I have a wonderful hand surgeon who is trying to help me with my thumb problem. Well, actually, I have two thumb problems. The medical report says I have "MCP joint hyperextension associated with TM arthrosis." My surgeon showed me how much arthritis I have at the trapezial-metacarpal (TM) joint (thumb-to-wrist connection) but no arthritis at the metacarpophalangeal (MCP) joint (large knuckle joint). I'm very proud of myself for understanding the whole anatomy thing. The question is what can be done about it?
Conservative (nonoperative) care with splinting, activity modification, and strengthening exercises may be helpful. They are at least worth a good try. But if after three to six months, you do not experience significant improvement, then surgery may be your best option.
The first area to address with surgery is the painful, arthritic trapezial-metacarpal (TM) joint. Most hand surgeons agree that when trapezial-metacarpal (TM) reconstruction surgery is done, the MCP hyperextension should also be stabilized. The guideline is if there is more than 30-degrees of hyperextension of the MCP joint, then both problems should be surgically treated at the same time.
If the MCP problem isn't fixed, then the force and load is transferred to the reconstructed TM joint and that can cause some problems. Stabilization procedures for the MCP include using pins to hold the joint while the TM reconstruction heals, release of the muscle (extensor pollicis brevis) affecting the MCP, fusion of the joint, and capsular release of the palmar side of the joint.
There aren't a lot of studies focused on the treatment of this problem. Limited evidence available suggest that temporary pinning of the MCP joint when there is less than a 30-degree hyperextension deformity does no good. In small studies, one year after the procedure, patients have no improvement in the hyperextension deformity.
Performing a tenotomy (tendon release and reattaching the tendon end to a different area of bone) has some benefit for most patients. Fusion of the joint doesn't always work. Recurrence of the excess motion is possible.
Releasing the joint capsule on the palmar side of the thumb seems to have the best results. This procedure is called a volar capsulodesis. In three separate small case series of 10 to 13 patients, there were excellent results with no recurrence the majority of the patients. Excellent results mean pain was reduced and the patients had good pinch grip function.
When there isn't enough evidence to really give surgeons a definite treatment guideline or protocol, they take the information from studies available and combine it with logic and common sense to form a treatment plan. In cases like yours, preserving thumb motion is usually the number one priority. Treating the MCP hyperextension is important to prevent risk of TM reconstructive failure. The volar capsulodesis may be the best option to reduce MCP deformity and improve MCP joint alignment.
But even with the positives associated with the volar capsulodesis procedure, there are no long-term studies to show what happens down the road. Further research is needed to show if treating the MCP is helpful or a waste of time and money.
Your surgeon is really the best one to advise you. Understanding the anatomy is a good starting point! Information like this from other studies may help you now to discuss the best treatment plan for you.
Ryan Klinefelter, MD. Metacarpophalangeal Hyperextension Deformity Associated with Trapezial-Metacarpal Arthritis. In The Journal of Hand Surgery. December 2011. Vol. 36A. No. 12. Pp. 2041-2043.
*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.