Joints need to be in particular positions for particular purposes, so be sure to use the right one. These positions seldom coincide with one another, and at least one of them, the position of function is absolutely critical.
The position of function is the best position for a joint to be in if it is going to be fixed, or if its movement is going to be severely limited. It is also called the position for ankylosis. Any kind of ankylosis, stable or unstable, is a dreadful disability if a patient's joint becomes fixed in the wrong position, so make sure that, if it is going to ankylose, it does so in the most useful position for him. The position of function varies from joint to joint, and may depend on what he wants to do with it. You never know for sure when a joint is going to ankylose, so put it into the position of function when you first see a patient with septic arthritis. For example, splint his knee just short of full extension; splint his right (or dominant) elbow flexed. Make quite sure he is in this position before you discharge him! Don't leave this task to a physiotherapist in the hope that it will be achieved later!
The position of rest is the most comfortable position for a joint to lie in. Put it into this position if it has to be rested for any reason, but is in no danger of ankylosing.
The neutral position of a joint is that from which its movement is measured. It is for anatomical description only, and is shown in Fig. 69-1.
The position of safety is for the hand only, and is shown in Fig. 75-8. It is the position in which the collateral ligaments of the finger joints are stretched, and in which fingers which are temporarily not going to be moved are least likely to become stiff.
THE POSITION OF A JOINT IS ALL IMPORTANT!
METHODS AND POSITIONS FOR JOINTS THE SHOULDER ASPIRATING THE SHOULDER. There are two approaches:
Anteriorly, feel for the patient's coracoid process just below his clavicle in the space between his pectoralis major and his deltoid muscle. Push the needle into the joint slightly below and medial to the tip of his coracoid process. Slope it laterally 30[de] and push it backwards, until it enters the loose pouch under the lower part of his shoulder joint (A, and G, Fig. 7-15).
Posteriorly, sit him in a chair to face its back, ask him to touch his opposite shoulder with the arm that is to be aspirated, so as to adduct and internally rotate his shoulder. Feel for the head of his humerus. Keeping the needle horizontal, push it it 30[de] medially into the joint space, from a point just under the posteroinferior border of his acromnion as in H, Fig. 7-15.
Fig. 7-16 THIS ILLUSTRATION OF THE POSITIONS OF FUNCTION is one of the most important ones in these manuals. If a joint is going to ankylose, the position in which it does so is critical. Notice that this patient's shoulder is abducted, his right elbow is flexed and in mid-pronation, his left elbow is extended (for toilet purposes), his knee is just short of full extension, and his ankle is in neutral and slightly everted. The girl in box B had an infected burn of her right elbow. The joint became infected. Tragically, it was allowed to ankylose in nearly full extension, so that she cannot eat with it or write! Kindly contributed by John Stewart.
EXPLORING THE SHOULDER. Approach his shoulder joint as if you were operating on his upper humerus for osteomyelitis as in Fig. 7-7, and separate his deltoid from his pectoralis major in his deltopectoral groove. Keep the wound open with a drain into the joint.
POSITION OF REST FOR THE SHOULDER. Put his arm in a sling.
POSITION OF FUNCTION FOR THE SHOULDER. If there is gross bone destruction, or you expect that he will have a stiff shoulder, put his shoulder into a spica in 45[de] of abduction, with his elbow just anterior to the coronal plane, in 70[de] of medial rotation so that he can get his hand to his mouth.
ELBOW ASPIRATING THE ELBOW. See also Fig. 72-4. Bend his elbow to 90[de]. Feel for the head of his radius. Using this as guide, push the needle into the posterolateral aspect of the joint, between the head of his radius and his humerus.
EXPLORING THE ELBOW. Make a 3 cm longitudinal incision posteriorly in the sulcus between his olecranon and the head of his radius. Go through the skin and fascia, insert a haemostat, and open it. Keep the joint open with a drain.
CAUTION ! Stay close to his olecranon, and remember that his posterior interosseous nerve winds round the neck of his radius 2 fingers' breadth distal to its head.
POSITION OF REST FOR THE ELBOW. Keep his arm in a sling in 90[de] of flexion.
POSITIONS OF FUNCTION FOR THE ELBOW depend on whether one, or both of them, are going to ankylose.
If his major elbow is going to ankylose, consider his needs. For example, Muslims and many other African peoples write and eat with their right hands and use their left hands for toilet purposes. If so, his right elbow should be more flexed than his left.
His major elbow will probably be most useful to him if it is flexed 10[de] beyond a right angle, with his forearm pronated 45[de] so that he can feed himself, scratch his nose, and write. Put it into this position by fitting him with a collar and cuff (72-9).
If both his elbows are going to ankylose, arrange their positions so that his major arm can reach his mouth. Let his minor one fuse in 10[de] short of full extension, so it can reach his anus.
THE WRIST ASPIRATING THE WRIST. Feel for his radial styloid; it will show you the line of his joint. Feel for the tendons of extensor pollicis longus on the ulnar side of his ''anatomical snuffbox' (74.4). Aspirate on its ulnar aspect, at the level of his wrist joint. Push the needle between extensor pollicis longus and the index tendon of extensor digitorum into the joint inclining it proximally 45[de] (B, Fig. 7-15).
EXPLORING THE WRIST. Flex and extend his wrist, as you feel for the exact line of the joint. Feel for the hollow between the tendons of extensor pollicis longus and the index tendon of extensor digitorum. Make a 3 cm transverse incision, taking care not to cut the cutaneous branch of his radial nerve which runs in the web space of his thumb.
Retract the skin edges and expose the joint through a longitudinal incision between the two tendons.
POSITIONS OF REST AND FUNCTION FOR THE WRIST. Keep it in 30[de] of extension with a volar plaster slab.
THE HAND THE POSITION OF SAFETY (James position) is peculiar to the hand and is the position which will minimize stiffness after an injury (75.2). Keep his MP joints nearly fully flexed, his PIP joints in 15[de] of flexion, and his DIP joints in 5[de] of flexion (Fig. 75-8 and many surgeons keep both IP joints fully extended). Keep his thumb well forward of his palm in opposition to his fingers, with its pulp about 4 cm from them. To maintain this position use aluminium finger splints, plaster slabs, or a boxing glove dressing (75.1), as appropriate. See also Sectiom 75.3.
THE HIP See also Section 7.18.
ASPIRATING THE HIP is difficult. The anterior approach is easier than the anterolateral one. His hip lies immediately behind his mid inguinal point. Use a thick lumbar puncture needle. If the anterior approach fails, try the posterior one.
For the anterior approach, feel for his femoral artery 2.5 cm below his inguinal ligament midway between his anterior iliac spine and his pubic tubercle. Insert the needle 1.5 cm lateral to the artery (and thus lateral to the femoral nerve). Push the needle in, inclining it 15[de] medially and 15[de] superiorly. This will aim it at the joint directly behind his mid inguinal point. Push it through the capsule into the joint. Aspirate. If you don't find pus, advance it into the cartilage. To prove that the needle is in the cartilage, rotate his thigh internally a little. This should move the adaptor of the needle medially. Withdraw it slightly to remove it from the cartilage, and aspirate. If necessary, alter its position and try again, if need be several times. If you cannot feel his femoral artery, insert the needle 2.5 cm below and 2.5 cm lateral to his mid inguinal point.
For the posterior approach lay him prone. Feel for his posterior inferior iliac spine and the centre of his greater trochanter. Insert your needle midway between these two points into his hip joint.
EXPLORING THE HIP. See Section 7.18.
POSITION OF REST FOR THE HIP. If you are sure that his painful hip is only temporary, rest it in moderate flexion and 15[de] of abduction. In this position his legs are comfortably spread apart. Hold his hip in this position with skin traction. To produce abduction, bring the cord holding the weight to the end of the bar at the foot of his bed. If necessary, make sure it stays there by moulding a plaster pulley on the bar. Or, have a detachable bar with notches at suitable places, which you can tie to the foot of his bed. Or, put both his legs into abduction.
POSITION OF FUNCTION FOR THE HIP. The minimum amount of flexion, and preferably none; 5[de] of abduction, and no rotation.
If possible, don't make the decision to aim for fusion yourself[md]refer him. If you cannot refer him, and decide to aim for fusion, don't apply a spica with his hip in the position of function, especially if he is a child. If you do, you will find, when you remove it, that spasm has rotated his pelvis anteriorly, and there is too much flexion. Instead, immobilize his hip in a spica in complete extension and 15[de] of abduction. When you remove the spica, you will find that it has gone into 15[de] of flexion, which is where you want it to be.
THE KNEE See also Section 79.3.
ASPIRATING THE KNEE. Extend the patient's knee. Push the needle into his suprapatellar pouch 2.5 cm above the upper border of his patella, from either the medial or the lateral side.
EXPLORING THE KNEE. With his knee extended, make a 5 cm incision one finger's breadth behind the medial edge of his patella and its tendon. Go through his quadriceps expansion, longitudinally, and put a curved haemostat into his suprapatellar pouch, under the surface of his patella. Put your finger into the joint and use it to remove the pus. Leave the wound open, or sew up the upper part, and leave a corrugated drain in place. Dress his wound and apply skin traction, or a plaster backslab. Without one or other he is likely to have a painful flexion contracture. Leave the drain in for 4 to 7 days.
BIOPSY OF THE KNEE. Make a 5 cm incision a finger's breadth behind the medial margin of his patella. Cut through his quadriceps expansion, and take a piece of diseased joint capsule for biopsy.
POSITION OF REST FOR THE KNEE. Apply skin traction to his lower leg to prevent flexion. Or apply a plaster backslab held on with a crepe bandage.
If he already has a flexion contracture following septic arthritis, put his knee in extension traction until it has been corrected. Then apply a cylindrical cast and encourage him to bear weight. With luck he will develop a painless bony ankylosis. If this does not happen, refer him for a compression arthrodesis of his knee.
POSITION OF FUNCTION FOR THE KNEE. Make sure his knee ankyloses in 10[de] of flexion, so his foot can just clear the ground when he walks. Do the same when both knees are ankylosed.
THE ANKLE ASPIRATING THE ANKLE. Find the line of his joint by moving his ankle. Insert the needle into its anterior aspect just medial to his lateral malleolus. Push it backwards and slightly downwards, so that it enters the space in the angle between his tibia and his talus.
EXPLORING THE ANKLE. The following incision will expose both his ankle and his tarsal joints. Start the incision on the anterolateral aspect of his ankle, 5 cm above the joint, and continue it downwards 1 cm in front of his lateral malleolus to the base of his fourth metatarsal, lateral to the extensor tendons of his toes.
Divide his superior and inferior extensor retinaculum as far as is necessary, so as to expose the capsule of his ankle joint. Then divide this and open the joint.
POSITION OF REST FOR THE ANKLE. Keep his ankle in neutral, without any flexion, extension, inversion, or eversion. Apply a plaster gutter splint.
POSITION OF FUNCTION FOR THE ANKLE. Keep it neutral and slightly everted. Inversion will produce painful callus under the head of his fifth metatarsal when he walks.
ANKYLOSIS IN THE WRONG POSITION IS A REAL DISASTER! Fig. 7-17 SIGNS IN SEPTIC ARTHRITIS OF THE HIP. A, Lie the patient flat, place your hand on his thighs and try to roll his leg to and fro. A normal hip rolls easily; if it is infected, this will be acutely painful. B, if you flex a normal hip, it will flex without rotation. If it rotates externally into position ''X' as you flex it, his upper femoral epiphysis may have slipped. This can happen spontaneously in teenagers (77.10); it also happens in late septic arthritis. Kindly contributed by John Stewart.