Hallux rigidus

Hallux rigidus (osteoarthrosis with restricted motion) is the second most common disabling deformity of the first metatarsophalangeal (MTP) joint after hallux valgus.

Terminology

Hallux limitus is distinct from hallux rigidus, the former referring to the functional pain secondary to lack of flexibility of the soft tissue structures, e.g. spasm of the gastrocnemius. Nevertheless, hallux limitus is thought to be a risk factor for hallux rigidus, therefore features of both conditions may co-occur ⁶.

Epidemiology

It is most commonly seen in middle-aged patients but can develop during adolescence. Unlike a hallux valgus, males appear to be slightly more affected than females. 

Diagnosis

The diagnosis of hallux rigidus is based on ¹:

• first MTP joint pain

• clinical findings of decreased dorsiflexion (<30°) and palpable osteophytes

Clinical presentation

Patients present with foot pain. The disability resulting from hallux rigidus is actually greater than that seen in hallux valgus because dorsiflexion at the metatarsophalangeal joint is severely restricted and painful. Removal of shoes does not relieve the pain ¹.

Radiographic features

The hallmark is osteoarthritis of the first MTP joint, which can be seen on many modalities ^1,8. Widening of the first metatarsal head is an additional finding whereas associated hallux valgus and the significance of the first metatarsal length are debated ².

Relative dorsal elevation of the first metatarsal to the lesser metatarsals (metatarsus primus elevatus) may be present but is debated whether it is causative or secondary ^2,9.

Classification

The grading system by Hattrup and Johnson is a radiographic classification that is commonly used ⁵:

• grade 1: mild to moderate osteophyte formation but with good joint space preservation 

• grade 2: moderate osteophyte formation with joint space narrowing and subchondral sclerosis 

• grade 3: marked osteophyte formation and loss of the visible joint space, +/- subchondral cyst formation

An alternative is the grading system by Coughlin and Shurnass ³:

• grade 0

  • dorsiflexion 40-60°

  • normal plain radiograph

  • no pain

• grade 1

  • dorsiflexion 30-40°

  • dorsal osteophytes

  • minimal or no other joint changes

• grade 2

  • dorsiflexion 10-30°

  • mild to moderate joint narrowing or sclerosis

  • presence of osteophytes

• grade 3

  • dorsiflexion less than 10°

  • severe radiographic changes

  • constant moderate to severe pain at extremities

• grade 4

  • stiff joint

  • severe changes with loose bodies and osteochondritis dissecans

Treatment and prognosis

Surgical treatments include osteophyte resection (cheilectomy) and capsular release, arthrodesis or arthroplasty ⁷.