Assessment of Progressive Collapsing Foot Deformity Using Semiautomated 3D Measurements Derived From Weightbearing CT Scans

Krähenbühl, Nicola; Kvarda, Peter; Susdorf, Roman; Burssens, Arne; Ruiz, Roxa; Barg, Alexej; Hintermann, Beat

doi:10.1177/10711007211049754

Cited by 29 publications

(48 citation statements)

References 37 publications

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“…Is it only limited to the subtalar articulations, or could it be reflected in other peritalar joints such as talonavicular joint uncovering in class B or hindfoot valgus in class A? 13 Should the term peritalar subluxation be based on CT scans, plain radiographs, a clinical diagnosis such as subfibular impingement, or a combination of the above? Unfortunately, this is poorly defined in the PCFD classification, which states “significant subtalar joint subluxation/subfibular impingement.” What is the range for a case to be considered as significant and how should it be diagnosed?…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Accuracy of the Progressive Collapsing Foot Deformity (PCFD) Classification

Zhu

et al. 2022

Foot Ankle Int.

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Background: A consensus group recently proposed the term progressive collapsing foot deformity (PCFD) and a new classification with 2 stages plus 5 classes to describe the complex array of flatfoot deformities. This study aimed to validate different diagnostic accuracy rates of the PCFD classification. Methods: This was a survey-based study distributed among 13 foot and ankle fellowship programs for 3 groups of participants with varied experience in practice (group 1: fellows in training, group 2: surgeons in practice for 1-4 years, and group 3: surgeons in practice for ≥5 years). Each participant was asked to assign 20 different cases of flatfoot deformity to the appropriate classes and stages using the PCFD classification. The overall diagnostic accuracy, class, and stage diagnostic accuracy rates for the 20 cases were calculated first for the entire cohort and then compared among the 3 groups. The misdiagnosis rate for each class of deformity (the sum of overdiagnosis and underdiagnosis rates) of the entire cohort was calculated and compared with the other classes. Mean and standard evidence were used to describe numerical data. One-way analysis of variance was used to compare values among the 3 groups and the 5 classes. P <.05 was considered statistically significant. Results: For the whole cohort, the overall diagnostic accuracy, class diagnostic accuracy, and stage diagnostic accuracy rates were 71.0%, 78.3%, and 81.7%, respectively There was a statistically significant difference between group 1 and 2, and group 1 and 3, in overall diagnostic accuracy and class diagnostic accuracy, with no significant difference among the 3 groups regarding stage diagnostic accuracy. Class B had a significantly higher overdiagnosis rate than the rest of the classes, whereas class D was significantly underdiagnosed than others. The misdiagnosis rates for classes A to E were 3.3%, 17.5%, 11.1%, 26.0%, and 3.7%, respectively. Conclusion: The PCFD classification showed overall fair diagnostic accuracy rates. The highest diagnostic accuracy was for “hindfoot valgus deformity” and “ankle instability.” Further content validation of the PCFD classification is needed to examine the terminology and interpretation of those classes with low diagnostic accuracy including “midfoot/forefoot abduction deformity,” “forefoot varus deformity/medial column instability,” and “peritalar subluxation/dislocation.” Level of Evidence: Level II, prospective comparative study.

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Section: Discussionmentioning

confidence: 99%

Diagnostic Accuracy of the Progressive Collapsing Foot Deformity (PCFD) Classification

Zhu

et al. 2022

Foot Ankle Int.

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“…Weightbearing computed tomography could possibly be implemented to improve our understanding of the effect of supramalleolar osteotomy on hindfoot mechanics. 1,6,22…”

Section: Discussionmentioning

confidence: 99%

Supramalleolar Lateral Opening-Wedge Osteotomy in Conjunction With Progressive Collapsing Foot Deformity Reconstruction for PCFD With Ankle Instability

et al. 2022

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Background: Reconstruction of progressive collapsing foot deformity (PCFD) with ankle instability (PCFD class E) remains a substantial challenge to orthopaedic surgeons. We report the outcomes of PCFD class E treated by means of a relatively standard PCFD foot reconstruction approach with the addition of a supramalleolar lateral opening-wedge osteotomy. Methods: We conducted a retrospective study of 13 patients (15 ankles) who underwent this procedure for PCFD class E between 2010 and 2021. Mean follow-up time was 3.8 (range, 2-6.3) years. Clinical assessment was based on the Japanese Society for Surgery of the Foot (JSSF) ankle/hindfoot scale as well as a Self-Administered Foot Evaluation Questionnaire (SAFE-Q). Radiographic assessments, including identification of the mechanical ankle joint axis point and a modified valgus Takakura-Tanaka osteoarthritis grade, were recorded. Results: The mean JSSF score improved significantly from 45.2 preoperatively to 83.9 postoperatively ( P < .001). SAFE-Q scores at the final follow-up were 70.1 for the pain and pain-related subscale, 75.4 for the physical functioning and daily living subscale, 83.0 for the social functioning subscale, 74.4 for the shoe-related subscale, and 78.1 for the general health and well-being subscale. Radiographic measurements showed improvement in the tibiotalar tilt angle (average improvement: 5.4 degrees); orientation of the talus joint line relative to the ground (average improvement: 14.0 degrees); anteroposterior talus–first metatarsal angle (average improvement: 11.2 degrees), talonavicular coverage angle (average improvement: 21.6 degrees), and lateral talus–first metatarsal angle (average improvement: 17.0 degrees). Postoperatively, the mechanical ankle joint axis point moved medially for all patients and into the medial half of the ankle joint for 7 patients. The modified osteoarthritis stage improved postoperatively in most cases. Conclusion: In this select and relatively small group of patients who had a supramalleolar lateral opening-wedge osteotomy combined with PCFD reconstruction, we measured general improvement in JSSF scores and radiographic variables. Long-term durability of the procedure remains unknown. This procedure may be an option for preserving the ankle joint in treatment of PCFD class E with osteoarthritis of the ankle. Level of Evidence: Level IV, therapeutic.

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“…Previous studies reporting these computed measurements derived from 3-dimensional isosurfaces using the same or other software have demonstrated a high intra- and interobserver reliability for angular measurements used in this study. 10,32,36,37 One study in particular used the same software to obtain automated 3-dimensional measurements in patients with ankle osteoarthritis. 36 Reported ICCs for interobserver reliability ranged from 0.97 to 0.99 and ICCs for intraobserver reliability ranged between 0.91 and 0.99.…”

Section: Methodsmentioning

confidence: 99%

“…These reports demonstrated a high reliability for previously described radiographic parameters in both ankle osteoarthritis and progressive collapsing foot deformity, with a reduction of the time spent to generate these 3-dimensional measurements. 32,36,37,47 Despite these technological advances, we could not identify previous studies in the field of foot and ankle surgery that had implemented automated measurements to perform a pre- vs postoperative comparison. Moreover, the use of these 3-dimensional measurements in ankle varus deformities could potentially elucidate the complex configuration of the subtalar joint before and after supramalleolar osteotomy.…”

Section: Introductionmentioning

confidence: 99%

Supramalleolar Osteotomy for Ankle Varus Deformity Alters Subtalar Joint Alignment

et al. 2022

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Background: Although correction of ankle and hindfoot deformity after supramalleolar osteotomy has been investigated extensively, the specific effect on the subtalar joint alignment remains elusive. This can be attributed to the limitations of 2-dimensional measurements, which impede an exact quantification of the 3-dimensional subtalar joint alignment. Therefore, we determined both the ankle, hindfoot, and subtalar joint alignment before and after supramalleolar osteotomy using autogenerated 3-dimensional measurements based on weightbearing CT imaging. Methods: Twenty-nine patients with a mean age of 50.4±10.6 years were retrospectively analyzed in a pre-post study design using weightbearing CT. Inclusion criteria were correction of ankle varus deformity by an opening wedge (n = 22) or dome osteotomy (n = 7). Exclusion criteria consisted of an additional inframalleolar arthrodesis or osteotomy. Corresponding 3-dimensional bone models were reconstructed to compute following autogenerated measurements of the ankle- and hindfoot alignment: tibial anterior surface (TAS), tibiotalar surface (TTS), talar tilt (TT) angle, hindfoot angle (HA). In addition, the talocalcaneal angle (TCA) in the axial (TCAax), sagittal (TCAsag), and coronal (TCAcor) plane were measured to assess the subtalar joint alignment. Results: The preoperative radiographic parameters of the ankle joint alignment (TAS=88±4 degrees, TTS=82±7 degrees, TT=5.8±4.9 degrees) improved significantly relative to their postoperative equivalents (TAS = 93±5 degrees, TTS = 88±7 degrees, TT=4.2±4.5 degrees; P < .05). The following radiographic parameters of the hindfoot and subtalar joint alignment improved significantly from preoperatively (8.7±8.9 degrees, TCAax = 41±10 degrees, TCAsag = 48±10 degrees) to postoperatively (HA=4.5±8.6 degrees, TCAax = 38±9 degrees, TCAsag = 44±11 degrees; P < .05). No significant differences could be detected in the coronal plane alignment of the subtalar joint (TCAcor) pre- compared to postoperatively ( P > .05). Conclusion: This study quantified the 3-dimensional ankle, hindfoot, and subtalar joint alignment after a solitary supramalleolar osteotomy. We found alterations in the subtalar joint alignment, which occurred by 2 to 3 degrees in each anatomic plane. However, before recommendations can be given related to inframalleolar procedures in conjunction to supramalleolar osteotomies, further studies on the variation of subtalar joint alignment change are needed.

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Assessment of Progressive Collapsing Foot Deformity Using Semiautomated 3D Measurements Derived From Weightbearing CT Scans

Cited by 29 publications

References 37 publications

Diagnostic Accuracy of the Progressive Collapsing Foot Deformity (PCFD) Classification

Diagnostic Accuracy of the Progressive Collapsing Foot Deformity (PCFD) Classification

Supramalleolar Lateral Opening-Wedge Osteotomy in Conjunction With Progressive Collapsing Foot Deformity Reconstruction for PCFD With Ankle Instability

Supramalleolar Osteotomy for Ankle Varus Deformity Alters Subtalar Joint Alignment

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