Double trapeziometacarpal and scaphotrapeziotrapezoidal pyrocarbon interposition implants for pantrapezial arthritis: Midterm results and surgical technique.

BACKGROUND: Pantrapezial osteoarthritis of the thumb (OA) includes involvements of scaphotrapezoidtrapezoidal (STT) and trapeziometacarpal (TM) joints which are source of disabling pain and function loss. Whilst radical procedures or arthroplasties are available, more conservative techniques have been developed recently and have gain popularity. They aim of this study was to know the midterms results of patients presenting peritrapezial OA treated with a double interposition pyrocarbon implant at the STT and TM joints. Our hypothesis was that patients suffering from pantrapezial OA treated with this technique would improve their functional scores at the last follow-up.

PATIENTS AND METHODS: This descriptive, retrospective, observational study analysed 31 patients treated with a double STT and TM pyrocarbon interposition implant ("Burger arthroplasty") between 2009-2018. Patients were clinically and radiologically diagnosed with pantrapezial OA before surgery (Eaton stage I or II). The primary endpoint was the comparison of the preoperative and postoperative values of the functional scores QuickDASH and PRWE. Epidemiological data and radiological results were reported. Pain, range of motion, pinch and grip strength, were analysed with standardised tools. The surgical technique was described in detail and reinforced with a didactic supplementary video.

RESULTS: Eighteen patients were available for analysis (58%) with a mean age of 62 years (range: 49-79). At last follow-up (44 months, range: 9-95) we found significant reduced pain, significant improvement of QuickDASH and PRWE scores and of pinch strength (p<0.05). Range of motion, grip and pinch strength did not improve significantly (p>0.05). Two patients required revision surgery.

DISCUSSION: The double STT and TM pyrocarbon interposition offer good results at midterm on patient suffering from early stages of pantrapezial OA with preserved trapezium structure.

LEVEL OF EVIDENCE: IV.