Comparing First Metatarsophalangeal Joint Flexibility in Hallux Rigidus Patients Pre- and Postcheilectomy Using a Novel Flexibility Device.

BACKGROUND: Hallux rigidus (HR) is a common pathology of the first metatarsophalangeal (MTP) joint causing pain and stiffness. However, severity of symptoms and radiographic findings are not always concordant. A novel flexibility device, which measures the mobility of the MTP joint through its arc of motion, has been validated. This study compares flexibility in patients before and after cheilectomy (with or without proximal phalanx osteotomy) for HR. METHODS: This is a single-center study of adult patients with HR who were indicated for cheilectomy or cheilectomy and Moberg (dorsiflexion closing wedge) osteotomy of the proximal phalanx based on symptoms and radiographs from 2013 to 2015. Pre- and postoperatively, patients underwent testing with a validated flexibility protocol to generate flexibility curves. Parameters included early and late flexibility, laxity torque, and laxity angle. Patients completed Foot and Ankle Outcomes Scores (FAOS) pre- and postoperatively. Twelve operative patients underwent preoperative testing, with 9 completing postoperative testing (mean age, 53.0 years; 67% female; mean 2.8-year follow-up). RESULTS: Patients had significant improvements in early sitting and standing flexibility, sitting and standing laxity angles, standing laxity torque, and both sitting and standing maximum dorsiflexion after surgery (all P < .05). While preoperative early flexibility, laxity angle, and maximum dorsiflexion all differed significantly between patients and controls (P < .015), postoperative early flexibility was similar to controls (P > .279). FAOS scores for pain, symptoms, sport, and quality improved significantly after surgery. CONCLUSION: Surgical treatment with cheilectomy was associated with significant improvements in nearly all flexibility parameters for sitting and standing positions. However, most postoperative flexibility parameters did not improve to the level of normal controls. Regardless, patients still experienced significant improvements in outcomes. This study demonstrated that surgical correction is associated with significant biomechanical and clinical results. The flexibility device can be used in further studies to assess outcomes after other HR procedures. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Imaging of Bone Perfusion and Metabolism in Subjects Undergoing Total Ankle Arthroplasty Using 18F-Fluoride Positron Emission Tomography.

BACKGROUND: Total ankle arthroplasty (TAA) continues to exhibit a relatively high incidence of complications and need for revision surgery compared to knee and hip arthroplasty. One common mode of failure in TAA is talar component subsidence. This may be caused by disruption in the talar blood supply related to the operative technique. The purpose of this study was to quantify changes in talar bone perfusion and turnover before and after TAA with the INBONE II system using 18F-fluoride positron emission tomography / computed tomography (PET/CT). METHODS: Nine subjects (5 M/4 F) aged 68.9 ± 8.2 years were enrolled for 18F-fluoride PET/CT imaging before and 3 months after TAA. Regions of interest (ROI) were placed on the postoperative CT images in the body of the talus beneath the talar component and overlaid on the fused static PET images. Standard uptake values (SUVs) along with dynamic K1 (bone blood flow) and ki (bone metabolism or osteoblastic turnover) were calculated. RESULTS: The SUV underneath the talar component compared to that measured at baseline before surgery was 1.93 ± 0.29 preoperatively vs 2.47 ± 0.37 postoperatively (P > .05). K1 was 0.84 ± 0.16 mL/min/mL preoperatively vs 1.51 ± 0.23 mL/min/mL postoperatively (P = .026). ki was constant at 0.09 ± 0.03 mL/min/mL preoperatively vs 0.12 ± 0.03 mL/min/mL postoperatively (P > .05). CONCLUSION: Our study was the first to link 18F-fluoride PET/CT with pre-post evaluation of total ankle replacements. The study quantified perfusion within the talus beneath the TAA implant supporting the hypothesis that perfusion of the talus remained intact after surgery. LEVEL OF EVIDENCE: Level II, prospective cohort study with development of diagnostic criteria.

Comparison of Tibial and Talar Bone Density in Patients Undergoing Total Ankle Replacement vs Non-Ankle Arthritis Matched Controls.

BACKGROUND: Bone quality in the distal tibia and talus is an important factor contributing to initial component stability in total ankle replacement (TAR). However, the effect of ankle arthritis on bone density in the tibia and talus remains unclear. The objective of this study was to compare bone density of tibia and talus in arthritic and nonarthritic ankles as a function of distance from ankle joint. METHODS: We retrospectively reviewed 93 end-stage ankle arthritis patients who had preoperative nonweightbearing ankle computed tomography (CT) and identified a cohort of 83 nonarthritic ankle patients as a demographic-matched control group. A region of interest tool was used to calculate Hounsfield unit (HU) values in the cancellous region of the tibia and talus. Measurements were obtained on axial cut CTs from 6 to 12 mm above the tibial plafond, and 1 to 4 mm below the talar dome. HU measurements between groups and the decrease of HU at the relative level in each group were compared. RESULTS: Arthritic ankles demonstrated significantly greater mean bone density than nonarthritic ankles at between 6 and 10 mm above the joint in the tibia (P < .05). No significant difference in bone density between 10 and 12 mm from the joint in the tibia nor at any level of the talus was found between groups. In both groups, bone density decreased significantly at each successive level away from the ankle joint. CONCLUSION: Ankle arthritis patients demonstrated greater or equal bone density in both the tibia and talus compared to demographic-matched controls. In both groups, bone density decreased with increasing distance away from the articular surface. In TAR, tibial bone resection between 6 and 8 mm may provide improved initial implant stability. LEVEL OF EVIDENCE: Level III, comparative study.