Hindfoot alignment at one year after total knee arthroplasty

Abstract

PurposeIt has previously been found that valgus hindfoot alignment (HFA) improves 3 weeks following total knee arthroplasty (TKA) for varus knee osteoarthritis (OA). In the present study, HFA was evaluated prior to TKA, as well as 3 weeks and 1 year following TKA. Using these multiple evaluations, the chronological effects of TKA on HFA were investigated.MethodsThe study included 71 patients (73 legs) who underwent TKA for varus knee OA. Radiograph examinations of the entire limb and hindfoot were performed in the standing position prior to TKA, as well as 3 weeks and 1 year following TKA. The varus–valgus angle was used as an indicator of HFA in the coronal plane. Patients were divided into two groups according to the preoperative varus–valgus angle: a hindfoot varus group (varus–valgus angle <76°) and a hindfoot valgus group (varus–valgus angle ≥76°). The changes in the varus–valgus angle were evaluated and compared in both groups.ResultsIn the hindfoot valgus group, the mean ± standard deviation varus–valgus angle significantly declined from 80.5 ± 3.1° prior to TKA to 78.6 ± 3.7° 3 weeks following TKA and 77.1 ± 2.7° 1 year following TKA. However, in the hindfoot varus group, the mean varus–valgus angle prior to TKA (72.7 ± 2.6°) did not differ significantly from the mean varus–valgus angles 3 weeks (72.3 ± 3.3°) or 1 year (73.5 ± 3.0°) following TKA.ConclusionsHFA improved chronologically in legs with hindfoot valgus as a result of the alignment compensation ability of the hindfoot following TKA. However, no improvement was noted in legs with hindfoot varus because the alignment compensation ability of the hindfoot had been lost. The patients with hindfoot varus should be attended for ankle pain in the outpatient clinic after TKA.Level of evidenceIII.

3D Biometrics for Hindfoot Alignment Using Weightbearing CT

“…7,[27][28][29]41 HFA measures based on 2D radiographs are flawed by many anatomical and operator-related bias, which have been extensively investigated in the literature. * These include projection and rotational issues, 3,22 mostly with regards to the use of the tibia as a reference axis.…”

Ankle and Hindfoot Symptoms after Medial Open Wedge High Tibial Osteotomy

“…2 If the ankle and subtalar joints are supple, they may reorient themselves after knee deformity has been corrected as after TKA. 1,2 However, inability of these joints to completely reorient themselves after knee realignment may predispose to foot or ankle symptoms. 1,2,5 We feel this may have predisposed to ankle and hindfoot symptoms in the symptomatic group in our study.…”

“…Several authors have suggested a cautious follow-up of patients for ankle or foot symptoms following TKA especially if they have a stiff subtalar joint preoperatively. 1,2,7 It is intuitive to believe that a large change in TPI would necessitate a proportionately large change in subtalar joint orientation to maintain neutral lower limb alignment. This is likely to place large stresses across the subtalar joint especially if it is stiff.…”

The subtalar joint

“…Several authors also investigated the hindfoot alignment in patients with knee osteoarthritis. 66 - 69 Interestingly, patients with valgus knee osteoarthritis tend to a varus hindfoot alignment and vice versa . 68 …”