The Effect of Derotational Humeral Osteotomy On Global Shoulder Function in Brachial Plexus Birth Palsy

Author(s): Waters PM, Bae DS

Source: Journal Bone Joint Surg 88A: 1035-1042, 2006.

Summary:

This study is a retrospective review of 27 patients who were evaluated at a minimum of two-year follow up after humeral derotational osteotomy for dysfunction following obstetrical brachial plexus birth palsy.  The indications included patients with persistent internal rotation contractures and external rotation weakness despite prior soft tissue procedures and/or advanced joint deformity.  The procedure involved a delto-pectoral approach followed by a transverse osteotomy just superior to the deltoid insertion.  Osteotomy position was intraoperatively assessed to avoid over correction. The humerus was stabilized with and patients were immobilized in either a spica cast or a sling and swathe depending on the age of the patient.  Immobilization was typically discontinued after 4 to 6 weeks, following radiographic confirmation of osseous healing.  In patients with internal rotation and abduction contractures of the shoulder with external rotation weakness, a combination of external rotation and varus producing osteotomies were performed to allow for an improved position of the affected limb.  These patients often exhibited preoperative compensatory scapulothoracic motion in order to adduct the arm toward the side of the body resulting in elevation of the superior medial border of the scapula known as the Putti sign.  In these patients, after derotation was completed, a varus-producing medial closing wedge osteotomy was performed correcting for the shoulder abduction contracture.

Over an 8-year period between 1996 to 2004, 43 patients underwent a derotational humeral osteotomy and 27 patients were ultimately reported on who were followed for a minimum of 2 years (average, 3.7 years).  The mean patient age at the time of surgery was 7.6 years (range, 2.3 to 17 years).  Only 6 patients were operated on prior to the age of 6 years.  The mean rotational correction achieved during derotational humeral osteotomy was 64? (range, -40? to 90?).  For the 6 patients who underwent additional angular correction, a mean of 20? (range, 15? to 25?) of varus alignment was introduced to the longitudinal axis of the humerus.  All patients had successful healing of the osteotomy site with no nonunions.  All patients demonstrated improvements in global shoulder function, as evidenced by improved aggregate Mallet classification scores.  Radiographically, 27 of  the 28 patients undergoing derotational humeral osteotomy had a Type III glenoid deformity or worse with significant posterior humeral head subluxation and increased glenoid retroversion. Ten out of 27 patients had pseudoglenoid formation on MRI or CT and 7 had posterior glenohumeral dislocations.  Six of the 27 patients underwent a total of 8 additional surgical procedures following derotational humeral osteotomy.  These included scar revision, revision derotational osteotomy for incomplete correction, a latissimus dorsi teres major tendon transfer.  One patient sustained a humeral diaphyseal fracture below the previous plate during sports participation.  No patient underwent elective plate removal.

More aggressive extra-articular soft-tissue rebalancing and tendon transfers  (including that of latissimus and teres major combined with subscapularis release) may halt the progression of glenohumeral deformity and improve overall function in patients with obstetrical brachial plexus palsies and imbalance about the shoulder girdle.  However, these procedures have not been shown to substantially correct glenohumeral joint deformity.  In the setting of a patient with more advanced stage and severe dysplasia, especially pseudoglenoid and/or a flat humeral head, a soft-tissue reconstruction will not provide any functional benefit and some authors have suggested that such intervention may result in iatrogenic anterior glenohumeral instability.  The derotational humeral osteotomy described here does not improve overall glenohumeral motion, but rather improves upper extremity function by re-orienting the arc of shoulder rotation to a more functional range.  However, as expected an external rotational osteotomy provides no improvement in joint morphology.  A subset of the patients provided in this study included those with limitations of both external rotation and shoulder adduction. These patients underwent a combined external rotation and varus-producing osteotomy which ultimately  improved shoulder and arm position.  This eliminated the superior prominence of the medial border of the scapula indicating a notable correction.

Brachial, Plexus, Palsy, Shoulder, Derotational, Osteotomy

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