The Heel Complex: Anatomy, Imaging, Pathologic Conditions, and Treatment.

The differential diagnosis for heel pain is broad but primarily involves abnormalities of the Achilles tendon, calcaneus, and plantar fascia. Achilles tendon disorders include tendinosis, tendinitis, and partial or complete tears. Tendinosis refers to tendon degeneration, while tendinitis is inflammation after acute overload. Untreated tendinosis can progress to partial or complete tears. Tendon disorders can be accompanied by paratenonitis or inflammation of the loose sheath enclosing the tendon. Initial management involves rehabilitation and image-guided procedures. Operative management is reserved for tendon tears and includes direct repair, tendon transfer, and graft reconstruction. The calcaneus is the most commonly fractured tarsal bone. The majority of fractures are intra-articular; extra-articular fractures, stress or insufficiency fractures, medial process avulsion, and neuropathic avulsion can also occur. Posterosuperior calcaneal exostosis or Haglund deformity, retrocalcaneal bursitis, and insertional Achilles tendinosis form the characteristic triad of Haglund syndrome. It is initially managed with orthotics and physiotherapy. Operative management aims to correct osseous or soft-tissue derangements. The plantar fascia is a strong fibrous tissue that invests the sole of the foot and contributes to midfoot stability. Inflammation or plantar fasciitis is the most common cause of heel pain and can be related to overuse or mechanical causes. Acute rupture is less common but can occur in preexisting plantar fasciitis. Conservative treatment includes footwear modification, calf stretches, and percutaneous procedures. The main operative treatment is plantar fasciotomy. Plantar fibromatosis is a benign fibroblastic proliferation within the fascia that can be locally aggressive and is prone to recurrence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Shoulder and Elbow Injuries in Adult Overhead Throwers: Imaging Review.

Overhead throwing, particularly in baseball, subjects the shoulder and elbow to various unique injuries. Capsular contracture following repetitive external rotation shifts the humeral head posterosuperiorly, predisposing to glenohumeral internal rotation deficit (GIRD), Bennett, posterosuperior internal impingement (PSI), and superior labrum anterior-posterior (SLAP) lesions. GIRD represents loss of internal rotation at the expense of external rotation. Bennett lesion represents ossification of the posteroinferior glenohumeral ligament due to repetitive traction. PSI manifests with humeral head cysts and "kissing" tears of the posterosuperior cuff and labrum. Scapular dysfunction contributes to symptoms of PSI and predisposes to labral or rotator cuff disease. "Peel-back" or SLAP lesions occur when torsional forces detach the biceps-labral anchor from the glenoid. Finally, disorders of the anterior capsule, latissimus dorsi, teres major, and subscapularis are well recognized in overhead throwers. At the elbow, injuries typically involve the medial-sided structures. The ulnar collateral ligament (UCL) is the primary static restraint to valgus stress and can be thickened, attenuated, ossified, and/or partially or completely torn. Medial epicondylitis can occur with tendinosis, partial tear, or complete rupture of the flexor-pronator mass and can accompany UCL tears and ulnar neuropathy. Posteromedial impingement (PMI) and valgus extension overload syndrome are related entities that follow abundant valgus forces during late cocking or acceleration, and deceleration. These valgus stresses wedge the olecranon into the olecranon fossa, leading to PMI, osteophytes, and intra-articular bodies. Other osseous manifestations include olecranon stress fracture and cortical thickening of the humeral shaft. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging of the Acromioclavicular Joint: Anatomy, Function, Pathologic Features, and Treatment.

The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial articulation between the clavicle and the acromion, contains a meniscus-like fibrous disk that is prone to degeneration. The acromioclavicular capsule and ligaments stabilize the joint in the horizontal direction, while the coracoclavicular ligament complex provides vertical stability. Dynamic stability is afforded by the deltoid and trapezius muscles during clavicular and scapular motion. The acromioclavicular joint is susceptible to a broad spectrum of pathologic entities, traumatic and degenerative disorders being the most common. Acromioclavicular joint injury typically affects young adult males and can be categorized by using the Rockwood classification system as one of six types on the basis of the direction and degree of osseous displacement seen on conventional radiographs. MRI enables the radiologist to more accurately assess the regional soft-tissue structures in the setting of high-grade acromioclavicular separation, helping to guide the surgeon's selection of the appropriate management. Involvement of the acromioclavicular joint and its stabilizing ligaments is also important for understanding and classifying distal clavicle fractures. Other pathologic processes encountered at this joint include degenerative disorders; overuse syndromes; and, less commonly, inflammatory arthritides, infection, metabolic disorders, and developmental malformations. Treatment options for acromioclavicular dysfunction include conservative measures, resection arthroplasty for recalcitrant symptoms, and surgical reconstruction techniques for stabilization after major trauma.