Can Achilles tendon xanthoma be distinguished from Achilles tendinopathy using Dixon method MRI? A cross-sectional exploratory study.

BACKGROUND: Familial hypercholesterolemia is a genetic condition characterized by life-long elevations of plasma low-density lipoprotein cholesterol. In addition to life-threatening cardiovascular complications, intratendinous cholesterol deposits (xanthomas) can lead to pain and tendon thickening, particularly in the Achilles. Clinical detection of xanthomas currently relies upon visual assessment and palpation, or ultrasound-based measures of tendon thickening or echotexture. Misdiagnosis of xanthoma can delay the commencement of potentially life-saving lipid-lowering therapy. Our primary purpose was to determine whether analysis of separated fat and water magnetic resonance images may be able to differentiate between xanthomatic and nonxanthomatic Achilles tendons through quantification of intratendinous fat content. The main hypothesis was that Achilles tendon xanthomas will demonstrate greater lipid content than Achilles tendinopathy or healthy control tendons. METHODS: Bilateral MRI scans of Achilles tendons from 30 participants (n = 10 Achilles tendon xanthoma, n = 10 Achilles overuse tendinopathy, n = 10 healthy controls) were analyzed for total lipid content using the Dixon method of fat and water signal separation. Secondary outcome measures included tendon water content, as well as ultrasound characterization of tendon tissue organization and thickness. RESULTS: Fat content was greater in Achilles tendon xanthomas compared to the tendinopathy (p < 0.0001) and control groups (p < 0.0001). Water content was also greater in Achilles tendon xanthomas compared to the tendinopathy (p < 0.0001) and control groups (p = 0.0002). Ultrasound tissue characterization revealed worse tissue organization in Achilles tendon xanthoma tendons compared to Achilles tendinopathy (p < 0.05) but demonstrated largely overlapping distributions. Achilles tendon xanthoma tendons were, on average, significantly thicker than the tendons of the other two groups (p < 0.01 and p < 0.001, respectively). CONCLUSION: MRI-derived measures of Achilles tendon fat content may be able to distinguish xanthomas from control and tendinopathic tissue. Dixon method MRI warrants further evaluation in an adequately powered study to develop and test clinically relevant diagnostic thresholds.

Mid-term results of a prospective randomised controlled trial comparing large-head metal-on-metal hip replacement to hip resurfacing using patient-reported outcome measures and objective functional task-based outcomes.

BACKGROUND: The early outcomes of large head-metal-on-metal total hip arthroplasty (MoM THA) are compromised by adverse local tissue reaction to metal debris. This study is the mid-term follow-up of a prospective randomised control trial (pRCT) comparing MoM THA to MoM HR. We sought to answer whether there was a difference between MoM THA and MoM HR at mid-term follow-up in the implant survival; patient-reported outcome measures (PROMs); and when performing objective functional tasks? METHODS: A total of 104 patients were studied. Of these 56 had MoM THA (50 male) and 48 had HR (43 male). Mean age at surgery was 52 years in both groups.We reviewed this cohort at mid-term follow-up [minimum 8 years (mean 9 years; range 8-10; SD 0.7)]. PROMs that were completed were OHS, WOMAC, SF-12, and the UCLA. For objective functional task-based outcomes, gait parameters for operated legs were assessed in a subgroup of 17 patients with high UCLA. RESULTS: Revision rate in MoM THA group was 7/56 (12.5%) and in the HR group was 1/48 (2.1%). Overall revision rate at minimum 8-year follow-up was 7.7% (8 of 104 patients). PROMs data comparing MoM THA versus HR showed no difference between the groups. 4 (8.5%) of the non-revised (47) HR patients had WOMAC function or pain score below 70. 3 (6.4%) patients had both pain and function scores <70. In the THA group, 5 (10.2%) of the non-revised (49) patients had WOMAC pain or function scores <70. 3 (6.1%) patients had both pain and function scores <70. The comparison of HA versus THA showed several gait parameters in the HR group to be better but not statistically significant (p > 0.05 Mann-Whitney U-test). CONCLUSIONS: At mid-term follow-up, the revision rate of MoM articulation for THA is high (7.7%), being higher in large head MoM total hips versus resurfacing. Overall probability of 10-year survival is 92.3% (KM analysis, 95% for MoM THA and 98% for HR). The HR group had better functional parameters on gait-based tasks compared to THA group but this difference did not reach statistical significance.

The Influence of Maturity Status on Muscle Architecture in School-Aged Boys.

PURPOSE: To determine the differences in muscle architecture of the lower limb in pre-peak height velocity (PHV), circa-PHV, and post-PHV boys. METHOD: Muscle architecture variables from both the gastrocnemius medialis (GM) and vastus lateralis (VL) were derived from ultrasonographic images in 126 school-aged boys. One-way analysis of variance using Bonferroni post hoc comparisons was employed to determine between-group differences, and effect sizes were calculated to establish the magnitude of these differences. RESULTS: All muscle architecture variables showed significant small to large increases from pre-PHV to post-PHV, excluding GM fascicle length (d = 0.59-1.39; P < .05). More discrete between-group differences were evident as GM and VL muscle thickness, and physiological thickness significantly increased between pre-PHV and circa-PHV (d > 0.57; P < .05); however, only the VL muscle thickness and physiological thickness increased from circa-PHV to post-PHV (d = 0.68; P < .05). The post-PHV group also showed larger GM pennation angles than the circa-PHV group (d = 0.59; P < .05). CONCLUSION: The combined results showed that maturation is associated with changes in muscle morphology. These data quantify that the maturity-related changes in muscle architecture variables provide a reference to differentiate between training-induced adaptations versus changes associated with normal growth and maturation.

Transverse tendon stiffness is reduced in people with Achilles tendinopathy: A cross-sectional study.

OBJECTIVES: The objective of the current cross-sectional study was to examine Achilles tendon transverse stiffness in a group of recreational runners with Achilles tendinopathy, in comparison to an asymptomatic group of runners with similar training history. We also aimed to determine the between-week intra-individual reliability of this measurement technique. DESIGN: Cross-sectional cohort study. METHODS: A hand-held dynamometer was used to assess the transverse stiffness of the Achilles tendon (AT) in twenty-five recreational runners. In ten people with midportion Achilles tendinopathy (5 men, 5 women), measurements were taken directly over the most symptomatic location. In 15 people who were free of AT symptoms (7 men, 8 women), measurements were taken at an equivalent location on the tendon. Participants returned after one week to determine measurement reliability (intra-class correlation coefficient/ICC and minimum detectable change/MDC95). We also collected information about people's tendon loading activities, tendon thickness (ultrasound mesaurement), and symptoms (Victorian Institute of Sports Assessment-Achilles / VISA-A score). RESULTS: The AT transverse stiffness was lower in people with Achilles tendinopathy (777 N/m ± 86) compared to those who were asymptomatic (873 N/m ± 72) (p < 0.05). AT transverse stiffness was negatively correlated with age and tendon thickness, and positively correlated with VISA-A score and waist circumference. Reliability was good, with ICC of 0.81 in people with tendinopathy and 0.80 in healthy controls, and an MDC95 of 118 and 87N/m in these two respective groups. CONCLUSIONS: Transverse Achilles tendon stiffness can be reliably measured in people with midportion Achilles tendinopathy, and appears to be lower in people who are older, more symptomatic, and with more extensive tendon thickening. The potential clinical utility of monitoring tendon stiffness in the management of tendon injuries merits further study.

Feasibility of using a hand-held device to characterize tendon tissue biomechanics.

OBJECTIVES: To examine the feasibility of using the MyotonPRO digital palpation device in measuring the transverse stiffness of tendon tissue. DESIGN: Experimental study. METHODS: The MyotonPRO was used to measure the stiffness and related properties of ballistics gel in comparison with an external materials testing system (PCB electronics). The device was then used to measure the same properties of avian Achilles tendons before and after the removal of the overlying skin and subcutaneous tissue. Next, the test-retest reliability of the Achilles and patellar tendons was determined in humans. Finally, the stiffness of the Achilles tendon was measured before and after competitive running races of varying distances (10, 21 and 42 km, total number of athletes analyzed = 66). RESULTS: The MyotonPRO demonstrated a high degree of consistency when testing ballistics gel with known viscoelastic properties. The presence of skin overlying the avian Achilles tendon had a statistically significant impact on stiffness (p<0.01) although this impact was of very small absolute magnitude (with skin; 728 Nm ±17 Nm, without skin; Nm 704 Nm ±7 Nm). In healthy adults of normal body mass index (BMI), the reliability of stiffness values was excellent both for the patellar tendon (ICC, 0.96) and the Achilles tendon (ICC,0.96). In the the field study, men had stiffer tendons than women (p<0.05), and the stiffness of the Achilles tendon tended to increase following running (p = 0.052). CONCLUSIONS: The MyotonPRO can reliably determine the transverse mechanical properties of tendon tissue. The measured values are influenced by the presence of overlying skin, however this does not appear to compromise the ability of the device to record physiologically and clinically relevant measurements.

Can Shockwave Therapy Improve Tendon Metabolism?

Shockwave treatments are commonly used in the management of tendon injuries and there is increasing evidence for its clinical effectiveness. There is a paucity of fundamental (in vivo) studies investigating the biological action of shockwave therapy. Destruction of calcifications, pain relief and mechanotransduction-initiated tissue regeneration and remodeling of the tendon are considered to be the most important working mechanisms. The heterogeneity of systems (focussed shockwave therapy vs. radial pressurewave therapy), treatment protocols and study populations, and the fact that there seem to be responders and non-responders, continue to make it difficult to give firm recommendations with regard to the most optimal shockwave therapy approach. Specific knowledge with regard to the effects of shockwave therapy in patients with metabolic tendon disorders is not available. Further fundamental and clinical research is required to determine the value of shockwave therapy in the management of tendinopathy.

The effectiveness of extracorporeal shock wave therapy in lower limb tendinopathy: a systematic review.

BACKGROUND: There is accumulating evidence for the effectiveness of extracorporeal shock wave therapy (ESWT) when treating lower limb tendinopathies including greater trochanteric pain syndrome (GTPS), patellar tendinopathy (PT), and Achilles tendinopathy (AT). PURPOSE: To evaluate the effectiveness of ESWT for lower limb tendinopathies. STUDY DESIGN: Systematic review and meta-analysis. METHODS: PubMed (Medline), Embase, Web of Knowledge, Cochrane, and CINAHL were searched from inception to February 2013 for studies of any design investigating the effectiveness of ESWT in GTPS, PT, and AT. Citation tracking was performed using PubMed and Google Scholar. Animal and non-English language studies were excluded. A quality assessment was performed by 2 independent reviewers, and effect size calculations were computed when sufficient data were provided. RESULTS: A total of 20 studies were identified, with 13 providing sufficient data to compute effect size calculations. The energy level, number of impulses, number of sessions, and use of a local anesthetic varied between studies. Additionally, current evidence is limited by low participant numbers and a number of methodological weaknesses including inadequate randomization. Moderate evidence indicates that ESWT is more effective than home training and corticosteroid injection in the short (<12 months) and long (>12 months) term for GTPS. Limited evidence indicates that ESWT is more effective than alternative nonoperative treatments including nonsteroidal anti-inflammatory drugs, physical therapy, and an exercise program and equal to patellar tenotomy surgery in the long term for PT. Moderate evidence indicates that ESWT is more effective than eccentric loading for insertional AT and equal to eccentric loading for midportion AT in the short term. Additionally, there is moderate evidence that combining ESWT and eccentric loading in midportion AT may produce superior outcomes to eccentric loading alone. CONCLUSION: Extracorporeal shock wave therapy is an effective intervention and should be considered for GTPS, PT, and AT particularly when other nonoperative treatments have failed.