To date, no studies have looked at the relationship of preoperative and postoperative MP pinch position and passive MP hyperextension in an arthritic patient population. Other research has found that dynamic thumb MP pinch position is independent of passive MP hyperextension in a healthy non-arthritic population (thumbs with passive MP hyperextension on exam did not pinch in a position of MP hyperextension), but no such investigation has been performed in an arthritic population pre and postoperatively. It is also undetermined which of these parameters (dynamic pinch or passive MP hyperextension) has a larger correlation to postoperative outcomes following basilar joint arthroplasty, and which parameter should be considered when determining whether or not to surgically stabilize the MP joint at the time of CMC arthroplasty.~The specific aim of this study is to compare the preoperative and postoperative changes in dynamic and passive range of motion of the thumb MP joint in patients undergoing CMC basilar joint reconstruction without concomitant MP joint stabilization.~Secondary aims of this study will be to compare postoperative pinch and grasp strength, radiographic subsidence and longitudinal collapse, in addition to postoperative patient reported outcomes in patients with good dynamic MP control (<5 degrees) vs poor dynamic control (>5degrees)~The hypothesis is that dynamic thumb MP pinch position will not change compared with its preoperative status. Investigators also hypothesize that patients with better dynamic pinch position postoperatively will have better pinch strength and better functional outcomes than patients with poor dynamic pinch position.
This is the second phase of a clinical study to assess MP hyperextension in CMC arthritis. In the first phase, submitted for publication, the investigators demonstrated that there is poor correlation between dynamic control of the MP joint and the amount of passive hyperextension preoperatively in a sample of patients with CMC arthritis.