An overview of the conditions affecting the Knee, each with information on how they develop, on diagnosis and on treatment. These texts do not replace a medical consultation — in the case of symptoms, we will determine the individually appropriate treatment together.
Knee pain is probably one of the most common reasons for consulting an orthopaedic and trauma surgeon. Before any conservative or surgical treatment, the cause of the complaints leading to the consultation must be identified. The urgency of the assessment depends first on the extent of the symptoms and not least on the presumed cause (accident/trauma or wear/degenerative).
Surgery — yes or no?
In my view, a surgical procedure can be avoided, or at least postponed, for a large number of knee problems. Particularly so-called anterior knee pain, formerly also referred to as chondropathia patellae, usually requires no surgical treatment. For degenerative meniscus tears, too, the trend in recent times has moved away from surgery. This applies in particular when there are no mechanical irritations or entrapments and an already beginning wear of the knee joint explains the symptom picture better than the presumed meniscus damage would. If, however, surgery in the form of a knee arthroscopy to treat a meniscus or cruciate ligament tear, or a joint replacement (total knee replacement or partial replacement), is necessary, I will be glad to advise you at my practice.
Condition 02
Meniscus Injuries
Definition
Within the knee joint there are two crescent-shaped menisci, one each in the inner and outer joint space. Their task is, on the one hand, to compensate for the imprecise fit of the joint surfaces of the thigh bone (femur) and shin bone (tibia) and, on the other, to function as shock absorbers. The latter results from the build-up of the meniscus from fibrous cartilage. The meniscus is supplied with blood vessels only at its base, which explains why the inner parts of the meniscus in particular cannot heal.
Meniscus injuries are among the most common sports injuries, with the inner meniscus affected more often than the outer meniscus. The inner meniscus is fused with the inner collateral ligament and is therefore restricted in its mobility, which makes it more susceptible to injury. Most injuries arise due to pre-existing damage in the meniscus tissue and, less often, as a result of trauma. Direct traumatic meniscus tears, by contrast, occur above all in so-called “stop and go” sports such as tennis and football, but also in skiing.
Diagnosis
The diagnosis of a meniscus injury is usually made clinically. The literature describes a large number of tests for examining both the inner and the outer meniscus. As a rule, combined movements are carried out in order to test the different parts of the meniscus. In terms of imaging, MRI is the method of choice for visualising the internal structures of the knee joint, including the menisci.
Treatment
Depending on the type of tear or injury, there are different surgical methods and forms of treatment. Tears — particularly those that lead to mechanical irritation of the knee joint (effusion and entrapment with consequent restriction of extension) — should be treated surgically. In the case of tears close to the base in young patients, a reconstruction by means of a meniscus repair can be attempted, despite the poor blood supply of the meniscus. For all other tear patterns, only the removal of the damaged meniscus (a so-called partial meniscectomy) remains. In the case of purely degenerative tears without mechanical irritation, and with an already beginning osteoarthritis, meniscus surgery alone does not make sense.
As their name suggests, the cruciate ligaments run crosswise through the interior of the knee joint. The anterior cruciate ligament (ACL) runs from the joint-facing outer side of the thigh bone to the inner side of the so-called intercondylar area of the shin bone. The posterior cruciate ligament (PCL) runs in the opposite direction, from the inner side of the thigh bone to the middle of the shin bone, but behind the ACL. A tear of the cruciate ligament usually leads to a marked instability of the knee joint. This is often noticed by patients as the leg “giving way”.
The anterior cruciate ligament is most frequently injured in sports accidents (skiing, football, handball, basketball, etc.). This usually involves a combined movement trauma — above all flexion and external rotation of the knee joint with a simultaneous knock-knee (valgus) position. These traumas not infrequently also lead to so-called combination injuries, such as the “unhappy triad” (a tear of the medial collateral ligament, the medial meniscus and the ACL). The rarer injury of the posterior cruciate ligament usually occurs in impact trauma while seated in a car (the so-called dashboard injury), or through pressure on the lower leg with a backward-directed force while the knee is bent. In contrast to the ACL, the PCL has a potential to heal, which is why conservative treatment with a brace is possible in appropriate cases.
Diagnosis
The diagnosis is based first on the clinical examination. Here, a displacement of the lower leg relative to the thigh, forwards and backwards, is carried out. With this displacement, also called “translation”, the distance by which the lower leg can be displaced relative to the thigh is assessed. The examination is always carried out in comparison with the healthy side. If an abnormal forward displacement of the shin bone is found compared with the healthy knee (a so-called positive anterior drawer), this is an indication of an injury of the ACL. An increased backward translation indicates an injury of the PCL. With a fresh injury, a knee joint effusion, caused by bleeding into the joint, is regularly found.
As imaging methods, X-rays of the knee joint in two planes are routinely arranged, which can also capture any accompanying bony injuries such as fractures of the tibial head. The classic diagnostic method for assessing the capsule-ligament apparatus is magnetic resonance imaging (MRI).
Treatment
Surgery or conservative? Surgery is not always necessary in cases of a cruciate ligament tear. The decision as to whether and how to operate should always be made jointly by physician and patient, with regard to age, sporting activity and the subjective feeling of instability. If the person affected is not excessively active in sport and does not feel restricted in everyday life by the cruciate ligament tear, a surgical procedure on the knee is usually not necessary. In this case, targeted muscle strengthening (quadriceps and hamstrings) is carried out to compensate for the instability.
For very young and athletically active people, as well as for patients in whom no stability can be achieved despite conservative therapy with sufficient muscle strengthening, a cruciate ligament reconstruction is advisable. This is nowadays carried out arthroscopically. For the replacement of the cruciate ligament, different grafts are available, with a so-called semitendinosus-gracilis graft used in most cases in Europe. As alternatives, a patellar tendon reconstruction (the so-called bone-tendon-bone technique) and the use of the quadriceps tendon are also available.
Postoperative rehabilitation begins immediately after surgery and lasts, depending on the technique, four to six weeks. I generally recommend partial weight-bearing for 4 weeks. After that, weight-bearing with the full body weight is possible. Competitive sport at a professional level should be avoided in the first six to nine months. Everyday loading after cruciate ligament surgery is, however, possible again comparatively quickly.
The inner (medial) collateral ligament (MCL) stabilises the knee joint on its inner side. With injuries of the medial capsule-ligament apparatus, tenderness on pressure and swelling occur along the course of the ligament. The inner ligament (MCL) divides broadly into a superficial and a deep part. The deep part is connected to the inner meniscus, which frequently leads to accompanying injuries of this structure.
Diagnosis (inner ligament)
If, with the knee slightly bent, an increased opening of the joint is possible (especially at a moderate flexion of about 25°–35°), a collateral ligament injury is suspected. In addition to the clinical examination, an X-ray and, if necessary, an MRI should always be arranged. Both clinically and radiologically, a three-part grading has become established: a grade 1 lesion describes a strain of the ligament, a grade 2 lesion a partial tear, and a grade 3 lesion a complete tear with a break in the continuity of the ligament.
Treatment (inner ligament)
For grade 1 and 2 ligament injuries, early-functional therapy is advisable: immobilisation with the aid of a knee immobilisation brace with a lockable hinge joint, cooling and pain medication. A surgical procedure is necessary only for larger bony avulsions of the collateral ligament or for injuries of several ligaments (so-called multidirectional instability). For combined ligament injuries — in particular in combination with cruciate ligament tears — usually only the reconstruction of the anterior cruciate ligament is necessary.
Lateral capsule-ligament injuries
Injuries of the lateral collateral ligament (LCL) occur less frequently compared with injuries of the inner ligament. In the case of an injury of the outer ligament, injuries of the posterior, outer capsule (the so-called posterolateral corner) almost always also occur. To make matters worse, owing to its close anatomical relationship, injuries of the outer capsule-ligament apparatus frequently also involve accompanying injuries of the peroneal nerve. With a purely lateral injury, conservative treatment by means of immobilisation, cooling and painkillers is usually carried out. For combination injuries — in particular injuries of the posterior corner with persistent instability — more complex reconstructions are necessary.
Condition 05
Patellar Tendinopathy (Jumper's Knee)
What is patellar tendinopathy?
Patellar tendinopathy, as the name suggests, manifests itself through pain in the lower area of the kneecap (patella) — at the transition to the patellar tendon. The kneecap protects the knee joint and, as the largest sesamoid bone of the human body, allows better force transmission of the thigh muscle (the quadriceps femoris). The cause of this condition is primarily overuse — above all with repeated jumping and running movements.
Diagnosis
Initially, pain — especially after more intense strain — is usually the main feature. As the condition progresses, load-related pain and pain at rest can also occur. Locally, tenderness on pressure and on stretching is noticeable. A swelling in the area of the lower pole of the patella may, but need not, be present.
Treatment
As with all overuse, the most important measure is the modification of strain. Nowadays a modification of strain is rather favoured, as immobilisation can lead to restricted movement and structural changes in the tissue. Special taping methods and transverse frictions, as well as targeted physiotherapy, usually lead to a clear relief of pain. As the condition progresses, specific muscle strengthening and stretching of the affected tendons are advisable. Locally, cold applications, quark compresses and, if necessary, the use of pain-relieving and anti-inflammatory medication (NSAIDs) or local infiltration can provide relief. As additional measures, irritation-suppressing electrical applications, salicylate iontophoresis and, if necessary, shock-wave applications (ESWT) can be helpful.
In the case of long-lasting and treatment-resistant pain, an arthroscopy is also conceivable, in which the presumed inflammatory tissue is removed in order to induce healing.
Condition 06
Baker's Cyst (Popliteal Cyst)
What is a Baker's cyst?
The Baker's cyst, also called a popliteal cyst, is a cyst named after a London surgeon, which arises through an increased pressure of joint fluid in the hollow of the knee — in the posterior knee joint capsule. A Baker's cyst is merely a bulging of the joint capsule at the back of the knee joint. They are not always painful and are basically harmless. In adults, internal damage to the knee joint, or another cause of a joint effusion such as rheumatoid arthritis, is the cause of the development of a Baker's cyst.
Diagnosis
A feeling of tension and a usually tender swelling in the hollow of the knee point to a Baker's cyst. The pain is usually not very pronounced and can vary depending on strain. As differential diagnoses, a deep vein thrombosis and — in the case of redness and fever — also erysipelas must be ruled out.
Treatment
Therapeutically, it is the cause and not the symptom that must be addressed. The most common therapy is therefore the elimination of the underlying meniscus damage, or — in the case of rheumatoid arthritis — for example the removal of the inner joint lining (synovectomy). In exceptional cases, a resection of the Baker's cyst via the hollow of the knee may be necessary.
Condition 07
Ahlbäck's Disease
What is Ahlbäck's disease?
If a reduced blood supply to the bone occurs in the thigh close to the knee joint, this leads to its breakdown and death (osteonecrosis, bone infarction). Classically this affects the medial — that is, inner-lying — part of the thigh bone close to the knee joint (the medial femoral condyle). The cause is largely unknown. The changes occur with increased frequency between the ages of 60 and 70, predominantly in women.
Diagnosis
An X-ray image and, above all, magnetic resonance imaging (MRI) are used for the diagnosis. While on the X-ray a density (sclerosis) can be recognised only in the later stages, on MRI it is possible to detect even early forms. Clinically, load-dependent pain is initially the main feature, with pain at rest occurring later as well.
Treatment
In the early stage, pain-relieving and anti-inflammatory medication is administered, and immobilisation/relief of the affected knee joint is prescribed. In addition, either circulation-promoting substances or medication that inhibits bone breakdown (e.g. bisphosphonates) are available. On the surgical side, in addition to a relieving drilling (so-called “core decompression”) and cartilage-bone transplants (the so-called “OATS” technique) as joint-preserving measures, joint replacement (partial or complete) is ultimately also among the options.
Condition 08
Osteochondritis Dissecans (OD)
What is osteochondritis dissecans?
In OD, similarly to Ahlbäck's disease, there is a presumed reduced blood supply of the thigh bone close to the knee joint. As a consequence of this, a death (necrosis) of the cartilage and the bone occurs. The condition typically appears in adolescence, but is frequently diagnosed only later. In the course of the reduced blood supply, a detachment of parts of the cartilage can occur. These then come to lie as so-called loose bodies within the knee joint and can cause irritation effusions and blockages.
Diagnosis
In the early stage, symptoms occur only rarely. Only in the later course of the condition do load-dependent knee pain with recurring effusions occur. In the initial phase (stages I and II), changes are visible only on MRI. With increasing detachment of the cartilage (stages III and IV), the changes also become visible on the X-ray. The method of choice for confirming the diagnosis, after an initial X-ray, is MRI.
Treatment
In the early stage, the knee can be stabilised with the aid of a brace. The joint should also be spared. Jumping and running sports should be avoided. In the case of marked symptoms, surgery can be considered: in stage I a so-called retrograde drilling is carried out; in stage II, depending on the cartilage damage, an antegrade drilling from the joint side is also performed. If parts of the cartilage are already detaching, an attempt is made to reattach the loose bodies by means of special pins. Further options are so-called cylinder transplantations (OATS) or the transplantation of previously harvested and cultured cartilage cells (ACI or MACI).
This refers to a painful irritation of the patellar tendon at its insertion on the front of the shin bone (a so-called apophysitis of the tibial tuberosity). Reduced blood supply, combined with simultaneous overloading of the growing skeleton, is discussed as a cause. This condition occurs above all in boys between the ages of 10 and 14. Clinically, pain and swelling in the area of the patellar tendon insertion are the main features. As a rule, the condition heals without consequences after the completion of growth.
Treatment
Surgery is necessary only in exceptional cases. A break from sport, or a modification of strain, and physical measures, as well as physiotherapy and transverse frictions, are helpful. In addition, the oral use of painkillers and — in difficult cases — temporary immobilisation with the aid of a knee brace may become necessary.
Condition 10
Patellar Dislocation
What is a patellar dislocation?
A dislocation of the kneecap from its gliding bed on the thigh bone (femur) is called a patellar dislocation. This dislocation virtually always occurs outwards. Girls under the age of 20 are most frequently affected. Various causes can lead to it: a malformation (dysplasia) of the gliding bed or of the patella, an over-extensible knee due to a general looseness of the ligaments, or a tear of the inner suspension apparatus of the kneecap (the medial patellofemoral ligament, MPFL).
Diagnosis
Diagnostics are carried out by means of X-ray and magnetic resonance imaging (MRI). On the X-ray, a so-called patellar skyline view is taken at 30, 60 and 90 degrees of flexion. In this, an outward deviation of the kneecap — a so-called lateralisation tendency — and bony changes in the gliding bed of the kneecap can be seen.
What we recommend
After a first dislocation without accompanying cartilage injuries, immobilisation in a knee brace or a plaster cast for four to six weeks may be sufficient. At the same time, intensive muscle strengthening — above all of the front thigh muscle (the quadriceps) — should also be carried out.
Only if these conservative therapies are not sufficient is surgery necessary. The operation now most frequently carried out is the so-called MPFL reconstruction, in which a tendon close to the knee is looped through the kneecap and fixed on the inner side of the thigh. As bony procedures, a transfer of the patellar tendon insertion inwards or an improvement of the bony gliding groove (trochleoplasty) are available.
So-called chondropathia or chondromalacia patellae is a very common condition, especially in adolescents. Clinically, sometimes severe pain in the kneecap area — particularly when walking downhill — is the main feature. As the pain manifests itself rather diffusely on the front of the knee joint, this pain pattern is nowadays increasingly described as anterior knee pain. The cause of this pain pattern remains unclear.
Diagnosis
Clinically, the diagnosis is supported by the so-called Zohlen test. The diagnosis is based primarily on the clinical picture and on the exclusion of other diseases of the knee joint. An MRI is in most cases not strictly necessary, but can be carried out in the case of persistent, treatment-resistant pain.
Treatment
Treatment is usually conservative, with active and passive therapeutic exercises. The main focus is on strengthening the quadriceps femoris through eccentric loading, together with simultaneous stretching of the muscle. In addition, physical applications such as salicylate iontophoresis, electrotherapy and fango packs can be prescribed. Kinesio taping and transverse frictions have also developed into a good treatment option. Surgical treatment is necessary only very rarely.
The bow-leg or knock-knee malalignment of the leg can occur on one or both sides. Up to the age of 2, a bow-leg position is physiological. As development continues, an increasing valgus alignment occurs up to about the age of 7. From the age of 8, an approximately straight leg axis should be present. Depending on the extent of the malalignment, such a condition can be treated.
Diagnosis
During the examination, the entire leg must be examined, in particular the feet, as knock-knees often occur in combination with flat-footedness. It is equally important to examine the hips.
Treatment
In childhood, with minor malalignments, insoles with appropriate correction can be sufficient. In the case of a severe malalignment, a so-called osteotomy, or a closure of the growth plate, can be considered. In adults, the axial malalignment can be eliminated by means of an osteotomy, in order to forestall any premature wear of the knee joint. For a bow-leg, the correction is usually carried out by means of an opening-wedge tibial osteotomy; for a knock-knee, usually a so-called closing-wedge osteotomy on the inner side of the thigh. Full weight-bearing of the leg is, as a rule, possible again after a few weeks.
Following on from coxarthrosis, gonarthrosis describes the wear of the knee joint. Gonarthrosis is the most frequently occurring form of osteoarthritis. In addition to being overweight as one of the most significant risk factors, an axial malalignment (bow-leg or knock-knee) in particular represents a further risk factor. In many patients the so-called patellofemoral joint is also affected.
Symptoms and diagnosis
Typical of the classic wear of the knee joint are, initially, load-dependent pain. This is particularly noticeable during the first steps — referred to as so-called start-up pain. As the condition progresses, restricted movement and pain at rest increasingly occur.
During the clinical examination, larger axial malalignments can be identified. Further signs are tenderness on pressure at the joint space, swelling or warmth and grinding noises. The X-ray images are taken in two planes. If the cartilage condition is still unclear, an MRI can subsequently also be carried out.
Treatment
Initially, local therapy is the priority. Locally decongesting measures such as ice and quark, as well as the use of pain-relieving and anti-inflammatory substances, should be applied in this phase. In the irritation-free phase, a so-called viscosupplementation with hyaluronic acid can be considered. As an alternative, in young people ACP (autologous conditioned plasma) can also be considered. Furthermore, muscle strengthening of the thigh musculature is necessary.
In the case of severely advanced osteoarthritis of the knee joint, artificial knee joint replacement is the treatment of choice. Depending on the degree of severity, different prostheses can be used. If only one section of the joint is affected, a so-called partial replacement (unicondylar replacement) can also be implanted. I will be glad to inform you about the different types of prosthesis, approaches and their advantages and disadvantages at my practice.
In the immediate postoperative phase, the main focus is on pain reduction and decongestion. At the same time, care is taken to restore the ability to bend and straighten the knee as quickly as possible. I generally recommend the use of forearm crutches for 4–6 weeks.
