Does Alignment in the Hindfoot Radiograph Influence Dynamic Foot-floor Pressures in Ankle and Tibiotalocalcaneal Fusion?

Abstract

Background The Saltzman-el-Khoury hindfoot alignment view (HAV) is considered the gold standard for assessing the axis from hindfoot to tibia. However, it is unclear whether radiographic alignment influences dynamic load distribution during gait. Questions/purposes We evaluated varus-valgus alignment by the HAV and its influence on dynamic load distribution in ankle and tibiotalocalcaneal (TTC) arthrodesis. Patients and Methods We clinically assessed 98 patients (ankle, 56; TTC, 42) with SF-36 and American Orthopaedic Foot and Ankle Society (AOFAS) scores, visual hindfoot alignment, HAV angle, and dynamic pedobarography using a five-step method. For comparison, 70 normal feet were evaluated. Minimum followup was 2 years (average, 4.11 years; range, 2-6 years). Results The mean HAV angle was À0.8°± 7.8°for ankle and À1.2°± 6.9°for TTC arthrodesis. The HAV angle correlated with pedobarographic load distribution (r = 0.35-0.53). Radiographic alignment did not influence SF-36 or AOFAS scores; however, load distribution correlated to qualities of these scores. Visual alignment only predicted the corresponding HAV angle in 48%. To reproduce the dynamic load of healthy subjects, HAV angles of 5°to 10°valgus were needed. Conclusions Visual positioning is inadequate to determine intraoperative positioning and resulted in a varus position with a relatively large SD. The HAV should be used to assess the hindfoot alignment correctly. HAV angles of 5°to 10°valgus are needed to reproduce a physiologic gait pattern.

Does the Subtalar Joint Compensate for Ankle Malalignment in End-stage Ankle Arthritis?

“…The moment arm of the calcaneus addresses mechanical alignment of the hindfoot by measurement of the apparent moment arm between the weightbearing axis of the lower leg and point of the heelfloor contact [25]. This method is reliable for assessment of coronal hindfoot alignment and for evaluation of mechanical hindfoot imbalance in patients before and after surgery [8,9]. In our study the moment arm of the calcaneus was the only parameter not significantly different (p = 0.203) in patients with end-stage ankle osteoarthritis from the control group, indicating that the subtalar joint generally compensated to achieve good hindfoot mechanical alignment.…”

“…Similarly, classification methods of hindfoot alignment remain controversial and are based mainly on clinical visual judgment or on radiographic measurement (eg, quantification of the tibiocalcaneal axis or the hindfoot ''apparent moment arm'') [8,9,21,25]. Clinical visual judgment of the hindfoot alignment may be incorrect, for example, owing to compensatory mechanisms of the hindfoot mimicking normal hindfoot alignment.…”

Three-dimensional hindfoot alignment measurements based on biplanar radiographs: comparison with standard radiographic measurements

“…The clinical assessment of hindfoot alignment and its radiographic quantification have gained considerable importance in the last few years, both for the initial assessment as well as for the postoperative monitoring of patients with various abnormalities of the foot and ankle [7,8,10,11]. A precise assessment of the hindfoot alignment is crucial in patients who undergo an ankle arthrodesis to plan the re-alignment of the hindfoot and to reproduce a physiologic gait pattern, or in patients with acquired flatfoot deformity where a tendon repair or tendon transfer is supplemented by a medial displacement calcaneal osteotomy [9, 10, 16].…”

“…We were able to show that 3D 11 hindfoot alignment measurements based on biplanar radiographs were substantially better than measuring the hindfoot alignment on the long axial view radiographs, thus making it easier to determine whether a hindfoot alignment is physiologic or whether it is abnormal. As a correct assessment of the hindfoot alignment is an important element in the treatment of various hindfoot or ankle abnormalities, 3D hindfoot alignment measurements could improve both the initial evaluation and planning of therapy in patients with conditions such as acquired flatfoot deformity or in patients that undergo ankle arthrodesis as well as for the assessment of the postoperative course in such patients [9,10,16]. Hindfoot alignment can be assessed with the biplanar x-ray scanner in an upright weightbearing position, which might be helpful for the quantification of hindfoot alignment when a decision needs to be made whether the hindfoot alignment is physiologic or abnormal and whether or not to perform a calcaneus osteotomy in a patient.…”

“…Hindfoot alignment is first estimated clinically during the physical examination, and is subsequently quantified on radiographs as a basis for treatment decisions, preoperative planning, and monitoring of the postoperative course [4][5][6][7][8][9][10]. The measurement of hindfoot alignment has been described on hindfoot alignment view radiographs (also called Cobey view) and long axial view radiographs [4].…”