MRI features of ERSA (exercise-related signal abnormality) lesions in professional soccer players.

OBJECTIVE: This study aims to describe the prevalence, anatomy and morphology of ERSA (exercise-related signal abnormality) lesions, a previously undescribed pattern of muscle signal changes on MRI in professional soccer players with suspected acute thigh muscle injury. METHODS: A multicenter retrospective review was performed of 287 MRIs of professional soccer players referred for suspected acute thigh injury from August 2017 to February 2020. MR images were reviewed for muscle signal abnormalities corresponding to a peritendinous ovoid region or a subfascial ring of faint increased signal on fluid-sensitive MR images. Imaging features including anatomical site, morphology, and craniocaudal length were recorded. Concomitant acute muscle injury was graded in accordance with the British Athletics Muscle Injury Classification (BAMIC). RESULTS: ERSA lesions comprising a peritendinous ovoid region, a subfascial ring, or both, were identified in 40 muscles across 31/287 studies (10.8%). These lesions had a mean length of 15.8 cm and were predominantly located in the proximal or mid-portions of muscles. Affected muscles were rectus femoris (n = 22), adductor longus (n = 11), semitendinosus (n = 6) and biceps femoris (n = 1). 21/31 studies (67.7%) had a BAMIC grade 1-4 injury in a separate muscle, which were largely (81%) in a separate anatomic compartment or contralateral. CONCLUSION: ERSA lesions were evident on MRI in 10.8% of our cohort of professional soccer players referred for suspected acute thigh muscle injury. Characteristic morphology and the longitudinal length (mean 15.8 cm) distinguish ERSA lesions from recognized patterns of acute muscle injury.

MRI findings of tibialis anterior friction syndrome: a mimic of tibial stress injury.

OBJECTIVE: To describe a distinct constellation of MRI demonstrated soft tissue abnormalities centred around the tibialis anterior tendon in a subset of patients presenting as suspected tibial stress injury. MATERIALS AND METHODS: A retrospective review was performed of the clinical and MRI imaging findings from 5 selected patients referred for MRI with suspected tibial stress injury. MRI studies at presentation of each case were systematically reviewed for peritendinous fluid, tibialis anterior tendon change, tibialis anterior muscle and myotendinous junction oedema, periosteal oedema over the tibia and tibial marrow oedema. RESULTS: All 5 cases were athletes (3 soccer players, 2 runners) of between 20 and 40 years of age. On MRI, all 5 cases demonstrated peritendinous fluid around an intact tibialis anterior tendon. This fluid was maximal at the junction of mid and distal thirds of the lower leg, and extended down to the superior extensor retinaculum, with a mean cranio-caudal length of 13 cm (range 8-17 cm). Associated oedema was present in the surrounding subcutaneous tissue, tibial periosteum and distal tibialis anterior musculotendinous junction. CONCLUSION: Peritendinous fluid around an intact tibialis anterior tendon over the mid-to-distal third tibia, with surrounding subcutaneous, periosteal and tibialis anterior myotendinous junction oedema is demonstrable on MRI in a subset of patients presenting as suspected tibial stress injury. A friction syndrome of tibialis anterior between the superior extensor retinaculum and the anterior tibia is proposed as the aetiology of this entity.

The frondiform ligament sling: a sonographic landmark for injection into the sinus tarsi.

Localisation and injection of the sinus tarsi can be challenging, particularly for the less experienced musculoskeletal sonographer/practitioner. The inferior extensor retinaculum arises from the sinus tarsi in the form of three roots (medial, intermediate and lateral) which are collectively termed the frondiform ligament. This is readily identified on ultrasound and can be used as a reference point to aid the safe delivery of injectate material into the sinus tarsi. This article describes the technique and its anatomical basis.

Efficacy of ultrasound-guided steroid injections for pain management of midfoot joint degenerative disease.

OBJECTIVE: To examine the efficacy of ultrasound (US)-guided injections for midfoot joint degenerative changes. MATERIALS AND METHODS: The US images and radiographs of 63 patients with midfoot joint degenerative changes were retrospectively reviewed. In those patients who had US-guided intra-articular steroid injection, the response to the injection was recorded by reviewing the 2-week pain diaries and clinical notes. Partial or complete pain relief was defined as a positive response and the same or increased level of pain as a negative response to the injection. RESULTS: Fifty-nine (59/63, 93.6%) patients with midfoot joint degenerative changes received US-guided injection. The majority of patients had a positive response up to 3 months post-injection (78.4% still experiencing pain relief at 2 weeks, 57.5% at 3 months and fewer than 15% of patients further than 3 months post-injection). The number of positive therapeutic responses did not differ significantly between patients with diagnostic and non-diagnostic response (p = 0.2636). CONCLUSIONS: US-guided intra-articular injections for midfoot degenerative changes can have a good therapeutic result in the majority of patients up to 3 months post-injection. Therapeutic response cannot be predicted by a positive diagnostic response.

Technical report: dynamic assessment of plantar fasciitis and plantar fascia tears utilising dorsiflexion of the great toe.

Discrimination between plantar fasciitis and partial tears of the plantar fascia can be difficult on ultrasound given laxity of the plantar fascia in the region of its calcaneal insertion and anisotropy. Dynamic assessment with great toe dorsiflexion can improve visualisation of the proximal portion of the plantar fascia on ultrasound, by straightening the plantar fascia due to the windlass mechanism. This article describes the technique and its anatomical basis.