PT Classroom - Snapping Scapula Syndrome ׀ by Jennifer Werwie, DPT

 

Jennifer Werwie, DPT, graduated with her Doctor of Physical Therapy degree from the University of Wisconsin-Madison. She received her BS degree in Kinesiology-Exercise Science from UW-Madison in 2008. Jennifer is also a certified personal trainer and fitness instructor. She is a Kenosha native and is an employee with United Hospital System where she primarily works in the outpatient PT setting.



 Snapping Scapula Syndrome

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Snapping scapula syndrome, or otherwise known as scapulothoracic crepitus, is a disorder in which scapulothoracic motion produces a snapping, grinding, thumping or popping sensation (1, 2). The sound is produced by a tactile-acoustic phenomenon of which there exist a multitude of potential causes ranging from bone spurs to muscular weakness to bursitis (2). While most patients experience “snapping scapula” as merely an annoying, asymptomatic crepitus, some do report a direct correlation between the sound and the onset of pain, which can result in a truly disabling condition (1).


It is important to note that the scapulothoracic joint is not a true synovial joint, yet merely an articulation between the anterior scapula and the posterior thoracic cage with no attachment by fibrous, synovial or cartilaginous tissue (3). This pseudo-joint between the scapula and the thoracic cage is the most incongruent articulation in the body, yet plays a crucial role in upper extremity function and provides a stable base for glenohumeral motion. This simultaneous, coordinated movement between the scapulothoracic and glenohumeral joint produces what is known as “scapulohumeral rhythm”, which consists of a motion ratio of 2° of glenohumeral elevation to every 1° of scapulothoracic elevation. Movement occurs along the plane of the scapula, which axes lie 30°-40° in frontal plane and 10°-20° anterior from vertical plane (4). Scapular function is mostly maintained through dynamic muscular control of the following surrounding musculature: pectoralis minor, coracobrachialis, serratus anterior, triceps, biceps, subscapularis, rhomboids, levator scapulae, trapezius, deltoid, supraspinatus, infraspinatus, teres minor, teres major, latissimus dorsi and omohyoid (5).


ETIOLOGY
Snapping scapula syndrome is thought to be caused by irregular motion between the scapula and thoracic ribcage (2-3, 6). This abnormal scapulothoracic motion can be the result from one of several causes (7-9):

Bony Prominences ¨ Luschka tubercle*
¨ Abnormal curvature of scapular superior angle
¨ Curling of vertebral border
¨ Irregularities of subscapular ribs
¨ Exostosis of subscapular ribs
Tumors ¨ Osteogenic sarcoma
¨ Osteochondroma
¨ Chondrosarcoma
Structural Spinal Abnormalities ¨ Scoliosis
¨ Thoracic kyphosis
Fracture ¨ Fracture malunion of ribs or scapula
(causing bony angulation and/or increased callus formation)
Dyskinesis: Loss of Dynamic Control ¨ Muscle overuse
¨ Muscle imbalance (often following nerve injury)
¨ Muscle atrophy (following nerve injury, trauma or prior operative treatment)
¨ Common in patients with shoulder instability, impingement and rotator cuff abnormalities
SICK Scapula Overuse Muscle Fatigue Syndrome:
¨ Scapular Malposition
¨ Inferior Medial Border Prominence
¨ Coracoid pain and malposition
¨ Dyskinesis of scapular movement

* Hook-shaped prominence at superomedial angle of scapula


EXAMINATION
Performing a thorough examination is vitally important to creating an appropriate treatment plan for individuals with snapping scapula syndrome. Below are some essential components to the subjective and objective examination of individuals who present with snapping scapula syndrome:

Subjective Exam (10):

  Symptomology:
  - Duration, frequency, severity, location of symptoms
  - MOI (mechanism of injury): insidious onset, with change in activity

..pattern, or associated with trauma

  - Associated symptoms: shoulder girdle and/or neck pain; weakness
  Psychosocial:
  - Occupation, activity level, hand dominance


Objective Exam (1, 7, 9):

  1. Postural conditions: thoracic kyphosis, forward-tilted head, rounded
....shoulders, abducted/forward-tipped scapulae, suboccipital

... extension

  2. Referred pain: cervical radiculopathy, neurological injuries
  3. Scapular asymmetry: scapular position in protraction versus

... retraction versus rotation; compensations with trunk shifting

....(observe with wall push-up)

  4. Palpation: focal tenderness of medial scapular border over

... superomedial and/or inferomedial bursae (patient position: adduct

....and internally rotate shoulder while touching opposite scapula)

  5. Static Strength: trapezius, rhomboids, levator scapulae, serratus

 ...anterior, latissimus dorsi, rotator cuff muscles, deltoids

  6. Dynamic strength: Presence of scapular winging: lateral winging

 ...(injury to long thoracic nerve that results in serratus anterior

... atrophy); shoulder drooping and forward rotation (injury to spinal

....accessory nerve that results in trapezius atrophy)

  7. Muscle flexibility: Hypertonia, myofascial tightness (common in

 ...upper trapezius and pectoralis minor), posterior capsular

....tightness; from chronic overuse or postures that hold muscles in

....shortened positions


TREATMENT
For the most part, scapulothoracic crepitus can be managed nonoperatively via treatment options such as physical therapy, anti-inflammatory medications, and corticosteroid injections (7, 12-14).

 
Physical Therapy. Goals of rehabilitation center on addressing postural issues, improving muscular strength, endurance and balance, and working on core strength. Kibler and McMullen (15) introduced the concept of a kinetic chain system that is built from the premise that efficient shoulder motion and muscle activation occur in a proximal-to-distal sequence, wherein shoulder function (distal) is dependent on thoracic spinal control (proximal). They centered their ten week shoulder rehabilitation program on the kinetic chain system and identified three stages of rehabilitation: acute, recovery and maintenance phases (15). Click here to see enlarged table.


 

The following are several key points to consider during the rehabilitation of snapping scapula (15-17):

  - Recognize and correct compensatory motions. Often from scapular

..muscular fatigue; key into trunk shifting with arm activity and correct

..via appropriate strengthening and postural awareness

  - Emphasize endurance training. Low intensity, high volume

  exercise for more functional training stimulus.

  - Utilize force couple with overhead movement. Co-contraction of

  serratus anterior and upper/lower trapezius in opposite directions to

  produce upward rotation of scapula.

  - Focus on proper, appropriate exercise progression. Isometric →

  isotonic → eccentrics; closed kinetic chain → open kinetic chain; for

  maximal restoration of functional strength

  - Address common associated issues/abnormalities: biceps

  tendinitis, thoracic outlet syndrome, rotator cuff pathology, and even

  headaches


Injections. Injections can be used diagnostically and therapeutically. Corticosteroid or local anesthetic can be injected into the scapulothoracic bursa for pain relief anywhere from six hours to fifteen months (17). While overall fairly safe, one potentially fatal complication of injections in this area is that of a pneumothorax (7). Recent technology is revealing the use of ultrasound-guided injections for increased accuracy of injections; however, clinical evidence for its efficacy has yet to be determined (18).


Operative Treatment. When all conservative resources have been exhausted, operative treatment should be considered for resection of osseous abnormalities and/or removal of inflamed bursae. Predictors of poor operative outcome include failure to receive temporary relief from injection therapy, inability to voluntarily reproduce snapping scapular sound, involvement in Workers’ Compensation claim or litigation, and documented nerve deficits (7). Three surgical approaches are open operative, arthroscopic and combined (19-20). Click here to see enlarged table.

 

Although previous case series have often found favorable results with operative treatment, the sample size has been small and techniques have been inconsistent and varied. Nonoperative treatment should continue to focus on addressing associated impairments and following an appropriate exercise progression through the various stages of rehabilitation. Indeed, great importance needs to be put on continued investigation to more specifically establish the most effective treatment strategies for this complex, multifactorial condition.

 

Last revised: April 20, 2013
by Jennifer Werwie, DPT


References:
1) Milch H. Partial scapulectomy for snapping of the scapula. J Bone Joint Surg Am. 1950;32:561-6.
2) Cuillo JV, Jones E. Subscapular bursitis: conservative and endoscopic treatment of “snapping scapula” or “washboard syndrome”. Orthop Trans. 1993; 16:740.
3) Poppen NK, Walker PS. Normal and abnormal motion of the shoulder. J Bone Joint Surg Am. 1976;58:195-201.
4) Voight ML, Thompson BC. The role of the scapula in rehabilitation of shoulder injuries. J Athl Train. 2000;35:364-372.
5) Della Valle CJ, Rokito AS, Birdzell MG, Zuckerman JD. Biomechanics of the shoulder. In: Norkin M. Frankel NH, eds. Basic Biomechanics of the Musculoskeletal System. Philadelphia, PA: Lippincott Williams & Wilkins; 2001:318-339.
6) Milch H, Burman MS. Snapping scapula and humerus varus. Report of six cases. Arch Surg. 1933;26:570-88.
7) Lazar MA, Kwon YW, Rokito AS. Snapping scapula syndrome. J Bone Joint Surg Am. 2009, 91:2251-2262.
8) Rockwood CA Jr, Matsen FA III, Wirth MA, Lippitt SB. The shoulder. 3rd ed. Philadelphia: Saunders; 2004.
9) Burkhart SS, Morgan CD, Kibler WB. The disabled throwing shoulder: spectrum of pathology Part III: The SICK scapula, scapular dyskinesis, the kinetic chain, and rehabilitation. Arthroscopy. 2003;19:641-61.
10) Carlson HL, Haig AJ, Stewart DC. Snapping scapula syndrome: three case
reports and an analysis of the literature. Arch Phys Med Rehabil. 1997;78:506-11.
11) Warner JJ, Micheli LJ, Arslanian LE, Kennedy J, Kennedy R. Scapulothoracic motion in normal shoulders and shoulders with glenohumeral instability and impingement syndrome. A study using Moir´e topographic analysis. Clin Orthop Relat Res. 1992;285:191-9.
12) Millett PJ, Pacheco IH, Gobezie R, Warner JJP. Management of recalcitrant scapulothoracic bursitis: endoscopic scapulothoracic bursectomy and scapuloplasty. Tech Shoulder Elbow Surg. 2006;7:200-5.
13) Groh GI, Simoni M, AIIen T, Dwyer T, Heckman MM, Rockwood CA Jr. Treatment of snapping scapula with a periscapular muscle strengthening program [abstract]. J Shoulder Elbow Surg. 1996;5(2-Pt 2):S6.
14) Kibler WB, Livingston B. Closed-chain rehabilitation for upper and lower extremities. J Am Acad Orthop Surg. 2001;9:412-21.
15) Kibler WB, McMullen J. Scapular dyskinesis and its relation to shoulder pain. J Am Acad Orthop Surg. 2003;11:142-51
16) McQuade K, Dawson J, Schmidt G. Scapulothoracic muscle fatigue associated with alterations in scapulohumeral rhythm. J Orthop Sports Phys Ther. 1998;28:74-80.
17) Manske RC, Reiman MP, Stovak ML. Nonoperative and operative management of snapping scapula. Am J Sports Med. 2004;32(6)1554-1565.
18) Saboeiro GR, Sofka CM. Imaging-guided treatment of scapulothoracic bursitis. HSS J. 2007;3:213-5.
19) Nicholson GP, Duckworth MA. Scapulothoracic bursectomy for snapping scapula syndrome. J Shoulder Elbow Surg. 2002;11:80-5.
20) McCluskey GM III, Bigliani LU. Surgical management of refractory scapulothoracic bursitis. Orthop Trans. 1991;15:801.

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