Corrective osteotomy for surgical neck proximal humerus varus malunion

The following case is a patient in her 40s who presented with a non displaced fracture of the proximal humerus. Serial radiographs at 2 and 4 weeks demonstrated varus collapse and malunion of the proximal humerus. Corrective osteotomy was performed in the operating room and application of a proximal humerus locking plate. We prefer to use the minimum length of humeral head screws necessary for fixation to avoid penetration of the articular surface, AVN and post-traumatic arthritis.

We elected to correct the deformity due to the young age and high level of activity of the patient. Two-part fractures of the surgical neck may heal in varus and anterior angulation. The humeral shaft displaces anteromedially because of the pull of the pectoralis major, and the proximal fragment is abducted by the rotator cuff. If the deformity is great enough, loss of forward flexion and abduction may be significant. 

Fracture well aligned at presentation

Two weeks after sling immobilization there is "acceptable" varus malalignment

Grashey view of the shoulder at 4 weeks after injury. There is severe angulation (45 degrees or more) of the humeral head with partial union

Proximal humerus osteotomy and fixation using a 3.5mm locking plate

Intra-operative AP view

Intra-operative axillary view

Currently, there is no universally accepted classification of proximal humeral malunions. Generally rotational malalignment of the articular segment by more than 45 degrees in the coronal, sagittal, or axial plane is considered severe deformity by most orthopaedic surgeons.

In this case, after the osteotomy the reduction was maintained after pinning the humeral head with a heavy Steinman pin from the lateral to medial direction and rotating the fragment with the aid of the heavy pin to correct the varus deformity as shown in the picture below.

From AO Foundation

There is little in the literature regarding the treatment of varus malunions of two-part surgical neck fractures of the proximal humerus. In varus deformities, the subacromial space is decreased as the greater tuberosity becomes closer to the coracoacromial arch. The lever arm of the supraspinatus tendon and the sliding surface of the humeral head and the glenoid are likewise decreased. These anatomical changes can cause impairment of active forward flexion and abduction and pain from impingement. Such functional limitations may be unacceptable to young patients or active older patients. Some investigators recommend release of soft tissue contractures and removal of bony prominences for less severe deformities.