Biomechanics/Anatomy

pic.png 7499.jpg

http://www.mountnittany.org/articles/healthsheets/6918
The Glenohumeral joint is similar to a golf ball and tee in structure. It allows for a large arc of movement that leaves it susceptible to instability. Laxity is normally asymptomatic and is a physiologic motion that is necessary for proper glenohumeral movement while instability is an abnormal symptomatic motion of the glenohumeral joint. Stability as well as mobility of the glenohumeral joint is provided through static and dynamic stabilizers.

Static stabilizers include capsular ligaments, the glenoid labrum, articular cartilage surface contact forces, and negative intra-articular pressure. The ligaments that are responsible for stability are the superior glenohumeral ligament (SGHL), the middle glenohumeral ligament (MGHL), and the inferior glenohumeral ligament (IGHL). The SGHL limits anterior and inferior translation of the humerus when adducted. The MGHL limits anterior translation in the mid-range of shoulder abduction. The IGHL is the primarily responsible for limiting anterior subluxation of the humeral head when the shoulder is abducted beyond 45°. Dynamic stabilization is provided by the rotator cuff muscles which add a compressive effect as well as the long head of the biceps and the muscles that stabilize the scapula.


Mechanism of Injury



Instability can be classified based on frequency, etiology, direction and degree. Anterior instability is the most common type of instability, accounting for roughly 90% of all dislocations. The rate of incidence increases for men as well as contact athletes. The mechanism responsible for an anterior dislocation is a forced external rotation and abduction of the humerus. This is most often seen in athletes that reach up to block a pass as in basketball or football. Microtrauma of the shoulder can be caused by repetitive overhead activities. A fall onto an elevated outstretched arm and a direct force to the posterior humeral head also account for mechanisms of injury.


Richard+Simmons+2010+World+Fitness+Day+HHBrXqjbMNVl.jpg 92323995_crop_650x440.jpg
http://bleacherreport.com/articles/475243-sabans-alabama-is-ranked-1-but-dont-dismiss-urban-meyers-florida-gators

Signs and Symptoms

Obtaining an accurate diagnosis of glenohumeral instability can be difficult, therefore several points must be considered when assessing the patient. A thorough history and clinical examination are necessary as radiographs typically do not provide additional information. Asymptomatic shoulder laxity must be differentiated from symptomatic instability. Other pathological conditions may be present, such as rotator cuff impingement. No single test may be used to diagnose glenohumeral instabilities.

A thorough subjective evaluation will assist the examiner in identifying the often vague symptoms associated with nontraumatic glenohumeral instability. Symptoms may include activity related global pain, aching, looseness and reports of slipping of the joint. Transient neurological symptoms may be reported and must be differentiated from cervical radiculopathy and thoracic outlet syndrome. Anterior instability may be present with pain with overhead activities or when the shoulder is in an abducted and externally rotated position.
Patients with glenohumeral instability often present with scapular dyskinesia, including winging and protraction. Inspection of both shoulders is necessary to identify differences between the symptomatic and asymptomatic sides. The examination should begin with the asymptomatic shoulder.

Ligamentous hyperextensibility should be assessed using the Beighton scale. A score ≥ 4 out of 9 indicates generalized joint laxity.

Beighton.JPG



Orthopedic tests used to identify laxity may not be used alone to diagnose instability. It is the replication of the patient’s sense of instability that differentiates asymptomatic laxity to laxity with instability. The sulcus sign is used to assess inferior laxity. Laxity may be graded according to the inferior translation of the head of the humerus. Movement < 1cm is graded as 1, 1-2 cm movement is graded as 2 and > 2 cm is graded as 3.
Sulcus.JPG


The presence of pain, dysesthesia or apprehension with the sulcus sign may indicate instability. Anterior laxity may be assessed with passive external rotation. The presence of passive external rotation >90 indicated hyperlaxity. The load and shift test and the anterior and posterior drawer tests examine the amount of translation present when the ligaments are not under tension.

Load_and_Shift.JPG
Provocation tests such as the anterior apprehension test, the relocation test and the posterior apprehension test may be more sensitive since they replicate the patient’s symptoms with instability.

Treatment:

Duration-how long would you typically see this patient?
Depends on severity of the instability and whether or not there was a surgical intervention
Non-surgical: 6-8 weeks, Surgical: 12 weeks
Protocols
Aronen & Regan
  • Noted a lack of regimented protocols for treatment of shoulder instabilities at the time
  • Looked at 20 male members of the Navy with acute primary anterior shoulder dislocations
  • Put subjects through a specific strengthening program emphasizing IR and shoulder adduction
  • After 3 years the subjects had a 75% success rate, that is, only 25% experienced re-injury
  • Re-injury occurred at a rate of 50-90% in non-surgical patients then, which is similar to current rates.
Wilk et al note the following 7 factors to consider when treating shoulder instability:
1) Onset of the pathology
2) Degree of instability
3) Frequency of dislocation
4) Direction of the instability
5) Concomitant pathologies
6) End range muscular control
7) Premorbid activity level

Conservative Protocol: (Dutton)
PHASE I
  • Goals
    • Reestablish non-painful ROM
    • Retard muscle atrophy
    • Avoid placing anterior capsule under stress (abduction and ER)
    • Shoulder hyperextension is contraindicated
Interventions:
  • ROM Exercises
    • Pendulums
    • Circumduction
    • Rope and Pulley: Flexion, AB to 90
    • L-Bar: Flex, AB, IR with arm in scapular plane, ER w/ arm in scap plane( progress arm to 90 AB as tolerated)
    • Posterior capsule stretching: sleeper
    • Upper extremity ergometer
  • Strengthening exercises
    • Isometrics: Flex, AB, Ext, IR (multi angles), ER (scapular plane)
    • Weight-shifts (closed chain exercises)

Criteria for progression to Phase II
Full ROM, minimal pain/tenderness, “Good” MMT of IR, ER, Flex, & AB

PHASE II
  • Goals
    • Regain and improve muscular strength
    • Normalize arthrokinematics
    • Improve neuromuscular control of shoulder complex
Interventions
  • Initiate isotonic strengthening
    • Flexion, AB to 90deg, IR, Sidelying ER to 45deg, Shoulder shrugs, Ext, Hor AD,
    • Supraspinatus, Push-ups
  • Initiate Eccentric (Theraband) exercises at 0deg AB
    • IR, ER
  • Normalize arthrokinematics of the shoulder complex
    • Continue joint mobilization
    • Patient education of mechanics and activity modification of activity/sport
  • Improve neuromuscular control of shoulder complex
    • Initiation of PNF
    • Rhythmic stabilization drills
    • Continue use of modalities (as needed): Ice, electrotherapy

Criteria for progression to Phase III
Full non-painful ROM, no palpable tenderness, continue progression of resistance exercises
Multiple protocols call for dynamic RTC strength of 80% of unaffected side prior to beginning practical overhead activities.

PHASE III
  • Goals
    • Improve strength
    • Improve neuromuscular control
    • Prepare patient/athlete for activity
Interventions
  • Continue use of modalities
  • Continue posterior capsule stretching
  • Continue isotonic strengthening (progressive resistance exercises)
  • Continue eccentric strengthening emphasize PNF
  • Initiate Isokinetics
    • Flex-Ext, AB-AD,IR-ER, Hor AB-AD
  • Initiate plyometric training
    • Theraband, Wall push-ups, Medicine ball, Boxes
  • Initiate Military Press
    • Precaution-avoid excessive stress on anterior capsule

Criteria for progression to Phase IV
  • Full ROM, No pain/tenderness, Satisfactory isokinetic test, Satisfactory clinical examination
Phase IV/Return to activity
  • Goals
    • Maintain optimal level of strength , power, and endurance
  • Continue all exercises as in phase III
  • Continue posterior capsule stretches
  • Continue modalities as needed
  • Follow-up: isokinetic test, Progress interval program, Maintenance of exercise program

EXERCISES
  • Isometric exercises.
    • Flexion, extension, internal rotation, external rotation, abduction, adduction.
  • Isotonic exercises
    • Flexion in supine, then standing, abduction (thumb up), external rotation while lying on opposite side, external rotation while prone, internal rotation with theraband, wall push-ups, biceps curl)
      • Perform with free weights only (No theraband - except IR #6).
      • Repetitions – 20-50 reps before adding/progressing in weight.
      • Start against gravity without weight; progress as tolerated to:
        • 2 oz. (dinner knife)
        • 4 oz. (tuna can)
        • 8 oz. (soup can)
        • 1 lb. weight
        • 2 lbs., 3 lbs., etc.
  • Goals:
    • Overhead athlete: 3-5 lbs x 50 reps.
    • General rehab candidate: 1-3 lbs x 30-50 reps.
    • Progress weight as tolerated – pain free
  • Scapular stabilization exercises
Recall the Reinold study(thanks Allison) found the following shoulder exercises most beneficial:
    • Supraspinatus: Full can
    • Infraspinatus/Teres Minor: SLER
    • Subscap: IR at 0
    • Serratus: Pushup plus
    • Lower trap: Prone full can
    • Middle trap: Prone Row
    • Upper trap: Shrug
    • Rhomboids/levator: Prone row

Surgical Intervention: (per Handoll H.H., et al’s systematic review)
  • Patient's <25 y.o. have a recurrence rate of up to 60-90% following conservative managment which is why surgical intervention may be a better option
  • Indicated for:
    • Patient's with recurrent unidirectional shoulder instability
    • Young, active people (particularly those that play high demand and contact sports)
Modalities:
  • Cryotherapy- used to reduce inflammation and pain and is usually done within acute stages of healing (15 mins 3-4 times per day)
  • Thermotherapy-used to reduce pain/discomfort and is usually done during the subacute and chronic phase
  • E-Stim- may help with pain reduction or muscle activation
  • Ultrasound- used to decrease joint stiffness, pain, to reduce any chronic edema if indicated, and promote healing
  • Taping- may help control the position of the scapula, this may help to normalize the muscle firing patterns
    • Basis for taping is to provide protection and support for a joint while permitting optimal functional improvement
    • The traction on the skin or the pressure of the tape provides cutaneous sensory cues, thus providing proprioceptive input to the CNS.
Research in regards to taping:
  • Cools A.M., et al.’s:
    • Purpose of their study was to examine the influence of tape application on scapular muscle’s (trapezius and serratus anterior) during a dynamic abduction and forward flexion movmemtn
    • 20 healthy male subjects with no current/past hx of shoulder issues with mean age 22.15 y.o.
    • Results: The lower trap seems best suited for postural and stabilizing functions in shldr and arm mvmts (had a predominance of type I fibres) whereas upper trap seems best suited for phasic act’s (had a higher frequency of type II fibres). Past research has also had the same conclusions.
    • The authors hypothesized that with taping, the upper trap would be inhibited while the lower trap would be facilitated (thus promoting normal scapular movements).
    • HOWEVER: The authors conclude there is not difference between mm activation with or without the tape and further research needs to be done as there were many constraints with this study.
  • Hsu Y.H., et al’s study:
    • Purpose: To investigate the effect of elastic taping on kinematics, mm activity and strength of the scapular region in baseball players w/shldr impingement.
    • 17 amateur baseball players (mean age 23 y.o) that had anterior or lateral shoulder impingement
    • Compared Kinesio taping to placebo taping (3 M Micropore tape) and each subject received both taping techniques for comparison
    • This study suggessts that the lower trap and serratus anterior are inhibited and there is over activation of the upper trap (w/patient’s that have shldr impingement). This is why taping is indicated for these folks.
    • Results: Kinesio taping improved lower trap activation only during the lower phase of scaption from 60-30 degrees
    • Note: Research has been conflicting and taping needs to be individualized to each patient.
    • ***Results suggested that Kinesio taping could be a useful therapeutic and prophylactic assistance both in the rehabilitation clinic and in the field.

Alternative/Adjunct treatment options:

external image standard%201.jpg
  • Yoga therapy discusses diet, lifestyle, and activity modification
    • Ayurvedic assessment and Ayurvedic based yoga recommendations for the condition: is based on the "vata, pita, kapha." I think this is similar to the "chi" where you are putting the bad energy into the light socket possibly.
    • Vitamins/minerals/herbs:- Vitamin C with bioflavonoids helps to reduce inflammation and repair connective tissue and collagen after injury.- Evening Primrose Oil contains gamm-linolenic acid (GLA) which is a building block for antiinflammatory chemicals in the body.- Vitamin A and vitamin E help to repair connective tissue and cells.- Bromelain can help reduce acute, painful inflammation following soft tissue injuries.
    • (http://www.yogatherapycenter.org/articles/Shoulder%20Dislocation%20%20-%20Mindy%20Lutz.pdf)
  • Home remedies:

References:

  • Cools A.M., Witvrouw E.E., Danneels L.A., Cambier D.C., Does taping influence electromyographic muscle activity in the scapular rotators in shoulders? (2002) Manual Therapy, 7(3),pp154-162.
  • Dumont, Guillaume D., Robert D. Russell, and William J. Robertson. "Anterior Shoulder Instability: A Review of Pathoanatomy, Diagnosis and Treatment." Modern Techniques in Shoulder Surgery (2011): 200-07. Print.
  • Dutton M. Orthopaedic Examination, Evaluation, and Intervention. 2nd ed. USA; MCGraw Hill Inc; 2008.
  • Gaunt, Bryce. Shaffer, Michael. The American Society of Shoulder and Elbow Therapistss’ Consensus Rehabilitation Guideline for Arthroscopic Anterior Capsulolabral Repair of the Shoulder. JOSPT. 2010. 40(3) 155-168.
  • Guerrero, Patrick. Busconi, Brian. Congenital Instability of the Shoulder Joint: Assessment and Treatment Options. Journal of Orthopedic and Sports Physical Therapy. 2009; 39(2) 124-134.
  • Handoll H.H., Almaiyah M.A., Rangan, A. Surgical versus non-surgical treatment for acute anterior shoulder dislocation. Cochrane Database Syst Rev. 2004;(1):CD004325.
  • Hayes, Kimberley, Mary Callanan, Judie Walton, Anastasios Paxinos, and George C. Murrell. "Shoulder Instability: Mangaement and Rehabilitation." Journal of Orthopaedic & Sports Physical Therapy 32.10 (2002): 497-502. Print.
  • Hsu y.H., Chen W.Y., Lin H.C., Wang W.T.J., Shih Y.F., The effects of taping on scapular kinematics and muscle performance in baseball players with shoulder impingement syndrome. (2009) Journal of Electromyography and Kinesiology, 19(6), pp. 1092-1099.
  • Johnson, Simon, and Michael Robinson. "Shoulder Instability in Patients with Joint Hyperlaxity." The Journal of Bone and Joint Surgery 92 (2010): 1545-557.
  • Reinold RM, Escamilla R, Wilk KF. Current Concepts in the Scientific and Clinical Rationale Behind Exercises for Glenohumeral and Scapulothoracic Musculature. JOSPT. 2009; 39(2): 105-117.
  • Wilk KE. “New Trends in the Treatment of the Overhead Athlete. 24th Annual Advances on the Knee and Shoulder. Hilton Head, SC. 24 May 2009.
  • Aronen JG, Regan K. Decreasing the Incidence of recurrence of first time anterior shoulder dislocations with rehabilitation. American Journal of Sports Medicine. 1984 Jul-Aug; 12(4) 283-291.
  • Wilk KE, Macrina LC, Reinold MM. Non-operative Rehabilitation for Traumatic and Atraumatic Glenohumeral Instability. North American Journal of Sports Physical Therapy. 2006 Feb 1(1), 16-31.