Subtalar joint preparation using the Two Portal posterior arthroscopic technique versus the sinus tarsi Open...

Subtalar fusion is the treatment of choice for subtalar arthritis when conservative management fails. The procedure can be performed arthroscopically or through the open lateral sinus tarsi (LST) approach. The arthroscopic technique is less invasive and is associated with rapid recovery, but it is more technically challenging. One of the most important aspects of fusion is adequate preparation of the joint via denudation of articular cartilage. This study compares the efficacy of subtalar joint preparation between the lateral sinus tarsi approach and the posterior two-portal arthroscopic technique using cadaveric specimens.

Nineteen below-knee fresh-frozen cadaver specimens were used. The subtalar joints of nine specimens were prepared through the LST approach, while ten were prepared arthroscopically. After preparation, all ankles were dissected at the subtalar joint and photographs were taken of the posterior facets of the calcaneus and talus. Total and prepared surface areas of the articular surfaces for both approaches were measured using ImageJ software and compared.

The LST technique resulted in significantly greater percent preparation of the posterior facet of the calcaneus, as well as of the subtalar joint as a whole. Overall, 92.3% of the subtalar joint surfaces (talus and calcaneus combined) were prepared using the LST technique, compared to 80.4% using the arthroscopic technique (p = 0.010). The posterior facet of the calcaneus was 94.0% prepared using the open technique, while only 78.6% prepared using the arthroscopic technique (p = 0.005).

The LST approach for subtalar arthrodesis provides superior articular preparation compared to the two-portal posterior arthroscopic technique. Given that joint preparation is a critical component of fusion, maximizing prepared surface area is desirable and the open approach may be more efficacious for fusion. When using the arthroscopic approach, it may be advisable to use an accessory portal if there is poor visualization or limited access to the joint space secondary to severe arthritis.

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