Five-Year Follow-up of Third-Generation Percutaneous Chevron and Akin Osteotomies (PECA) for Hallux Valgus.

BACKGROUND: Recent large studies of third-generation minimally invasive hallux valgus surgery (MIS) have demonstrated significant improvement in clinical and radiologic outcomes. It remains unknown whether these clinical and radiologic outcomes are maintained in the medium to long term. The aim of this study was to investigate the minimum 5-year clinical and radiologic outcomes following third-generation MIS hallux valgus surgery in the hands of a high-volume MIS surgeon. METHODS: A retrospective observational single highly experienced MIS surgeon case series of consecutive patients undergoing primary isolated third-generation percutaneous chevron and Akin osteotomies (PECA) for hallux valgus with a minimum 60-month clinical and radiographic follow-up. Primary outcome was radiographic assessment of the hallux valgus angle (HVA) and intermetatarsal angle (IMA) preoperatively, 6 months, and ≥60 months following PECA. Secondary outcomes included the Manchester-Oxford Foot Questionnaire, patient satisfaction, EuroQol-5D visual analog scale and the visual analog scale for pain. RESULTS: Between 2012 and 2014, 126 consecutive feet underwent isolated third-generation PECA, with complete data available for 78 (61.9%) feet. The median follow-up was 65.0 (IQR 64-69; range 60-88) months. There was a significant improvement in radiographic deformity correction; the median IMA improved from 12.0 degrees (interquartile range [IQR]: 10.8-14.2) to 6.0 degrees (IQR: 4.2-7.3) (P < .001), and the median HVA improved from 27.2 degrees (IQR: 20.6-34.4) to 7.2 degrees (IQR: 3.4-11.6). Median MOXFQ Index score at ≥60-month follow-up was 2.3 (IQR: 0.0-7.8). The radiographic recurrence rate (defined as HVA >15 degrees) was 7.7% at final follow-up. The complication rate was 4.8%. CONCLUSION: Radiologic deformity correction for the 78 feet we were able to follow that had third-generation PECA performed by a single highly experienced MIS surgeon was found to be maintained at a mean follow-up of average 66.8 months, with a radiographic recurrence rate of 7.7%. Clinical PROMs and patient satisfaction levels were high and comparable to other third-generation studies with shorter duration of follow-up. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

Valgus Second Toe Deformity Treated With a Percutaneous Extracapsular Closing-Wedge Osteotomy of the Proximal Phalanx.

BACKGROUND: Coronal and sagittal plane deformities of the lesser toes are common yet challenging to treat. Traditional open releases and translational Weil osteotomies can be unpredictable and lead to postoperative stiffness. We present the results of a percutaneous closing wedge extracapsular osteotomy of the proximal phalanx to treat valgus deformity of the second toe. METHODS: Thirty-one patients underwent 40 percutaneous osteotomies at a median age of 58.6±9.4 years. Using a small dorsomedial incision, a percutaneous proximal metaphyseal medial closing-wedge extracapsular osteotomy of the second toe is performed, leaving the dorsolateral cortex intact. An irrigated low-speed, high-torque 2- × 8-mm burr is used under image guidance. The osteotomy is then closed to correct deformity and taped for 2 weeks. Patient-reported outcomes and weightbearing radiographs were obtained. RESULTS: Questionnaire data was available for 89.7% (n=35) of cases. Most cases (91.4%) were either satisfied or extremely satisfied with the procedure. Radiographs were available for 90.0% of osteotomies, with a median length from surgery to radiographic follow-up of 1.6 years (range 0.5-6.3; SD ±1.5). Median second-toe valgus angle (STVA) decreased from 16.2±10.7 degrees to 5.0±7.0 degrees (P < .001) at final follow-up. All osteotomies united with no delayed union. There were no wound complications or infections. We found 2 cases of radiographic recurrence. CONCLUSION: Percutaneous proximal phalanx base metaphyseal closing wedge extracapsular osteotomies of lesser toes to correct coronal plane deformity is useful adjunct to first-ray corrective surgery and is associated with high levels of patient satisfaction. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Percutaneous Chevron and Akin (PECA) Osteotomies for Severe Hallux Valgus Deformity With Mean 3-Year Follow-up.

BACKGROUND: Patients with severe hallux valgus deformity present technical and operative challenges with high rates of recurrence and residual deformity. The clinical and radiologic outcomes of percutaneous surgery for severe hallux valgus are not known. METHODS: A retrospective review of consecutive patients with a hallux valgus angle (HVA) >40 degrees or intermetatarsal angle (IMA) >20 degrees who underwent third-generation percutaneous chevron and Akin osteotomy (PECA) for hallux valgus deformity correction. RESULTS: Between December 2012 and August 2019, 59 feet in 50 patients underwent PECA. Preoperative and follow-up radiographic data were available for 53 feet (89.8%). Postoperative clinical patient-reported outcome measures and satisfaction results were available for 51 feet (86.4%). The mean clinical and radiographic follow-up was 3.1 years and the mean postoperative Manchester-Oxford Foot Questionnaire Index score was 15.1. There was a statistically significant improvement (P < .001) in both IMA and HVA following surgery (IMA 17.5-5.1 degrees; HVA 44.1-11.5 degrees). All patients reported they were satisfied with their outcome, with 76.8% reporting they were highly satisfied. The hallux valgus recurrence rate was 7.5%. CONCLUSION: Percutaneous surgery for severe hallux valgus deformity can achieve a large deformity correction, patient satisfaction, and quality of life, with reasonable rates of residual deformity and low rates of recurrence. LEVEL OF EVIDENCE: Level IV, case series.

Accurately characterizing the importance of wave-particle interactions in radiation belt dynamics: The pitfalls of statistical wave representations.

Wave-particle interactions play a crucial role in energetic particle dynamics in the Earth's radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm-time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm-time wave power.