[Arthrodesis of the Distal Interphalangeal Joint of the Finger Using an Intramedullary Implant].

Purpose of the study: Osteoarthritis (OA) of the joints of the hand is one of the most common musculoskeletal disorders in the elderly population. It is a complex, degenerative disease affecting all components of the joint. Surgical treatment is indicated when conservative therapy fails. The ultimate solution is arthrodesis of the distal interphalangeal (DIP) joint. Various methods of arthrodesis have been described, ranging from the use of K-wires or compression screw to different types of intra-articular (intramedullary) implants. The aim of this study is to evaluate the surgical outcomes of arthrodesis of the distal interphalangeal (DIP) joint of the fingers using intramedullary implants.

Material and methods: Since 2011, arthrodesis of the distal interphalangeal joint using an intramedullary implant has been performed at our department 97 times in total, in 59 patients. 9 patients (15 cases of arthrodesis) were excluded from the study group due to their failure to complete the questionnaire, 1 female patient died. In the final group, 82 cases of arthrodesis in 49 patients (47 women, 2 men) were evaluated. In 72% of cases, the surgery was performed on the dominant hand. The mean age at the time of surgery was 58 years (median 59 years). The patients were indicated for surgery after the failure of all conservative treatment options. In addition to radiographs, also the hand function and pain were assessed based on the preand postoperative DASH score questionnaires.

Results: The surgical outcomes for all implants are satisfactory. In all 82 patients, the surgical wounds healed per primam. In one case, implant extraction was performed due to infection. Another complication was an unhealed fusion and formation of a non-union with minimum pathological mobility (the patient is satisfied with the outcome). In three patients, a fracture at the base of the distal phalanx was observed on postoperative radiographs, which fully healed within 3 months after surgery. The mean DASH score decreased from 41.95 preoperatively to 14.93 postoperatively. The mean time to healing of the arthrodesis observed on radiographs was 9.1 weeks.

Discussion: Currently, there are many different types of arthrodesis of the distal interphalangeal joint of the hand. Each method has its pros and cons. Arthrodesis using an intramedullary implant has the advantages of the older methods while minimizing postoperative complications. Our results are comparable to those reported in the foreign literature.

Conclusions: Based on the evaluated outcomes, arthrodesis of the distal interphalangeal joint using an intramedullary implant can be considered valid. It definitely deserves to be included in the portfolio of surgical treatment of osteoarthritis of the DIP joints of the hand. According to our observation, the differences between various types of implants are minimal and their outcomes are comparable to those reported in foreign publications. The pain relief, restored finger function and fusion rate are comparable to, if not better than, those achieved by the older surgical methods. The advantage of this method is mainly easier implantation, fewer complications, and the possibility of implantation without the use of an X-ray image intensifier, which ultimately reduces the cost of surgery. The main disadvantage is the higher purchase price of the implant.

Key words: osteoarthritis, distal interphalangeal joint, arthrodesis.