Basal Joint Pain of the Thumb

By: Jeff Cowdry, OT, CHT Hand Therapist at ApexNetwork Physical Therapy in Ballwin, MO

Thumb basal joint pain is very common and can be debilitating. The basal joint is the area where the thumb metacarpal bone contacts the small wrist bone called the trapezium. Basal joint thumb pain affects young and old alike as well as people in a wide variety of occupations.

Physical and occupational therapists often experience basal joint pain during their daily work on tight tissues and joints. The basal joint is one of the most mobile and complex joints in the body. The boney and ligamentous support and the multiple influencing muscles give thumbs great range of motion and positioning capability. Unfortunately, this comes with a price. Forces at the tip of the thumb can translate to over ten fold at the basal joint. In some people the repetitively strained joint eventually wears out. Also, arthritis often attacks this joint.

As the joint wears down, the many ligaments become over-stretched and the joint cartilage thins. The metacarpal bone starts to slide off the trapezium, and in advanced cases the joint totally dislocates. The thumb web space narrows and grasping wide objects becomes difficult. Over-use and under-use of certain thumb muscles leads to weakness, tightness, and other problems. The MP joint (the large knuckle) starts to hyperextend and become unstable. The IP joint (the small knuckle) assumes a flexed posture. Left untreated, the thumb basal joint eventually fuses and the pain abates. However, the various deformities leave a poor-functioning thumb and, therefore, hand.

The physical and occupational therapists at ApexNetwork Physical Therapy recognize and treat basal joint problems throughout the course of symptoms. After examining the hand, therapists decide what kind of flexibility stretches and exercises are needed. Joint protection education and adaptive equipment tips are given. Home programs including paraffin bath treatments,

nighttime orthoses, daytime orthoses, and exercises are given. Therapy intervention does not cure the problem but can decrease pain, decrease or delay deformity, and improve function. Should the thumb someday require surgical intervention, ApexNetwok Physical Therapy

therapists work closely with hand surgeons who reconstruct the joint to insure that good strength and hand function return.