Articular Cartilage Damage

DEFINITION

• Articular cartilage damage occurs either by acute trauma or by degenerative changes.

• Osteoarthritis occurs when progressive erosion and loss of the articular cartilage lining the ends of the femur and the tibia occur.

• Trauma can include damage to the cartilage or underlying bone.

Articular-Cartilage

SYNONYMS

• Osteochondral lesion

• Osteochondral fracture

• Osteochondritis dissecans (OCD)

• Osteoarthritis

• Degenerative joint disease

ETIOLOGY

• Degenerative Cartilage destruction results from a combination of excess or abnormal biomechanical and biochemical forces on weight-bearing surfaces.

• Erosion and loss of cartilage is progressive over time and more commonly occurs in the medial compartment of the knee.

• Once osteoarthritis begins, the rate of tibial cartilage loss per year markedly increases in comparison to healthy knees.

• Osteoarthritis occurs when catabolism exceeds cartilage synthesis. Cytokines (proteolytic digestion of cartilage),growth factors (cartilage repair/synthesis), and collagenolytic enzymes (cartilage breakdown) play a role in the pathophysiology of the pathology.

• Structural changes include joint space narrowing, osteophytes, and subchondral bone cysts and sclerosis.

• Traumatic Osteochondral fractures usually occur on weight-bearing surfaces. Surfaces commonly injured include the lateral talus, patella, femur, or tibia.These fractures commonly involve both the articular cartilage and its underlying bone. Generally, only one fracture occurs at a time.

• OCD most commonly occurs secondary to a compressive type of trauma. 

Knee-Osteoarthritis

The pathophysiology of OCD involves the following three stages:

• Stage 1:

 Thickening and swelling of the intraarticular and periarticular structures. Thinning of the adjacent metaphysis.

• Stage 2: 

Thinning and disruption of the subcortical zone of rarefaction. Fragmentation of the epiphysis and disruption of blood flow to the epiphysis.

• Stage 3: 

Repair in which granulation tissue replaces necrotic tissue.

• In the knee joint, the medial femoral condyle is the most commonly involved site,occurring 75% of the time. OCD rarely occurs on the medial tibial plateau.

EPIDEMIOLOGY AND 

DEMOGRAPHICS

• Osteoarthritis is the most common joint disorder in the world.

• Approximately 11% of individuals older than 64 years have symptomatic osteoarthritis of the knee.

• Risk factors associated with aggressive progression are high body mass index (BMI),meniscal lesion, and subchondral bone marrow edema.

• Other risk factors associated with the development of osteoarthritis are female gender,previous joint injury, and age.

Painful-Knee

• In femoral condyles,OCD has been estimated to occur in 6 per 10,000 men and in 3 per 10,000 women younger than 50 years.

• OCD of the ankle occurs in 2 per 100, [2 per 100,000],regardless of age and sex.

• OCD average age of occurrence is in the mid-20s.

MECHANISM OF INJURY

• Degenerative

• Primarily nontraumatic, insidious onset, and progressive with age.

• Patients with a previous history of knee trauma or surgery are at greater risk of developing osteoarthritis at an earlier age.

• Traumatic

• In the knee, osteochondral fractures typically result when you twist your knee badly.

• Direct trauma (sudden, forceful injury) to the inner or outer part of the femur at the knee can lead to these lesions.

• In the ankle, these fractures occur by a force directed from the joint surface of the tibia (shin bone), across the joint, and into the talus.

• Most osteochondral fractures to the outer side of the talus result from trauma. Injuries to the inner side of the talus may result from a recurring ankle injury such as a sprain.

• OCD commonly occurs as a result of compressive loading of the joint and cartilage.

COMMON SIGNS AND 

SYMPTOMS

• Knee joint pain and effusion

• Crepitus

• Grinding

• Clicking

• Decreased ROM

• Pain with weight-bearing activities

• Morning stiffness lasting 30 minutes or less

• Joint instability or buckling

• There is generally no referral pattern for osteoarthritis of the knee.

AGGRAVATING ACTIVITIES

• Prolonged walking or standing

•Stairs

• Squatting

• Sit to stand

EASING ACTIVITIES

• Non–weight-bearing activities

• Rest

• Heat or ice, depending on stage of healing.

24-HOUR SYMPTOM PATTERN

 Morning stiffness that lasts <30 minutes.

PAST HISTORY FOR THE REGION

• Meniscal damage

• Knee surgery or trauma

PHYSICAL EXAMINATION

• Decreased ROM

• Joint enlargement or deformity

• Tenderness to palpation at the medial or lateral joint line

• Palpable joint effusion

• Degenerative

• Radiographic features: loss of joint space,sclerosis, and osteophytes

• Traumatic

• Evidence of lesions or fractures.

Knee-Pain

IMPORTANT OBJECTIVE

 TESTS

• Degenerative

• Radiographic features: Loss of joint space,sclerosis, and osteophytes.

• Positive McMurray’s test: Osteoarthritis is often associated with meniscal derangement.

• Traumatic

• X-rays often show no sign of OCD therefore,computed tomography (CT) scans, magnetic resonance imaging (MRI), and ultrasound are often recommended to rule out the presence of OCD.

DIFFERENTIAL 

DIAGNOSIS

• Meniscal derangement

• Patellofemoral pain syndrome

• Referred pain from hip joint pathology

TREATMENT

SURGICAL OPTIONS

• Total knee arthroplasty (TKA).

• Unicompartmental knee arthroplasty

(partial knee replacement)

• Arthroscopic debridement and chondroplasty.

• Microfracture

• Osteotomy

INDICATIONS FOR SURGERY

• TKA is indicated in cases of severe arthritis with total loss of cartilage and significant functional limitation.

• Unicompartmental knee replacement is recommended when arthritisislocalized to only one side of the knee,the patient is not obese, and ligaments are intact.

• Osteotomy: Joint damage is localized to only one side, leading to either a genu varum or genu valgum deformity in the knee.The patient is typically active and younger, and the purpose of this procedure is to delay progression of arthritis and the need for a total knee replacement.

• Arthroscopy is generally performed on mild cases of osteoarthritis or OCD to remove loose bodies and debris and to trim damaged cartilage.

• Surgery may be required to remove the intraarticular loose body and/or correct the resulting degenerative changes

SURGICAL OUTCOME

• Total and partial knee arthroplasties typically result in good long-term outcomes.

• Partial knee replacements have a faster recovery rate because of the less-invasive nature of the procedure.

• In total knee replacements, >90% of patients have successful outcomes and are able to return to low-impact activities.

Arthroplasty-Knee

• Arthroscopic debridement and chondroplasty: Review of literature reveals that this may not be effective in treating knee osteoarthritis.

• Osteotomy: Candidates for surgery must be very carefully selected to ensure a successful outcome.If the surgery is successful,the results of the surgery can last from 8 to 10 years.

Total-Knee-Replacement

REHABILITATION

• Treatment for OCD and degenerative changes to cartilage are both similar.

• Goals:

- Restore ROM and strength.

- decrease pain and swelling, and reduce stress to the knee joint to delay progression and promote healing for return to normal function.

• Initial exercises used to promote healing are as follows: 

• ROM and strengthening exercises within limited weight-bearing conditions (open kinetic chain) promote joint lubrication and decrease stress on the menisci and articular cartilage.

• Avoid exercises involving heavy loads with rotation to the knee joint if meniscal damage is present.

• Stationary bicycle

• Aquatic therapy

• Low-load knee flexion/extension exercises in supine: Heel slides, quad sets, straight leg raises, bridging, leg press in supine.

TKR-Rehabilitation

• Hamstring and quadriceps stretching.

• Recommendationsto the patient to delay the progression of osteoarthritis and achieve optimal outcomes after surgery.

• Weight loss

• Proper footwear to maximize shock absorption during gait; avoid high heels.

• Assess the need for custom or over-the-counter foot orthotics to decrease medial or lateral knee joint stress.

• Participate in low-impact activities and avoid high-impact,repetitive activities such as running and jumping.

Strength-Exercises

PROGNOSIS

• For partial and total knee replacements, prosthetic survival rates typically range from 10 to 15 years.

• OCD and osteochondral fractures have excellent prognosis for full recovery.

SIGNS AND SYMPTOMS 

INDICATING REFERRAL 

TO PHYSICIAN

• Postoperative indicators

• Signs of infection: Excessive pain, swelling,redness,fever, malaise.

• Signs of deep vein thrombosis (DVT): 

• Calf pain/tenderness, redness, and swelling.

• Failure to respond to conservative treatment.