Wednesday, December 10, 2014

Healing of the tuberosities after reverse shoulder replacement for proximal humerus fracture

The four part proximal humerus fractures in the elderly are a challenging problem. Healing of the tuberosities after hemi-arthroplasty or reverse shoulder replacement is of great importance to the function of the shoulder. Studies have shown that non union of the tuberosities and subsequent absorption can lead to loss of motion after shoulder replacement. Although patients having undergone a reverse shoulder replacement after a four-part proximal humerus fracture experience greater relief of symptoms compared to those who receive hemi-arthroplasty, it is important to state that healing of the tuberosities is very important for improved range of motion and patient satisfaction. The following case is an elderly patient (age>70) who is active and independent. She had a fall and presented with a 4 part proximal humerus fracture. Open reduction and internal fixation has very high rates of failure and for this reason she was offered a reverse shoulder replacement.

Xrays before and after surgery are shown below

Postoperative X-ray demonstrates anatomic alignment of the greater tuberosity. The glenosphere was placed inferioly on the glenoid to avoid notching, polyethylene debris and loosening.

There are key steps in the setting of fracture that need to be considered in order to increase the chances of tuberosity healing.

(1) Stable fixation of the tuberosities using at least 7 sutures - non absorbable (#2 Fiberwire or equivalent). Please see configuration below. There has to be (a) tuberosity to tuberosity fixation (b) tuberosities to prosthesis fixation (c) lesser tuberosity to proximal humerus fixation and greater tuberosity to proximal humerus fixation

(2) Removal of cement proximally. Leave 1 cm of bone exposed at the proximal humerus, free of cement, to allow bone to bone contact of the tuberosities with the proximal humeru. Cement to bone contact may interfere with healing.

(3) Use of a press fit stem when possible to avoid thermal necrosis of the bone proximally from cement that interferes with healing. In addition, endosteal blood flow to fracture site is compromised with cementation

(4) Avoid usage of a high lateral offset glenosphere. Over-lateralization will lead to inability to bring the greater tuberosity around the proximal humerus. If you over-lateralize or over-lengthen the arm there will be not enough infraspinatus length to achieve bony contact of the greater to lesser tuberosity and the greater tuberosity will "sit" postero-laterally instead of laterally.

(5) Avoid over-tensioning of the deltoid and over-lengthening of the arm. Usually "sitting" the prosthesis at the medial calcar provides the right degree of tensioning of the deltoid. Instability is not of significant concern in the setting of a fracture as it is in setting of cuff tear arthropathy. As long as you can bring the tuberosities around the proximal aspect of the prosthesis to achieve bony contact the construct will be stable. Alternatively, another method to assess appropriate tensioning, during trialling, reduction of the construct should be done easily without significant traction force.

(1) Tuberosity to tuberosity fixation. At the bone-tendon junction of the greater and lesser tuberosity two traction non absorbable sutures are placed. Total of 4 sutures. These sutures are use as traction sutures and also for tuberosity to tuberosity fixation

(2) Tuberosities to proximal humerus fixation

(3) Tuberosities to prosthesis fixation

Below the final construct is demonstrated after placement of sutures and closure of the tuberosities around the prosthesis.

Sutures passed as described in the drawing above
With traction the tuberosities can easily come in contact between them and to the proximal humerus

Sutures are placed at the tendon bone junctions and not through the bone for better stability of the construct. The sutures will cut through the bone is placed through the bone of the tuberosities
Final construct after tying the knots

1 month after surgery x-ray shows healed tuberosities.

More tips are reported at the AAOS website by Pascal Boileau, MD at