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8. Foot and Ankle MCQs

Practice Set 334 of 353

This practice set contains high-yield board review questions covering key concepts in 8. Foot and Ankle. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 6661

Topic: Forefoot

A 72-year-old woman presents with severe first metatarsophalangeal (MTP) joint pain and a recurrent, rigid hallux valgus deformity 15 years after previous bunion surgery. Radiographs demonstrate severe osteoarthritis of the first MTP joint with a prominent retained screw. The decision is made to perform hardware removal and a first MTP arthrodesis. What is the optimal position for fusion of the first MTP joint?

. 0-5 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotation
. 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotation
. 10-15 degrees of varus, 20-25 degrees of dorsiflexion relative to the floor, and neutral rotation
. 0-5 degrees of valgus, 0-5 degrees of plantarflexion relative to the floor, and neutral rotation
. 20-25 degrees of valgus, 30-40 degrees of dorsiflexion relative to the floor, and neutral rotation

Correct Answer & Explanation

. 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotation

Explanation

Correct Answer: 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotationFirst MTP joint arthrodesis is a reliable salvage procedure for failed bunion surgery with severe arthritis. The optimal position for fusion is critical for a good functional outcome and to prevent transfer metatarsalgia or interphalangeal joint arthritis. The recommended position is 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor (which equates to about 25-30 degrees of dorsiflexion relative to the first metatarsal shaft), and neutral rotation. This allows for normal toe-off during the gait cycle and accommodates most standard footwear.

Question 6662

Topic: 8. Foot and Ankle

A 60-year-old woman presents with medial ankle pain and swelling. She has pain along the posterior tibial tendon but can successfully perform a single-leg heel raise. Which of the following best describes the primary biomechanical function of the posterior tibial tendon during the normal gait cycle?

. Decelerates subtalar pronation during the contact phase
. Accelerates subtalar supination during the swing phase
. Acts as the primary dorsiflexor of the ankle during heel strike
. Everts the hindfoot during the midstance phase
. Plantarflexes the first ray during toe-off

Correct Answer & Explanation

. Decelerates subtalar pronation during the contact phase

Explanation

Correct Answer: AThe posterior tibial tendon (PTT) plays a crucial role in normal foot biomechanics during the stance phase of gait. During the initial contact phase, the PTT fires eccentrically to decelerate subtalar joint pronation and internal rotation of the tibia. During the midstance phase, it fires concentrically to supinate the subtalar joint, which locks the transverse tarsal joint (talonavicular and calcaneocuboid joints), creating a rigid lever arm for effective push-off. It does not evert the hindfoot (it inverts it) and is active during stance, not swing.

Question 6663

Topic: Midfoot & Hindfoot
A 55-year-old woman presents with a progressive flatfoot deformity. Examination reveals a flexible hindfoot valgus and forefoot abduction. She is unable to perform a single-leg heel raise on the affected side. She has failed 6 months of conservative management including a custom ankle-foot orthosis and physical therapy. Which of the following surgical interventions is most appropriate?
. Tenosynovectomy and debridement of the posterior tibial tendon
. Flexor digitorum longus (FDL) transfer and medial displacement calcaneal osteotomy
. Subtalar arthrodesis
. Triple arthrodesis
. Tibiotalocalcaneal arthrodesis

Correct Answer & Explanation

. Flexor digitorum longus (FDL) transfer and medial displacement calcaneal osteotomy

Explanation

This patient has Stage II posterior tibial tendon dysfunction (PTTD), characterized by a flexible flatfoot deformity and the inability to perform a single-leg heel raise. The standard of care for Stage II PTTD that has failed conservative management is a joint-sparing procedure, typically consisting of a flexor digitorum longus (FDL) tendon transfer to the navicular combined with a medial displacement calcaneal osteotomy (MDCO) to correct the mechanical axis of the hindfoot. Tenosynovectomy alone is reserved for Stage I (no deformity, able to heel raise). Triple arthrodesis is indicated for Stage III (rigid deformity).

Question 6664

Topic: 8. Foot and Ankle

A 70-year-old woman with severe hallux rigidus and a failed previous bunionectomy is undergoing a 1st metatarsophalangeal (MTP) joint arthrodesis. To optimize her postoperative gait and function, what is the ideal position for fusion of the 1st MTP joint?

. 0-5 degrees of valgus, 5-10 degrees of dorsiflexion relative to the floor
. 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor
. 10-15 degrees of valgus, 10-15 degrees of plantarflexion relative to the first metatarsal
. 20-25 degrees of valgus, neutral dorsiflexion relative to the floor
. Neutral valgus, 30 degrees of dorsiflexion relative to the floor

Correct Answer & Explanation

. 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor

Explanation

Correct Answer: BThe success of a 1st MTP arthrodesis relies heavily on the position of the fusion. The ideal position is approximately 10 to 15 degrees of valgus and 10 to 15 degrees of dorsiflexion relative to the floor (which corresponds to about 25 to 30 degrees of dorsiflexion relative to the longitudinal axis of the first metatarsal). This position allows for normal weight transfer during the toe-off phase of gait and accommodates most standard footwear. Excessive dorsiflexion causes shoe wear issues, while plantarflexion leads to excessive pressure on the interphalangeal joint.

Question 6665

Topic: Midfoot & Hindfoot
A 60-year-old woman presents with chronic pain along the medial aspect of her ankle. Examination reveals tenderness and swelling along the course of the posterior tibial tendon. She is able to perform a single-leg heel raise symmetrically, and there is no flexible or rigid flatfoot deformity present. She has undergone 8 weeks of cast immobilization, nonsteroidal anti-inflammatory drugs (NSAIDs), and physical therapy without significant relief. What is the most appropriate next step in management?
. Flexor digitorum longus transfer and medial displacement calcaneal osteotomy
. Subtalar arthrodesis
. Posterior tibial tendon tenosynovectomy
. Triple arthrodesis
. Spring ligament reconstruction

Correct Answer & Explanation

. Posterior tibial tendon tenosynovectomy

Explanation

This patient presents with Stage I posterior tibial tendon dysfunction (PTTD). Stage I is characterized by pain and swelling along the tendon, no clinical deformity, and the preserved ability to perform a single-leg heel raise. The initial treatment for Stage I PTTD is conservative, including immobilization (cast or boot), orthotics, NSAIDs, and physical therapy. When conservative management fails after an adequate trial (typically 3-6 months), surgical intervention is indicated. For isolated Stage I disease without deformity, a posterior tibial tendon tenosynovectomy is the treatment of choice. Flexor digitorum longus (FDL) transfer and medial displacement calcaneal osteotomy are indicated for Stage II PTTD (flexible flatfoot deformity, inability to perform a single heel raise). Triple arthrodesis is reserved for Stage III PTTD (rigid deformity with subtalar arthrosis).

Question 6666

Topic: Forefoot

A 70-year-old active woman presents with severe pain with weightbearing at the first metatarsophalangeal (MTP) joint. She underwent bunion surgery 25 years ago. Radiographs demonstrate severe first MTP joint arthrosis, a shortened first ray, and a prominent retained screw from a prior osteotomy. Conservative management has failed. What is the most reliable surgical option to provide long-term pain relief and restore function?

. First MTP joint arthrodesis
. Silicone implant arthroplasty
. Resection arthroplasty (Keller procedure)
. Revision first metatarsal osteotomy
. Cheilectomy

Correct Answer & Explanation

. First MTP joint arthrodesis

Explanation

Correct Answer: AThis patient presents with a failed prior bunion surgery resulting in severe first MTP joint arthrosis and a shortened first ray. The gold standard salvage procedure for a failed hallux valgus surgery with severe degenerative joint disease is a first MTP joint arthrodesis. Arthrodesis provides reliable, long-term pain relief, restores the weightbearing function of the first ray, and corrects any residual or recurrent deformity. Silicone implant arthroplasty has a high rate of failure, implant fracture, and reactive synovitis. A Keller resection arthroplasty can lead to further shortening of the first ray, transfer metatarsalgia, and a "cock-up" deformity. Cheilectomy is indicated for early-stage hallux rigidus without severe joint space narrowing, not for end-stage arthrosis following failed surgery.

Question 6667

Topic: 8. Foot and Ankle

A 60-year-old woman with chronic medial ankle pain is diagnosed with posterior tibial tendon dysfunction. As her condition progresses from Stage I to Stage II, she develops a flexible flatfoot deformity. Which of the following biomechanical changes occurs as a direct result of the hindfoot valgus deformity?

. The Achilles tendon line of pull shifts medial to the subtalar joint axis, acting as an invertor
. The Achilles tendon line of pull shifts lateral to the subtalar joint axis, acting as an evertor
. The transverse tarsal joints become locked during the stance phase of gait
. The peroneus brevis tendon becomes a primary invertor of the foot
. The spring ligament complex undergoes contracture and shortening

Correct Answer & Explanation

. The Achilles tendon line of pull shifts lateral to the subtalar joint axis, acting as an evertor

Explanation

Correct Answer: BIn posterior tibial tendon dysfunction, the loss of the primary dynamic stabilizer of the medial longitudinal arch leads to a progressive flatfoot deformity. As the hindfoot drifts into valgus, the calcaneus everts relative to the talus. This valgus shift moves the insertion of the Achilles tendon (on the posterior calcaneal tuberosity) lateral to the axis of the subtalar joint. Consequently, the Achilles tendon, which normally acts as a plantarflexor and mild invertor, becomes a deforming force that acts as an evertor of the hindfoot, further exacerbating the valgus deformity. The transverse tarsal joints become unlocked (parallel axes) in a flatfoot, leading to midfoot hypermobility. The spring ligament typically attenuates and lengthens, rather than contracting.

Question 6668

Topic: 8. Foot and Ankle

A 52-year-old diabetic man presents with a chronic, draining ulcer on the medial aspect of his right great toe. He was recently started on insulin. The development of this ulcer is primarily driven by diabetic neuropathy. Which of the following best describes the role of autonomic neuropathy in the pathogenesis of his foot ulcer?

. Loss of protective sensation leading to unrecognized repetitive microtrauma
. Atrophy of the intrinsic foot muscles resulting in claw toe deformities
. Decreased sweating leading to dry, cracked skin and arteriovenous shunting
. Demyelination of large motor fibers causing foot drop
. Hyperactivity of the sympathetic nervous system causing severe vasoconstriction

Correct Answer & Explanation

. Decreased sweating leading to dry, cracked skin and arteriovenous shunting

Explanation

Correct Answer: CDiabetic neuropathy affects sensory, motor, and autonomic nerves, all of which contribute to ulcer formation. Autonomic neuropathy leads to sudomotor dysfunction (decreased sweating), which causes the skin to become dry, brittle, and prone to cracking, creating portals of entry for infection. Additionally, loss of sympathetic tone leads to arteriovenous shunting, resulting in warm feet with bounding pulses but poor capillary nutrient flow to the skin. Sensory neuropathy causes the loss of protective sensation (unrecognized microtrauma). Motor neuropathy causes intrinsic muscle atrophy, leading to muscle imbalances and structural deformities like claw toes, which create abnormal pressure points.

Question 6669

Topic: Midfoot & Hindfoot
A 60-year-old woman presents with a 6-month history of medial ankle pain. Examination reveals tenderness along the course of the posterior tibial tendon, but she is able to perform a single-leg heel raise symmetrically without difficulty. MRI demonstrates tenosynovitis of the posterior tibial tendon without evidence of a tear. She has undergone 8 weeks of cast immobilization, nonsteroidal anti-inflammatory drugs (NSAIDs), and physical therapy, but continues to have debilitating pain. What is the most appropriate next step in management?
. Flexor digitorum longus (FDL) transfer to the navicular
. Medial displacement calcaneal osteotomy
. Tenosynovectomy of the posterior tibial tendon
. Subtalar arthrodesis
. Triple arthrodesis

Correct Answer & Explanation

. Tenosynovectomy of the posterior tibial tendon

Explanation

This patient presents with Stage I posterior tibial tendon dysfunction (PTTD), characterized by pain and swelling along the tendon, tenosynovitis on MRI, but no deformity and an intact ability to perform a single-leg heel raise. Conservative management includes immobilization, custom orthotics, NSAIDs, and physical therapy. When conservative treatment fails after a sufficient trial (typically 3-6 months), surgical intervention is indicated. For Stage I PTTD, a tenosynovectomy with or without tendon debridement is the procedure of choice. FDL transfer and medial displacement calcaneal osteotomy are indicated for Stage II PTTD, which involves a flexible flatfoot deformity and inability to perform a single heel raise. Arthrodesis procedures (subtalar or triple) are reserved for Stage III (rigid deformity) or Stage IV (ankle joint involvement) PTTD.

Question 6670

Topic: Forefoot

A 70-year-old woman presents with severe pain at the first metatarsophalangeal (MTP) joint. She underwent a bunion correction with screw fixation 25 years ago. Radiographs demonstrate severe degenerative joint disease of the first MTP joint with a prominent intra-articular screw. Conservative management, including stiff-soled shoes and intra-articular injections, has failed. What is the most reliable surgical option for long-term pain relief and functional improvement?

. Screw removal and Keller resection arthroplasty
. Screw removal and silicone implant arthroplasty
. Screw removal and first MTP joint arthrodesis
. Screw removal and cheilectomy
. Screw removal and synthetic hemiarthroplasty

Correct Answer & Explanation

. Screw removal and first MTP joint arthrodesis

Explanation

Correct Answer: CThis patient presents with end-stage arthritis of the first MTP joint (hallux rigidus) following a prior bunion surgery. First MTP joint arthrodesis is the gold standard and most reliable surgical option for severe first MTP arthritis, particularly in the setting of a failed prior surgery (salvage procedure). It provides excellent, durable pain relief and restores the weight-bearing function of the first ray. Keller resection arthroplasty can lead to transfer metatarsalgia, a "cock-up" deformity, and weakness of push-off. Silicone implant arthroplasty has historically high failure rates, risk of silicone synovitis, and bone loss. Cheilectomy is indicated for early-stage hallux rigidus with preserved joint space, not end-stage disease.

Question 6671

Topic: 8. Foot and Ankle

In a patient with progressive posterior tibial tendon dysfunction, the loss of the tendon's primary biomechanical function leads to a cascade of foot deformities. Which of the following best describes the primary normal action of the posterior tibial tendon during the stance phase of gait?

. Eversion of the subtalar joint and dorsiflexion of the ankle
. Inversion of the subtalar joint and locking of the transverse tarsal joint
. Plantarflexion of the first ray and unlocking of the transverse tarsal joint
. Dorsiflexion of the midfoot and stabilization of the medial column
. Eversion of the hindfoot and unlocking of the transverse tarsal joint

Correct Answer & Explanation

. Inversion of the subtalar joint and locking of the transverse tarsal joint

Explanation

Correct Answer: BThe posterior tibial tendon (PTT) is the primary dynamic stabilizer of the medial longitudinal arch. During the stance phase of gait, particularly during heel rise and push-off, the PTT actively inverts the subtalar joint. This inversion causes the axes of the talonavicular and calcaneocuboid joints (which together make up the transverse tarsal joint, or Chopart's joint) to become non-parallel. When these axes are non-parallel, the transverse tarsal joint "locks," converting the midfoot and forefoot into a rigid lever arm necessary for efficient forward propulsion. Loss of PTT function results in a failure to lock the transverse tarsal joint, leading to a flexible, unstable foot and the classic acquired flatfoot deformity.

Question 6672

Topic: 8. Foot and Ankle

A 70-year-old woman is undergoing a first metatarsophalangeal (MTP) joint arthrodesis for severe hallux rigidus and a failed prior bunionectomy. To optimize postoperative gait and function, what is the ideal position for fusion of the first MTP joint?

. 0-5 degrees of valgus, 0-5 degrees of dorsiflexion relative to the first metatarsal, and neutral rotation
. 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotation
. 20-25 degrees of valgus, 20-25 degrees of plantarflexion relative to the first metatarsal, and neutral rotation
. Neutral valgus, 30 degrees of dorsiflexion relative to the floor, and 10 degrees of pronation
. 10-15 degrees of varus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotation

Correct Answer & Explanation

. 10-15 degrees of valgus, 10-15 degrees of dorsiflexion relative to the floor, and neutral rotation

Explanation

Correct Answer: BThe success of a first MTP joint arthrodesis depends heavily on achieving the correct position of fusion. The ideal position is 10 to 15 degrees of valgus, 10 to 15 degrees of dorsiflexion relative to the floor (which equates to approximately 25 to 30 degrees of dorsiflexion relative to the longitudinal axis of the first metatarsal shaft), and neutral rotation. This position allows the hallux to clear the ground during the swing phase of gait, permits normal weight-bearing through the toe during push-off, and accommodates most standard footwear with a slight heel. Excessive dorsiflexion causes shoe wear problems and dorsal pain, while excessive plantarflexion leads to vaulting and interphalangeal joint arthritis.

Question 6673

Topic: Midfoot & Hindfoot
A 60-year-old woman presents with medial ankle pain. Examination reveals tenderness along the posterior tibial tendon, but she is able to perform a single-leg heel raise symmetrically. She has undergone 8 weeks of cast immobilization, taken nonsteroidal anti-inflammatory medications, and completed physical therapy without relief. What is the most appropriate next step in management?
. Flexor digitorum longus transfer and medial displacement calcaneal osteotomy
. Triple arthrodesis
. Tenosynovectomy and debridement of the posterior tibial tendon
. Subtalar arthrodesis
. Gastrocnemius recession alone

Correct Answer & Explanation

. Tenosynovectomy and debridement of the posterior tibial tendon

Explanation

This patient presents with Stage I posterior tibial tendon dysfunction (PTTD), characterized by tenosynovitis, normal tendon length, and the ability to perform a single-leg heel raise. The initial treatment for Stage I PTTD is conservative, including immobilization (cast or boot), orthotics, NSAIDs, and physical therapy. When conservative management fails after an adequate trial (typically 3-6 months), surgical intervention is indicated. For Stage I disease, tenosynovectomy and debridement of the posterior tibial tendon is the procedure of choice. Flexor digitorum longus (FDL) transfer and medial displacement calcaneal osteotomy are indicated for Stage II PTTD, where the tendon is elongated and the hindfoot is in a flexible valgus deformity (inability to perform a single heel raise). Triple arthrodesis is reserved for Stage III PTTD, which involves a rigid hindfoot valgus deformity.

Question 6674

Topic: 8. Foot and Ankle

In a patient with progressive posterior tibial tendon dysfunction, the spring ligament often becomes attenuated and fails. Which of the following best describes the primary anatomical attachments of the superomedial band of the spring ligament?

. Sustentaculum tali to the navicular tuberosity
. Calcaneal anterior process to the cuboid
. Medial malleolus to the talus
. Sustentaculum tali to the medial cuneiform
. Navicular to the medial cuneiform

Correct Answer & Explanation

. Sustentaculum tali to the navicular tuberosity

Explanation

Correct Answer: AThe spring ligament, or calcaneonavicular ligament complex, is a critical static stabilizer of the medial longitudinal arch. It consists of three bands: the superomedial, the medioplantar, and the inferoplantar bands. The superomedial band is the most important and most frequently torn or attenuated in posterior tibial tendon dysfunction (PTTD). It originates from the sustentaculum tali of the calcaneus and inserts onto the navicular tuberosity. It acts as a sling to support the talar head. Failure of the posterior tibial tendon places increased stress on the spring ligament, eventually leading to its failure and the characteristic peritalar subluxation seen in Stage II PTTD.

Question 6675

Topic: Forefoot

A 70-year-old active woman presents with severe pain with weightbearing over the first metatarsophalangeal (MTP) joint. She underwent a bunion correction 25 years ago. Radiographs demonstrate severe first MTP joint arthrosis with a prominent retained screw from the prior procedure. Conservative management has failed. Which of the following is the most reliable surgical option to provide long-term pain relief and functional improvement?

. First MTP joint arthrodesis
. Silicone implant arthroplasty
. Resection arthroplasty (Keller procedure)
. Cheilectomy
. First MTP total joint arthroplasty

Correct Answer & Explanation

. First MTP joint arthrodesis

Explanation

Correct Answer: AFirst MTP joint arthrodesis is the gold standard for the treatment of end-stage hallux rigidus and for the salvage of failed hallux valgus surgery. It provides reliable, long-term pain relief and restores the weightbearing function of the first ray. Silicone implant arthroplasty has historically been associated with high failure rates, silicone synovitis, and significant bone loss, making it a poor choice. A Keller resection arthroplasty involves resecting the base of the proximal phalanx; while it relieves pain, it destabilizes the joint, leading to a "cock-up" deformity and transfer metatarsalgia, and is generally reserved for low-demand, elderly patients. Cheilectomy is indicated for early-stage hallux rigidus without severe joint space narrowing. Total joint arthroplasty of the first MTP has higher complication and revision rates compared to arthrodesis.

Question 6676

Topic: Midfoot & Hindfoot

A 55-year-old male with poorly controlled diabetes presents with a red, warm, and swollen right foot. He has no open ulcers. Radiographs reveal fragmentation, periarticular debris, and subluxation of the tarsometatarsal joints. Which of the following is the most appropriate initial management?

. Total contact casting and non-weight bearing
. Intravenous antibiotics and surgical debridement
. Primary arthrodesis of the midfoot
. Below-knee amputation
. Corticosteroid injection into the affected joints

Correct Answer & Explanation

. Total contact casting and non-weight bearing

Explanation

The patient has an acute (Eichenholtz Stage 1) Charcot arthropathy. The mainstay of initial treatment is offloading and immobilization, typically achieved with a total contact cast, to prevent further deformity while the acute inflammation subsides.

Question 6677

Topic: 8. Foot and Ankle

A 28-year-old male sustains a purely ligamentous Lisfranc injury. Weight-bearing radiographs demonstrate 4 mm of diastasis between the medial cuneiform and the base of the second metatarsal. What is the most widely supported surgical treatment for this purely ligamentous injury?

. Closed reduction and percutaneous Kirschner wire fixation
. Open reduction and internal fixation with transarticular screws
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
. Suture button suspensionplasty alone
. Conservative management with non-weight-bearing cast for 8 weeks

Correct Answer & Explanation

. Primary arthrodesis of the first, second, and third tarsometatarsal joints

Explanation

Multiple studies demonstrate that primary arthrodesis of the medial column (1st, 2nd, and 3rd tarsometatarsal joints) yields better functional outcomes and lower revision rates than ORIF for purely ligamentous Lisfranc injuries.

Question 6678

Topic: 8. Foot and Ankle

A 30-year-old man sustains an axial load to a plantarflexed foot. Radiographs show widening between the 1st and 2nd metatarsal bases with a 'fleck sign'. The primary ligament disrupted in this injury directly connects which two osseous structures?

. Medial cuneiform to the base of the second metatarsal
. First cuneiform to the base of the first metatarsal
. Middle cuneiform to the base of the second metatarsal
. Cuboid to the base of the fourth metatarsal
. Navicular to the medial cuneiform

Correct Answer & Explanation

. Medial cuneiform to the base of the second metatarsal

Explanation

The Lisfranc ligament is a strong interosseous ligament that connects the medial cuneiform to the base of the second metatarsal. Its disruption is the hallmark of a Lisfranc injury, often indicated by the pathognomonic 'fleck sign' (an avulsion fracture).

Question 6679

Topic: 8. Foot and Ankle

A 22-year-old male athlete sustains an axial load to a plantarflexed foot. Weight-bearing radiographs show 3 mm of widening between the base of the first and second metatarsals with a "fleck sign". MRI confirms a purely ligamentous Lisfranc injury. What is the most widely supported definitive surgical management for this specific injury pattern?

. Closed reduction and percutaneous K-wire fixation
. Open reduction and rigid internal fixation (ORIF) with transarticular screws
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
. Dorsal bridge plating without joint preparation
. Cast immobilization and non-weight bearing for 12 weeks

Correct Answer & Explanation

. Primary arthrodesis of the first, second, and third tarsometatarsal joints

Explanation

For purely ligamentous Lisfranc injuries, primary arthrodesis of the medial column has been shown to result in better functional outcomes and lower reoperation rates compared to ORIF. This is due to the poor healing potential of the torn Lisfranc ligament complex.

Question 6680

Topic: 8. Foot and Ankle

A 55-year-old male with a 15-year history of poorly controlled type 2 diabetes mellitus presents for a routine foot examination. The physician uses a Semmes-Weinstein monofilament to assess for loss of protective sensation. Which of the following specific monofilament sizes and corresponding buckling forces represents the threshold for loss of protective sensation?

. 4.17 monofilament (1 gram of force)
. 5.07 monofilament (10 grams of force)
. 6.10 monofilament (75 grams of force)
. 3.61 monofilament (0.4 grams of force)
. 4.56 monofilament (4 grams of force)

Correct Answer & Explanation

. 5.07 monofilament (10 grams of force)

Explanation

Correct Answer: BThe 5.07 Semmes-Weinstein monofilament, which buckles at 10 grams of force, is the standard screening tool for loss of protective sensation in diabetic patients. Inability to feel this monofilament indicates a loss of protective sensation, placing the patient at high risk for neuropathic ulcers and Charcot arthropathy. The 4.17 monofilament (1 gram) is used to test normal sensation, while the 6.10 monofilament (75 grams) tests for deep pressure sensation.

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