Joints and Movement: Why Do They Hurt and What Can We Influence?

Joint pain does not always mean “worn-out cartilage”

Does your knee hurt when you walk? Does your hip feel stiff after sitting? Is movement less comfortable than it used to be?

Joint pain is often explained with one simple sentence:

In reality, movement depends on a connected system of joints, cartilage, bones, muscles, tendons, ligaments, fascia and the nervous system.

A joint is a complete functional system. Pain may come from muscles, tendons, ligaments, bone, the joint capsule, bursae or other nearby structures—not only from cartilage.

Osteoarthritis is not simply mechanical wear of cartilage. It is a condition involving the whole joint, including cartilage, subchondral bone, the synovial membrane and other structures.

Osteoarthritis does not automatically mean that the joint should not be used. Appropriate movement is an important part of care, but its type and intensity should match the individual situation.

Saying “my knee hurts” does not identify the structure causing the pain. Possible sources include a muscle, tendon, attachment site, ligament, bursa, meniscus, bone or the joint itself.

A functional assessment by a physiotherapist or doctor can be valuable when pain persists.

The musculoskeletal system works as a chain:

Limited ankle mobility or poorly functioning hip muscles can change knee mechanics. This is why an experienced clinician often assesses more than the painful area.

Short-term rest may sometimes be appropriate, but prolonged inactivity can reduce muscle strength and general fitness.

The goal is to find the amount and type of movement the joint currently tolerates and to adjust the load gradually.

Strong, well-coordinated muscles help stabilise joints and manage mechanical load. For the knee, this includes the thigh muscles, gluteal muscles, hip muscles, calves, foot muscles and trunk stabilisers.

A good rehabilitation programme may involve the whole body rather than only “ten exercises for the knee”.

Mild discomfort does not always mean new tissue damage, but severe or worsening pain should not be ignored.

If symptoms worsen substantially and remain worse, the new load may have been too high.

Body weight affects mechanical load on weight-bearing joints. Adipose tissue is also metabolically active, so the relationship is not purely mechanical.

The aim is not to focus only on a number on the scale, but to combine realistic weight management, movement and preservation of muscle mass.

Articular cartilage has no direct blood supply like muscle tissue. Nutrient and metabolite exchange involves synovial fluid, diffusion and repeated cycles of loading and unloading.

Complete immobility is not an ideal long-term solution. A joint needs appropriately dosed activity and enough time to recover.

Maintaining muscle mass becomes increasingly important with age. Muscles help stabilise joints and handle everyday mechanical demands.

Long-term joint care should therefore consider nutrition, muscle mass and regular movement—not cartilage alone.

Collagen is a major structural protein found in skin, tendons, ligaments, bone and cartilage. Hydrolysed collagen and collagen peptides are also studied in relation to the musculoskeletal system.

Drunk collagen does not “stick” directly to damaged cartilage. It undergoes digestion, absorption, transport and metabolism. It should be viewed as one part of a broader approach, not a replacement for movement or professional care.

Glucosamine is an amino sugar. Chondroitin sulphate is a sulphated glycosaminoglycan. They are different substances, and research results are not identical across all products and groups of people.

Joints and bones are not the same. Bones are living tissue that continuously remodels throughout life and responds to mechanical loading.

Bone-health care and osteoporosis prevention become increasingly important with age.

Inflammatory processes may be present in osteoarthritis, but this does not mean that every painful joint is caused by “chronic inflammation throughout the body”.

A markedly swollen, red or hot joint—especially with fever or sudden severe pain—requires professional assessment.

Photobiomodulation (PBM) applies red or near-infrared light to a selected area. Its use is studied in relation to pain, recovery of certain soft tissues and selected musculoskeletal problems.

PBM does not replace an appropriate movement programme. Outcomes depend on wavelength, dose, power, application time, treated area and other parameters; findings cannot be transferred automatically to every light device.

Hyaluronic acid is naturally present in synovial fluid. In selected patients, a clinician may administer it directly into the joint space.

An injection is not a permanent replacement for articular cartilage. A doctor decides whether intra-articular treatment is suitable for the individual patient.

The musculoskeletal system adapts gradually. Strength, coordination, function and load tolerance do not change overnight.

When should joint pain be assessed by a doctor?

Seek professional advice for marked swelling, a red or hot joint, fever, injury, inability to bear weight, sudden severe pain, unexplained severe night pain or rapidly worsening symptoms.

🦴 What should you remember?

Healthy movement depends on a connected system—not cartilage alone.