The role of medial ligaments and tibialis posterior in stabilising the medial longitudinal foot arch: a cadaveric gait simulator study

Association between clinical and MRI-detected imaging findings for people with midfoot pain, a cross-sectional study

BACKGROUND

Midfoot pain is common but poorly understood, with radiographs often indicating no anomalies. This study aimed to describe bone, joint and soft tissue changes and to explore associations between MRI-detected abnormalities and clinical symptoms (pain and disability) in a group of adults with midfoot pain, but who were radiographically negative for osteoarthritis.

METHODS

Community-based participants with midfoot pain underwent an MRI scan of one foot and scored semi-quantitatively using the Foot OsteoArthritis MRI Score (FOAMRIS). Foot pain and disability were recorded using visual analog scales (VAS) and the Modified-Manchester Foot Pain Disability Index (MMFPDI). Associations were assessed for continuous data using Spearman's Rho, and for categorical data, a Wilcoxon signed rank test. Linear regression was used to explore the association between participant-reported measures and MRI abnormalities, adjusted for age, sex and BMI.

RESULTS

Sixty-one participants (70% female, mean age 48.5 years, median BMI 28.6 kg/m2) were included. Median VAS pain was 31/100 mm (IQR 21-47) and median disability was 30/48 (IQR 26-36). There was a moderate association between midfoot pain severity and the number of joints exhibiting joint space narrowing; adjusted results suggested 31% (95% confidence interval 3%-68%) worse VAS pain with each additional affected joint. Greater numbers of joints with cysts were associated with worse VAS pain [14% (0%-31%)] and disability [1.1 units (0-2.2)]. Effusion/synovitis was associated with MMFPDI pain. No other MRI abnormalities were associated with sex, body mass and foot pain/disability measures. Bone marrow lesions, joint space narrowing, cysts and osteophytes occurred more frequently with age. MRI abnormalities were common, particularly in the talo-navicular joint, first and second cuneo-metatarsal joints. Those with dorsal foot pain had more multi-joint involvement, bone marrow lesions, joint space narrowing and cysts and for those with pain on midfoot movement, bone marrow lesions and cysts were reported.

CONCLUSIONS

In people with midfoot pain, MRI-detected features of osteoarthritis and soft-tissue abnormalities were found, clustered in the medial and intermediate cuneiform joints. These features were more common with age but not associated with pain or disability measures. Younger people with dorsal midfoot pain exhibited early signs of bone and joint features of osteoarthritis and we recommend further imaging studies to determine the clinical and diagnostic significance.

Review of Classification Systems for Adult Acquired Flatfoot Deformity/Progressive Collapsing Foot Deformity and the Novel Development of the Triple Classification Delinking Instability/Deformity/Reactivity and Foot Type

Background: Classifications of AAFD/PCFD have evolved with an increased understanding of the pathology involved. A review of classification systems helps identify deficiencies and respective contributions to the evolution in understanding the classification of AAFD/PCFD. Methods: Using multiple electronic database searches (Medline, PubMed) and Google search, original papers classifying AAFD/PCFD were identified. Nine original papers were identified that met the inclusion criteria. Results: Johnson's original classification and multiple variants provided a significant leap in understanding and communicating the pathology but remained tibialis posterior tendon-focused. Drawbacks of these classifications include the implication of causality, linearity of progression through stages, an oversimplification of stage 2 deformity, and a failure to understand that multiple tendons react, not just tibialis posterior. Later classifications, such as the PCFD classification, are deformity-centric. Early ligament laxity/instability in normal attitude feet and all stages of cavus feet can present with pain and instability with minor/no deformity. These may not be captured in deformity-based classifications. The authors developed the 'Triple Classification' (TC) understanding that primary pathology is a progressive ligament failure/laxity that presents as tendon reactivity, deformity, and painful impingement, variably manifested depending on starting foot morphology. In this classification, starting foot morphology is typed, ligament laxities are staged, and deformity is zoned. Conclusions: This review has used identified deficiencies within classification systems for AAFD/PCFD to delink ligament laxity, deformity, and foot type and develop the 'Triple classification'. Advantages of the TC may include representing foot types with no deformity, defining complex secondary instabilities, delinking foot types, tendon reactivity/ligament instability, and deformity to represent these independently in a new classification system. Level of Evidence: Level V.

Ligament Insufficiency with Flatfoot: Spring Ligament and Deltoid Ligament

The objective of this article was to review the deltoid ligament and spring ligament specifically as they pertain to ligament insufficiency and adult-acquired flatfoot deformity. Discussion includes the normal and abnormal biomechanical forces that extend through these ligaments in normal and flatfoot deformity. Current literature related to spring ligament repair as part of the flatfoot deformity reconstruction is also reviewed.