Recent studies have suggested that tenotomy and repair of the subscapularis
tendon carried out for anterior approaches to the shoulder can be followed by
failure of the tendon repair and by changes resulting in permanent loss of
subscapularis function. We hypothesized that release of the subscapularis with
use of a superficial osteotomy of the lesser tuberosity followed by repair of
the two opposing bone surfaces would lead to consistent bone-to-bone healing,
which would be possible to monitor radiographically, and would lead to
satisfactory clinical and structural outcomes.
Thirty-nine shoulders in thirty-six consecutive patients who, at an average
age of fifty-seven years, had undergone total shoulder replacement through an
anterior approach involving an osteotomy of the lesser tuberosity were
evaluated at an average of thirty-nine months. Assessment included a
standardized interview and physical examination, scoring according to the
system described by Constant and Murley, and imaging with conventional
radiography and computed tomography to assess healing of the osteotomy site
and changes in the subscapularis.
The osteotomized tuberosity fragment healed in an anatomical position in
all shoulders, and no cuff tendon ruptures were observed. At the time of
follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a
belly-press test had a negative result and twenty-seven (75%) of thirty-six
shoulders evaluated with a lift-off test had an unequivocally normal result.
Fatty infiltration of the subscapularis muscle increased after the operation
(p < 0.0001) and was at least stage two in eleven (32%) of thirty-four
shoulders. The fatty infiltration had progressed by one stage in eight (24%)
of the thirty-four shoulders, by two stages in five shoulders (15%), and by
three stages in two shoulders (6%).
Osteotomy of the lesser tuberosity provides an easy anterior approach for
total shoulder replacement and is followed by consistent bone-to-bone healing,
which can be monitored, and good subscapularis function. In the presence of
documented anatomical healing of the osteotomy site, postoperative fatty
infiltration of the subscapularis muscle remains unexplained and needs to be
investigated further as it is associated with a poorer clinical outcome.