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Wolfgang G. H. Schmitt – Buxbaum,
Key words: fracture or overload reaction, predisposition to acute or chronic fracture, repeated minor injuries, march fracture, stress reaction, “insufficiency fracture”, remodeling zone, disproportion between load and load-bearing capacity, overload of the supporting apparatus, skeletal weakness, fatigue fracture on pre-damaged bone, Calcaneus, distal tibia, lateral Tibial plateau, metatarsal bone, Growing or mature bone, reconstruction zone, repair processes, growth plate, soft tissue edema, metaphysis, aseptic necrosis, Achilles tendon swelling, tendinitis,
Gentle therapy, scintigraphy, NMR, MRI, classic spin echo sequence, STIR sequences, T1, T2 sequence, fat saturation methods, gradient echo T2*, “T1-KM fat-saturated”, gadolinium-DTPA distribution, medullary edema, hyperemia, contrast distribution,
Please contact us if you have any suggestions or questions. (E-mail in the introduction of the homepage at the end). The aim of this article is to contribute to the understanding of the topic “MR of bones and joints”. It is suitable for beginners; no previous knowledge is required. Important information is repeated several times. No special attention has been paid to image quality. It was more important that the images be memorable. The following text first presents and discusses four characteristic cases, three classic overuse injuries and one interesting case from a differential diagnostic point of view.
This is followed by four brief descriptions of other overuse injuries to complete the picture.
In the case histories of such stress-related changes, psychological correlates are often found. For this reason, our MR image analysis is supplemented by an appendix: “Outline of Psychodynamic Changes in Overuse Injuries”.
Case 1. What is your diagnosis?
This is a 41-year-old woman who decided to do something about her health.
She bought a pair of expensive trainers and ran every other day on a 4 4-mile paved track in her home town. The first few times it was very difficult for her, but she soon made significant progress under the astonished eyes of her neighbors. This motivated her to try even harder. She was proud of her accomplishment..
However, after exactly two weeks, this success story was marred by discomfort in her right heel. Toward the end of the race, the symptoms increased to severe pain throughout the heel. Even at rest, she was no longer free of symptoms. The patient tried to run again, but stopped – very disappointed – and asked to be picked up by car. She then took a break from running.
The patient correctly identified the cause of her symptoms: “I was doing too much of a good thing – more than I could bear”.
Based on the history, it is very likely that the injury is due to overuse. There is no acute trauma, but there is unusual long-term stress; this history does not suggest infection, tumor or thrombosis. The exclusion of other causes encourages us to to the assumption of a “mismatch between stress and resistance”.
Dear friends, this is the most frequently visited case. There is also another contribution. “Osseous Insufficiency I” – less MR, more an overview of the whole complex.
Overloading of the bone has a confusing array of synonyms: stress fracture, march fracture. The many different names for the same thing show how difficult this is for medicine. None of these terms is wrong; they clearly indicate the genesis of the condition. I prefer to use the generic term: “ossicular insufficiency”. “Remodeling zone” is not a name for the disease, just a striking visual symptom. More on this later.
The cause of the disease is an imbalance between stress and resistance. This is also the cause of acute trauma! In our patient a particular mechanism of injury was at work in our patient: repeated small traumas. These alone would not cause injury; it is only in combination that they can cause damage. “Chronic trauma” is logically another synonym.
Depending on whether a growing or a mature bone is affected, the damage within this region is arranged differently: The following
The growing bone is particularly vulnerable: The growth plate (apophysis or epiphysis) and adjacent parts of the bone.
In adults, however, the zone of greatest vulnerability is in the shafts and bodies. – In the calcaneus, this is the corpus (sometimes close to the tuberosity, sometimes more in the central region). – –
Two days after stopping training, the x-ray showed no changes (yet).
An MR scan was performed two weeks later. By this time, the symptoms had improved significantly. In fact, they were surprisingly small compared with the marked MR findings. (Perhaps the MR findings would have been even more impressive a week earlier).
The diagnosis was
Stress fracture of the calcaneus. Of course, a number of other terms would also be correct: “overload damage to the bone”, “stress fracture”, etc.
Overloading of the bone has a confusing array of synonyms: stress fracture, march fracture. The many different names for the same thing show how difficult this is for medicine. None of these terms is wrong; they clearly indicate the genesis of the condition. I prefer to use the generic term: “ossicular insufficiency”. “Remodeling zone” is not a name for the disease, just a striking visual symptom. More on that later.
The cause of the disease is a mismatch between stress and resistance. This is also the cause of acute trauma! A particular mechanism of injury was at work in our patient: repeated small traumas. These alone would not cause injury; it is only in combination that they can cause damage. “Chronic trauma” is logically another synonym.
Which regions of the musculoskeletal system are affected by overuse injuries?
It is obvious that the weak points of the skeleton are affected first. More precisely, the weak points. In humans, there are several such vulnerable regions, known as “loci minoris resistentiae”.
But even within a given region, there are big differences in the pattern of infection:
Depending on whether a growing or a mature bone is affected, the damage within this region is arranged differently: The following
The growing bone is particularly vulnerable: The growth plate (apophysis or epiphysis) and adjacent parts of the bone.
In adults, however, the zone of greatest vulnerability is in the shafts and bodies. – In the calcaneus, this is the corpus (sometimes close to the tuberosity, sometimes more in the central region).
Two days after stopping training, the x-ray showed no changes (yet).
An MR scan was performed two weeks later. By this time, the symptoms had improved significantly. In fact, they were surprisingly small compared with the marked MR findings. (Perhaps the MR findings would have been even more impressive a week earlier).
The diagnosis was
Stress fracture of the calcaneus. Of course, a number of other terms would also be correct: “overload damage to the bone”, “stress fracture”, etc.
Figure 1a: Magnetic resonance STIR.
We see a sagittal slice guide, recorded as a so-called STIR sequence. In the STIR image, the fat is dark (due to fat suppression) and almost all the pathology is bright (due to water infiltration).
STIR images are not aesthetically pleasing, but they are excellent for quickly seeing where the disease is and how severe it is. Compact bone and the fatty marrow space are dark, only the pathological “increased water” shines brightly in this sequence. Let’s talk about “sequences” in general below.
Contrary to expectation, in this STIR image shown above, the tuber calcanei are intensely bright; this finding is in complete contrast to the dark signal in the neck of this bone and in contrast to all other (healthy) bone sections. The bright image signal must be some kind of water proliferation (oedema). In the nodule, the oedema has displaced the normal bone marrow. There is also (discrete) oedema in the soft tissues, for example in the subcutis over the Achilles tendon near the Achilles insertion. This soft tissue oedema also appears as a bright MR image signal.
The large ‘brightness’ in the bone – i.e., the (fat-displacing) oedema – is interrupted by a dark line.
You might think this is a growth plate, but growth plates are long closed by this age. Could this be where the fat is? So, the fat has not been displaced regionally? The T1 image rules out this possibility. More on this later. The x-ray (not shown here) will help. It shows a prominent zone of sclerosis, a “bright band” typical of intraosseous callus formation. Bone substance from a healing process – partly uncalcified, partly calcified – has replaced the bone marrow oedema. This dark line in the STIR image is a planar structure in the real world. It runs parallel to the posterior edge of the heel bone (see also the 8th and last case in this collection): There is indeed a growth plate. It looks very similar to the remodeling zone in the current case). The pathological process simulates, so to speak, a growth zone. – The classic name for this regional healing in chronic trauma is: reconstruction zone.
Figure 1b: T1
A T1-weighted image of this case is shown here.
In the T1 image the fat is very bright, the water (and therefore almost all the pathology) is dark.
Contrary to STIR, in this “T1” the fat (as I said – fat tissue dominates in the marrow) is bright. As already emphasized pathological process in the heel bone displaces the fat and makes the bone dark. This process, and therefore the “darkening”, extends to the entire heel bone, but is not uniform. Important definitions: Sequences are machine settings that measure specific physical tissue properties. Depending on the sequence chosen, these properties are translated into grey values in very different ways.
T1 is a classic spin echo sequence (the main family of sequences). Tissues with a high T1 relaxation time are dark and those with a low relaxation time are light. Where is “high T1”?High T1 is characteristic of almost all pathological tissues (neoplasia, inflammation, oedema).
T1 images are high contrast and aesthetically pleasing due to the bright fat structures.
STIR (1a ) is a “search sequence”, it comes from the second most important family of MR sequences, from Inversion Recovery = IR. For example: STIR, as in almost all other sequences, the compact bone is black due to the lack of signal.
Fat, on the other hand, appears completely different in STIR than in the T1 sequence mentioned above. STIR suppresses the image signal of fat very strongly; fat is dark. Apart from fat, STIR T2 has its own characteristics. Higher T2 is displayed brightly: “Water” causes a very bright image signal in STIR. “Water” also means watery tissue in any form: oedema (e.g., inflammation) or neoplasm. STIR is therefore sensitive to high concentrations of water and/or high levels of a specific water binding, ‘free ater’. Free water is typical of most diseased tissue. This sensitivity, together with fat suppression, often results in pathology being highlighted. There is no risk of the fat signal masking the water signal of a pathological process. However, fat suppression – here in STIR – is an obstacle to anatomical orientation. This makes STIR an excellent search sequence. It is very sensitive in finding pathological changes, but very non-specific. Because of its sensitivity, it can sometimes lead to overestimation.
How can we improve the specificity to distinguish the different pathologies? How this works in combination with other sequences will be shown later:
* Between effusion and synovial fluid,
* Between tumor and necrosis,
* Between hyperemia and abscess will be discussed later.
Note: STIR is very sensitive: The image signal with STIR is bright in almost all pathological processes. In T1, these “pathologies” are dark. The fat – and therefore the healthy fat marrow – is suppressed in STIR, so it is dark.
Both (fat and pathology) are shown in the STIR sequence in the opposite way to the T1 sequence.
What happens histologically in the “remodeling zone”?
The oedema is replaced by a water-poor, more differentiated and ordered, partly calcified tissue (healing). There is often a very bright STIR signal in the vicinity, indicating an active metabolic process preparing for healing.
In pathogenetic terms, this means that
The consequences of chronic trauma are compensated by regeneration and repair. In parallel with repair, correlates of damage – typical of chronic trauma – can be found.
Damage means oedema, hemorrhage and necrosis.
Repair means: granulation tissue and callus.
Soft tissue involvement is typical of chronic fractures.
Bones and soft tissues form a single unit. It is not surprising that the soft tissues “co-react”.
Now for more material on the first case:
Nun zu weiterem Material zum ersten Fall:
Figure 1c: T1 after intravenous gadolinium
The figure shows two difficult to interpret images: Both are T1 images, but they have a peculiarity. They were obtained after intravenous gadolinium administration. This dark appearance of the medullary canal doesn’t correspond to T1 at all? Fat is usually very bright on T1.A trick has been used in T1: The fat signal is darkened by “fat saturation”. Almost all pathological processes also appear dark in T1 (high water content = high T1 = dark image signal). So almost everything would be dark in this sequence. The “gadolinium-receiving structures” are excluded; they appear bright to very bright. Gadolinium shortens the relaxation time T1 of the tissue. This “short relaxation time T1” appears very bright in the T1 image. Here we have, in simple terms, a picture of the distribution of the contrast agent.
“T1-KM-fat-saturated” is similar to STIR, but only superficially (compare the images!).
MR sequences contain a lot of technical information. Some of the technical details simply have to be learned; don’t expect to be able to deduce everything logically.
In STIR we see the pathologically increased and altered water as a bright image signal.
In the “fat-saturated T1 CM” we see the contrast agent as a bright signal, i.e. the distribution and effect of the CM. This is a good measure of hyperemia and metabolic activation: Bright means “excitement”, activity.
Dark means ‘rest’.
In the calcaneus shown here, the dismantling and rebuilding process is enormously accelerated. Destruction and repair are booming herein the dark strip near the Tuber, peace and order – i.e., healing – have returned. The “fat-saturated T1-KM” (the last two pictures) should again be characterized in other words:
In T1, only the “fat” would be very bright; in this T1, the fat is suppressed. The image should look completely low signal and low contrast. But the contrast agent brings structure to the image; wherever it reaches, it causes a shortening of the relaxation time T1, which means a very bright image signal.
T1 time down = image brightness up
The increased metabolism goes beyond the bone and into the soft tissues. Too often we think in terms of organ systems that function independently and become ill independently. The soft tissues suffer along with the bones.
STIR and T1 fat saturated after KM often look similar, although the bright image signals represent something different. They are easily distinguished when pure fluid is present, which is bright on STIR and dark on any form of T1 sequence. This is discussed in more detail in the third case.
Briefly about the course:
As hoped and expected, the patient was completely symptom free after two more weeks. She soon resumed sports activities – swimming and cycling. A few weeks later she started jogging again, but with caution. She had made what sports medicine experts call a “training modification”; she had listened to an inner voice telling her to take a break; she did not deny these signals.
It is possible that the patient had a certain amount of pretense when she came for the MR scan. The positive thing was: She saw an active opportunity to counteract future false stress. She paid the price, but she learned. Some questions remain about the details of this incorrect loading: Could the wrong shoe construction have played a role, for example? Overloading after a new purchase or a change in training regimen is common. The whole length of the course is probably a particularly bad place to start training.
Case 2. Typical march fracture of one of the the metatarsal bones.
A 43-year-old patient decided to take up jogging because she noticed she was slightly overweight and had been diagnosed with elevated blood lipids. She ran every day for half an hour on hard surfaces in new trainers. It took a lot of willpower to keep her going. But she managed her self-imposed workload. After four days, however, she developed midfoot pain that forced her to take a break.
There was significant soft tissue swelling in the midfoot area. No swelling in the lower leg. Regular arterial pulses. No skin changes.
When there was still no improvement after ten days, an MR scan was ordered.
Figure 2 a: STIR; metatarsal IV
In the STIR (known as a typical search sequence), metatarsal IV shows a massive signal enhancement (bright!) in contrast to all other metatarsal and tarsal bones. Until proven otherwise, this is a medullary oedema. This is interrupted by a signal free “line” in a central zone of the shaft. The oedema also extends into the perosseous soft tissues of the metatarsus.
Other sequences also confirm the pathological findings; a gradient echo T2* (not shown) clearly shows a bright signal enhancement and associated soft tissue oedema.
Both sequences – STIR and T2* – show a low signal defect in the bone within the bone marrow oedema: the bright spongy space is interrupted by a transverse black line.
Figure 2 b: T1; metatarsal IV
The T1 image also shows this pathology but other image characteristics.. The normal bone marrow is bright on the T1 image (fat content). However, in this T1 image (top), the altered marrow of metacarpal IV is dark, as is the surrounding soft tissue. Something pathological (probably oedema) has displaced the fat.
Diagnosis: Typical march fracture of one of the the metatarsal bones.
Synonyms for “marching fracture of the metatarsal” are
* Stress fracture
* Chronic trauma without previous bone disease
* Overuse injury in healthy adults
The term “insufficiency fracture” is reserved for cases where the chronic trauma affects a previously damaged bone, such as in osteomalacia or osteoporosis.
All of these diagnoses, whether in healthy or diseased bone, have a general term: chronic trauma.
Another seldom used but very accurate general term is: osseous insufficiency.
The 2nd and 3rd metatarsals are even more commonly affected than the 4th metatarsal. In adult stress fractures, the shaft area is almost always affected.
In adolescents, however, the growth nucleus and growth plate appear to be the sites of reduced resistance.
The authors suggest that some “aseptic necroses” may be classified as “adolescent overuse injuries”.
Stress fractures are difficult to diagnose:
The pain often does not start during the overuse situation, but is delayed. Distraction, concentration and endorphin release may play a role.
Trauma as a cause of disease may remain hidden. This is especially true of chronic trauma. When we think of trauma, we associate it with an accident and don’t think of the prolonged accident: the overload. Such patients can be mistaken for those with tumors or infections.
In the appendix, we also discuss psychological links in the pathogenesis of chronic trauma.
Why does osseous insufficiency affect a particular side of the body? Why a particular region? – We can assume that the stress is particularly high in one region and that it is only there that the limit of tolerance is exceeded. The strain on a particular region is the “tip of the iceberg”. Extreme stress can also cause bilateral overuse injuries and injuries in more than one location.
This is more common in men than in women. Stress is demanded of men. Society (including sports medicine) suggests an “obligation to perform at a high level”. What is obligatory must also be possible. So many patients not only harm themselves, but also resist therapy that begins with accepting limits.
Good sports teachers control things by “training modification” and counteract unhealthy attitudes at an early stage.
The further course of this particular case of march fracture of the fourth metatarsal was very unspectacular. With care (and more appropriate footwear) the symptoms subsided within a few days. After five weeks, a cautious build-up of training was undertaken, which was tolerated without further symptoms.
The second and third metatarsals are even more commonly affected than the fourth. In an adult stress fracture, the shaft area is usually affected.
In adolescents, however, the growth nucleus and growth joint are the sites of reduced resistance.
The authors suggest that some “aseptic necroses” may be classified as “juvenile overuse injuries”.
Stress fractures are not easy to diagnose:
Pain often does not occur during the overuse situation, but is delayed. Distraction, concentration and endorphin release may play a role.
The cause of an illness may remain hidden as a trauma. This is especially true of chronic trauma. People associate trauma with “accident” and don’t think about the prolonged accident: the overload. Such patients may be misdiagnosed as having a tumor or infection.
In the appendix we also discuss psychological aspects of the pathogenesis of chronic trauma.
Why does bone insufficiency affect only one side of the body? Why only one region? We can assume that the load is particularly high in one region and the limit of tolerance is exceeded only there. The stress on one particular region is the “tip of the iceberg”. Extreme stress can also cause bilateral overuse injuries and injuries in more than one location.
Our first two cases are women; men are even more often affected. Stress is demanded of men. Society (up to and including sports medicine) suggests a “duty to perform well”. If it’s obligatory, it must be possible. As a result, many patients not only harm themselves, but also resist therapy, which begins with accepting limits.
Good trainers counteract this attitude early on by modifying the training program.
Case 3: Osteomyelitis after Schanz screw (thus not overuse damage!)
Case 3
Now comes a case that is not real “overload damage”! But interesting. Something similar is discussed in Artifacts II, Chapter 5: Septic and aseptic complications after injections and surgery. STIR and “T1 fat saturation” should be compared in more detail. We take a detour from chronic to acute trauma complicated by inflammation.
This 70-year-old farmer woman suffered a tibial plateau fracture. A “Schanz screw” in the distal femur had festered and was removed. Weeks later, an abscess developed in the soft tissue and bone. It was cleared out and filled with a chain of antibiotics. After another six weeks, this chain was removed.
Another four months later, the distal thigh was again very painful and swollen: no redness was visible; but there was an increase in temperature (37.9 °C). An MR examination was ordered.
Fig. 3 a – c
Three images are shown below, with
a. STIR being the topmost one.
b. .In the center T1 (without fat saturation)
c. The bottom picture: T1, intravenous Contrast application.
The latter sequence could be described in more detail as follows: A T1 image, but with fat suppression; As a further special feature, it is enriched with contrast medium and therefore all blood-perfused structures are highlighted very brightly.
All three images were taken using coronal slice guidance. Very similar characteristics can be seen as in the images of the first two cases.
The bone defect is clearly shown as in the STIR. However, this area is now filled by a partly dark, partly light structure. What appears bright in both STIR and T1 with contrast is perfused tissue. There is fluid inside: although it appears bright in the STIR, it appears dark in the T1 with and without contrast agent. It is most likely “liquid.” According to the clinical context, there is a lake of pus, i.e., an abscess.
At first glance, this T1 image wth contrast administration appears similar to STIR: here, too, the muscles are dark; The originally bright fat signal is suppressed by fat saturation and is therefore also dark. The fat is also suppressed in STIR – but STIR and “T1 (fat saturated after CM)” also have differences:
Liquid abscess material, i.e., the liquid (not supplied with blood) center of the lesion, is dark on T1 in contrast to STIR because fluids are dark on T1.
Thus, this last image allows an informative differentiation of:
- Abscess membrane (with a thick layer of inflammatory activated tissue)
- Pus collection.
Although none of the two components (1 and 2) were missed in the STIR, they were not differentiable.
This case therefore demonstrates the additional benefit of contrast medium (CM). KM results in a differentiation of the information from the STIR. The latter is very sensitive but non-specific.
In other words: T1 with CM: abscess/core: dark; Abscess/periphery: bright, easily differentiated
STIR: abscess/core: bright; Abscess/periphery: bright, both cannot be differentiated.
The next case of illness leads back to “chronic trauma.”
Case 4: Stress fracture of the distal tibia
Fig. 4a, STIR (short tau Inversion Recovery)
A 56-year-old dentist went on a very strenuous hike two and a half weeks before an MR scan. He had made a lot of plans, had to turn back because of the rain and ended up getting lost. So, there was a combination of factors that led to an unusual strain. A few hours after his return, he experienced severe pain in his distal lower leg.
The swelling and overheating of the soft tissues puzzled even his doctor. With a normal x-ray – under the question “Arthritis of a single joint? Tumor?” – he presented himself for an MRI scan. The blindness to his medical history is remarkable. The image on the left shows the STIR Sequence.
There are at least three peculiarities:
- The talus is not affected, nor are the parts of the tibia closest to the joint. With any form of arthritis, one would have expected a “bright signal” (=oedema) on both sides of the joint space in the STIR.
- A particularly bright line runs diagonally across the distal tibia; there must be a particularly large amount of “water” (or “blood”) here.
- The soft tissues – usually dark in STIR – are also very bright; pathologically, there is massive oedema.
In the STIR (picture above) you can see a “sensitive” highlight of the severe oedema in the muscles; This continues through a defect in the compact into the medullary canal. Is this fluid or inflammatory tissue?
Fig. 4 b, T1 (classic spin echo sequence)
The T1-weighted sequences are quite different from the STIR shown above: in T1, fat is very bright, free fluid (cerebrospinal fluid, urinary and gallbladder contents, slow moving blood) is dark. The good resolution provides wonderful images for studying anatomy. However, if you think that you can save a search sequence like the STIR with the T1 image, you are making a psychological and factual mistake:
Pathology on T1 is often darker than the physiological tissue, which is much less likely to set off the alarm bells but rather encourages overlooking. Particularly important are the cases where the above rule does not work so clearly; where the lighter image signal in the STIR shows an unexpectedly moderate reduction in T1. It is also possible that this decrease in image brightness is completely overlooked due to the window selection in T1. This could have happened in image b. Other difficult constellations are when the bright T1 signal indicates a less pronounced decrease in the STIR. This will lead to discussions about tissue characterization and may be of diagnostic value.
The subcutis (subcutaneous fatty tissue) is normally very light on T1. Here, there is an inflammatory oedematous infiltration of the subcutis; therefore, the structure is uneven: it has light-coloured nodules separated by a dark network. The fluid surrounding the fat lobules is now dark, and the fat lobules themselves are light.
As already mentioned, you should see a decrease in brightness in the distal tibia area in this T1. This is caused by a displacement of fat marrow by fluid in the area of the stress fracture. The effect is not so clear, maybe the “center” (the middle gray value) is too low. The decreased brightness still appears too light, which makes diagnosis difficult.
The fat signal (typical for T1) is particularly weakened along an oblique line. This is how the black line appears.
4c T1 fat saturation and after intravenous contrast administration
The third image 4 c for this case is related to b because it is also T1-weighted, but it still looks completely different; it also has a (seeming) similarity to a, despite a completely different acquisition mechanism (a spin-echo sequence instead of inversion recovery). “c” is T1 after intravenous contrast administration (KM).
Only a T1 image can detect the contrast agent. Unfortunately, not only is the contrast agent bright, but so is the fatty tissue, which interferes with detection. However, there is a very important tool that improves the information: fat saturation. All fat is dark instead of bright. Perhaps the most typical finding in a T1 image is that bright fat is reversed. Free fluid is and will remain dark on the T1 image anyway. There is only one brightness in the image, the contrast agent. So we have a picture of the contrast distribution in the body: hyperemia (and increased metabolism) is very bright. Most pathologies are characterized by such increased metabolism and can be detected in this way.
In our case, the contrast distribution does not show synovial proliferation, which is typical of arthritis. The pathologic enhancement is found in the distal tibia: an irregular, striped enhancement. Further down, above the ankle, there is an area of unusual bone structure. This would also be very unusual for an inflammatory joint process.
Where the contrast becomes more visible in the bone, there appears to be a “hot” metabolism due to a reparative process. Within this healing zone, there is an oblique, brighter line – apparently the section of an area of increased blood flow activity. The shape and structure do not suggest a tumorous neoplasm (growth) with its destruction of existing normal tissue structures.
It is a classic overload.
The misinterpretation of the temporal relationship between the complaints and the preceding overload is remarkable. It was not recognized that the bone needs time to react (and also to heal). It was not recognized that the overload damage also manifests itself in and on the (adjacent) soft tissues. This also applies to the eight different forms of overload damage described in article 01 (acute or chronic trauma, growing or fully developed bone, healthy or previously damaged bone metabolism; each individual case of disease has these three alternatives, of which only one possibility applies. Thus, there are eight different constellations of “osteoarthritis”).
Case 5:
Enthesopathies are closely related to stress fractures. In the broadest sense, they are “sterile inflammations” of the tendons caused by incorrect loading.
Figure 5 a +b: coronal slices; STIR and “non-fat saturated T1
Figure 5 c: T2* sagittal
The 28-year-old athlete had been training hard for the past five weeks.Slowly increasing pain in the Achilles tendons on both sides of his body eventually became so debilitating that he could only stand on his toes in pain.At the same time as the pain was increasing, he noticed localized swelling of the Achilles tendons on both sides.
Below the STIR image (bottom right) you can see the sequence”; a very normal T1 image, so to speak. The tendon and the water retention are dark and therefore difficult to distinguish. However, the resolution is good and the anatomy is clearly visible. The pathological change in the Achilles tendon is clear.
5c: a gradient echo T2* is shown in sagittal section. This is a commonly used sequence with T2 characteristics: fluid, and therefore almost all pathological tissue, is bright. Fat is moderately bright; less bright than in T2 spin echo; not nearly as signal-intensive as in T1; but certainly, in stark contrast to STIR, which “suppresses” the fat signal.
What are the main differences between T1 and T2? Increased fluid content (applies to almost all pathology) dark in T1 but bright in T2.
What do T1 and T2 have in common? Fat is light. – But much more so in T1. – (What is one of the few substances that behaves exactly like fat (in MR)?
Methemoglobin).
The rule of fat representation does not apply without qualification: different T2 sequences differ in this fat signal. But this widens our options. Sometimes an attenuated fat signal is not desired at all. For example, lymph nodes or bone metastases can show the same brightness as the surrounding “suppressed” fat and thus camouflage themselves. Compared to spin echo T2 and turbo spin echo, gradient echo T2* tends to attenuate the fat signal. The easiest way to do this is to start with a spin echo sequence: this hardly suppresses the fat signal; it has a clearly bright fat signal (T1: very bright fat signal).
This example shows the suitability of this T2* gradient echo sequence. Due to the reduction in fat, the bright signal of the pathological fluid accumulation in the Achilles tendon is very visible. The muscles are quite dark on all T2 sequences anyway. We have already seen this highlighting of pathology with STIR. Does T2* have advantages over STIR? The advantages are not in the tissue differentiation, but in the better detail resolution and the higher measurement speed.
Treatment was conservative with consistent off-loading and physical therapy, including stretching exercises.It took six months for the symptoms to subside.In the meantime, careful exercise was introduced.
Case 6: Acute trauma with infraction of the tibial plateau; (i.e. not chronic but acute overuse damage)
Abb. 6a
Figure 6 a +b; sagittal view; T2*
This is a 43-year-old man who fell from two meters of scaffolding five days ago.
First of all, it is important to note that the x-ray showed no pathological findings. – The patient (five days after the accident) still had severe pain when running, standing, pushing the knee joint, and with valgus stress. A small bloody joint effusion was punctured. Based on the results of this puncture and the persistent symptoms, an MR scan was ordered.
We will not dwell on the description of the MR image, but rather interpret the findings in terms of pathophysiology: extensive bone marrow oedema is seen in the lateral tibial plateau. Two different T2* slices are shown above. There is marked marrow oedema in the dorsal tibial plateau. This oedema is even more evident in the lower (right) image pair. It is a sequence that strongly suppresses the adipose tissue and at the same time highlights the “pathological fluid”: The STIR (bottom pair of images).
With this history, we look for direct signs of fracture: there is no evidence of indentation of the tibial articular surface. The prominent bone marrow oedema in the tibial plateau is crossed by a low signal line in both sequences shown (and in both slice planes). This is probably due to trabecular compression, which reduces the bright signal from the medullary canal. An x-ray scan, such as a computed tomography (CT) scan, could provide evidence to support this hypothesis. Even without CT, the diagnosis is clear from the sum of the sequences and the history:
It is an infraction of the lateral tibial plateau.
Abb. 6b
Figure 6b STIR. This edema is even more evident in a sequence that strongly suppresses adipose tissue while highlighting “pathologic fluid”.
A conservative treatment with partial but constant offloading was decided. – A complex and expensive MR scan makes sense because it shows that this injured region is at risk. A bruise could form here if the load is not reduced. This would probably result in permanent joint damage.
In fact, the patient was symptom-free after a few days. He returned to his office job after four weeks.
The four-month radiograph showed normal findings, i.e., unremarkable bone and soft tissue structure in the tibial plateau and normal joint space width.
Case 7: Overuse damage of the Os Cuboideum
Figure 7 a +b: STIR
An (atypically localized) overload injury was suspected.
Further diagnostics revealed a significantly reduced densitometric value on quantitative CT of the radius. However, normal values were found in the femur and spine. Diagnosis of atypical peripheral osteoporosis.
The overload in the foot skeleton had hit a diseased bone and was therefore particularly effective (and effective in an atypical site).
The symptoms continued to improve, but it took five months before there was complete relief.
Shortly after the relief of symptoms, the patient felt pain in the tarsus on the opposite side after renewed stress. No imaging was performed.
Another three months later she suffered a typical fracture of the right distal radius after a fall. Two years earlier she had fractured three metacarpals in a fall. – It can be assumed that there is a predisposition to acute and chronic trauma. The most common predisposition to such “osseous insufficiency” is osteoporosis.
The patient was treated with calcium and vitamin D. After more than a year, she is doing well. No new overuse injuries or new acute fractures have occurred. There is still no evidence of rheumatological disease. There has never been any evidence of hyperparathyroidism or osteomyelitis
Case 8. Damage to both calcanei (heel bones) of a young person due to overstraining
The 12-year-old patient is a very active soccer player. After a series of very hard training days, he suddenly developed pain in both heels. This forced him to stop his sports activities. An accident was ruled out. – When the pain persisted after several days, even with light exertion, and the x-ray showed only age-typical findings, an MRI was performed.
Figure 8 a – d: MR sagittal of both calcanei
What did the MRI show in our patient? There was extensive bone marrow edema of both calcanei. Both pairs of images are T2* gradient echo sequences. Both heels are shown. (above: left calcaneus; below: right calcaneus)
The pathologic findings show remarkae symmetry: there is extensive marrow edema of the apophyseal nuclei and the metaphysis close to the growth plates.
It is noteworthy that both the apophyseal nucleus, which is already large at this age, and the growth plate and metaphysis close to the growth plate are affected. The normal growth plate also shows increased signal, but this is well above age-physiological levels.
This localization is typical of damage to the growing skeleton. It is most likely a precursor or very early (reversible) form of aseptic necrosis.
With consistent care, this change healed without a trace.
If the changes were progressive, we would expect the apophyseal nucleus to become necrotic and displaced due to growth plate insufficiency. We would also expect the metaphysis, which is also affected, to adapt to this displaced nucleus as part of the reparative process.
Depending on how you look at it, there are different names:
Radiographically, it looks like apophysitis.
Histologically, it can be classified as aseptic necrosis.
In terms of pathogenesis, it is a typical overuse injury in young people.
What is striking about all these cases of “osseous insufficiency” is that they easily fall through the cracks of medical discipline. The surgeon says, “What am I going to do with this patient?
Abb. 8a
Abb. 8b
Abb. 8c
Abb. 8d
Dear readers!
Some of you have come to this page because you are looking for something about the growth plate. The case shown here is a very difficult problem as far as the growth plate is concerned. This case is not suitable as a first introduction. Very briefly: We grow in the growth plates. They separate the core (epiphysis/apophysis) from the shaft (metaphysis). When we stop growing, they fuse together and the joint disappears.
It is easy to imagine that such a zone of a very complicated “bone structure” would be particularly sensitive to, for example, overloading. Such a case is described here.
Another article deals with the growth plate:
Artifacts III, Chapter 7, Figure 05. It can happen that these W. do not close, but remain visible in the Rö. even in adulthood. This was thought to be due to an articular process on the spine.
Würden die Veränderungen fortschreiten, dann erwarten wir, dass der Apophysen-Kern nekrotisch wird und die Wachstumsfuge nicht mehr einen ausrechenden Halt bietet. Der Kern könnte sich dann verschieben. Wir dürfen hoffen, dass das Ganze doch nochmal abheilt, aber dann unter einer Verformung.
Weiterhin wäre zu erwarten, dass sich die ebenfalls betroffene Metaphyse – im Zuge reparativer Vorgängen – an diesen verlagerten Wachstumskern adaptiert. Auch das bedeutet nach der Ausheilung eine Formveränderung. Diese mag für die Funktion mehr oder weniger bedeutsam sein.
Je nach der Betrachtungsweise resultieren verschiedene Benennungen:
Röntgenologisch erwarten wir also das Bild einer Apophysitis.
Histologisch wird diese Erkrankung in die aseptischen Nekrosen einzuordnen sein.
Von der Pathogenese ist es ein typischer Überlastungsschaden im jugendlichen Alter.
Bei allen diesen Fällen von “ossärer Insuffizienz” ist auffällig, dass sie leicht durch das Raster der medizinischen Diszipline fallen. Der Chirurg sagt: “Was soll ich mit diesem Patienten anfangen, der hatte ja gar keinen Unfall.” der Rheumatologe sagt: “Keine Entzündungsparameter!” Fühlt sich der Orthopäde angesprochen?
Allen KollegInnen fallen bei diesen Patienten psychologische Besonderheiten auf. Die Patienten sind getroffen; ihr Krankheitsgefühl ist oft ausgeprägt. Andererseits fehlt auch oft die Einsicht, dass die Therapie möglicherweise einfach ist.
Es sind erfreulicherweise sehr gutartige Erkrankungen. Daher sei den Kasuistiken einen Ausblick in die besondere Psychodynamik angehängt.
9.
Psychodynamic model of overuse injury in key words
Focus on sports trauma in the second half of life.
Overuse injury is the result of a mismatch between stress and resistance. Stress has its own psychodynamics. The factors at work can be divided into endogenous and exogenous factors.
- Endogenous factors
1.1. Personality traits.
- If you suspect damage from overuse, you need to look for evidence of narcissistically disturbed parts of the personality. Characteristic of this is an increased sense of grandeur in imagination and behavior: An exaggerated sense of uniqueness (‘something special’); being consumed by fantasies of power and/or beauty; an increased need for admiration.
- Lack of self-awareness: Due to a lack of body awareness, the body is only felt in borderline situations or when these limits are exceeded. This means that the feelings in the borderline situation, e.g., pain, do not sensitize people to caution and restraint, but rather promote an exaggeration of one’s own performance.
- Lack of ability to deal constructively with conflict. These are sometimes attempted to be removed auto-aggressively by physical abreaction.
1.2. Coping with ageing. Excessive fear of ageing, physical weakness, illness and ultimately fear of death. The defense mechanisms of this fear are: –
- a) -Repression (“I’m still young/young at heart! I don’t mind jogging ten kilometers a day!”)
- b) – Denial (“Getting older doesn’t apply to me! What do they all get out of getting older? Two hours of tennis a day, that’s what I need!)
- c) – Projection
(“Look at that weakling over there! I’m good because everyone around me is so weak and sniveling. When I compare myself to them, I realize how good I am! Anyone who sees me must hurt others!”) 2. Exogenous factors
2.1. In the culturally influenced view of humanity in our society, youth, physical fitness and external beauty are highly valued. This is conveyed and specified in particular by advertising. In order to remain recognizable and to differentiate themselves from the “old”, older people try to conform to this image of physical fitness. Loss of physical and mental performance is not accepted as a natural process; it is excluded and at best tolerated as a pathological exception. Competitive situations often develop in which older people want to compete with younger people (‘… now I’ll show you what I can do’). This leads to overstrain. The new sports that have emerged in the last two decades offer many opportunities to measure and demonstrate performance. These include extreme sports, which provide the necessary “kick”. It is probably also an attempt to repeatedly feel the effects of endorphin release in extreme situations or under extreme physical exertion. Transitions to addictive behavior are fluid. Therapeutic options. The feasibility of therapy depends on insight into the disorder and the ability to introspect. These are often inadequate. The trauma is often perceived as fateful. The self-image does not allow insight into one’s own wrongdoing. The trauma appears to the patient as an external misfortune. The patient has no idea that he or she could be the cause. There is a lack of personal responsibility for the trauma and the causes are projected outwards.
With such a lack of insight into the disorder, there are still various therapeutic options: The suggestive effect of medication. (“As long as you have this bone marrow oedema, a break from training is essential to prevent further damage! The “bone bruise” must speak instead of weak introspection). Other therapeutic options include the use of behavioral change interventions: – Addressing the narcissistic parts of the personality to reduce the need for admiration. (“You don’t have to be so involved.”) – Learning from a model. Relativization and modification of the personality image conveyed by advertising (“You know how I do sports, I do it this way and that way. No one will give me anything if I destroy myself.
If there is sufficient motivation for therapy and insight into the disorder: Deep psychological approach to dealing with primary family causes, e.g., awareness of lack of parental approval or attention, questioning the link between approval and certain achievements. Acceptance only for being “better” than others, etc.
A body therapy-oriented approach to therapy through “gentle therapy methods” such as body awareness training, body relaxation techniques (muscle relaxation according to Jacobsen, autogenic training according to Schultz). Our introductory and continuing education article ends here. If you have any suggestions, please let us know. Email is at the very end.
If you have any suggestions or questions, please contact us:
Schmittbuxbaum(at)gmail.com or wghschmitt(at)gmx.de
Another article on the subject of “Osseous Insufficiency” is the one before, 01.
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