79. Knee
From Primary Surgery
79.1 The general method for the knee
The mildest knee injury is a bruise accompanied by an effusion. More severe ones can tear its menisci, or its collateral or cruciate ligaments, or break its bones. As with the ankle, ligamentous injuries are often missed and cause prolonged disability. Occasionally, a patient's patella 'or his knee dislocates. An injury which would tear the ligaments of an adult can displace the epiphyses of a child, who can also displace his tibial spine, or his tibial tuberosity. A severe injury makes the knee swell so much that you cannot tell where the fractures are until you have taken an x-ray. Fortunately, there are adequate closed methods for most knee fractures, and for most soft tissue injuries. Don't try to operate inside the knee. This chapter describes soft tissue injuries and fractures of the patella and lower femur. The next one describes fractures of the upper tibia which involve the knee. Most surgeons evolve their own examination routine for particular circumstances or parts of the body. As an example, here is one such routine for the knee, followed by the special methods for particular structures.
GENERAL METHOD FOR AN INJURED KNEE
HISTORY
This is vital. If the patient received a blow to his knee, his history is straightforward. If, however, nothing touched it, but i nstead, his foot locked on the ground and his knee twisted i nwards in flexion, and is now acutely painful, ask him these questions:
How soon did your knee swell? I f it swelled immediately, it is probably full of blood as the result of the rupture of a larger vessel. If it swelled more slowly over 6 or 8 hours, a smaller vessel has ruptured, or he has a sympathetic effusion.
If he was engaged in some violent activity, such as playing football, could he continue the game? If he could continue, he probably has only a minor injury.
If: (1) he felt a snap or a pop, or (2) he has had previous episodes, or (3) he has locking and pain on weight bearing, he has probably injured a meniscus. Where is the pain?
A ROUTINE EXAMINATION FOR AN INJURED KNEE
Sit the patient on the couch with his knees over the edge of it, and his trousers and his shoes off. Look at and feel the muscles of his thighs. Look for atrophy, and compare the two sides. If necessary, compare their circumferences with a tape measure.
Extend his leg, place it on your knee, and examine it for fluid as in Section 79.3.
With his knee extended, grasp his ankle between your arm and your chest, on your right side for his right knee, and on your left side for his left knee.
Now, with his knee flexed a degree or two, to unlock his cruciate ligaments, put both your hands just below his knee and try to move it from side to side. This will test the integrity of its collateral ligaments. There is very little movement in a normal knee.
With his knee flexed, use both your thumbs to palpate his medial and lateral joint lines. Feel for tenderness anteriorly (anterior meniscus injury), in the mid-joint line (ligament or meniscus injury), and posteriorly (posterior meniscus injury, or lesions of his hamstring tendons).
Feel for the origins and insertions of the medial and lateral collateral ligaments above and below the joint lines.
Now lie him flat on the couch. Flex and extend his knee fully. His injured knee should extend and flex as much as his normal knee, and touch or nearly touch his buttocks.
Flex his thigh and his knee. Grasp his ankle and rotate it internally and externally. Finally, lie him on his face, with his knee extended, and feel the back of his popliteal fossa.
CAUTION ! (1) If a child has spontaneous knee pain, examine his hip. His upper femoral epiphysis may have slipped (77.10). (2) In any severe knee injury, always examine a patient's hip.
SPECIAL METHODS FOR AN INJURED KNEE
Apply the appropriate special tests for the following lesions: effusions (79.3), injuries of the patient's collateral ligaments (79.5), tears of his cruciate ligaments (79.6), injuries of his menisci (79.7), and injuries of his quadriceps mechanism (79.11).
X-RAYS Take an AP and a lateral view of his knee.
NERVES AND PULSES Have you remembered to examine his
common peroneal nerve (55.8), and his dorsalis pedis and
posterior tibial pulses? This is especially important if his tibial
condyles have been fractured.
DIFFICULTIES WITH AN INJURED KNEE
If a patient has VARUS OR VALGUS INSTABILITY with his knee fully extended, he has probably torn his collateral ligaments, the posterior capsule of his knee, or perhaps his posterior cruciate ligament.
79.2 A plaster cylinder for the knee
This is the standard treatment for a soft tissue injury, and for some fractures. It will protect a patient's injured knee until the pain and swelling have gone, and it may allow him to walk.
If you are not careful, it will slip down his leg and press on his Achilles tendon, or on the dorsum of his foot. You can prevent this happening by compressing the cast from side to side above the flare of his femoral condyles, and by holding it in place with pieces of strapping.
A plaster cylinder is usually applied with a patient's knee just short of full extension, or occasionally in 30 ° or 60° of flexion. If you apply it in full extension, it will be very painful indeed. Even if you have applied it correctly, his knee is sure to be stiff and extension will be limited when you remove it, so warn him about this, and show him how to do extension exercises. Cycling is excellent exercise for a stiff knee.
A PLASTER CYLINDER TO IMMOBILIZE THE KNEE
INDICATIONS (1) Soft tissue injuries of the knee. (2) Postoperative immobilization. (3) Some fractures.
METHOD Stick a piece of adhesive strapping down the
medial and lateral sides of the patient's lower leg, as for a
plaster gaiter (81.6). Let them hang loose below his malleoli.
Apply a cast from his groin to about 3 cm above his malleoli with his knee in 10° offlexion. While the cast sets, compress i t between the palms and heels of your hands from side to side (not from front to back) just above the flare of his femoral condyles, as in Fig. 79-1.
Pull the strips of strapping tight up over the cast and bind them into it with a few more turns of plaster bandage. Start quadriceps exercises as soon as the cast is dry.
CAUTION ! Never apply a plaster cylinder in full extension-his knee will be very painful and osteoarthritis may follow later.
79.3 Fluid in the knee
If a fracture enters a patient's knee, it rapidly fills with blood which remains liquid for about 2 weeks. Aspirating his tensely swollen knee will greatly relieve his pain and make moving it much easier. Aspiration is also useful in diagnosing less obvious effusions, and especially in distinguishing between infection (7.18) and haemorrhage. Careless aspiration can infect a sterile effusion, so take the strictest aseptic precautions.
| ASPIRATE ALL KNEE EFFUSIONS |
FLUID IN THE KNEE
TESTING FOR AN EFFUSION The first sign of an effusion i s the obliteration of the natural hollow on either side of a patient's patella. Press the fluid from one of these hollows i nto other parts of his knee, and then, in a good light, slowly watch the empty hollow refill.
Can you ballot the patient's patella? Grasp his thigh between your fingers and thumb just above his knee. Press the effusion distally towards his patella, so as to drive fluid from his suprapatellar pouch down into his knee. Press his patella sharply. If fluid is present, you can feel his patella tapping on his femur. This sign is absent if there is very little fluid present, or so much that his patella cannot reach his femur. Compare his injured knee with his normal one.
If his knee is hugely distended and fixed in flexion, aspirate it. When you have done so, examine it again.
ASPIRATING THE KNEE
EQUIPMENT A sterile 20 ml syringe, a large (1.2 mm) needle, iodine, swabs, adhesive strapping, and a receiver.
CAUTION ! Make quite sure that the equipment has been properly sterilized. Never aspirate a knee in a minor theatre used for septic cases. This is a procedure for the main theatre, or a clean treatment room with full aseptic precautions.
ASPIRATION Introduce the needle into the patient's
infrapatellar pouch from the medial side laterally. Aspirate
the effusion.
If the effusion is bloody, let it settle for 5 minutes and then look at its surface. If fat from an injured marrow cavity is floating on the top, a fracture has entered his knee.
THE FLUID Examine this carefully.
Blood with fat floating on the top-a fracture. Blood or blood stained fluid-synovial or capsular tears. Clear amber fluid-torn menisci, osteoarthritis, loosebodies, or synovitis. Cloudy fluid-septic arthritis, or rheumatoid arthritis. If there are 'rice bodies' he probably has a tuberculous arthritis. If it is frank pus, he probably has septic arthritis. If possible, send the fluid for culture.
79.4 A swollen knee after a minor injury
When a knee swells after a minor injury the cause can be: (1) a minor fracture, (2) a synovial or capsular tear, (3) a loose body, (4) a torn cartilage, or (5) synovitis of obscure origin. Take a careful history. If the patient has had previous episodes, he may have a chronic ligamentous injury, a loose body, or a torn cartilage. A history of locking suggests a loose body, or a torn cartilage. An abduction or adduction injury suggests a torn ligament, and a rotational one suggests a torn cartilage. The absence of any history of force suggests a loose body or 'synovitis' This has many causes, including rheumatoid arthritis, gonococcal disease, etc. If the swelling appeared slowly over 6 to 12 hours before producing acute pain, it is probably a haemarthrosis, perhaps from quite a minor injury. Examine his knee (79.1), aspirate it (79.3), and look at the fluid. Remember that repeated haemarthroses may be the first indication of a bleeding disorder.
TREATMENT FOR A MINOR KNEE INJURY
Minor fractures, and synovial and capsular tears. Aspirate the patient's knee as necessary. Apply a well padded dressing, and mobilize it as pain subsides.
Loose bodies Refer him, removing a loose body from the knee is a specialist task.
Synovitis Rheumatoid arthritis is responsible for half the cases. Treat the underlying cause and make sure you exclude TB.
79.5 Tears and sprains of the collateral ligaments
A patient can injure his knee while it is extended, or flexed (as when his knee hits the dashboard), and sustain a variety of complex injuries to his collateral ligaments, his cruciate ligaments, and his menisci. Sprains (partial tears) of his collateral ligaments are usually obvious, but you can miss a complete tear because: (1) It causes less pain than a sprain, so that he may even be able to walk, and you may be able to move his knee. (2) Blood can escape through the capsule in a complete tear, so that swelling is less. Distinguishing between a sprain and a complete tear is important, because a complete tear needs primary repair whereas a sprain will heal with closed treatment. Both sprains and tears make a collateral ligament painful and tender, thus the only sure way to distinguish between them is to examine the patient under general anaesthesia. A sprain is only a minor injury, but a tear can cause prolonged disability.
COLLATERAL LIGAMENT INJURIES OF THE KNEE
EXAMINATION Tenderness is a good indication as to where a patient's ligament has been injured, so feel for it carefully. His collateral ligaments may be tender over their femoral or tibial origins. Narrowly localized tenderness (usually about 2 cm above the joint line) indicates a partial tear. Severe diffuse tenderness suggests a complete one.
If his medial ligament is tender at the joint line, his medial meniscus may be injured also.
If you suspect that a collateral ligament may have been ruptured, test the stability of his knee like this.
Hold his leg with one of your hands just above his injured knee, and the other one just above his ankle. With his knee just short of full extension move his lower leg from side to side. If either of his collateral ligaments is grossly torn, his tibia will wobble on his femur.
CAUTION ! (1) His knee must be just a little flexed when you do this test. If it is fully extended, his cruciate ligaments will stabilize it and mask tears in his collateral ligaments. (2) A fracture of his tibial plateau can also make his knee unstable and resemble a torn collateral ligament.
Alternatively, sit him on a table. Sit on a chair in front of him. Hold his foot and ankle firmly in your axilla. With both hands, grasp his upper tibia with his knee flexed 5°. Try to angle his leg on his knee.
X-RAYS If you suspect torn medial collateral ligaments, sedate
the patient, put a pillow between his ankles, bind his knees
together, and take an AP view to compare the joint space between
his femoral and tibial condyles on either side, as in Fig.
79-3. Or, using a lead glove, stress his injured knee as the Xray
is taken.
EXAMINATION UNDER ANAESTHESIA If you want to
distinguish between a sprain and a tear, examine him under
anaesthesia, in full extension and 15° of flexion. His cruciate
li gaments can make his leg appear to be stable, even when
his collateral ligaments have been torn. With a few degrees
of flexion his cruciates are relaxed and the tears of his collateral ligaments will become more obvious.
THE TREATMENT OF TEARS OF THE MEDIAL AND LATERAL COLLATERAL LIGAMENTS
If there is no medial or lateral angulation when you examine a patient under anaesthesia, his injured collateral ligament is probably only sprained and not torn. So fit a plaster cylinder (79.2) to relieve pain and protect his sprained ligament. If he is walking easily without pain at 2 weeks, remove it, otherwise leave it on for 2 more weeks, then start active knee exercises.
If lateral angulation causes an opening of less than 1 cm on the side of the knee joint, proceed as above, but apply the cylinder in 30° of flexion (to relax his torn ligament) and continue immobilization for 6 to 8 weeks. Warn him that extension will be slow to return, and tell him to do progressively increasing extension exercises. This may give as good results as attempts at secondary repair.
If lateral angulation causes an opening of more than 1 cm on one side of the knee joint, the collateral ligament on that side Is torn, and perhaps the patient's meniscus is injured also. Refer him immediately for primary repair. This gives only fair results in most cases. If you cannot refer him, fit a plaster cylinder as described below.
If you see a patient after the first week, primary repair Is more difficult and less satisfactory. So fit a plaster cylinder with his knee just short of full extension in the position of abduction or adduction that will best close up the torn ligament. Leave it on for 6 weeks.
If he presents late with an unstable knee, refer him for secondary repair, this has about a 50% chance of a good result.
79.6 Torn cruciate ligaments
A patient's posterior cruciate ligament is attached posteriorly on the proximal surface of his tibia, and anteriorly on his femur. It tightens when his tibia is pushed backwards on his femur. He can tear it when his tibia hits the dashboard of his car and is driven back on his femur. Less often his anterior cruciate is injured if his foot remains on the ground, and his femur is driven backwards by some twisting injury. Satisfactory repairs are seldom possible on either of these ligaments.
INJURIES TO THE CRUCIATE LIGAMENTS
EXAMINATION If the patient's knee injury is very recent, and the following test is likely to be painful, examine him under anaesthesia. Otherwise, ask him to sit up, bend his knee to 90°, and put his foot on the couch. Sit on his foot, then take hold of the proximal end of his tibia with both hands, and move it forcibly backwards and forwards. There should be very little movement.
Now with his normal knee in the same position, look at the outline of both his knees from the side. Observe especially the relative positions of his tibial tuberosities and his patellae, as in A, Fig. 79-4. Compare his normal with his injured knee.
If you can move his tibia forwards, his anterior cruciate is probably torn. This is rare.
If you can push his tibia backwards, his posterior cruciate is probably torn.
THE TREATMENT OF INJURED CRUCIATE LIGAMENTS
If the patient's anterior cruciate ligament is torn, rest him in bed until most of the pain has gone in about 5 days. Then start active quadriceps exercises. Hypertrophy of his quadriceps can compensate for a tear of his anterior cruciate with complete return of function. Some surgeons advise an operative repair.
If his posterior cruciate is torn, immobilize his knee in 60° of flexion for 6 weeks. Injuries of this ligament are not worth referring.
79.7 Torn menisci
A footballer playing on hard ground can easily injure his menisci. The pressure of his femoral condyle against his tibia may split one of them, so that a piece becomes loose at one end and may lock his knee. A history of injury to a flexed loaded knee is highly suggestive, especially if he also says that it sometimes locks. When you see him, his quadriceps will already have started to waste, he may have an effusion, and he will be tender over the joint line of his knee. Most patients learn how to move their knees so as to unlock them. If a patient has repeated episodes of locking with effusion, refer him for menisectomy. This suggests the presence of a large tear which will eventually cause osteoarthritis.
INJURIES TO THE MENISCI
EXAMINATION Tests for injuries to a patient's menisci are not reliable, so place great importance on the history of the injury (flexion of a loaded knee) and a history of locking.
(1) Sit him down and extend his knee. With the tip of your fingers press firmly over the joint line just medial to his patellar tendon. Now, still pressing hard, flex his knee and at the same time rotate his tibia to and fro on his femur several times. You may feel the torn meniscus click and move under your finger, or roll against the head of his tibia, showing that it is displaced.
(2) Press with your thumb close beside his patellar tendon over the anterior horn of his medial meniscus. Flex and extend his knee passively. Do the same thing with the anterior horn of his lateral meniscus. Compare the tenderness with that of his normal leg. Significant tenderness in one place suggests that the meniscus under it is injured.
(3) Lie him on his face. Hold his foot, and flex his knee, until his heel almost reaches his buttock. Rotate his foot externally as far as it will go and then extend it. If you feel a 'click' while you do this, the posterior horn of his medial meniscus is probably torn.
TREATMENT Refer him early, because the result of late
menisectomy is likely to be bad.
If his knee is locked, and you cannot refer him, give him a general anaesthetic and manipulate his knee. Use combinations of flexion, extension, rotation, abduction, and adduction. You may be able to unlock it, temporarily at least.
79.8 Dislocation of the knee
A violent injury such as a road accident can dislocate a patient's knee. At the same time it may tear his cruciate ligaments, and one or both of his collateral ligaments. It may also obstruct his popliteal vessels, and impair the circulation to his lower leg. Reduction is usually easy, but the easier it is, the more likely his knee is to be unstable afterwards. If his knee is completely dislocated, it is unlikely to function normally again. An injury severe enough to dislocate his knee may also injure his hip, so check that too.
A DISLOCATED KNEE Check the circulation in the patient's l eg. Reduce his dislocation, and, if necessary, aspirate his knee. If he has a skin wound, toilet it. If possible, suture the torn ligaments back in place with catgut.
Apply a plaster cylinder with his knee flexed to 90°, and split it to allow for swelling. Leave it on for 3 to 4 weeks. Remove it and start gradual extension exercises. He will take several months to regain his normal movements.
Start quadriceps exercises from the begining. Let him start weight bearing in his cast as soon as he can lift his leg.
If reducing his dislocation does not restore the circulation to his leg, his popliteal artery is probably injured. You will not have time to refer him, so get what help you can and explore his popliteal space (3.7). If you cannot restore his circulation, he will probably lose his leg at his knee.
79.9 Dislocation of the patella
There are two varieties of this injury: (1) Some sudden uncoordinated movement of a patient's leg dislocates his patella outwards, and rotates it so that its articular surface lies against the outer side of his femur. The fibres of his vastus internus tear, and his knee fills with blood. He is in great pain, his knee is flexed and he cannot move it. His knee has an abnormal shape, and you can feel that his patella is not in its normal place. Provided you remember that dislocation is a possibility, the diagnosis should not be difficult. (2) Partial dislocation can follow a much less serious injury, and is more common in women.
A DISLOCATED PATELLA If you see the patient within a few
hours of the injury, you may be able to reduce his dislocation
without an anaesthetic. His knee will probably be flexed.
I f you extend it slowly, his patella will probably reduce spontaneously.
If it does not, ask your assistant to extend the
patient's knee. While he does so, place both your thumbs on
the outer side of the patient's patella and suddenly flick it
back into the midline while he is relaxed and unaware. If this
fails, anaesthetize or sedate him. As soon as his muscles
relax, glide his patella back into place.
If possible, take skyline X-ray views and look for displaced bony fragments free in his joint.
The medial attachment of his quadriceps to his patella may be torn, so fit him with a plaster cylinder (9.2) for 2 or 3 weeks, and encourage him to do straight leg raising and quadriceps exercises. Recurrence is rare. If his dislocation does recur, or if he gives a history of recurrence since childhood, refer him for reconstructive surgery.
79.10 Injuries of the quadriceps mechanism
If a patient falls on his leg at the same time as his quadriceps tendon is contracting, he can sustain any of the injuries shown in Fig. 79-5. He can rupture his extensor expansion (1), or he can pull it from the upper pole of his patella (2). He can also fracture his patella (3), as described in the next section. He can pull his patellar tendon away from his patella (4), he can rupture it (5), or he can pull it away from his tibia (6). But the result if always similar, he cannot extend his knee fully, he drags his leg as he walks, and he has difficulty climbing stairs, or going up a slope. Apart from fracture of the patella, all these other injuries are rare. Repairing them involves open joint surgery, with the risk of infection, so refer the patient if you can.
As with the olecranon (72.18), the proper management of these injuries, especially fractures of the patella, depends on whether a patient's quadriceps mechanism is intact or not. This is the mechanism which extends his knee.
TESTING THE QUADRICEPS MECHANISM Feel his patellar
tendon between the lower margin of his patella and his tibial
tuberosity and ask him to gently lift his leg off the couch. Pain
may prevent him from doing this, but if you can feel his
patellar tendon tightening, you can be sure his quadriceps
extension is sufficiently intact to justify closed treatment.
This test may be difficult.
Palpate his quadriceps tendon, his patella, his patellar tendon, and its insertion. Feel for a transverse crack in his patella with your thumb nail.
Put your hand on his patella and ask him to flex and extend his knee. If the surfaces of his patella and femur are rough, you may feel crepitations as they slide over one another.
79.11 Patellar fractures
Fractures of the patella resemble those of the olecranon, but are more often missed. A common mistake with disastrous results is to suture a cut knee which overlies a patellar fracture and an open knee injury. Such a patient needs a careful wound toilet and exploration of his knee under general anaesthesia.
A patient can fracture his patella in two ways: (1) He can receive a direct blow to his knee which fractures it directly; this usually causes a stellate fracture which leaves his quadriceps mechanism intact. In a fracture of this kind the fracture lines usually radiate out from a central point as in A, Fig. 79-6. (2) He can fall on his leg at the same time that his quadriceps are contracting. This typically happens in someone who is past middle age, who misses his step, who hears something snap in his knee, and who then falls to the ground. Afterwards, he has difficulty walking. The injury has split his patella horizontally into two halves, separated them, and torn his extensor expansion more accurately, his patellar retinaculae). This is the tough brous capsule of the knee on either side of the quadriceps tendon, the patella, and the patellar tendon. In both kinds of fracture a patient's knee swells with blood and he cannot extend it.
If a patient's quadriceps mechanism is intact, you can treat him by closed methods. If it is not intact, you will have to repair it by one of the methods in the next section. If this is not done, he will not be able to extend his knee the final 20°, although he will be able to walk.
CLOSED METHODS FOR PATELLAR FRACTURES
INDICATIONS (1) The patient's quadriceps expansion must be intact as tested for in Section 79.10.(2) The fragments must not be widely separated. Provided these conditions hold, conservative treatment is indicated, particularly if he has a stellate fracture with many radiating fracture lines.
TREATMENT There will be blood in his painful swollen knee,
so aspirate it.
If pain and swelling are mild, teach him to use crutches (77.1). No dressing is needed.
If pain and swelling are severe, fit him with a plaster cylinder (79.2).
Alternatively, bandage his leg from his ankle to his groin with alternate layers of cotton wool and crepe bandage, making four layers in all. Keep him in bed until he has regained control of his knee. Then allow him up. Encourage him to move his knee actively within the limits of the bandage.
After 2 weeks, remove the bandages and add knee flexion exercises to those he is already doing.
79.12 Operations on the quadriceps mechanism
If a patient's quadriceps mechanism is not working, you will have to repair it.
If his patella is in two pieces all you need do is to sew up his extensor expansion on either side of it. The tear can be opposite the middle of his patella, in which case it will be in two halves, or it can be at the top or bottom of his patella, in which case there may be one large fragment and one small one.
If his patella is in several widely comminuted fragments, excise them and pass a purse string suture around the hole where his patella was.
Although operations on the patella itself are possible, they are not always necessary, because the important part of the extensor mechanism is not the patella, but the quadriceps expansion around it. Rarely, the patella may be intact and only the patellar tendon or quadriceps tendon may be torn, and need suture.
When the patella is in two pieces, they should be fixed so that the posterior surface of the patella is smooth. Our contributors differ as to how you should do this. Some advise that you wire the patella round its circumference, and others suggest that you pass Kirschner wires through it.
OPERATIONS ON THE QUADRICEPS MECHANISM
If possible, refer the patient. If you cannot do this, proceed as follows.
INDICATIONS A patellar fracture with rupture of the
quadriceps mechanism.
WHEN TO OPERATE ? If the skin over the patient's patella
is normal, operate as soon as is practical. If it is bruised,
operate immediately. If it is infected, wait for 7 to 10 days until
infection subsides and treat the infection in the meanwhile.
ANAESTHESIA Give the patient a general or a subarachnoid
anaesthetic (A 7.4). Apply a tourniquet (3.8).
INCISION Make a transverse skin incision passing across the
top of the patient's patella. Be sure that the incision goes far
enough around his knee to reach the ends of the tears. It may
need to go half way round on each side. If an area of skin is
bruised, avoid it, or excise it.
Reflect his skin proximally and distally to expose the whole anterior surface of his patella, his patellar tendon, and his quadriceps tendon.
Inspect his quadriceps tendon medially and laterally. Remove any small detached fragments of bone.
His knee will be full of blood; wash it out until all clots are gone. Use a 20 ml syringe to squirt saline under high pressure into all its recesses, until the fluid comes out clear. Alternatively, wash it out with a titre of intravenous saline.
SUTURING THE EXTENSOR EXPANSION
If the patient's patella is in two halves, and his extensor expansion is torn, sew it up from the sides towards the centre with strong monofilament sutures, or strong chromic catgut, as in A, and B, Fig. 79-7. Bring the fragments together accurately. If convenient, hold the two halves of his patella together with towel clips, while you sew up the expansion. You now have 5 alternatives, depending on your skill.
(1) You can leave the repair as it is.
(2) You can strengthen the repair by passing a figure of eight
loop of strong catgut through the patient's quadriceps expansion above, cross it over his patella, and pass it through the attachment of his patellar tendon. To maintain a smooth undersurface to his patella, do this with his knee flexed about 30°.
(3) You can encircle his patella with 1 mm stainless steel wire, thick chromic catgut, or monofilament, preferably with a large Gallie needle. Alternatively, thread the wire through a large intravenous needle as in Fig.54-7. Pass the wire in and out of his quadriceps expansion, taking big bites very close to his patella. Go all around the superior border and lateral borders and pass the wire straight through the patellar tendon, close to his patella. Finally, bring the ends together and twist them tight. This circumferential wiring prevents the fragments separating. Place this wire superficially in his patella, so that when his knee flexes, the posterior aspects of the fragments are brought together in compression. The wire must lie close to his patella, particularly above and below, or it will cut out when his knee flexes.
(4) You can combine method (3) with passing 2 Kirschner wires through the two halves of the patella from above downwards. Cut them short and bend over their tips.
(5) If you have the experience and the equipment, apply tension
band wiring as in Fig. 79-8.
EXCISING THE WHOLE PATELLA FOR COMMINUTED FRACTURES
If a patient's patella is in several widely separated fragments, use a very sharp scalpel to cut them out of the tendon. Keep the edge of the scalpel close to the bone all the time. Change the blade frequently as it blunts, and preserve the soft tissue coverings of the excised fragments.
Excise all fragments except for a small anterior chip in both proximal and distal tendons. Preserve as much tendon as you can. Repair the medial and lateral tears in his quadriceps expansion with interrupted sutures of thick catgut, beginning at the sides of his knee and working towards the gap created by removing his patella. Pass a purse string suture around the edges of this gap and pull them together. If one purse string does not seem to be enough, put in another one. Don't worry if you have a gap in the middle where his patella was.
If his quadriceps expansion is torn at the sides of his knee, be sure to repair it.
REPAIRING THE QUADRICEPS TENDON
This is open joint surgery, with the risk of infection, if your operating conditions are not good. Refer the patient if you can.
If you cannot refer him, join the ends of his quadriceps tendon with strong catgut.
If his quadriceps tendon has torn away from his patella
(rare), drill some holes for sutures through its edge as in C,
Fig. 79-5.
If his injury is an old one, and his quadriceps muscle has retracted, pass a Steinmann pin through his quadriceps tendon, apply traction, and when, after some days, the muscle has lengthened sufficiently, suture the tendon.
REPAIRING THE PATELLAR TENDON
This again is open joint surgery, so try to refer the patient. If you cannot refer him, suture the torn ends of his patellar tendon with strong catgut. If necessary, drill some holes through the lower pole of his patella to hold the sutures.
If the patient's patellar tendon has pulled away from his tibia, drill some holes in it to hold wire sutures, or hold his patellar tendon in place with a screw.
If his injury is an old one and his patella is much retracted, push his skin upwards and his patella downwards. Make two small nicks in his skin at either side of his patella tendon. Pass a Kirschner wire through it and exert traction for at least 2 weeks. Keep the wire in place and incorporate it (without its tensioner) in a long leg plaster cylinder (79.2). Then operate and repair the tendon.
POSTOPERATIVE CARE FOR OPERATIONS ON THE QUADRICEPS MECHANISM
Dress the patient's wound with gauze, cover this with plenty of cotton wool from 10 cm above his knee to 5 cm below it. Hold this firmly with two 15 cm crepe bandages. With his knee just short of full extension, apply medial and lateral plaster slabs from his groin to his ankle, pad them with cotton wool, and bandage them on firmly.
CAUTION ! These slabs must be strong enough to prevent him bending his knee as he awakes from the anaesthetic.
Encourage him to do regular quadriceps exercises and straight leg raising as soon as he can.
On about the twelfth day, remove his bandages and dressings. If his wound is clean and dry, take out the sutures. Protect his malleoli with padding and apply a plaster cylinder.
At 4 weeks bivalve his cast and let him start non-weight bearing extension exercises under supervision. Let him wear his bivalved cast for weight bearing. Abandon the cast: (1) when he can flex his knee to 90° and, (2) when he can extend it against resistance. This is usually at 6 to 8 weeks.
At 6 weeks start gentle active flexion exercises.
At 8 weeks, begin the passive flexion exercises shown in C, Fig. 79-7.
CAUTION ! He may refracture his patella and need a further operation if: (1) You let him walk too soon without his bivalved cast, and he accidentally stumbles. (2) He exceeds the exercise routine described above.
Gradually increase his exercises-provided he can fully extend his knee actively. If he ceases to be able to do this, don't allow him to flex his knee any further until he has regained active extension.
Expect the recovery of flexion to be slow. He will not be able to flex his knee fully for 4 to 6 months.
DIFFICULTIES WITH PATELLAR FRACTURES
If a patient's KNEE IS STIFF, continue progressive active movements. Don't try forcible manipulation under anaesthesia, or you may rupture the repair, tear his ligaments, or break the lower end of his femur.
79.13 Supracondylar fractures of the femur
The patient falls, strikes his knee, and breaks his femur above its condyles. Usually, there is little displacement, but it can be severe, as in A, Fig. 79-11. Occasionally, his gastrocnemius flexes the proximal end of the distal fragment, so that the shaft of his femur comes forward in front of it. When this happens, the distal fragment may press on his popliteal vessels and obstruct the circulation in his leg.
If the distal fragment is only mildly flexed, Perkins traction may be satisfactory. But if it is severely flexed, refer him for internal fixation, because this is a difficult fracture, even in the best hands, and permanent knee stiffness is common. If you cannot refer him, use traction in a Bohler-Braun frame, or Perkins traction with his knee hanging flexed for the first few days. Your hospital carpenter may be able to make a wooden Bohler-Braun frame as in Fig. 79-10.
SUPRACONDYLAR FRACTURES
If necessary, aspirate the patient's injured knee (79.3).
CHILDREN'S SUPRACONDYLAR FRACTURES
Anaesthetize the child, manipulate the fragments into position, and apply a long leg cast from his ischial tuberosity to his toes. Apply it with his knee in the position that best reduces the fracture. If necessary, flex it to 90°.
ADULT'S SUPRACONDYLAR FRACTURES
If you cannot refer the patient, proceed as follows.
MILD DISPLACEMENT If the fragments are in a reasonable
position and the patient's peripheral pulses are normal, apply
Perkins traction as in Section 78.4, but with his hip and knee
flexed, as in B, Fig. 77-11, or as in Fig. 79-9. Encourage him
to move his knee. Ignore lateral displacement on the x-ray,
and flexion of the distal fragment. Concentrate on getting
good antero-posterior alignment.
MORE SEVERE DISPLACEMENT Anaesthetize the patient, preferably using a relaxant (A 14.3). Insert a Steinmann or Denham pin through his upper tibia (70.11, 78.4).
If there is lateral displacement, apply the necessary side to side forces to reduce it. Then apply Perkins traction as below.
If there is overlap or severe angulation, ask one assistant to exert traction in the line of the patient's femur. This is movement 1 in Fig. 79-10. Ask another assistant to hold his iliac crests (2).
When your assistants have restored the length of the patient's femur, grasp its distal end with both hands, and bring i t forwards (3). Either apply Perkins traction with the patient's knee flexed, as in Fig. 79-9, or leave him on a Boehler-Braun frame for 10 days, until the bone ends have become sticky, before starting Perkins traction, as for a fracture of the femoral shaft (78.4).
If the above method of reduction falls, pass a Kirschner wire or a Steinmann pin through the anterior margin of the distal fragment. Pull it anteriorly and distally so as to reduce the fracture. The disadvantage with this method is that the pin or wire has to be inserted through the patient's joint capsule with the risk of infecting his knee. So remove it as soon as the fracture is stable, usually at about 3 weeks, and continue with traction through his tibial tubercle, with his knee at 90°.
CAUTION! As always in fractures of the lower limb, correct rotation (78-3).
Alternatively: (1) Apply a period of skin traction to his lower
leg first. (2) You may be able to get the lower fragment into
a suitable position by putting a pillow under his lower thigh.
If you still cannot achieve satisfactory reduction, refer him for open reduction.
LATER CARE FOR A SUPRACONDYLAR FRACTURE
Maintain traction until there is clinical union, usually in about 8 weeks. Two weeks later allow the patient up on crutches without weight bearing, as in Section 77.1; then after 2 more weeks, and if X-rays show solid union, start protected weight bearing. Don't allow unprotected weight bearing until his fracture has consolidated. His knee is likely to be stiff for a long time, and he will need continued exercises to help him extend it.
Alternatively, at 4 to 6 weeks apply a long leg cast while
he is standing, keep this on until the fracture has consolidated,
usually after 2 to 4 more weeks. This is a poor alternative
to continued Perkins traction, but it may be necessary
to free a bed.
79.14 T-shaped fractures of the femur into the knee joint
An adult falls on his bent knee and breaks his femur transversely near its lower end, as in B, Fig. 79-11. Another fracture line runs proximally from the joint to meet the transverse fracture line and separates his two femoral condyles. At the transverse fracture the fragments are usually end on, but they may be angled or displaced. His condyles may be separated by a gap, or one condyle may be displaced on another. Perkins traction usually reduces the displacement satisfactorily. If one of the fragments has turned through 180° open reduction is essential, so refer him.
79.15 Fracture of a femoral condyle
When a patient's knee is struck from the side and forced medially, the lateral condyle of his tibia usually fractures. Occasionally, the lateral condyle of his femur fractures instead, as in C, Fig. 79-11. If it is only slightly displaced, and not completely rotated, treat him in Perkins traction. But if the detached femoral condyle has completely rotated, and you cannot reduce it, immediate operative reduction and internal fixation are essential, so refer him.
79.16 Separation of the distal femoral epiphysis
A severe injury in an older child, which would cause a supracondylar fracture in an adult, produces a Salter Harris Type I epiphyseal injury (69.6a, Fig. 69-8) as in B and C, Fig. 79-12, or a Type II one as in A in this figure, or a Type IV injury. His distal epiphysis usually moves anteriorly, displacing the distal end of the shaft of his femur posteriorly where it may obstruct his popliteal vessels. His knee is swollen, he has a painful swelling immediately above it, and it may be unstable. Replace his epiphysis under anaesthesia, and hold his knee in flexion in a cast as described below. You can use Perkins traction if displacement is mild.
| TOPO (18 years) was injured in a football match, and severely displaced his
lower femoral epiphysis. No attempt at reduction was made, and a cast was applied. He was referred 6 weeks later by which time it was too late to try to attempt reduction. His severe angulation will have to be corrected later by osteotomy. LESSONS (1) Reduce epiphyseal injuries within 3 days. (2) Casts are not a universal treatment for all bony injuries. |
SEPARATED DISTAL FEMORAL EPIPHYSIS
DIAGNOSIS If you are not sure whether a child has ruptured his medial ligament, or displaced his epiphysis, take another fil m with his extended knee in a valgus position. This will show you the site of the abnormal movement.
MILD DISPLACEMENT Apply Perkins traction.
SEVERE DISPLACEMENT If possible, refer the child,
especially if his injury is of the rarer Salter Harris Type IV
variety (Fig. 69-8) in which the fracture line opens into his knee
joint. The method which follows assumes it is of the more
common Type I variety, with the distal fragment displaced
anteriorly. If the circulation in his leg is impaired, reduction
is urgent.
Anaesthetize him and lie him on his face, as in Fig. 79-13.
If the dIstal fragment is displaced sideways, apply traction (1) with his leg extended, and try to correct it (2).
Correct anterior displacement by applying traction to his partly flexed knee (3). Push the distal fragment posteriorly (4), and then increase the flexion of his knee to about 110° (5), just as you would if you were reducing a supracondylar fracture at the elbow (72.6).
If reduction is stable, apply an anterior plaster slab to his
flexed leg (C), and secure the slab to his thigh with circular
plaster bandages. Then put another plaster bandage around
his thigh and his lower leg (D). Don't flex his thigh more than
the degree of swelling will permit.
Ten days later reduce flexion to 60°. Remove the cast after a further 3 weeks. Movement will return slowly.
CAUTION ! (1) Monitor the circulation in his toes carefully during the early stages. (2) Don't prolong immobilization beyond 3 weeks, because the flexion contracture that results may be very difficult to treat. (3) Watch for loss of reduction, which may occur as late as the third week.
If reduction is unstable, refer him.
