Pes cavus in its different forms is not a pathological entity, but rather the manifestation of multiple diseases. Cavovarus, a form of cavus foot, should never be considered a physiological deformity. A neurological condition should always be excluded. The evolution of pes cavovarus is unpredictable because of the large number of conditions involved in its aetiology, as well as their variable degree of expression. About 66% of cavovarus feet are the result of subtle neurological diseases, which only become evident later in life. Although surgery may not change quality of life, recent studies suggest that it may improve foot posture and reduce walking instability. The aim of treatment is to preserve a painless, plantigrade, mobile foot. Management consists of correcting bone deformity while preserving movement, and the wise use of rebalancing techniques. Arthrodesis should only be a salvage procedure. Cite this article: EFORT Open Rev 2021;6:510-517. DOI: 10.1302/2058-5241.6.210021

Background and purpose - Pes cavovarus (PCV) is a complex deformity, frequently related to neurological conditions and associated with foot pain, callosities, and walking instability. The deformity has the tendency to increase during growth. Orthotic treatment is ineffective and surgery may be troublesome. We present the preliminary results of a new mini-invasive surgical technique for correction of this foot deformity. Patients and methods - We operated on 13 children (24 feet), age 7-13 years. In 7 children the deformity was neurological in origin. The surgical technique included a dorsal hemiepiphysiodesis of the 1st metatarsal, and a plantar fascia release. The clinical deformity, hindfoot flexibility, and foot callosities, together with a radiological assessment (Meary angle, calcaneal pitch, and talo-calcaneal angle), was done pre- and postoperatively. At final check-up, after a median of 28 months (12-40), the Oxford Ankle Foot Questionnaire for children (OXAFQ-C) was used to assess patient satisfaction. The primary outcome was the hindfoot varus correction. Results - All the operated feet improved clinically and radiologically. Heel varus improved from a mean 6° preoperatively to 5° valgus postoperatively. In those children where treatment was initiated at a younger age, full correction was achieved. Footwear always improved. Interpretation - This treatment may offer a less aggressive alternative in the treatment of PCV in young children and may eventually reduce the amount of surgery needed in the future.

During the last few years, the use of the 8-plate as a technique for hemiepiphysiodesis has gained wide acceptance, as it has been shown that it works in a more physiological way than other methods such as staples or transphyseal screws. It has mechanically been compared with a tension band plate, and for this reason, only a single plate is needed. The following study was undertaken to test the 8-plate against the staples and assess factors that can influence the difference in results. A prospective experimental study was designed to compare the ability of 2 hemiepiphysiodesis methods, the 8-plate and the double staple, to produce angular deformity in the rabbit's tibia (group I). The variable studied was the variations in the articular line-diaphysis angle at 6 weeks. As the results showed that the 8-plate produced a bigger deformity, a second group was designed (group II) comparing single against double staple, under the hypothesis that the differences observed in the first group could be related to the number of anchors put across the physis and consequently depend on the volume of physis involved by the staples. In group I, the 8-plate produced a bigger angulation at 6 weeks' time than the 2 staples (a difference of 6.5 degrees, P = 0.03). Similarly, in group II, the single staple produced a greater angulation than the 2 staples (difference 6 degrees, P = 0.08). When both groups were compared, no differences in the angulation produced by the 8-plate and the single staple with respect to the 2 staples were found. These results suggest that one of the reasons why the 8-plate may act in a more "physiological way" (vs. the traditional 2-staple or 3-staple hemiepiphysiodesis) could be the fact that the growth plate is tethered only at a single point. Therefore, the physis retains a major potential for growth and deformity. The 8-plate is superior in producing/correcting angular deformity when compared with the traditionally used staples (2 or more) but not when compared with a single staple.