Acromioclavicular joint disorders
- Scott M Koehler, MD
Scott M Koehler, MD
- Physician, Sports Medicine Specialist
- Allina Medical Clinic, Northfield
- Section Editor
- Karl B Fields, MD
Karl B Fields, MD
- Editor-in-Chief — Primary Care Sports Medicine (Adolescents and Adults)
- Section Editor — Biomechanics, Rehabilitation, and Recovery; Sports-Related Injuries; Symptom Assessment and Physical Examination
- Professor of Family Medicine and Sports Medicine
- University of North Carolina at Chapel Hill
- Deputy Editors
- Jonathan Grayzel, MD, FAAEM
Jonathan Grayzel, MD, FAAEM
- Senior Deputy Editor — Adult and Pediatric Emergency Medicine
- Senior Deputy Editor — Primary Care Sports Medicine (Adolescents and Adults)
- Assistant Professor of Emergency Medicine
- University of Massachusetts Medical School
- Susanna I Lee, MD, PhD
Susanna I Lee, MD, PhD
- Deputy Editor — Radiology
- Associate Professor of Radiology
- Harvard Medical School
- Massachusetts General Hospital
Acromioclavicular (AC) joint disorders can be classified into acute injuries, repetitive strain injuries, degenerative conditions, and other conditions. The diagnosis of acute AC joint injury (sometimes referred to as a sprain or "separated" shoulder) is often straightforward due to the presence of focal tenderness, swelling, and deformity.
AC joint disorders from overuse, inflammation, or chronic degeneration can be more difficult to diagnose, particularly if concomitant shoulder problems exist. This topic will review the evaluation and management of AC joint disorders. AC joint injuries are discussed separately. (See "Acromioclavicular joint injuries ("separated" shoulder)".)
ANATOMY AND PATHOPHYSIOLOGY
The acromioclavicular (AC) joint unites the distal clavicle and the acromion of the scapula. It contains an intra-articular disc, a synovial membrane, and articular cartilage that cover the distal end of the clavicle and the opposing surface of the acromion . The AC joint is supported by a ligament complex, as well as surrounding fascia and muscles (picture 1). The anatomy and biomechanics of the AC joint are described in greater detail separately. (See "Acromioclavicular joint injuries ("separated" shoulder)", section on 'Anatomy and biomechanics'.)
The AC joint normally degenerates over several decades but in most cases, remains asymptomatic. The joint gradually narrows as the articular disc and chondral cartilage wear away. This degeneration is often more rapid than in other joints, with the articular disc beginning to break down in the second decade of life . By the age of 40, most patients have narrowing of the joint space and possibly other degenerative findings .
EVALUATION OF THE PAINFUL AC JOINT
The patient with a painful acromioclavicular (AC) joint often complains of focal shoulder pain, and when asked to point to the most painful spot typically indicates the top of the shoulder. However, pain arising from the AC joint may be more generalized since the joint is innervated by branches of both the axillary and lateral pectoral nerves. Symptoms arising from the AC joint may be felt anywhere from the base of the neck and trapezius region to the lateral deltoid .
- Renfree KJ, Wright TW. Anatomy and biomechanics of the acromioclavicular and sternoclavicular joints. Clin Sports Med 2003; 22:219.
- Montellese P, Dancy T. The acromioclavicular joint. Prim Care 2004; 31:857.
- Gerber C, Galantay RV, Hersche O. The pattern of pain produced by irritation of the acromioclavicular joint and the subacromial space. J Shoulder Elbow Surg 1998; 7:352.
- Bianchi, S, Martinoli, C. Ultrasound of the Muscoskeletal system, 1st, Baert, AL, Knauth, M, Sartor, K (Eds), Springer, New York 2007. p.206.
- Walton J, Mahajan S, Paxinos A, et al. Diagnostic values of tests for acromioclavicular joint pain. J Bone Joint Surg Am 2004; 86-A:807.
- Hegedus EJ, Goode A, Campbell S, et al. Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests. Br J Sports Med 2008; 42:80.
- Chronopoulos E, Kim TK, Park HB, et al. Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. Am J Sports Med 2004; 32:655.
- O'Brien SJ, Pagnani MJ, Fealy S, et al. The active compression test: a new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med 1998; 26:610.
- Zanca P. Shoulder pain: involvement of the acromioclavicular joint. (Analysis of 1,000 cases). Am J Roentgenol Radium Ther Nucl Med 1971; 112:493.
- Shaffer BS. Painful conditions of the acromioclavicular joint. J Am Acad Orthop Surg 1999; 7:176.
- Finnoff JT, Smith J, Peck ER. Ultrasonography of the shoulder. Phys Med Rehabil Clin N Am 2010; 21:481.
- Lento PH, Strakowski JA. The use of ultrasound in guiding musculoskeletal interventional procedures. Phys Med Rehabil Clin N Am 2010; 21:559.
- Sabeti-Aschraf M, Ochsner A, Schueller-Weidekamm C, et al. The infiltration of the AC joint performed by one specialist: ultrasound versus palpation a prospective randomized pilot study. Eur J Radiol 2010; 75:e37.
- Ucuncu F, Capkin E, Karkucak M, et al. A comparison of the effectiveness of landmark-guided injections and ultrasonography guided injections for shoulder pain. Clin J Pain 2009; 25:786.
- Rudzki JR, Matava MJ, Paletta GA Jr. Complications of treatment of acromioclavicular and sternoclavicular joint injuries. Clin Sports Med 2003; 22:387.
- Bianchi S, Martinoli C. Ultrasound of the Muscoskeletal system, 1st ed, Baert AL, Knauth M, Sartor K (Eds), Springer, New York 2007. p.206.
- Peck E, Lai JK, Pawlina W, Smith J. Accuracy of ultrasound-guided versus palpation-guided acromioclavicular joint injections: a cadaveric study. PM R 2010; 2:817.
- Pichler W, Weinberg AM, Grechenig S, et al. Intra-articular injection of the acromioclavicular joint. J Bone Joint Surg Br 2009; 91:1638.
- Bisbinas I, Belthur M, Said HG, et al. Accuracy of needle placement in ACJ injections. Knee Surg Sports Traumatol Arthrosc 2006; 14:762.
- Cahill BR. Osteolysis of the distal part of the clavicle in male athletes. J Bone Joint Surg Am 1982; 64:1053.
- Schwarzkopf R, Ishak C, Elman M, et al. Distal clavicular osteolysis: a review of the literature. Bull NYU Hosp Jt Dis 2008; 66:94.
- Buss DD, Watts JD. Acromioclavicular injuries in the throwing athlete. Clin Sports Med 2003; 22:327.
- Pensak M, Grumet RC, Slabaugh MA, Bach BR Jr. Open versus arthroscopic distal clavicle resection. Arthroscopy 2010; 26:697.
- Rabalais RD, McCarty E. Surgical treatment of symptomatic acromioclavicular joint problems: a systematic review. Clin Orthop Relat Res 2007; 455:30.
- Jacob AK, Sallay PI. Therapeutic efficacy of corticosteroid injections in the acromioclavicular joint. Biomed Sci Instrum 1997; 34:380.
- Hossain S, Jacobs LG, Hashmi R. The long-term effectiveness of steroid injections in primary acromioclavicular joint arthritis: a five-year prospective study. J Shoulder Elbow Surg 2008; 17:535.
- Freedman BA, Javernick MA, O'Brien FP, et al. Arthroscopic versus open distal clavicle excision: comparative results at six months and one year from a randomized, prospective clinical trial. J Shoulder Elbow Surg 2007; 16:413.
- Iyengar KP, Gudena R, Chitgopkar SD, et al. Primary septic arthritis of the acromio-clavicular joint: case report and review of literature. Arch Orthop Trauma Surg 2009; 129:83.
- Lehtinen JT, Kaarela K, Belt EA, et al. Incidence of acromioclavicular joint involvement in rheumatoid arthritis: a 15 year endpoint study. J Rheumatol 1999; 26:1239.
- ANATOMY AND PATHOPHYSIOLOGY
- EVALUATION OF THE PAINFUL AC JOINT
- - Inspection
- - Palpation
- - Shoulder range of motion
- - Neurovascular function
- - Special maneuvers for the AC joint
- Cross body adduction test
- AC shear testing
- Active compression test
- Diagnostic imaging
- - Plain radiographs
- - Bone scan
- - Ultrasound
- - Magnetic resonance imaging
- Diagnostic injection
- DIAGNOSTIC APPROACH
- SPECIFIC DISORDERS
- Acromioclavicular joint injuries
- Overuse injuries
- Osteolysis of the distal clavicle
- Painful degeneration of the AC joint
- Other conditions
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS