although typically thought to occur in older individuals , a hooked acromion causing shoulder impingement symptoms in younger populations is less recognized .
this report illustrates a case of type iii acromial impingement in a younger athlete and the importance of early imaging in refining diagnosis .
a 31-year - old right - hand dominant cross - fit personal trainer presented to an outpatient clinic complaining of left shoulder pain worsening over a 2-year period .
the pain had become intermittently worse over the last 6 weeks , and was particularly flared the day following handstand push - ups and kipping .
pain was reportedly worsened by shoulder abduction beyond 90 , bicep hammer curls and eccentric bench press .
the patient perceived the left shoulder to be more elevated than the right at rest , and he had begun to note joint crepitus on circumduction . the pain was focal to the anterior aspect of the deltoid and upper biceps region with an occasional pulling sensation in the distolateral biceps .
the patient was perplexed as to why the left shoulder was painful when he was right - handed .
he described a 38/10 baseline daily pain , increasing to 10/10 with bicep curls and eccentric bench press .
he pain with activities of daily living such as removing his shirt , lifting his 2-year - old child , and he was unable to sleep on his left side . despite the pain
he took no medications , had no reported drug allergies or prior reactions to anesthesia .
he was a non - smoker , and had been engaged in professional power lifting since 2008 .
cervical spine ranges of motion were pain free and the spurling 's test with extension was negative .
a painful arc was present upon left shoulder abduction with hitching a reported pain at 90. there was , however , no palpable or audible crepitus on left shoulder circumduction .
however , there was a focal area of tenderness upon palpation 3 cm proximal to the left lateral epicondyle .
mill 's & cozen 's tests were negative , and resisted muscle testing of the common extensor origin and extensor carpi radialis brevis was unremarkable .
the left proximal biceps tendon and medial aspect of the left acromial - clavicular joint ( acj ) was focally tender on palpation .
the initial diagnostic impression was of chronic left shoulder impingement ( query subacromial bursal effusion , early rotator cuff ( rc ) tear , down - sloped acromion ) , and mild acj osteoarthritis .
although the physical examination was generally unremarkable , the history was indicative of some mild left extensor origin biceps tendonopathy .
the patient was referred for a non - contrast magnetic resonance imaging ( mri ) of the left shoulder .
the study reported high signal intensity within the belly of the supraspinatus muscle belly and tendon associated with a type iii downward - sloping acromion , which was interpreted to be causing  a degree of impingement .
there was also a small amount of fluid in the subacromial space raising the possibility of associated subacromial bursitis ( fig .
the report of imaging findings and prognostic discussion convinced the patient of the importance to alter the intensity of his upper body training activities . by simply avoiding repetitive overhead activities and modifying the intensity of his upper body exercise program , impingement symptoms abated considerably over a period of several weeks .
as the patient was responding to conservative management and there was no evidence of rc tear on imaging , surgical referral was postponed .
there are several functional and potentially reversible causes of shoulder impingement syndrome . however , identifying the presence of bony impingement of the subacromial space may aid in a better understanding of predispositions to rc pathology .
the original bigliani acromial morphology classification of type 1-flat , type ii - curved and type iii - hooked has more recently in updated by vanarthos and monu , to include a type iv - convex morphology ( fig .
some studies have identified a significant association between type iii acromial morphology and full thickness rc tears . although type iii acromion ( t3a ) may be rare in asymptomatic young athletes , the incidence of in a general population of both young and older individuals is still not completely understood . typically , older patients are noted to have a high incidence of t2a and t3a ( 93% of those over 70 ) and both of full and partial - thickness rc tears were more commonly with these morphologies than type i .
neer concluded that 95% of rc tears are caused by mechanical impingement , associating rc tears with extremely hooked ( > 43 ) anterior acromial slope .
other studies have looked at the lateral extension and angulation of the acromial slope also being important in diagnosing and managing impingement pathologies .
although thought to be associated with older populations , t2 down - sloped and t3 hooked acromial impingement may occur in younger populations such as overhead athletes .
impingement may be manifested by pain with overhead activities , shoulder weakness and decreased range of motion .
early shoulder x - rays including the outlet  y view to define acromial morphology , or mri imaging may help to refine diagnosis , prevent inappropriate therapies , understand prognosis and expedite more effective management strategies .
appropriate surgical referrals are patients with subacromial impingement syndrome refractory to 36 months of appropriate conservative treatment .
 down - sloped or hooked acromion morphologies may cause bony encroachment on the soft tissues of the subacromial space , predisposing to shoulder impingement syndrome . of the latter , a hooked or type iii acromion ( t3a ) has also been linked to rotator cuff ( rc ) pathology . 
 however , as bony acromial impingement is typically thought to occur over the age of 40 , its occurrence in younger shoulder athletes presenting with shoulder pain , impingement and rc pathology may be overlooked . 
 this case serves to illustrate the occurrence of t3a in a younger shoulder athlete , and the importance of early imaging in achieving diagnostic accuracy . 
 appropriate surgical referrals are patients with subacromial impingement syndrome refractory to 36 months of appropriate conservative treatment . 
 surgery may be particularly beneficial in patients with a t3a . 
INTRODUCTION
CASE REPORT
DISCUSSION