Therapeutic Outcomes of KalixIIin Treating Juvenile Flexible Flatfoot

Abstract

Objectives: To evaluate the therapeutic outcomes with Kalix II subtalar arthroereisis in sinus tarsi for juvenile flexible flatfoot.Methods: A retrospective analysis of the data of 20 juveniles with symptomatic flexible flatfoot (27 feet) who underwent the Kalix II implant procedure from January 2008 to September 2012 was performed. The pain during daily activities was assessed and followed up by use of a standard 10-point visual analog scale (VAS), and function was evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot scoring system, and anteroposterior talar-first metatarsal angle, lateral talar-first metatarsal angle, calcaneal pitch angle, and talar declination angle at X-ray film were measured to assess the therapeutic outcomes. Patients were asked to grade the result of the procedure as excellent, good, fair, or poor at latest follow-up. The data was expressed as mean AE standard deviation (SD). A paired Student's t-test was used for comparisons of the preoperative and postoperative angular measurements for each foot, VAS scores, and AOFAS scores. In all tests, P < 0.05 was considered statistically significant.Results: The mean age of the patients was 12.1 years (range, 7-16 years), and 16 left feet and 11 right feet were involved. All patients finished the follow-up with a mean period of 28.1 months (range, 23-60 months). Eleven feet were treated with subtalar arthroereisis combined with reconstruction of the end point of the posterior tibialis tendon after dissection of the accessory scaphoid. The subtalar arthroereisis device displaced in 1 foot due to a fall from the inversion position 3 months after surgery, and was replaced by a new device after the failure of conservative treatment. The mean VAS score decreased from 5.6 AE 0.5 preoperatively to 1.2 AE 0.2 (P < 0.001), and the mean AOFAS hindfoot and ankle score improved from 71.1 AE 6.1 preoperatively to 88.1 AE 6.3 (P < 0.001). Differences between preoperative and postoperative measurements for each radiographic variable were statistically significant (P < 0.001).Comparison of radiographic measurements showed that the anteroposterior talar-first metatarsal (Meary) angle decreased by a mean of 12.8 AE 1.5 , the lateral talar-first metatarsal (Meary) angle decreased by a mean of 15.4 AE 1.3 , the calcaneal pitch angle increased by a mean of −2.1 AE 0.7 , and the talar declination angle decreased by a mean of 17.9 AE 2.8 . Overall, 12 patients rated the result as excellent, 6 as good, and 2 as fair. Conclusion:The application of Kalix II in subtalar arthroereisis combined with dissection of accessory scaphoid and reconstruction of posterior tibialis tendon is an effective therapy for flexible juvenile flatfoot.

Clinical and Radiological Outcomes of Subtalar Kalix II Arthroereisis for a Symptomatic Pediatric Flexible Flatfoot

“…Maxwell-Brancheau (MBA) screw. 18,[20][21][22][23]33 However, the present study is one of the few studies that described comparable CP and MA angles at midterm follow-up (ie, 47 months) when compared with the direct postoperative angles in pediatric patients. Other surgical interventions affecting the CP and MA, such as the more invasive calcaneal lengthening osteotomy, have reported comparable or even better radiological outcomes than the present technique.…”

“…In cases were treatment fulfillment is not reached with this procedure, more invasive and irreversible techniques still remain good alternatives. Furthermore studies of radiographic parameters are of great importance for the assessment of postoperative improvements in anatomical foot position, 15,[18][19][20][21][22][23][24]33,38 they do not necessarily predict postoperative patient satisfaction after a surgical treatment. 14,18 Therefore, this study also assessed patient satisfaction using a PROM.…”

“…Besides examining patients' experience by the use of PROMs, several studies assessed clinical outcome after subtalar arthroereisis using the well-known AOFAS, which showed improvements in all studies. 15,19,21,33,37,38,41 The AOFAS reports an overall score based on several questions and a physical examination but does not measure the patient's level of function in society and the effect of therapeutic interventions may have on the patient's life. [42][43][44] A major advantage of the current study was the use of a PROM to gain extensive Patient-Reported Outcome Measurement questionnaire outcome per question.…”

“…Additionally, CP and MA were also assessed on midterm follow-up radiographs, and therefore, our analyses are not limited to preoperative and direct postoperative measurements, which is a limitation of previous studies. 18,[20][21][22][23][24]33 Also, it was the first study that calculated ICCs and observed moderate to excellent reliability of the performed radiological measurements, which indicates that reliable radiological results were achieved. 32 Despite the promising PROMs after Kalix implantation, there are some limitations to this study and Kalix use in general.…”

“…The appropriate implant size is chosen via the assessment of hindfoot movement perioperatively, which is a subjective method for choosing the best-fitted implant. 14,21,33 In our series, in 83% (5/6) of these cases, a different implant size was intraoperatively chosen. This emphasizes the importance of appropriate sizing of the Kalix implant during the primary surgery.…”