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

Abstract

Background Patients with ankle arthritis often present with concomitant hindfoot deformity, which may involve the tibiotalar and subtalar joints. However, the possible compensatory mechanisms of these two mechanically linked joints are not well known. Questions/purposes In this study we sought to (1) compare ankle and hindfoot alignment of our study cohort with end-stage ankle arthritis with that of a control group; (2) explore the frequency of compensated malalignment between the tibiotalar and subtalar joints in our study cohort; and (3) assess the intraobserver and interobserver reliability of classification methods of hindfoot alignment used in this study. Methods Between March 2006 and September 2013, we performed 419 ankle arthrodesis and ankle replacements (380 patients). In this study, we evaluated radiographs for 233 (56%) ankles (226 patients) which met the following inclusion criteria: (1) no prior subtalar arthrodesis; (2) no previously failed total ankle replacement or ankle arthrodesis; (3) with complete conventional radiographs (all three ankle views were required: mortise, lateral, and hindfoot alignment view). Ankle and hindfoot alignment was assessed by measurement of the medial distal tibial angle, tibial talar surface angle, talar tilting angle, tibiocalcaneal axis angle, and moment arm of calcaneus. The obtained values were compared with those observed in the control group of 60 ankles from 60 people. Only those without obvious degenerative changes of the tibiotalar and subtalar joints and without previous surgeries of the ankle or hindfoot were included in the control group. Demographic data for the patients with arthritis and the control group were comparable (sex, p = 0.321; age, p = 0.087). The frequency of compensated malalignment between the tibiotalar and subtalar joints, defined as tibiocalcaneal angle or moment arm of the calcaneus being greater or smaller than the same 95% CI statistical cutoffs from the control group, was tallied. All ankle radiographs were independently measured by two observers to determine the interobserver reliability. One of Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangement etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. This ...

New Technique for Tibiotalar Arthrodesis Using a New Intramedullary Nail Device: A Cadaveric Study

“…Our intramedullary device combines the stiffness of intramedullary nail devices, while still using a minimally invasive approach, and obviates the need for a secondary surgery associated with the use of external fixation. Our new intramedullary device improves on the TTC nail by sparing the subtalar joint, which has been proposed to allow for compensation of the malalignment associated with worsening tibiotalar arthritis, and thus its importance cannot be overlooked [9]. When compared to traditional open approaches and the use of screws and plates our technique and device have less periosteal stripping.…”

Influence of Ankle Position and Radiographic Projection Angle on Measurement of Supramalleolar Alignment on the Anteroposterior and Hindfoot Alignment Views

“…5,6,26,28 The MDTA is widely used to determine the amount and orientation of these supramalleolar deformities. 4,10,22,27,38,39,49,56 Incorrect assessment of the MDTA may result in under-or overcorrection that is associated with reduced outcomes following surgery. 5,6 Our study did not establish superiority of a single view to assess supramalleolar alignment.…”

“…In clinical practice, the MDTA is most often measured from an AP projection with 20 degrees of internal rotation of the foot (ie, mortise view). 4,27,38,49,56 We advocate for continued use of the mortise view, but given the finding that the MDTA on the AP view was sensitive to tilt of the x-ray beam, we would also recommend that technicians and clinicians adopt strategies to ensure that the beam is aligned directly with the horizon. This could be accomplished by resting the x-ray equipment on a flat, horizontal surface with the foot elevated at the correct height.…”

“…46,52,56 Concomitant varus or valgus deformities frequently accompany cartilage damage in osteoarthritic ankles. 19,20 Surgical strategies to treat OA address both cartilage damage and possible malalignment.…”

Commentary on the paper: “Hindfoot malalignment in adults with haemophilic ankle arthropathy: The importance of early detection and orthotic treatment”

“…Patients with post‐traumatic ankle osteoarthritis often present with a concomitant hindfoot deformity . In 2015, we analysed weightbearing radiographs of 226 patients with end‐stage, symptomatic ankle osteoarthritis and demonstrated that only 64.4% of all patients had a hindfoot alignment within normal range . Patients with concomitant ankle deformity – valgus or varus – and asymmetric ankle joint load may be vulnerable to asymmetric, premature cartilage damage.…”