Knee problems

KNEE SUMMARY

• Rapid onset swelling (1-4 hours) indicates haemarthrosis (75% are ACL)
• If swelling over 1-2 days after injury, indicates traumatic synovitis
• Locking – inability to extend fully, but able to flex fully. Causes: Torn meniscus (bucket handle), Loose body (eg fragment from osteochondritis dissecans), Torn ACL (remnant)
  • Other: dislocated patella, PFS, MCL tear, ACL strain, effusion
• Catching – consider causes of locking, but subluxing patella and loose bodies in particular
• major knee injuries
  • anterior cruciate ligament (ACL) rupture (52%)
  • meniscal tear (41%)
  • lateral patella dislocation (LPD, 17%)
  • individuals aged ≤17 years were more likely to have LPD, followed by meniscal tear in boys and ACL tear in girls.

Osgood-Schlatter disease 🡪 Consider in prepubertal child with knee pain

Patellofemoral syndrome 🡪 Tracking problem. Commonest type of anterior knee pain. Quad mx

Referred pain to the knee 🡪 Lumbosacral spine, especially L3-S1 nerve root, and hip joint (L3)

Systemic conditions 🡪 OA, RA, spondyloarthropathies, gout, pseudo-gout, lyme disease, sarcoid

Bursitis/tendonitis 🡪 Patellar tendonitis, anserinus tendonitis/bursitis, semimembranous tendonitis/bursitis, biceps femoris tendonitis, quad tendonitis/rupture, popliteus tendonitis, iliotibial band syndrome (runners knee)

Knee Imaging

When a fracture is suspected, an X-ray is recommended as the initial investigation as per Ottawa knee rules:

Knee X-ray indications after acute knee injury include:

1. age ≥55 years
2. tenderness at the head of the fibula
3. isolated tenderness of the patella
4. inability to flex knee to 90 degrees
5. inability to bear weight (defined as an inability to take four steps, ie two steps on each leg, regardless of limping) immediately and at presentation

• knee effusion
  • is an indirect sign of injury. 
  • On X-ray it is best seen in the suprapatellar recess. Of importance is the recognition of a fat-fluid level in the effusion, known as a lipohaemarthrosis
    • represents fat that has escaped from the bone marrow into the joint, which is a specific sign indicating an intra-articular fracture.

A: Lipohaemarthrosis in the suprapatellar recess with fat (black star) and fluid (white stars) producing a fluid level (black arrow). Note that this image is taken with a horizontal beam;

B. Frontal X-ray shows a relatively subtle lateral tibial plateau fracture (white arrows) that might be overlooked if the lipohaemarthrosis was not recognised.

• role of ultrasonography in acute trauma
  • when: superficial structures such as patella tendon or quadriceps tendon suspected
  • is an inexpensive, time-efficient and safe method for assessing superficial structures. 
  • Limitation: limited view
  • Tendon ruptures are also relatively rare and not always clinically considered

• The role of CT
  • useful for characterising the type of fracture. 
  • Useful in search for an occult fracture when magnetic resonance imaging (MRI) is not available
    • typically for patients aged ≥50 years who are suspected of having an insufficiency fracture and who are ineligible for a rebatable scan covered by the Medicare Benefits Schedule (MBS).

• The role of magnetic resonance imaging
  • MRI is the examination of choice for the evaluation of post-traumatic bone pain or instability.
  • high diagnostic yield can be expected in young patients (aged <50 years). 
  • A negative MRI can reassure patients. 
  • Australian Medicare Benefits Schedule criteria for knee magnetic resonance imaging:
    • following acute knee trauma for patients aged 16–49 years with
      • inability to extend the knee suggesting the possibility of acute meniscal tear or 
      • clinical findings suggesting acute anterior cruciate ligament tear
    • for a scan of the knee for a patient aged <16 years for internal joint derangement.

Iliotibial band syndrome

• Iliotibial band friction syndrome is a condition characterized by excessive friction between the iliotibial band and the lateral femoral condyle and presents with activity related lateral knee pain.
• comprises 2-15% of all overuse injuries of the knee region
• most commonly in runners, cyclists and other athletes undergoing exercises with repetitive knee flexion and extension
• pain
  • predominantly localized over the lateral femoral condyle
  • may be exacerbated by changes in running terrain or mileage usually relieved with rest
• Associated conditions
  • patellofemoral syndrome= may be due to tightness of ITB
  • medial compartment osteoarthritis – reduced medial joint space causes varus knee deformities
  • greater trochanteric pain syndrome – alters biomechanics of the ITB
• Differential Diagnosis
  • Biceps femoris tendinopathy
  • Degenerative joint disease
  • Lateral collateral ligament (LCL) injury
  • Meniscal dysfunction or injury
  • Patellofemoral stress syndrome
  • Popliteal tendinopathy
  • referred pain from lumbar spine, stress fractures, and superior tibiofibular joint sprain
  • Knee osteochondritis dissecans
  • Peroneal mononeuropathy
  • Trochanteric bursitis
• Diagnosis is made clinically with tightness of the IT band (Ober’s test)

	hip is brought from flexion and abduction into extension and adduction findings:  positive if pain, tightness, or clicking over the iliotibial band or leg stays in the air

• Management
  • Nonoperative: rest, ice, NSAIDs, corticosteroid injections
  • physical therapy and training modifications
    • deep transverse friction massage
    • strengthening hip aBDuctors
    • proprioception exercises to improve neuromuscular coordination
    • training modifications

Osteonecrosis 

• More common >60yo, aetiology unknown. Sudden onset knee pain with normal XR (diagnostic) 
• Risk Factors
  • Injury. A knee injury — such as a stress fracture or dislocation
  • Oral corticosteroid medications. 
  • medical conditions: obesity, sickle cell anemia, and lupus, medications used for HIV treatment.
  • Transplants
  • Excessive alcohol use
• Pain is usually persistent, with swelling and stiffness, and is worse at night
• Can take 3 months to show up on XR; a bone scan or MRI may be positive earlier. 
• Resolves in time, reduce WB, surgery for persistent pain in early stages

ACL

• Sports with frequent contact (such as football and rugby) and those with high-impact rotation on landing (such as gymnastics) have the highest rates at approximately 2–5 injuries per 10,000 playing hours
• Only 12% of ACL tears are isolated, with meniscal tears being the most common associated injury
• Commonly missed injury – serious and disabling with chronic instability if untreated
• Suspect if a valgus strain or sudden pivoting of the knee, may feel a cracking/popping
• Often has rapid onset haemarthrosis, or inability to weight bear
• Early reconstrunction (at 6/52) if young, otherwise delay, consider if clinical instability.

PCL

• Direct blow to anterior tibia in flexed knee, or severe hyperextension
• MRI to exclude associated injuries (bone avulsion, lateral meniscus, chrondral damage)
• Refer ruptures to ortho/sports physician, don’t need to refer PCL sprains. 
• Usually conservative Mx – immobilise for 6 weeks. Graduated weight-bearing and exercises.

Collateral ligaments 

• If isolated, commonly responds to conservative Tx with early limited motion bracing. 
• 6 weeks of brace at 20-70 degrees, followed by rehab, return to full sporting activity 12 weeks
• MCL always conservative (above) LCL often associated with ACL/PCL, refer to ortho for r/v
• Repair should be done early, but if associated w ACL, early surgery may result in knee stiffness. 

prepatellar bursitis (housemaid’s knee)

• Prepatellar bursitis is the swelling and inflammation of the anterior knee bursa associated with pain with kneeling. 
• Risk factors
  • excessive kneeling – common in wrestlers
• may be septic or aseptic
  • only 20% are septic
• Diagnosis is made clinically with
  • mild swelling and tenderness over the anterior knee overlying the patella
  • Aspiration with gram stain and culture – rarely indicated
    • can be used to distinguish between septic versus aseptic if necessary

• Treatment
  • Nonoperative
    • RICE Method (Level of Evidence 2a)
      • Rest:
        • Short period of immobilization, limited to the first days after trauma.
        • Reduces metabolic demands and avoids increased blood flow to injured tissue.
      • Ice:
        • Decreases tissue temperature, induces vasoconstriction, and limits bleeding.
        • Reduces pain by increasing threshold levels in nerve endings and synapses.
        • Apply ice for a maximum of 20 minutes at a time with intervals of 30-60 minutes.
      • Compression:
        • Decreases intramuscular blood flow and reduces swelling.
      • Elevation:
        • Decreases hydrostatic pressure and reduces accumulation of interstitial fluid.
        • Reduces pressure in local blood vessels and helps limit bleeding.
    • Post-Inflammation Rehabilitation
      • Stretching and Strengthening Program:
        • Restore full motion and improve strength to reduce stress on tendons and knee joint.
        • Includes therapeutic exercises to strengthen and stretch knee muscles.
      • Quadriceps Strengthening:
        • Static contraction of the quadriceps.
        • Exercise to be done at home 1 to 3 times a day.
        • Objective: Resume everyday activities.
        • Technique: Place fingers on the inner side of the quadriceps to feel muscle tighten during contraction.
        • Hold contraction for 5 seconds; repeat 10 times as hard as possible.
        • Exercise must be pain-free.
      • Quadriceps Stretching:
        • Reduces friction between the skin and patella tendon.
        • Increases flexibility of the patella tendon to decrease friction.
    • Electrotherapy Modalities:
      • Used by physiotherapists to aid in pain reduction and healing.
    • Patient Education:
      • Use of knee pads for kneeling activities to protect the knee.
  • Operative
    • bursal resection
  • Prevention
    • Avoid Injury or Muscle Overload:
      • Perform appropriate warm-up and cool down during sports.
      • Example: Wear knee pads during volleyball to prevent falling on the kneecap.
      • Use knee pads if spending a lot of time on knees.
    • Maintain Optimal Flexibility and Strength:
      • Ensure flexibility of the knee and strength/endurance of leg muscles remain optimal.

Meniscal tears

• very common
• most common indication for knee surgery
• medial tears- more common than lateral tears
• lateral tears – more common in acute ACL tears
• Can develop acutely, or due to degeneration of the menisci with only minimal trauma
• Caused by abd/add forces causing compression of meniscus and twisting injury. 
• Age:
  • In younger patients (aged <50 years), meniscal tears typically occur as a result of twisting movements of the knee when under load (weight bearing). 
  • In older patients (aged ≥50 years), tears are more commonly a result of degeneration
• Symptoms
  • pain localizing to medial or lateral side
  • mechanical symptoms (locking and clicking), especially with squatting
  • delayed or intermittent swelling
• Physical exam
  • joint line tenderness is the most sensitive physical examination finding
  • effusion
  • provocative tests
    • Apley compression: prone-flexion compression
    • McMurray’s test
      • flex the knee and place a hand on medial side of knee, externally rotate the leg and bring the knee into extension.
      • a palpable pop / click + pain is a positive test and can correlate with a medial meniscus tear
• Can treat with arthroscopic partial meniscectomy – can be repaired within 6-12 weeks of injury
• Fair to trial conservative mx in small, minimally symptomatic tears over 4/52. 
•  rest, NSAIDS, rehabilitation indicated as first line treatment for degenerative tears

Conservative Treatment

• Strengthening the Quadriceps Muscle: Prevent secondary quadriceps atrophy, especially effective for incomplete or small stable tears in the vascular zone.
• Exercise Therapy: Improve knee function and limit joint pain. Strong evidence supports its role in reducing symptoms and improving muscle strength and physical ability.

Acute Management

• RICE (Rest, Ice, Compression, Elevation): Important in the first 24 hours after an acute soft tissue injury to reduce pain and swelling, especially when blood vessels are damaged.
• Cryotherapy: Apply ice for 20 minutes every 2 hours for the first 48 to 72 hours to decrease tissue temperature and reduce local blood flow through vasoconstriction.

Rehabilitation (Conservative Treatments)

• Strengthening and Stretch Exercises for Quadriceps and Hamstrings:
  • Quadriceps Isometric Exercises:
    • Quad Set: Patient supine, uninvolved knee flexed, involved knee straight; push knee down on the table.
    • Straight-Leg Raise
  • Hamstrings Isometric Exercises:
    • Hamstring Sets: Patient supine, uninvolved knee straight, involved knee in partial flexion; push heel into the table or pillow.
  • Non-weight-bearing Isotonic Exercises:
    • Short-Arc Quad Exercise (Terminal Knee Extensions)
    • Full-Arc Quad Exercise
    • Hamstring Curls
  • Weight-bearing Resistive Exercises (When weight-bearing is possible):
    • Reciprocal Training: Training on a stationary bike.
    • Platform Leg Press, Wall Squats, Plié, Lunge, Step-up, Step-down, Lateral Step-ups
• Flexibility Exercises:
  • Active or Passive Techniques: Improve range of motion and flexibility.
  • Prolonged Extension Stretch: Increase knee extension (prone or long sitting positions).
  • Prolonged Flexion Stretch: Increase knee flexion (depends on present flexion movement).
  • Active Stretches for Quadriceps and Hamstrings.
• Joint Mobilizations:
  • Superior Tibiofibular Joint
  • Patellofemoral Joint: Necessary for full flexion-extension motion of the knee.
  • Tibiofemoral Joint: Most often mobilized to improve knee range of motion.
• Balance & Agility Exercises:
  • Begin with double-support weight-bearing activities.
  • Progress to single-limb static balancing on a stable surface.

Post-Surgical Care

• Meniscus Repair or Meniscectomy (Partial or Full):
  • Expect patient to be on crutches for at least three weeks.
  • Full recovery using a comprehensive rehabilitation program typically takes 3-4 months.
  • Athletes in high-level sports may return to the field around 6-8 months post-operative (verify with the surgeon and specific protocol).
• Rehabilitation Considerations:
  • Rehabilitation plan should be individualized based on the size of the operation.
  • Non-structured rehabilitation after a meniscal repair can lead to increased failure rates compared to well-structured and evidence-based rehabilitation.

Summary for sporting injury:

• MCL and PCL can usually be managed conservatively
• Rarely, small meniscal injuries can be managed conservatively
• Most meniscal, ACL and LCL injuries require surgical management.

Bakers Cyst

• A Baker’s cyst is an enlarged bursa that is normally located between the medial head of the gastrocnemius and a capsular reflection of the semimembranosus, named oblique popliteal ligament.
• Symptoms
  • Vague posterior pain
  • Swelling and a mass in the popliteal space
  • Limited range of motion
  • Stiffness in the back of the knee sometimes increased by activity
  • Tightness behind the knee
• differentials:
  • Thrombophlebitis
  • Popliteal aneurysm
  • Inflammatory arthritis
  • Medial gastrocnemius strain
  • Soft-tissue tumor or muscle tear
• Treatment
  • Observation Most Baker’s cysts will go away on their own. 
  • Activity modification
  • NSAIDS
  • Steroid injection
  • Aspiration
  • Surgical Treatment
  •