ACL Specialist

Jonathan T. Nassos, M.D. -  - Orthopaedic Surgeon

Jonathan T. Nassos, M.D.

Orthopaedic Surgery and Sports Medicine located in Los Angeles, CA & Sherman Oaks, CA

Hearing a “popping” sound in your knee followed by pain and an inability to put weight on the knee is a sure sign of an ACL injury. The knowledgeable doctors at Nassos Orthopaedic Surgery in the Beverly Grove Area, Los Angeles, California, offer ACL injury diagnosis and repair options. If you’re experiencing knee pain and suspect an ACL injury, give the provider a call, or use the convenient online booking feature to schedule an appointment.


What is an ACL?

The anterior cruciate ligament (ACL) stabilizes your knee joint and enables full range of motion. The ligament connects your thigh bone to your shin bone. The ACL looks like a braided rope made of long collagen strands woven together and has the ability to withstand up to 500 pounds of force. 

What increases risks for ACL injuries?

People who participate in sports such as football, downhill skiing, soccer, gymnastics, and basketball are at higher risk for ACL injuries. Females are at higher risk for ACL injuries than males, possibly because of hormonal influences or the tendency to have weaker muscle strength. Other factors increase your risk of an ACL injury, including:

  • Wearing ill-fitting or unsupportive footwear
  • Poor fitness
  • Participating in sports activities on artificial turf surfaces
  • Using poorly maintained sports equipment

What causes an ACL injury?

A tear or sprain of the ACL is a common knee injury that often happens during fitness activities or sports participation that puts stress on the knee. Common causes of ACL injuries include:

  • Making a sudden change in speed and direction
  • Pivoting while keeping your foot firmly in one place
  • Stopping suddenly
  • Landing poorly when jumping
  • Receiving a hit to the knee, such as in a football tackle

Many people with ACL injuries feel their knee pop at the time of injury, and some even hear a popping noise. The knee may swell, and it can become too painful to bear weight. If you experience a suspected ACL injury, give Nassos Orthopaedic Surgery a call, or use the online booking tool to schedule an appointment for diagnosis and treatment.

What are the symptoms of ACL injuries?

If you damage your ACL, you’ll experience decreased range of motion, swelling of the knee, weakness when putting weight on your knee, and pain. You will not likely continue normal activities after an ACL injury.

How are ACL injuries diagnosed?

Your doctor will look for knee swelling, tenderness, and compare the injured knee to your uninjured knee. If a diagnosis cannot be made based on the physical exam, Nassos Orthopaedic Surgery will conduct tests to determine the severity of the injury, including:

  • Ultrasound
  • X-rays to rule out bone fractures
  • Magnetic resonance imaging (MRI)

How are ACL injuries treated?

Prior to visiting the doctor, treat ACL injuries at home with rest, ice on the knee every two hours for 20 minutes at a time, and keeping your knee elevated. ACL surgery is recommended if your injury causes the knee to buckle during normal activities, if more than one ligament in your knee is injured, or if you’re an athlete and want to continue participation in the sport.

ACL reconstruction surgery involves removing the damaged ligament and replacing it with a graft, which is a segment of tendon taken from another part of your knee. After surgery, you’ll need rehabilitative therapy to restore stability and function to the repaired knee and prevent injury to the other knee.

Though some ACL injuries may heal on their own through rest, ice, and therapeutic knee exercises, some will require surgical intervention. Make an appointment with the team at Nassos Orthopaedic Surgery to determine the best course of treatment for your ACL injury.