Do the presence of pathologic changes and the level of operator experience alter the rate of intra-articular injection of the first metatarsophalangeal joint? A cadaver study.

Background: Injections, punctures, and aspirations of the first metatarsophalangeal joint are common interventions. Accurate intra-articular placement of the needle is a prerequisite for the achievement of desirable results and the avoidance of complications. We evaluated the rate of successful intra-articular injections and the influence of the degree of operator experience in achieving this success.

Methods: A total of 106 cadaveric metatarsophalangeal joints were injected with a methylene blue-containing solution and subsequently dissected to distinguish intra-articular from periarticular injections. To evaluate the importance of experience, 38 injections were performed by a student, 38 by a trained resident, and 30 by an experienced surgeon. In the second part of the study, we examined the relation of pathologic findings of the metatarsophalangeal joint and the accuracy of intra-articular injection.

Results: The overall rate of unintentional periarticular injections remained low (9.4%; 10 of 106 joints). The student achieved a successful intra-articular injection in 86.8% of joints (33 of 38), the resident in 92.1% (35 of 38), and the specialist in 93.3% (28 of 30). The number of extra-articular injections increased significantly with the presence of deformity (hallux valgus) and arthritis of the first metatarsophalangeal joint.

Conclusions: The presence of pathologic changes reduces the rate of successful intra-articular joint puncture. However, the overall frequency of successful intra-articular injections can be improved through experience and the use of imaging.