Complications

Question 1

AVN following chevron osteotomy

Answer 1

The artery most likely implicated in development of AVN of the first metatarsal head is the first dorsal metatarsal artery, which is fed by the nutrient artery. This is most likely to cause AVN if disrupted. The first dorsal metatarsal artery helps to form a significant extracapsular anastomosis that supplies approximately two-thirds of the metatarsal head.

Question 2

Contraction over time of skin grafts

Answer 2

The thinner the graft is, the more likely it is to contract. STSG will contract more than FTSG.

Question 3

Hyperplasia following 1st MTPJ implant

Answer 3

Traditionally, long term results in 1st MTP joint total implants have varied. Instability and synovitis are common complications with the Swanson implant. Fibrous hyperplasia is common and forms within medullary bone, impacting the hinges and increases likelihood for failure and need for removal. Insertion of the implant sizer allows for assessment of the fit, and directs appropriate bone resection and implant placement alignment.

Question 4

Intravascular lidocaine

Answer 4

Peak blood levels of lidocaine usually occur 10–25 minutes after injection. This is the point at which the toxic effects are most likely to be observed. The onset of symptoms is faster if accidental intravascular injection has occurred. The first symptoms and signs of local anaesthetic toxicity are usually neurological with numbness of the mouth and tongue. Shortly afterwards, there is the onset of tinnitus, confusion, seizures, and potentially coma.

Question 5

Toxic dose for lidocaine plain

Answer 5

Toxic dose for Lidocaine plain = 4.5mg/kg

Question 6

Toxic dose for lidocaine with epi

Answer 6

Lidocaine with epinephrine = 7mg/kg

Question 7

Toxic dose for marcaine plain

Answer 7

Marcaine plain = 3mg/kg

Question 8

Toxic dose of lidocaine plain for a 60 kg female

Answer 8

60kg x 4.5mg = 270mg. 270mg % (10mg/mL) = 27mL

Question 9

Most common complication of external fixation

Answer 9

Pin-tract infections are the most common complication, and an almost inevitable problem when using external fixation. If left untreated the infection may lead to pin loosening and instability of pin-bone construct.

Question 10

Most common complication following displaced talar neck fracture

Answer 10

Subtalar joint arthritis would be the single most likely complication in an isolated subtalar joint dislocation. “Peritalar stiffness and arthritis commonly occur after both talar neck and talar body fractures. Subtalar joint arthritis occurs more frequently after talar neck fractures, with an incidence of 60–100%. Talar body fractures have increased rates of arthritis at the tibiotalar joint. Despite x-ray evidence of joint space narrowing in many patients, there is usually little need for secondary reconstructive procedures

Question 11

What does a distraction bone block arthrodesis achieve

Answer 11

TN subluxation, TT impingement, subtalar arthrosis
Does not address peroneal tendons directly
Subtalar joint arthritis would be the single most likely complication in an isolated subtalar joint dislocation. “Peritalar stiffness and arthritis commonly occur after both talar neck and talar body fractures. Subtalar joint arthritis occurs more frequently after talar neck fractures, with an incidence of 60–100%. Talar body fractures have increased rates of arthritis at the tibiotalar joint. Despite x-ray evidence of joint space narrowing in many patients, there is usually little need for secondary reconstructive procedures

Question 12

What does a distraction bone block arthrodesis achieve

Answer 12

TN subluxation, TT impingement, subtalar arthrosis
Does not address peroneal tendons directly
Subtalar joint arthritis would be the single most likely complication in an isolated subtalar joint dislocation. “Peritalar stiffness and arthritis commonly occur after both talar neck and talar body fractures. Subtalar joint arthritis occurs more frequently after talar neck fractures, with an incidence of 60–100%. Talar body fractures have increased rates of arthritis at the tibiotalar joint. Despite x-ray evidence of joint space narrowing in many patients, there is usually little need for secondary reconstructive procedures

Question 13

Peroneal tendons following DIACF

Answer 13

Peroneal tendonitis is typically seen following non surgical management of displaced calcaneal fractures. The articular surface is not reduced and the heel remains shortened and widened, with the talus being dorsiflexed. The lateral wall, being displaced, leads to peroneal impingement/irritation.

Question 14

Talar neck fracture blood supply

Answer 14

The image shown is a type 3 Hawkins fracture. The deltoid branch of the posterior tibial artery; supplies up to 1/2 of the medial aspect of the talar body. Often, it is the deltoid artery that is the only remaining blood supply to the talus in these injuries. It is vitally important to preserve the deltoid ligament in order to avoid avascular necrosis.

Question 15

Risk of AVN following talar neck fracture

Answer 15

The extent of initial fracture displacement/dislocation, is related to the incidence of avascular necrosis of the talus. The greater the fracture displacement, the higher the probability the blood supply to the talus has been compromised; which then will increase the likelihood of avascular necrosis developing.

Question 16

Rates of nonunion for the 3 joints in a triple arthrodesis

Answer 16

The overall nonunion rate for triple arthrodesis in this series was 29.9% (47/157). The nonunion rate of the talonavicular joint was 20.4% (32/157); the nonunion rate of the calcaneocuboid joint was 17.2% (27/157); and the nonunion rate of the subtalar joint was 8.9% (14/157)

Question 17

Structure at risk during gastroc recession

Answer 17

The sural nerve should always be protected during a gastrocnemius recession. “It is generally safe to place the posterolateral incision more than 14cm above the calcaneal tuberosity to avoid the sural nerve if surgeons plan to use a posterolateral incision for endoscopic recession

Question 18

Gustilo Anderson Classification

Answer 18

Type I: simple fracture patterns with wounds less than 1 cm
Type II: simple fracture pattern or mildly comminuted with wound 1-10 cm
Type IIIA: significant soft tissue injury that requires skin graft
Type IIIB: significant soft tissue injury that requires flap coverage
Type IIIC: significant soft tissue injury with arterial compromise requiring vascular repair

Question 19

Increased risk of nonunion in talar neck fracture

Answer 19

The deltoid artery located within the deep deltoid provides blood supply to the deltoid ligament. Care should be taken to preserve the deep deltoid as often this may be the only remaining blood supply to the body with a talar neck fracture.

Question 20

Contraction of skin grafts

Answer 20

The thinner the graft is, the more likely it is to contract. STSG will contract more than FTSG.

Question 21

Hawkins classification

Answer 21

Hawkins I: Nondisplaced 0-13% chance of AVN
Hawkins II: Subtalar dislocation 20-50% chance of AVN
Hawkins III: Subtalar and tibiotalar dislocation 20-100% chance of AVN
Hawkins IV: Subtalar, tibiotalar, and talonavicular dislocation 70-100% chance of AVN

Question 22

Osseous equinus following ankle arthrodesis

Answer 22

During an ankle fusion, the ankle must be positioned at 90 degrees. Often times, the surgeon will misinterpret mid foot extension as a form of ankle dorsiflexion, and this may lead to improper ankle fixation at time of hardware placement. Surgeons should have fluoroscopic evaluation during positioning and fixation.

Question 23

Hammer toes

Answer 23

Flexor stabilization. This is the most common cause of hammertoes, occurring in a pronated foot type when the flexor digitorum longus or flexor digitorum brevis gains a mechanical advantage over the interossei muscles. Due to the decreased action of the interossei, the flexors contract earlier and longer in an effort to stabilize the toe.
Flexor substitution. Least common cause where the flexors gain an advantage over the interossei. This usually occurs when the achilles tendon is weak and the other flexors compensate by contracting earlier and longer.
Extensor substitution. This occurs in the swing phase of gait rather than the stance phase like the other two scenarios. The EDL gains an advantage over the lumbricales.
In the scenario described in the MCQ, the FDL has become mechanically weak, thereby allowing for the EDL to gain mechanical advantage over the lumbricales leading to extensor substitution and a cock up hallux.

Question 24

AVN following chevron osteotomy

Answer 24

The artery most likely implicated in development of AVN of the first metatarsal head is the first dorsal metatarsal artery, which is fed by the nutrient artery. This is most likely to cause AVN if disrupted. The first dorsal metatarsal artery helps to form a significant extracapsular anastomosis that supplies approximately two-thirds of the metatarsal head.

Question 25

Hyperplasia following 1st MTPJ implant

Answer 25

Traditionally, long term results in 1st MTP joint total implants have varied. Instability and synovitis are common complications with the Swanson implant. Fibrous hyperplasia is common and forms within medullary bone, impacting the hinges and increases likelihood for failure and need for removal. Insertion of the implant sizer allows for assessment of the fit, and directs appropriate bone resection and implant placement alignment.