Meniscal Tears
Knee injuries are extremely common in the population and out of the knee pathologies meniscus tears seem to be the most common. Meniscecetomy was the standard procedure employed in the 90s and early 2000s but unfortunately a high number of people reported joint instability after the procedure and started exhibiting signs of early degeneration in the knee. High rates of reoperation and persisting pain after surgery were some of the factors that called for the need of other non-operative means of treatment. Comprehensive Platelet Rich Plasma with prolotherapy has become extremely popular in the management of these injuries and we honestly feel all meniscal injuries without surgical indications should be subjected to PRP with prolotherapy as the first line option.
Meniscus Anatomy and Function
The menisci are C- shaped fibrocartilage nous structures, with the medial meniscus being slightly more circular than its hemispherical lateral counterpart. Each meniscus has a flat underside to match the smooth top of the tibial surface, and a concave superior shape to provide congruency with the convex femoral condyle. The attachments of the anterior and posterior horns onto the tibia keep the menisci in place.
The menisci are believed to carry out functions like nourishment and lubrication of the articular cartilage, shock absorption and adding stability to the knee joint.
Menisci as a team player in providing Stability to the knee joint
The menisci play a role along with the other ligamentous structures in bringing stability to the knee joint. On the medial aspect, the medial collateral ligament gives a strong connection to the medial meniscus along with the medial tibial and femoral condyles .laterally, the lateral collateral ligament (LCL) attaches to the lateral femoral epicondyle and the head of the fibula. The collateral provide tension and limit motion during extremes of movement. ( full flexion and extension) Several ligaments work together with the menisci to prevent overextension of any motion. The anterior and posterior menisco femoral ligaments form an attachment between the lateral meniscus and the femur and remain taut during complete flexion. The anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) are key to prevent excessive backward or forward motion of the tibia.
Shock Absorption
- The menisci are responsible for shock absorption. This is brought about by distribution of weight equally across the joint and preventing contact wear as the menisci function as efficient spacers between the femur and tibia.
- The menisci are believed to transmit 45-70% of the weight bearing load in a structurally sound knee. The meniscus prevents direct stress at any one point in the knee.
- Proper weight transmission by the menisci helps in offloading other joints as well.
Lubrication and Nutrition
The articular cartilage on the femoral and tibial side is avascular and is dependent on the meniscus to provide lubrication to the knee joint. This is accomplished by the menisci by diffusing synovial fluid across the joint.
Injury
Twisting injury of the knee and injury suffered while getting up from a squatting position are some of the common traumatic insults.
The menisci also undergo age related wear and tear.Meniscal damage can be caused by either trauma or gradual degeneration. Traumatic injury is most often a result of a twisting motion in the knee or the motion of rising from a squatting position, both of which place particular strain and pressure on the meniscus. Tears are the most common form of meniscal injury and are generally classified by appearance into four categories:
- Longitudinal tears- (also referred to as bucket handle tears)- Vertical tear along the long axis of the meniscus usually with displacement of the inner margin.
- Radial tears- extend from medial rim to the lateral rim.
- Horizontal tears- Present along the horizontal axis of the meniscus.
- Oblique tears- full thickness tears extending from the inner margin to the body of the meniscus.
- Complex tears- Combination of two or more tear patterns.
Precarious Blood Supply
The self-preserving capacity of the meniscus is somewhat hampered owing to the fact that a very small portion of the meniscus(10-25%) receives direct blood supply.[6] This area is often referred to as the red zone, and the inner portion of the meniscus which does not receive blood supply is referred to as the white zone . Healing in the white zone is next to impossible owing to its vascularity whereas the red zone has a better chance of healing itself.
Whereas younger people usually suffer from traumatic tears , incidence of degenerative tears increases drastically with age. Moreover these degenerate tears are considerably less likely to heal because of the decreased diffusion of synovial fluid
Symptoms of Meniscal Tears
- Traumatic meniscal injuries might be accompanied with an audible pop at the time of injury.
- Pain is usually the first symptom. As pain might be present from the time of injury itself as in traumatic tears, the onset of pain in degenerative tears is more gradual.
- Swelling and limitation in range of movement might be seen.
- Clicking, popping or locking of the knee joint may be experienced when a flap of medical tissue is caught during movement of the joint.
Signs of Meniscal Tears
- Apley’s Test
- Mc Murray’s test
- Thesaly’s test
Discoid Meniscus Condition
Discoid meniscus is another cause of meniscal tears. A discoid meniscus has an aberrant morphology when compared with the normal meniscus (figure) leading to incongruity. Presenting commonly in the adolescent age group, the lateral meniscus takes up the shape of a disc rather than the usual crescent shaped morphology. Discoid meniscus usually presents with snapping of the knee in extension as the femur slips over a ridge in the meniscus. They tend to go undetected till an individual suffers from an injury and is investigated into.(MRI Imaging)
Imaging
MRI is considered as the gold standard, when it comes to imaging of the meniscus. Still it is not a great idea to depend on MRI alone due to the high number of false positive and false negative patients. One study that brought these issues into the spotlight was performed on college basketball players at Duke University who displayed no clinical symptoms of knee abnormality. Internal irregularities of the knee including cartilage defects, joint effusions, bone marrow enema, and even discoid menisci were found on the MRIs of 75% of subjects, who never displayed any symptoms of meniscal abnormalities.[ Because of the extensive attachment of the meniscus to other structures, an increased signal uptake can very well mimic a meniscal tear.
Limitations of Surgical Repair
The traditional surgical techniques of meniscectomy have come under a lot of scrutiny in the past couple of decades. A considerable number of studies show that although there is some short-term improvement in aspects such as pain control, the long term effects of meniscectomy, meniscal repair, and meniscal allograft transplantation reveal that symptoms, such as pain and instability, will persist for years afterward. The main reason that these and other treatments are ineffective in healing the meniscus can simply be attributed to the fact that, regardless of what is done to structurally repair the meniscus, it is still primarily an avascular cartilaginous structure which cannot heal without a sufficient supply of nutrition.
The takeaway is that surgery does not initiate the regenerative process and sometimes procedures such as meniscectomy can even trigger the degenerative cascade of arthritis. Hence it is our firm belief that regenerative treatment should be considered for most patients with a meniscal pathology.
Comprehensive Platelet Rich Plasma with prolotherapy for Meniscal Pathology Is the first line treatment option advocated at ALLEVIATE
As the platelets reach the injured meniscus, they release important growth factors primarily from the alpha granules. They bring about the healing process by the basic stages of inflammation, fibroblastic proliferation and maturation. We intern are trying to initiate and complete the healing process which has been halted or not been initiated before.
The surrounding structures such as the Collateral ligaments, Cruciate ligaments, joint line, capsular attachments, quadriceps and patellar tendon insertions, vast us medals and the pet anserine are some of the structures that are addressed with comprehensive prolotherapy.
We also supplement hyaluronic acid in our first session as quite often the meniscal damage is associated with early arthritis and compromised lubrication of the joint.
This has to be coupled with a strong and intensive physical rehabilitation protocol. Special attention is netted out for the strengthening of Quadriceps and Hamstrings. Further a Multidisciplinary approach is the fastest way in reaching one’s goals.
References
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- Last RJ. Some anatomical details of the knee joint. J Bone Joint Surg. 1948. 30(4): 683-688
- Bourne RB et al. The effect of medial meniscectomy on strain distribution in the proximal part of the tibia. J Bone Joint Surg Am. 1984. 66-A(9): 1431-1437.
- Messner K et al. The menisci of the knee joint: anatomical and functional characteristics, and a rationale for clinical treatment. J Anat. 1998. 193:161-178
- Arnoczky SP et al. Microvasculature of the human meniscus. Am J Sports Med. 1982. 10(2): 90-95.
- King D. The healing of semilunar cartilages. J Bone Joint Surg Am. 1936. 18(2):333-342.
- Petersen W et al. Age-related blood and lymph supply of the knee menisci. Acta Orthop Scand. 1995. 66(4): 308-312.
- Yaniv M, et al. The discoid meniscus. J Child Orthop. 2007. 1(2): 89-96.
- Smillie IS. The congenital discoid meniscus. J Bone Joint Surg. 1948. 30-B(): 671-682.
- Major NA et al. MR imaging of the knee: findings in asymptomatic collegiate basketball players. AJR. 2002. 179:641-644.
