Patella chondropathy

Anatomy and function of the patellofemoral joint

When the knee is bent and extended, the kneecap (patella) slides in a groove on the thigh bone (trochlea femoris). Their back is covered with smooth hyaline cartilage, which reduces friction and distributes forces.

• Cartilage: acts like a shock absorber, but has limited regenerative ability
• Quadriceps tendon and patellar tendon: control the guidance of the patella
• Tendon and ligament structures (e.g. lateral retinaculum, medial patellofemoral ligament): stabilize laterally
• Leg axis and foot position: influence the direction of pull on the patella

If there is overloading, misalignment or repeated microtrauma, the cartilage can soften or wear out in places. These changes are called chondropathia (often also chondromalacia) patellae.

What is patellar chondropathy?

Patella chondropathy is an umbrella term for degenerative or overload-related cartilage changes on the back surface of the kneecap. It often occurs in people who are active in sports, but also in those who are sedentary. Typical is the anterior, often dull pain behind or around the kneecap, occasionally accompanied by rubbing, clicking or a feeling of tension. The symptoms depend on the load and can be unilateral or bilateral.

Important: Not every cartilage change means osteoarthritis. Early stages are often reversible in terms of symptoms if triggers are identified and treated. If left untreated, the risk of patellofemoral osteoarthritis can increase.

Typical symptoms

• Anterior knee pain, aggravated when climbing stairs (especially downwards), squatting or rising from a sitting position
• Pain after sitting for a long time with a bent knee (“cinema or theater seat”)
• Tenderness behind the kneecap, occasionally rubbing or crackling
• Stress-related swelling or effusion
• Feeling of instability or slipping, without real dislocation

Causes and risk factors

Patella chondropathy is usually multifactorial. Repeated overloading and suboptimal positioning of the kneecap often come together.

• Overload: rapid increase in training, running downhill, jumping sports, a lot of squatting
• Muscle imbalance: weak quadriceps (especially medial parts), weak hip abductors/external rotators, shortened hamstrings and iliotibial band
• Misalignments: knock-knee tendency (valgus), patella alta (high kneecap), torsion variations, increased foot pronation
• Anatomical variants: flat slide (trochlear dysplasia), bony prominences or plicae
• Trauma or microtrauma: impact, repeated kneeling
• Other factors: obesity, joint hypermobility, previous patellar instability

Diagnostics: This is how we proceed

It starts with a detailed anamnesis: When does the pain occur, which sports and everyday stresses are relevant, was there a trauma? This is followed by a structured clinical examination.

• Inspection of the leg axis and gait analysis
• Functional tests: Single-leg squat, assessment of patellar sliding and tilting, pain provocation with pressure or compression
• Muscle function diagnostics: quadriceps, gluteal muscles, extensibility of lateral structures
• Assessment of possible swelling/effusion as a sign of synovitis

Imaging is used specifically if the findings are unclear, the symptoms persist or structural damage is suspected.

• X-ray in several planes including a tangential image of the kneecap to assess the position and height of the patella
• MRI to show cartilage, bone edema, synovitis and accompanying pathologies
• Sonography to assess effusion and soft tissue (supplementary)

It is important to distinguish it from other causes of anterior knee pain, e.g. B. Plica syndrome, patellar tendinopathy, loose joint bodies, osteochondrosis dissecans or early patellofemoral arthrosis.

Conservative therapy: The standard approach

Most patients benefit from structured, multimodal conservative treatment. The aim is to reduce pain, improve kneecap guidance and slowly increase resilience.

Typically, the first stable improvements are achieved after 6-12 weeks, provided a consistent exercise program is carried out. The pace depends on the pain and stimulus; “No-pain-no-gain” is not effective.

Infiltrations and regenerative options

If the irritation persists or if conservative measures alone are not sufficient, infiltrations can be considered. We discuss opportunities and limitations individually; there is no guarantee of success.

• Hyaluronic acid (viscosupplementation): can improve lubrication and reduce pain, especially. a. with accompanying patellofemoral arthrosis; Effectiveness varies
• PRP (platelet-rich plasma): option for anterior knee pain and localized cartilage irritation; Evidence is growing but is heterogeneous
• Corticosteroids: can reduce inflammation in the short term; only cautiously and specifically because of possible side effects and cartilage toxic effects

Regenerative interventions aim to alleviate symptoms and gain function. They do not replace active therapy and are always combined with exercise and stress programs.

When does an operation make sense?

Surgical measures can be considered if there is no sufficient improvement after several months of conservative therapy according to the guidelines and there are structural causes relevant to imaging. The procedure depends on the size of the defect, location and accompanying factors (e.g. incorrect guidance).

• Arthroscopic smoothing/chondroplasty for frayed surface cartilage to reduce mechanical irritation
• Cartilage repair procedures for localized defects: depending on the situation, e.g. B. Microfracture, osteochondral transfer (OATS) or autologous chondrocyte transplantation
• Soft tissue balancing: selective lateral retinaculum release only if lateral tightness and tilting are proven
• Corrective osteotomy of the tibial tuberosity (e.g. anteromedializing transfer) to relieve pressure and center the patella
• Additional procedure for instability: reconstruction of the medial patellofemoral ligament

Surgical decisions are made individually and after careful information. An operation does not guarantee a complete resolution of the symptoms, but if the indication is appropriate it can create the conditions for better function.

Course, prognosis and return to sport

The majority of cases improve with structured conservative therapy. What is crucial is the adjustment of the load, a patient training structure and the treatment of favorable factors (e.g. axle control, footwear, weight).

• Time course: first improvements often after 6-12 weeks, stabilization over several months
• Return to sport: gradual, adapted to pain and stimuli; Slowly increase the scope and intensity of training
• Risk factors for relapses: loading too quickly, unchanged technique errors, untreated axis problems

Self-help: exercises and everyday tips

• Strengthening 3 times a week: straight leg extension, mini-squats in the low-pain area, step-ups, hip abduction and external rotation with mini band
• Stretching: quadriceps, hamstrings, calves, IT band gently and regularly
• Everyday life: frequent changes in position instead of sitting for long periods with strongly bent knees; Adjust the saddle slightly higher when cycling
• Stairs: conscious, axis-correct descent; Use handrail, increase step frequency
• Training diary: Document stress and symptoms to recognize patterns

Differentiation from other causes of anterior knee pain

• Plica mediopatellaris syndrome: wrinkled mucous membrane irritates the plain bearing
• Patellar tendinopathy: tenderness on the patellar tendon
• Osteochondrosis dissecans: circumscribed bone-cartilage lesion, often with pain on exertion and possibly blockages
• Free joint bodies or pronounced synovitis/irritable effusion
• Patellofemoral osteoarthritis: advanced cartilage wear with stress-dependent pain and starting pain

When should I seek medical advice?

• Acute accident with significant swelling, feeling of blockage or instability
• Severe joint effusion, redness, overheating, fever
• Persistent pain despite consistent protection and basic therapy over several weeks
• Recurring “kinks” or suspected dislocation of the kneecap

Our treatment approach in Hamburg

In our orthopedic practice at Dorotheenstrasse 48, 22301 Hamburg, we value precise diagnostics and conservative, function-oriented therapy. We will work with you to develop an individual plan consisting of physiotherapy, technology and everyday coaching. We only discuss regenerative and surgical procedures if there is a clear indication and after a transparent risk-benefit assessment.