The Unloading Effect of Supramalleolar Versus Sliding Calcaneal Osteotomy for Treatment of Osteochondral Lesions of the Medial Talus: A Biomechanical Study

BACKGROUND In patients with osteochondral lesion, defects of the medial talus, or failed cartilage surgery, a periarticular osteotomy can unload the medial compartment. PURPOSE To compare the effects of supramalleolar osteotomy (SMOT) versus sliding calcaneal osteotomy (SCO) for pressure redistribution and unloading of the medial ankle joint in normal, varus-aligned, and valgus-aligned distal tibiae. STUDY DESIGN Controlled laboratory study. METHODS Included were 8 cadaveric lower legs with verified neutral ankle alignment (lateral distal tibial angle [LDTA] = 0°) and hindfoot valgus within normal range (0°-10°). SMOT was performed to modify LDTA between 5° valgus, neutral, and 5° varus. In addition, a 10-mm lateral SCO was performed and tested in each position in random order. Axial loading (700 N) of the tibia was applied with the foot in neutral alignment in a customized testing frame. Pressure distribution in the ankle joint and subtalar joint, center of force, and contact area were recorded using high-resolution Tekscan pressure sensors. RESULTS At neutral tibial alignment, SCO unloaded the medial joint by a mean of 10% ± 10% or 66 ± 51 N (P = .04) compared with 6% ± 12% or 55 ± 72 N with SMOT to 5° valgus (P = .12). The achieved deload was not significantly different (ns) between techniques. In ankles with 5° varus alignment at baseline, SMOT to correct LDTA to neutral insufficiently addressed pressure redistribution and increased medial load by 6% ± 9% or 34 ± 33 N (ns). LDTA correction to 5° valgus (10° SMOT) unloaded the medial joint by 0.4% ± 14% or 20 ± 75 N (ns) compared with 9% ± 11% or 36 ± 45 N with SCO (ns). SCO was significantly superior to 5° SMOT (P = .017) but not 10° SMOT. The subtalar joint was affected by both SCO and SMOT, where SCO unloaded but SMOT loaded the medial side. CONCLUSION SCO reliably unloaded the medial compartment of the ankle joint for a neutral tibial axis. Changes in the LDTA by SMOT did not positively affect load distribution, especially in varus alignment. The subtalar joint was affected by SCO and SMOT in opposite ways, which should be considered in the treatment algorithm. CLINICAL RELEVANCE SCO may be considered a reliable option for beneficial load-shifting in ankles with neutral alignment or 5° varus malalignment

Talar neck angle correlates with tibial torsion-Guidance for 3D and 2D measurements in total ankle replacement

Axial plane alignment of the talar component in total ankle arthroplasty is poorly understood and remains a major issue, especially since malpositioning results in increased peak pressure and rotational torque. Further profound knowledge regarding individual anatomy of the talus and its relation to proximal and distal osseous structures is therefore needed. Therefore, three-dimensional (3D) surface models of 50 lower extremities were generated using computed tomography data of patients without ankle osteoarthritis. The talus neck torsion was measured using a novel 3D measurement method. Then, tibial torsion and subtalar joint axis orientation were measured and correlated to the talus neck torsion. Moreover, a 2D measurement method of the talus neck torsion was developed. A statistically significant correlation was found between external tibia torsion and medial talus neck torsion, as well as talus neck axis and subtalar joint axis in the transversal and frontal plane. The novel defined 3D measurement methods indicated excellent inter-rater and intra-rater reliability. The 2D measurement method of the talus neck torsion was in good agreement with the 3D method. The results showed that the rotational profiles of the tibia, talus, and adjacent joints are interconnected, which should be considered in total ankle replacement (TAR). Clinical relevance: This study improves the overall understanding of the talar anatomy, as well as its relationship to adjacent osseous structures. The novel 2D measurement method of the talus neck torsion might improve talar component positioning in the axial plane corresponding to the patient's individual anatomy, and therefore improve the survival rate of TAR

Talus morphology differs between flatfeet and controls, but its variety has no influence on extent of surgical deformity correction

BACKGROUND Progressive collapsing foot deformity (PCFD) is a complex 3-dimensional (3-D) deformity with varying degrees of hindfoot valgus, forefoot abduction, and midfoot varus. The first aim of this study was to perform a 3-D analysis of the talus morphology between symptomatic PCFD patients that underwent operative flatfoot correction and controls. The second aim was to investigate if there is an impact of individual talus morphology on the success of operative flatfoot correction. METHODS We reviewed all patients that underwent lateral calcaneal lengthening for correction of PCFD between 2008 and 2018 at our clinic. Radiographic flatfoot parameters on preoperative and postoperative radiographs were assessed. Additionally, 3-D surface models of the tali were generated using computed tomography (CT) data. The talus morphology of 44 flatfeet was compared to 3-D models of 50 controls without foot or ankle pain of any kind. RESULTS Groups were comparable regarding demographics. Talus morphology differed significantly between PCFD and controls in multiple aspects. There was a 2.6° increased plantar flexion (22.3° versus 26°; p = 0.02) and medial deviation (31.7° and 33.5°; p = 0.04) of the talar head in relation to the body in PCFD patients compared to controls. Moreover, PCFD were characterized by an increased valgus (difference of 4.6°; p = 0.01) alignment of the subtalar joint. Satisfactory correction was achieved in all cases, with an improvement of the talometatarsal-angle and the talonavicular uncoverage angle of 5.6° ± 9.7 (p = 0.02) and 9.9° ± 16.3 (p = 0.001), respectively. No statistically significant correlation was found between talus morphology and the correction achieved or loss of correction one year postoperatively. CONCLUSION The different morphological features mentioned above might be contributing or risk factors for progression to PCFD. However, despite the variety of talar morphology, which is different compared to controls, the surgical outcome of calcaneal lengthening osteotomy was not affected. LEVEL OF EVIDENCE III

Mid- to Long-Term Results of Total Ankle Replacement in Patients with Hemophilic Arthropathy

Category: Ankle Arthritis Introduction/Purpose: Hemophilia is a rare hematological disease associated with spontaneous joint hemorrhaging causing hemophilic arthropathy. Symptoms comprise joint pain and deformity, paired with loss of function. In the presence of advanced joint deterioration, therapeutic options are confined to either arthroplasty or arthrodesis. For the ankle, the latter is still referred to as the procedure of choice. However - in light of its capacity to reduce pain while preserving ankle motion - total ankle replacement (TAR) has recently gained acceptance as an alternative. The aim of this study was to investigate the mid- to long-term results of TAR in hemophilic ankle arthropathy. Methods: Seventeen TARs were implanted between 1998 and 2012 (mean age: 43 years). Preoperative demographic and disease specific data, complications and revision surgeries were recorded. With a mean follow-up of 9.3 years (range, 2.2-17.8) implant survival was estimated using Kaplan-Meier analysis. Follow-up assessment of 12 TARs was performed after 9.6 years (5 lost to follow-up). Satisfaction and pain scales, the AOFAS hindfoot-score, and the SF-36 were obtained to assess clinical outcome. Radiographic evaluation of pre- and follow-up radiographs was conducted. Results: Three cases (17.6%) had undergone TAR removal secondary to loosening at an average interval of 7.5 years. The estimated implant survival was 94% at 5, 85% at 10, and 70% at 15 years (95% CI, 11.9-17.7). The mean estimated implant survival was 14.77 years (95% CI, 11.9-17.7). The mean level of satisfaction was 76%, and of pain 2/10 (VAS). ROM had increased significantly (p=0.037). The SF-36 summary scores were comparable to those of a matched standard population. The AOFAS hindfoot-score averaged 81/100 points. Conclusion: TAR is a viable treatment option for advanced hemophilic ankle arthropathy. Based on the herein presented follow- up, implant survival compares to that of non-hemophilic populations. Clinical mid- to long-term results are favorable. However, the majority of follow-up radiographs revealed component loosening and/or periprosthetic lucency. Considering the study population’s young age and specific risk factors, need for revision surgery secondary to symptomatic component loosening may arise

The Unloading Effect of Supramalleolar Versus Sliding Calcaneal Osteotomy for Treatment of Osteochondral Lesions of the Medial Talus: A Biomechanical Study

Background:In patients with osteochondral lesion, defects of the medial talus, or failed cartilage surgery, a periarticular osteotomy can unload the medial compartment.Purpose:To compare the effects of supramalleolar osteotomy (SMOT) versus sliding calcaneal osteotomy (SCO) for pressure redistribution and unloading of the medial ankle joint in normal, varus-aligned, and valgus-aligned distal tibiae.Study Design:Controlled laboratory study.Methods:Included were 8 cadaveric lower legs with verified neutral ankle alignment (lateral distal tibial angle [LDTA] = 0 degrees) and hindfoot valgus within normal range (0 degrees-10 degrees). SMOT was performed to modify LDTA between 5 degrees valgus, neutral, and 5 degrees varus. In addition, a 10-mm lateral SCO was performed and tested in each position in random order. Axial loading (700 N) of the tibia was applied with the foot in neutral alignment in a customized testing frame. Pressure distribution in the ankle joint and subtalar joint, center of force, and contact area were recorded using high-resolution Tekscan pressure sensors.Results:At neutral tibial alignment, SCO unloaded the medial joint by a mean of 10% +/- 10% or 66 +/- 51 N (P = .04) compared with 6% +/- 12% or 55 +/- 72 N with SMOT to 5 degrees valgus (P = .12). The achieved deload was not significantly different (ns) between techniques. In ankles with 5 degrees varus alignment at baseline, SMOT to correct LDTA to neutral insufficiently addressed pressure redistribution and increased medial load by 6% +/- 9% or 34 +/- 33 N (ns). LDTA correction to 5 degrees valgus (10 degrees SMOT) unloaded the medial joint by 0.4% +/- 14% or 20 +/- 75 N (ns) compared with 9% +/- 11% or 36 +/- 45 N with SCO (ns). SCO was significantly superior to 5 degrees SMOT (P = .017) but not 10 degrees SMOT. The subtalar joint was affected by both SCO and SMOT, where SCO unloaded but SMOT loaded the medial side.Conclusion:SCO reliably unloaded the medial compartment of the ankle joint for a neutral tibial axis. Changes in the LDTA by SMOT did not positively affect load distribution, especially in varus alignment. The subtalar joint was affected by SCO and SMOT in opposite ways, which should be considered in the treatment algorithm.Clinical Relevance:SCO may be considered a reliable option for beneficial load-shifting in ankles with neutral alignment or 5 degrees varus malalignment.ISSN:2325-967