This is an excellent paper signed by W.S.C. Copeman about the role of the fibro-fatty tissue in certain “rheumatic syndromes”. He studied the relation of the fibro-fatty tissue to the clinical entity known as “fibrositis of the back” (also known as back mice) . But also other pain syndromes such dorsal pain or knee pain. He states that the etiopathogenic mechanism implies OEDEMA OF THE FIBRO-FATTY TISSUE. Copeman hypothesizes about the possible cause of this oedema as a probable endocrine disturbance.
Notes on the article:
Fibro-fatty Tissue and its relation to “Rheumatic” Syndromes
British Medical Journal. 1949; 2(4620): 191-197.
In this article, Copeman exposes his observations that the pain occurring in fibrositis is related to “A PAINFUL DISTENSION OF FAT LOBULES within a confined space”. He states that the fat tissues of the body are subject to pathological variations that cause pain usually labelled as “rheumatic” or “fibrositic”. If this occurs in the neighbourhood of joints, the condition is often wrongly termed arthritic. Copeman noticed that the OEDEMA showed NO SIGN of being inflammatory in nature.
Sometimes the flaw occurs in the fibrous covering (as the fascia), resulting in herniation of the enclosed fat lobule into an adjoining layer (herniation may be of 3 types).
The origin of swelling may be endocrine and the direct effect of cold may unmask it.
The concerns of Copeman: “to turn over a fresh page?”
Just at the beginning of this article Copeman states:
“If the observations I here put forward are correct, we are now in a position to TURN OVER A FRESH PAGE so far as our conception of certain of the so-called rheumatic syndromes is concerned”.
The concept of “fibrositis”
Copeman mentions that although fibrositis is an accepted entity, its pathological foundations are slender. Mainly based upon the theories of Gowers (1904), the histological studies of Stockman (1920) and the suggestion of Eliott (1944) regarding muscle spasm as a cause.
Copeman states that Stockman defined fibrositis as
“a condition of chronic inflammation of the white fibrous tissue of the fascial aponeurosis, sheaths of muscles and nerves, ligaments, tendons, periosteum, and subcutaneous tissues occurring in all parts of the body and giving rise to pain, aching, stiffness, and other symptoms, the result of preceding general infections or local inflammations or injuries”.
He says that in 1949, fibrositis was defined as an “idiopathic disorder of the soft tissues chiefly characterized by pain and tenderness, which may be local, widespread or referred, and it is often associated with muscular spasm.
Nature of the pain in fibrositis: “the intriguing trigger-points”
Copeman refers to the work of Lewis and Kellgren that pointed out that the pain in fibrositis generally has its origin in certain focal points and that is referred according to a segmental plan. This referred pain can be situated at a considerable distance from its real origin. These “trigger-points”, which are generally termed “fibrositic nodules” when they are palpable, are definite objective clinical entities”. When the examining finger finds them, the patient winces involuntarily. They are not just tender spots, but painful points that can refer the pain.
The existence of these trigger-points was then well recognized by its therapeutic success after local analgesic injection.
Non-tender palpable nodules are common but are not significant from a clinical point of view.
Aetiology of trigger-points and nodules
In 1943, he observed that the pain that accompanies most pyrexial illnesses is of the same nature and pattern as in fibrositis. Although the pain disappears after pyrexia, the tender trigger-point may persist in a proportion of cases unknown to the patient.
The trigger points can be REACTIVATED by recurrence of pyrexia, even if is due to a different cause. This suggests that these trigger-points can be “sensitized” earlier in life in the course of an attack of influenza or of exanthemata.
The nature of the lesion may be a RECURRENT OEDEMA PAINFULLY DISTENDING CERTAIN FAT LOBULES IN THE DEEP SUBCUTANEOUS TISSUES. Also trauma and cold can cause similar lesions.
Fibrositis due to OEDEMATOUS changes in the fibro-fatty tissue in certain sites
Method of investigation
They were first interested by the occurrence of “fibrositic” pain of lower back pain in otherwise healthy young soldiers. They measure the site of these trigger-points or nodules in a large number of sufferers; and then plotted a pain chart.
Then they also systematically dissected every patient who died in hospital to study these areas. The pain charts were found to outline the erector spinae muscles, the crest of the iliac bones, and the sacro-iliac joints. And they also corresponded with areas in which residual fat occurred even in patients with cachexia.
No clear evidence of pathological change could be found in fibrous tissue or muscle in biopsy material. Notwithstanding, while examining the deeper layers of fat in the neighbourhood of the trigger-points, they noticed a “curious herniation of a large lobule of distended fat through a defect in the deep fascia“.
In a later biopsy of an easily felt tender nodule, they noticed that it was an OEDEMATOUS-LOOKING node of fatty tissue lying among superficial fat of the upper buttock, but with a PEDICLE which could be traced down to the layer of fat lying beneath the deep fascia.
Fatty structures in the fibro-fatty tissue as a site for painful lesions
-In the paper of 1944, they described that the “fibrositic lesions” occurred in certain areas of “residual fat” that even in cases of extreme “cachexia” can be observed.
-The colour of this fat in such cases was darker or pinker than ordinary fat.
-In two cases of dissection the pedicle of a superficial fat hernia could be traced to the paranephric fat mass.
This suggested to them that this tissue in the lumbar region might bear some relation developmentally to the primitive renal fat gland (in rats, according to Hammar, this fat is of darker colour).
-The well-marked area of residual fat which lines the rim of the ilium may not be covered by this hypothesis, although another primitive fat organ is described in the outer groin in some textbooks.
-The largest of fat-organs is said to be situated between the scapulae a position which seems to correspond with that of our “dorsal fat-pad“.
Normal anatomical disposition of fat and the fibro-fatty tissue
-Copeman starts saying that NOT much information is found in textbooks.
–Subcutaneous fat exists throughout the body although its distribution is not uniform.
-In certain location fat collects more abundantly. Then, it forms a layer beneath the reticular layer of the corium, where it is laid down in the subcutaneous areolar tissue -panniculus adiposus-.
This areolar tissue forms a THIN, INDISTINTIBLE FIBROUS CAPSULE round the large lobules, where the fat is lobulated.
The lymphatic vessels serving the fat accompany the blood vessels in very close relation as they enter the lobule.
-There are numerous sensory nerves to the blood vessels, and possibly to other structures of the lobule. And sympathetic nerve fibers that run to the fat cells control the function of storage and yielding.
-Where the skin is thicker and less movable, the reticular layer is fixed to the deep fascia by numerous stout fibrous bands (reticulum cutis), the space between being filled with firm fat-clusters (this occurs mostly on the posterior aspects of the trunk and upper and outer aspects of the limb).
Pathological herniation of fat lobules, fibro-fatty tissue nodules
-From previous work they observe that the fibrositic trigger-points were related to the basic fat pattern.
-When they explored surgically, they observed “herniation of DISTENDED FAT LOBULES through deficiencies in their investing fibrous covering”. Removal or DISRUPTION of this hernia provided pain relief.
-Histological examination of the removed material showed “oedematous normal fat“.
In the lumbosacral region they found 3 types of herniae:
–Foraminal (foramina in deep fascia of the sacrospinalis muscles (along which the artery, vein, and nerve pass)
Copeman published 22 selected cases in which removal of the fatty hernia resulted in pain relief in an article in 1944, Herz 1945, from Cleveland, published 2 further successful cases.
Lesions other than herniation occurring in fat of normal distribution
A-Upper dorsal region:
-The skin is six to eight times thicker in this situation. There are islands of fat in the reticular layer of the corium of patients suffering from panniculitis.
-In the upper back the fibrous projections between the corium and the deep fascia normally form a series of honeycomb-like compartments that are filled with vascular fat.
-The axes of these “cells” are found to be roughly parallel with the tension (cleavage) Langer’s lines.
-This structure is particularly noticeable in the upper back area, and they called this diamond-shaped area the “dorsal fat-pad“.
-It is one of the common sites of fibrositic pain; it corresponds fairly accurately to the trapezius muscle that lies beneath.
-When painful nodules are palpable, they are seldom fibrous in nature. Pathological findings of the biopsy consists of fatty contents of one or more of these honeycomb-like compartments, swollen and under tension.
-Tension is shown by the fact that if incision is made at right angles to the lines of tension in the skin, the wound will gape and present above its surface.
-It is also shown by the peau d’orange if it is compressed laterally.
-By means of deep massage, some of these nodules can be “rubbed away”. Herniation is uncommon owing to the density the compartment walls.
-Copeman emphasized that the clinicians seem to be unaware of certain LOCALIZED COLLECTIONS of fat in CERTAIN JOINTS: particularly knees and ankles (and these may become painful without the joint necessarily being affected). And then an appropriated diagnostic of arthritis is often made.
a- The PATELLAR FAT-PAD:
A normal fat pad exists between the joint and the patella.
-These INFRAPATELLAR pads will often become tender and painful without the joint itself being affected, particularly around the menopause.
-This can give rise to: the sensation of grating on movement (which is considered to imply arthritis wrongly).
-A fold -called the infrapatellar synovial fold- extends posteriorly from the apex of each fat pad to be attached to the femur inside the joint cavity (then, in certain cases, it could derange the intra-articular function)
b- The POPLITEAL FAT-PAD:
Copeman noticed that this pad has not been described as a separate entity. Nonetheless, it is present in more than 80% of normal people over 40 years of age. It is usually wrongly mistaken as bursal enlargement.
It is sharply limited:
-Lower margin=upper crease of the popliteal skin
-Outer border lies roughly parallel with the course of the semimembranousus muscle.
-Upper border (when the pad is large) is delineated by another crease, which develops in these circumstances.
-The inner border lies to the outer aspect of the midline.
-This fad pad lies between the superficial and deep layers of the fascia covering popliteal space.
When large it distends the skin, although the cause of pain seems to be the distension of fat itself.
Full flexion of the knee-joint, by compressing may give rise to pain.
C-The sacral fat-pad
-Observed in 10% of normal persons. Very similar to the dorsal fat-pad. It’s smaller than the sacrum, and lies over it. It sometimes enlarges painfully as an isolated phenomenon, but it is more often associated to panniculitis (with or without obesity).
-Two other fat-pads exist
(a published description of which could not be found by Copeman).
–First=> dorsal surface of the basal phalanx of the big toe, where “male hairs”. It seems to be designed to buffer the strong action between the tendon of extensor hallucis longus and the skin. It enlarges in cases of gout.
–Second=> the ankle joint. Medially between the malleolus and the heel, roughly over the flexor retinaculum, whilst on the fibular side one lies over the stem of the inferior extensor retinaculum.
–A further fat-pad=>develops over the adductor tendons of the thigh at their pubic origin, in cases of obesity, and can be very painful.
Clinical effect of altering volume and distribution of body fluids
Copeman observed that increased fluid tension in certain tissues causes pain. Then he thought to relieve the pain by reversing this process.
-They carried out an experiment (Copeman and Pugh, 1945) whereby 22 cases of fibrositis were selected. They induced the state of clinical dehydration; they also added electrolyte to the extracellular fluid to increase its osmotic pressure. Of the 22, 13 were completely free of pain for variable periods. They thought that the experiment confirmed the mechanism of pain.
Relationship of panniculitis with fibrositis and the fibro-fatty tissue
-According to Stockman pain of unknown origin occurring in mesodermal tissue was always due to inflammation of the white fibrous tissues named as fibrositis. Pain from distending subcutaneous fat lobules can be classified under this heading.
-When pain of this type occurs in abnormally deposited fat, however, it will be referred to as panniculitis. This was described by Stockman (1911) and Telling. It was defined as “a chronic inflammation of the areolar tissue of the panniculus adiposus, including the small nerves and blood vessels”.
-Panniculitis is a common condition, which is insufficiently recognized as a cause of pain, which is not infrequently labelled “psychogenic”. Copeman’s investigations showed “non-inflammatory reaction”, but oedema of the normal fat deposits.
-The regions of the body encountered with panniculitis are: upper dorsal region, upper and outer aspects of the limb, around certain joints (knees, elbows, ankles…).
-Panniculitis is often associated to obesity. But sites of pain are confined to those certain regions mentioned above.
-Maybe in other sites the fat is less lobulated; in abdominal wall, no fibrous fascia or capsule is present to limit the distension of the fat if it becomes oedematous. Herniation of fat lobules is common in association with obesity.
-“Adiposis dolorosa” is just an entity with more generalized areas of pain, but the underlying cause of pain may be a non-inflammatory oedema. Dercum’s mentioned in 1892 that “occasionally very severe paroxysms of pain occurred, and these coincident with temporary swelling and hardening of the fat masses“.
Panniculitis of the upper dorsal region
-The “dorsal fat-pad“, which has been described as the seat of local lesions in fibrositis, is involved in cases of panniculitis.
-The tissues are sometimes excessively thickened and the subcutaneous tissues cannot be lifted between the finger and thumb.
-It is sometimes concentrated round the base of the cervical spine “the buffalo hump”.
Panniculitis of the upper and outer aspects of the limbs
–Tender nodules can form along the outer aspects of the thighs, often in association with enlargement of the peri-articular fat-pads of the knee.
-Pain is often diagnosed as “fibrositis“.
-They did biopsies and dissections of these nodules.
-The usual situation of these localized collections of fat is in the panniculus adiposus, where certain portions of AREOLAR tissue seem to become more heavily charged with fat than others do. These portions appear to be more closely lobulated and independent of the average layer of fat at this label, although lying in it, and give the appearance of being small independent “mesenteries”, each with its own blood and lymphatic supply. There is also a large potential space between the superficial and deep layers of the fascia, which overlies the fascia lata of the thighs, and fat nodules sometimes form also in this space.
-If the lesions become painful, it is found that they have become circumscribed by adhesions that seem to prevent lateral extension of the fat mass. The pain is then due to distension of the underlying fascial walls.
-The cause of these limiting adhesions is unknown, it may be traumatic, but in many cases it seems to be related to MENOPAUSE. They may result from a drying up of the normal lubricating fluid of the fascia.
An abnormal fat-pad develops over the inner aspect of the knee-joints as a menopausal manifestation and perhaps precursor of ultimate osetoarthritis.
-It occurs as a prominent feature of general obesity at any age, and in adiposis dolorosa.
-The appearance of these abnormal fat-pads, which may become very large and pendulous, is well known.
-They are generally bilateral, although pain or tenderness is often confined to one side only.
-Posteriorly: they cover the lower insertion of the inner group of hamstring muscles, being separated by a definite sulcus near the midline of the popliteal fossa from the normally present (but probably enlarged) popliteal fat-pads described above.
-Anteriorly they are limited by the internal aspect of the patella, but often appear to blend lower down with the infrapatellar fat-pad.
-There is no accompanying sensory abnormality of the overlying skin, although it is often the seat of multiple stellate or spiderlike collections of thin superficial veins.
-Varicose veins and local thromboses are also a common association, as is spontaneous bruising.
-On palpation, distinct lobulation of the contained fat is easily felt and only certain lobules are tender. Different lobules can be affected in different days. So the condition can be presented as “SHIFTING OEDEMA that moves from lobule to lobule”.
-Excision of the painful fat-pad successfully relieves the pain.
-These pads cannot be considered lipomata, the fat is laid down in the reticular areolar tissue between the corium of the skin and the synovial capsule, into the folds of which lobules will often penetrate and adhere. It resembles a “mesentery“, forming discrete “clumps“, each with its own blood supply and lymphatic system.
-If these medial fat-pads attain a large size, they can interfere with knee normal function. The differential diagnosis of “arthritis” is often made. Specially interpreted with a radiological confirmation with normally occurring “age-changes”.
Aetiology of the fat oedema
-The cause of the oedema in fibrositis and panniculitis is unknown, but probably it may be a part of a general process.
-It may be a general dysfunction of fat-water metabolism. It is this factor that accounts for those rapid and otherwise inexplicable variations in weight that occur during the dietetic treatment of obese.
-The association of this syndrome with menopausal women suggest that it may be an endocrine cause.
-It seems that the endocrinologists accept that the excessive secretion of oestrogens in humans will result in water retention, which largely affects the fatty tissues.
-The fault may lie in the dysfunction of the ovarian glands or, more probably, further back in the pituitary or hypothalamus.
-Over-activity of the pituitary and the adrenal cortex is known to be associated with pregnancy and the climateric, and commonly results in obesity.
-Kling (1947) terms “juxta-articular adiposis dolorosa” (probably localized panniculitis) and states that no high degree of endocrine disturbance was found in his patients, although B.M.R. estimates were only markedly abnormal in one-third of them. He found evidence of increased tissue tension that causes pressure on the nerve endings and so gives rise to tenderness and pain (he failed to find evidence of interstitial inflammation of sensory nerves).
-It is known that there are disturbances of water exchange in general betoken dislocation of sodium balance (since all cell membranes permit the free passage of water but not of sodium and chloride).
-It is now believed that the water levels are controlled largely by activity of the hormone of the posterior lobe of the pituitary and the influence of the desoxycorticosterone fraction of the adrenal cortex.
-There may be a genetic factor involved since female cases revealed a history of a similar condition.
-It has seemed that in a large number of these cases cold has been the precipitating factor, but Copeman thinks that cold is merely activating a state already in being.
–Bazzett and his co-workers observed that a temperature gradient exists between the surface of the body and the deep tissues extending inwards to a depth of 2-3.5 cm range from 3-9ºC. Thus, the external environment must directly affect these tissues since the weather-sensitivity is known in this phenomenon.
Treatment options by Copeman
–DIET: If there is an addition of obesity, weight reduction needs to be faced. Even in patients who do not appear to be overweight.
–ENDOCRINE: Copeman suggest that in menopausal humans the endocrine treatment common in that time could be helpful.
–DIURESIS AND DEHYDRATION: By different common ways of that period.
–PHYSIOTHERAPY: Firm localized massage is used to disperse the swelling, if very painful at first, later it will become less sensitive. Previous exposure to radiant heat and infra-red rays will increase the patient’s tolerance. If the fat herniation has not become fixed by adhesions, reduction by massage may be possible.
–INJECTION: The object is to disrupt swollen fat lobule by hydrostatic pressure and so relieve the painful tension. Mere infiltration with anaesthetic will give temporarily relief only. They use a solution of procaine 0.5% in saline, and “teasing” with the point of the needle. They also use oily anaesthetic solution (benzyl salicylate) under pressure.
–SURGERY: Especially in well-chosen cases of irreducible fat hernia that cannot be disrupted. BUT it is sometimes very difficult to localize these structures of pain, since sometimes the herniation is multiple. In cases of panniculitis undercutting the painful area can relieve pain. Presumably the sensory nerves are cut in the course of this procedure.
-Other authors in America had published about similar findings: Herz from Cleveland and Hutcherson, in a paper read before the Association for Surgery of Trauma in July 1948. There are also several isolated operations among surgeons that communicate with Copeman.
- Copeman WSC. Fibro-fatty Tissue and its Relation to “Rheumatic” Syndromes. British Medical Journal. 1949;2(4620):191-197
- Stockman R. The Clinical Symptoms and Treatment of Chronic Subcutaneous Fibrosis. British Medical Journal. 1911;1(2616):352-355.
- Gowers WR. A Lecture on Lumbago: Its Lessons and Analogues: Delivered at the National Hospital for the Paralysed and Epileptic. British Medical Journal. 1904;1(2246):117-121.
- Copeman WS and Ackerman. Edema or herniations of fat lobules as a cause of lumbar and gluteal fibrositis. Arch Intern Med (Chic). 1947 Jan;79(1):22-35. PubMed PMID: 20283861.
- Herz R. Herniation of subfascial fat as a cause of low back pain; report of 37 cases treated surgically. Ann Rheum Dis. 1946 Dec;5(6):201-3. PubMed PMID: 20242353.
- Hucherson DC , GANDY JR. Herniation of fascial fat; a cause of low back pain. Am J Surg. 1948 Nov;76(5):605-9. PubMed PMID: 18891320
- Elliott FA. Aspects of “Fibrositis.” Annals of the Rheumatic Diseases. 1944;4(1):22-25
Published on March 2018
By Marta Cañis Parera