Module two: trauma and orthopaedics

The orthopaedic module is designed to help you understand the principles of handling bone and soft tissues such as muscle, tendons and contaminated tissues. The exercises have been chosen to give you hands-on experience of handling these tissues. Participants will be expected to discuss patient care with the faculty before, during and after the procedure being simulated. After each exercise the clinical relevance will be discussed and the results compared. 

The first exercise is to debride a simulated contaminated wound. Attention should be paid to the injured vital structures and the extent of dead tissue removal. The importance of aftercare should be emphasised. 

The second exercise is a flexor tendon repair in a pig's trotter. This simulates the human arrangement of the finger flexors at approximately twice the size. The exercise will emphasise the importance of understanding the anatomy of the tendon and the relevance of this to the strength of the repair. 

There will be a discussion of fracture management and the fixation of fractures. Application of a complete cast and the safe removal of plaster will also be taught. The session is completed with a discussion on the pitfalls of plaster applications.

Handling traumatised tissue
Handling tendons
Principles of fracture fixation
Plastering technique

Handling traumatised tissues

The primary care of a contaminated wound is pivotal in its subsequent healing. It is frequently undertaken imperfectly. Secondary procedures, once inflammation and scarring have established, may result in chronic disability. Six components to traumatic wound management are to be considered:

• wound toilet and irrigation;
• inspection of the wound;
• deep palpation of the wound;
• excision of dead or contaminated tissue;
• establishment of adequate drainage; and
• dressing of the wound for later inspection.

Drainage and debridement

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Exercise

• You will be supplied with a leg of either lamb or a large turkey in which a simulated traumatic and contaminated wound is shown.
• Clean the wound with water. Normal irrigant and antiseptics are water-based rather than spirit-based when dealing with open tissues. Cleansing should be done by both irrigation and using a swab. It is conventional to paint the contaminated wound from the centre working outwards.
• Initial inspection permits removal of gross contaminants and foreign material. The wound will have simulated glass or pebbles imbedded within it. It is essential that all of these are removed. You will subsequently be told by your tutor how many pieces of simulated glass were in the wound.
• Following the initial inspection, a methodical detailed examination is required using forceps and retraction. Work methodically, for example clockwise, so that no component of the wound is left unexamined. Look out for and identify any structured anatomy including nerves, vessels and tendons. You may be asked to demonstrate these.
• Palpation will reveal tracts which might otherwise be overlooked. This should again be undertaken methodically and is a further opportunity to examine every aspect of the wound. Foreign material will be felt by fingertip. Where a large overhang is present, it is wise to extend the wound to permit adequate toilet.
• Excise all 'dead' tissue, cutting back to healthy muscle. There is an appropriate amount of excision to be undertaken, but too little is worse than too much. Open up all cavities.
• This type of wound must not be under tension. Any cavity or sump must be adequately drained and when this cannot be provided by a drain through the existing wound, it may justify the use of a dependent drain. A corrugated drain is provided to be inserted into the most dependent cavity, applying the principles of drain usage. Employing artery forceps, identify the depth of a deep tract in the wound and pass the forceps from the base to the skin or surface and the snout of the forceps are presented to the surface. A corrugated drain which has been profiled by scissors is drawn back into the wound to rest through the line of penetration of the forceps. The drain should be sutured by a loose stitch into the skin and a safety pin applied to prevent it dropping into the wound.
• Wash the wound once finally with antiseptic, and place a loose pack (swab) soaked in antiseptic, such as acriflavine, into the wound and its cavities. (For the exercise use water).
• It is permissible to use one loose suture in order to keep the pack in place but under no circumstances should any attempt be made to close this type of wound. It is vital to have minimal tension and this will be checked by your tutor. This type of wound will be re-inspected at 48-96 hours post surgery when further excision and possibly skin grafting may be appropriate.

Handling tendons

Tendon surgery, particularly in the flexor tendon sheath in the hand, demands high surgical expertise and is beyond the remit of surgeons at SHO level. Rehearsing the technique however is of considerable value in developing surgical competence. Crushing or other forms of surgical trauma will provoke fibrous tissue reaction and lead to tenodesis. Improper or inadequate tension of the sutures will leave voids and cause failure of the repair. This will be tested by distracting the repaired ends.

Tendon repair

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Exercise

• The pig's fore trotter includes a human-like arrangement of the superficialis and profundus tendons. Display a main profundus tendon and cut it transversely with scissors.
• Handle the tendon at all times with the tip of a hypodermic needle and not with forceps, which may cause crushing. If necessary, trim the tendon ends until they are square and neat (Figure 33). Preserve length as far as possible.

Figure 33

• Refer to the diagram for installing a Kessler suture (Figure 34). The tendon is usually bean shaped in cross-section. Using 4/0 Ethiflex, install the sutures in the proximal tendon end first starting at the cut end. The entry suture should pass through the middle of one half of the sectioned tendon and follow parallel with the collagen fibres to 1.5cm, or twice the diameter of the tendon, and then exit.

Figure 34

• The transverse component of the suture now passes a loop back just distal to the exit point and through the central half of the tendon. The reciprocal longitudinal suture pass is now made, exiting accurately in the middle of the second tendon half. Repeated misjudged needle placement is poor technique. Do not snug up the sutures at this stage, unless adequate length of suture material is available for the reciprocal insertion of the suture design into the distal end of the tendon.
• Repeat the procedure into the distal end, having checked carefully the orientation of the tendon so that it will match the proximal end when the suture is tightened. Having placed the sutures in a satisfactory position, reduce the tendon accurately using the hypodermic needles and transfix in the reduced position. Methodically tighten the suture using the same sequence as was employed in insertion which will then leave the tail and needle end of the suture to be tied and triple knotted so that the knot is buried within the cut tendon end (Figure 35).

Figure 35

• Remove the transfixing hypodermic needles and apply tension to the tendon to ensure that the suture is performing adequately. If separation occurs the suture must be repeated.
• Insert the running stitch using 4/0 Nylon (Figure 36). Insert the needle into the paratenon approximately 2mm away from the cut edge. Do not over-tighten. Each bite of the running suture should be at a separation of approximately 2mm. Rotate the tendon using the hypodermic needles until the complete running suture is in position. Tie off to the original starting suture at the end using a triple throw knot.

Figure 36

Principles of fracture fixation

View the 'fracture management' part one video

View the 'fracture management' part two video

A fracture may be undisplaced, displaced into a position which is acceptable for adequate functional restoration or displaced into an inadequate position. Displacement must take in to account:

• shortening;
• angulation; and
• rotation.

A simple transverse fracture in which a periosteal or soft tissue hinge is present will not reduce by simple traction if displaced (Figure 37). It is necessary to exaggerate the original deformity so that the tension is taken off the periosteal hinge and the fracture slid into its position. Three-point fixation is then adequate to keep it reduced (Figure 38).

Figure 37

Figure 38

A spiral fracture is caused by rotation so that traction alone may not achieve reduction (Figure 39). Understanding the mechanism of rotation and reversing is necessary.

Figure 39

Short oblique fractures are usually caused by indirect force to the bone and are reduced relatively easily by traction but cannot be adequately stabilised with external splintage (Figure 40).

Figure 40

Comminuted fractures involve more than two simple pieces and generally are unstable (Figure 41).

Figure 41

These principles will be demonstrated by your tutor using both x-rays and wooden models comprising fracture types with a leather simulated periosteal flap applied. Make sure that you handle the models and become familiar with the principles of reduction.

Plastering technique

Plaster bandage is widely used for the splintage of fractures and immobilisation of joints and limbs to protect them while healing is occurring. The technique of plaster usage is applicable to general surgery, plastic surgery and orthopaedic surgery. Modern plaster bandage comprises anhydrous calcium sulphate which, when mixed with water, causes an exothermic rehydration to the crystalline form known as gypsum. Planning a plaster is dependent upon a particular application. It may require immobilisation of the joints above and below a mid-shaft fracture and careful selection of a limb position. The bandage layers must provide adequate strength without being unnecessarily cumbersome. Incorrect immersion in water will leave the plaster unsatisfactory to work, with weak spots. The reaction is rapid. A well-planned technique is necessary to ensure the optimal position for curing and crystal formation. The plaster may be a simple slab, a full plaster, or full and split. A complete plaster exposes the patient to the potential hazard of venous tamponade leading to Volkmann's ischaemia.

Back-slab

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This procedure will be demonstrated but not actually performed during the course. The actual plastering exercise will be restricted to a full forearm plaster.

• When applying a back-slab there should be minimal ulna deviation and, assuming the treatment is for a Colles type extension injury, approximately 10 degrees of palmar flexion is appropriate.
• A stockinette is prepared with a hole to permit the thumb to pass through. It should extend distally up to the metacarpophalangeal joints and proximally up to the elbow.
• The appropriate width of undercast padding should be applied. This should be not more than 10cm and run from the metacarpal heads, covering 50% overlap. Avoid hunching, particularly around the thumb, which is more easily dealt with by making a hole in the padding. Having completed the application of padding, ensure that there are no lumps and a consistent thickness is obtained.
• Six layers of plaster bandage of 15cm or 20cm width should be used. The slab should be of appropriate length and cut to accommodate the thumb and retain thumb movement (Figure 42). It should pass obliquely across the metacarpal heads as in the diagram (Figure 43) and proximally extend to within 4.5cm of the antecubital fossa to permit bending of the elbow.

Figure  42

Figure 43

• Dip the plaster in cold or slightly warm water retaining the two ends in your hand. Remove it, squeeze it lightly and then place it on the forearm to match the pre-prepared cuts for thumb and metacarpal heads. Stretch it longitudinally and pass the volar component carefully and smoothly under the flexor tendon region at the wrist. Now retain the plaster on the forearm using a cotton or crepe bandage pre-dipped in water, making sure that the bandage is applied smoothly.

• Mould the plaster as in the diagram using the flat of the hands so that three-point fixation is achieved (Figure 44). The shape of the plaster around the wrist is crucial in retaining position and should match the arrangements of the bones which are oval and not round (Figure 45). Make sure that no movement occurs until adequate setting of the plaster has been confirmed. The plaster will not be fully dry from surplus water until 24 hours after application, at which point it will have achieved full strength.

Figure 44

Figure 45

Full plaster

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Exercise

• You will be required to apply a below elbow cast on your partner and to split the cast. Your partner will then have the opportunity to reciprocate on you.

• All the equipment must be gathered before you start.

• Apply the stockinette only if there is no likelihood of swelling. The stockinette can cause constriction and, when cut through, may crease, thereby causing pressure. Having decided to apply the stockinette it needs to be measured distally up to the metacarpophalangeal joints and proximally up to the elbow allowing a bit extra. Cut a hole for the thumb, roll and apply to the limb.

• It is important to position the limb before you apply the padding. Maintain the position throughout until the cast is completely set, as movement equals ridges in the cast. The position will vary according to the injury.

• Open the bandages and keep them away from the water until you are ready to use them. In this case two 10cm POP bandages are required, with a spare on the trolley.

• Prominent bony areas, such as the ulnar styloid, may require protection with felt (Figure 46). A single layer of 10cm undercast padding should be applied smoothly, making a hole for the thumb (Figure 47). As you break the padding, hold the wrist firmly so that the patient doesn't suffer discomfort or movement at the fracture site.

Figure 46

Figure 47

• Soak the bandage in lukewarm water (20-25°C) according to the manufacturer's instructions. Cold water retards and hot water quickens the setting process. Both extremes are uncomfortable for the patient. Hold the bandage at 45 degrees loosely in the palm of the hand with the first few centimetres unwound to make it easier to find the end. Count three full seconds, remove and squeeze very gently to take out the excess water.

• Bandaging commences at the elbow end of the cast rolling the bandage from within out (Figure 48). Roll the bandage on evenly and without tension, covering about one-third of the previous turn and allowing tucks to form to accommodate the contours of the limb. The bandage should be brought up through the grip, gathering it together very gently (Figure 49). It should not be pulled down through the grip as this pulls the metacarpal heads together. Three times through the grip in total should be adequate; two with one bandage and one with the other. The second bandage is applied quickly before the first bandage has set. Constant smoothing and moulding is necessary to make the cast whole and not a succession of layers. Moulding must be done with the palms of the hands. Do not use the fingers as this can cause dents in the cast. Make sure the cast is moulded well into the palm. This can be done with the thenar eminence. Maintain the position until the cast is completely set, otherwise ridges will form.

Figure 48

Figure 49

• The limb needs to be rested on a pillow, because the cast could easily be dented and this might cause a sore. Trim the edges of the cast to allow full movements of the joints not held. The completed cast should extend from 4cm below the antecubital fossa to the heads of the metacarpals (Figure 50) and show the palmar crease (Figure 51). If stockinette has been used it can be turned back over the edge and secured in place with strips of plaster of Paris afterwards. Be careful when you apply the strips of plaster that you don't go over the stockinette edge and thereby create a sharp ridge.

Figure  50

Figure 51

• It is very important to give full verbal and written instructions to a patient on the care of the plaster and the prevention of possible complications. Make sure the patient really understands when they should urgently return to hospital. (See example sheet below).

Splitting a cast

• To split a cast to relieve circulatory or nerve impairment, a single lengthways/longitudinal cut is required for a plaster of Paris cast. If the cast is a resin-based product, it may need to be bivalved (cut in two halves) to relieve pressure. The padding, stockinette and any dressings must be cut right through to the skin.

• Bearing in mind the underlying injury and, if possible, avoiding bony prominences, mark the cast (Figure 52). This task can be performed with either plaster shears or, providing the cast is dry, an electric oscillating cast cutter.

Figure 52

Using plaster shears

• The blade of the shears should pass between the plaster and the padding. Keep the blade parallel with the limb. If the blade is tilted either way the point or the heel will dig in or nip the patient (Figure 53).

Figure 53

• The hand nearest to the cast holds the blade parallel and remains still. To cut the cast push the shears together with the other hand.

Using the electric cast cutter

• The saw has an oscillating circular blade which rubs its way through the hard plaster. It is relatively safe to use if handled correctly. It must be used on dry, padded casts with the blade held at right angles to the cast and a straight cut made without dragging the saw along the cast.
• Cut with the saw using an in and out motion holding the blade at right angles to the cast.
• Beware, the saw blade can cut the skin or get hot enough to create a bum if:
  • You drag the blade along the cast, instead of the in and out motion.
  • The cast is bloodstained when the padding and gauze becomes hard and the saw cuts straight through.
  • There is the presence of swelling or oedema and the skin has become taut and therefore easy to cut with the saw.
  • There is prolonged use.
  • The cast material is thick.
  • The cast is very large.
  • The blade is blunt or damaged.
  • The padding is thin and the patient may feel the heat even in normal use.
  • The cast is unpadded, in which case special care is needed.
  • The cast is a resin-based material, where more energy is required to cut through the material and therefore heat is generated and may burn the patient.
• If the patient moves or complains, always believe the patient, stop, reassess and continue carefully.
• Use the cast spreaders to separate the cast and the bandage scissors to cut the padding and any dressing down to the skin.
• A strip of padding can be placed in the split and a crepe bandage applied around the cast.

Bivalving

• To remove a cast fully, it should be bivalved, that is cut in two halves. Mark the cutting lines down the medial and lateral sides avoiding bony prominences and proceed as before using either the shears or the saw.

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