Martin Haan

Co-authors: L. Blankevoort, K.T. Lambers, R. Blom, I.N. Sierevelt, G. Tuijthof, G.M.M.J. Kerkhoffs, J.N. Doornberg

Dynamic Computed-Tomographic Assessment of the Ankle Syndesmosis: Reliability of Imaging Technique

Recent studies on fixation of syndesmotic injuries associated with rotational type ankle fractures suggest that the clinical paradigm may be shifting towards dynamic fixation of the ankle syndesmosis. However, knowledge of dynamic properties of the syndesmosis in vivo is limited. The objective of this study is to evaluate the reliability of dynamic –in vivo– computed-tomography (CT) assessment of the ankle syndesmosis. Patients: Twelve subjects with a clinical history of ankle instability, but without suspected syndesmotic injury. Intervention: CT-scans of one ankle in neutral and four extreme positions (dorsiflexion with/without eversion, plantarflexion with/without inversion) using a CT-compatible loading platform. Custom axial slices were created from each scan. Main outcome measures: Previously validated CT-measurements were used to quantify the geometric dimensions of the syndesmosis in the various positions: length of the incisura (LI), fibular length (FL), sagittal translation of the fibula (ST), tibiofibular clear space (TFCS), anterior/posterior widths of the syndesmosis (AW, PW) and fibular orientation. Statistical analysis: Intra- and inter-observer reliability was calculated using intraclass correlation-coefficient (ICC). Additionally, smallest detectable change (SDC; minimal displacement that ensures displacement is not result of measurement error) was calculated. Results: All measurements revealed excellent intra-observer ICC (range 0.89-0.98). Inter-observer ICCs were good to excellent (range 0.63-0.97). Upon ankle movement, CT- measurements showed significant displacement from neutral position to each extreme position (ΔTFCS, ΔST, ΔTFCS, ΔAW, ΔPW), all larger than their respective SDCs. Conclusions: Dynamic CT assessment and quantification of motion in the horizontal plane of the ankle syndesmosis is a clinically reliable technique.

TEUN TEUNIS - Published in 'J Hand Microsurg' in press

Co-authors: N.H. Bosma, B. Lubberts, D. Ter Meulen, D. Ring

3D quantification of intra-articular distal radius fracture fragment displacement

We developed a method using quantitative 3D computed tomography (Q3DCT) to measure displacement of each individual fracture fragment in 3D space, the fragment’s surface area, and surface area of the gap between fracture fragments. Applying this technique to 50 AO type C distal radius fractures showed that radial styloid fragments were most displaced, and volar lunate fragments were least displaced. Volar lunate fragments had the largest articular surface area. While these findings confirm Melone’s concepts, the finding that volar lunate fragments are relatively large and dorsal lunate fragments relatively small suggests that alignment of the volar lunate fragment with the radial styloid may be the key element of surgical treatment. The dorsal lunate fragment may not routinely benefit from specific reduction and fixation. Q3DCT could study this when combined with PROMs.

Lukas Mangnus - Published in 'J Orthop Trauma' 2015

Co-authors: D.T. Meijer, S.A. Stufkens, J.J. Mellema, E.Ph. Steller, G.M.M.J. Kerkhoffs, J.N. Doornberg

Posterior malleolar fracture patterns

We studied the morphology of posterior malleolar fractures using Cole fracture mapping and assessed the reliability of Q3DCT–modeling with respect to quantification of fragment size (in cubic millimeter) and true articular involvement (in square millimeter). CT scans of a consecutive series of 45 patients with an ankle fracture involving the posterior malleolus were reconstructed to calculate (1) fracture maps, (2) fragment volume, (3) articular surface of the posterior malleolar fragment, (4) articular surface of intact tibia, and (5) articular surface of the medial malleolus by 3 independent observers. Fracture mapping revealed (1) a continuous spectrum of posterolateral oriented fracture lines and (2) fragments with posterolateral to posteromedial oriented fracture lines extending into the medial malleolus. Reliability of measurements of the volume and articular surface of posterior malleolar fracture fragments was defined as almost perfect according to the categorical system of Landis. We can conclude that mapping of posterior malleolar fractures revealed a continuous spectrum of Haraguchi III to I fractures and identified Haraguchi type II as a separate pattern. Q3DCT–modeling is reliable to assess fracture characteristics of posterior malleolar fracture fragments. Morphology might be more important than posterior malleolar fracture size alone for clinical decision making.