THUMB CARPALMETACARPAL OSTEOARTHRITIS: TRAPEZIECTOMY VERSUS TRAPEZIECTOMY WITH PI2 ARTHROPLASTY

Abstract

Background: Thumb carpalmetacarpal joint (CMCJ) osteoarthritis has been treated using various combinations of resection, interposition and replacement arthroplasties. The procedure of choice for various stages of CMCJ osteoarthritis remains controversial. This study compares the short term outcomes of trapeziectomy alone and trapeziectomy with PI2 implantation.

Methods: A cross-sectional observational study involving 33 patients (36 thumbs). 18 thumbs had trapeziectomy alone and 18 had trapeziectomy and PI2 implantation. Underlying indication was osteoarthritis in 35 thumbs and trauma in one thumb. Preoperative radiological assessment using the Eaton and Glickel grading for CMCJ osteoarthritis and clinical review including DASH and SF-36 score was performed at a mean follow-up of 18 months. Preoperative and postoperative pain level was assessed using Visual Analogue Scale (VAS) and satisfaction of the surgery using the Likert 5-point scale.

Results: There were 30 women and 3 men. The average age at follow up was 61 years (range 45 to 75). There was no significant difference between the two groups regarding age, duration of symptoms, and stage of disease, preoperative pain score and handedness. The mean DASH score at follow up was 26.8 for trapeziectomy alone group and 35.4 for the PI2 arthroplasty group. Preoperative to postoperative VAS for pain showed an improvement from fair to excellent in 60% of patients in trapeziectomy alone group and 30% of the patients in the PI2 arthroplasty group. There was no significant difference in the SF-36 scores between the two groups in all health domains. 6 out of 16(38 %) patients in the PI2 group had multiple surgeries mainly due to dislocation or subluxation of the implant. The overall Likert 5-point scale scores were highest for trapeziectomy alone group with 70% very satisfied compared to 40% in the PI2 arthroplasty group.

Conclusion: The early results of pyrocarbon PI2 arthroplasty show a high complication rate compared to simple trapeziectomy. The high rates of subluxation and dislocation observed in the early cohort resulting in multiple surgeries may be attributed to steep learning curve of the surgical technique and creation of a shallow groove for the implant. This may have contributed to the low satisfaction levels observed in PI2 arthroplasty group. Simple trapeziectomy provides satisfactory outcome in more than 80% of the patients.