Haley McKissack

This study compares the amount of joint preparation and first ray shortening following first metatarsophalangeal (MTP) joint fusion utilizing open conical reaming versus arthroscopic technique. Ten below-knee cadaver specimens were randomly assigned to undergo either open or arthroscopic first MTP fusion. Following fixation, first ray length measurements were obtained from pre-operative and post-operative radiographs and were used to determine first ray shortening. Additionally, the ratio of first ray length to second ray length was calculated both pre-operatively and post-operatively and compared between the two approaches. All ankles were then completely dissected, and prepared surface areas were demarcated. ImageJ photo analysis software (National Institutes of Health, Bethesda, MD, USA) was used to calculate the percentage of prepared and unprepared cartilage of each articular surface of each specimen. Overall, the open approach resulted in 99.3% ± 1.6% joint surface preparation, whereas the arthroscopic approach yielded 92.9% ± 7.2% (p = 0.089). On average, the head of the first metatarsal was significantly more prepared with the use of the open approach (99.5% ± 1.1%) than with the arthroscopic approach (96.6% ± 1.5%) (p = 0.008). However, with respect to the base of the phalanx, the average difference in preparation between the arthroscopic approach and the open approach was not statistically significant (90.0% ± 12.8% vs. 99.0% ± 2.2%; p = 0.160). The average amount of first ray shortening in the arthroscopic approach was 2.2 ± 1.8 mm compared to 2.1 ± 3.2 mm in the open approach (p = 0.934). The average change in the first to second ray length ratio was 0.02 for both approaches (p = 0.891). Arthroscopic first MTP fusion can be used to achieve joint preparation comparable to open technique while maintaining first ray length.

To compare screw fixation strength for subtalar arthrodesis. Eight matched pairs of cadaver feet underwent subtalar joint arthrodesis with two 7.3mm cannulated screws. Randomization was used to assign screw orientation, such that one foot in each pair was assigned dorsal to plantar screw orientation (DP Group), and the other foot, plantar to dorsal orientation (PD Group). Standard surgical technique with fluoroscopy was used for each approach. Following fixation, each specimen was loaded to failure with a Bionix ® 858 MTS device, applying a downward axial force at a distance to create torque. Torque to failure was compared between DP and PD Groups using Student's t test, with p=0.05 used to determine statistical significance. Statistical analysis demonstrated that the mean torque to failure slightly favored the DP Group (37.3Nm) to the PD Group (32.2Nm). However, the difference between the two groups was not statistically significant (p=0.55). In subtalar arthrodesis, there is no significant difference in construct strength between dorsal-to-plantar and plantar-to-dorsal screw orientation. The approach chosen by the surgeon should be based on factors other than the biomechanical strength of the screw orientation.

Case: A 19-year-old woman sustained a plantar flexion–inversion injury to her right ankle after a low-speed motor vehicle collision. Clinical examination demonstrated supinated, adducted deformity of the foot, and prominent calcaneus laterally. Radiographs revealed dislocation of the calcaneocuboid joint, a rare injury, which was successfully stabilized by a novel technique using a hamstring allograft. The presentations and clinical and surgical management of this rare condition are discussed. Conclusion: We present a technique that has shown good long-term results in a young patient with recurrent calcaneocuboid joint dislocations. Our novel ligament reconstruction technique using a semitendinosus allograft seems to be a promising treatment option in young patients with unstable calcaneocuboid joints.