Tibialis transfer for foot drop, from leprosy and other causes

A dropped foot, which a patient is constantly tripping over, is a great disability, but it is also a treatable one, whatever its cause: (1) If he has a strong tibialis posterior and gastrocnemius, and a mobile ankle, you may be able to transfer his tibialis posterior tendon. (2) If surgery is impractical, you can fit him with: (a) A toe-raising spring, as in Fig. 30-4, if necessary made with canvas or plastic straps, and using the rubber from an inner tube as the ''spring'. Or, (b) calipers, which will need careful fitting on an anaesthetic limb, if they are not to cause friction burns.

When leprosy has paralysed his lateral popliteal nerve, he cannot dorsiflex his ankle, so that as he walks he is liable to injure the lateral side of his foot, his toes, and the ball of his foot. Severe ulcers and marked deformity may follow. Transferring his tibialis posterior tendon to the dorsum of his foot will restore the dorsiflexion of his ankle, and reduce the risk of ulcers. Refer him if you can, but if you cannot, learn how to do the operation yourself under expert instruction. If this too is impossible, and you are a careful caring operator, follow the method below. It is the most complex method described here, and it right at the edge of ''Primary Surgery'. If leprosy is common in your district, it will be a procedure which is well worth learning, but only provided that there is someone who can prepare him for surgery, and re-educate him afterwards. Reconstructive surgery without physiotherapy is useless; but you can do the physiotherapy yourself, if you take enough time. Tibialis posterior and gastrocnemius are normally used together in walking. An important part of physiotherapy is getting him to separate these actions.

Detach his tibialis posterior from its insertion into his navicular, and divide its distal end into two slips. Thread these under the skin of the front of his leg and foot. Weave the medial slip into the distal end of his tibialis anterior tendon. Weave the lateral slip into: (1) the distal end of his peroneus tertius tendon (only 75% of people have one; it is really the fifth tendon of extensor digitorum longus, and is inserted into the medial part of the dorsal surface of the fifth metatarsal). This is the First Method, D, in Fig 30-11. Or, (2) if he lacks a peroneus tertius, and his peroneal muscles are weak enough to be sacrificed, weave the lateral slip into the distal end of his peroneus brevis tendon (E, the Second Method). Or, (3) if his peroneal muscles are not weak enough to sacrifice, or if the lateral slip of his tibialis posterior is too short to reach the lateral side of his foot, take a piece of tendon and use this as a free graft (not illustrated).

Make four incisions: Incision One, above and behind his medial malleolus, to let you free the muscle belly of his tibialis posterior. Incision Two, over his navicular, to free the insertion of its tendon. Incision Three, on the medial side of the dorsum of his foot, to let you weave the medial slip of his tibialis posterior tendon into the tendon of his tibialis anterior. Incision Four on the lateral side of the dorsum of his foot, to let you weave the lateral slip into his peroneus tertius or brevis. With the Second Method, you may have to make three more incisions, Five, Six, and Seven.

(1) Be sure to join his various tendons at just the correct length and tension, to get the right degree of dorsiflexion and eversion of his foot (this is the position in which the lateral side of his foot is higher than the medial side). His foot must be tightly dorsiflexed when you put it into plaster. To help you we tell you how to make a special foot-drop-positioning splint. This is critical. (2) If your tendon weave gives way, your work is wasted, so be sure to keep his foot dorsiflexed until it has united firmly. (3) Avoid subsequent toe drop by suturing his transferred tibialis posterior to the extensor tendons of his toes. (4) Don't be tempted to anchor his tibialis posterior to a hole drilled in his foot. This may work with other diseases, but in leprosy it will promote the disintegration of his tarsal bones.

Fig. 30-10 SOME CRITICAL DETAILS. A, measure the movement of his ankle like this (see also Fig. 69-1). B, a locally made goniometer. Hinge two boards together and nail a protractor, partly covered by a piece of card, to one edge. Mark the angles of dorsi- and plantarf lexion on it. C, exercises for tibialis posterior. D, a locally made foot-drop-positioning splint made in three parts, hinged together, and adjusted by chains. E, the frame for a leg rest (24[mu]24[mu]36 cm). F, how the leg rests on webbing, cloth, or bandage stretched across the frame. Kindly contributed by Grace Warren.

TIBIALIS POSTERIOR TRANSFER[md]''TPT' [s8]Grace Warren's method EXAMINATION. Check the power of: (1) The patient's tibialis posterior. Ask him to invert his foot against resistance (move it medially). The only other inverter is tibialis anterior, which is usually powerless or very weak in patients needing this transfer. (2) His peroneal muscles. Ask him to evert his foot, and feel his peroneal tendons contracting behind his lateral malleolus (if they are strong, you don't want to sacrifice them).

INDICATIONS. (1) Foot drop from any cause, provided he has a strong tibialis posterior and gastrocnemius (see below), and a mobile ankle. (2) If he has leprosy all these conditions must apply: (a) His leprosy must have been controlled, and he must have been free of reaction for at least 6 months. (b) His lateral popliteal nerve should have shown no sign of improving after 6 months of chemotherapy and the use of a toe-raising spring. (c) His tibialis posterior must be at least ''Power 4', and preferably ''4[+] or 5' (27.2). (d) He must have no ulcers or infections. (e) Preferably, he should be skin-smear negative. (f) His ankle must be suitably mobile, so test it like this:

Flex his knee to 90[de]. If you cannot passively dorsiflex his ankle beyond 0[de], tendon transfer alone is contraindicated.

Straighten his knee. If you can passively dorsiflex his ankle to 15[de] (unusual), a tendon transfer alone is enough. If you cannot do this (usual), you will have to combine tendon transfer with lengthening his Achilles tendon at the same time. Not lengthening his Achilles tendon is a common cause of failure.

If his ankle is too stiff to dorsiflex without inverting, he will not get a good gait. So refer him for a wedge osteotomy, perhaps with a tendon transfer later.

TENDON TRANSFERS FOR HIS TOES. If a foot is not being dorsiflexed normally, its toe flexors shorten. If you correct his foot drop, his toes will remain abnormally flexed, unless you do something to correct them. So his clawed toes also need tendon transfers (see 30.7), either at the same time that you transfer his tibialis posterior, or later. If you don't do this, he may walk with his toe-nails turned under his toes, which will ulcerate.

RECORD THE PROGRESS OF HIS FOOT. Do this as a baseline preoperatively. Do it again when he comes out of plaster, and at regular intervals afterwards. Record the angles of rest, active dorsiflexion, and active plantar flexion with his knee straight, and passive dorsiflexion with his knee at 90[de].

PREOPERATIVE PHYSIOTHERAPY is necessary to strengthen his tibialis posterior. Ask him to sit with his affected foot resting on his other knee and to invert it without using his Achilles tendon as in C, Fig. 30-10. Hang a weight (starting with 500 g and increasing to 4 kg, as the muscle strengthens) on the front of his foot, and ask him to lift this by inverting it. This exercise will help him to localize the action of the muscle that is to be transferred, so that it is easier for him to use afterwards.

ANAESTHESIA. (1) Subarachnoid anaesthesia (A 7.1). (2) Ketamine (A 8.1). (3) General anaesthesia (A 10.1). (4) Pethidine and diazepam (A 8.8); his foot will be partly anaesthetic anyway.

PERIOPERATIVE ANTIBIOTICS. An infected tendon transfer is a real disaster, so give him him chloramphenicol and metronidazole (2.9).

EQUIPMENT AND TECHNIQUE. Make a foot-drop-positioning splint, as in D, 30-10, from hardwood, hooks, hinges, screws, and two short chains. Boil or autoclave it. Ideally, you should use a 22 or 30 cm curved Anderssen tunneller, but you can use long Kocher's forceps. You will also need a leg rest, or cradle, to hold his leg about 20 cm above his bed after surgery. Ask your carpenter to make a tubular metal or wooden frame with webbing across it (E, 30-10).

For tendons use 2/0[nd]4/0 braided multifilament (nylon, prolene, polyglycolic acid [''Dexon'], ''Vicryl', or silk [less satisfactory]) or stainless steel (not catgut), on round- bodied, preferably trocar-pointed needles, or use Mayo cervix needles. For skin use nylon monofilament or steel.

For a tendon use several small stitches rather than one large one, and make sure that no single stitch bites more than half its thickness (which makes it liable to break later). Rough tendon ends are harmless on the dorsum of the foot, but if a tendon needs to glide, as when you weave peroneus brevis to tibialis posterior above the ankle, use fine (6/0) nylon monofilament to close over and bury the ends of both the tendon and the larger sutures, so as to prevent them sticking to surrounding structures.

CAUTION ! (1) Clamp a tendon as close to its cut end as you can, and excise the crushed area, which should be as short as possible. (2) Watch for and avoid the main vessels. There is no need to tie off all small ones.

PREPARATION. Lay him on his back, apply a tourniquet to his thigh (3.9), and sterilize his whole leg and foot below his knee. Clip a sterile towel round his thigh, so that you can lift his sterile leg without breaking sterility. A sandbag under the drapes will steady his leg, until you place it on the footboard.

INCISION ONE. Make a gently curved incision on the medial aspect of his leg, starting 2 cm above his calcaneus and 1 cm in front of his Achilles tendon, running parallel to the tendon for 5 cm, and then curving up to reach his tibia about 14 cm above his medial malleolus. Cut his fat and deep fascia, and find his Achilles tendon. Open its sheath, and lengthen it by one of the procedures in Fig. 27-11. Suture it so that his ankle will dorsiflex to 15[nd]25[de] with his knee straight.

Lift the tissues proximal to his medial malleolus, until you see the tendons, under his deep fascia. Slit this to find his tibialis posterior tendon which lies deeper than his flexor digitorum longus, F, 30-11, also D, Fig. 27-11. Make sure you have got the right tendon by pulling on it and seeing what it does[md]tibialis posterior inverts his foot, and does not flex his toes.

CAUTION ! Keep his exposed tendons moist by covering them with saline-soaked gauze.

INCISION TWO. Pull his tibialis posterior above his medial malleolus to find where it is inserted into his navicular. Make a 2[nd]3 cm incision along the plantar side of the tendon, from his navicular proximally. Incise into the tendon sheath and raise the tendon with a blunt hook or curved forceps.

CAUTION ! Make sure you have got the right tendon. It is the only one which is inserted into his navicular, and is usually thick and strong and the size of your little finger.

Clamp his tibialis posterior tendon with Kocher's forceps, as far distally as you can easily reach it, on the medial aspect of his foot, and cut it distal to this (don't follow or try to cut it where it inserts distally, among the arches of his foot). Pull it up into Incision Two, and free it from any adhesions, which would make it difficult to pull out of its sheath later. If there is a large sesamoid bone in it, remove this and reattach the Kocher's. Don't pull it out of its sheath yet.

INCISION THREE. Find his tibialis anterior on the dorsomedial aspect of his navicular. It is the most medial of the tendons on the front of his ankle. Twist his foot into dorsiflexion and abduction to see it more clearly.

Make a ''J'-shaped incision, with its long arm along the medial side of his tibialis anterior tendon, from the lower end of his tibia to his naviculo-cuneiform joint, and its short arm crossing the tendon laterally for 1 cm. Reflect the flap at the level of his deep fascia, and try not to cut his dorsalis pedis artery. Find his tibialis anterior tendon (check that you are not pulling on his extensor hallucis longus), and open its sheath.

INCISION FOUR is a quarter-circle curved incision, with its convexity towards his toes, extending from 2.5 cm lateral to the distal end of Incision Three, and passing across the dorsum of his foot, to reach the base of his fifth metatarsal, but not extending over the bone itself. Use big scissors and the ''push and spread technique' (4-8) to raise all his superficial tissues off the deep fascia over the dorsum of his foot, so that you can see his toe extensors, his peroneus brevis, and his peroneus tertius (if he has one) inserting into the shaft of his fifth metatarsal. Define and dissect out his peroneus tertius as far from its insertion as you can, above his extensor retinaculum. Cut its tendon free proximally, separate it from its muscle fibres, and leave it free, attached distally to its insertion.

Keeping above his extensor retinaculum, raise his skin and superficial fascia to join Incisions Three and Four, and make a skin bridge.

CAUTION ! His superficial fascia is thin here. Be careful not to cut his extensor retinaculum, which is his deep fascia at this point.

Use finger dissection, and blunt Kocher's, to tunnel up under his skin above his extensor retinaculum, keeping in the midline initially, and then turning medially towards the proximal end of Incision One.

Return to the proximal end of Incision One. Starting about 7 cm above his ankle, raise his skin from the deep structures. Complete the tunnel joining incisions One, Three, and Four. Tunnel under his skin and preserve his long saphenous vein. Make a pocket into which the muscle belly of his tibialis posterior will fit. If necessary, cut the deep fascia over the crest of his tibia, but avoid cutting his tibial periosteum (if you do it will promote adhesions later).

Above his medial malleolus put a finger under his tibialis posterior tendon, remove Kocher's forceps from its distal end in Incision Two, and pull the tendon up into Incision One (C, in Fig. 3O-11). Reclamp its distal end, and use the clamp to give you a good grip for traction, while your finger frees its muscle belly from the surrounding tissue at the back of his tibia.

CAUTION ! (1) Be careful to retract flexor digitorum longus posteriorly, so that tibialis posterior comes to lie anteriorly (F, 30-11 shows the anatomy of these tendons), between his flexor digitorum longus and his tibia (you don't want tibialis posterior to twist round digitorum longus). (2) Be careful not to damage his main vessels, the muscle fibres of his tibialis posterior, or his periosteum.

Using finger dissection, a Langenbach retractor, and if necessary scissors, free his tibialis posterior, until it will lift up and roll easily round the edge of his tibia in an oblique direction towards the base of his fifth metatarsal (which it will usually reach), crossing the centre of his leg about 4 cm above his ankle joint. Enlarge the tunnel if necessary.

When you have freed the tendon sufficiently to reach the dorsum of his foot, clamp its distal end with two Kocher,s, and divide it between them. Pull the two slips apart into a ''Y' with 6 cm arms. To prevent them separating any further, put a stitch where they meet, so that it will lie inside them when they lie together (G).

If his tibialis posterior will not reach the dorsum of his foot, check that you have freed its belly sufficiently.

Pass long Kocher's proximally, in the midline of his leg, from Incision Four for about 10 cm, and then deviate towards the proximal end of Incision One. Pick up both slips of his tibialis posterior, and pull them through on to the dorsum of his foot.

Pass the Kocher's from Incision Three to Incision Four. Pull one slip of tendon into Incision Three and leave the other one in Incision Four. Keep a Kocher's on each slip.

Pass your finger along his tibialis posterior tendon to make sure it lies easily in its new bed, that it runs smoothly round his tibia, and that no fascia obstructs its direct pull.

Use everting monofilament sutures (4-7) to close Incisions One and Two, without closing his deep fascia.

Put his foot on the positioning splint, to hold his knee at 80[nd]90[de] of flexion, and his ankle at 20[nd]25[de] of dorsiflexion, with his foot everted. While you adjust the tension in his tendons, ask an assistant to hold his foot in this position; or tie it to the foot splint with sterile bandages.

CAUTION ! (1) Don't let his foot invert. (2) Get his heel into the angle of the board.

Through Incision Three, place a Kocher's across about a quarter of his tibialis anterior tendon 2 cm from its insertion. While your assistant holds the distal part of this tendon tense, use a No. 15 blade to make a small longitudinal incision in it (Stab One), just distal to the Kocher's. Push a haemostat into Stab one, enlarge it a little and pull the slip of tibialis posterior tendon through it. Make Stab Two at 90[de] to Stab One 0.5 cm distal to it, and then pull the tendon slip through that. Make Stab Three 0.5 cm further distally again, and pass the tendon through that, as in H, Fig. 30-11 (if the tendon is not long enough, two stabs will do). Don't suture this ''weave' yet.

Turn to Incision Four.

THE FIRST METHOD is indicated if he has a peroneus tertius of suitable size. Holding the distal end of his tibialis posterior tight in Kocher's, weave the distal end of his peroneus tertius through it, in the same way that you wove his tibialis posterior through his tibialis anterior. Make Stab One in his tibialis posterior about level with the proximal end of his fifth metatarsal, just distal to his extensor retinaculum; make Stabs Two and Three more proximally. When the two tendons are woven together, work them along one another, until there is no slack tendon. Then, holding both firm so that they are just in tension, with his foot on the positioning board and his ankle everted, join them with 6 small sutures, passing through a little of each tendon, as in D, Fig. 30-11.

CAUTION ! As you suture the tendons, make sure they lie in the line of the pull of tibialis posterior, and are not raised away from his foot. If they are not in this line, they will be loose subsequently.

If there is spare tibialis posterior tendon left over, suture it to his peroneus brevis, or his extensor retinaculum, and tuck in any loose ends, so that they grow into the periosteum. If there is any spare peroneus tertius left over, stitch it so that it cannot attach itself above his ankle and limit movement.

Return to Incision Three. Move the woven tendons along one another until they lie snugly, and the tension in the medial slip is the same as that in the lateral one with his foot in the correct position on the splint. Suture the medial ''weave' in the same way.

CAUTION ! Don't make the medial slip too tight, or his foot will invert.

Check the position of his toes. While your assistant holds them as straight as he can, use a few small stitches to join the slips of his tibialis posterior to his extensor digitorum and extensor hallucis, as they cross.

Fig. 30-11 TRANSFER OF THE TIBIALIS POSTERIOR TENDON for foot drop in leprosy and other diseases. A, the medial side of the foot with the first three incisions. B, the incisions on the lateral side of the foot. C, tibialis posterior is being pulled up into Incision One. D, the First Method, using peroneus tertius. E, the Second Method, using the full length of peroneus brevis. F, the relationship between tibialis posterior and flexor digitorum longus. G, split and suture the tendon of tibialis posterior. H, weaving the tendons. Kindly contributed by Grace Warren.

THE SECOND METHOD is indicated if he has no peroneus tertius tendon, or it is too small:

If his peroneus brevis is paralysed (most patients), use it. Proceed as above until you have woven his tibialis posterior and his anterior together. Peroneus brevis is inserted into the base of his fifth metatarsal. Slip a blunt hook under it, and pull it, so that you can feel it under his lateral malleolus.

Make Incision Five over his peroneus brevis tendon as it passes under his lateral malleolus. Peroneus brevis lies deep to peroneus longus under his lateral malleolus, so you will have to hook out the deeper of the two tendons you find there. Pull it distally, and cut it off as far proximally as you can. This will leave the distal tendon as long as possible, without the need to make Incision Six. Return to Incision Four, you should be able to pull 8 cm of peroneus brevis into it. Weave peroneus brevis into the lateral slip of tibialis posterior and suture them as above. Close Incision Five.

If his peroneal muscles are still functioning (unusual), so that they had better not be sacrificed, take a free tendon graft from either: (1) his plantaris tendon from beside his Achilles tendon, or (2) a toe extensor. Weave and suture this free graft into his peroneus brevis as far distally as possible (to provide the best toe lift and eversion), and then into the lateral slip of his tibialis posterior, as described above. If you use plantaris and it is long enough, use it double for added strength (this method is not illustrated).

WITH BOTH METHODS check that the position of his ankle is satisfactory by lifting his leg off the splint, keeping his knee well flexed, and checking the angle of his foot and ankle[md]it should be in 15[nd]20[de] of dorsiflexion and show no inversion. If it drops to 10[de] or inverts, undo some stitches and tighten them. Don't worry if it is high (20[nd]25[de]): it will stretch later.

If sure you have cut no major arteries (usual), leave the tourniquet on until you have applied the cast. Otherwise, let it down, control bleeding by applying pressure for 5 minutes, carefully keeping his foot in position on the splint, and then close Incisions Three and Four.

CAUTION ! Don't plantarflex his foot while you do this.

THE CAST must keep his foot dorsiflexed and everted, and leave the dorsum of his ankle free. For this it needs a backslab and two side struts or braces.

Ask your assistant to stand beside the patient, facing the foot of the table, to flex his knee, and to flex and externally rotate his hip. His knee should rest on your assistant's abdomen. Your assistant's hand which is furthest from the patient should be flat on the sole of his foot (to avoid pressure areas), with its little finger over the head of his fifth metatarsal, its fingers straight, and with the patient's ankle 20[nd]25[de] dorsiflexed and everted. His hand must stay in this position until the cast has set. Ask him to support the patient's calf with the flat of his other hand, moving it as the cast is applied.

CAUTION ! The patient cannot complain of pain because his foot is anaesthetic, so pad his heel well, or he may get pressure ulcers.

With his foot in this position, firmly but not too tightly bandage on wool, with extra layers over his heel. Apply an 8- layer 15 cm backslab from the tips of his toes to his mid upper calf (your assistant's hand will be between the backslab and his sole). Secure the slab with a 10 cm bandage. Start at his big toe (A, 30-12), go across his sole medial to lateral, and pass three turns round his forefoot, just proximal to his toes. Then pass two turns round his lower leg (this will leave a strut of bandage at the lateral side of his ankle, and enable you to give his foot a good everting tilt as you do so). Then bring the bandage down the medial side of his ankle (to provide a medial strut) and run a turn or two round his forefoot. Continue until the bandage is finished. Apply another 10 cm bandage at the upper end of the backslab. Only now should your assistant remove his hand. Strengthen the side struts and the foot, but leave the front of his ankle and his toes open.

CAUTION ! (1) Make sure his toes are not dorsiflexed. (2) Don't leave finger depressions in the cast (F, 70-5). (3) Don't pull the bandages tight.

Fig. Fig. 30-12 A VERY SPECIAL CAST for a patient who has had his tibialis posterior transferred. A, the backslab applied with his foot dorsiflexed and everted. B, the lateral strut of plaster. C, the medial strut applied and the plaster being passed round his toes. Kindly contributed by Grace Warren.

POSTOPERATIVELY, raise his foot on 2 pillows or in a special splint (E, Fig. 30-10), so that his tibia is parallel to

his bed, but about 20 cm above it, and his knee is bent. If necessary (unusual in leprosy), give him morphine. Check the colour of his toes and his pulse hourly for 24 hours.

There will be blood marks on the cast. If the circulation to the toes is impaired, bivalve the cast, open it at least 1 cm, rebandage it, but don't remove it.

On Day 4 get him up on crutches, without weight-bearing.

Fourth week. (fifth week if physiotherapy supervision is limited). Readmit him, and bivalve his cast down the two sides, so that the struts are left attached to the posterior half of the cast (reinforced if necessary), which he can use as a protective resting splint while he is being rehabilitated.

CAUTION ! (1) Keep his foot dorsiflexed when you remove his sutures. If you don't, his flexors, aided by gravity, may pull away his healing tendons. Start exercises the day you remove the cast.

Fifth week. (first week after removal of the cast) Teach him to use his transfer in its new position. Lie him on his back (with his hips flexed and externally rotated, and his knees flexed), with both his feet in the frog position, so that the soles of his feet are almost touching each other. Ask him to do the inverting movement he did before surgery, his unoperated foot first. When he does that satisfactorily ask him to do it with both his feet together, and with his eyes closed (the movement produced by the transfer is not what he is used to seeing). Hold his operated foot with your palm flat on his sole, so that it cannot plantarflex. When he can do this without looking, let him look; the first movement may be very slight. Then let him graduate to doing it with only one leg.

Concentrate on getting him to dorsiflex his foot without using his gastrocnemius muscle, while trying to get a long, slow pull on his foot. Slowly increase the range and strength of the exercises with his leg horizontal in bed. Once he can do them, let him sit and watch them. After about 5 days, when he can move his transferred muscle easily and on command, sit him on the edge of his bed, and let him dangle his legs over it. Once he sits, he is lifting his foot against gravity, so he must not start doing this until he can isolate his transferred muscle and use it without gastrocnemius.

CAUTION ! (1) These exercises are fatiguing. During the first week, encourage him to do them many times a day for 5 minutes only, with 10 minutes rest periods with his foot back in its cast. (2) He must not plantarflex his foot: his strong gastrocnemius can easily pull the sutures out of his tendon transfer.

Sixth week. If he can isolate his transfer, and has good movement, let him stand with crutches or in parallel bars. Instruct him like this: ''Put your operated foot on the ground behind your other foot. Lift up your toes (by contracting your transferred muscle), lift up your foot as if you are walking, and put it down heel first in front of your other foot. Lift it up and put it back again behind the other one''. Progress to walking carefully with crutches. Make sure that every step uses the transferred tendon, and that contraction is held until his foot reaches the ground again. Let him walk for periods of 10 minutes and rest for 10 minutes.

Seventh week. While he walks with crutches, check that he uses his transfer with each step. Practise on steps, slopes and stairs. When he is confident, graduate to walking without crutches.

When he is not doing physiotherapy, bandage on the posterior half of the cast, until he learns to control his foot without trying to plantarflex it. He should be walking reasonably well at the end of the seventh week, and be able to discard his cast by day. Continue the protective splint at night until the end of the third month.

When he is off crutches, he can start rising on tiptoe while supporting himself with his hands on a table. His tendon join will gradually stretch, and his muscles will adapt to the range of movement required of them[md]provided you did not damage his periosteum, and so promote the formation of adhesions above his ankle.

CAUTION ! (1) Don't try to force his foot into plantar flexion: it will gradually come down as he walks. (2) He must not start plantar flexion too early, or he will lose the power of dorsiflexion. (3) Unless he learns to walk using the transfer with each step, he will not get a good gait; but even if he doesn't use it properly he should be much improved.

DIFFICULTIES [s7]WITH THIS TENDON TRANSFER The main difficulty is to persuade him to care for his feet for years to come.

If his TIBIALIS POSTERIOR TENDON IS SHORT, or is badly scarred, so that its whole length cannot be used, transfer what tendon is available, and insert it into his tibialis anterior tendon more proximally. Then attach his peroneus brevis as in Method Two, taking it long so that it bypasses the scarred region.

If the lateral slip of his TIBIALIS POSTERIOR WILL NOT REACH the lateral side of his foot without causing excessive eversion, and his peroneal muscles are not functioning, use a longer piece of peroneus brevis than that described in the second method. If necessary, there is 25 cm of free tendon. Don't make Incision Five but instead make Incision Six 10 cm long, starting 1 cm behind his lateral malleolus and running up his leg in line with his fibula. Cut down until you see his deep fascia, cut this in the line of the tendon, and find peroneus brevis (usually deep to peroneus longus). Cut it out of the muscle (which will not be used), pull it back into his foot at Incision Four, weave it into the lateral slip of his tibialis posterior, and repair Incision Six.

CAUTION ! Check his peroneal tendons behind his lateral malleolus, because peroneus longus and brevis are often attached together there. If necessary cut his peroneal retinaculum, behind but not below his lateral malleolus, so that you can pull his peroneus brevis down and out at the base of his fifth metatarsal without harming the tendon.

Weave, adjust, and suture his peroneus brevis to his tibialis posterior as in the Second Method. Then tunnel its free end back under his skin and, through a small J-shaped Incision Seven, suture it to the periosteum on the neck of his fifth metatarsal, as in E, Fig. 30-11. This will give him a better anterior lift if he has a very mobile foot.

If PRESSURE OF THE DRESSING causes sloughing and infection, dress and graft the bare area.

If his wound becomes INFECTED, his tibialis posterior tendon may adhere to other structures, or break. Splint his leg and apply a hypochlorite (''Eusol') dressing. Rest it until you have controlled infection, then slowly resume exercises.

If he DOES NOT USE HIS TRANSFER, he was not taught adequately. Good physiotherapy is essential.

If his TOES CURL UNDER HIS FOOT, ulcers may form and he may lose them. Keep exercising them to prevent stiffness, and correct them surgically if necessary.

If his FOOT IS SLACK ON THE LATERAL SIDE, and tends to invert, consider doing another operation to tighten the tendon, and perhaps bring peroneus brevis into the graft.