Correlation of Antero Inferior Glenoid Bone Loss with Number of Dislocations and Mode of Injury-Dr. Aravindh Palaniswamy

Correlation of Antero Inferior Glenoid Bone Loss with Number of Dislocations and Mode of Injury-Dr. Aravindh Palaniswamy

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  Correlation of Antero-inferiorGlenoid Bone Loss with Number of Dislocations and Mode of Injury Aravindh Palaniswamy, MS1 , Hira Lal Nag, MS1 , Dhanasekaraprabu, MS1 , Deep N Srivastava, MD2 Department of Orthopaedics1 & Radiodiagnosis2, All India Institute of Medical Sciences, New Delhi, India
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  Introduction • Recurrentshoulder dislocation is a common cause of morbidity among young adults with an annual incidence of 0.084% & 1.7%(1) . • Natural history of the unstable shoulder evolves towards progressive glenoid bone loss. • Incidence as high as 86%(2) in recurrent instability. 1.Hovelius L. Incidence of shoulder dislocation in Sweden. Clin Orthop Relat Res 982:127-131. 2.Griffith JF, Antonio GE, Yung PSH, Wong EMC, Yu AB, Ahuja AT, et al. Prevalence, Pattern, and Spectrum of Glenoid Bone Loss in Anterior Shoulder Dislocation: CT Analysis of 218 Patients. Am. J. Roentgenol. 2008 May;190(5):1247–54.
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  Introduction • Theintegrity of the osseous architecture of the glenoid has been highlighted as one of the most important factors related to the success/failure of surgical repair(3,4). 3.Randelli P, Ragone V, Carminati S, Cabitza P. Risk factors for recurrence after Bankart repair a systematic review. Knee Surg. Sports Traumatol.Arthrosc. 2012 Jul 27;20(11):2129–38. 4.ITOI E, LEE S-B, BERGLUND LJ, BERGE LL, AN K-N. The Effect of a Glenoid Defect on Anteroinferior Stability of the Shoulder After Bankart Repair: A Cadaveric Study*. J. Bone Jt. Surg. 2000;82(1):35–46.
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  Introduction • Three-dimensionalreformatted computed tomography scan images provides most accurate assessment of bone deficiency(6). 6.MOON Shoulder Group, Bishop JY, Jones GL, Rerko MA, Donaldson C. 3-D CT is the Most Reliable Imaging Modality When Quantifying Glenoid Bone Loss. Clin.Orthop.Relat. Res. 2012 Sep 21;471(4):1251–6.
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  Introduction • Glenoidbone loss – multifactorial origin(5) – Increasing number of dislocations – Trauma at first dislocation – Age of first dislocation • Considered as strong predictors for the presence and the percentage of glenoid bone defect 5.Provencher CMT. Recurrent Shoulder Instability: Current Concepts for Evaluation and Management of Glenoid Bone Loss. J. Bone Jt. Surg. Am. 2010 Dec 1;92(Supplement_2):133.
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  Study Rationale –Pre-Op CT ? • Is it Specific findings in the history and the physical examination provide important clues to the presence of glenoid bone loss. • Is it critical to evaluate all patients with recurrent shoulder instability for the presence of osseous injuries to the glenoid.
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  Objectives • Tocorrelate the percentage of glenoid bone loss with ‘number of dislocations’. • To asses the influence of ‘mode of injury’ on glenoid bone loss in patients with recurrent anterior dislocation of shoulder.
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  Methodology • Typeof study – Observational Study • Sample size – 20 patients • Approved by Institutional ethics committee • Informed consent obtained
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  Methodology Inclusion criteria • Patients with recurrent anterior shoulder dislocation • Unilateral involvement • Age 15 to 45 years Exclusion criteria • Habitual dislocation • H/o previous surgery for shoulder dislocation • Any associated congenital anomaly
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  Patient Evaluation •A detailed clinical history – Mode of injury (Trauma/Sports Injury) which led to dislocation – Frequency of dislocations were noted • Physical examination for anterior apprehension & s/o laxity
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  Patient Evaluation •CT Protocol & Image Analysis – Simultaneous CT examination of both shoulders were acquired in MDCT scanners (Somatom sensation, Siemens, Erlanger, Germany) with a volume data acquisition of 0.6 X 40, slice thickness of 0.6 mm with the scanning plane extending from the acromion to just below glenoid.
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  Patient Evaluation –3D volume rendered images were reconstructed – ‘En face view of glenoid’ obtained after subtracting humeral head.
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  Patient Evaluation •Calculation of glenoid index – On en face view of glenoid of 3 D volume rendered image with use of built in software tools of Siemens Syngo. – A line drawn along the long axis of glenoid & second glenoid line drawn perpendicular to the long axis of glenoid at the inferior glenoid from the posterior margin to the anterior margin
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  Patient Evaluation •Calculation of glenoid bone loss – Width of the glenoid (glenoid index) in millimetres calculated on affected(d) and normal shoulder(D) – Based on the glenoid linear defect method percentage of bone loss was calculated using the formula [ (D-d)/D] x 100 • Statistical analysis performed with statistical software (SPSS version 19)
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  Results • Meanage 26.5 ±5.9 years (range 20 to 42 years) • Male: Female ratio 19:1 • 70% of patients (n=14) had dislocation of right shoulder • Glenoid bone loss present in 90% (n=18) patients • 10 patients had ≤ 10% glenoid bone loss, 5 patients between 10 and 20%, 2 between 20 and 30% while 1 patient had >30% bone loss • Sports injury was the predominant mode of injury in 55% of patients (n=11) while trauma was implicated in rest of the patients • No. of recurrent dislocations varied from 2 to 20 with a mean of 7.7 (± 5.7)
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  No. of dislocationsand glenoid bone loss (%) in individual study patients 35 30 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Study patients NO. OF DISLOCATIONS GLENOID BONE LOSS (%)
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  Correlation between glenoidbone loss and no. of dislocations Spearman's rho = 0.358 p=0.12
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  Glenoid bone lossin patients with sports injury and trauma 14 12 10 8 6 4 2 0 7.2 13.7 Sports Injury Trauma Glenoid bone loss (%) Mode of Injury (p=0.053) 7.2 (± 9.1) 13.7 (± 7.4)
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  Discussion • Anteroinferiorglenoid bone loss present in 90% of patients. • Frequency of dislocations less important in determining bone loss(p=0.12) • One patient with 20 episodes of dislocations had 0% of bone loss with glenoid width measuring of 25mm and another patient with only 5 episodes of dislocation had 24.6% of bone loss with a glenoid width of 17.6mm • Initial mode of injury may appear to influence the defect (p=0.053).
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  Discussion • Milanoet al (7) – Initial mode of injury or the severity of trauma of the first few episodes and age at first dislocation are significant predictors of glenoid bone loss in anterior shoulder instability. – Even though frequency of dislocations correlated with percentage of bone loss in their study, it was largely influenced by other confounding factors such as ‘force sustained in the initial trauma’, the duration of the disease .
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  Discussion • Griffithet al(2) – Clear relationship between traumatic mode of injury in the initial episode of dislocation & percentage of bony bankart. – Inverse Exponential relationship was found between the degree of anterior flattening and the number of dislocations. – First few dislocations had a greater effect on the percentage of bone loss.
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  Discussion • YongGirl Rhee et al(8) – Age, activity, frequency and interval of dislocation have close relationships with the redislocation rates. – But presence of bony Bankart lesions are unrelated to the redislocation rates. – It is possible that type of Bankart lesion & severity of bony Bankart lesions are determined at first dislocation.
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  Conclusion • Frequencyof dislocations appeared to less important in determining the amount of glenoid bone loss • Initial mode of injury causing the first episode of anterior shoulder dislocation may appear to influence the defect Study Limitation • Small sample size
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  Clinical Relevance Adequateimaging with 3D CT should be included in routine preoperative evaluation in patients with recurrent anterior shoulder instability to avoid any unpleasant surprises intra operatively
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  Thank you