Foot and ankle
Anatomy
Muscles, nerves, arteries: Figures 8-3, 8-4AB, and 8-5A-C
Figure 8-3. Dorsal view of the foot sole. (From Netter illustration from www.netterimages.com. Copyright Elsevier Inc. All rights reserved.)
Physical examination
Inspect for edema, erythema, ecchymosis, deformity, callus formation, ulceration, and hairlessness. On standing examination, note hindfoot alignment. Assess gait pattern.
Normal range of motion: Table 8-2
Table 8-2.
Normal Ankle/Foot Range of Motion
| Ankle dorsiflexion | 10-23 degrees |
| Ankle plantarflexion | 23-48 degrees |
| Inversion | 5-35 degrees |
| Eversion | 5-25 degrees |
| First metatarsophalangeal dorsiflexion | 45-90 degrees |
| First metatarsophalangeal plantarflexion | 10-40 degrees |
Differential diagnosis: Table 8-4
Table 8-4.
| Anterior ankle pain | Ankle arthritis, osteochondral dessicans talus |
| Medial ankle pain | Posterior tibial tendinopathy, medial malleolar injury |
| Lateral ankle pain | Peroneal tendinopathy, ankle sprain |
| Posterior ankle pain | Achilles tendinopathy or rupture, os trigonum, posterior impingement |
| Midfoot | Lisfranc injury, midfoot arthritis |
| Forefoot | Metatarsal fracture, stress fracture, metatarsalgia |
| Heel pain | Plantar fasciitis, calcaneal stress fracture, insertional Achilles tendinopathy |
| Great toe | Hallux rigidus, hallux valgus |
| Lesser toes | Toe fracture, hammertoe deformity, Morton neuroma |
Ankle arthritis
Imaging
Radiographs: Weight-bearing anteroposterior (AP), mortise, lateral
Treatment options
Operative management
Operative indications
Ankle arthrotomy with debridement/loose body removal
• Generally has limited value and indicated only in mild arthritis without significant joint space narrowing
• Indications: painful tibiotalar arthritis not responsive to nonoperative treatment, failed arthroplasty
• Contraindications: acute infection, acute neuropathic arthropathy, severe vascular disease
• Indications: tibiotalar arthritis not responsive to nonoperative management, low demand patients older than age 50-55 years, weight < 200 lb, maintained range of motion, normal/near normal alignment, no preexisting subtalar arthritis.
• Contraindications: acute infection, significantly diminished bone stock, neuropathy, severe vascular disease. Relative contraindications include deformity greater than 5 degrees and talar avascular necrosis.
Informed consent and counseling
• Major risks include nonunion (<10%), wound complications, nerve injury, infection, deep vein thrombosis (DVT), hardware loosening/failure, and development of arthritis in hindfoot/subtalar joint. A risk of amputation exists in cases of severe complication (≤5%).
• The complication rate increases with nicotine use, neuropathy, and vascular disease.
• Informed consent and counseling: Risks are similar to arthrodesis (infection, wound complications, DVT, hardware loosening). Recent studies report 10% to 30% reoperation rate and survival rates of 77% to 90% at 5- and 10-year follow-up. If surgery fails, consider conversion to arthrodesis (contraindicated in infection). Limited revision options are available.
Surgical procedures
Ankle arthrodesis (Fig. 8-8AB)
Figure 8-8. Postoperative anteroposterior (A) and lateral (B) views following ankle arthrodesis using anterior plate.
• Many implants for fixation are available, the most common being an anterior plate with cross-screws. An intraoperative radiograph is used to confirm appropriate placement.
• Open anterior approach is most common. An incision is made over the ankle between anterior tibial tendon and extensor hallucis longus (EHL).
• Structures at risk include superficial peroneal nerve and neurovascular bundle (posterior to EHL).
• The neurovascular bundle is mobilized, and the tibial osteophytes are removed to visualize joint. The joint is prepared by removing any remaining articular cartilage, and microfracturing and/or drilling the subchondral bone. A lamina spreader can be helpful for visualization.
• Align neutral dorsiflexion/plantarflexion, 0 to 5 degrees hindfoot valgus, 5 degrees external rotation. An intraoperative radiograph is used to determine correct alignment for fixation.
• A sugar tong splint is applied in the operating room after closure. The patient remains non–weight bearing.
Estimated postoperative course
• Sutures are removed and radiographs are obtained. A non–weight-bearing cast is applied for 4 weeks.
• Radiographs reviewed. The patient is transitioned to a weight-bearing cast for an additional 6 weeks.
• Remove cast. Obtain radiographs to evaluate for healing.
• Physical therapy is generally not indicated, but some patients may need some therapy for gait training.
Total ankle arthroplasty (Fig. 8-9AB)
• Second- and third-generation implants are now available, but there are still limited data on longevity. First-generation implants have a high failure rate.
• Both 2 and 3 component implants are available, primarily depending on surgeon preference.
• An open anterior approach is used as described in ankle arthrodesis. Major structures at risk include the superficial peroneal nerve and neurovascular bundle.
Subtalar arthritis
Imaging
Treatment options
Initial treatment should be nonoperative. NSAIDs, lace-up ankle brace, weight loss if indicated, activity modification (limit uneven surfaces), and corticosteroid injections
Operative management
Operative indications
Informed consent and counseling
Risks include infection, wound complications, arthritis in surrounding joints, nonunion (reported rates 0.5%), DVT, symptomatic hardware (especially if screw heads are prominent posteriorly). Some patients feel instability on uneven ground. At-risk structures: superficial peroneal and sural nerves, peroneal tendons
Surgical procedure
• Lateral incision is made about 2 cm distal to lateral malleolus, extending to the base fourth metatarsal. Extensor digitorum brevis is reflected to expose subtalar joint. Peroneal tendons are elevated from lateral calcaneous and retracted.
• Any remaining cartilage is removed, and the joint is debrided to cancellous bone.
• Fusion is performed at 5 degrees valgus. Two cannulated screws are placed from the non–weight-bearing portion of calcaneus toward the anterior margin posterior facet into the talus. Divergent screws have improved compression forces compared with parallel screws or a single screw. Intraoperative radiographs and guidewires are used to ensure appropriate placement of screws (Fig. 8-11).
Figure 8-11. Lateral radiograph status post subtalar arthrodesis using two divergent cannulated screws.
• The patient may require bone grafting or bone block if bone loss is present from previous trauma/calcaneal fracture.
• A posterior splint is applied in the operating room after closure. The patient remains non–weight bearing for 2 weeks.
Estimated postoperative course
Postoperative 2 weeks: sutures removed. Non–weight bearing in a boot. Remove boot multiple times daily for ankle motion to prevent stiffness.
Postoperative 6 weeks: radiograph reviewed. Start weight bearing in boot from weeks 6 to 12.
Ankle fractures
Physical examination
Edema, ecchymosis, tenderness over fracture site. Medial tenderness without medial malleolus fracture suggests deltoid ligament injury; does not necessarily signify unstable ankle joint
Fracture blisters with severe edema and soft tissue trauma
Visual deformity present if ankle dislocated or severe displacement of fracture
Imaging
• Weight-bearing ankle AP, mortise, lateral. Assess fracture, alignment, displacement.
• Weight bearing foot AP, oblique, lateral. Assess for fracture or malalignment.
• Stress radiographs of the ankle should be performed for isolated fibular fractures at the level of the ankle joint. To perform, gravity stress or external rotation and/or abduction stress is applied in a non–weight-bearing mortise view. Medial clear space greater than 4 to 5 mm indicates deltoid ligament injury and ankle instability (Fig. 8-12).
• Compare with contralateral ankle (mortise view is best). A 2-mm side-to-side difference in medial clear space indicates instability.
• CT scans are helpful to evaluate comminution and subtle displacement. Scan should be performed of bilateral ankles to compare syndesmosis and medial clear space.
• MRIs are usually not necessary but can be useful to evaluate the deltoid ligament and help determine ankle stability.
Classification systems
Danis-Weber classification is based on the location of the fibular fracture and does not address the medial structures.
• Type A: Transverse fracture at the level of or distal to the tibial plafond
• Type B: Spiral, oblique fracture at the level of distal tibiofibular joint and extends proximally. Associated with possible disruption of syndesmosis (Fig. 8-13).
• Type C: Fracture proximal to distal tibiofibular joint. Syndesmosis completely disrupted; anterior and posterior tibiofibular ligaments and interosseous membrane ruptured (Fig. 8-14)
Initial treatment
Treatment options
Weber A fractures: Nearly all can be treated nonoperatively, even with mild displacement.
• Immobilization in cast or walking boot, weight bearing as tolerated. Most fractures heal in 6 weeks.
• Consider nonoperative management when medial clear space is less than 4 to 5 mm and less than 2 mm greater than contralateral side on stress and static radiographs.
• Immobilization in cast or walking boot for 6 weeks. Weight bearing is progressed as tolerated.
• Frequent follow-up with radiographs (weekly for first 2 to 3 weeks). Surgical fixation is recommended if there is a change in stability or alignment.
• After 6 weeks of immobilization, transition to brace. Physical therapy may be helpful to regain motion and strength.
Operative management
Codes
Informed consent and counseling
Risks include wound complications, infection, nonunion, and DVT. The rate of complication is significantly higher in diabetics, nicotine users, and patients with peripheral vascular disease. Post-traumatic arthritis may still occur despite proper stabilization. Major structures at risk are the superficial peroneal nerve (crosses fibula approximately 4 to 5 cm proximal to joint) and saphenous vein (for medial incisions).
Surgical procedure
Open Reduction, Internal Fixation
• Distal fibular fractures—Multiple hardware options are available including locking and nonlocking plates and screws. Locking plates should be used when bone quality is poor or a patient is at high risk for nonunion (diabetes, osteoporosis).
• Medial malleolus fractures—Fixation devices include lag, partially threaded, or cannulated screws; Kirshner wires; tension bands; and buttress plate (used only for vertical sheer fractures to prevent proximal migration of fracture fragment).
Use a lateral approach for fixation of distal fibula, syndesmosis, and possibly posterior malleolus. Longitudinal incision is made directly over the distal fibula. Fibular fracture is reduced and stabilized, restoring proper length and rotation. Intraoperative radiograph is used for reduction, to confirm proper screw length, and to determine stability. After ORIF fibula, a radiograph is taken to evaluate medial clear space. If widening is present after ORIF fibula, a syndesmotic screw is placed (Fig. 8-15).
Estimated postoperative course
Postoperative 2 to 3 weeks: Sutures removed. Radiographs are obtained at each postoperative visit until complete healing is noted.
Postoperative 8 to 10 weeks: Discontinue boot and progress to shoe with ankle brace.
Plantar fasciitis (PF)
Morton’s (intermetatarsal) neuroma
Physical examination
Tenderness to palpation of intermetatarsal space. Pain is not reproduced with palpation of metatarsal heads or metatarsal-phalangeal (MTP) joints.
Mulder’s sign: Squeeze forefoot medial to lateral and apply dorsal pressure over affected web space. Positive test is audible or palpable click that causes pain.
Imaging
Treatment options
Surgical procedure
• Dorsal approach: A longitudinal incision is made over the involved web space. The dorsal interosseous fascia is split and retracted. Interosseous muscle is partially detached, metatarsal heads are retracted, and the intermetatarsal ligament is cut. The neuroma is exposed by retracting the digital artery and lumbrical muscle.
• Plantar approach: This is generally reserved for revision procedures. A longitudinal incision is made between the metatarsal heads. The plantar fascia is split and retracted to expose the neuroma.
• Once neuroma is exposed, it is dissected proximally and cut. The proximal stump retracts into the intrinsic muscles.
• Evaluate vascular status after excision to ensure digital artery intact and functioning.
Estimated postoperative course
Dorsal approach: weight bearing as tolerated in hard-soled post-operative shoe. Progress to normal shoe wear and activities as tolerated once incision healed, usually between 2 and 3 weeks postoperative.
The plantar approach requires greater protection with a splint or cast boot and more limited weight bearing to prevent wound complications. Sutures are removed 2 to 3 weeks postoperative. Progress to normal shoe wear and activities as tolerated once the wound has completely healed. This may be 3 to 4 weeks postoperative.
Diabetic foot and charcot arthropathy
Physical examination
Visual deformities: Claw-toe deformities are common from loss of intrinsic muscle tone. Rocker-bottom midfoot deformity is often present in Charcot arthropathy of midfoot.
• Inspect for presence of corns or calluses, open wounds, swelling, trophic changes, dependent rubor (arterial insufficiency), and bony prominences.
• Ulcers often develop at sites of callus formation or as a result of microtrauma.
• Increased warmth compared with the contralateral side can indicate Charcot arthropathy, venous insufficiency, or infection.
Imaging
Radiograph: weight-bearing AP, lateral, oblique of foot and AP, lateral, mortise of ankle
Classification systems
Multiple classification systems for diabetic foot ulcers, and Charcot arthropathy
Pinzer “risk factor” system to guide treatment of diabetic patients
• Risk Category 0: Normal appearance and sensation, mild to no deformity
• Risk Category 1: Normal appearance, insensate, no deformity
• Risk Category 2: Insensate foot with deformity, no history of prior ulcer
• Risk Category 3: Insensate foot with deformity and history of prior ulcer
Classification system of Charcot arthropathy:
• Stage 0: Clinical examination findings of erythema and edema. Radiographs are normal.
• Stage I: Fragmentation or dissolution phase. Radiographs demonstrate periarticular fragmentation, subluxation, or dislocation of joint. On examination, foot is warm, edematous, and erythematous.
• Stage II: Coalescence period, early healing phase. Radiographs show early sclerosis, fusion of bony fragments, and absorption of debris. On examination, there is less erythema and warmth than stage I.
• Stage III: Reconstruction phase. Radiographs reveal subchondral sclerosis, osteophytes, and narrow or absent joint spaces. On examination, visual deformity is present and there is no acute inflammation.
Treatment options
At-risk patients without Charcot arthropathy: based on Pinzur classification
• Risk Category 0: education, normal footwear, yearly clinical examination
• Risk Category 1: education, daily foot self-examination, protective over-the-counter insoles, appropriate footwear, biannual clinical examination
• Risk Category 2: education, daily foot self-examination, custom pressure-dissipating accommodative orthoses, inlay depth soft-leather shoes, clinical examination every 4 months
• Risk Category 3: education, daily foot self-examination, custom pressure-dissipating orthoses, inlay depth soft-leather shoes, clinical examination every 2 months
Charcot arthropathy: based on stage
• Stage I: immobilization using total contact casting, which reduces total load on the foot by one third. Length of immobilization depends on progression of disease/collapse, often 2 to 4 months.
• Stage II: ankle-foot orthosis or Charcot restraint orthotic walker (CROW) boot.
• Stage III: accommodative shoe and custom insole to decrease pressure on bony prominences
Surgical procedures
Amputation: Level of amputation and surgical techniques vary, depending on disease involvement.
Arthrodesis: As described in earlier sections of the chapter
Metatarsal fractures (including jones fracture)
Imaging
Classification system
Fifth metatarsal fractures are classified on the basis of location. Treatment recommendations are based on this classification system.
• Zone 1 (avulsion): Fifth metatarsal tuberosity fracture. Most common type (>90%). Often extends from insertion of peroneal brevis to involve the tarsometarsal joint.
• Zone 2 (Jones fracture): Distal to the tuberosity at metaphyseal-diaphyseal junction. Fracture extends to fourth to fifth intermetatarsal joint. Mechanism is adduction or inversion of the forefoot (Fig. 8-18).
Figure 8-18. Jones fracture of the fifth metatarsal.
• Zone 3: Proximal diaphyseal shaft fracture. Rare, less than 3% of fifth MT fractures. Frequently a stress injury and patients may report prodromal pain.
