Symptomatic chronic instability of the elbow is a rare condition. Despite its rarity it is the most common chronic instability of the elbow. In this condition the forearm complex rotates externally in relation to the humerus, when the elbow is flexed. The radial head is usually posteriorly subluxated or dislocated and the patients complain that the elbow is unstable. The lateral ligament complex, radial head and coronoid process are important constraints to posterolateral rotatory instability, and their disruption is involved in the pathogenesis of this condition.
During clinical examination there might be positive active and passive apprehension tests, and examination under anaesthesia may more accurately indicate the problem. Surgical treatment is required, and reconstruction of the lateral collateral ligament complex is performed using tendon autograft or allograft.
In this case a palmaris longus autograft was used. The patient complained of "unstable" elbow during strenuous activities. He had a positive elbow apprehension test in the office and stress elbow xrays indicated "opening" of the radiocapitellar joint on the involved side (L) when compared to the uninvolved one (R). Please see below
Zooming on the lateral collateral ligament complex is beneficial as most of the time the LCL complex is disrupted from it humeral origin. Here we see the avulsed bony fragment. The MRI below confirms the diagnosis
The images below indicate the 'docking technique" for fixation of the palmar longus tendon allograft that was used in this case. One of the technical difficulties of this surgery is the "scarring" of the remaining LCL complex on the capsule and annular ligament which requires cautious dissection in order to separate the ligament from the surrounding structures. Below the anatomy is outlined and a schematic drawing of the point of isometry on the capitellum. The insertion site of the graft on the ulna is indicated as well. The supinator crest needs to be palpated or exposed to identify the insertion area of the graft on the ulna
The xray above indicates the insertion site of the graft on the ulna. The distance between the two drill holes on the ulna is 1-3 cm.
This patient at 8 weeks had full ROM and no pain, no apprehension or feelings of instability of the elbow.
