Midfoot arthritis is a condition where the joints in the middle part of the foot develop inflammation and suffer cartilage degradation. This area, known as the midfoot or Lisfranc joint complex, is composed of small bones—the cuboids, cuneiforms, and the bases of the metatarsals—that form the foot’s arch. The Lisfranc joints are designed for stability, supporting the body’s weight and converting the foot into a rigid lever for walking and running. When the articular cartilage covering the ends of these bones breaks down, the bones begin to rub together, leading to pain, stiffness, and swelling. Multiple factors can contribute to this breakdown.
Post-Traumatic Origins
The most common cause of midfoot arthritis is a prior injury to the area, known as post-traumatic arthritis. This often follows significant trauma, such as a Lisfranc fracture-dislocation, which involves breaking bones or tearing the ligaments that stabilize the midfoot arch. The initial injury directly damages the cartilage surface.
Even if the bones are surgically repaired, the joint may not heal in perfect alignment, leading to a permanent shift in the foot’s biomechanics. This slight misalignment, or incongruity, causes weight and forces to be unevenly distributed across the joint surfaces. This repetitive, abnormal mechanical strain accelerates the deterioration of the compromised cartilage, resulting in arthritis years after the initial trauma.
Degenerative Wear and Tear
Midfoot arthritis can also develop without a clear history of injury, referred to as primary osteoarthritis. This form is attributed to cumulative stress and the natural aging process. Over decades, normal daily activities place repetitive mechanical stress on the joints, slowly eroding the cartilage.
The second and third tarsometatarsal joints are frequently affected because they have the least natural motion and bear the majority of the force during weight-bearing. This stress shifts the balance within the cartilage toward degradation, weakening the tissue structure. This process eventually progresses to visible loss of cartilage and joint function.
Structural and Biomechanical Contributors
The structure of the foot plays a significant role in determining how mechanical stress is distributed and can accelerate midfoot arthritis. Individuals with abnormal foot mechanics, such as high arches (pes cavus) or flat feet (pes planus), place uneven pressure on their midfoot joints. High arches concentrate weight on the outer edge, leading to instability, while flat feet cause the arch to collapse, straining inner midfoot structures.
Increased body weight is a major contributor to mechanical load, as the midfoot must support the entire body with every step. An increase in body mass is directly associated with elevated peak plantar pressures, overloading the joint tissues. This increased loading is a primary link between obesity and the development of midfoot osteoarthritis. Repetitive high-impact activities, such as certain sports or occupations requiring prolonged standing, compound this effect by transmitting large ground reaction forces through the midfoot complex.
Systemic Disease Links
Midfoot arthritis can also arise as a manifestation of a systemic inflammatory or metabolic disease, distinctly different from mechanical wear and tear. Conditions like Rheumatoid Arthritis (RA) and Psoriatic Arthritis involve the body’s immune system mistakenly attacking the healthy joint tissues. This autoimmune response causes chronic, widespread inflammation within the joint’s lining, leading to cartilage destruction across multiple joints.
Another systemic cause is gout, a metabolic disorder resulting from persistently high levels of uric acid in the blood. When the body produces too much uric acid or the kidneys cannot excrete enough of it, the acid crystallizes into sharp, needle-like urate crystals. These crystals deposit within the joint fluid of the midfoot, triggering an intense inflammatory reaction, which quickly damages the cartilage and joint lining.