Background: Partial resection of the posteromedial aspect of the
olecranon in the treatment of valgus extension impingement osteophytosis is a
well-described technique. It has been hypothesized that removal of the normal
olecranon process, beyond the osteophytic margin, increases the strain in the
anterior bundle of the medial collateral ligament.
Methods: We used an electromagnetic tracking device to investigate
the strain in the anterior bundle of the medial collateral ligament as a
function of increasing applied torque and posteromedial resections of the
olecranon in seven cadaveric elbows. Applied torques under valgus stress
consisted of hand weight, hand weight plus 1.75 Nm, and hand weight plus 3.5
Nm. Resections were conducted in sequential 3-mm increments, from 0 to 9 mm.
We measured changes in the length of the anterior and posterior bands of the
anterior bundle of the medial collateral ligament with strain gauges. The
strains of the two bands were averaged, and the average was reported.
Results: The strain in the anterior bundle of the medial collateral
ligament was found to increase with increasing flexion angle, valgus torque,
and olecranon resection beyond 3 mm. In two elbows, the anterior bundle of the
medial collateral ligament ruptured during testing following the 9-mm
resection. There was a significant difference between the strain following the
6-mm resection and that following the 3-mm resection at 110° of flexion
with 3.5 Nm of added torque (p = 0.004).
Conclusions: In this in vitro cadaver study, an increase in flexion
angle, an increase in valgus torque, and resection of =6 mm led to an
increase in strain in the anterior bundle of the medial collateral ligament.
The non-uniform change in strain related to 3 mm of resection suggests that
resections of the posteromedial aspect of the olecranon of >3 mm may
jeopardize the function of the anterior bundle.
Clinical Relevance: Resection of the olecranon beyond the
posteromedial osteophytic margin increases the strain in the anterior bundle
of the medial collateral ligament, with the potential for a consequent
ligament rupture. We advise resection of the osteophytes only.