EXAMINER: What approach do you use for THA?

CANDIDATE: The posterior approach to the hip joint.

COMMENT: This is probably the most common approach you will be asked to describe. You could mention any of the hip approaches, but the most common approaches used in the UK are the posterior and the anterolateral (Hardinge).

Talk about the approach that you know and use routinely. If you try to describe something that you have only read in a book, you will probably struggle to explain the details, including any technical tips or how to enlarge the approach. Read up on your favoured approach beforehand, especially the neurovascular intervals and structures at risk.

EXAMINER: What approach would you use for a THA operation done for fracture neck of femur?

CANDIDATE: The posterior approach. I am aware that many surgeons use an anterolateral approach for this indication to reduce the risk of dislocation. The NICE guidance for hemiarthroplasty prefers an anterolateral over a posterior approach, but no such differentiation is suggested with THA. I would use a posterior approach in this situation, as this is the approach I am more familiar with using in THA.

COMMENT: Candidates should be able to describe some rationale in using their preferred approach for the procedure.

EXAMINER: Describe the approach from skin, fat, fascia, bursa, and muscular interval if relevant to the joint.

EXAMINER: Some surgeons do not routinely detach the piriformis.

CANDIDATE: I generally do so unless I am particularly worried about instability – but I would go anterolaterally if this was the case.

COMMENT: Candidates may be asked origins/insertions and nerve supply of the short external rotator muscles hip.

EXAMINER: What nerve is at risk in each approach and when?

CANDIDATE: Posterior: sciatic nerve during approach. Femoral nerve during retraction/exposure of the anterior acetabulum. Obturator nerve: during inferior acetabulum retraction.

Lateral: Superior gluteal nerve (3–5 cm above the upper border of the greater trochanter) during the approach through the abductors, femoral nerve, artery and vein (retractors); transverse branch of lateral circumflex femoral artery (as vastus lateralis is mobilized).

EXAMINER: What is the consequence of damage in terms of sensory loss, weakness?

CANDIDATE: Sciatic – most commonly affects peroneal branch; therefore, foot drop and sensory loss dorsum of the foot.

Femoral – weak knee extension and loss of sensation over the medial border of the leg and foot.

Superior gluteal nerve – abductor weakness, Trendelenburg gait.

COMMENT: You must know your peripheral nerve lesions and sensory dermatomes for many different topics, e.g. spinal injuries, ATLS assessment, brachial plexus.

EXAMINER: Which approach is more extensile for revision hip surgery?

CANDIDATE: The posterior.

COMMENT: It is acceptable to mention another approach if you can justify it.

EXAMINER: What manoeuvres can be performed to improve exposure of the acetabulum?

CANDIDATE: Release piriformis, anterior capsule, reflected head of rectus femoris, psoas tendon.

EXAMINER: What manoeuvres can be performed to facilitate removal of cement and/or a femoral stem which are difficult to remove?

CANDIDATE: Extended trochanteric osteotomy.

Trochanteric osteotomy/slide.

Window in femur.

EXAMINER: Describe how you would perform an ETO.

CANDIDATE: Ideally preoperative planning in which the osteotomy length is determined from the tip of the greater trochanter.

I would expose the lateral femur by elevating the vastus lateralis off the linea aspera with due care to identify the perforating vessels. Then mark out the osteotomy line using cautery planning for a posterior to anterior longitudinal cut and a short distal transverse cut. Then two or three osteotomes are used to elevate the osteotomy fragment with a muscular hinge anteriorly. I use a prophylactic cerclage cable distal to the osteotomy site.

EXAMINER: What are your indications for ETO?

EXAMINER: A 5-year-old boy presents to A&E with a 2-day history of fevers, off legs, c/o painful hip and knee. This is his X-ray. After taking a history and examination, what tests would you perform (likelihood of hip sepsis)?

CANDIDATE: FBC, CRP, ESR, USS, MRI.

COMMENT: Hip sepsis in children is a common question at several points in the exam and needs to be known well. There are studies that have produced prediction of the likelihood of septic arthritis depending on blood markers and clinical features. If the viva station is progressing well it should be relatively easy to throw in Kocher’s criteria for a child with a painful hip:

EXAMINER: Describe this radiograph (Figure 19.3).

CANDIDATE: It is an X-ray of the right forearm of an adult. There are transverse fractures of the mid shaft of both radius and ulna. They are completely displaced.

COMMENT: You must be able to quickly and concisely describe a fracture as if you were talking to your consultant on the end of a phone and so he can easily imagine the fracture pattern.

EXAMINER: How would you describe the displacement concisely?

CANDIDATE: They are off-ended.

EXAMINER: What is the generally accepted surgical treatment for this injury?

CANDIDATE: Plating of both bones with dynamic compression plates.

EXAMINER: If you were to approach the fractured radius anteriorly, how would you do it?

COMMENT: The anterior approach to the radius was first described by Henry and his name is usually associated with it. Henry’s approach can be divided into a proximal internervous plane between the brachioradialis muscle (radial nerve) and the pronator teres (median nerve) or a distal approach between brachioradialis (radial nerve) and the flexor carpi radialis muscle (FCR) (median nerve). The internervous planes are the same throughout the forearm, but the muscles encountered are different proximally and distally.

The deep surgical dissection is divided into thirds (proximal, middle and distal third).

CANDIDATE: Landmarks: Biceps tendon, brachioradialis (part of the mobile wad), lateral epicondyle of humerus and styloid process of radius.

Incision: Incise the skin over the FCR aiming towards the biceps insertion. Develop the plane between the brachioradialis (radial nerve) and the FCR (median nerve) distally and retract the FPL.

I would approach the distal radius through the bed of the FCR. The sheath of FCR is incised and the tendon freed and retracted in an ulnar direction to protect the median nerve. Next, the floor of the FCR sheath is incised. Directly beneath the sheath is the belly of the flexor pollicis longus (FPL). The muscle is bluntly swept to the side to expose the deep fibres of the pronator quadratus. The radial portion of the pronator quadratus is incised and dissected off the distal radius using a combination of sharp dissection and a periosteal elevator with an L-type incision. A small cuff of tissue is left for later repair. Often there is partial disruption by the fracture fragments in high-energy injuries.

COMMENT: The candidate for whatever reason has described the anterior volar approach to the distal radius. The radiograph demonstrates a mid-third radius fracture and as such the examiner should have guided the candidate back onto the mid-third radius approach.

The superficial muscular dissection is similar for all three parts of Henry’s anterior approach: the interval between the brachioradialis (mobile wad) and the flexor carpi radialis (FCR) muscle. The radial artery lies deep to the brachioradialis in the middle part of the forearm and between the tendons of the brachioradialis and the FCR distally. It is identified by its two venae comitantes that run alongside it.

The middle third of the radial shaft is covered by the pronator teres (PT) and the flexor digitorum superficialis (FDS) muscle. The arm is pronated to expose the insertion of the PT onto the lateral radial shaft. The insertion is detached, and the muscle stripped off in an ulnar direction, which also detaches the origin of the FDS.

EXAMINER: How would you position the patient?

CANDIDATE: I would position the patient supine with an arm board and upper arm tourniquet. I would elevate the arm but not exsanguinate it so as to keep the veins engorged. This helps with identification of the venae comitantes of the radial artery. I would perform a surgical time-out before inflating the tourniquet, undertaking skin preparation and draping.

COMMENT: Go through a set standard routine for each approach. This question is about how you set the patient up for surgery. Ideally, the candidate should have initially mentioned this.

EXAMINER: What do you mean by a surgical time-out?

CANDIDATE: This is the final step before the start of the surgical procedure where the patient, surgical procedure and side/site are reviewed by the surgical team.

COMMENT: This is a classic approach and anecdotally candidates have been failed for not knowing it! Some approaches have quirks or peculiarities, and this is one of them – the need to change the position of the limb depending on the fracture location.

Try to have a mental picture of the origins and insertions on the radius from proximal to distal when describing this approach.

EXAMINER: How would you extend the exposure proximally?

CANDIDATE: This approach can be extended across the elbow into an anterolateral approach to the humerus, but this is rarely required.

EXAMINER: How would you extend the exposure distally?

CANDIDATE: The approach can be extended distally into the wrist with a carpal tunnel-type incision.

EXAMINER: What are the structures at risk (SAR)?

CANDIDATE: PIN: this travels through the body of supinator and can be damaged when exposing the proximal third of the radial shaft. Fully supinate the forearm when dissecting the supinator muscle off the radius as this moves the PIN away from the operative field. A subperiosteal dissection stripping the muscle from bone rather than splitting the muscle thereby leaving the PIN in the substance of the muscle. Ensure full supination and avoid using a retractor on the posterior radial neck to avoid potential injury.

Superficial radial nerve (SRN): this runs down the forearm underneath the brachioradialis muscle. It is vulnerable when the mobile wad of three is mobilized and retracted laterally. The nerve can be damaged with vigorous retraction. The SRN is notorious in developing a painful neuroma second to innocuous injury.

Radial artery: runs down the middle of the forearm under brachioradialis. A leash of vessels from the radial artery supply the brachioradialis and they need to be ligated in order to mobilize the brachioradialis. The radial artery is vulnerable during mobilization of the brachioradialis and is often retracted medially to expose the deeper muscular layers.