A meniscal tear is one of the most common sports-related knee injuries in the United States. Traumatic tears in young athletes and middle-aged weekend warriors are usually treated surgically, even though beneficial evidence from clinical trials is lacking and has even shown no difference in outcomes for range of motion, pain, quality of life, and physical performance when compared to sham and physical therapy. Instead, there is evidence that both total and partial-knee meniscectomies are linked to early osteoarthritis. (see research summary below)
Arthroscopic partial meniscectomy
Arthroscopic partial meniscectomy is the most frequently performed orthopedic surgery in the world. Approximately 750,000 are performed each year in the USA, 40% of whom are patients under 45 years old. The concern is that long-term outcomes have shown an increase in developing osteoarthritis compared to non-surgical counterparts (see research summary below).
As far back as 1946, researchers found that the removal of the meniscus had a direct link to the development of early osteoarthritis. Even though the vitality of the meniscus was well-known 80 years ago, surgeons still to this day routinely remove it, but now only partially. Many young athletes had full meniscectomies in the 80’s and early 90’s and 20 years later found themselves requiring a full knee replacement. Surgeons then moved toward arthroscopic partial meniscectomies, a less-invasive procedure, and attempted to maintain as much of the meniscus as possible. For years, arthroscopic knee surgery was shown to have positive early and long-term outcomes. But the research was flawed in that this surgery was rarely compared to sham or conservative care. Only recently has higher level randomly controlled trials compared partial meniscectomy to sham surgery and conservative care/ physical therapy. The long-term outcomes of partial knee meniscectomies were linked to the early development of osteoarthritis.
Shock absorption or protecting the knee from wear and tear is the primary function of the meniscus. When the meniscus is reduced due to surgical resection, the load distribution is thrown off, causing an increased force on the articular cartilage during weight-bearing. This interferes with shock absorption, which can lead to breakdown and eventually leads to osteoarthritis. This is why even partial knee meniscectomies are linked to early osteoarthritis.
The meniscus is fibrous cartilage or a cushion between the upper femur and the lower tibia bone. It is divided into three zones based on the degree of vascularization (blood supply). The thickest outer region, known as the ‘red zone’ has a high degree of blood supply, while the inner central region is very thin and has much less blood supply. Due to blood supply, the red zone is enriched in nutrients that enable self-healing. The inner (middle) region is referred to as the red-white zone, which contains less blood supply and has minimal self-healing capacity. The innermost region of the meniscus is completely devoid of blood supply and appears to lack the ability to self-repair. The meniscus performs vital functions of shock absorption, mechanical stability, and lubrication to the knee joint. Unlike articular cartilage or coverings on the outside of the bones, the menisci are soft and kept in place by ligamentous attachments, allowing them to slide during knee bending and straightening.
The anterior horn of the medial meniscus attaches near the anterior cruciate ligament (ACL) on the tibia, whereas the posterior horn attaches above the posterior cruciate ligament (PCL). It is very common to also have a meniscal injury when the ACL or PCL ligaments are torn. Meniscus tears are a particular risk for older athletes since the meniscus weakens with age. More than 40% of people 65 or older have tears and degenerative changes in the menisci.
Knee Meniscal Injury
The most common injury to the knee is a tear in the meniscus. Any activity that causes you to twist or rotate your knee forcefully can lead to a tear, especially when you have full weight on that leg. More common are microscopic tears that eventually lead to a tiny piece of cartilage breaking off the size of a piece of sand. Breakdown is part of the natural wear and tear process, but excessive activity combined with poor mechanics will advance this breakdown. Even though this broken piece is tiny, it can cause pain and loss of motion if it interferes with the joint’s smooth mobility and is known as a “derangement”.
Sometimes, a piece of the shredded cartilage breaks loose and catches in the knee joint, causing it to lock up.
When you injure your meniscus, it usually takes 24 hours for your knee to swell and become painful. Pain is usually intermittent and only triggered when the mechanical problem is irritated, rather than constant throbbing pain from inflammation. The following are common signs and symptoms of a torn meniscus:
· Swelling and stiffness
· A popping sensation
· Pain, especially when twisting or rotating your knee
· Pain and inability to fully squat on the involved leg
· Difficulty straightening your knee fully
· Feeling as though your knee is locked in place when you try to move it
· Feeling of your knee giving way
The body has a miraculous way of healing itself. The role of your clinician is to provide education on the best movements and activities that enhance healing and full recovery.
1. Knee Treatment During the Inflammatory Stage:
RICE (rest, ice, compression, elevation)
Inflammation is the body’s initial response to begin the healing process. When an injury occurs the body releases chemicals to clean the area and begin to heal damaged tissues. Inflammation causes constant throbbing pain, swelling, redness, and increased localized temperature. During this acute or inflammatory stage of healing, the treatment protocol is RICE (Rest, Ice, Compression, Elevation). Rest depends on the severity of the injury. Fractures and significant inflammation would require complete rest. But most knee injuries require “active rest” or continuing with light activity within tolerance to prevent muscle wasting and poor healing of tendons.
The inflammatory stage only lasts a few days to a week. As the inflammation reduces, your pain will no longer be constant.
2. Treatment for Derangement – A problem Within the Joint Secondary to a Meniscal Tear
Knee Treatment for Derangements:
1.Reduce the derangement
Your clinician will perform a mechanical assessment to assess which movement will clear the particle from your joint. This is done by performing repetitive movements. The movement that improves your range of motion is the movement that clears the derangment and improves the joint mechanics.
2. Regain full range of motion, strength, and proprioception.
Once the derangment is cleared, full-motion will naturally be restored. The next focus on treatment will be to regain your full strength, balance, and proprioception.
3.Progress to the recovery and return to full activity.
After you have regained full motion, strength and proprioception the final goal will be to aid in your return to full function and sports activity.
Research: Partial Knee Meniscectomies Linked to Early Osteoarthritis
Most studies on arthroscopic meniscectomies are not randomly controlled or compared to sham surgery or conservative care. Below are studies that are randomly controlled and compared to other care.
A recent randomized controlled study just published a few months ago compared partial meniscectomies in those aged 18-45 years to physical therapy and an option to delay surgery. At 24 months, there was no difference between physical therapy and arthroscopic partial meniscectomy. 59% of the randomized PT patients did not choose to undergo delayed surgery. They concluded that physical therapy should be an alternative to early arthroscopic surgery.
Another study out just this month tracked the prevalence of osteoarthritis between 5 and 15 years after arthroscopic partial meniscectomy. Arthritis was found in 23-100% across all periods with increased rates between 10-15 years. They also found that the uninjured knee had a higher rate of osteoarthritis as well and theorized that arthroscopic surgery might lead to bilateral maladaptive movement patterns, potentially affecting the uninjured knee.
Additional studies questioning the value and frequency of arthroscopic partial meniscectomies in favor of conservative care:
2021 Bedrin et al. (Sports Med & Arthroscopy Rev)
Removal of meniscal tissue can also diminish the ability of the meniscus to dissipate hoop stresses, resulting in altered biomechanics of the knee joint including increased contact pressures.
Five-year follow-up found that arthroscopic partial meniscectomy was not superior to placebo surgery, and there is a 13% increased risk of progression of knee osteoarthritis.
2019 Katz et al (Arthritis Rheum)
Five-year outcome of operative and nonoperative management of meniscal tears in patients older than forty-five years: Pain improved in both groups with no significant difference, but the operative group had a greater frequency of total knee replacement surgery.
2017 Beaufils & Pujol. Elsevier
A literature review concluded that a paradigm shift is needed in favor of meniscal preservation. Meniscectomy should no longer be the first-line option.
Exercise therapy versus arthroscopic partial meniscectomy for degenerative meniscal tear in middle-aged patients: a randomized controlled trial with two-year follow-up. No difference was found, and the PT group showed greater quadriceps strength.
2015 Hulet et al (Knee Surg Sports TraumatolArthrosc)
At 20-year follow-up, 56% osteoarthritis was found following lateral meniscectomy.
2013 Sihvonen et al. (N Engl J Med)
146 patients with a degenerative meniscus tear and no evidence of OA were randomized into arthroscopic partial meniscectomy or a sham surgery group. The outcomes after arthroscopic partial meniscectomy were no better than those that underwent a sham surgical procedure.
1998 Charrois, Ayral & Beaufils (Revue de Chirurgie Orthopedique et Reparatrice de L’appareil Moteur)
The authors noted that osteoarthritis is common following meniscectomy. In a multicenter study by the French Arthroscopy Society, joint line narrowing was 22% in the medial meniscus and 40% in the lateral meniscus at a mean of 13 years follow-up.
1995 Rangger, Klestil & Gloetzer AJSM
Partial medial or lateral meniscectomy leads to a significant increase in osteoarthritic changes, even when performed arthroscopically.
The moral is don’t rush in to have surgery. Give your body a chance to do what it knows best – heal. Your ability to heal is miraculous and way ahead of our current technological ability. Seek medical treatment based on conservative care that empowers healing and provides you with education on the best practices to enhance your body’s ability to heal itself. If after you have exhausted conservative care, only then should you consider surgery. But remember partial knee meniscectomies are linked to early osteoarthritis.