Foot and ankle structured oral questions6: Hallux valgus

EXAMINER: Please have a look at these clinical photographs and tell me what you see. (Figures 4.7 and 4.8.)

CANDIDATE: These show a frontal view of a pair of feet and an oblique view of the left foot. There is hallux valgus with the hallux over-riding the second toes. I can only count three lesser toes on the left foot and there is a scar in the webspace lateral to the hallux. The toenails appear friable and there is some excoriation around the lesser toes on the right foot. There is also a small area of scab on the dorsum of the right foot. I don’t see any scars on the right foot but I think there is also a medial longitudinal scar over the left metatarsophalangeal joint.

EXAMINER: Absolutely. This 65-year-old lady had her left second toe removed some years ago for a presentation similar to that which she now has on the right. Her left-sided symptoms have also recurred. How would you assess her further?

Figure 4.7 Anteroposterior (AP) view of hallux valgus.

Figure 4.8 Oblique view of hallux valgus.

CANDIDATE: A detailed history should be obtained, looking to clarify the main source of her symptoms. Can I ask what symptoms she has?

EXAMINER: What do you think they are likely to be?

CANDIDATE: I would expect she has pain from her bunions and toes caused by rubbing on footwear and each other. I would be concerned to find out about symptoms suggestive of arthritic change at the MTP joint or metatarsalgia of the lesser rays.

EXAMINER: Let’s say she has all these symptoms to varying degrees. Tell me about your further assessment.

CANDIDATE: I would complete the history, including questioning about relevant conditions such as diabetes, inflammatory arthritis, vascular disease and neuropathy, and proceed to examination. I would examine the gait and the posture of the weighted foot as hallux valgus is often associated with a planus foot. I would palpate for areas of tenderness, paying particular attention to the hallux MTP joint and lesser metatarsal heads. I would assess the degree of active and passive correction possible and the range of movement of the involved joints and look for gastrocnemius tightness. I would also perform a grind test to assess pain from loading the MTP joint. Neurovascular status must also be assessed.

EXAMINER: You spoke about assessing the range of movement of the involved joints. Can you be more specific?

CANDIDATE: I would want to assess the range of plantarflexion and dorsiflexion of the hallux MTP joint. It is also important to assess the movement at the first tarsometatarsal joint as excessive mobility here will influence surgical options.

EXAMINER: Okay, we might come back to that. Outline the value of plain radiographs in the management of hallux valgus.

CANDIDATE: I would routinely obtain weightbearing AP, oblique and lateral radiographs of the foot. This would allow me to objectively measure the angles, assess uncovering of the sesamoids and look for evidence of arthritic change.

EXAMINER: Keep going. What angles?

CANDIDATE: I would measure the intermetatarsal angle, hallux valgus angle and the distal metatarsal articular angulation.

EXAMINER: What is the normal range of these angles and how would these influence your management?

CANDIDATE: The intermetatarsal angle is normally less than 9. The hallux valgus angle should be less than 15. The distal metatarsal articular angle is normally a maximum of 15 from perpendicular to the axis of the first metatarsal. The degree of deformity largely determines the surgical management.

EXAMINER : If this lady had an intermetatarsal angle of 15 on the right with a hallux valgus angle of 35 and minimal passive correction of the hallux, what surgery would you plan?

CANDIDATE: If the first tarsometatarsal joint is normal, I would plan a scarf osteotomy combined with a lateral release and an Akin osteotomy of the proximal phalanx if necessary.

EXAMINER: Why would you choose a scarf osteotomy?

CANDIDATE : It is a very versatile procedure with stable fixation allowing postoperative mobilization without a cast. It maintains length of the metatarsal but allows translation, angulation and depression of the metatarsal head as necessary.

It can also be used to shorten or even lengthen the metatarsal.¹

EXAMINER : How would you secure the osteotomy?

CANDIDATE: With two headless compression screws.

EXAMINER: Why not use a simpler procedure such as a chevron or Mitchell osteotomy?

CANDIDATE: For the degree of deformity described, combined with the lack of passive correction of the hallux, I believe the correction that could be achieved with a distal osteotomy would be inadequate. A further disadvantage of a Mitchell osteotomy is that it produces shortening of the first metatarsal, which could lead to transfer metatarsalgia.

EXAMINER: For your proposed management, what complications would you discuss when seeking consent?

CANDIDATE : Firstly, I would advise that whilst early weightbearing is possible with a scarf osteotomy it takes up to a year for the foot to fully settle after such surgery but that typically 85% of patients are pleased with the outcome. I would advise a 1% risk of deep infection and a slightly higher risk of superficial infection. Recurrence is possible with time although the risk of this is greatest in adolescent cases. A minority of patients will have significant stiffness of the MTP joint afterwards and there can be sensory loss if the dorsomedial sensory nerve is injured. I would mention the possibility of hallux varus as a complication as this is difficult to treat. I would also mention the possibility of intraoperative and postoperative metatarsal fracture.

EXAMINER: How would you treat hallux varus?

CANDIDATE: A subtle varus may improve as the patient returns to normal foot wear. Whilst soft tissue procedures such as abductor hallucis and medial capsular release or transfer of a

slip of EHL are described for flexible deformity, arthrodesis of the first MTP joint is a reliable option in the presence of significant stiffness or arthrosis.

EXAMINER: So you have successfully treated this lady’s right foot and she is pleased with the result. Would you go ahead and do the same on the left?

CANDIDATE: No. The absence of the second toe predisposes to recurrence and I would propose arthrodesis of the hallux MTP joint.

EXAMINER: Thank you.

1. Barouk LS, Toullec ET. Use of scarf osteotomy of the first metatarsal to correct hallux valgus deformity. Techniques Foot Ankle Surg 2003;2(1):27–34.

Foot and ankle structured oral questions6: Hallux valgus

EXAMINER: Please have a look at these clinical photographs and tell me what you see. (Figures 4.7 and 4.8.)

CANDIDATE: These show a frontal view of a pair of feet and an oblique view of the left foot. There is hallux valgus with the hallux over-riding the second toes. I can only count three lesser toes on the left foot and there is a scar in the webspace lateral to the hallux. The toenails appear friable and there is some excoriation around the lesser toes on the right foot. There is also a small area of scab on the dorsum of the right foot. I don’t see any scars on the right foot but I think there is also a medial longitudinal scar over the left metatarsophalangeal joint.

EXAMINER: Absolutely. This 65-year-old lady had her left second toe removed some years ago for a presentation similar to that which she now has on the right. Her left-sided symptoms have also recurred. How would you assess her further?

Figure 4.7 Anteroposterior (AP) view of hallux valgus.

Figure 4.8 Oblique view of hallux valgus.

CANDIDATE: A detailed history should be obtained, looking to clarify the main source of her symptoms. Can I ask what symptoms she has?

EXAMINER: What do you think they are likely to be?

CANDIDATE: I would expect she has pain from her bunions and toes caused by rubbing on footwear and each other. I would be concerned to find out about symptoms suggestive of arthritic change at the MTP joint or metatarsalgia of the lesser rays.

EXAMINER: Let’s say she has all these symptoms to varying degrees. Tell me about your further assessment.

CANDIDATE: I would complete the history, including questioning about relevant conditions such as diabetes, inflammatory arthritis, vascular disease and neuropathy, and proceed to examination. I would examine the gait and the posture of the weighted foot as hallux valgus is often associated with a planus foot. I would palpate for areas of tenderness, paying particular attention to the hallux MTP joint and lesser metatarsal heads. I would assess the degree of active and passive correction possible and the range of movement of the involved joints and look for gastrocnemius tightness. I would also perform a grind test to assess pain from loading the MTP joint. Neurovascular status must also be assessed.

EXAMINER: You spoke about assessing the range of movement of the involved joints. Can you be more specific?

CANDIDATE: I would want to assess the range of plantarflexion and dorsiflexion of the hallux MTP joint. It is also important to assess the movement at the first tarsometatarsal joint as excessive mobility here will influence surgical options.

EXAMINER: Okay, we might come back to that. Outline the value of plain radiographs in the management of hallux valgus.

CANDIDATE: I would routinely obtain weightbearing AP, oblique and lateral radiographs of the foot. This would allow me to objectively measure the angles, assess uncovering of the sesamoids and look for evidence of arthritic change.

EXAMINER: Keep going. What angles?

CANDIDATE: I would measure the intermetatarsal angle, hallux valgus angle and the distal metatarsal articular angulation.

EXAMINER: What is the normal range of these angles and how would these influence your management?

CANDIDATE: The intermetatarsal angle is normally less than 9. The hallux valgus angle should be less than 15. The distal metatarsal articular angle is normally a maximum of 15 from perpendicular to the axis of the first metatarsal. The degree of deformity largely determines the surgical management.

EXAMINER : If this lady had an intermetatarsal angle of 15 on the right with a hallux valgus angle of 35 and minimal passive correction of the hallux, what surgery would you plan?

CANDIDATE: If the first tarsometatarsal joint is normal, I would plan a scarf osteotomy combined with a lateral release and an Akin osteotomy of the proximal phalanx if necessary.

EXAMINER: Why would you choose a scarf osteotomy?

CANDIDATE : It is a very versatile procedure with stable fixation allowing postoperative mobilization without a cast. It maintains length of the metatarsal but allows translation, angulation and depression of the metatarsal head as necessary.

It can also be used to shorten or even lengthen the metatarsal.¹

EXAMINER : How would you secure the osteotomy?

CANDIDATE: With two headless compression screws.

EXAMINER: Why not use a simpler procedure such as a chevron or Mitchell osteotomy?

CANDIDATE: For the degree of deformity described, combined with the lack of passive correction of the hallux, I believe the correction that could be achieved with a distal osteotomy would be inadequate. A further disadvantage of a Mitchell osteotomy is that it produces shortening of the first metatarsal, which could lead to transfer metatarsalgia.

EXAMINER: For your proposed management, what complications would you discuss when seeking consent?

CANDIDATE : Firstly, I would advise that whilst early weightbearing is possible with a scarf osteotomy it takes up to a year for the foot to fully settle after such surgery but that typically 85% of patients are pleased with the outcome. I would advise a 1% risk of deep infection and a slightly higher risk of superficial infection. Recurrence is possible with time although the risk of this is greatest in adolescent cases. A minority of patients will have significant stiffness of the MTP joint afterwards and there can be sensory loss if the dorsomedial sensory nerve is injured. I would mention the possibility of hallux varus as a complication as this is difficult to treat. I would also mention the possibility of intraoperative and postoperative metatarsal fracture.

EXAMINER: How would you treat hallux varus?

CANDIDATE: A subtle varus may improve as the patient returns to normal foot wear. Whilst soft tissue procedures such as abductor hallucis and medial capsular release or transfer of a

slip of EHL are described for flexible deformity, arthrodesis of the first MTP joint is a reliable option in the presence of significant stiffness or arthrosis.

EXAMINER: So you have successfully treated this lady’s right foot and she is pleased with the result. Would you go ahead and do the same on the left?

CANDIDATE: No. The absence of the second toe predisposes to recurrence and I would propose arthrodesis of the hallux MTP joint.

EXAMINER: Thank you.

1. Barouk LS, Toullec ET. Use of scarf osteotomy of the first metatarsal to correct hallux valgus deformity. Techniques Foot Ankle Surg 2003;2(1):27–34.