The Journal of Bone and Joint Surgery

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A Missed Diagnosis¹
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The patient underwent open reduction and internal fixation of the posterior fracture-dislocation of the left shoulder. Through an anterior deltopectoral approach that preserved the deltoid and pectoralis major muscles, the interval between the superior border of the subscapularis tendon and the anterior margin of the supraspinatus tendon was developed to allow entry into the joint. It was not necessary to release any of the rotator cuff tendons. The humeral head was found to be dislocated posteriorly, with some capsular attachments to its posterior and inferior aspects. The head was reduced into the glenoid with use of a combination of external pressure over the posterior aspect of the joint, where the head was palpable, and intra-articular leverage with a long Darrach retractor. It then was realigned with the proximal aspect of the humerus and fixed with two threaded Steinmann pins, which were passed percutaneously in a lateral-to-medial direction to engage the subchondral bone of the humeral head (Fig. 3). Percutaneous Steinmann pins were chosen for fixation because they offered a simple method of stabilization and because their subsequent removal would avoid the possible problem of secondary impingement. The left upper limb was immobilized in a type of modified shoulder-spica cast (an above-the-elbow cast connected to an abdominal cast) with the shoulder in neutral rotation and 15° of abduction.

The patient wore the cast for four weeks and then wore a sling for an additional four weeks. During the period of immobilization in the sling, the patient was instructed to use the left arm for gentle activities of daily living, such as dressing and eating. The Steinmann pins were removed eight weeks after the operation. An intensive program of rehabilitation was started at the time of removal of the cast, and strengthening exercises were added at twelve weeks postoperatively.

Fig. 3. Postoperative anteroposterior radiograph showing reduction of the fracture and stabilization with two threaded Steinmann pins.

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Discussion

Displaced fracture of the anatomical neck with dislocation of the humeral head is a rare injury. Jakob et al. reported four such injuries in a series of 730 proximal humeral fractures². The rarity of this injury may cause the diagnosis to be delayed or missed. However, as with posterior dislocation of the glenohumeral joint without fracture, a frequent cause of misdiagnosis is the failure to obtain adequate radiographs. The critical element in the assessment of any injured shoulder is the standard trauma series, which includes anteroposterior, axillary lateral, and scapular lateral radiographs. If the diagnosis cannot be confirmed with these radiographs, then computerized tomography should be performed.

References

1. Kaar TK, Wirth MA, Rockwood CA Jr. Missed posterior fracture-dislocation of the humeral head. A case report with a fifteen-year follow-up after delayed open reduction and internal fixation. J. Bone Joint Surg Am. 1999;81:708-10.
2. Jakob RP, Kristiansen T, Mayo K, Ganz R, Müller ME.Classification and aspects of treatment of fractures of the proximal humerus. In: Bateman JE, Welsh PR, editors. Surgery of the shoulder. Philadelphia: B.C. Decker; 1984. p 330-43.