The damaged component
Case 110
【Discussion】Physis is a growth plate of new bone formation which exists at the joint and at the connection of the tendon and the ligament. Epiphysis is the bony end and the normal bony outgrowth part of a long bone, while apophysis is the normal bony outgrowth at a site of tendon or ligament. Both epiphysis and apophysis eventually fuse to metaphysis before age of twenty (1, 2). Our patient aged 11 had an opening physis and ulnar epicondylar apophysis which attached to flexor tendons and protected by ulnar collateral ligament.
In children, repetitive and extensive valgus motion of a pitcher throwing ball gives stress to physis and apophysis rather than ulnar (medial) collateral ligament since physis is open. As a result, it causes avulsion or detachment of physis and injury of apophysis. In our case, MRI showed detachment of physis and bone marrow edema of apophysis (Figs 1, 2), corresponding to little league elbow (3, 4).
Meanwhile, in adults, vulgar motion of pitcher in major league most causes the damage to ulnar collateral ligament rather than physis and apophysis because physis is closed and apophysis fuses to metaphysis (1, 2). Ulnar collateral ligament composes of three bundles: anterior bundle, intermediate bundle and posterior bundle. Anterior bundle is the largest and susceptible to stress damage. As other injuries, flexor tendinitis, valgus extension overload, olecranon stress fracture and ulnar neuritis are listed (5-7). The wrist flexors (pronator teres, flexor carpi radialis, flexor carpi ulnaris) which attached to medial epicondyle of humerus, work contraction in a golf swing and baseball pitch. The overuse of flexors causes flexor tendinitis. Valgus extension overload indicates that in throwing, olecranon of ulna and humerus are twisted and forced each other, and the cartilage on the olecranon is worn away, leading to formation of bone spur or osteophytes. Olecranon stress fracture occurs when flexor muscles are fatigued and unable to absorb overload, implying a tiny crack in the olecranon. When throwing, ulnar nerve is stretched repeatedly, leading to irritation of the nerve. MRI with fat suppression T2 weighted imaging contributes to identify and differentiate the cause of the elbow pain (8-10).
When throwing stress tears ulnar collateral ligament which is ineffective using medicines, Tommy Jones operation is performed which stabilize the ulnar side of elbow in taking place of ulnar collateral ligaments (5-7). Because it is difficult to suture the damaged ulnar collateral ligament, Tommy Jones operation which is developed by a team doctor of Dodgers, reconstructs the damaged ulnar collateral ligament using tendon from forearm and/or hamstring. The operation is called “Figure-of-eight technique” in other word from a macroscopic picture (5-7).
Golf elbow occurs on the same damaged site as baseball elbow: humerus medial epicondyle. Flexor muscle tendons attached to the humerus medial epicondyle is damaged. Meanwhile, tennis elbow occurs on the humerus lateral epicondyle attached extensor muscles (extensor carpi radialis brevis and longus) which work in repetitive grasping and gripping. In short, micro-tearing of flexor muscles causes golf elbow and micro-tearing of extensor muscles causes tennis elbow.
【Summary】
We present an eleven year-old boy, suffering from his right persistent medial elbow pain. He was a right-handed pitcher of the little league baseball team. MRI showed detachment of physis and bone marrow edema of apophysis, corresponding to little league elbow. It is borne in mind that physis exists at the joint and at the connection of the tendon and the ligament. Apophysis is the normal bony outgrowth at a site of tendon or ligament. In children, repetitive and extensive valgus motion of a pitcher throwing causes avulsion or detachment of physis and injury of apophysis. Meanwhile, in adults, vulgar motion of pitcher causes the damage to ulnar collateral ligament rather than physis and apophysis because apophysis fuses to metaphysis. As other injuries, flexor tendinitis, valgus extension overload (olecranon spur), olecranon stress fracture and ulnar neuritis are listed. Tommy Jones reconstruction operation using tendon from forearm and/or hamstring, is performed for the damaged ulnar collateral ligament because it is difficult to suture it. Golf elbow occurs on the same humerus medial epicondyle as baseball elbow. Meanwhile, tennis elbow occurs on the humerus lateral epicondyle after repetitive grasping and gripping. In short, micro-tearing of flexor muscles causes golf elbow and micro-tearing of extensor muscles causes tennis elbow.
【References】
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