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Abstract Background Untreated acute ankle sprains often result in chronic ankle instability (CAI) and can ultimately lead to the development of post-traumatic osteoarthritis (PTOA). At present, a typical animal model of ankle instability in mice is established by transecting the ligaments around the ankle joint. This study aimed to establish a grade I acute ankle sprain animal model by rapid stretching of peri-ankle joint ligaments. Furthermore, we tried to explore the pathophysiological mechanism of ankle osteoarthritis. Methods In all, 18 male C57BL/6 J mice (7 weeks) were randomly divided into three groups: calcaneofibular ligament (CFL) laxity group, deltoid ligament (DL) laxity group, and SHAM group. One week after the surgical procedure, all mice were trained to run in the mouse rotation fatigue machine daily. The mice were tested on the balance beam before surgery and three days, 4 weeks, 8 weeks, and 12 weeks after surgery. Footprint analyses were performed on each mouse before surgery and 12 weeks after surgery. Micro-CT scanning was then performed to evaluate the degeneration of ankle joints and histological staining was performed to analyze and evaluate PTOA caused by ankle joint instability. Results After surgery, the mice in the CFL and DL laxity groups took longer to cross the balance beam and slipped more often than those in the SHAM group (p

Background: Total knee arthroplasty (TKA) in major deformities with ligament insufficiency may require a higher constraint, with bone sacrifice and concerns about long-term survivorship. Mid-level constraint liners have been recently introduced, but few studies described their outcomes. The aim of this study is to evaluate the short to mid-term outcomes of a constrained postero-stabilized (CPS) insert for primary TKA in moderate to severe deformities. Methods: All patients who underwent TKA using a CPS liner in two centers between 2015 and 2017 were included in the study. The indications were: (1) valgus deformity type 2–3 partially correctable; (2) severe varus deformity with varus thrust; (3) post-traumatic deformity with major ligamentous insufficiency and any case of intra-operative ligament insufficiency. Patients were evaluated according to the Knee Society Scoring System (KSS), the Hospital for Special Surgery score (HSS), the Western Ontario and Mc Master University (WOMAC) and the Oxford Knee score (OKS). X-rays were evaluated according to the Knee Society Roentgenographic Evaluation System. Results: Forty-seven TKA were included, with an average age of 66.1 ± 10.3 years and an average follow-up of 68.4 ± 6 months. All patients demonstrated a moderate to severe pre-operative mediolateral instability. All the scores significantly improved (p < 0.0001). In 71.4% of cases, the outcomes were excellent or very good. There were no failures due to aseptic loosening but one failure due to a traumatic ligament rupture. The cumulative survivorship was 97.9% ± 2.1% at 84 months. Conclusions: This mid-range constraint total knee replacement demonstrated promising outcomes and survival at mid-term follow-up. Level of evidence: IV (case series). [ABSTRACT FROM AUTHOR]

The wandering spleen, wandering liver, and wandering kidney are rare diagnoses that can be asymptomatic or are associated with nonspecific symptoms, making the clinical diagnosis elusive. In addition, given the small number of cases, these conditions are not well understood. Major complications of wandering spleen result from torsion of the vascular pedicle with resultant ischemia, physiologic dysfunction, and/or infarction. Wandering liver is commonly associated with bowel obstruction, particularly colonic volvulus, with very rare reports of hepatic ischemia or infarct. Wandering kidneys are not commonly associated with serious complications. In many cases, the wandering spleen, liver or kidney can be found in their anatomic position on static imaging and are only diagnosed during ultrasound or with serial radiographic or cross-sectional imaging with different patient positioning, or with prior studies demonstrating different locations of the involved organ. Treatment approaches for uncomplicated wandering spleen, liver, or kidney include watchful waiting and splenopexy, hepatopexy, or nephropexy, respectively. Complicated wandering spleens are treated with splenectomy. Given the variable clinical presentation of these conditions, imaging plays a pivotal role in diagnosing these rare and often incidentally discovered phenomena. [ABSTRACT FROM AUTHOR]

Hypermobile Ehlers-Danlos syndrome (EDS) is an inherited condition marked by joint hypermobility, instability, chronic pain and fatigue, significantly impacting quality of life and autonomy. Management focuses solely on symptom alleviation. After experiencing a rapid decline in functional abilities, a patient in late adolescence with hypermobile EDS underwent hippotherapy rehabilitation (30 hours). She saw substantial improvements in fatigue, chronic pain and regained walking abilities. Hippotherapy played a crucial role in refining her postural balance, motor skills, proprioception, muscle function and endurance. It also positively affected her cognitive and emotional regulation by stimulating sensory inputs that activate neural pathways, providing relief from pain and fatigue. Notably, the patient transitioned from wheelchair reliance to walking with crutches, and then greatly enhanced both gait quality and speed. These findings demonstrate the relevance of hippotherapy for the rehabilitation of hypermobile EDS, reducing the need for pharmacological interventions and fostering a proactive approach to future challenges., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Case series summary: Cats with non-erosive immune-mediated polyarthritis (IMPA) were identified from seven referral hospitals between 2009 and 2020 for a multicentre retrospective case series. Data were obtained from hospital records and referring veterinarians were contacted for follow-up. Twenty cases were identified: 12 castrated males (60%), one entire male (5%) and seven spayed females (35%). Common clinical signs included lameness (n = 20/20) and pyrexia (n = 10/18). Three cats presented with and two cats developed ligament laxity during treatment. Thirteen cats (65%) were diagnosed with non-associative IMPA and seven (35%) with associative IMPA. Comorbidities identified included chronic enteropathy (n = x/7), feline immunodeficiency virus (n = x/7) feline herpesvirus (n = x/7), bronchopneumonia (n = x/7) and discospondylitis (n = x/7). Sampling of the tarsal joints most frequently identified an increased proportion of neutrophils, consistent with IMPA. Eighteen cats (90%) received immunosuppressants. Eleven cats were started on prednisolone; eight had a poor response resulting in the addition of a second agent, euthanasia or acceptance of the persisting signs. One cat received ciclosporin and required an alternative second agent owing to adverse effects. Five cats were started on prednisolone and ciclosporin; three had a poor response and required an alternative second agent. One cat received prednisolone and chlorambucil and had a good response. Two cats (10%) received meloxicam and had a good response, although the clinical signs recurred when medication was tapered. A good outcome was achieved in 14/20 cats (70%) with IMPA. In the cats with a poor outcome 4/6 were euthanased and 2/6 had chronic lameness. Relevance and novel information: Prognosis for feline IMPA can be good. Multimodal immunosuppression was often required. IMPA should be considered in lame cats, with or without pyrexia, when there is no evidence of trauma or infection. The tarsal joints should be included in the multiple joints chosen for sampling. Ligament laxity can occur in non-erosive feline IMPA. [ABSTRACT FROM AUTHOR]

Introduction: Poor soft tissue balance in total knee arthroplasty (TKA) often results in patient dissatisfaction and reduced joint longevity. Patella-in-place balancing (PIPB) is a novel technique which aims to restore native collateral ligament behavior without collateral ligament release, while restoring post-operative patellar position. This study aimed to assess the effectiveness of this novel technique through a detailed ex vivo biomechanical analysis by comparing post-TKA tibiofemoral kinematics and collateral ligament behavior to the native condition. Materials and methods: Eight fresh-frozen cadaveric legs (89.2 ± 6 years) were tested on a validated dynamic knee simulator, following computed tomography imaging. Specimens were subjected to passive flexion (10–120°), squatting (35–100°), and varus/valgus laxity testing (10 Nm at 0°, 30°, 60°, 90° flexion). An optical motion capture system recorded markers affixed rigidly to the femur, tibia, and patella, while digital extensometers longitudinally affixed to the superficial medial collateral ligament (MCL) and lateral collateral ligament (LCL) collected synchronized strain data. Following native testing, a Stryker Triathlon CR TKA (Stryker, MI, USA) was performed on each specimen and the identical testing protocol was repeated. Statistical analyses were performed using a linear mixed model for functional motor tasks, while Wilcoxon signed-rank test was used for laxity tests (p < 0.05). Results: Postoperative laxity was lower than the native condition at all flexion angles while post-operative ligament strain was lowered only for MCL at 30° (p = 0.017) and 60° (p = 0.011). Postoperative femoral rollback patterns were comparable to the native condition in passive flexion but demonstrated a more pronounced medial pivot during squatting. Conclusions: Balancing a TKA with the PIPB technique resulted in reduced joint laxity, while restoring collateral ligament strains. The technique also seemed to restore kinematics and strains, especially in passive flexion. [ABSTRACT FROM AUTHOR]

Background: The relative impact of soft tissue balance and knee laxity on clinical outcomes after total knee arthroplasty (TKA) is not fully understood. We analyzed associations among knee laxity, kinematics, and patient-reported outcomes.Methods: Knee Society Scores were recorded in 67 patients before and after primary TKA for osteoarthritis with varus deformity (N = 78). Varus and valgus laxity was measured in 78 knees using stress radiographs. Knee kinematics were measured fluoroscopically during stair ascent in 16 knees.Results: On average, varus laxity decreased significantly, and valgus laxity increased significantly after TKA, although the net combined varus-valgus laxity did not change significantly. Postoperatively, the magnitude of valgus laxity correlated significantly with greater patient symptoms and satisfaction scores. Patients with medial pivot kinematics scored higher on patient satisfaction and standard activities.Conclusion: We found that postoperative valgus laxity and medial pivot kinematics were significantly associated with better clinical outcomes. These results emphasize the importance of careful preoperative planning and attention to intraoperative alignment and ligament balancing. [ABSTRACT FROM AUTHOR]

Pregnancy is characterized by hormone changes that could alter musculoskeletal (MSK) properties and temporarily increase soft tissue injury risk. Although the prevalence of MSK injuries in pregnancy has not yet proven itself to be a widespread problem, indirect evidence indicates an uptake in the prevalence of strength training and vigorous-intensity activity during pregnancy, which may result in increased MSK injury incidence. Combining this evidence with the association between sex hormones and MSK injury risk, we recognize the potential importance of this research area and believe the (prospective) examination of connective tissue properties in pregnancy is appropriate. Given the dearth of information on MSK adaptations to pregnancy, we present a variety of morphological, mechanical, and functional tendon data from two consecutive pregnancies in one woman as a means of highlighting this under researched topic. These data may be representative of the general pregnant population, or it may be highly individualized. More research is required for a better understanding of MSK adaptation and injury risk during and after pregnancy. [ABSTRACT FROM AUTHOR]

We present a case of a man in his 40s with a proximal tibiofibular joint dislocation, anterior cruciate ligament (ACL) tear and posterolateral corner (PLC) injury sustained after a cycling accident. Physical examination and MRI confirmed the diagnosis. He was treated with reconstruction of the ACL, PLC and proximal tibiofibular joint. Postoperative treatment included physical therapy to improve knee range of motion and full weight-bearing after 6 weeks. He was able to return to full activities including completing a marathon after 1 year. Identifying proximal tibiofibular joint instability is essential in patients with multiligamentous knee injury as it is often missed. The use of a single tunnel for PLC and proximal tibiofibular joint reconstruction can reduce risk of tunnel convergence., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Mucoid degeneration of the anterior cruciate ligament (ACL) can be treated with arthroscopic debridement, however, instability can ensue. Here, we present a fit and active woman in her 60s with severe mucoid degeneration of the ACL who underwent conservative arthroscopic debridement and treatment with intraligamentous administration of platelet-rich plasma (PRP). After 1 month, the patient demonstrated significant improvements in range of motion and pain symptoms, with nil resultant laxity. The patient was able to return to all recreational sporting activities and professional duties. Quantitative MRI conducted 6 months postoperatively revealed improved fibre orientation and formation of new parallel fibres. Compared with the preoperative scan, the mean grey value demonstrated darker pixel intensity with a smaller standard deviation (SD), potentially indicating a more uniform and less variable formation of ligamentous tissue. Therefore, PRP did not cause harm and was associated with benefit in combination with arthroscopic debridement., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Abstract Biomechanical complications of childbirth, such as obstructed labor, are a major cause of maternal and newborn morbidity and mortality. The impact of birthing position and mobility on pelvic alignment during labor has not been adequately explored. Our objective was to use a previously developed computational model of the female pelvis to determine the effects of maternal positioning and pregnancy on pelvic alignment. We hypothesized that loading conditions during squatting and increased ligament laxity during pregnancy would expand the pelvis. We simulated dynamic joint moments experienced during a squat movement under pregnant and non-pregnant conditions while tracking relevant anatomical landmarks on the innominate bones, sacrum, and coccyx; anteroposterior and transverse diameters, pubic symphysis width and angle, pelvic areas at the inlet, mid-plane, and outlet, were calculated. Pregnant simulation conditions resulted in greater increases in most pelvic measurements – and predominantly at the outlet – than for the non-pregnant simulation. Pelvic outlet diameters in anterior-posterior and transverse directions in the final squat posture increased by 6.1 mm and 11.0 mm, respectively, for the pregnant simulation compared with only 4.1 mm and 2.6 mm for the non-pregnant; these differences were considered to be clinically meaningful. Peak increases in diameter were demonstrated during the dynamic portion of the movement, rather than the final resting position. Outcomes from our computational simulation suggest that maternal joint loading in an upright birthing position, such as squatting, could open the outlet of the birth canal and dynamic activities may generate greater pelvic mobility than the comparable static posture. [ABSTRACT FROM AUTHOR]

Anterior Cruciate Ligament (ACL) injuries are a prevalent concern in athletic population, particularly among female athletes who are disproportionately affected. The increased incidence of ACL injuries in females is attributed to a combination of anatomical, physiological, and biomechanical factors that influence knee stability. This review comprehensively explores these contributing factors, highlighting gender-specific anatomical differences such as wider pelvis, increased quadriceps (Q) angle, and steeper tibial slopes, all of which predispose females to greater knee valgus during dynamic activities. Furthermore, hormonal influences and greater ligament laxity are discussed as physiological contributors to increased ACL injury risk. Biomechanical factors such as reduced knee flexion, increased knee valgus, and altered muscle activation patterns further amplify the risk of ACL tears in female athletes. Despite extensive research, gaps remain in the understanding of how these factors interact and influence injury susceptibility. This article is focussed on the critical points in the current literature, analyzing key risk factors, and identifying future research directions that can inform more effective prevention strategies. A better understanding of these factors will ultimately contribute to reducing the incidence of ACL injuries among female athletes and improving long-term strength and stability of knee joint., Competing Interests: Competing interests: All authors have read the manuscript and declare no conflict of interest. No writing assistance was utilized in the production of this manuscript.

Background Context: Predicting physiological range of motion (ROM) using a finite element (FE) model of the upper cervical spine requires the incorporation of ligament laxity. The effect of ligament laxity can be observed only on a macro level of joint motion and is lost once ligaments have been dissected and preconditioned for experimental testing. As a result, although ligament laxity values are recognized to exist, specific values are not directly available in the literature for use in FE models.Purpose: The purpose of the current study is to propose an optimization process that can be used to determine a set of ligament laxity values for upper cervical spine FE models. Furthermore, an FE model that includes ligament laxity is applied, and the resulting ROM values are compared with experimental data for physiological ROM, as well as experimental data for the increase in ROM when a Type II odontoid fracture is introduced.Design/setting: The upper cervical spine FE model was adapted from a 50th percentile male full-body model developed with the Global Human Body Models Consortium (GHBMC). FE modeling was performed in LS-DYNA and LS-OPT (Livermore Software Technology Group) was used for ligament laxity optimization.Methods: Ordinate-based curve matching was used to minimize the mean squared error (MSE) between computed load-rotation curves and experimental load-rotation curves under flexion, extension, and axial rotation with pure moment loads from 0 to 3.5 Nm. Lateral bending was excluded from the optimization because the upper cervical spine was considered to be primarily responsible for flexion, extension, and axial rotation. Based on recommendations from the literature, four varying inputs representing laxity in select ligaments were optimized to minimize the MSE. Funding was provided by the Natural Sciences and Engineering Research Council of Canada as well as GHMBC. The present study was funded by the Natural Sciences and Engineering Research Council of Canada to support the work of one graduate student. There are no conflicts of interest to be reported.Results: The MSE was reduced to 0.28 in the FE model with optimized ligament laxity compared with an MSE 0f 4.16 in the FE model without laxity. In all load cases, incorporating ligament laxity improved the agreement between the ROM of the FE model and the ROM of the experimental data. The ROM for axial rotation and extension was within one standard deviation of the experimental data. The ROM for flexion and lateral bending was outside one standard deviation of the experimental data, but a compromise was required to use one set of ligament laxity values to achieve a best fit to all load cases. Atlanto-occipital motion was compared as a ratio to overall ROM, and only in extension did the inclusion of ligament laxity not improve the agreement. After a Type II odontoid fracture was incorporated into the model, the increase in ROM was consistent with experimental data from the literature.Conclusions: The optimization approach used in this study provided values for ligament laxities that, when incorporated into the FE model, generally improved the ROM response when compared with experimental data. Successfully modeling a Type II odontoid fracture showcased the robustness of the FE model, which can now be used in future biomechanics studies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Two-thirds of adults worldwide will experience low back pain at some point in their life. In the following case series, we present four patients with sacroiliac (SI) joint instability and severe chronic low back pain, which was refractory to other treatment modalities. OBJECTIVE: We investigated the efficacy of platelet-rich plasma (PRP) injections, a novel orthobiologic therapy, for reducing SI joint pain, improving quality of life, and maintaining a clinical effect. METHODS: Short-form McGill Pain Questionnaire (SFM), Numeric Rating Scale (NRS), and Oswestry Low Back Pain and Disability Index were used for evaluation of treatment at pretreatment, 12-months and 48-months after treatment. RESULTS: At follow-up 12-months post-treatment, pooled data from all patients reported a marked improvement in joint stability, a statistically significant reduction in pain, and improvement in quality of life. The clinical benefits of PRP were still significant at 4-years post-treatment. CONCLUSIONS: Platelet-rich plasma therapy exhibits clinical usefulness in both pain reduction and for functional improvement in patients with chronic SI joint pain. The improvement in joint stability and low back pain was maintained at 1- and 4-years post-treatment. [ABSTRACT FROM AUTHOR]

Alignment of normal, arthritic and replaced human knees is a much debated subject as is the collateral ligamentous laxity. Traditional quantitative values have been challenged. Methods used to measure these are also not without flaws. Authors review the recent literature and a novel method of measurement of these values has been included. This method includes use of computer navigation technique in clinic setting for assessment of the normal or affected knee before the surgery. Computer navigation has been known for achievement of alignment accuracy during knee surgery. Now its use in clinic setting has added to the inventory of measurement methods. Authors dispel the common myth of straight mechanical axis in normal knees and also look at quantification of amount of collateral knee laxity. Based on the scientific studies it has been shown that the mean alignment is in varus in normal knees. It changes from lying non weight bearing position to standing weight bearing position in both coronal and the sagittal planes. It also varies with gender and race. The collateral laxity is also different for males and females. Further studies are needed to define the ideal alignment and collateral laxity which the surgeon should aim for individual knees.

Contemporary finite element (FE) neck models are developed in a neutral posture; however, evaluation of injury risk for out-of-position impacts requires neck model repositioning to non-neutral postures, with much of the motion occurring in the upper cervical spine (UCS). Current neck models demonstrate a limitation in predicting the intervertebral motions within the UCS within the range of motion, while recent studies have highlighted the importance of including the tissue strains resulting from repositioning FE neck models to predict injury risk. In the current study, the ligamentous cervical spine from a contemporary neck model (GHBMC M50 v4.5) was evaluated in flexion, extension, and axial rotation by applying moments from 0 to 1.5 N·m in 0.5 N·m increments, as reported in experimental studies and corresponding to the physiologic loading of the UCS. Enhancements to the UCS model were identified, including the C0-C1 joint-space and alar ligament orientation. Following geometric enhancements, an analysis was undertaken to determine the UCS ligament laxities, using a sensitivity study followed by an optimization study. The ligament laxities were optimized to UCS-level experimental data from the literature. The mean percent difference between UCS model response and experimental data improved from 55% to 23% with enhancements. The enhanced UCS model was integrated with a ligamentous cervical spine (LS) model and assessed with independent experimental data. The mean percent difference between the LS model and the experimental data improved from 46% to 35% with the integration of the enhanced UCS model. [ABSTRACT FROM AUTHOR]

Post-traumatic arthritis can result in significant pain and difficulty in managing daily life activities. Multiple factors are weighed in selecting the proper surgical intervention, with patient age and level of activity being most important. Isolated osteoarthritis is a well-known indication for unicompartmental knee arthroplasty, where a better range of motion, preservation of natural knee kinematics and less invasive resection of knee joint bone are used. Moreover, the high improvement rate and long-term results after anterior cruciate ligament (ACL) reconstruction and restoration of knee stability can make the combined procedure favourable, particularly for young active patients.We report on an active man in his 30s presenting with isolated medial compartment advanced arthritis after sustaining distal femur intra-articular fracture. He was initially treated with partial unicompartmental knee replacement combined with ACL reconstruction, delivering a good short-term follow-up outcome.Though this case involves just a single patient, the positive outcome suggests that combined partial unicompartmental knee replacement with an ACL reconstruction should be considered for young and active patients diagnosed with isolated advanced medial compartment osteoarthritis., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To evaluate the clinical outcome of this modified physeal-sparing technique for MPFL reconstruction in skeletally immature patients with ligament laxity. Patients and methods: This study was conducted on 16 patients (11 females and 5 males) with an average age of 11.5 years (8-15). They all had recurrent patellar dislocation with generalized ligament laxity (mean Beighton's score of 7) and no patellar tilt on X-ray. We modified the Frank Noyes' non-anatomic technique for MPFL reconstruction to become anatomic without hardware fixation for the graft. Results: The mean follow-up period was 29.25 months (SD 4.3) ranged from 24 to 34 months. Preoperative Kujala score had ranged from 49 to 61 points (mean of 56, SD 4.72), improved to be ranged from 90 to 99 points (mean 94, SD 2.73), which is considered highly significant ( p value < 0.005). Till the latest follow-up, there were no definite re-dislocation episodes in any of our patients. Conclusion: The described technique allows reconstruction of the MPFL in skeletally immature patients with ligament laxity avoiding any potential risks of growth disturbances or chondral damage as compared to other techniques. The modification of two-point femoral fixation allows both a more anatomic and more secure form of reconstruction and is cost-effective without the need for hardware. [ABSTRACT FROM AUTHOR]

Hypermobility of the first ray is suggested to contribute to hallux valgus. The investigation of first ray hypermobility focused on the mobility and range of motion that based on manual examination. The load transfer mechanism of the first ray is important to understand the development and pathomechanism of hallux valgus. In this study, we investigated the immediate effect of the joint hypermobility on the metatarsocuneiform and metatarsophalangeal joint loading through a reduction of the stiffness of the foot ligaments. A three-dimensional foot model was constructed from a female aged 28 via MRI. All foot and ankle bones, including two sesamoids and the encapsulated bulk tissue were modeled as 3D solid parts, linking with ligaments of shell elements and muscles connectors. The stance phase of walking was simulated by the boundary and loading conditions obtained from gait analysis of the same subject. Compared with the normal foot, the hypermobile foot had higher resultant metatarsocuneiform and metatarsophalangeal joint forces. The increases accounted for 18.6% and 3.9% body weight. There was also an abrupt change of metatarsocuneiform joint force in the medial–lateral direction. The predicted results represented possible risk of joint problems and metatarsus primus varus. [ABSTRACT FROM AUTHOR]

These authors describe an orthosis they have successfully used in their clinic to treat patients with distal radioulnar joint instability. In addition to describing how they fabricate the orthosis, these authors also describe how they determine if the patient needs volar or dorsal support, and how they then incorporate this support into the orthosis – Victoria Priganc, PhD, OTR, CHT, CLT, Practice Forum Editor. [ABSTRACT FROM AUTHOR]

There continues to be some dissatisfaction with the function of total knee arthroplasties (TKA). 'Mid-range instability' has been linked to multi-radius femoral components allowing transient ligament slackness and instability during knee flexion. Single-radius designs have been introduced to avoid this. We compared the kinematics and stability of eight natural knees versus multi-radius and single-radius TKAs in vitro. The loading conditions imposed across the range of active knee extension were anterior-posterior drawer forces, internal-external rotation torques, and varus-valgus moments. Significant differences were not found between the biomechanical behavior of the two TKAs. Both were significantly different from the natural knee in allowing greater anterior drawer laxity near extension, probably caused by excision of the anterior cruciate ligament, but no difference occurred beyond 30° flexion. No differences were found for any of the other degrees-of-freedom of movement. A geometric analysis suggested that the multi-radius design may tense the MCL more than the single-radius in mid-flexion, contrary to expectation. These kinematic and stability tests did not find mid-range instability of the knees, and so they could not demonstrate enhanced mid-range stability of the single-radius TKA over the older multi-radius implant. This suggests that mid-range instability may relate to unrecognized ligament laxity during surgery, rather than being inherent to a specific feature of implant design. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:53-58, 2012 [ABSTRACT FROM AUTHOR]

People suffering from Ehlers-Danlos syndrome (EDS) hypermobility type present a severe ligament laxity that results in difficulties in muscle force transmission. The same condition is present in people suffering from Down syndrome (DS) even if their clumsy movements are due to cerebral and cognitive impairments. The aim of this study was to quantify the gait patterns of subjects with EDS and with DS using Gait Analysis (GA). We quantified the gait strategy in 12 EDS individuals and in 16 participants with DS. Both pathological groups were compared to 20 age-matched healthy controls in terms of kinematics and kinetics. Results showed that DS individuals are characterized by a more compromised gait pattern than EDS participants, even if both groups are characterized by joint hypermobility. All the patients showed significant decreased of ankle stiffness probably due to congenital hypotonia and ligament laxity, while different values of hip stiffness. These findings help to elucidate the complex biomechanical changes due to joint hypermobility and may have a major role in the multidimensional evaluation and tailored management of these patients. [Copyright &y& Elsevier]

Ehlers-Danlos syndrome is a heterogeneous connective tissue condition characterized by varying degrees of skin hyperextensibility, joint hypermobility, and vascular fragility. Joint dislocations, musculoskeletal pain, atrophic scars, easy bleeding, vessel/viscera rupture, severe scoliosis, and obstetric complications may occur. These manifestations are secondary to abnormal collagen, with specific molecular defects in types I, III, and V collagen; they may also be related to tenascin-X, which has been identified in some patients. Ehlers-Danlos syndrome has been classified into 6 types, with variable degrees of joint instability, skin hyperextensibility, wound healing difficulty, and vascular fragility. Diagnosis begins with recognition of the signs and symptoms of global hypermobility and referring appropriate patients for genetic consultation. It is important to accurately identify patients with Ehlers-Danlos syndrome to initiate appropriate musculoskeletal treatment, optimize anesthetic and postoperative management, perform appropriate vascular screening, and help families address their concerns with other families and advocacy groups. [ABSTRACT FROM AUTHOR]

Abstract: Floating knee injury is described as the simultaneous ipsilateral disruption of skeletal integrity above and below the knee. It is usually associated with high-energy impact and often a part of polytrauma. Management of associated life-threatening injuries should take precedence over the orthopedic injury. The soft tissue trauma to the limb is significant and it is prudent to be wary. Despite a high complication rate, early skeletal stabilization and timely postoperative rehabilitation offer the best chance of a favorable outcome. [Copyright &y& Elsevier]

The aim of this paper is to describe the clinical features and radiological appearance of a rare and complex lower leg and foot deformity in hyperlax children. Four children were included in the study; of these, two had bilateral feet involvement. All deformities were present since birth, comprising a pentad of conditions: (1) pathologic external tibia and fibula torsion, (2) ball and socket ankle joint with medial subluxation and talus medial subluxation, (3) excessive hindfoot valgus, (4) peroneal and Achilles tendon displacement anterior to the lateral malleolus and (5) generalized ligament laxity. All children had failed cast manipulation. Only two had undergone a minimal soft tissue procedure, but there had been no improvement. All patients were ambulatory and pain free at the mean age of 6.5 years. Conservative or minimal soft tissue procedures are not effective in restoring the anatomy of such feet. [ABSTRACT FROM AUTHOR]

In a 51-year-old woman with a history of fractures and dislocations after low intensity trauma in childhood, intensive blue sclera, short stature, and hearing loss, the diagnosis of osteogenesis imperfecta (OI) was suspected. She was referred to our clinic with hand deformities and left knee pain and stiffness. She had difficulty in walking and reported a history of immobilization for 6 months because of knee pain. She had bilateral flexion contracture of the elbows which occurred following dislocations of the elbows in childhood. She had Z deformity of the first phalanges, reducible swan-neck deformity of the third finger of the left and the second finger of the right hand, flexion contracture of the proximal interphalangeal joint of the fifth finger of the left hand, and syndactyly of the third and fourth fingers of the right hand. Flexion contractures of both knees were observed. Pes planus and short toes were the deformities of the feet. Acute phase reactants of the patient were normal. She had no history of arthritis or morning stiffness. Bone mineral density evaluated by dual-energy X-ray absorptiometry (DEXA) showed severe osteoporosis of the femur and lumbar vertebrae. She had radiographic evidence of healed fractures of the left fibula, the third metacarpal, and the fourth and fifth middle phalanges of the right hand. OI, affecting the type I collagen tissue of the sclera, skin, ligaments, and skeleton, presenting with ligament laxity resulting in subluxations and hand deformities may be misdiagnosed as hand deformities of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

A common finding in progressive osteoarthritis of the carpometacarpal joint of the thumb is ligamentous laxity. In patients with Ehlers-Danlos syndrome, which is a disorder characterized by generalized ligamentous laxity, splinting and arthrodesis have been recommended because of the random results achieved by other reconstructive procedures. We report a patient with thumb carpometacarpal joint osteoarthritis secondary to Ehlers-Danlos syndrome who was treated with bilateral arthroscopic tendon interposition arthroplasty. [Copyright &y& Elsevier]

Abstract: Background. Evaluation of anterior ankle joint laxity remains an intriguing clinical problem. Manual examination is of subjective nature. The aim of the present in-vitro and in-vivo study was to develop a tester for quantitative measurement of anterior ankle joint laxity. Methods. The tester was evaluated on 7 cadaver specimens and on 24 individuals, 14 with prior ligament injury and 10 without. Subsequently, a post hoc analysis was performed on 6 individuals without ligament injury. Findings. In the cadaver tests, mean increase in anterior displacement was 2.0mm (SD 1.6) with cut anterior talofibular ligament, 2.7mm (SD 2.7) with cut anterior talofibular and calcaneofibular ligaments and 3.3mm (SD 3.3) with cut anterior talofibular, calcaneofibular and posterior talofibular ligaments. In the normal subjects, mean displacement was 23mm (SD 6.6) for left and 25mm (SD 7.5) for right ankles. In the group of subjects with prior ankle ligament injuries but no instability symptoms, there was no detectable laxity difference between injured and non-injured. The intra-observer reliability for the tester was 0.94. Post-hoc analysis showed a device-related systematic error of<1mm. Interpretation. The displacement values present the motion between the anterior aspect of the distal tibia and the posterior aspect of the heel, not solely motion in the ankle joint but in the entire ankle joint complex. The test principle has the potential to provide an objective value for anterior displacement values of the ankle joint. The test apparatus in its present form is not suitable for use in clinical practice. [Copyright &y& Elsevier]