© Copyright Philip Evans


Repair depends on (i) blood supply and (ii) cells dividing.  

-    (i)  The blood supply brings in the increased blood cells to help to clear up the damaged area, and new capillary vessels that are necessary to provide the nutrition for the additional cellular activity.

-    (ii)   The cells of local tissue start dividing so that they can produce increased amounts of scar tissue.    Fibrous repair is by scar - although some tissues do partly regenerate new tissue, injured tissue never returns to its original state.    The fibrocyte (fibre-making cell) is both friend and enemy of the trainer/rehabilitator, because on the one hand the fibrin it produces does repair (= glue or weld) the injured area with scar tissue, but on the other hand the scar tissue can be excessive so that you finish up with a stiff joint.

If a joint is kept immobile while the scar tissue is laid down by fibrocytes, the joint will regain very little movement.    But if the joint is kept moving throughout the healing period, it will keep a achieve a much more normal movement pattern.

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R.I.C.E. After an injury it is usual to rest your injured joint for a few days - this should prevent any further bleeding from the torn blood vessels. An ice pack, wrapped and applied to the area, helps to reduce bruising and swelling, and also helps reduce the pain. Compression - usually some kind of firm bandage - also helps to keep swelling down and reduce bruising. Elevation - formally the ijnury should be kept above the heart (toes above your nose!), which will help to promote drainage from the injured region and thus keep swelling to a minimum.

After a further check to see that important ligaments are not torn, the patient is then encouraged to gradually mobilise more (keeping always within the limits of pain), until back to normal. The longer the joint is allowed to be immobile the less will the movement return to normal.

NB. It is often not possible for the rehabilitation team to get a joint back to full range of movement after bones are broken. Six weeks in a plaster-cast is a necessary period for the bones to repair. Often it is more than six weeks. But because the joint has been immobile for the six weeks, the repairing fibrocytes will have done their fibrin gluing only too well - the joint will be very stiff!

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Joint injury is usually caused by a force that twists or angulates it beyond where it should go, thus injuring the ligaments that normally prevent excessive range of movement.

An insignificant force will cause a .sprain. - here only a few fibres of the ligaments 'on guard' will be torn, and there will be a small amount of bruising and swelling from the torn tissues. There may be quite a lot of pain, though usually pain is not excessive. These joints are still stable and safe because their ligaments are substantially intact.  So they can be safely left to repair by body processes. Some kind of bandage is usually given - it will help others to see that the person is injured, may decrease swelling, and may splint the joint against painful movements when some everyday job is taken on. With a force as small as to only cause tearing of a few fibres of the joint, it is unlikely that any other parts of the joint are injured.

A larger force will cause a bigger injury That is why a cllinician may seem to be over-curious when finding out how an injury happened - she is probing to find out the size of the force and the direction it acted. Larger ligaments will be torn or even ruptured, the joint will be swollen with blood, and surrounding tissues may be also swollen from muscle or joint capsule injuries. If the joint is seen to swell up in 20 minutes, or within an hour, obviously something big has been torn, as it had a blood supply that also got torn.

The classic story of an anterior cruciate ligament tear in the knee is - 'I wrenched my knee, I heard a pop and it hurt like hell. Then it swelled up even as I lay there, unable to move it from pain'. By the time these injuries reach an injury clinician, the blood is filling the joint cavity under pressure. This causes a lot of muscle spasm which produces further pain. An injury like that is much more serious, because the ligaments that protect the joint and guide it through its 'envelope of motion' are ruptured, and the joint is like a dinghy mast without one of its stays - just waving about in the breeze.

On the day of injury, it is good practice to stabilise it to protect it from another wrench (plaster of a paris slab or a splint), and provide something that stops the person from having to use that joint - crutches for knee injuries, a sling for elbows or wrists.

In some joints the blood is also aspirated from the joint, notably the knee. Blood inside a joint is intensely painful, and may leave a residue of scar tissue behind, by the time that healing has been completed.  So even injured elbow joints are aspirated. Sterile techniques should always be used for joint aspiration as the consequences of infecting a blood-filled joint are dire. Because of this, and because a blood-filled knee suggests a serious injury, these joints may be admitted under the Orthopaedic team for examination under anaesthetic.

Healing in joints:

A minor sprain will repair by scar but the amount is so small that it appears to be back to the status quo ante ( as it was before). After a significant injury the joint is never the same again - tho' you might not know it !.

First, the torn ligament repairs by scar, which has less elasticity than normal ligament. Secondly. ligament may repair too short or too long. so that movements are reduced or excessive (See The Unstable Joint, Home Page) Then there is the blood that results from the injury, both inside the joint and around it - this ends up as scar tissue. An injured joint thus finishes up slightly stiff and slightly swollen.

And if the injury was so severe as to involve the bearing surface of the joint, with a sliver of articular cartilage chipped off, the chip can catch or jam between the joint surfaces. It may cause odd 'catching' pains during exercise, or even sudden locking of the joint, with excruciating pain.

The pain is caused by the sliver getting caught between the bearing surfaces. These bits of articular cartilage do not show up on an x-ray film, but even a typical story is enough to suggest to the experienced clinician that there is a 'loose body' in the joint, and refer to an expert for possible wash-out.

An expert and highly paid professional games player in some game that used to be a sport but shall be nameless, might be made to play a series of games when not fit (equals not healed yet), by using pain killing injections.  And thereby one of his joints might suffer a series of significant injuries. The result might be a combination of slightly loose ligaments (damaging the joint surface by sudden uncontrolled shear movements), and loss of joint receptor nerve organs (joint doesn't signal where it is, so tends to get injured).  Such a scenario can lead to early degeneration of the joint.  And where money is driving the so-called sport, it is only too likely that such signs are ignored or glossed-over.

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Ligaments hold joints together. They also guide the way that the joints move (equals 'control the tracking of the joint') .  Clinicians usually grade a ligament injury - this helps to decide the proper management, and the likely outcome, of the injury.

-    If completely torn (Grade III, ruptured), the joint is not properly controlled. This can lead to further joint damage.

-    If only a few fibres are torn (Grade I, sprained), the joint still has its mechanical integrity, and only the pain is a problem.

-    In between those two is the partial tear (Grade I). A ligament is torn, but it is not completely ruptured.

Ligaments do not have a large blood supply, for their material - collagen - is metabolically not very active. But they have quite enough blood, and a normal ligament will repair very well. The repair is not ligament, but scar tissue, so it is not the same as it was before the injury. But it is very difficult to find the difference six months after a Grade I ligament injury.

But a Grade III injury is different. During the period of healing, the mass of scar that is the ligament repair is laid down. Although the fibrin of mature scar never can have the same performance capabilities as the collagen it replaces, it should at least be not too long, or not too short. If too long, the joint will feel unstable, and may give way, and get injured again. (An unstable joint is an accident waiting to happen.)  If it heals too short, the joint will not go as far as it used to (reduced joint range), and this can harm part of the articular cartilage on the bearing surface - but it will cause nowhere near as much damage as an unstable joint . So the joint must not be allowed to get into a position where the scar tissue is stretched - it must not repeat the injury forces.

Then there is another factor in the mind of the rehabilitation clinician - that scar tissue can be encouraged to line up along lines of stress (just like normal ligament) by putting normal stress through the scar. In other words, by putting the joint through its normal range of movement. So during ligament repair, a joint should be encouraged to move, but it must be protected.

In some hospitals they put a tear of the inner ligament of the knee in a plaster-of-paris for six weeks: it stops tha pain, protects the ligament, and protects the joint; and it prevents the patient doing anything silly !. [I have watched a rugby man practising converting tries with a leg in a below-knee p;laster cast] Elsewhere they might apply a cast for two weeks and then fit a brace, a splint that only allows normal movement. But with very strict instructions.

A ligament injury in a finger is put in a strapping that binds the injured finger to its neighbour. This simple but elegant system allows normal movement - but at the same time protects against re-injury.

Some ligaments are so important that surgeons have learned to salvage them. The anterior cruciate rupture, driven by the value of top-flight soccer players, and the financial clout of skiers, has become the test-bed for all sorts of ligament reconstructions. And they do very well. But never think that it will ever be the same as it was before the injury. If you have one - a normal one, or a replacement - look after it!

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JOINT CAPSULE (including nerve and proprioceptive elements)

(In parenthesis, what 'proprioception means: It means 'joint position sense' and 'joint movement sense',  =  'knowing what you joint is doing'.)

Repair of injury is by scar tissue;  after repair of a joint we are usually left with one of two results :- a somewhat stiff joint, or a somewhat loose joint.  The stiffness comes from the scar tissue laid down by those ever-helpful fibrocytes (see Inflammation and Repair on the Home Page).  Laxity comeis from the original injury, which tore ligaments and left them too long.

Stiffness from scarring after repair has several effects:

-    First, the loss of joint range due to scar:  In this case, the articular cartilage at the very edge of the joint surface does not get its proper ration of nutrients - food and drink - delivered thro its letter-box. More formally,  articular cartilage fails to be nutrified by the sweep and squeeze of joint fluid if the joint surfaces cannot not regularily apposed (made to meet);

-    Next, scar on the inner surface of the joint capsule can rub on articular cartilage causing wear and pain (plica syndrome in the knee, and shoulder);

-    Next, injury to joint capsule tears nerves in the capsule.  When the nerve grows back, its little sprouts fail to find their way through the matted scar tissue, and so do not meet up with with their end-organs. This leads to a gradual loss of proprioception (joint sense). See how long any footballer in his mid-thirthies can stand on one leg with his eyes closed!

If laxity develops after injury, the joint is unstable. Poor tracking / control of joint surface cause the surfaces to shoot across each other (excessive shear) , with consequent surface injury to articular cartilage. This can be the beginning of joint degeneration.

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This is the bearing surface of the joint (see Cartilage, via Home Page) With the synovial fuid secreted by the joint capsule, it is excellent at providing a lubricated surface for the joint. But it has very poor repair capacity because it does not have a blood supply and contains very few cells.

Minor surface changes (fibrillation) may repair, especially in the young (who are remodelling as well as growing) but take three to six months. Trauma to deeper layers never repairs. But if if a joint that has surface fibrillation is subjected to continuous heavy use (as in a heavy labouring job, or from obesity), it can degenerate further.

Often the first complaint is stiffness after rest, say after sitting in a chair for a while. Later the joint also might ache after exercise, and so begin to be a nuisance. These symptoms are due to thinning and wear of the bearing surface of articular cartilage. At this stage the only objective finding by a clinician may be lipping - or bumpiness - of the joint margins, felt on examination. But this may not be so, or it may be difficult to feel.

If an X-ray is requested, loss of joint space will also be seen, showing that the space between the bony joint surfaces, which is occupied by the articular cartilage, has become thinner than usua. And that the articular cartilage is somewhat worn.  That is, provided that the X-Ray films are taken when weight-bearing. Many a sufferer with an acheing joint has been told there is nothing wrong, because there is nothing to show either on examination by the clinician, or on X-Ray. But the X-Rays were not weight-bearing films, and could not show the loss of joint space.

The articular cartilge of the knee can be injured by a meniscal injury - the fragment of meniscus, loose in the joint and causing occasional locking, hurts the soft bearing surface. That is why meniscal injuries should be arthroscoped early - to remove fragments. This happens of course in expensive, valuable f**tb*ll*rs, but not always to ordinary people!

A fracture that passes through the joint surface may heal leaving a 'step' in the bearing surface. In such cases some wear is inevitable, and joint degeneration may occur. Deep damage to articular cartilage will inevitably lead to joint degeneration, though it may be slow in coming ! Be aware that big injuries like a motor-cycle smash or a foot crushed by heavy machinery do tend to lead to joint wear because of the sheer amount of damage to the joint and its supporting structures. So look to the future and consider your rights - early!

Immobility is very bad for articular cartilage because its nutrition depends on movement ; and to be immobile with blood in a joint is looking for trouble, because the enzymes released by the dying blood cells can begin to dissolve away the articular cartilage.

But be of good cheer ! - there are many people with symptoms of joint wear that go on for years without going downhill. The recipe for keeping lower limb joints going is:

-    Exercise regularily

-    But do not overdo it

-    Respect your joint which is hurt, and take nice breaks !

-    Wear shock absorbing heels

-    Keep your weight down.

-    Take the joints into full range (in all directions) 2 or 3 times a day.

-    Keep off foods that seem to give you trouble (cheese, red wine, fruit acids)

If it all sounds very depressing, we must realise that most joints function with amazing reliability for many years. Here the message to make is - be aware of what can happen so that you can avoid unnecessary problems. Information is choice!

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Muscle injury always causes bleeding, because to do its job the tissue has many blood vessels. So a torn muscle causes a tender swelling, and the swelling can be big. A swelling made of blood is called a haematoma (L. haem=blood, Gk oma= swelling). The period immediately after an injury is very critical. The timing and style of rehabilitation after an injury is an area where where experience and expertise is priceless.

Usually the muscle should not be used actively for a few days, so as not to cause the fragile torn vessels to bleed again. Then after this inactive period, steps should be taken to try and disperse the blood. Even with the best care, the result will be limited regeneration of muscle, with some repair by fibrinous scar.   If there was a large haematoma, it will probably be changed into scar ('organised' is the jargon word = converted to scar tissue).  Hence, a torn muscle finishes up as a patch of scar in muscle; there may even be a dip in the muscle where the scar is.

Scar tissue is less elastic than muscle tissue, so cannot stretch so much when required to. Hence there is a tendency for an old muscle tear to get torn again, usually at the edges of the old scar. There may be repeated bleeds. Hence the well-known advice "Warm up well, then stretch your muscles !"

If the muscle bleed is in contact with bone, myositis ossificans may develop. This is new bone forming in the bleed/scar. The reason for this is that periosteum (L.peri = around, osteum=bone, the skin of the bone), is activated by free blood. It is the tissue that is responsible for changing (organising) the blood of a haematoma which surrounds a fracture,  into bony callus (weld). The periosteum does not distinguish between blood from a broken bone, and blood from a torn muscle. So a bleed in muscle at or near to its attachment to bone may become converted into a lump or spike of bone. This is called myositis ossificans - 'muscle being made into bone'

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TENDON AND SHEATH - Tenosynovitis.

A tendon (a leader) is the band of collagen fibres that connects a muscle belly to the bone.  You can see tendons going to your thumb and fingers on the back of your hand.  When a tendon goes round a corner it is bound down to bone, and passes through a lubricated tunnel. This tunnel is the tendon sheath. It has the same cellular lining as a joint (synovium) and the same lubricating fluid (synovial fluid).

If a tendon gets a knock where it is passing through a sheath, it will become inflamed (see Inflammation, Home Page), producing swelling, redness and pain.This is called tenosynovitis (tendon and synovium, inflammation of) . If a tendon is over-used (re-plastering and painting-out and re-tiling and and re-flooring the ktichen for an in-law visit afer Easter) it can also become inflamed. And in both those cases, if it used the next day it will not have had time to repair, to 'settle' . If the tendon cannot be rested (expensive f**tb*all*rs again, but also people with a hard job that supports a mortgage and a family and possible another family) each day's work will make it more inflamed. Until eventually the pain stops the work.

Where tendon goes round a sharp bend, almost always in a tendon sheath, it is especially laible to get tenosynovitis.. If this happens again and again, the repeated inflammatory response results in scar tissue; scar tissue over the tendon, and scar tissue lining the sheath.   The scar tissue can strangulate the blood vessels that pass to the tendon, leading to poor blood supply to the tendon. This can lead to degeneration inside the tendon, possibly with pain.

An achilles tendon like this will feel thickened, and the thickening may be painful. Later, it suddenly breaks.   These ruptures can take a long time to to repair - because the blood supply is poor. If a person works very long hours at some job - say, a darts marathon, or scraping down a wooden boat - it is very probable that there will be one very sore wrist in the next morning !   In other words, the wrist is probably inflamed, and needs a rest to settle and repair itself. But if then the person has to do a normal day's work for the next few days, the inflamed wrist tendons may get more inflamed in their sheaths, resulting in tenosynovitis (tendon, sheath, itis). Tenosynovitis can also result from a kick on the front of the ankle (which injures the tendons and sheaths) followed by a game of football. Other causes are - extra long hours 'on the line' - at turkey factory or shirt factory , overbooking on an orchestral tour, and typing all night to get a document out by a deadline.

There is pain and swelling locally, with redness and warmth around. There may be a rubbing feeling, like sandpaper, that can be felt by the clinician. The jargon name for this is 'crepitus' , and it is caused by the new fibrin rubbing between tendon and sheath. To give the joint any chance of getting better, the inflammation will need

(i) rest, usually in some kind of splint or cast that prevents movement,

(ii) some kind of anti-inflammatory medicine.

Not easy for the patient, when no work equals no money. This problem can become long-term (chronic), and then becomes very difficult to treat. The tendon sheath may become lumpy or thinned, and the sheath scarred and tight. This is called 'stenosing tenosynovitis'. This state occurs most commmonly in the thumb tendons. If it is serious it can be relieved by an operation.

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Just to mention that bleeding spreading outwards from a traumatic accident or an orthopaedic operation (similar thing really) will cause scar tissue to form:

(i) As thickening on the inside of joint capsules,

(ii)In tissue planes - between muscle and around tendons - and

(iii) Around nerves.

(i) and (ii) cause loss of joint range from either capsular or muscle shortening; (iii) causes diminished blood supply to the nerve, leading to pain in the nerve, scarring inside the nerve, and lack of elasticity in the nerve: This used to be called Adverse Neural Tension, is now pathological neurobiomechanics. It is very much a Physiotherapy Concept.

Scar tissue can result from inflammation anywhere. One other site where it can prove to be painful is where tisue planes rub over each other. This can happen around the shoulder joint, around the shoulder blade (scapula). Here the musc;les on the scapula are rubbed over by the musc;les to the arm, and muscles under the scapula are themselves rubbing over the muscles on the chest wall. Usually only athletes, preparing at full stretch, will run into this problem, but it turns up also in body-builders, oarsmen and racquet sportspeople.

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Damage to the I/V disc can happen suddenly from lifting heavy weights wrongly, or as part of a whiplash injury. It can also ocur slowly over time, in the form of 'creep' or lengthening of the disc fibres, from repeatedly turning or stooping over a long period. It can ocur as a comploication of Rheumatoid Arthritis.

The I/V disc is made of strong tapes of collagen fibres wound round a central core of soft cartilage. It is very strong, but it has no blood supply, except at the very edge of the disc. Having such a minimal blood supply, epair is slow and poor, (some say non-existant) by scar.

The disc is the main thing holding one backbone on top of the next.   When it has been injured, there is a tendency for the bone above to slip around very slightly on the bone below ('unstable motion segment'). There may be very little movement, but it is not as stable as it was before the injury. This is why, after a back injury, strengthening of back muscles is encouraged. Strong back muscles will help to stabilise the back. and compensate for the slight instability.

Instability is often found in I/V discs in the neck, caused by whiplash injuries or other neck injuries. The motion segment then develops further pressure on the little facet joints of the neck, and the nerve root may become compressed.  Pain is the chief complaint.  This problem can be helped a lot by simple measures.

-    First, a soft neck collar can help, provided it is properly fitted - it should prevent the sufferer from turning the head to look over the shoulder.

-    Next, advice on posture - usually the chin can be pulled in, and back of the chest straightened.

-    Plus exercises to strengthen the neck muscles.

These simple things will clear most neck pains, but any Physiotherapist or Osteopath will advise. See - Treat Your Own Neck by Robin McKenzie, ISBN No 0 473 00209 4.

Ligaments in the back can become stretched when we have to stoop for long periods, or hold a twisted or turned posture. Hanging on the ligaments by stooping for long periods will cause the collagen fibres gradually to lengthen;  lengthened ligaments mean less stable joints;  instable joints means significant injury can occur from insignificant effort. Hence poor work practices or bad ergonomic postures at work can be the precursors of injuries at home or in sport. They can be encouraged to repair by avoiding such movements, and again by building up the back muscles.

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Bone repairs well, as it generally has a good blood supply.  A broken wrist will take about six weeks to repair, a femur about 3 months. The humerus or tibia of a two-year-old will heal in 10-14 days. The wrist of an inactive 80-yr old may take 10 weeks.

At a fracture, the bone bleeds, so that the two ends are surrounded by a fracture haematoma (haem = blood, -oma = swelling). This is invaded by bone cells that convert it into callus (a sort of bony weld). If the fracture has put the bone ends out of line, so that the limb is bent or twisted, the clinician will arrange for this to be put right (manipulated, reduced). See Fractures, on the Home Page.

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When a nerve has been torn or cut, it does not repair very well - even with the best plastic microsurgery a one-third recovery is ratd as good. But if the nerve is not interrupted (not torn or cut) recovery can be very much better.

Nerves carry motor impulses out to muscles, and sensory impulses in from various sensory end-organs (say, for touch, hot-and-cold, or joint position).  Nerve injuries usually are part of a major injury, but we know that they are also damaged as part of a so-called minor joint injury as well.

The very worst nerve injury is when the back is broken, producing an injury to the spinal cord and thus paralysis. Another scenario is the high-speed shoulder injury, maybe from a motor-cycle accident or steeplecase fall, where the nerves to the arm are injured, as well as the shoulder joint. But in a significant joint injury - say a twisted ankle where there was swelling and bruising from toes to above the ankle - there will be tearing of small nerves as well as the injuries to the joints.

If a footballer injures his ankle or knee repeatedly, the small nerve injuries build up, and the joint may keep getting injured because of poor nervous contro. l Recovery in all these nerve injuries depends on many factors (see Fundamentals here - top), but chiefly on the amount of damage the nerve has sustained. Nerves can also be hurt by anything that cuts down their blood supply:

There is a condition called 'Saturday Night Palsy' by A & E staff :- The patient comes in on Sunday afternoon saying that their wrist and hand won't work. They say they got in late the evening before, and slept in a chair downstairs (afraid to wake the wife ?) with their arm over the back of the chair.  What has happened is that the normal blood to the Radial Nerve has been reduced, byu compression against the underlying bone.  So part of the nerve has become damaged, - there is radial nerve injury. The muscles at the back of the fore-arm, supplied by the radial nerve,have lost their nerve supply, and there is consequent 'wrist drop'. If the person was dead drunk, or drugged, or both, and did not move for 4-6 hours or longer, damage can be almost complete and permanent;   if for less than an hour or two, considerable recovery is possible.

Nerve injury is a major part of Repetitive Strain Injury (or Cumulative Trauma, see Clinical Orthopaedics and Related Research June 1998 - Cumulative Trauma Disorder of the upper Limb. There are eleven papers in the book). The over-use induces inflammation (see Home Page) and scarring, which over a long period will result in decreased blood to the local nerves. Same story as with tendons. That can produce pain, weakness and loss of sensation in the territory that the nerve supplies.

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Nerve injury is graded

-    merely bruised,

-    partially cut, and

-    total separation of the divided ends.

Note that this can never be an exact science because (without operating) the clinician can only guess at the extent of the damage from his tests.

(i) Slight swelling around the nerve impairs its function minimally and temporally : thus tingling in the hand is common for a day or two after a wrist injury.

(ii) Bruised, but sheath and fibre both not divided: Temporary loss of function only.

(iii) Sheath is damaged but fibre intact: Nerve fibre dies back a short distance and then re-grows down. May encounter scar at the injury site.

(iv) Nerve is totally divided - both fibre and sheath: Here the fibre dies back to the back or spinal cord and grows back at 1mm. a day. The fibre may on reaching the injury site find scar tissue blocking its passage,may grow down the wrong sheath to the wrong end-organ, so recovery after injury is variable.

Nerves have a reputation for recovering poorly, and if a major nerve injury has to be left to mend as best it can, recovery would be from 5% to 20%. A chainsaw hand injury repaired by plastic surgery would hope to get 25% and be happy with 40%. But after a clean cut by glass or a blade, with appropriate plastic surgery,l return of functioncan be 50% to 75%.  It is the amount of nerve damage at the time of the injury, that decides the final loss of function.

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After injuries, scar tissue may collect into palpable lumps under the skin or on bone. Patients may not realise they are there until they first feel them six months later. This can be worrying for patients who may wonder if these lumps are dangerous. The commonest pace to find lumps of scar is under the point of the elbow, where they are known as melon seeds. But any injury that took a long time to resolve will be thickened by scar, most typically - fingers.


Clinical Orthopaedics and Related Research June 1998 - Cumulative Trauma Disorder of the upper Limb.

Treat Your Own Neck by Robin McKenzie, ISBN No 0 473 00209 4.

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© Copyright Philip Evans