Patellofemoral pain syndrome

Anatomy: How the kneecap guides

The patella (kneecap) slides in a groove in the femur (trochlea femoris). When the knee is flexed and extended, the contact between the patella and thigh increases and the kneecap is centered via tendons, ligaments and the surrounding muscles. The quadriceps muscle (at the front of the thigh), the lateral retinacula (ligament structures), the medial patellofemoral ligament (MPFL) and the hip and pelvic stabilizers are particularly important.

• Patellar slide: bony groove (trochlea) as a “rail”
• Quadriceps and patellar tendons: power transmission for stretching movements
• Retinacula/MPFL: fine guiding structures for patellar centering
• Hip abductors/external rotators: stabilize the pelvis and leg axis

Harmonious guidance depends on the leg axis, muscle balance, soft tissue tension and training load. If there are imbalances, the pressure on parts of the kneecap increases - front knee pain can arise.

What is Patellofemoral Pain Syndrome?

Patellofemoral pain syndrome is a functional complaint in which pain occurs around or behind the kneecap when exerted. Unlike clear structural damage (e.g. cracks), PFSS often involves overloading, muscular imbalances and poor leg axis control. The term is not synonymous with “chondromalacia”; Softening of the cartilage can occur, but is not mandatory.

• Typical triggers: increasing training, lots of stairs/downhill, sitting for long periods of time
• Common in running and jumping sports, but also in everyday life
• Rarely the result of an accident - rather a gradual onset

Typical symptoms

• Dull, front knee pain around/behind the kneecap
• Reinforcement when climbing stairs (especially downhill), squatting, squatting, standing up
• “Cinema sign”: Pain or stiffness after sitting for a long time
• Occasional rubbing/grinding (crepitation) without compelling significance
• Rarely visible swelling; More pain from exertion than at rest

Warning signs that should be examined by a doctor are acute trauma with significant swelling, a feeling of blockage, fever, pain at night when resting or sudden, severe pain.

Causes and risk factors

It is usually a multifactorial event. It is not a single “mistake”, but the interaction of stress, technique, muscle function and anatomical conditions that leads to complaints.

• Overload: too rapid increase in volume/intensity, hard surfaces
• Muscular imbalances: weaker hip abductors/external rotators, quadriceps deficits
• Leg axis deviations: valgus position, increased inward rotation of the thigh
• Foot factors: pronounced pronation movement, fatigue of the foot muscles
• Soft tissue tension: shortened lateral structures (e.g. iliotibial tract)
• Anatomical variants: Patella alta, trochlear dysplasia (cause discomfort, especially when unstable)
• Training/shoes: unsuitable footwear, technical errors, little regeneration

Adolescents and young adults are often affected because growth, sport and periods of sitting come together. A quick return to work after a break from sports can also increase the risk.

Diagnostics: careful but targeted

Diagnosis is based primarily on history and physical examination. We pay attention to pain provocation during functional tests, axis control and muscle balance. Imaging is used specifically to exclude relevant differential diagnoses or to assess accompanying factors.

• Anamnesis: course, triggering activities, training changes, previous illnesses
• Clinical: step-down test, squats, single-leg stance, patellar slide/tilt assessment, J-sign
• Function: Hip abductor/external rotator strength, quadriceps, hip/ankle mobility
• Imaging: X-ray (lateral/axial) if the position is unclear or a malposition is suspected; MRI in case of resistance to therapy or suspected cartilage/soft tissue involvement
• Differential diagnoses: patellar tendon irritation, plica syndrome, meniscus pathology, Osgood-Schlatter/Sinding-Larsen-Johansson, patellar instability

Not everyone with front knee pain needs an MRI immediately. What matters is whether the findings change management. We will discuss with you transparently which examinations make sense.

Conservative therapy: the core of treatment

In most cases, patellofemoral pain syndrome can be easily treated without surgery. The focus is on education, load control and a structured exercise program for the hips, trunk and knees - supplemented by short-term measures to relieve pain.

Manual techniques and fascia treatments can be used alongside, but do not replace active training. Injections (e.g. cortisone, hyaluronic acid, PRP) have no proven routine indication for pure PFSS. If considered at all, then only after careful indication review and explanation.

Exercises to do at home: start safely and effectively

Start with low-pain exercises and increase slowly. Quality over quantity. Mild muscle irritation is desirable, persistent knee pain is not.

• Side plank with hip abduction (clamshells): 2-3 sets of 12-15 reps per side
• Side steps with mini band (knees slightly bent): 2-3 x 10-15 m
• Wall sit in moderate flexion (30–45°): 3 x 20–45 s, low pain
• Straight leg raise: 3 x 12-15 reps.
• Low level eccentric step-downs: 3 x 8-12 reps, good axis control
• Quadriceps/calf/hip flexor stretch: 3 x 20–30 s each

Only increase when the current level is well tolerated. As the exercise progresses, more difficult stimuli (e.g. squats, lunges, jumping variations) are possible - always with attention to a stable leg axis.

Back to sport: criteria instead of calendars

The return depends less on time and more on criteria: low pain in everyday life, good strength values ​​and controlled movement sequences. For runners, small adjustments to technique often help significantly.

• Running technique: Increase step frequency slightly (e.g. +5–10%), soft attachment
• Volume/Intensity: 10-15% increase per week as a rough guideline
• Vary the surface, initially reduce downhill
• Shoe check according to running style and wear

When is an operation an issue?

Surgery is rarely necessary for patellofemoral pain syndrome. It only comes into consideration if a structured conservative program consistently implemented over months does not bring sufficient improvement and there are clear structural causes.

• Marked maltracking with instability/episodes of patellar dislocation
• Significant anatomical factors (e.g. patella alta, trochlear dysplasia) with failure of conservative therapy
• Accompanying circumscribed cartilage damage that must be specifically addressed

Procedures such as isolated lateral release operations are now used very cautiously and only in selected situations. If instability is proven, ligament reconstruction (e.g. MPFL) or – depending on the findings – correction of the tibial tuberosity can be discussed. We advise you on this individually and based on evidence.

Prognosis and course

With consistent, well-guided conservative therapy, most cases improve within weeks to a few months. Individual activities can also remain sensitive for longer if peak loads are not adjusted. Patience, regularity and realistic goals are important.

• Early improvement often after 4-6 weeks
• More stable resilience after 8-12 weeks of structured training
• Recurrences are possible - can often be avoided through technique and strength training

Prevention: what you can do yourself

• Increase the load slowly and systematically, build in recovery phases
• Regular strength and stability training for the hips, core and quadriceps
• Technical training in running and jumping sports
• Check footwear and, if necessary, insoles regularly
• Design the workplace ergonomically; Interrupt sitting times

Your orthopedics in Hamburg-Winterhude

In our orthopedic specialist practice at Dorotheenstrasse 48, 22301 Hamburg, we provide you with structured and individual support - with a focus on conservative, active concepts. We take the time to provide diagnostics, understandable information and a treatment plan that fits your everyday life.

• Individual exercise programs and progress monitoring
• Interdisciplinary collaboration with physiotherapy
• Targeted imaging only if the question is clear
• Transparent indication for further measures

We would be happy to clarify your questions in an appointment, examine risk factors such as patellar maltracking and discuss sensible steps - from short-term relief to long-term stress relief.

Differentiation from instability and dislocation

Not all anterior knee pain is associated with instability. However, if dislocations (luxations) of the kneecap occur or significant maltracking occurs, other priorities in diagnosis and therapy apply. You can find relevant information on our pages on patellar luxation and patellar maltracking.

When you should see a doctor as soon as possible

• Acute accident with rapid swelling/blockage feeling
• Persistent nighttime pain at rest, fever, redness
• Repeated buckling events or dislocations of the kneecap
• No improvement despite 6-8 weeks of structured measures