Hallux Valgus Flashcards
What’s a normal metatarsus adductus angle?
Normal - 0 to 15º
Mild - 16 to 19º
Moderate - 20 to 25º
Severe - > 25º
What’s a normal 1-2 intermetatarsal angle?
Normal - < 9º
Mild - ≤ 11 º
Moderate - 12 to 16º
Severe - > 16 º
What’s a normal hallux valgus angle?
Normal - < 15º
Mild - < 20 º
Moderate - 20 to 40º
Severe - > 40 º
What’s a normal hallux interphalangeal angle?
Normal - 0 to 10º
What’s a normal PASA angle?
Normal - ≤ 6 º
What’s a normal DASA angle?
Normal - 5 º
What’s the normal metatarsal protrusion distance?
Normal is 2 mm
What’s a normal tibial sesamoid position?
Normal is position 1 to 3
What’s the normal metatarsal break angle?
Normal is 142 º
What’s the normal kite (talocalcaneal) angle?
Normal is 15 to 30 º
What’s the normal first metatarsal declination angle?
Normal is 20 to 30º
What’s the normal calcaneal pitch (inclination) angle?
Low: 10 to 20 º - indicative of pes planus
Medium: 20 to 30 º
High: ≥ 30 º - indicative of pes cavus
What’s the normal Meary’s (talar-first metatarsal) angle?
Angle > 4 º (convex upward): pes cavus
Angle > 4 º (convex downward): pes planus
Explain the pathophysiology of osteoarthritis
Once the cascade begins, water content in the cartilage layer increases and the concentration of proteoglycans decreases. Grossly, the cartilage surface becomes soft and friable, and disruption of the smooth cartilage surface occurs, causing it to fissure initially at the surface (flaking) and then extend vertically into the deeper zones (fibrillation). The normally smooth cartilage surface shows cracks and thinning. The synovium becomes fibrotic and hyperaemic, with chronic inflammatory cell infiltration. With repeated mechanical trauma, fragments of articular cartilage may break off into the joint, forming loose bodies. Eventually, the exposed (subchondral) bone becomes hard/thickened and highly polished, creating an ivory-like, eburnated bone surface. Crevices/fissures in the bone eventually enlarge and, due to the pressure within the joint (usually on the weight-bearing surface), synovial fluid is pressed into the deeper zones, forming subchondral bone cysts. Marginal outgrowths of ossified cartilage (osteophytes) form on the periphery of the joint, extending from the free articular space along the path of least resistance; because of the vascularisation in the subchondral bone, proliferation of adjacent cartilage and enchondral ossification occur.
What’s the current opinion on the aetiology of hallux valgus?
- Hypermobility of the medial column –> excessive pronation –> imbalance of intrinsic musculature about the first ray –> development of HAV.
- Inflammatory arthritides can produce secondary structural changes in the foot.
- Neuromuscular diseases (e.g. cerebral palsy, Ehler Danlos Syndrome, Marfan syndrome) –> muscle imbalance with possible structural changes
- Traumatic conditions around the MTPJ-1
