Column: Knee Injuries: What to Know, How to Treat

By Moira McCarthy, MD

You’re bombing down the ski slopes, it’s the last run of the day, maybe the last of the season, and then it happens. You hit an ice patch, lose control and tumble hard in the snow. Then you find yourself clutching your knee.

Across all levels of sports, knee injuries are one of the most common — from elite to young athletes to weekend warriors. Understanding the most common knee injuries and how to treat them can help get you back on the slopes or field safely and effectively.

Some of the knee problems we see commonly at HSS are ACL tears, meniscus tears, and chronic knee pain. Let’s look at each and the recommended treatment options.

Anterior Cruciate (ACL) Tears

The anterior cruciate ligament or ACL is part of a group of ligaments that connect the thigh bone or femur to the lower leg or tibia. These ligaments stabilize and support the knee joint.

It’s estimated that there are 100,000 to 200,000 ACL tears in the U.S. each year. Athletes who play pivoting sports like soccer, lacrosse, basketball, field hockey and skiing are especially vulnerable.

When an ACL injury happens, the athlete may hear a popping noise after an awkward twist, collision or fall. Immediate symptoms are pain and swelling in the knee. In most cases, we recommend surgery as the best way to stabilize the knee joint and resume an active lifestyle.

The first step is to examine and diagnose the problem by taking x-rays to ensure no bones are broken. Then we get an MRI to look at the soft tissues around the knee. Once imaging is completed, a few weeks of physical therapy is recommended to help improve range of motion and regain some muscle function. If ACL surgery is required, rehabilitation will immediately follow. We want an athlete walking normally in six weeks, running in three to four months, and back to play in 9-12 months. HSS Rehab conducts “return to sport” testing on patients, using motion capture to assess strength, quality of movement and risk factors for recurrent injury. Athletes who have had an ACL injury are more prone to a second one, so we want to help reduce recurrence.

Meniscus Injuries

There are two menisci inside each knee joint. They are soft cushions on the inside of the knees that protect the cartilage. Meniscus tears are very common with all types of activity. A torn meniscus can be categorized as traumatic (acute) or degenerative (associated with aging or wear and tear). In both cases, pain is on one side of the knee and motion can be decreased. Significant swelling can occur, but not always.

Traumatic meniscus tears are generally treated surgically to improve quality of life and preserve some of the function of the meniscus. Degenerative tears can be treated with or without surgery based on other factors such as age, activity level, amount of other degeneration in the knee, and level of symptoms.

Recovery from surgical meniscus repair can range from several weeks to several months and requires good quality physical therapy.

Chronic Knee Pain

Many of the patients we see at HSS with knee pain are suffering early arthritis, which we also call cartilage softening or thinning. Other conditions like patella tendonitis and quadriceps tendonitis can cause knee pain, hindering activities like climbing stairs, squatting, jumping, and running.

We generally treat chronic conditions conservatively with oral anti-inflammatories, physical therapy, and activity modification. Other treatments such as different kinds of knee injections can help lubricate the knee joint to relieve pain and stiffness. We advise a program to strengthen muscles around the knee and teach patients to better use their muscles to avoid overloading certain parts of the knee.


Moira M. McCarthy, MD, is a sports medicine surgeon at HSS Orthopedics at Stamford Health, specializing in arthroscopic and open knee and shoulder surgery.

Related Posts