Variable Immobilization Protocol for Arthroplasty of the Carpometacarpal Joint of the Thumb

Thumb CMC OA is common, with radiographic prevalence ranging from 7% to 35% in the literature, with symptomatic OA affecting 2% to 6% of the population. There is predilection for involvement of the non-dominant hand, and thumb CMC OA is the leading cause of hand pain due to degenerative changes. Gender-specific differences in thumb CMC OA prevalence have also been described in the literature. Retrospective review of 615 patients revealed a 6-fold higher prevalence of thumb basilar joint OA for females in nearly every age group, noting the presence of radiographic OA at younger ages in females, and quicker progression to end-stage degenerative changes.

While conservative treatment, such as injections, therapy, splinting, and pharmacotherapy, may palliate symptoms, operative intervention is recommended if symptoms are persistent. Trapeziectomy with or without suspensionplasty is most commonly performed for advanced osteoarthritis, and studies have shown that trapeziectomy with ligament reconstruction and tendon interposition (LRTI) is the most frequently performed procedure. Because of the extensive nature of this surgery with dissection and removal of the trapezium as a common central procedure, immobilization of the thumb and wrist has been a standard part of postoperative protocols to improve postoperative pain, function, and aid with return to daily activities.

Across many studies of operative technique and post-surgical care, there is no high-level evidence on the optimal duration of postoperative immobilization. With no consensus on the duration during which patients should restrict range of motion after thumb CMC joint surgery, there is a gap in knowledge on this topic. Immobilization following surgery is critical for wound healing, pain control, and aid with activities of daily living in the early recovery period, though the duration of this must be weighed against the negative impacts of immobilization, such as stiffness, contracture, and delay in return to full function. The information gained in this study may allow hand surgeons to use an evidence-based postoperative rehabilitation protocol. Thus, our goal is to compare varying durations of postoperative immobilization after thumb CMC arthroplasty in a randomized trial design.

In this study, we will prospectively evaluate varied duration of postoperative immobilization in patients older than 40 years, undergoing base of thumb arthroplasty at an academic, tertiary referral center. Patients will be randomized to either 2 or 6 weeks of immediate postoperative immobilization in a plaster thumb spica splint or cast. Functional outcome measures, including quickDASH (Disabilities of Arm, Shoulder, and Hand), PROMIS UE (Patient Reported Outcome Measures Information System Upper Extremity) form, and VAS (Visual Analog Scale) pain scale will be captured at short-term, intermediate-term, and final follow-up periods. Additionally, exploratory objective metrics, such as strength, range of motion (ROM), return to work, and occupational therapy (OT) utilization will be monitored at all time periods.

Randomization into two cohorts of postoperative rehabilitation will occur via sealed envelope at the time of surgery. Patients will be consented through a formal written process detailing the purpose, risks, and benefits. Randomization will occur in a 1:1 ratio into 2-week versus 6-week immobilization groups. Opaque envelopes will be sealed and only opened at the time of randomization, immediately after completion of the surgical procedure, in the post-anesthesia care unit (PACU). Every patient will be immobilized postoperatively in a nonremovable thumb spica plaster splint to allow for swelling. At the 2 week (+/- 3 days) postoperative visit, patients will be placed into either a cast for 4 additional weeks of immobilization (6-week immobilization group) or be provided a removable thermoplastic thumb spica splint (2-week immobilization group) and specifically instructed to use it for comfort "as needed" with removal at their discretion. A similarly fashioned thermoplastic thumb spica splint will be provided to the 6-week group after the duration of their immobilization, again with instructions for "as needed" use. At the conclusion of each group's respective immobilization period, the same standardized hand therapy rehabilitation regimen will be initiated.