This study evaluated the effects of tendon interposition used during ligament reconstruction for primary basal thumb joint arthroplasty. Fifteen patients were treated with ligament reconstruction alone (group 1) and 16 patients were treated with ligament reconstruction with tendon interposition (group 2). Patients were evaluated at a mean follow-up period of 48 months by questionnaire, physical examination and radiographic evaluation. The ligament reconstruction was performed according to the technique of Epping and Noack using half of the flexor carpi radialis tendon for ligament reconstruction and a more proximal portion of half of the FCR tendon for the tendon interposition. The mean Buck-Gramcko scores in group 1 were 51 points compared to 45 points in group 2 (maximum of 56 points). The mean palmar abduction and radial abduction were significantly greater in group 1 than in group 2. In addition, tip-pinch strengths increased an average of 32% in group 1 and 9% in group 2. Grip strengths decreased an average of 20 % in group 1 and 48% in group 2. Subjective assessments of pain, strength, daily function, dexterity and surgical outcome were not significantly different between the two groups. There were no significant differences with respect to return to previous jobs or with previous recreational activities. Radiographic evaluation revealed post-operative proximal migration of the thumb metacarpal at rest resulted in an average loss of 42 % of the initial post-operative height of the arthroplasty space in group 1 and a 37% loss of the height in group 2. Under stress, proximal migration was found to result in 40% loss of height in group 1 and 27% loss of height in group 2. There was no relationship found between the postoperative height of the arthroplasty to either pain or tip-pinch strength. Two patients in each group had temporary paresthesies about the incision site and 1 patient in group 2 developed RSD.
This paper shows no advantage of tendon interposition over ligament reconstruction alone. In fact, better subjective and functional scores were found in the group with ligament reconstruction alone, although metacarpal height was better maintained with tendon interposition but did not correlate with the overall outcome. The authors did not provide any hypothesis as to the observation that patients with ligament reconstruction alone appeared on average to have better outcomes than those with ligament reconstruction and tendon interposition. The only surgical difference appears to be related to an additional incision required in the forearm for the harvest of the additional half of the FCR tendon for the interposition. It should be noted that this study is in a small group of patients with a relatively short follow-up of 4 years considering the mean age was approximately 59 years of age.
J of Bone and Joint Surgery