What effect does preoperative flexion contracture have on the component angles in unicompartmental knee arthroplasty?

PURPOSE: The indication for unicompartmental knee arthroplasty (UKA) has been extended to cases with some degree of preoperative knee flexion contracture recently. The purpose of this study was to clarify the effect of flexion contracture on component angles. MATERIALS AND METHODS: Thirty-five fixed-bearing UKAs using the spacer block technique with preoperative flexion contracture (Group FC) and 35 UKAs using the same technique without preoperative flexion contracture (Group NC) were included. Using radiographs, the coronal femoral component angle, coronal tibial component angle, sagittal femoral component angle, and sagittal tibial component angle were determined. Also, extension and flexion angles of the knee as well as coronal Hip-Knee-Ankle (HKA) angles in long-leg standing radiographs were measured. The data about the thickness of the selected insert were also collected. The above results were compared between the two groups. RESULTS: The femoral component tended to be placed in a more varus and flexed position in Group FC, while no significant difference was found about the tibial component angles. While there was no significant difference in pre- and postoperative knee flexion angles between the two groups, flexion contracture remained postoperatively in Group FC. Preoperative HKA angle was greater in Group FC while the difference was no longer significant postoperatively. Regarding the thickness of the selected insert, thicker inserts tended to be used in Group FC. CONCLUSIONS: In fixed-bearing UKA with the spacer block technique, the femoral component tended to be placed in a flexed and varus position in the knees with preoperative flexion contracture.

Acquired Hallux Varus Deformity Correction: Pivotless Distraction Technique.

Acquired hallux varus deformity secondary to postburn contracture is a rare condition. It causes cosmetic disfigurement, pain, and inability to wear a shoe. Soft-tissue procedures and tendon transfers have been described for correction; however, these may require multiple operations and the outcome may be poor. We report a 6-year-old neglected case of hallux varus deformity secondary to burn contracture successfully managed by contracture release with pivotless distraction technique using a biplanar distractor and skin grafting with Z-plasty in the same procedure. The deformity was corrected to a lesser extent and with good functional outcomes. The scar was excised and Z-plasty was performed. The medial joint capsule was released. We used gradual differential distraction with monitoring on sequential radiographs. Pain-free flexion of 45° and extension of 40° were achieved and the patient was able to wear shoes after 4 weeks postoperatively. Hallux varus is a multidimensional deformity. A severe and rigid deformity might not respond well to tendon transfers in a single stage. Our described technique can be used to correct rigid hallux varus deformity with preservation of joint function.

Dynamic Analysis of the Coracohumeral Ligament Using Ultra-Sonography in Shoulder Contracture.

The coracohumeral ligament (CHL) is related to the range of motion of the shoulder joint. The evaluation of the CHL using ultrasonography (US) has been reported on the elastic modulus and thickness of the CHL, but no dynamic evaluation method has been established. We aimed to quantify the movement of the CHL by applying Particle Image Velocimetry (PIV), a technique used in the field of fluid engineering, to cases of shoulder contracture using the US. The subjects were eight patients, with 16 shoulders. The coracoid process was identified from the body surface, and a long-axis US image of the CHL parallel to the subscapularis tendon was drawn. The shoulder joint was moved from 0 degrees of internal/external rotation to 60 degrees of internal rotation at a rhythm of one reciprocation every 2 s. The velocity of the CHL movement was quantified by the PIV method. The mean magnitude velocity of CHL was significantly faster on the healthy side. The maximum magnitude velocity was significantly faster on the healthy side. The results suggest that the PIV method is helpful as a dynamic evaluation method, and in patients with shoulder contracture, the CHL velocity was significantly decreased.

Sagittal alignment in patients with flexion contracture of the hip before and after total hip arthroplasty.

INTRODUCTION: In hip osteoarthritis, hip flexion contracture can severely alter the patient's alignment, and, therefore, affect the patient's quality of life (QOL). Hip contracture is not well-studied, partly because of the difficulties of its diagnosis. The aim of this study was to propose a quantitative definition of hip flexion contracture, and to analyse sagittal alignment in these patients compared to non-contracture ones, before and 12 months after total hip arthroplasty (THA). MATERIALS AND METHODS: Consecutive patients with hip arthrosis and an indication for THA were included (N = 123). Sagittal full-body radiographs were acquired in free standing position and in extension. QOL questionnaires were administered before and after surgery. Spinopelvic parameters were measured, including the pelvic-femur angle (PFA). Patients with low pelvic incidence (< 45°) were included in the hip contracture group if PFA > 5°, or PFA > -5° when pelvic incidence ≥ 45°. RESULTS: 29% of patients were in the hip flexion contracture group, and they showed lower pelvic tilt than the no-contracture group (p < 0.001), larger lumbar lordosis (LL) and smaller PI-LL (p < 0.001), as well as a forward position of the head. 16% of patients still had hip contracture 12-months postop. Contracture patients showed higher QOL scores after surgery. CONCLUSIONS: The proposed method to diagnose hip contracture group allowed to define a group of patients who showed a specific pattern of sagittal spinopelvic alignment. These patients improved their alignment and quality of life postoperatively, but their hip mobility was not always restored. Diagnosing these patients is a first step toward the development of more specific surgical approaches, aiming to improve their surgical outcome.

Recognizable Pattern of Arthrogryposis and Congenital Myopathy Caused by the Recurrent TTN Metatranscript-only c.39974-11T > G Splice Variant.

INTRODUCTION: Arthrogryposis is characterized by the presence of multiple contractures at birth and can be caused by pathogenic variants in TTN (Titin). Exons and variants that are not expressed in one of the three major isoforms of titin are referred to as "metatranscript-only" and have been considered to be only expressed during fetal development. Recently, the metatranscript-only variant (c.39974-11T > G) in TTN with a second truncating TTN variant has been linked to arthrogryposis multiplex congenita and myopathy. METHODS: Via exome sequencing we identified the TTN c.39974-11T > G splice variant in trans with one of three truncating variants (p.Arg8922*, p.Lys32998Asnfs*63, p.Tyr10345*) in five individuals from three families. Clinical presentation and muscle ultrasound as well as MRI images were analyzed. RESULTS: All five patients presented with generalized muscular hypotonia, reduced muscle bulk, and congenital contractures most prominently affecting the upper limbs and distal joints. Muscular hypotonia persisted and contractures improved over time. One individual, the recipient twin in the setting of twin-to-twin transfusion syndrome, died from severe cardiac hypertrophy 1 day after birth. Ultrasound and MRI imaging studies revealed a recognizable pattern of muscle involvement with striking fibrofatty involvement of the hamstrings and calves, and relative sparing of the femoral adductors and anterior segment of the thighs. CONCLUSION: The recurrent TTN c.39974-11T > G variant consistently causes congenital arthrogryposis and persisting myopathy providing evidence that the metatranscript-only 213 to 217 exons impact muscle elasticity during early development and beyond. There is a recognizable pattern of muscle involvement, which is distinct from other myopathies and provides valuable clues for diagnostic work-up.

Development of Contractures in DMD in Relation to MRI-Determined Muscle Quality and Ambulatory Function.

BACKGROUND: Joint contractures are common in boys and men with Duchenne muscular dystrophy (DMD), and management of contractures is an important part of care. The optimal methods to prevent and treat contractures are controversial, and the natural history of contracture development is understudied in glucocorticoid treated individuals at joints beyond the ankle. OBJECTIVE: To describe the development of contractures over time in a large cohort of individuals with DMD in relation to ambulatory ability, functional performance, and muscle quality measured using magnetic resonance imaging (MRI) and spectroscopy (MRS). METHODS: In this longitudinal study, range of motion (ROM) was measured annually at the hip, knee, and ankle, and at the elbow, forearm, and wrist at a subset of visits. Ambulatory function (10 meter walk/run and 6 minute walk test) and MR-determined muscle quality (transverse relaxation time (T2) and fat fraction) were measured at each visit. RESULTS: In 178 boys with DMD, contracture prevalence and severity increased with age. Among ambulatory participants, more severe contractures (defined as greater loss of ROM) were significantly associated with worse ambulatory function, and across all participants, more severe contractures significantly associated with higher MRI T2 or MRS FF (ρ: 0.40-0.61 in the lower extremity; 0.20-0.47 in the upper extremity). Agonist/antagonist differences in MRI T2 were not strong predictors of ROM. CONCLUSIONS: Contracture severity increases with disease progression (increasing age and muscle involvement and decreasing functional ability), but is only moderately predicted by muscle fatty infiltration and MRI T2, suggesting that other changes in the muscle, tendon, or joint contribute meaningfully to contracture formation in DMD.

Congenital Contracture of the Ulnar Digits and Its Differentiation From Ischemic Contracture.

PURPOSE: To describe the clinical features, radiologic findings, differential diagnosis, and surgical treatment of a congenital flexion deformity of the middle, ring, and little fingers. The cause of the condition is the aberrant origin of the flexor digitorum profundus, leading to a congenital contracture of the ulnar digits. METHODS: We reviewed 8 patients with congenital contracture of the ulnar digits. The mean age at the time of surgery was 14 years. An examination revealed a flexion contracture of the middle, ring, and small fingers. Plain radiographs, 3-dimensional computed tomography, magnetic resonance imaging, and ultrasound were used to characterize bony and soft tissue pathology. Surgical treatments included resection of the aberrant origin and a muscle-sliding procedure. RESULTS: Bony prominence on the proximal ulna was seen in the plain radiographs and/or 3-dimensional computed tomography. A cord that extended from this bony prominence to the tendons of flexor digitorum profundus was revealed in the magnetic resonance imaging. The bony prominence and the cord were also seen using ultrasound. The median time of patient follow-up was 1.7 years. A simple resection of the tendinous origin only resulted in a release in 2 patients who were 4 years old. Older patients required a further muscle-sliding procedure. The average grip strength ratio on the contralateral side was 82%. CONCLUSIONS: Congenital contracture of the ulnar digits is a new congenital flexion deformity involving the middle, ring, and small fingers. Bony prominence on the proximal ulna is the key finding for establishing its diagnosis and distinguishing it from an ischemic contracture. We recommend treating this surgically at 12 years of age or older after the phase of rapid growth of the extremities. We recommend the resection of the aberrant origin, combined with a muscle-sliding procedure, as the treatment of choice, even for young patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic V.

Flexion contracture is associated with knee joint degeneration on magnetic resonance imaging: data from the Osteoarthritis Initiative.

OBJECTIVES: Knee osteoarthritis (OA) is often accompanied by a flexion contracture (FC), resulting in worse clinical outcomes. Our objective was to determine associations between knee FC and specific regional and/or structural alterations on magnetic resonance imaging (MRI) using the Osteoarthritis Initiative (OAI). METHODS: 600 knees from the Foundation for the National Institutes of Health sub-study of the OAI were included. Knee extension was measured with a goniometer and FC was defined as inability to extend the knee to 0°. Structural alterations within the MRI Osteoarthritis Knee Score (MOAKS)-assessed regions that could potentially obstruct knee extension were primarily analysed. Multivariable linear regression models evaluated the effect size of MRI outcomes on knee extension. RESULTS: One-third (33.4%) of all participants had knee FC: 155 mild (1-5°, 26.0%), 44 moderate-severe (≥6°, 7.4%). Mean knee alignment was 0.3±3.7° valgus. Cartilage morphology and bone marrow lesion (BML) scores on the femoral side of the lateral patellofemoral joint were associated with lost knee extension (ß=0.709, p<0.001, and ß=0.666, p<0.001, respectively) as were higher osteophyte scores in multiple regions, worse meniscal score in the medial meniscal body (ß=0.164, p<0.040) and posterior horn (ß=0.400, p<0.001), and a worse effusion score (ß=0.711, p<0.001). CONCLUSIONS: Knee flexion contractures were associated with non-specific, widespread MRI degenerative changes including cartilage loss and BMLs in the lateral patellofemoral joint, osteophytes, meniscal alterations and whole-joint effusion. Loss of knee extension in OA is likely a structurally-multifactorial outcome.

Care Pathway for Foetal Joint Contractures, Foetal Akinesia Deformation Sequence, and Arthrogryposis Multiplex Congenita.

INTRODUCTION: The majority of arthrogryposis multiplex congenita (AMC) and lethal forms of AMC such as foetal akinesia deformation sequence (FADS) cases are missed prenatally. We have demonstrated the additional value of foetal motor assessment and evaluation in a multidisciplinary team for the period 2007-2016. An applied care pathway was developed for foetuses presenting with joint contracture(s) in one anatomic region (e.g., talipes equinovarus [TEV]), more than one body part with non-progressive contractures and motility (AMC) and with deterioration over time (FADS). METHODS: The multidisciplinary team of Amsterdam University Medical Centre Expertise Centre FADS and AMC developed the care pathway. Additional tools are provided including a motor assessment by ultrasound examination and a post-mortem assessment form. RESULTS: An eight-step care pathway is presented with a proposed timing for prenatal sonographic examination, genetic examinations, multidisciplinary meetings, prenatal and postnatal counselling of the parents by a specialist also treating after birth, and the follow-up of prenatal and postnatal findings with counselling for future pregnancies. DISCUSSION/CONCLUSION: The scheduled serial structural and motor sonograpahic assessment together with follow-up examinations and genetic analysis should be tailored per prenatal centre per available resources. The multidisciplinary care pathway may pave the way to increase the detection rate and diagnosis of isolated contracture(s), TEV with underlying genetic causes, and the rare phenotypes AMC/FADS and prompt treatment after birth within expertise teams.

Expanding the phenotypic spectrum of Mendelian connective tissue disorders to include prominent kidney phenotypes.

Heritable connective tissue disorders are a group of diseases, each rare, characterized by various combinations of skin, joint, musculoskeletal, organ, and vascular involvement. Although kidney abnormalities have been reported in some connective tissue disorders, they are rarely a presenting feature. Here we present three patients with prominent kidney phenotypes who were found by whole exome sequencing to have variants in established connective tissue genes associated with Loeys-Dietz syndrome and congenital contractural arachnodactyly. These cases highlight the importance of considering connective tissue disease in children presenting with structural kidney disease and also serves to expand the phenotype of Loeys-Dietz syndrome and possibly congenital contractural arachnodactyly to include cystic kidney disease and cystic kidney dysplasia, respectively.

Multivariate analysis of the relationship between gluteal muscle contracture and coxa valga.

BACKGROUND: Gluteal muscle contracture (GMC) is a disease characterized by the limited function of the hip joint, knee pain, and abnormal gait. There is a lack of research on the effect of GMC on the hip joint structure to date. This study aims to analyze the association between GMC and the deformity of the hip and pelvis. METHODS: Standing anteroposterior pelvic radiographs of 214 patients (152 with gluteal muscle contracture and 62 without gluteal muscle contracture) were retrospectively collected. Neck-shaft angle, lateral center edge angle, Tönnis angle, femoral head coverage index, acetabular depth, Sacro-femoral-pubic angle, and obturator foramen ratio were respectively measured and included in the following statistical analysis. The collected data were analyzed using logistical regression and multiple linear regression to explore the factors influencing coxa valga and SFP angle. RESULTS: GMC was identified as a common factor significantly associated with coxa valga and increased SFP angle. There is a difference of risk factors in logistic regression for coxa valga between the left and right sides. CONCLUSION: GMC is a significant risk factor for coxa valga and increased SFP angle. Given that GMC can cause coxa valga and likely alter the pelvis's position, GMC should be paid attention to and treated early.

Brief report: Passive mechanical properties of gastrocnemius in multiple sclerosis and ankle contracture.

BACKGROUND: Ankle contracture is common in people with multiple sclerosis (MS) but the mechanisms of contracture are not clear. This study aimed to identify the mechanisms of contracture in MS by comparing passive muscle length and stiffness at known tension, separated into contributions by muscle fascicles and tendons, between people with MS who had contracture and healthy people. METHODS: Passive length-tension curves of the gastrocnemius muscle-tendon unit were derived from passive ankle torque and angle using a published biomechanical method. Ultrasound images of medial gastrocnemius muscle fascicles were used to partition length-tension curves into fascicle and tendon components. Lengths and stiffness of the muscle-tendon unit, muscle fascicles and tendons were compared between groups with linear regression. FINDINGS: Data were obtained from 15 participants with MS who had contracture [age 53 (12) years, mean (SD)] and 25 healthy participants [48 (20) years]. Participants with MS had clinically significant ankle contracture, and had shorter fascicles at slack length (between-groups mean difference -0.8 cm, 95% CI -1.2 to -0.4 cm, p < 0.001) and at 100 N (-0.7 cm, 95% CI -1.3 to -0.1 cm, p = 0.02) compared to healthy participants. There were no differences between groups in all other outcomes. INTERPRETATION: Tension-referenced comparisons of passive muscle length and stiffness show that people with MS who had contracture had shorter fascicles at low and high tension compared to healthy people, but there were no changes to the muscle-tendon unit or tendon. Further studies are needed to identify the causes and mechanisms of contracture in neurological conditions.

3D images of the silicone implants in capsular contracture after breast augmentation using magnetic resonance imaging with SPACE sequence.

BACKGROUND: Capsular contracture is a common complication after breast augmentation. However, no objective methods are available to assess capsular contracture at present. The goal of the present study was to evaluate the correlation between capsular contracture and 3D images of the silicone implants by using magnetic resonance imaging (MRI) with sampling perfection with application optimized contrast using different flip angle evolutions (SPACE) sequence. METHODS: Twenty-one patients (42 breasts) underwent breast augmentation, had postoperative MRI examinations with SPACE sequence, and the evaluation of the Baker grade by two trained plastic surgeons. Capsular thickness was measured on the T2-weighted images. The software ITK-SNAP was used to reconstruct 3D images of the implants. The fold characteristics such as number, depth, direction, and distribution were compared with the Baker grade. RESULTS: Of the 42 breasts, 14, 8, 12, and 8 breasts were classified as Baker grade I, II, III, and IV, respectively. The MRI images of breasts with Baker grade III or IV revealed a thicker capsule (mean of 2.29 mm) as compared to the capsule with the lower Baker grades (mean of 1.58 mm). The 3D images of implants showed no difference in the number of folds between the groups with different Baker grades. The fold direction and fold distribution differed between grade I to II and grade III to IV. CONCLUSION: The 3D image of an implant with pathological folds is a potential and feasible diagnostic indication of capsular contracture. LEVEL OF EVIDENCE: IV.

Confirming the involvement of PIEZO2 in the etiology of Marden-Walker syndrome.

Pathogenic heterozygous variants in PIEZO2 typically cause distal arthrogryposis type 5 (DA5) and the closely related Gordon syndrome (GS). Only one case of PIEZO2-related Marden-Walker syndrome (MWS) has been reported to date. We report the phenotypic features of a Saudi female patient with features consistent with MWS in whom we identified a novel de novo likely pathogenic variant in PIEZO2. Our case lends support to the link between PIEZO2 and MWS.

Growth modulation for fixed flexion contracture of the knee: a comparison of two techniques.

Growth modulation has become a mainstream treatment for frontal plane angular lower extremity deformities in children. Few articles address the effect of growth modulation on sagittal deformity. Our aim is to compare two anterior distal femoral growth modulation techniques for fixed knee flexion contracture. Electronic medical records were reviewed for patients who underwent anterior femoral growth modulation for fixed flexion contracture. Patients were excluded if adequate preoperative/postoperative radiographs were unavailable. A cohort was subdivided based on surgical technique: screws alone versus dual tension-band plates. Complications were recorded; radiographs were evaluated preoperatively and at hardware removal. Posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA), and anterior cortical line (ACL) angle were evaluated. Of 35 patients identified, 20 patients (29 knees) were included. Thirteen knees were treated with dual anterior tension-band plates; 16 knees had transphyseal screws. Sagittal alignment improved in both groups. Statistically significant PDFA changes were observed in the tension-band plate group (P = 0.0095); a trend was noted toward improvement in ACL angle (P = 0.08). PPTA did not change. No changes reached significance in the transphyseal screw group (PDFA: P = 0.181, ACL: P = 0.64). Tension-band plate migration was noted in one (7.7%) of 13 knees, and transphyseal screw migration in nine (56.3%) of 16 knees (P < 0.01). Anterior distal femoral growth modulation improves sagittal alignment without significant remodeling at the proximal tibia. Hardware migration occurred more often with transphyseal screws (P < 0.01). We recommend dual anterior tension-band plating over placement of paired screws for sagittal growth modulation to treat knee flexion contracture.

CT findings in a dog with subacute myopathy and later fibrotic contracture of the infraspinatus muscle.

A 5-year-old Norwegian elkhound was referred due to an acute onset of lameness and persistent shoulder pain over a period of 3 weeks. Computed tomography demonstrated an enlarged, hypoattenuating right infraspinatus muscle with peripheral contrast enhancement and a nonenhancing center, without concurrent lesions in superficial structures or bones. The right infraspinatus muscle showed progressive atrophy on consecutive CT studies. The dog developed clinical symptoms compatible with fibrotic infraspinatus contracture 2 months after the initial presentation, and was treated with infraspinatus tenotomy. Histopathological diagnoses based on intraoperative biopsy samples were fibrotic muscle atrophy and muscle hypertrophy with regeneration.

Clinical presentation, sonographic features and treatment options of segmental stiff skin syndrome.

Segmental stiff skin syndrome is a rare genetic connective tissue disease, which is often misdiagnosed. High-frequency ultrasonography can represent a useful clinical adjunct in the differential diagnosis of this condition, in conjunction with the clinical and histopathological findings. Treatment options are limited and evidence is scarce. We present the clinical, sonographic and histological features of five paediatric patients diagnosed at our institution and discuss their response to treatment.

Atraumatic, Progressive, and Painful Elbow Contracture From a Ganglion Cyst.

Ganglion cysts are benign soft tissue tumors that often occur adjacent to joints or tendons. We report a case of an elbow joint ganglion cyst in a patient who presented with a painful, progressive elbow contracture. The patient was successfully treated with resection of the subbrachialis ganglion cyst combined with an anterior capsular release and an ulnar nerve decompression to recover elbow motion. This case highlights the value of advanced imaging in patients presenting with an atraumatic, painful, and progressive elbow contracture.

Pro-Fibrotic Phenotype in a Patient with Segmental Stiff Skin Syndrome via TGF-ß Signaling Overactivation.

Transforming growth factor ß (TGF-ß) superfamily signaling pathways are ubiquitous and essential for several cellular and physiological processes. The overexpression of TGF-ß results in excessive fibrosis in multiple human disorders. Among them, stiff skin syndrome (SSS) is an ultrarare and untreatable condition characterized by the progressive thickening and hardening of the dermis, and acquired joint limitations. SSS is distinct in a widespread form, caused by recurrent germline variants of FBN1 encoding a key molecule of the TGF-ß signaling, and a segmental form with unknown molecular basis. Here, we report a 12-year-old female with segmental SSS, affecting the right upper limb with acquired thickening of the dermis evident at the magnetic resonance imaging, and progressive limitation of the elbow and shoulder. To better explore the molecular and cellular mechanisms that drive segmental SSS, several functional studies on patient's fibroblasts were employed. We hypothesized an impairment of TGF-ß signaling and, consequently, a dysregulation of the associated downstream signaling. Lesional fibroblast studies showed a higher phosphorylation level of extracellular signal-regulated kinase 1/2 (ERK1/2), increased levels of nuclear factor-kB (NFkB), and a nuclear accumulation of phosphorylated Smad2 via Western blot and microscopy analyses. Quantitative PCR expression analysis of genes encoding key extracellular matrix proteins revealed increased levels of COL1A1, COL3A1, AGT, LTBP and ITGB1, while zymography assay reported a reduced metalloproteinase 2 enzymatic activity. In vitro exposure of patient's fibroblasts to losartan led to the partial restoration of normal transforming growth factor ß (TGF-ß) marker protein levels. Taken together, these data demonstrate that in our patient, segmental SSS is characterized by the overactivation of multiple TGF-ß signaling pathways, which likely results in altered extracellular matrix composition and fibroblast homeostasis. Our results for the first time reported that aberrant TGF-ß signaling may drive the pathogenesis of segmental SSS and might open the way to novel therapeutic approaches.

Lower Extremity Muscle Involvement in the Intermediate and Bethlem Myopathy Forms of COL6-Related Dystrophy and Duchenne Muscular Dystrophy: A Cross-Sectional Study.

Collagen VI-related dystrophies (COL6-RDs) and Duchenne muscular dystrophy (DMD) cause progressive muscle weakness and disability. COL6-RDs are caused by mutations in the COL6 genes (COL6A1, COL6A2 and COL6A3) encoding the extracellular matrix protein collagen VI, and DMD is caused by mutations in the DMD gene encoding the cytoplasmic protein dystrophin. Both COL6-RDs and DMD are characterized by infiltration of the muscles by fatty and fibrotic tissue. This study examined the effect of disease pathology on skeletal muscles in lower extremity muscles of COL6-RDs using timed functional tests, strength measures and qualitative/ quantitative magnetic resonance imaging/spectroscopy measures (MRI/MRS) in comparison to unaffected (control) individuals. Patients with COL6-RD were also compared to age and gender matched patients with DMD.Patients with COL6-RD presented with a typical pattern of fatty infiltration of the muscle giving rise to an apparent halo effect around the muscle, while patients with DMD had evidence of fatty infiltration throughout the muscle areas imaged. Quantitatively, fat fraction, and transverse relaxation time (T2) were elevated in both COL6-RD and DMD patients compared to unaffected (control) individuals. Patients with COL6-RD had widespread muscle atrophy, likely contributing to weakness. In contrast, patients with DMD revealed force deficits even in muscle groups with increased contractile areas.