Meniscus Injury: Pro Level Insights

Knee meniscus injuries are prevalent in both athletic and non-athletic populations, often leading to pain, functional limitations, reduced activity and quality of life. In this blog I am going to give a brief overview of the anatomy, role and function of the meniscus, injury mechanisms, signs and symptoms and give some professional insight into how we would manage an injury to the meniscus.

Anatomy and Function of the Knee and Meniscus:

The knee joint is a complex structure composed of bones, ligaments, tendons, and cartilage, enabling movement and weight-bearing activities. It consists of three main compartments: the medial, lateral, and patellofemoral compartments. Within these compartments, the menisci—two C-shaped fibrocartilaginous structures—serve pivotal roles in load transmission, stability, and shock absorption.

Anatomy of the Meniscus:

The menisci are attached to the surface of your Tibia (shin bone) with the head of the femur (thigh bone) sitting on top of it. They are composed of collagen, proteoglycans, and water. The medial meniscus is more prone to injury due to its anatomical attachment to the joint capsule and medial collateral ligament. They have raised edges and get thinner, sloping down, towards the centre of the knee.

Functions of the Meniscus:

The main function of the menisci is to disperse forces that the knee joint is subjected to everytime we strike the floor during movement, reducing the stress on articular cartilage.

They form a C shaped shallow cup, helping to centralise the head of the femur as it articulates with the tibia. They contribute to joint stability by deepening the articular surface of the tibia, creating a “train track” for the articulating surfaces, along with absorbing force, distributing shock, and protecting the joint from excessive impact during movement.

Mechanisms of Injury:

Traumatic Injuries: Often, these are associated with sports-related activities involving sudden twisting and/or hyperflexion of the knee joint, leading to splits or tears in the meniscus. Direct contact, sudden changes in direction, or rotational forces can all contribute towards this kind of injury, often happening at high velocity or with sudden significant forces. Meniscal tears can range from minor to severe, affecting the inner, outer, or central areas of the meniscus.

Degenerative Injuries: These occur due to normal, age-related changes, where degeneration of the meniscus over years of normal and active living occurs. Small fissures may occur over time, asymptomatic, making it more prone to injury from what can seem like minimal trauma. 

Repetitive Stress Injuries: These are essentially a combination of the two causes above. Long-term repetitive stress, such as those encountered in specific occupations or certain sports, can also contribute to meniscus injuries, combined with normal associated changes as we age. Although we know our tissues like to be compressed and loaded for normal healthy cellular breakdown and repair, other factors such as genetics may also have an impact, some occupations expose us to movements and mechanisms which are menisci can be vulnerable too.

Early Stage Management

Clinical Assessment:

A comprehensive clinical evaluation involving patient history, physical examination, and specific tests aids in identifying meniscus injuries. Special tests such as McMurray's, Apley's, and Thessaly's tests are commonly used to diagnose meniscal pathology. However, these tests all have their limitations and a comprehensive subjective assessment by an experienced clinician should form the basis of assessment and diagnostic decisions.

Imaging:

While clinical assessment is crucial, imaging techniques like magnetic resonance imaging (MRI) can play a specific role in confirming the diagnosis and determining the extent and type of meniscus injury. While this is true, often it is not needed and should be used only when clinically indicated to help form the most efficient management plan.

Conservative Management:

Early-stage management of a meniscus injury should primarily involve conservative strategies. 

These may include:

POLICE Protocol (Protection, Optimal Loading, Ice, Compression, Elevation): These principles aid in reducing pain, inflammation, and swelling as well as protecting the insulted tissue during the early stages.

Pain Management: Non-steroidal anti-inflammatory drugs (NSAIDs) can help manage pain and inflammation, but they shouldn’t be used in the first 5-7 days during the acute inflammatory phase, this is because they block certain cellular functions which are important for early stage healing. As annoying as inflammation can be, unsurprisingly we actually need it for good tissue repair.

Physiotherapy should form the primary basis of all meniscus injury management. It is well understood now that the large majority of meniscus injuries will recover with conservative management. Appropriately loading the musculature surrounding the knee with targeted exercises will play a pivotal role in early rehabilitation. Exercise should focus on not irritating the damaged tissue and most patients will be surprised by what they can do when guided appropriately. 

Surgical Intervention:

In cases where conservative management fails or for severe injuries, surgical intervention like meniscal repair or partial meniscectomy might be necessary. The majority of surgeons will want patients to have undergone at least 8-12 weeks of guided conservative management with a physiotherapist first, not only may this mean someone does not require surgery, but this is good for post-surgical outcomes and often leads to quicker functional recovery times. There are many reasons why people end up having surgery, and more often that not following our favourite sports stars and the media coverage of their injuries and how quickly they get surgery isn’t helpful. The decision for surgery should always be dependant on the individual's case and include an informed discussion with their health care practitioners.

Conclusion

Knee meniscus injuries pose significant challenges for both patients and clinicians. Understanding the intricate details of knee anatomy, the role of the meniscus, injury mechanisms, and early-stage management is fundamental for effective treatment and rehabilitation. As physiotherapists, a thorough grasp of these aspects enables us to design personalised treatment plans, optimise recovery, and help patients regain function and mobility.

References:

Englund, M. (2012). The role of the meniscus in osteoarthritis genesis. Rheumatic Disease Clinics of North America, 38(3), 561-576.

DeHaven, K. E. (1999). Meniscus repair. The American Journal of Sports Medicine, 27(2), 242-250.

Greis, P. E., Bardana, D. D., Holmstrom, M. C., Burks, R. T. (2002). Meniscal injury: I. Basic science and evaluation. Journal of the American Academy of Orthopaedic Surgeons, 10(3), 168-176.

Remember, individual cases may vary, and the information provided is for general understanding and guidance. Always consult with medical professionals for specific diagnoses and treatments.