When is knee arthroscopy the ideal knee replacement procedure?
The knee joint constitutes an anatomical area in which arthroscopic surgery has the greatest potential to treat its injuries.
Knee arthroscopy is a bloodless surgical technique whereby we diagnose or even heal the knee joint.
This is possible by using an endoscope, consisting of a flexible tube containing optical fibers with a camera on its tip. The distal end of the tube is connected to the camera and the other end to a monitor through which the surgeon examines the joint. Below the monitor there is a tower of machines (serum pump, diathermy, shaver, video etc.) that technically support the surgeon.
The camera’s entrance requires an incision at the joint of approximately 3-4 mm, which usually does not even need to be stitched at the end of the arthroscopy. Arthroscopy offers us the ability to perform multiple operations depending on the existing injury. In this way, we avoid extensive incisions, there is less pain and recovery is immediate and quick.
Arthroscopy is usually performed without hospital admission for the patient. The type of anesthesia varies depending on the severity of the injury, the general condition and the age of the patient. The anesthesiologist has the choice among general, epidural, regional or even local anesthesia. Usually, we have at least 2 entry gates with 4-5 mm incisions through which arthroscopic interventions are performed. One of them is for the camera and the other for the tools through which corrective and therapeutic actions are performed. At the end of the procedure, sterile strips are placed on the entrance gates and the knee is bandaged.
Knee injuries that can be treated with arthroscopic surgery are:
- Meniscus rupture
- Anterior cruciate ligament rupture
- Posterior cruciate ligament rupture
- Removal of intra-articular loose bodies
- Repair of articular cartilage defects
- Chondrocyte transplantation in cases of articular cartilage damage
- Patellar instability
- Flushing in cases of bacterial arthritis
- Articular cartilage lesions
The articular cartilage covers articular surfaces and constitutes a smooth and glossy structure. The movement of the joints is due to the special properties of the cartilage such as the extremely low friction index and the ability to properly distribute the loads it receives.
The articular cartilage consists of chondrocytes which produce large amounts of Type-II collagen, which are found in the environment with proteoglycans and elastin fibers. The type of cartilage encountered in the human body is of three types and this is determined by the proportion of the aforementioned components.
The cartilage contains no blood vessels and the nutrition of the chondrocytes is performed through the diffusion of nutrients in the joint.
Its regenerative capacity in relation to other tissues is extremely low.
Traumatic knee injuries
Arthritic cartilage damage in the population is the result of heavy loads that are exerted on an acute or chronic basis in the joint and are mainly associated with sports of intense physical activity. These injuries have a low healing potential and the remaining cartilage gap in the joint triggers symptoms of pain, edema as well as movement inhibition and usually results in the person being withdrawn from physical activity.
If the cartilage damage is left untreated it will lead to chronic degeneration of the joint – premature osteoarthritis – and development of dysfunction.
Many surgical techniques have recently been developed and refined to treat cartilage damage which provides an important solution to the smooth development and progress of the patient’s health.
Patients with localized cartilage damage usually report pain in the problematic area. Physical activity can aggravate the pain and even swell the affected joint.
During physical examination, intra-articular fluid collection can be observed as well as an increase in temperature due to the inflammatory process.
The range of motion of the joint can be quite normal especially in the early stages of the condition. Inhibition of movement and joint involvement may occur if the cartilage is detached and located as a loose body within the joint.
An X-ray of the joint is the first examination. The lower extremities are depicted with the patient in an upright position so that the weight of the body can reveal the anatomical and mechanical axis of the lower extremity.
Magnetic resonance imaging is the method of choice for articular cartilage lesions especially when the simple radiological examination is normal. This examination assesses the extent and depth of the injury, factors that will determine the choice of therapeutic method.
Patients with acute traumatic cartilage damage should be treated immediately. In most cases there is co-morbidity with joint ligament defects which should be included in the recovery protocol.
Patients with chronic or degenerative cartilage damage are initially treated conservatively for at least 12 weeks. Treatment involves altering the patient’s activities by restricting them, physiotherapy, medication (anti-inflammatory drugs, articular cartilage protection drugs, intra-articular hyaluronic acid injections).
Recent advances in the conservative treatment of articular cartilage damage are injections with autologous biological healing agents.
If conservative treatment does not work then surgery is the ultimate solution.
Surgical treatment for knee cartilage damage can be performed arthroscopically or even with “open” surgery.
Debridement of the articular cartilage lesions and trepanning: This method is now performed through arthroscopy and is a minimally invasive procedure. By using this method the physician can remove the cartilage lesions, detect the extent of damage and classify it. In the case where the damage is of 3rd & 4th degree then trepanning of the subchondral bone shall follow.
Chondrocyte transplantation: the procedure is performed arthroscopically with an initial arthroscopy, during which the cartilage is cleaned, delimited and chondrocytes are cultured for re-placement with a second arthroscopy after approximately 20 days.
Bone islet transplantation: the procedure is performed with a small knee incision during which bone cylinders are obtained through the joint from non-loaded surfaces. They are then mounted on the cartilage lesion with the dipping method.
Rupture of the posterior cruciate ligament
The posterior cruciate ligament (PCL) is a very strong knee ligament that controls the posterior movement of the tibia towards the thigh.
The PCL rupture occurs in serious injuries, usually traffic accidents, but also during injuries in sports activities. Fortunately the rapture of PCL is quite rare.
The rupture of the PCL can be a single injury or co-exist with other injuries (usually the so-called posterior medial or posterior lateral rupture).
The diagnosis of PCL is based on patient history and clinical examination. This is confirmed by simple radiography under stress. Magnetic radiography is not the method of choice in the diagnosis of rupture especially in chronic ruptures, since it has very low reliability.
The principles of treatment are based on the degree of knee instability, the patient’s requirements and the coexistence or not of other injuries.
Conservative treatment is applied to single ruptures without major posterior displacement and involves the use of special splints and intense physiotherapy to strengthen the muscles.
Surgical – arthroscopic treatment is performed in cases of single ruptures when the posterior displacement is significant, usually more than 10 mm, as well as combined injuries. Reconstruction of the PCL is performed with a tendon graft – as in the ACL rupture. Other injuries should also be repaired in combined ruptures.
Knee meniscus rupture is one of the most common injuries to athletes but not exclusively to them. Menisci are fibrous resistant structures that play an important role in the biomechanics of the knee joint. They function as a mechanical ligament that allows for better distribution of loads on the articular surfaces of the thigh and tibia; they absorb the vibrations exerted on them and further contribute to the stability of the knee. 60% of the articular loads pass through the menisci.
The knee meniscus is prone to injuries, as well as degenerative processes. The causes that can lead to meniscus rupture are a) extreme movements such as knee rotations with the foot fixed; b) too much flexion in the joint can result in minor or major ruptures; c) immediate injury
The patient may develop:
- mild to severe pain immediately which may subside within days for minor ruptures
- knee edema which is usually observed after 12-24 hours
- involvement of the joint in bending position in cases of major rupture
- a feeling of instability in the joint
- loss of full range of motion
An injured meniscus is essentially an intra-articular loose body that if not treated timely will cause damage to the articular cartilage, i.e. premature osteoarthritis.
After the injury, any activity should be stopped by placing ice around the affected joint.
A visit to an Orthopedic Traumatologist should be programmed as soon as possible so that the clinical examination, as well as the laboratory examination (X-ray, magnetic resonance imaging), can assess the type of injury and determine the recovery protocol.
The type of rupture, the size and the area of the meniscus rupture determine the recovery protocol.
The outer third of the meniscus is rich in blood vessels, which means a greater healing potential (arthroscopic suture of the meniscus). The longitudinal rupture is a typical example.
The two central thirds of the meniscus do not have blood vessels and have no healing potential. These parts cannot be stapled and are usually removed.
If the rupture of the meniscus is very small and there is a clear amelioration of symptoms (pain, edema) then conservative treatment is preferred, which includes:
- Ice therapy for 10 minutes several times a day
- Physiotherapy that aims to strengthen the knee muscles and restore full range of motion
- Anti-inflammatory medication if there is a special reason
- Intra-articular injections of autologous biological healing agents
In previous years until today the partial or subtotal meniscectomy was the only solution. However, removing part of the meniscus is essentially the removal of an important factor in protecting the articular cartilage causing premature degeneration for two reasons:
- large focal forces are developed between the femoral and tibial cartilage at the meniscus deficit site, and
- there is greater and paradoxical movement of bones
The evolution of synthetic implant biotechnology, as well as the development of arthroscopic techniques and tools, has offered today the opportunity to orthopedic surgeons to perform meniscal (synthetic or allograft) transplants and to restore the meniscal deficiency, thus, avoiding premature wear and development of osteoarthritis.
Meniscus ruptures are treated:
- by stitching and maintaining the loose part (in case the part is in good condition), where possible and this is the ideal solution and treatment,
- partial or subtotal meniscectomy, i.e. removal of the loose part and smoothening of the remaining rim.
- transplantation of meniscus by a cadaveric donor (allograft)
- synthetic meniscus transplant. Synthetic meniscus is the latest development in biotechnology and orthopedic surgery on Sports Injuries worldwide and is essentially the scaffold on which the new meniscus of the patient will develop.
Arthroscopic meniscectomy is indicated for patients with meniscus rupture and knee pain as well as mechanical symptoms such as movement inhibition and instability. Initially, an assessment of whether the meniscus can be stitched is required. Several times, due to the nature of the rupture the stitching cannot take place. The loose segment is carefully removed and the remaining part is smoothened to create a normal articular substrate.
In many cases meniscus stitching is the ideal solution for the patient, allowing healing and virtually permanent healing.
The development of arthroscopic techniques and materials nowadays allow the Orthopedic Surgeon to suture the meniscus in various ways depending on the type of rupture and the specific anatomical region.
MENISCUS TRANSPLANTATION (ALLOGRAFT)
Meniscus transplantation is a specialized surgery performed worldwide in specialized centers. The transplant is taken by a cadaveric donor and after being appropriately processed and tested it can be transplanted to a patient with previous subtotal removal of his own meniscus.
The criteria for meniscus transplantation include:
- persistent pain during movement of the knee
- loss of more than half of the meniscus due to previous arthroscopic meniscectomy
- inability to stitch the meniscus due to its extensive degeneration
- the articular cartilage of the joint has not been severely affected (established osteoarthritis is a contraindication for transplantation)
- active patient under 55 years of age
- patient of normal body weight
Proper alignment of the leg as well as the integrity of the knee ligaments are prerequisites for successful surgery. In case of multiple injuries e.g. anterior cruciate ligament rupture, plastic surgery is performed at the same time.
The clinical examination of the patient to be performed by the Orthopedist, the radiological examination as well as the assessment of the joint with magnetic resonance imaging will determine the therapeutic plan.
The purpose of meniscus transplantation is to relieve the patient of pain and to provide protection against the biomechanical consequences of meniscus deficiency (premature osteoarthritis).
TRANSPLANTATION OF SYNTHETIC MENISCUS
After years of research and the collaboration of leading experts, the synthetic meniscus scaffold was created, which constitutes an innovation in knee surgery. The synthetic meniscus consists of a synthetic biodegradable polymer that, with its special cellular arrangement, allows blood to flow through it providing sites for the growth of new cells and creating conditions for a healing process and the creation of new meniscal tissue.
After removing the damaged part of the meniscus, the synthetic scaffold is positioned and sutured with special techniques. Over time, new tissue grows through the scaffold, gradually replacing it. The scaffold is absorbed by the body and in its place a new meniscus is developed.
The advantages of this process are:
- normal range of motion of the joint
- movement of the joint without pain
- prevention of early osteoarthritis
Clinical studies in humans have shown an improvement in their quality of life as well as early return to pre-injury knee status.
Anterior cruciate ligament rupture
The rupture of the anterior cruciate ligament is a major sports injury. The ligament is a strong bundle of intra-articular connective tissue fibers that adheres between the thigh and the tibia. The anterior cruciate ligament is one of the most important knee ligaments. It offers great knee stability.
The anterior cruciate ligament prevents and stabilizes movements such as excessive knee flexion, excessive knee extension and anterior tibial displacement relative to the thigh. When the above movements are made with great force and to such an extent that it exceeds the forces of the anterior cruciate ligament, a rupture occurs. This condition is known as rupture of the anterior cruciate ligament and varies from a small distension of its fibers resulting in mild discomfort to its total rupture resulting in severe pain and impotence. The rupture of the anterior cruciate ligament is classified as follows:
Grade 1: A small number of fibers in the joint are ruptured causing mild discomfort, but full activity is allowed
Grade 2: A significant number of fibers in the ligament are ruptured and as a result activities are partially restricted
Grade 3: All fibers of the joint are ruptured resulting in knee instability and a great loss of functionality. Other knee structures such as meniscus, lateral joints and cartilage are usually injured. In this case, surgical repair is necessary.
Causes of anterior cruciate ligament rupture
Rupture occurs during activities that load the joint. This usually happens during sudden movement, though sometimes it may occur due to repetitive loads exerted on the joint.
There are three main movements that charge the anterior cruciate ligament:
- Knee flexion
- Knee extension
- Anterior displacement of the tibia relative to the thigh
When one of the above movements occurs or any combination of them and the load exerted on the joint is greater than that it can bear, then we have a rupture. Rotational injury is the most common mechanism of rupture of the anterior cruciate ligament.
Rupture of the anterior cruciate ligament is often in contact sports (e.g. football, basketball) or in sports where sudden changes of course (e.g. skiing) are required. The most common injury mechanism is rotation of the femoral bone on the tibia when the weight of the whole body falls on one leg (e.g. during landing). Another mechanism of injury to the joint is when an external force causes the knee to bend in the wrong direction (e.g. when a player falls forcefully on the lateral side of the knee)
Symptoms of anterior cruciate ligament rupture
Patients with anterior cruciate ligament rupture usually hear a characteristic “crack” at the time of injury. In mild cases the activity may be continued and the pain, edema and stiffness may appear or deteriorate after the end of activity or in the next morning. Often the pain is experienced by the patient deep in the knee and the rupture is difficult to be detected. In cases of total rupture there is severe pain, although sometimes it soon recedes. Patients also experience a feeling that the knee “comes out of its place” and then “it comes back in”. In the event of a total rupture, it is impossible to continue any activity due to severe pain and instability. After the injury it is very difficult for the patient to charge the leg with weight.
Diagnosis of anterior cruciate ligament rupture
The medical history and description of the mechanism of injury as well as a detailed clinical evaluation are sufficient to guide the treating physician in the diagnosis of the anterior cruciate ligament rupture.
Magnetic resonance imaging of the joint is necessary to document the disease and the comorbidity of the injury.
Conservative treatment of anterior cruciate ligament rupture
Most patients with first- or second-degree rupture recover with the appropriate recovery program, which includes discharge of the joint initially, and then progressive loading, strengthening physiotherapy sessions, and balance exercises with concurrent medication.
In a total rupture of the anterior cruciate ligament where no surgical repair is performed, there is a strong likelihood that patients will suffer from instability which, after 10 years of documented studies, results in post-traumatic osteoarthritis.
Surgical reconstruction of the anterior cruciate ligament ruptures
Surgical intervention is required in patients with total rupture of the anterior cruciate ligament, in order to obtain maximal functionality. It is now performed with arthroscopic intervention and most often an autologous graft is used (in special cases a synthetic graft or an allograft may be used). The patient undergoing anterior cruciate ligament transplantation remains in the hospital for a total of 24 hours and is then discharged with a knee splint and crutches. Then comes the recovery period which lasts 6 to 12 weeks where the patient returns to previous activities or sports.