EXAMINER: This is a clinical photograph of a child (Figure 18.1) who tripped and fell, hurting his knee. He was seen in the A&E department and referred to your fracture clinic. Describe what you see. How would you approach him?

CANDIDATE: My approach is to take a detailed history, perform a thorough examination and order the appropriate investigations guided by my examination and provisional diagnosis. The left image shows a child standing with two crutches, wearing a knee splint on the left lower limb. The left leg is externally rotated and may be short. My first impression is that this child may have a slipped upper femoral epiphysis (SUFE).

EXAMINER: How can you confirm your diagnosis?

CANDIDATE: History, examination and radiological tests to confirm my diagnosis. History of previous pain in the hip before the fall is an important clue. He stands with crutches (if he has a slip, it is probably a stable type). Hip examination may reveal limited internal rotation or even obligatory external rotation on flexing the hip (Drehmann sign). I also request pelvis X-ray (AP and cross-table lateral views of both hips). I do not prefer frog lateral as it may worsen the severity in unstable slips; however, it is reasonable to request in a stable slip.

EXAMINER: This is his pelvis X-ray (Figure 18.2). What can you see?

CANDIDATE: This is a plain X-ray of the pelvis (AP view only) showing both hips. The most obvious abnormality is the slipped upper femoral (capital) epiphysis on the left side. The head remained in the socket while the neck moves anteriorly and superiorly. Trethowan’s sign is positive; a line (often referred to as Klein’s line) drawn on the superior border of the femoral neck on the AP view should pass through the femoral head. In SUFE, the line passes over the head rather than through the head. There are remodelling changes of the neck with sclerotic, smooth superior part of the neck and callus formation on the inferior border. This indicates the slip is not acute and has been subclinical for a while.

EXAMINER: What other radiological signs might you see in SUFE?

CANDIDATE: Several radiological signs are described to aid diagnosing SUFE (particularly subtle ones). These are not present in every case of SUFE, such as Trethowan’s sign that I just mentioned; widening and irregularity of the growth plate (early sign); decreased epiphyseal height as the head slipped posteriorly behind the neck; remodelling changes of the neck and increased distance between the teardrop and the femoral neck metaphysis. Capener’s sign: normally, on the AP pelvis the posterior acetabular margin cuts across the medial corner of the upper femoral metaphysis. In SUFE, the entire metaphysis is lateral to the posterior acetabular margin. Steel’s blanch sign, which is a crescent shape dense area in the metaphysis due to superimposition of the neck and the head.

EXAMINER: What if this child’s X-ray was normal?

CANDIDATE: Normal X-ray does not exclude SUFE (it may be in the preslip stage); therefore, I would request an MRI scan but also, I would consider other possible diagnoses.

EXAMINER: Can you grade the severity?

CANDIDATE: I measure the severity using either Wilson grading on the AP views or the Southwick angle on the lateral views. I consider that this is a severe slip as the head almost slipped by more than two-thirds of the physis width.

EXAMINER: Can you draw for me how these two classifications measure the severity of the slip?

CANDIDATE: Radiological grading of the severity of the slip has been based on either the degree of displacement of the head relative to the neck (Wilson), or by degree of the angulation of the head relative to the shaft (Southwick). Wilson recognized three grades on the AP view: mild slip (grade I) is one where the displacement of the head as a proportion of neck (physis) width is less than a third, moderate slip (grade II), displacement is between a third and a half of the neck width and severe slip (grade III) has displacement of greater than half of the neck width (Figure 18.3).

Southwick graded the severity on the frog lateral view by measuring the Southwick angle, which is the difference between the lateral epiphyseal shaft angle of the slipped and the non-slipped sides (Figure 18.4). Mild slip (grade I) has an angle difference of less than 30°, moderate slip (grade II) has an angle difference of between 30° and 50° and severe slip has a difference of over 50°. If both sides slipped, Southwick angle is calculated by subtracting 12° from the corresponding lateral epiphyseal shaft angle.

EXAMINER: You mentioned that the slip is stable. Why?

CANDIDATE: Randall Loder [2] classified SUFE into two types:

1. 
   

   I. Stable slip: child is able to weight bear.

   
   
2. 
   

   II. Unstable slip: child is not able to weight bear on the affected side even with crutches.

This classification has been shown to be of prognostic value. The risk of AVN is high in an unstable SUFE and low in a stable one. In Loder’s original paper the AVN rate was 47% in unstable SUFE and 0% in stable ones. Similar findings were shown in other centres [3,4].

There has been some confusion about the exact meaning of ‘able to weight bear’ in Loder’s original paper. ‘Ambulation’ may be a better term to describe slip stability. So, to me the slip is unstable if the child cannot weight bear and ambulate even with crutches. This child is standing and even if he does not put weight on the affected limb, there must be enough stability to allow him to stand. That is why I said it is a stable slip.

EXAMINER: How would you treat this child?

CANDIDATE: This child has grade III stable slip. My options are:

EXAMINER: Do you think you can pin this SUFE?

CANDIDATE: Yes, although it will not be easy and the worse the deformity is the more difficult the pinning in situ will be.

EXAMINER: Take me though how you would pin it.

CANDIDATE: Before I perform any operation, I will make sure that my patient is as fit as can be for surgery. I review their health records, investigations and obtain an informed consent for surgery. I will make sure that all the required equipment and implants are available. The operation is done under general anaesthetic (GA). Intravenous antibiotic is given at induction.

The patient is positioned supine on a fracture table (without traction). The other limb can be placed in abduction or flexed and abducted on stirrup to allow for imaging. Optimum visualization of the femoral head before the procedure is essential.

(In bilateral stable slip, a radiolucent table is preferred over the fracture table because it reduces the chance of worsening the contralateral slip by overenthusiastic positioning. This also reduces the time for re-positioning and re-draping the contralateral side. The stability is usually adequate to obtain a lateral view of the femoral neck by gentle flexion of the hip.)

The trajectory of my screw is identified and marked using a free guide wire placed on the skin overlying the proximal part of the femoral neck and head, crossing the physis in a perpendicular fashion in the AP and lateral views (Figure 18.5).

The guide pin is advanced freehand where the lines intersect through the soft tissues to engage the anterolateral femoral cortex. The position and angulations of the guide pin are adjusted under fluoroscopic guidance, to obtain the proper alignment before the guide pin is advanced into the bone. The entry point is usually quite anterior. It is essential to screen the hip to ensure there is no protrusion of the guide pin in the joint; particularly in the blind spot (Figure 18.6). For unstable slips, a second guide wire is useful to provide some rotational stability and can be used for the insertion of a second cannulated screw if desired.

After the appropriate screw length has been determined, the femoral neck and epiphysis is drilled using the cannulated instruments while periodically checking that the guide wire position is not advancing into the hip.

I prefer to use a 7.3- or 6.5-mm fully threaded, reversed cutting cannulated screw. The screw position should be carefully checked (using the withdrawal technique) to ensure there is no protrusion. If available, 3D C-arm is valuable for this purpose. Several other methods have been proposed for the same reason, but none is without limitations.

The patient is allowed touch weight-bearing with the use of crutches and gradually advances to full weight-bearing as tolerated. Follow-up is until physeal closure.

EXAMINER: Would you pin the other side?

CANDIDATE: I would consider pinning the other side in the following situations:

1. 
   

   1. Age of the child (< 10 years is associated with a higher risk of bilaterality).

   
   
2. 
   

   2. Slips associated with renal osteodystrophy and endocrine disorders (a high incidence of bilaterality approaching 95%).

   
   
3. 
   

   3. Poor compliance of the child and family.

   
   
4. 
   

   4. The nature of the current slip (a very bad slip occurring over a very short period of time may justify pinning the other side).

The quoted risk of contralateral slip varies from 18% to 60%. Prophylactic PIS is not devoid of risk and should be weighed against the benefit. The proponents and opponents have some evidence to support their views [5].

Some radiological markers have been proposed to aid decision-making about pinning the other asymptomatic side in patients with SUFE, such as the posterior sloping angle and the modified Oxford bone age [6,7]. Both of these markers are not perfect and do not have 100% positive or negative predictive value. I would have a low threshold to prophylactically pin the other side if the posterior sloping angle is more than 14° as research has shown that the risk of contralateral slip would be around 83%.

EXAMINER: Can you draw the posterior slip angle?

CANDIDATE: The posterior sloping angle (PSA) is measured by a line (A) from the centre of the femoral shaft through the centre of the metaphysis; a second line (B) is drawn from one edge of the physis to the other, which represents the angle of the physis. Where lines A and B intersect, a third line (C) is drawn perpendicular to line A. The PSA is the angle formed by lines B and C posteriorly, as illustrated in Figure 18.7.

EXAMINER: This is a clinical photograph of the elbow of a 5-year-old child who fell off a monkey bar (Figure 18.8). How would you manage this child?

CANDIDATE: The photograph shows wrist and elbow swelling, deformity and bruises. There may be skin puckering in front of the elbow. This child most likely has wrist and supracondylar fractures of the humerus (SCH#).

I always follow the ATLS protocols in assessing and managing traumatic injuries in children. Primary survey, then secondary survey and followed by AMPLE history. AMPLE stands for Allergies, Medication, Past medical history, Last food and drinks and Events around the accident.

EXAMINER: You perform primary and secondary surveys and find that this is an isolated upper limb injury.

CANDIDATE: Then I perform a thorough assessment of that limb. Optimum analgesia is extremely helpful to calm the child and makes my assessment pleasant. I look for obvious swelling, bruises, wounds, colour of the hands and fingers, etc. in that limb. I feel for skin temperature, pulses and tenderness. I assess the movement of the joints that are not involved to ensure that there are no unexpected problems. I would not move the elbow joint at this stage as it is expected to be painful. I assess the neurovascular status of the limb using special tests to test for nerve injuries.

EXAMINER: You find the hand warm and relatively well perfused but there was no radial pulse.

CANDIDATE: What about the neurological status?

EXAMINER: The child was not cooperative and you could not assess him optimally despite your best effort.

CANDIDATE: This is not an uncommon scenario. I would document this accurately (i.e. warm hand with no radial pulse) and I could not assess his neurological status (because of the pain and the lack of cooperation). I would like to confirm the diagnosis by requesting an X-ray.

EXAMINER: This was his X-ray.

CANDIDATE: The radiograph confirms my thoughts that this child has supracondylar humeral and distal radius fractures. Both are displaced. The supracondylar humerus fracture is an extension type (Gartland type III) injury with the distal fragment displaced posteriorly and rotated externally. It is not very clear from the X-ray, but there may be some comminution of the lateral column.

This is a limb-threatening injury and requires an immediate intervention. I would like to take the patient to theatre to reduce and stabilize the fracture. A vascular surgeon or a plastics surgeon (with microvascular skills) must be consulted before taking patients to theatre in case hand perfusion becomes worse after the reduction.

EXAMINER: How did Gartland classify these fractures?

CANDIDATE: Gartland classified this fracture into three types: Type I (undisplaced), type II angulated and type III complete displacement. The classification has undergone several modifications as more knowledge developed.

EXAMINER: How do you fix this fracture?

CANDIDATE: Preoperative planning and thoughtful preparation are key to successful outcome. I obtain an informed consent for surgery. I inform theatre about the child and the urgency of surgery. I liaise with my anaesthetist and vascular colleagues. The fracture pattern is extension type (Gartland type III), there may be some comminution. There is significant elbow swelling and there may be tethering. There is a wrist fracture distally which complicates things further. The risk of compartment syndrome is high. I still think closed reduction and percutaneous pinning (using two or three 2-mm K-wires) will be successful; however, an open reduction may become necessary.

After the WHO check, the child will have a GA and IV antibiotic. I position the child supine on the operating table and his hand is stretched on a hand table. The child’s head should be placed in a position close to the hand table, so it will not fall off the main table. The C-arm should come parallel to the main table to allow viewing the AP and lateral of the elbow without changing the elbow position.

I will gently check how easily I can reduce both fractures. Reduction is usually achieved by a gentle traction in line with the humerus, with the elbow in slight flexion. Traction in full extension may cause tethering of neurovascular structures over the proximal fragment. I will use the mid-forearm part for applying the traction to avoid traction damage to the distal neurovascular structures crossing the wrist fracture. If the proximal fragment has pierced through the brachialis muscle, a ‘milking’ manoeuvre over the brachialis can help untethering of the muscle off the bone. Traction usually takes between 1 and 3 minutes to allow for the muscle to relax and the soft tissue to stretch. Successful traction should allow the visibility of the fracture without overlapping of the proximal and the distal fragments on the AP screening. Then medial or lateral translation is corrected by pushing the distal fragment medially or laterally. An important precaution here is not to cause varus or valgus deformities. It should be pure translation. I then flex the elbow while keeping traction. This makes reduction more stable because the main pull vector of the triceps muscle becomes the fracture compressor (or even flexor) rather than the extensor. In words, the triceps muscle force changes from a deforming force into a stabilizing force. Successful completion of this step is marked by the fact that the child’s fingertips can touch the shoulder easily.

Fluoroscopic assessment to confirm reduction using AP and two oblique views at 90° (lateral and medial oblique views). A lateral view can be taken either by carefully rotating the elbow if the fracture is stable enough or by rotating the X-ray machine if not. After flexing the elbow, there will be overlapping of the proximal ulna and radius over the fracture site (Jone’s view) but it is still possible to assess the continuity of the medial and lateral columns and Baumann’s angle (see Figure 18.10).

Once the fracture is reduced, it needs to be held in the reduced position until stabilized. There are two methods that I use depending on the fracture stability and the experience of my assistant (Figure 18.11). If the fracture is stable and I do not have an experienced assistant, I would tape the limb (hand to shoulder as in Figure 18.11) to keep it reduced; otherwise, I will rely on my assistant to hold it reduced during the procedure. In this child, I cannot use the taping method as there is a wrist fracture.

Then I prepare the skin using antiseptic solution and drape the upper limb. I use two smooth K-wires (size 2 mm unless the child is very small, when I use a smaller size). I pass the first wire through the capitellum in a superomedial direction through the olecranon fossa and the medial cortex (holding up to six cortices – this is not always possible depending on the site and direction of the fracture). I pass the second wire through the distal fragment with maximal spread at the fracture site from the first wire. The wires should not be crossed inside the bone (or even worse, at the fracture site). I check the wires on the AP and lateral views to ensure optimum positioning. Then I test the fracture stability; if it is stable, I will do the wrist, but if not, I may supplement with a third wire or I may use the medial wire. The latter requires a small incision to visualize the ulnar nerve.

EXAMINER: This is what has been done. Any thoughts?

CANDIDATE: The images showed a good reduction of the humeral fracture. There may be a slight lateral translation on the AP view. This needs careful follow-up. The positions of the wires are perfect. The medial wire is passing through the capitellum, olecranon fossa and as low as possible through the medial cortex. This gives good purchase to the bones as it passes through six cortices. The lateral wire is going through the lateral column and is not crossing with the medial wire. On the lateral they are both in good position. The same can be said about the wrist.

EXAMINER: Was the second wire in the wrist necessary?

CANDIDATE: I think so, although it is not always possible to correctly judge the stability of a fracture from a static 2D picture. Moreover, the risk of compartment syndrome is high in this patient, and it is important to obtain a stable fixation in anticipation of cast splinting or even removal if compartment syndrome happens or if the vascular surgeon decides to explore and repair a blood vessel in this case. So, I think the surgeon was right to use two wires in the wrist.

EXAMINER: Fair enough. You stabilized the fracture but the radial pulse did not return. What would you do?

CANDIDATE: BOAST guidelines suggest that a well-perfused limb does not require brachial artery exploration, whether or not the radial pulse is present. However, if the upper limb remains ischaemic (pale, cold, delayed capillary refill and pulseless limb) after fracture reduction, a surgeon competent to perform small vessel vascular repair should explore the brachial artery and that is why I informed them before taking the child to surgery [11].

EXAMINER: This young boy presented with the above toe deformity. What is your thought?

CANDIDATE: The pictures show a typical overlapping fifth toe. It is a congenital deformity of the fifth toe which overlaps the fourth. Children and parents seek advice for either cosmetic reasons or problems with footwear. The toe is usually adducted and externally rotated and the MTPJ is dorsiflexed. The nail is sometimes smaller than the contralateral normal toe. I usually advise non-operative treatment in the form of passive stretching, neighbour taping and shoe modifications. If this fails I would offer a modified Butler’s procedure if they cannot cope with the symptoms.

EXAMINER: How do you perform Butler’s procedure?

CANDIDATE: The essence of the surgery is to lengthen all the tight structures at the back and pull the toe into the correct place using the dermodesis principle.

I perform a double racket incision then release the extensor digitorum longus and release the dorsal capsule. Then I close the skin (Y in V at the plantar aspect and V in Y at the dorsal aspect) (see Figure 18.14).

EXAMINER: This is a clinical photograph of newly born foot (Figure 18.15). What can you see?

CANDIDATE: This photograph shows typical features of a clubfoot (congenital talipes equinovarus (CTEV)) deformity. This is often summarized as (CAVE) deformity: Cavus (high arched foot due to tight intrinsic foot muscles, FHL, FDL); Adductus of forefoot (tight tibialis posterior); Varus (tight tendoachillis, tibialis posterior, tibialis anterior); Equinus (tight tendoachillis).

It looks severe. There are two classifications in use to assess the severity: Pirani score and Dimeglio scoring system. The former is more popular in the UK.

EXAMINER: How does Pirani score club feet?

CANDIDATE: The Pirani score is simple and reproducible. It uses six clinical signs to quantify the severity of each hind foot and mid foot deformity. Each component is scored as 0 (normal), 0.5 (mildly abnormal) or 1 (severely abnormal) (Table 18.2).

The six clinical signs are divided equally between the hind foot and midfoot as follows: