Squatting is a fundamental movement that places high mechanical stress on the tibiofemoral and patellofemoral joints. A sudden, sharp jolt of pain during this movement signals an acute structural irritation or injury within the knee. This symptom indicates that a tissue has been compressed, pinched, or acutely strained during deep knee flexion. Understanding the common sources of this discomfort is the first step toward addressing the injury and safely returning to movement.
Anatomical Sources of Sharp Pain During Squatting
The most frequent source of sharp, mechanical pain during deep squatting is a meniscus injury. The menisci are C-shaped cartilage pieces that act as shock absorbers between the femur and the tibia. Deep knee bending, especially with twisting, can pinch or tear this cartilage, causing sudden, stabbing pain as the torn flap gets caught in the joint space.
Sharp pain can also arise from patellofemoral joint dysfunction, often called “runner’s knee,” where the kneecap (patella) does not track smoothly within the femur’s groove. Abnormal tracking causes acute friction or compression on the cartilage behind the kneecap as the knee bends. This irritation manifests as a sharp, burning sensation, often when the knee is flexed between 60 and 90 degrees.
A less common cause is an irritated plica, a fold of synovial tissue. If inflamed, this fold can get acutely pinched between the femur and the patella during squatting, causing a sudden, sharp catching sensation. Acute ligament sprains can also produce sharp pain, especially if the squat involved an unexpected shift that momentarily strained the collateral ligaments.
How to Interpret Pain Location and Accompanying Symptoms
The location of the sharp pain and any accompanying mechanical sensations provide important clues for identifying the injured structure. Pain felt under or around the kneecap (anterior knee pain) often points toward issues involving the patellofemoral joint or the patellar tendon. Tendinopathy, which is micro-tearing of the patellar tendon, is a localized source of anterior pain that worsens under the load of a squat.
Pain localized to the inner (medial) or outer (lateral) side of the knee strongly indicates a meniscal tear or a collateral ligament sprain. The medial meniscus is susceptible to injury during deep flexion and twisting, often resulting in localized joint line tenderness. Pain felt in the back of the knee (posterior) during deep flexion might suggest a meniscal root tear.
Mechanical symptoms like locking, catching, or clicking are highly diagnostic. A true locking sensation, where the knee temporarily cannot be straightened, suggests a piece of torn meniscus or a loose body is physically blocking the joint. Instability or the knee “giving way” under load supports the possibility of a significant structural injury.
Immediate Self-Care and Recognizing When to See a Doctor
The immediate response to sudden, sharp knee pain should focus on protecting the joint and managing acute inflammation using the R.I.C.E. protocol: Rest, Ice, Compression, and Elevation. Rest means immediately ceasing the activity and avoiding any movement that reproduces the sharp pain, potentially using crutches to avoid weight-bearing. Apply a cold pack for 15 to 20 minutes every two hours during the first 48 to 72 hours to minimize swelling and numb the pain. Compression with a snug elastic bandage helps limit swelling but must not cause numbness or tingling. Elevating the leg above the heart promotes fluid drainage and reduces swelling.
It is important to recognize red flags that signal the need for urgent professional medical evaluation:
- An inability to bear any weight on the leg.
- A visible deformity of the knee joint.
- Immediate and significant swelling that occurs within minutes of the injury.
- A distinct audible “pop” at the moment of injury.
- Numbness or coldness in the leg or foot below the knee.
If pain and swelling do not begin to improve after three days of strict self-care, a medical consultation is necessary.
Professional Treatment and Rehabilitation Pathways
Once the acute phase has passed, professional treatment begins with an accurate diagnosis. This typically involves a physical examination followed by imaging studies, such as X-rays to check for bone issues, or an MRI scan to visualize soft tissues like the menisci and ligaments. For most knee injuries causing sharp pain during squatting, conservative management is the initial pathway to recovery.
Physical therapy (PT) is the main element of conservative care, focusing on restoring stability and function to the joint. A PT program emphasizes strengthening the muscles surrounding the knee—particularly the quadriceps, hamstrings, and glutes—to improve joint mechanics and reduce stress on the damaged structure. Exercises are progressed to improve joint mobility and correct underlying movement patterns, such as poor kneecap tracking.
Medical options include anti-inflammatory medications or injections, such as corticosteroids, to manage persistent pain and swelling. For severe injuries, like a significantly torn meniscus that causes persistent locking, surgical intervention via arthroscopy may be necessary. This minimally invasive procedure allows a surgeon to repair or trim the damaged tissue.