Mechanical Axis Method to Determine First Intermetatarsal Angle and Tibial Sesamoid Position.

Utilizing the mechanical axis can decrease load on the joint and be beneficial when analyzing bony deformities and planning surgical correction with osteotomies. The aim of this study was to identify the normal mechanical axes of the first and second metatarsals and use them to obtain the first/second mechanical intermetatarsal angle (mIMA). The mechanical axis of the first metatarsal was used to obtain the mechanical tibial sesamoid position (mTSP), which provides a mechanical relationship with the sesamoid apparatus. The angular difference between the anatomic and mechanical axis lines (anatomic-mechanical angle [AMA]) was determined for the first metatarsal and for the second metatarsal. The commonly used first/second anatomic intermetatarsal angle (aIMA) and anatomic tibial sesamoid position (aTSP) were also obtained and compared with the first/second mIMA and mTSP. In this retrospective analysis, radiographs of 50 normal feet (40 patients) were assessed. Pearson's correlation coefficients were used to measure reliability between obtained measurements. Mean first/second aIMA was 8.6 ± 3.0 degrees, and first/second mIMA was 8.6 ± 2.6 degrees. First metatarsal AMA was 1.1 ± 1.0 degrees; second metatarsal AMA was 2.0 ± 1.6 degrees. The mTSP was 2.8 ± 1.1, and aTSP was 2.9 ± 1.0. The TSP median was 3 (range, 1-5). Using the mechanical axis method to obtain the first/second mIMA and the mTSP is reproducible and not affected by anatomic changes to the shape of the metatarsal. Unlike the anatomical axis, the mechanical axis does not change, therefore we recommend using the mechanical axis during surgical planning and when obtaining preoperative and postoperative measurements for the long bones of the foot, particularly for forefoot conditions such as hallux valgus.

Increased Arthrodesis Rates in Charcot Neuroarthropathy Utilizing Distal Tibial Distraction Osteogenesis Principles.

Charcot neuroarthropathy of the hindfoot and ankle poses substantial challenges due to deformity, segmental bone loss, chronic infection, and difficulty with bracing. Hindfoot or ankle arthrodesis is often employed at high rates of complications and nonunion. This study reports 15 consecutive patients with Charcot neuroarthropathy who underwent tibiotalocalcaneal or tibiocalcaneal fusion with simultaneous distal tibial distraction osteogenesis with a mean follow-up period of 20.2 ± 5.66 months. Arthrodesis rate was 93.3% (14 patients) with mean time to fusion of 4.75 ± 3.4 months. One hypertrophic nonunion occurred at the arthrodesis site. Complete consolidation of 4 cortices was achieved at the distraction site in 93.3% of patients (14 patients) with a mean duration to consolidation of 9.8 ± 3.3 months. One patient experienced hypertrophic nonunion at the regeneration site. The authors report a technique to enhance arthrodesis rates in Charcot neuroarthropathy by combining distal tibial distraction osteogenesis with simultaneous tibiotalocalcaneal or tibiocalcaneal arthrodesis for hindfoot fusion and salvage. Distraction osteogenesis supports enhanced vascularity to the arthrodesis site.Level of Clinical Evidence: Level 4.

Short-Term, Retrospective Radiographic Evaluation Comparing Pre- and Postoperative Measurements in the Chevron and Minimally Invasive Distal Metatarsal Osteotomy for Hallux Valgus Correction.

Various techniques exist for correction of mild to moderate hallux valgus (HAV) deformity. Recently, minimally invasive distal metatarsal osteotomy (MIDMO) has gained popularity for HAV correction. This retrospective radiographic review aims to report the surgical correction obtained by the chevron and MIDMO osteotomies at a single institution between January 2012 and December 2017. Radiographic parameters, such as intermetatarsal angle (IMA), hallux abductus angle (HAA), and tibial sesamoid position (TSP), were compared on weight-bearing anterior-posterior and lateral radiographs. Sixty-one patients who underwent distal first metatarsal osteotomies were separated into 2 groups. Group A included 30 patients with a chevron bunionectomy performed by Surgeon A; Group B consisted of 31 patients who had MIDMO performed by Surgeon B. Mean follow-up was 26.6 months for Group A and 18.7 months for Group B. Both groups had statistically significant radiographic correction for pre- and postoperative IMA, HAA, and TSP. Group A: IMA measured preoperatively 11.6° ± 4.0° to 6.8° ± 4.1° postoperatively, HAA preoperative 22.2° ± 9.1° to 12.3° ± 6.9° postoperative, and TSP preoperative 1.3 ± 0.9 to 0.7 ± 0.6 postoperative. Group B: IMA measured preoperatively 12.0° ± 2.9° to 5.9° ± 3.3° postoperatively, HAA preoperative 27.9° ± 8.6° to 12.0° ± 6.6° postoperative, and TSP preoperative 2.0 ± 0.8 to 0.7 ± 0.6 postoperative. Postsurgical retrospective radiographic review demonstrated chevron and MIDMO procedures provide comparable radiographic correction of IMA, HAA, and TSP.