Ligament Reconstruction-Tendon Interposition for
Thumb CMC Arthritis Utilizing the Biotenodesis Screw
Jeffrey Burns, MD
and Mary Lynn Newport, MD
Department of Orthopaedic
Surgery
University of Connecticut
Health Center
Farmington, Connecticut
Introduction: Ligament reconstruction-tendon interposition (LRTI) has become an accepted treatment for osteoarthritis of the thumb carpal-metacarpal joint. Tensioning of the reconstruction with all or a portion of the flexor carpi radialis can be problematic. Utilizing a Biotenodesis screw allows exact tensioning of the reconstruction, making the surgical procedure easier and more reproducible, and the more secure initial fixation allows earlier rehabilitation for the patient.
Methods and Materials: 7 patients (5 female, 2 male) representing 9 thumbs were operated upon for osteoarthritis of the thumb carpal-metacarpal joint. All patients were right hand dominant; there were 5 right thumbs and 4 left thumbs. Average age was 60 years. All patients had undergone a long interval of conservative treatment consisting of rest, NSAIAs, splinting and intra-articular steroid injection before surgery. The surgical procedure was performed through a volar approach to the thumb CMC joint. The trapezium was completely excised. One-half of the FCR was harvested through two or three incisions along the volar forearm. The thumb metacarpal was prepared by removing any large osteophytes but leaving as much proximal articular surface as possible. The initial hole through the thumb metacarpal was made from dorsal to volar with a 2.0 mm Biotenodesis pilot drill. The 4 mm cannulated Biotenodesis drill was then used to drill through both the dorsal and volar cortices. Another hole was made through the articular surface of the metacarpal with burr or curette and connected with the dorsal drill hole. The harvested portion of the FCR was then pulled through the articular-margin hole into the dorsal metacarpal hole. The thumb was then distracted to its normal position and a 4mm x 10 mm Biotenodesis screw was inserted through the dorsal-volar drill hole until flush with the metacarpal cortex, holding the FCR tendon graft in place in an interference fashion. The FCR was then sutured to itself in the depth of the trapeziectomy hole and the remaining FCR folded upon itself and sutured within the cavity. The joint capsule was tightly closed and the thenar muscles were repaired. Post-operatively, the patient was kept in a thumb spica splint for four weeks. Then the patient was placed in a removable Orthoplast short opponens splint and range of motion exercises were begun. Strengthening was begun at eight weeks. Post-operatively, patientŐs pinch strength, range of motion, joint stability, pain level, and activity level were recorded at 3, 6, and 12 months.
Results: All patients were available for follow-up, which averaged 7.8 months (range 4-16). There were no complications. All patients demonstrated full range of motion of the thumb CMC joint including ability to place the palm flat and touch the base of the small finger. All thumbs were stable in all planes. Pre-op pain averaged 8.3 (1-10 point scale), post-op pain averaged 1.3. Pinch strength averaged 87% of the contralateral hand (57%-119%). Absolute pinch strength averaged 12.1 lbs. 8/9 patients had returned to all activities and avocation. One patient, a retired bricklayer, was just beginning to perform brick laying at six months post-operative. 9/9 were satisfied with the procedure and would elect to have it again.
Discussion: These preliminary results show the Biotenodesis screw to be beneficial adjunct to the LRTI procedure. It simplifies the procedure for the surgeon and allows immediate strong fixation of reproducible tension on the reconstruction. This allows earlier rehabilitation for the patient, with better and earlier range of motion and pinch strength.