PANCE Blueprint Musculoskeletal (8%)

Soft tissue injuries of the knee (ReelDx)

Case Presentation


Knee Pain

A 25-year-old patient presents to the ER with left knee pain

Patellar soft tissue injuries

Prepatellar Bursitis (Housemaid's Knee)

Patient will present as → a 40-year-old female who comes to the clinic with a complaint of swelling and pain at the front of her left knee. She reports that the symptoms began a few days ago and have progressively worsened. She recalls kneeling for an extended period while gardening over the weekend. She denies any recent trauma, fever, or other joint issues. On physical examination, there is pronounced, tender swelling over the prepatellar area without overlying redness or warmth. The range of motion is intact, but pain is elicited with direct pressure over the swollen area. There is no evidence of joint instability, and ligamentous examination is unremarkable. Aspiration of the bursa yields a clear, viscous fluid, and subsequent analysis shows no crystals or signs of infection. The patient is diagnosed with prepatellar bursitis and is advised to avoid prolonged kneeling, use knee pads for protection, and consider taking NSAIDs for pain relief. She is also educated about the importance of ice application and given an option for a compressive wrap to reduce swelling.

Prepatellar bursitis is an inflammation of the bursa in the front of the kneecap (patella)

  • It occurs when the bursa becomes irritated and produces too much fluid, which causes it to swell and put pressure on the adjacent parts of the knee
  • Swelling over the patella. Pain with direct pressure on the knee (kneeling)
  • Common in wrestlers

DX: Concern for septic bursitis in wrestlers - aspiration with gram stain and culture

  • Serum - CBC, serum glucose, CRP, ESR, and uric acid

TX: compressive wrap, NSAIDs, +/- aspiration, and immobilization for 1 weekCorticosteroid use is controversial

  • For immunocompetent patients with mild to moderate infection, oral antibiotic therapy may be administered
Prepatellar bursitis

Prepatellar bursitis, with a reference knee in the background. Caused by a sports injury, fluid was removed in an attempt to treat it, but the bursa was ultimately excised.

References: Merck Manual · UpToDate


Prepatellar bursitis is an inflammation of the prepatellar bursa in front of the kneecap that can be caused by repeated trauma on the flexed knee (e.g., sports injuries, pressure from excessive kneeling). It is also known as Housemaid’s knee. Manifestations include pain and erythema. A minority of the cases can be complicated by septic bursitis from staphylococcus aureus. Aspiration can be done in patients with acute bursitis to rule out infectious causes of gout. NSAIDs are used to manage symptoms, and antibiotics should be added if an infectious etiology is suspected.

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Patellar Tendinitis

Patient will present as → a 30-year-old male who comes to the office complaining of a sharp pain just below the kneecap that started after his regular weekend basketball games. He mentions the pain worsens when jumping or running and has been progressively getting more severe over the past month. He works as a physical education teacher and is very active throughout the week. On physical examination, there is tenderness to palpation at the patellar tendon insertion on the tibial tuberosity. The patient exhibits pain when resisting knee extension and during a squatting maneuver. There is no significant swelling or erythema, and the range of motion of the knee is intact. An ultrasound of the knee shows thickening of the patellar tendon and hypoechoic areas, indicating tendinopathy. Based on the clinical findings, a diagnosis of patellar tendinitis, also known as jumper’s knee, is made. Treatment recommendations include rest, ice, compression, and elevation (RICE), nonsteroidal anti-inflammatory drugs (NSAIDs) for pain management, and a referral to physical therapy for eccentric strengthening exercises. The patient is also advised on the gradual resumption of sports activities and the use of a patellar tendon strap during activities that may aggravate the condition.
An injury to the tissue connecting the kneecap to the shin bone (patellar tendon)

  • Activity-related anterior knee pain associated with focal patellar tendon tenderness. Also known as "jumper's knee" (up to 20% of jumping athletes)
  • It may present with swelling over the tendon and tenderness at the inferior border of the patella
  • Basset's sign: tenderness to palpation at the distal pole of the patella in full extension and no tenderness to palpation at the distal pole of the patella in full flexion

DX: History and physical examination are usually sufficient for diagnosis of infrapatellar tendinitis; however, MRI can show the extent of the injury.

  • Radiographs - AP, lateral, skyline views of the knee - usually normal -may show inferior traction spur (enthesophyte) in chronic cases
  • Ultrasound - thickening of the tendon and hypoechoic areas
  • MRI in chronic cases - demonstrates tendon thickening

TX: Ice, rest, activity modification, followed by physical therapy. Surgical excision and suture repair as needed

  • Cortisone injections are contraindicated due to the risk of patellar tendon rupture
Jumpers knee

Jumper's knee

References: Merck Manual · UpToDate

Patellofemoral Pain (PFP)

Patient will present as → a 20-year-old female college student and recreational runner who reports experiencing a dull, aching pain around her kneecap that has been worsening over the past 3 months. She describes the pain as being particularly noticeable when she is climbing stairs, squatting, and sitting with her knees bent for prolonged periods during her lectures. She denies any specific injury but notes that the pain began when she increased her running mileage. Her medical history is unremarkable. On physical examination, there is pain on palpation of the patellar borders and slight swelling of the anterior knee. There is also a positive patellar compression test. Strength testing reveals mild quadriceps muscle weakness, and flexibility tests show tightness in her hamstrings and iliotibial band. No signs of instability or effusion are present. Conservative treatment is initiated with activity modification, quadriceps-strengthening exercises, hamstring and iliotibial band stretching, and instructions on proper footwear. The patient is advised to avoid activities that exacerbate symptoms and to gradually return to running, following a program that includes a proper warm-up and cool-down routine.
Patellofemoral joint pain can be defined as anterior knee pain involving the patella and retinaculum that excludes other intraarticular and peripatellar pathology

  • Caused by a combination of factors that lead to overuse and stress on the patellofemoral joint
  • Commonly seen in young athletic women
  • Commonly seen in runners or cyclists
  • Pain is poorly localized anterior knee pain, which worsens with squatting, running, prolonged sitting (theater sign), and climbing stairs
"The term chondromalacia patella is used to describe pathologic changes in the articular cartilage of the patella, such as softening, erosion, and fragmentation. While frequently confused with PFP, chondromalacia patella is a pathologic diagnosis and constitutes a distinct cause of knee pain. - UpToDate"

DX: Although PFP is a clinical diagnosis, the diagnosis can be supported by the patellofemoral compression test (reproduction of the pain with compression of the patella during knee extension)

TX: Treatment is usually conservative with the use of physical therapy, weight loss, NSAIDs, and support braces

© Pepermpron by Adobe Stock

References: Merck Manual · UpToDate

Patellofemoral Pain Syndrome

Patellofemoral Pain Syndrome, or PFPS, is an overuse injury of the knee, commonly seen in young athletic women. Pain in this syndrome is primarily poorly localized anterior knee pain, that worsens with squatting, running, prolonged sitting, and climbing stairs. Although PFPS is a clinical diagnosis, the diagnosis can be supported by the patellofemoral compression test and the apprehension sign. Treatment is usually conservative with the use of physical therapy, weight loss, NSAIDs, and support braces.

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Ligament/Meniscal injuries

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Anterior Cruciate Ligament (ACL) Tear

Patient will present as → a 22-year-old female soccer player who reports a “popping” sensation in her knee followed by immediate swelling after pivoting awkwardly during a game yesterday. She states that her knee “gave out,” and she was unable to continue playing. She has experienced significant pain and has had difficulty bearing weight on the affected leg. She denies any previous knee problems. Medical history is unremarkable. On physical examination, her knee is swollen and warm to the touch, with a noticeable effusion. A Lachman test shows a significant increase in anterior translation of the tibia when compared to the unaffected leg, and the pivot-shift test elicits a feeling of instability and is positive. Magnetic resonance imaging (MRI) of the knee confirms a complete tear of the anterior cruciate ligament. The patient is referred to an orthopedic surgeon for evaluation of surgical options and is advised on the importance of pre-surgical physical therapy to reduce swelling and improve the range of motion.
An ACL tear is a common sports injury that occurs when the anterior cruciate ligament (ACL) in the knee is torn. The ACL is one of four ligaments that connect the thighbone (femur) to the shinbone (tibia) and helps stabilize the knee joint. ACL tears are often caused by sudden changes in direction, pivoting, or landing from a jump

  • Pop and swelling along with instability or "giving out" the knee after a quick plant and twist injury
  • Quickly stopping movement and changing direction while running, landing from a jump, or turning leads to rotation or valgus stress of the knee and can result in injury to the ACL. Common in skiers, football, and basketball players
  • Contact injury that causes hyperextension or valgus deformation of the knee


  • Anterior Drawer Test: the proximal tibia is anteriorly pulled while the patient is supine and the knee is flexed at 90 degrees – if there is anterior translation, then the test is positive
  • Lachman’s Test (most sensitive): the proximal tibia is anteriorly pulled with one hand, while the other hand stabilizes the distal femur while the knee is flexed at 30 degrees
  • Lateral Pivot-Shift Test: The test is performed by passively moving the tibia anteriorly and internally while the knee is flexed and then observing for a sudden reduction of the tibia at around 30-40 degrees of flexion. If the tibia subluxates anteriorly and then reduces spontaneously, the test is considered positive

**Segond fracture is an avulsion fracture of the knee that involves the lateral aspect of the tibial plateau and is frequently (~75% of cases) associated with ACL tears

DX: Magnetic resonance imaging (MRI) can confirm the diagnosis

  • Physical therapy and lifestyle modifications for low-demand patients with decreased laxity.
  • Surgical reconstruction is performed in young and active patients with high-demand sports or jobs and/or significant knee instability.

(watch a video of the ACL exam)

ACL tears are often caused by the combination of knee abduction, ankle eversion, and femoral adduction (image © VectorMine by Adobe Stock)

Image – The anterior cruciate ligament (ACL) is not seen in the notch of the knee (arrow) by Chang et al. License: CC BY 2.0

References: Merck Manual · UpToDate

Question 1
A 33-year-old male presents to your office with a complaint of right knee injury associated with pain and swelling. He states he was running after his loose dog and suddenly stopped, hyperextended his knee, heard a pop and noticed immediate swelling. On physical examination, the Lachman test and anterior drawer test demonstrates joint laxity. Which of the following ligaments is most likely injured?
Medial collateral
Medial collateral ligament injuries often occur with rotational injuries or direct impact to the lateral knee. Tenderness medially with laxity with valgus (medial) stress is noted.
Lateral collateral
Lateral collateral ligament injury causes pain mostly on the lateral aspect of the knee and patients can experience knee buckling with normal gait. Tenderness laterally with laxity with varus (lateral) stress is noted.
Posterior cruciate
Posterior cruciate ligament injuries occur with an outside directed force, often a posterior directed force such as a knee striking a dashboard. The patients often do not hear a pop. A posterior drawer test or posterior sag test can be useful in the diagnosis.
Anterior cruciate
Question 1 Explanation: 
Anterior cruciate ligament injuries occur with sudden deceleration injuries. Patients often hear a pop and the diagnosis is aided by assessing the anterior drawer test and Lachman test. The immediate swelling as well as laxity with anterior drawer test and Lachman test should raise suspicion of anterior cruciate ligament injury.
There is 1 question to complete.
Shaded items are complete.
Anterior cruciate ligament (ACL) tear


The ACL stabilizes the knee by resisting hyperextension and anterior dislocation of the tibia during flexion. Injuries typically occur during non-contact sports such as basketball and soccer, but can also occur from trauma.

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Medial Collateral Ligament (MCL) Tear

Patient will present as → a 26-year-old college football player who is brought to the emergency department after being hit on the lateral side of the left knee. He reports hearing a pop, and then his knee buckled. He is now in severe pain and is having difficulty walking. On examination, there is swelling over the medial aspect of the left knee. There is laxity when a valgus stress test is performed on the knee. The results of the Lachman and McMurray tests are negative. You order an MRI of the knee with results seen here
The MCL is a thick band of tissue that runs along the inner side of the knee and stabilizes the joint. MCL tears are common in sports that involve contact or sudden changes in direction, such as football, basketball, and soccer. They can also occur from a fall or other direct blow to the outside of the knee

  • Patient will present → after sustaining a valgus stress injury (from the outside), such as a hit in football
  • Results when the knee is forced into valgus and external rotation force to the lateral knee
  • A "pop" reported at the time of injury, along with medial joint line pain and difficulty ambulating due to pain or instability
  • Testing: Valgus stress test - The patient will have pain with valgus stress applied to the knee
    • The examiner places one hand at the outside of the knee, acting as a pivot point, while the other hand is placed at the foot. The medial joint line is palpated while the examiner simultaneously applies an abducting force at the foot, and a valgus (medially directed) force through the knee joint.

DX: MRI definitive study

TX: Conservative treatment with bracing and physical therapy is typically effective

  • Surgery for chronic instability

(watch video of MCL exam)

MCL tears are common in sports (such as football) as a result of a direct blow to the outside of the knee (image © Pepermpron by Adobe Stock)

Image – MRI showing medial collateral ligament injury and displacement of the lateral meniscus by Matthijs R. Douma et al. License: CC BY 4.0

References: Merck Manual · UpToDate

Medial collateral ligament (MCL) tear


A medial collateral ligament (MCL) tear is an injury of the ligament that connects the femur to the tibia on the medial aspect of the knee. It occurs in patients that have experienced high-energy trauma. It is typically treated conservatively and can be clinically observed with the valgus stress test.

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Lateral Collateral Ligament (LCL) Tear

Patient will present as → a 25-year-old soccer player who injures his knee after colliding with an opposing player during a game. On physical exam, his Lachman is weakly positive. He has laxity to varus stress with the knee flexed to 30 degrees. Dial test of the tibia shows increased external rotation at 30 degrees but not at 90 degrees in comparison to the contralateral leg.
The lateral collateral ligament (LCL) is a strong band of tissue that connects the thighbone (femur) to the fibula, one of the two bones in the lower leg. An LCL tear is a common injury, especially among athletes who participate in sports that involve cutting, pivoting, or contact.

  • The main cause of LCL injuries is direct-force trauma to the inside of the knee, causing excessive varus stress, external tibial rotation, and/or hyperextension
  • Isolated injury is extremely rare - 7-16% of all knee ligament injuries when combined with lateral ligamentous complex injuries, particularly posterolateral corner (PLC) injury
  • Testing: Varus stress test
    • Flex the knee to 30 degrees. Grasping the medial aspect of the knee with one hand and the ankle with the other, apply a varus (laterally directed) force to the medial aspect of the knee. Abnormal If a gap is created in the lateral knee joint or if pain is produced.

DX: Radiographs - AP, lateral, and varus stress radiographs

  • MRI definitive study - provides information about severity (complete vs. partial rupture) and location (avulsion vs. midsubstance tear)

TX: Conservative treatment with bracing and therapy is typically effective

  • All start early PT
  • Grade I: 2-4 weeks immobilization → quad strengthening
  • Grade II: brace blocking last 20 degrees of flexion, weight-bearing as tolerated
  • Grade III: Surgery - Limit weight-bearing after surgery for 6 weeks, brace for at least 3 weeks

(watch video of LCL exam)

Image of MRI showing lateral collateral ligament (LCL) rupture at the fibula head (arrowheads) and substance of the LCL (arrows) by Takeshi Oshima et al. License: CC BY 3.0

References: Merck Manual · UpToDate

Posterior Cruciate Ligament (PCL) Tear

Patient will present as → a 22-year-old recreational soccer player who sustained a right knee injury 6 months ago. He has been treated with rest and rehabilitation but is unable to play at his previous level due to his knee “giving way.” Physical exam reveals 10° varus alignment when standing and a varus thrust with walking. Strength is full compared to the other side. Ligamentous exam reveals a stable ACL and MCL but opens to a varus stress and a 3+ posterior drawer and positive dial test at both 30° and 90° degrees of flexion.
The posterior cruciate ligament (PCL) is located at the back of the knee and helps to prevent the shinbone from moving backward too far

  • PCL injuries can also result from a blow to the knee while it is flexed or bent, such as landing hard during sports or a fall or from a car accident (also known as dashboard knee). May result from non-contact hyperflexion with a plantar-flexed foot or a hyperextension injury
  • Testing: Posterior drawer test, sag sign (tibia sagging posteriorly), active quad test
    • The posterior drawer test is used to assess the integrity of the posterior cruciate ligament. With the knee flexed to 90 degrees and the foot stabilized (often the examiner sits on the patient's foot), the proximal tibia is grasped firmly with both hands and the tibia is forcibly pushed posteriorly, noting any laxity compared with the other side

DX: MRI is the confirmatory study for the diagnosis of PCL injury

TX: Protected weight bearing and rehab indicated for isolated Grade I (partial) and II (complete isolated) injuries

  • Surgical repair for PCL + ACL or PCL injuries and PCL + Grade III MCL or LCL injuries
  • Minimum 3 months rehab before return to play of sport

(watch video of PCL exam)

PCL injuries can also result from a blow to the knee while it is flexed or bent (image © Aksana by Adobe Stock)


Ligamento Cruzado Posterior

MRI demonstrating tear of the posterior cruciate ligament

References: Merck Manual · UpToDate

Meniscal Tear

Patient will present as → a 30-year-old male who reports knee pain and locking after twisting his knee while playing basketball a week ago. He mentions that the pain is localized to the medial side of the knee and has been persistent since the injury. The patient also experiences locking and discomfort when squatting. Medical history includes mild osteoarthritis. On physical examination, there is tenderness along the joint line, and McMurray’s test reproduces pain and a clicking sensation. The Apley grind test is also positive for reproducing pain and a sense of roughness on rotation of the foot with applied axial pressure. An MRI of the knee reveals a horizontal cleavage tear of the medial meniscus. Conservative management, including rest, ice, compression, and elevation (RICE) is initially recommended along with nonsteroidal anti-inflammatory drugs (NSAIDs). The patient is referred to physical therapy for exercises to strengthen the quadriceps and hamstrings. An orthopedic consultation is advised for possible arthroscopic evaluation and repair due to the mechanical symptoms.
The meniscus is a C-shaped piece of cartilage that acts as a shock absorber between the shinbone and thighbone. Meniscal tears are most commonly caused by twisting the knee while playing sports or landing awkwardly on the knee after a fall

  • After a twisting injury Associated with locking and a feeling of the knee giving away. Walking up and down stairs or squatting is difficult and painful
  • Triad of joint line pain, effusion, locking
  • Effusion typically 6-24 hours after injury
  • Roughly 1/3 experience locking
"MCL tears are often part of the "terrible triad," which includes an anterior cruciate ligament tear, medial collateral ligament tear, and meniscus tear"


  • McMurray test (watch video): the patient is supine, knee flexed and externally (medial meniscus) or internally (lateral meniscus) extended - pain indicates a tear
  • Apley compression test (watch video) will be positive: Pt prone, knee to 90 degrees, axial load with rotation causes pain with meniscal pathology

DX: Radiographs of the knee, possibly including sunrise, tunnel, posteroanterior, weight-bearing anteroposterior, and lateral views

  • MRI is the definitive study

TX: If the tear is not serious, physical therapy, compression, elevation, and icing of the knee can heal the meniscus

  • More serious tears may require surgical repair
  • Return to full function may be expected in 6–8 weeks
  • High risk of osteoarthritis if meniscectomy at a young age

Meniscal tears are most commonly caused by twisting the knee while playing sports or landing awkwardly on the knee after a fall. (image © designua by Adobe Stock)

MBq korbhenkelriss

Basket handle tear of the lateral meniscus (red). Slight signs of wear – no rupture – of the medial meniscus (green).

References: Merck Manual · UpToDate

Meniscal Tear


The menisci are fibrocartilage semicircular bands that serve to stabilize the knee and absorb forces between the distal femoral condyles and the proximal tibial plateau of the knee. Injury can be sustained from trauma or in a degenerative manner. Symptoms include locking and clicking, as well as a positive McMurray test. Meniscus tears are typically managed conservatively, or in serious cases, surgery.

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