What types of injuries or conditions are cam (controlled ankle movement) boots suitable for?

CAM Boot Indications for Foot and Ankle Injuries

CAM (Controlled Ankle Movement) boots are appropriate for stable foot and ankle injuries requiring immobilization and offloading, including avulsion fractures, zone 1 fifth metatarsal fractures, mild ankle sprains, and post-operative foot conditions, but should not be used as primary treatment for unstable injuries requiring rigid immobilization or active Charcot neuro-osteoarthropathy. 1, 2

Primary Indications

Fracture Management

• Avulsion fractures of the foot are effectively managed with walking boots as first-line treatment when fracture fragments are small, non-articular, or minimally displaced 1
• Zone 1 proximal fifth metatarsal fractures can be treated with CAM boots, achieving bone healing in an average of 7.2 weeks with similar functional outcomes to hard-soled shoes 2
• CAM boots provide adequate immobilization while allowing continued ambulation during recovery 3

Ankle Injuries

• Mild ankle sprains (grade I-II lateral ankle sprains) can be managed with CAM boots during the initial immobilization phase, though early mobilization and physical therapy referral are preferred over prolonged immobilization 4, 5
• High fracture boots demonstrate significantly less ankle motion during weightbearing (4.8 ± 2.0 degrees) compared to low fracture boots (7.8 ± 3.4 degrees), approaching the immobilization achieved by short leg casts (3.4 ± 1.4 degrees) 6

Diabetic Foot Conditions

• Diabetic foot ulcers can be managed with removable cast boots/walkers as part of offloading interventions, though non-removable devices are strongly preferred for better adherence and outcomes 7
• CAM boots are described as prefabricated removable knee-high boots with rocker or roller outsole configuration, padded interior, and adjustable insoles 7

Biomechanical Effects

Ankle Immobilization

• CAM boots effectively restrict ankle range of motion in non-weightbearing conditions (2.2-2.3 degrees vs 3.6 degrees in shoes) 6
• High fracture boots provide better weightbearing immobilization than low fracture boots, though neither matches the restriction of short leg casts 6

Pressure Redistribution

• CAM boots effectively redistribute plantar pressure from the forefoot to the hindfoot 3
• All CAM boot types (low and high) significantly reduce peak plantar surface forces (154.5-172.6% body weight) compared to normal shoes (195.0% body weight) 6

Critical Contraindications and Limitations

When NOT to Use CAM Boots

• Active Charcot neuro-osteoarthropathy requires non-removable knee-high devices (total contact cast or walker made non-removable) as the strong recommendation, not standard removable CAM boots 7
• Below-ankle offloading devices should not be used as primary treatment for avulsion fractures as they provide inadequate immobilization 1
• Unstable fractures requiring rigid immobilization may be better served by short leg casts rather than CAM boots 6

Important Caveats

• Compensatory mechanisms occur at neighboring joints: CAM boot wear causes kinetic and kinematic alterations at the knee and hip, potentially explaining secondary site pain commonly reported by patients 3
• Leg length discrepancy created by CAM boots can cause balance problems and joint strain; adding a leg length-evening orthotic to the contralateral shoe improves patient-reported balance (2.0±1.5 vs 3.2±1.8 without orthotic) 8
• Prolonged immobilization is detrimental: For ankle sprains, delayed referral to physical therapy and extended immobilization (such as 6 weeks in a CAM boot) are associated with poorer outcomes compared to early mobilization 4

Post-Operative Applications

• Post-operative foot conditions can be managed with post-operative shoes (prefabricated shoes with roomy and soft upper) or CAM boots depending on the required level of immobilization 7
• Temporary shoes or CAM boots may be used temporarily to treat foot ulcers in diabetic patients 7

Practical Considerations

• Low fracture boots may be more suited for non-weightbearing or immobilizing the foot rather than the ankle during weightbearing 6
• High fracture boots provide superior ankle immobilization during weightbearing activities 6
• Functional rehabilitation should begin after the appropriate immobilization period, including NSAIDs for pain control, graded exercise, and proprioceptive training 9, 5