Midfoot osteoarthritis (OA) is a common condition, however its aetiology is not well understood. Understanding how plantar pressures differ between people with and without midfoot OA may provide insight into the aetiology and how best to manage this condition.
To compare plantar pressures between people with and without symptomatic radiographic midfoot OA.
This was a cross-sectional study of adults aged ≥ 50 years registered with four UK general practices who reported foot pain in the past year. Symptomatic radiographic midfoot OA was defined as midfoot pain in the last four weeks, combined with radiographic OA in one or more midfoot joints. Cases were matched 1:1 for sex and age ( ± 5 years) to controls. Peak plantar pressure and maximum force in 10 regions of the foot were determined using a pressure platform (RSscan International, Olen, Belgium) and compared between the groups using independent samples t-tests and effect sizes (Cohen\'s d).
We included 61 midfoot OA cases (mean age 67.0, SD 8.1, 31 males, 30 females) and matched these to 61 controls (mean age 66.0, SD 7.9). Midfoot OA cases displayed greater force (d=0.79, medium effect size, p = <0.001) and pressure at the midfoot (d=0.70, medium effect size, p = <0.001), greater force at the fourth metatarsophalangeal (MTP) joint (d=0.28, small effect size, p = 0.13), and fifth MTP joint (d=0.37, small effect size, p = 0.10) and greater pressure at the fifth MTP joint (d=0.34, small effect size, p = 0.13). They also displayed lower force (d=0.40, small effect size, p = 0.02) and pressure at the hallux (d=0.50, medium effect size, p = <0.001) and lower force (d=0.54, medium effect size, p = <0.001) and pressure at the lesser toes (d=0.48, small effect size, p = <0.001) compared with controls.
Midfoot OA appears to be associated with lowering of the medial longitudinal arch, greater lateral push off and less propulsion at toe off. Longitudinal studies are needed to establish causal relationships.

Distal tibialis anterior tendinopathy (DTAT) is a chronic condition that may lead to functional impairment and secondary forefoot deformities when left untreated. Current clinical practice is mainly guided by case reports and small retrospective case series; little consensus exists on which treatment protocol is most effective. This study aims to assess a conservative treatment for DTAT consisting of PRP infiltration and walking cast immobilization.
This prospective study included 18 feet in 18 patients, recruited between September 2020 and September 2022 at a single institution. Ultrasonography was performed; leukocyte-poor PRP was infiltrated around the tibialis anterior tendon insertion. Walking cast immobilization was used for 3 weeks after infiltration, followed by eccentric exercises of the DTAT, and gastrocnemius-soleus muscle complex stretching. Clinical findings, visual analog scale (VAS), Foot Function Index (FFI), and American Orthopaedic Foot & Ankle Society (AOFAS) midfoot scores were recorded at inclusion, and 6 and 12 weeks after PRP infiltration. Minimal clinically important difference (MCID) limits were researched to assess clinical relevance of statistical outcomes. Means were determined for age, sex, and body mass index (BMI). One-way repeated measures ANOVA was performed over time for FFI, AOFAS, and VAS scores.
Mean age was 65 years with a mean BMI of 25. Tendon thickening and hypoechogenicity were the most commonly reported ultrasonographic findings. Significant improvement from baseline VAS (VASrest: 4.71 ± 2.7, VASactivity: 5.66 ± 2.5) to 12 weeks follow-up (VASrest: 2.14 ± 2.7, VASactivity: 3.34 ± 2.5) was found. Both AOFAS and FFITotal improved significantly from baseline (AOFAS: 66.9 ± 3.3, FFITotal: 32.9 ± 3.3) to 6-week follow-up (AOFAS6w: 79.4 ± 3.3, P = .019; FFITotal: 19.4 ± 3.3, P = .011). No statistically significant further improvement was found at 12 weeks compared to 6 weeks\' follow-up. Two (11%) patients chose operative treatment because of persisting symptoms.
We found that PRP infiltration with walking cast immobilization as a first-line treatment was associated with general early symptom improvement.
Level IV, case series.

BACKGROUND: Midfoot arthrodesis is a common procedure performed both for arthritis and correction of deformity. The optimal fixation for midfoot arthrodesis has not been established, though numerous studies have been investigating the fixation techniques of midfoot arthrodesis. The purpose of this study was to compare the union rate of midfoot arthrodesis using 4 different fixation strategies and investigate risk factors of nonunion following midfoot arthrodesis.
METHODS: A retrospective chart review was performed for patients who underwent midfoot joint arthrodesis between January 2014 and May 2019. The rates of nonunion and postoperative complication were compared among 4 different fixation constructs: staple fixation, compression plate fixation, compression plate with lag screw fixation, and compression screw fixation. Predictors of nonunion following midfoot arthrodesis were investigated through a multivariable logistic regression analysis. A total of 95 patients (99 feet), including 240 midfoot joints were included in this study. The mean follow-up period was 78.4 weeks.
RESULTS: Overall, bony union was achieved in 86 out of 99 (86.9%) patients, which included 218 out of 240 (90.8%) midfoot joints. A significant difference in the nonunion rate according to the type of fixation construct was found (P = .011); the compression screw alone fixation construct was noted to have a significantly higher nonunion rate than other fixation constructs. Diabetes mellitus (odds ratio [OR] = 0.179 [95% CI: 0.059, 0.542]), the type of fixation construct (compression screw alone; OR =1.789 [95% CI: 1.071, 2.978]), lack of adjuvant bone graft (OR = 2.803 [95% CI: 1.081, 7.268], and postoperative nonanatomical alignment (OR = 3.937 [95% CI: 1.278, 12.126]) were identified as independent predictors of nonunion following midfoot arthrodesis.
CONCLUSIONS: The rate of nonunion following midfoot arthrodesis among 4 different commonly used fixation constructs was compared in this study. Risk factors of nonunion were investigated revealing that diabetes mellitus, compression screw fixation alone, lack of adjuvant bone graft, and postoperative nonanatomical alignment are independent predictors of nonunion following midfoot arthrodesis.
UNASSIGNED: Level III: Comparative cohort study.

The medial, intermediate, and lateral cuneiforms play a pivotal role in foot biomechanics. When correcting deformities of this joint complex understanding the clinical anatomy remains imperative to provide both anatomic reduction and appropriately sized fixation. This study qualitatively and quantitatively describes the distal and intercuneiform articulations and their clinical implications. The cuneiform complex of 10 fresh-frozen cadavers was dissected, and the width of the complex was measured with digital calipers. Following further dissection, the distal articular surface shapes of each cuneiform were described, and the individual heights and widths were measured. The intercuneiform articular facets were described and the protrusion distances, between the medial and lateral cuneiforms with the intermediate cuneiform, were measured. The width of the joint complex was 44.74 ± 3.40 mm. The medial cuneiform height, width, dorsal anterior, and plantar protrusion distances were 32.58 ± 2.77 mm, 14.08 ± 2.26 mm, 8.51 ± 2.17 mm, and 6.66 ± 1.21 mm, respectively. The intermediate cuneiform height and width was 23.05 ± 1.92 mm and 9.59 ± 1.85 mm, respectively. The lateral cuneiform height, width, dorsal, and plantar anterior protrusion distances were 23.38 ± 2.67 mm, 10.98 ± 3.01 mm, and 6.76 ± 1.43 mm, and 4.19 ± 1.10 mm respectively. The anterior surface of the medial, intermediate, and lateral cuneiforms was described as reniform, triangular, and triangular, respectively. The majority of intermediate cuneiforms shared an inverted L-shaped articulation with the medial cuneiform, and a B-shaped articulation with the lateral cuneiform. The shapes and sizes of distal and intercuneiform articulations were described with shared anatomical features across cadavers. Understanding the dimensions of the respective surfaces allows for anatomically appropriate fixation size.

The fourth and fifth tarsometatarsal joint, consisting of the fourth and fifth metatarsal and the cuboid, imparts a significant amount of motion to the foot during ambulation. Injury to this joint complex, through chronic deformation or acute trauma, often necessitates arthroplasty, arthrodesis, or fusion. Currently, there exists no studies that investigate the anatomy of this articulation. The purpose of this study is to describe the medial and lateral anterior cuboid articulations which allows for surgical planning and the advancement of hardware design. Twenty fresh-frozen below-the-knee cadaver legs were thawed and the cuboids were excised. The width and height of the entire joint complex were measured as the longest span across the total articular surface of the anterior cuboid. The width and height of each articular facet were recorded as the span across the geometric bisection of each individual surface. The mean anterior cuboid articulation width and height was 25.62 mm and 16.74 mm, respectively. The mean medial cuboid articulation width and height was 11.7mm and 13.65 mm, respectively. The mean lateral cuboid width and height was 16.74 mm and 12.78 mm, respectively. The medial articulation maintained a larger mean height and narrower mean width than the lateral facet (p < .05). The unique anatomy of the lateral tarsometatarsal joint complex plays an important functional role and requires attention when deciding between arthrodesis or arthroplasty. Increasing the understanding of the clinical anatomy of this joint will better prepare surgeons and product designers to anticipate hardware needs.

In the modern treatment of Charcot neuroarthropathy, beam screw fixation is an alternative to plate and screw fixation. Exposure is minimized for implantation, and this technique supports the longitudinal columns of the foot as a rigid load-sharing construct. A published data review identified a paucity of data regarding metatarsal intramedullary canal morphology relevant to beam screw fixation. The purpose of the present study was to describe metatarsal diaphyseal morphology qualitatively and quantitatively in an effort to provide data that can be used by surgeons when selecting axially based intramedullary fixation. Twenty fresh-frozen cadaveric below-the-knee specimens were obtained. The metatarsals were exposed, cleaned of soft tissue, and axially transected at the point of the narrowest external diameter. Next, a digital caliper was used to measure the size and shape of the diaphysis of the first through fourth metatarsals. The diaphyseal canal shape was categorized as round, oval, triangular, or pear. The widest distance between the endosteal cortical surfaces was measured. Triangular endosteal canals were only found in the first metatarsal, and the remainder of the metatarsal canals were largely round or oval. These data help to approximate the size of fixation needed to achieve maximal screw-endosteal purchase.

OBJECTIVE: To derive a multivariable diagnostic model for symptomatic midfoot osteoarthritis (OA).
METHODS: Information on potential risk factors and clinical manifestations of symptomatic midfoot OA was collected using a health survey and standardised clinical examination of a population-based sample of 274 adults aged ≥50 years with midfoot pain. Following univariable analysis, random intercept multi-level logistic regression modelling that accounted for clustered data was used to identify the presence of midfoot OA independently scored on plain radiographs (dorso-plantar and lateral views), and defined as a score of ≥2 for osteophytes or joint space narrowing in at least one of four joints (first and second cuneometatarsal, navicular-first cuneiform and talonavicular joints). Model performance was summarised using the calibration slope and area under the curve (AUC). Internal validation and sensitivity analyses explored model over-fitting and certain assumptions.
RESULTS: Compared to persons with midfoot pain only, symptomatic midfoot OA was associated with measures of static foot posture and range-of-motion at subtalar and ankle joints. Arch Index was the only retained clinical variable in a model containing age, gender and body mass index. The final model was poorly calibrated (calibration slope, 0.64, 95% CI: 0.39, 0.89) and discrimination was fair-to-poor (AUC, 0.64, 95% CI: 0.58, 0.70). Final model sensitivity and specificity were 29.9% (95% CI: 22.7, 38.0) and 87.5% (95% CI: 82.9, 91.3), respectively. Bootstrapping revealed the model to be over-optimistic and performance was not improved using continuous predictors.
CONCLUSIONS: Brief clinical assessments provided only marginal information for identifying the presence of radiographic midfoot OA among community-dwelling persons with midfoot pain.