Internal derangement of the knee is caused by an intraarticular tissue interposed between two bone structures. In order to reach an accurate diagnosis, can modern imaging modalities really replace the ”common sense” of clinical reasoning?
According to Cyriax’s classification, internal derangement of the knee is caused by an intra- articular tissue interposed between two bone structures, typically a meniscus fracture or a loose body (cartilaginous, bony/ cartilaginous bodies or a meniscus fragment). In both cases, the patient will report an unexpected and painful lock, immediately followed by functional impairment, perceived unsteadiness and pain upon joint loading.
Objavljamo še drugi del članka našega kolega ETGOM predavatelja iz Italije, Alessandro Marzagalli, Pth, ki obravnava eno ključnih tem OM, t.j. notranja motnja v kolenu.
V prvem delu smo se sprehodili po časovni osi in prišli do slednjega sklepa: Looking is not a substitute for thinking (klikni za branje). Sedaj se konkretno lotimo notranje motnje in še enkrat poudarimo, da v klinični OM na prvem mestu nikakor ni slikovna diagnostika, temveč klinične veščine preiskovanca. Vabljeni k branju –
Upon inspection, the knee will feel locally swollen and warm. Upon functional examination, a locked movement will be identified, featuring a typical end-feel which varies depending on the root cause: a “springy block” feel on subluxation of the meniscus, and a “soft” feel on loose bodies.
Shifting pain is a shifting lesion
A pain “shifting from one side of the knee to another” reveals “a moving injury”: if acknowledged, this will be a clear symptom of the presence of a tiny loose body.
Patients suffering from early gonarthrosis may experience tiny fragments of cartilage detaching from their matrix, thus forming a tiny intra-articular loose body, sometimes small enough to remain undetected by a radiography, CT scan or magnetic resonance imaging.
Misdiagnosed arthritis attack
The clinical picture of pain and functional inability, along with a functional examination limited to a mere – and often painful- palpation procedure on the joint space, may lead a superficial examiner to misinterpret the internal derangement and label it as an arthrosis/arthritis attack. The usually prescribed radiography would not reveal such diagnostic error.
Defining a clear clinical pattern
Cyriax introduced the concepts of end-feel and capsular pattern, which helped set a clear, unambiguous clinical picture of arthrosis and arthritis as opposed to an internal derangement of the knee caused by a loose body (see Table).
The examples above lead to define one of the key points in the present diagnostic system: Diagnosis is not obtained by means of a single reading of the results of an individual test, but only after using such results together with additional elements in the patient’s medical history as well as in previous/ subsequent inspections and a functional examination, all of which make up the so-called clinical picture.
Not only did Cyriax create a clinical diagnostic system: during those years, he also developed effective treatment techniques such as: articular and vertebral manipulation procedures, deep friction transverse massage and infiltrations.
Finding a treatment
Hence, in the event of internal derangement of the knee, once the root of the issue and the type of patient have been identified (e.g. a cartilaginous loose body in an adult showing early stages of arthrosis), then the goal was to find a technique that could guarantee a working conservative treatment. A technique which could allow the practitioner to move the loose body to a different joint zone where articular movement would not be compromised or cause pain: an area defined by Cyriax as “silent zone”.
In order to reach the defined objective, Cyriax developed four different loose body manipulation techniques. Manual therapy was at its earliest stages; however, the manipulation techniques devised by Cyriax to treat internal derangement have not been superseded as of today (10).
Imaging modalities vs. clinical reasoning
Nearly 50 years have passed since, during which medicine and surgery, helped by modern technology, have witnessed a series of major revolutions (11). Nevertheless, as our everyday experience as healthcare professionals along with many different studies show, when it comes to run the diagnostic process of an internal derangement of the knee, MRI does not represent a better method than clinical assessment does; similarly, arthroscopy seems not to be the only solution in order to reach an accurate diagnosis (12,13,14,15).
Fast-track medicine? – we can do better!
Conversely, over-reliance of examiners on imaging diagnosis has led many of them to limit the clinical examination procedure to a fast and incomplete medical history check-up, followed by a functional examination consisting in a rushed palpation of the affected structures. This widely spread M.O. does not allow examiners to reach an accurate diagnosis; instead, an unspecific diagnosis is often formulated (“knee pain”, “arthrosis attack”) or, alternatively, imaging diagnosis is used as the sole source of the diagnostic outcome subject to the risk of such images being wrongly interpreted. Performing a full clinical assessment allows the examiner to evaluate the radio-holographic medical report as well.
The consequences of an incorrect diagnosis might lead to either an unnecessary surgery procedure or an unspecific, ineffective conservative therapy.
‘The right’ clinical approach
The origins of orthopaedic medicine date back a long time ago: it was built on clinical practice, observation skills and applied anatomy studies. As of today, modern technology has not led orthopaedic medicine to successfully replicate the revolutions observed in other areas in medicine. It is still unknown whether this will ever happen, particularly as far as diagnostic methodology is concerned.
Therefore, putting back the art of clinical assessment at the centre of the diagnostic process becomes a matter of key importance, given that the visual identification of an injury is not always possible; and, in any case, even when it is possible, it can never replace the clinical reasoning of a skilled examiner.
Sponzorske ikone iz flaticon.com
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