Knee pain can be caused by a sudden injury, an overuse injury, or by an underlying condition, such as arthritis. Treatment will vary depending on the cause. Symptoms of knee injury can include pain, swelling, and stiffness.
What is tri-compartmental osteoarthritis of the knee? Osteoarthritis affects the knee joint more than any other joint. If your diagnosis is for tri-compartmental knee osteoarthritis, you will understand your treatment options better with a little lesson on the basic anatomy of the knee.
Anatomy of Knee Pain
There are three compartments of the knee. Each compartment is named after the two bones that join together in that compartment of the knee joint.
The three compartments are
- medial (inside) femoro-tibial compartment
- lateral (outside) femoro-tibial compartment
- patellofemoral compartment (formed by the kneecap and femur)
Osteoarthritis and the Knee Compartments
Osteoarthritis can affect one, two, or three compartments of the knee. When all three are affected, it’s called tri-compartmental osteoarthritis. There are several conservative treatments to help relieve knee osteoarthritis. When conservative treatments fail to be effective, you may be a candidate for knee replacement surgery.
Determining the Affected Knee Compartment
A physical examination may provide the first indication of what compartment is affected. Your doctor will ask you to stand and to walk. While standing, your doctor will observe you for any postural deformity, such as valgus (knock-kneed) or varus (bow-legged) deformity. There may also be obvious or subtle differences in leg length.
When you are asked to walk, your doctor will observe gait abnormalities, such as limping to one side.
X-rays will be needed to confirm cartilage loss and joint damage associated with the abnormalities observed during your physical examination. On x-ray imaging, cartilage loss shows up as narrowing of the space between the ends of the bones forming the joint.
Often, the narrowing of the joint space appears on one side. Medial narrowing is observed in 75% of knee osteoarthritis patients and can cause a bow-legged stance and gait. Lateral narrowing, which is less common and observed in about 26% of knee osteoarthritis patients, is associated with a knock-kneed stance and gait. Close to half of knee osteoarthritis patients have evidence of patello-femoral damage on x-rays.
Surgical Replacement of Affected Knee Compartments
When only one knee compartment is involved, your doctor and an orthopedic surgeon may recommend a partial knee replacement or unicompartmental knee replacement, rather than a total knee replacement. Although the decision to have a partial knee replacement seems straightforward, there are factors to consider. It may be just a matter of time before the other compartments wear out and more surgery is needed. Would it be better to have a total knee replacement rather than a partial knee replacement and not have any concerns about the need for future surgeries?
Your doctor will assess the severity of your condition and offer advice.
Besides a unicompartmental knee replacement or a total knee replacement, there is also a bicompartmental knee replacement. The bicompartmental knee replacement is an option for patients with knee osteoarthritis of the medial and patellofemoral compartments.
Compared to total knee replacement, the unicompartmental and bicompartmental knee replacements preserve normal bone and the two cruciate ligaments.
The Bottom Line
Most knee osteoarthritis patients have unequal involvement of the three knee compartments. Treatment options, especially surgical options, depend on whether you have unicompartmental, bicompartmental, or tri-compartmental knee osteoarthritis.
Range of Motion Explained
Generally speaking, range of motion refers to the distance and direction a joint can move to its full potential. Each specific joint has a normal range of motion that is expressed in degrees after being measured with a goniometer (i.e., an instrument that measures angles from axis of the joint).
Limited Range of Motion
Limited range of motion refers to a joint that has a reduction in its ability to move.
The reduced motion may be a mechanical problem with the specific joint or it may be caused by diseases such as osteoarthritis, rheumatoid arthritis, or other types of arthritis. Pain, swelling, and stiffness associated with arthritis can limit the range of motion of a particular joint and impair function and the ability to perform usual daily activities.
Physical therapy can help to improve joint function by focusing on range-of-motion exercises. The goal of these exercises is to gently increase range of motion while decreasing pain, swelling, and stiffness. There are three types of range-of-motion exercises:
- Active range-of-motion – patient exercises without any assistance
- Active assistive range-of-motion – patient requires some help from therapist to do the exercises
- Passive range-of-motion – therapist or equipment moves patient through range of motion (no effort from patient)
Normal Range of Motion for Each Joint
It’s important to know the normal range of motion for each joint. After physical examination, if it is determined that you have limited or abnormal range of motion in one or more joints, you can put together a treatment plan with your doctor. You can be reassessed for range of motion to determine if the treatment is effective.
Patients who have joint surgery must also go through extensive rehabilitation to get back to normal range of motion in the affected joint.
Recommendations for Treatment of Knee Osteoarthritis
The recommendations pertain to patients having symptomatic knee osteoarthritis — meaning, you have symptoms (such as joint pain, stiffness) — not only X-ray evidence of knee osteoarthritis. The numbering system is from the 2013 Second Edition of the recommendations.
- Rehabilitation, Education and Wellness Activities – Your participation in self-management educational programs is encouraged, and you should modify your activities when possible to protect your joints (for example, walking is better for the joints than running). Strong Pro Recommendation
- Weight Loss – If you are overweight (BMI, body mass index, greater than 25), you should lose a minimum of 5% of your body weight and maintain the lower weight through diet and exercise.
- Acupuncture: The use of acupuncture is not recommended. There is now strong evidence that it does not relieve pain related to knee osteoarthritis.
- Physical agents including electrotherapeutic modalities – have inconclusive evidence, and they can’t recommend for or against them. This includes TENS, shortwave diathermy, inferential current, TAMMEF and ultrasound. Of these, ultrasound had the best evidence, but not convincing.
- Manual therapy – Inconclusive, they cannot recommend for or against. This includes chiropractic therapy, myofascial release, and Swedish massage.
- Valgus Directing Force Brace – A brace such as a medial compartment unloader gets an inconclusive recommendation, neither for nor against.
- Lateral heel wedges are not suggested if you have medial compartment (the inner compartment of the knee) knee osteoarthritis.
- Glucosamine and Chondroitin: Glucosamine sulfate, chondroitin sulfate, and glucosamine hydrochloride are not recommended by AAOS for symptomatic knee osteoarthritis.
- NSAID – Use of non-steroidal anti-inflammatory drugs (NSAIDs) both oral and topical or Tramadol gets a strong positive recommendation
- Acetaminophen, opioids or pain patches: neither for nor against.
- Intra-articular corticosteroids (injected into the affected joint), neither for nor against.
- Viscosupplementation: Cannot recommend intra-articular hyaluronic acidinjections.
- Biologic Injections – Neither for nor against injections with growth factor or platelet-rich plasma.
- Needle lavage – (wash-out of the joint) gets a moderate recommendation, which means practitioners may do it but should be alert for new evidence. The one high-quality study found no measurable benefit.
- Arthroscopy – with debridement or lavage is not recommended to treat symptomatic knee osteoarthritis.
- Arthroscopic partial meniscectomy – If you have signs and symptoms of a torn meniscus or loose body, they can’t recommend for or against this procedure.
- Tibial Osteotomy Limited recommendation – for performing valgus producing proximal tibial osteotomy in patients with medial compartment osteoarthritis. The studies supporting it are of low quality.
- Unispacer – A free-floating interpositional device that compensates for lost cartilage should not be implanted if you have symptomatic unicompartmental knee osteoarthritis. This is a consensus recommendation, meaning there aren’t enough study results for an evidence-based recommendation, but it is made based on expert opinion of the panel.
Normal Values (in degrees)
- Hip flexion (bending) 0-125
- Hip extension (straightening) 115-0
- Hip hyperextension (straightening beyond normal range) 0-15
- Hip abduction (move away from central axis of body) 0-45
- Hip adduction (move towards central axis of body) 45-0
- Hip lateral rotation (rotation away from center of body) 0-45
- Hip medial rotation (rotation towards center of body) 0-45
- Knee flexion 0-130
- Knee extension 120-0
- Ankle plantar flexion (movement downward) 0-50
- Ankle dorsiflexion (movement upward) 0-20
- Foot inversion (turned inward) 0-35
- Foot eversion (turned outward) 0-25
- Metatarsophalangeal joints flexion 0-30
- Metatarsophalangeal joints extension 0-80
- Interphalangeal joints of toe flexion 0-50
- Interphalangeal joints of toe extension 50-0
- Shoulder flexion 0-90
- Shoulder extension 0-50
- Shoulder abduction 0-90
- Shoulder adduction 90-0
- Shoulder lateral rotation 0-90
- Shoulder medial rotation 0-90
- Elbow flexion 0-160
- Elbow extension 145-0
- Elbow pronation (rotation inward) 0-90
- Elbow supination (rotation outward) 0-90
- Wrist flexion 0-90
- Wrist extension 0-70
- Wrist abduction 0-25
- Wrist adduction 0-65
- Metacarpophalangeal (MCP) joints abduction 0-25
- MCP adduction 20-0
- MCP flexion 0-90
- MCP extension 0-30
- Interphalangeal proximal (PIP) joints of fingers flexion 0-120
- PIP extension 120-0
- Interphalangeal distal (DIP) joint of fingers flexion 0-80
- DIP extension 80-0
- Metacarpophalangeal joint of thumb abduction 0-50
- MCP of thumb adduction 40-0
- MCP of thumb flexion 0-70
- MCP of thumb extension 60-0
- Interphalangeal joint of thumb flexion 0-90
- Interphalangeal joint of thumb extension 90-0