Can the need for future surgery for acute traumatic anterior shoulder dislocation be predicted?
Abstract: Sachs RA, Lin D, Stone ML, Paxton E and Kuney M (2007): Can the need for future surgery for acute traumatic anterior shoulder dislocation be predicted? Journal of Bone and Joint Surgery 89(A): 1665-1674. (Abstract prepared by Margie Olds)

Background: Some surgeons have proposed immediate surgical stabilisation for those who are at high risk of recurrent shoulder instability. Sachs et al (2007) studied the factors which may predict recurrent instability in those suffering from recurrent shoulder instability following a primary injury, to determine if it is possible to predict the need for future surgery.

Methods: A prospective study which followed patients for five years. Participants were included if they had a first time traumatic anterior shoulder dislocation and reported to the emergency room. Patients were excluded if they had a history of previous dislocation, previous injury, or presented with atraumatic instability. The following variables were recorded; body type, hyperlaxity, age, sex, occupation, occupational use of the arm, other unstable joints, and a family history of unstable joints. The dislocation was quantified with regards to the degree of trauma, a score on a pain scale, method of reduction, duration of pain medication, time missed from work, and duration of sling usage. Sports activity was also quantified with regards to the number of sports hours per year. Phone calls were made to the participants every 6 months over a five year period.

Results: One hundred and thirty one participants completed the study. Twenty nine underwent surgery, leaving 102 participants to be followed over the five year period. Fifty two (40%) of the injuries were on the dominant side. Use of a sling was left to choice and 85 patients removed the sling after one week. Over the study period, 88 (67%) shoulders remained stable while 43 (43%) participants suffered from recurrent instability of the shoulder. Most of the surgical procedures were undertaken within two years of the initial injury. Gender did not make a difference to rate of recurrence.

For statistical purposes, patients were divided into two groups dependent upon their age. The younger groups (under the age of 40 years) comprised 90 patients, 51 of whom stayed stable within the follow-up period. Thirty-nine (43%) suffered from recurrent dislocation. In the older age group (greater than 40 years), 37 (90%) remained stable, while four experienced recurrent dislocation. Patients who eventually underwent surgery tended to have higher initial pain scores (p=0.01). Those who underwent surgery for rotator cuff lesions also reported a longer time for pain resolution after shoulder reduction (p=0.036). The total number of sporting hours was not predictive of recurrent dislocation. Subsequent instability was also more likely in those who performed work at or above chest level in their daily occupation. Multi-variate analysis indicated that an age of less than 25 years was the strongest indicator for predicting subsequent instability.

Conclusion: The need for immediate surgery is not indicated solely as a function of age, based upon unhappiness, future dislocation and disability.
Article Type: Report
Subject: Analgesics (Health aspects)
Analgesics (Research)
Surgery (Health aspects)
Shoulder joint (Dislocation)
Shoulder joint (Care and treatment)
Shoulder joint (Research)
Authors: Sachs, R.A.
Lin, D.
Stone, M.L.
Paxton, E.
Kuney, M.
Pub Date: 11/01/2010
Publication: Name: New Zealand Journal of Physiotherapy Publisher: New Zealand Society of Physiotherapists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2010 New Zealand Society of Physiotherapists ISSN: 0303-7193
Issue: Date: Nov, 2010 Source Volume: 38 Source Issue: 3
Topic: Event Code: 310 Science & research
Product: Product Code: 2833339 Analgesics & Antipyretics NEC; 8000410 Surgical Procedures NAICS Code: 325411 Medicinal and Botanical Manufacturing; 62 Health Care and Social Assistance SIC Code: 2833 Medicinals and botanicals; 2834 Pharmaceutical preparations
Geographic: Geographic Scope: New Zealand Geographic Code: 8NEWZ New Zealand
Accession Number: 263880356
Full Text: Commentary

There is much published literature regarding surgical vs. non-surgical treatment following primary dislocation. In a systematic review, Handoll (2005) documented statistically less re-dislocations in those who were treated surgically following a traumatic anterior dislocation (RR=0.25, 95% CI 0.14-0.44). In light of this, some authors have advocated early surgical intervention following acute dislocation in those under 25 years (Boone and Aciero, 2010).

Due to good outcomes from surgical intervention, it seems advantageous to immediately decide which patients would benefit from surgical intervention and which patient should be treated non-operatively. Identification of predisposing factors such as age (Hovelius et al, 2008), size of Bankart lesions (Rhee and Lim, 2007) or size of Hill Sachs lesions (Kralinger et al, 2002) may be one way that could aid in determining the patient's risk of re-dislocation.

Muscle activity around the unstable shoulder also remains in the spotlight. Alterations in electromyographic recordings of biceps brachii, supraspinatus, infraspinatus and subscapularis have been shown in unstable shoulders compared with controls (Myers et al, 2004). Additionally, there is some architectural evidence that subscapularis is responsible for stability on the apprehension position of 90[degrees] abduction and 90[degrees] external rotation. In contrast, Werner et al (2007) proposed that subscapularis may actually facilitate anterior-inferior dislocations in some positions depending upon a 'yet to be indentified' factor. These factors could include the size and position of the Bankart lesions and/or Hills Sachs lesion. Thus it may be that those who dislocate anteriorly should be discriminated from those that dislocate anterior-inferiorly.

Despite increased occurrence of recurrent shoulder instability in the younger patient, there is not sufficient evidence to support immediate surgical stabilisation in the acute setting. This study failed to show that body type, hyperlaxity, family history, degree of trauma, time missed from work, and duration of use of sling influenced the rate of recurrence. Other factors which may influence shoulder stability and episodes of recurrence are strength, stiffness and proprioception of the shoulder, location and size of pathological lesions (e.g. Bankart lesions), nerve palsy and direction of instability, as well as genetic make-up (collagen type). Future studies investigating other factors and the development of algorithms are necessary in order to accurately predict those that will not respond to non-operative treatment and require surgical intervention.

Margie Olds BPhty, PGDip, MSc(Hons)

Post-Graduate Clinical Co-ordinator

AUT University

REFERENCES

Boone JL and Aciero RA (2010): First-time anterior shoulder dislocations: has the standard changed? British Journal of Sports Medicine 44. 355-360.

Handoll HHG and Almaiyah MA (2003): Surgical versus non-surgical treatment for actue anterior shoulder dislocation. Cochrane Database of Systematic Reviews. 2007; (1).

Hovelius L, Olofsson A, Sandstrom B, Augustini BG, Krantz L, Fredin H, Tillander B, Skoglund U, Salomonsson B, Nowak J and Sennerby U (2008). Nonoperative treatment of primary anterior shoulder dislocation in patients forty years of age and younger. a prospective twenty-five-year follow-up. Journal of Bone & Joint Surgery 90A(5): 945-952.

Kralinger FS, Golser K, Wischatta R, Wambacher M and Sperner G. (2002): Predicting recurrence after primary anterior shoulder dislocation. American Journal of Sports Medicine 30: 116-120.

Myers JB, Ju Y, Hwang J, McMahon P and Lephart SM (2004): Reflexve muscle activation alterations in shoulders with anterior glenohumeral instability. American Journal of Sports Medicine 32: 1013-1021.

Werner CML, Favre P and Gerber C (2007): The role of subscapularis in preventing anterior glenohumeral subluxation in the abducted externally rotated position of the arm. Clinical Biomechanics 22: 495-501.
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