by electrical stimulation of the ischiatic nerve. The cruciate ligament of the left knee, which was loaded to failure with nonstimulated (relaxed) muscles, served as the control. The mean ultimate tensile load during muscle contraction was 86 N compared with 53 N when tested with relaxed muscles (p < 0.001). The energy absorption at failure was 0.41 and 0.19 J during contraction and relaxation, respectively (p < 0.05). This study suggests that previous investigations evaluating the force and energy necessary to rupture the anterior cruciate ligament (with use of a femur-anterior cruciate ligament-tibia complex stripped of all soft tissues and without gastrocnemius-hamstring muscle contractions) are incomplete and probably not representative of the in vivo situation.

Animals↗