Background: The calcaneal slide osteotomy is a common procedure used for the surgical correction of heel varus and valgus deformities. A variety of fixation methods exist including screws and plates. The literature shows a high rate of hardware prominence with screws leading to subsequent removal of hardware. Few studies have examined the use of plates for fixation of a calcaneal osteotomy. The purpose of this study was to assess outcomes following fixation of a calcaneal osteotomy with a calcaneal slide plate. Methods: This is a retrospective consecutive case series of all patients who underwent either a medial or lateral calcaneal slide osteotomy using the specialized calcaneal slide plate between September 2013 and December 2018 by a single surgeon. The primary outcome measures were the rate of hardware removal, healing of the calcaneal osteotomy, and any associated complications such as infection or incision healing delays. Patient baseline demographics and procedure-related data were recorded. The minimum follow-up was 4 months. A total of 81 procedures were performed using this calcaneal slide plate. Results: All of the patients had one or more additional procedures at the same time as the calcaneal osteotomy. All of the calcaneal osteotomies healed without displacement. Only 1 patient (1.2%) returned to the operating room and had removal of the calcaneal slide plate, which was after osteotomy union for an infected wound. There were no cases of hardware failure or removal due to it being symptomatic. Conclusion: A specialized calcaneal slide plate was an effective fixation device for both medial and lateral calcaneal slide osteotomies for a variety of foot and ankle conditions. The union rate was 100% and none of the patients had hardware symptoms, which is an improvement on published reports of symptomatic hardware after calcaneal slide osteotomy. Level of Evidence: Level IV, retrospective case series.

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Category: Ankle Arthritis; Ankle Introduction/Purpose: The Scandinavian Total Ankle Replacement (STAR) is the most widely used mobile bearing total ankle arthroplasty (TAA) in the US. The polyethylene component is ultrahigh molecular weight polyethylene and is designed to articulate with both the tibial and talar component. Initial data on the STAR in the US reported polyethylene fracture rates of greater than 10% as well as a concern for cyst formation due to osteolysis. The manufacturer changed the packaging to foil to prevent potential oxidation of the polyethylene, which could predispose the polyethylene to failure. The objective of the study was to evaluate a cohort of patients with STAR performed before and after converting to foil packaging to determine if there is a difference in polyethylene survivorship and cyst formation. Methods: All primary TARs performed by the senior author from 2010-2017 were reviewed. Patients with a minimum 48 month follow up were included in the study. The two groups were stratified by those performed prior to August 2014 (PRE) and those performed after August 2014 (POST). Preoperative and most recent postoperative alignment was determined on weight bearing radiographs. The outcomes included polyethylene fractures and cyst formation in the two groups. Cysts were defined as those measuring greater than 1cm2 on plain radiographs. Patients were recommended to have surgery if cyst volume was greater than 2cm2. Chi-squared tests were used to detect significant differences in the rate of cyst formation between the two groups. Paired t- tests were used to determine difference in preoperative versus postoperative alignment, follow up length, and polyethylene component thickness and patient age at time of procedure between the two groups. Results: The PRE group had 35 patients with an average follow up of 75 months (range 48-118). The POST group had 15 patients with average follow up 55 months (range 48-60). There was no difference in preoperative versus postoperative radiographic alignment between the groups (p>0.05). Cysts were present in 9 (26%) patients in the PRE group versus 4 patients (26%) in the POST group. Nine patients (26%) needed a second surgery due to cyst formation in the PRE group versus two (16%) in the POST group (p>0.05). Four patients (11%) had a fracture of the polyethylene in the PRE group with an average thickness of 6.7mm (range 6-9) and 77 months (range 68-84) versus zero in the POST group. The average time to polyethylene exchange for cyst(s) or polyethylene fracture was 58.3 months. Conclusion: This study suggests that changes in packaging to limit oxidation of the polyethylene from plastic to foil did not appear to represent a difference in periprosthetic cyst formation. However, there was a trend for additional surgery related to periprosthetic cysts and increased risk for polyethylene fracture in the PRE group. These results could suggest the potential for oxidation changes that alter the wear characteristics and fragility of the polyethylene component. Confounding factors could include postoperative time and component thickness. Further investigation and longer follow-up will be needed to further delineate oxygenation impacts on TAA polyethylene components.

Category: Other; Trauma Introduction/Purpose: The success of hexapod multiplanar external fixators for correction of tibial deformity has been well described. The ability to correct deformity is based on the accuracy of the reference and deformity data inputted into the prescription program. If the data is not accurate, multiple residual programs may be required for final correction. There are limited papers evaluating i accuracy of intraoperative measurements. We are unaware of any analysis on the use of CT scan to determine deformity and reference points. Newer software program allows surgeons to incorporate radiographs into the correction program to determine deformity and reference points. Our study objective was to compare deformity and reference point measurements taken from radiographs, CT, and imaging software to determine which method most accurately corrects tibia deformities. Methods: Hexapod external fixators were orthogonally applied on four full length tibia cadavers. Strut lengths were set to the same length. Each cadaver was assigned a different deformity: proximal quartile, distal quartile, midshaft, and segmental. An osteotomy was performed and the hexapod struts were loosened to create a multiplanar deformity. Radiographs and CT were taken orthogonal to the reference ring. Deformity and reference points were measured off each according to correction software data points. Pictures of the radiographs were imported into the software program (Stryker, Mahwah, NJ) and the correction reference points were determined with imaging software. All cadavers had a correction program for each method. Two surgeons performed the measurements twice to determine inter and intra-observer accuracy. Corrections were performed and post reduction radiographs were measured to determine length, angulation and translation. In addition, the total number of millimeters each strut was off from the pre-deformity position was recorded. Results: Line technique on software program was significantly better at measuring segmental deformity and the Image technique was statistically more accurate to correct proximal, midshaft and distal deformities (p<0.05). Overall, all methods were more accurate correcting Midshaft and Proximal deformities (44.8mm and 50.4mm, respectively) significantly better than Distal and Segmental deformity correction (88.9mm and 121.7mm, respectively (p<0.001). There was no difference in absolute measurements or intra-observer error between the four surgeons (p>0.05). Conclusion: Compared to the traditional method of measuring deformity and frame reference using radiographs, new imaging software appears to be superior and more reproducible in correcting tibia deformities. Surgeons should recognize the increased difficulty in correcting segmental and distal deformities regardless of the method used. Accuracy of determining deformity and frame reference points has the potential to decrease time patients are in a frame and reduces the potential for malunions. Further investigation is needed to determine sites of variation to further improve the process of correcting complex deformities of the tibia.