Patellofemoral Pain and Patellar Instability (Kneecap Problems) in Bristol & Bath

Patellofemoral pain is pain felt around or behind the kneecap (patella), often worse on stairs, hills, squats, running, or after sitting with the knee bent. Patellar instability means the kneecap partially slips out of place (subluxation) or fully dislocates. These problems can overlap: a knee can be painful without dislocating, and instability can also cause pain, swelling, and loss of confidence.

Mr Simon Abram, Consultant Specialist Knee Surgeon, provides specialist assessment and treatment planning for patellofemoral pain and kneecap instability in Bath and Bristol. The best treatment depends on the cause, and in many cases, success comes from treating the whole patellofemoral 'system' rather than one structure alone.

What does the kneecap do?

The kneecap (patella) sits in a groove at the front of the thigh bone (the trochlea). It acts like a pulley for the quadriceps muscle, improving the efficiency of straightening the knee. The undersurface of the kneecap and the groove are lined with cartilage to allow smooth movement.

What is patellofemoral pain?

Patellofemoral pain describes pain generated from the front of the knee, usually related to overload or irritation in the kneecap joint. It can be caused by training errors, muscle weakness, poor movement control, tightness, overuse, cartilage wear, or subtle alignment issues. It does not automatically mean arthritis or “damage,” and many people improve with the right rehabilitation.

What is patellar instability?

Patellar instability occurs when the kneecap does not stay centred in the groove during movement. It can range from:

Subluxation: the kneecap partially shifts out of place then slides back
Dislocation: the kneecap fully comes out of the groove and usually needs to be relocated

Instability may happen after a single traumatic event, or recur due to underlying anatomy (such as a shallow groove, malalignment, or high-riding kneecap).

Common causes and contributing factors

Patellofemoral pain and instability are often multifactorial. Key contributors can include:

Muscle weakness or poor control (hip, gluteal, and quadriceps control affecting kneecap tracking)
Overuse / training load (rapid increases in running, hills, stairs, squats)
Patella alta (a high-riding kneecap)
Trochlear dysplasia (a shallow or misshapen groove)
Increased TT–TG distance (the tendon line of pull sits too far to the outside, encouraging lateral tracking)
Rotational alignment issues (femoral anteversion, tibial torsion)
Valgus alignment (knock-knee) or other alignment patterns affecting the joint line
Ligament injury, especially of the MPFL after a dislocation
Fat pad impingement (pinching and inflammation of the soft tissue below the kneecap)

Symptoms

Patellofemoral pain symptoms

Pain behind/around the kneecap, often worse with stairs, hills, squatting, lunging, running, or prolonged sitting
Grinding or creaking sensations (sometimes)
Swelling after activity (sometimes)
Tenderness at the front of the knee

Patellar instability symptoms

A feeling the kneecap “shifts,” “slips,” or is about to dislocate
Giving-way episodes with twisting or sudden direction changes
Swelling after an event, often rapidly if a true dislocation occurs
Apprehension or fear with certain positions (for example when the knee is bent and the kneecap is pushed sideways)

Fat pad impingement symptoms

Sharp or aching pain at the front of the knee, often just below the kneecap
Pain when fully straightening the knee or standing with the knee “locked back”
Localised tenderness and swelling at the front of the joint

Assessment and diagnosis (Bath & Bristol)

Getting kneecap problems right requires identifying which factor is driving symptoms: overload, tracking, instability, anatomy, or a combination. Mr Simon Abram offers specialist patellofemoral assessment in Bristol and Bath, including instability risk profiling and alignment analysis.

Assessment usually includes:

History: dislocation events, pain triggers, swelling pattern, sport/work demands, previous treatments
Examination: kneecap tracking, tenderness, stability, range of motion, hip control, and movement quality
X-rays: to assess patella position, joint surfaces, and alignment
MRI scan: to assess cartilage, MPFL injury, bone bruising, and fat pad inflammation
CT or specialist imaging (selected cases): to quantify alignment measures and rotational profile

The goal is a diagnosis that explains the symptoms and supports a plan that is predictable and durable.

First-line treatment: physiotherapy and load management

For many people, the most effective first step is a structured rehabilitation programme. This is particularly true for patellofemoral pain without recurrent dislocation.

Physiotherapy focus

Hip and glute strength (improves limb control and reduces kneecap overload)
Quadriceps strength (especially functional control through range)
Movement retraining (squat/step/running mechanics)
Flexibility and soft tissue control where relevant
Load progression (gradual return to hills, stairs, and running)

Other non-surgical options (selected cases)

Taping or bracing for symptom control
Short-term anti-inflammatory medication if appropriate
Activity modification to calm flare-ups
Targeted injections in selected cases (used cautiously and only when appropriate)

If symptoms persist, or if there is true recurrent instability, surgical options may be considered based on the underlying anatomy.

Understanding key terms (what they mean)

Patella alta (high-riding kneecap)

Patella alta means the kneecap sits higher than usual. This can reduce the time the kneecap is engaged within the groove during early bending, increasing the risk of instability and sometimes contributing to pain. It can be:

Static patella alta: the kneecap sits high on imaging even at rest
Dynamic patella alta: the kneecap is higher when loaded and this impact on the movement and engagement of the knee joint when it begins to bend from a straightened position.

TT–TG distance

The TT–TG distance describes how far the patellar tendon attachment sits from the centre of the groove. If it is relatively lateral, the line of pull can encourage the kneecap to track outward, contributing to instability. Whilst TT-TG has traditionally been one of the primary measures in patella instability, the latest evidence suggests it is less relevant and can be misleading - especially in the context of dysplasia, alta, and rotational problems in the limb (torsion).

Trochlear dysplasia

Trochlear dysplasia means the groove the kneecap should sit in is shallow or misshapen, reducing stability–particularly in early knee flexion.

Rotational alignment (torsion)

Rotational alignment refers to twist in the thigh bone (femur) or shin bone (tibia). Excess femoral anteversion or tibial torsion can change how the kneecap tracks and increase lateral forces.

Surgical options: stabilisation and realignment

Surgery is tailored to the cause. Some patients need soft-tissue stabilisation and 'balancing', some need bony realignment, and some need a combined approach.

MPFL reconstruction (kneecap stabilisation)

The medial patellofemoral ligament (MPFL) is the main soft-tissue restraint preventing the kneecap from dislocating laterally in early knee bending. It is commonly injured in a dislocation.

MPFL reconstruction rebuilds this restraint, usually using a tendon graft, to reduce the risk of recurrent dislocation. It is most commonly considered for:

Recurrent patellar instability (repeated subluxations/dislocations)
Persistent instability symptoms with an anatomical risk profile
Selected first-time dislocations when there is high risk of recurrence or associated injury

MPFL reconstruction can be performed alone in some patients, but if major bony risk factors are present (such as patella alta or significant malalignment), combining procedures may be more predictable.

Osteotomy and bony realignment options (when mechanics drive the problem)

Osteotomy means reshaping bone to change alignment and load. In patellofemoral problems, osteotomy is considered when alignment, patella height, or rotational profile is a major driver of pain or instability.

Tibial Tubercle Osteotomy (TTO)

A tibial tubercle osteotomy repositions the bony attachment of the patellar tendon. This can change kneecap tracking, reduce lateral pull, and in some cases lower a high-riding kneecap.

TTO may be considered when:

There is patella alta that contributes to instability (static and selected dynamic cases)
There is a lateralised tendon line of pull contributing to maltracking/instability
There is focal cartilage wear where unloading a specific area may help

In simple terms, TTO can help the kneecap engage the groove earlier, track more centrally, and reduce overload in selected areas.

Distal Femoral Osteotomy (DFO)

A distal femoral osteotomy corrects alignment at the lower thigh bone. It is most relevant when knock-knee alignment (valgus) increases lateral forces across the knee and can worsen patellofemoral symptoms or contribute to instability patterns.

DFO may be considered when:

Valgus (knock-knee) alignment is a key driver of symptoms
There is lateral compartment or lateral patellofemoral overload linked to alignment

High Tibial Osteotomy (HTO)

A high tibial osteotomy corrects alignment at the upper shin bone. It is most often used for bow-leg alignment (varus) with medial compartment overload, but it can also be relevant in broader knee-preservation planning when overall limb mechanics contribute to symptoms.

HTO may be considered when:

Varus (bow-leg) alignment is contributing to overload elsewhere in the knee
Knee mechanics need rebalancing as part of a combined preservation strategy

Rotational osteotomy (torsional correction)

A rotational osteotomy corrects abnormal twist in the femur or tibia. It is considered when rotational alignment is a major driver of maltracking or instability and symptoms persist despite excellent rehabilitation.

Rotational osteotomy may be considered when:

There is significant femoral anteversion or tibial torsion contributing to lateral tracking forces
Instability persists and the rotational profile strongly supports torsion as a driver

Rotational correction is a major decision and is reserved for carefully selected cases where imaging and symptoms strongly align.

Trochleoplasty (improving the groove) for selected instability cases

Trochleoplasty reshapes the trochlear groove to improve kneecap containment. It is not a routine procedure for patellofemoral pain alone. It is typically considered for recurrent patellar instability where there is significant trochlear dysplasia and the groove shape is a key reason the kneecap dislocates.

In selected patients, trochleoplasty may be combined with procedures such as MPFL reconstruction and/or tibial tubercle osteotomy to address multiple risk factors.

Fat pad impingement: what it is and how it’s treated

The infrapatellar fat pad is a sensitive soft tissue structure beneath the kneecap. If it becomes inflamed or pinched (impinged), it can cause sharp anterior knee pain, especially when fully straightening the knee or standing with the knee locked back.

Treatment often includes:

Physiotherapy to improve movement control and reduce pinching positions
Load modification and activity pacing
Anti-inflammatory strategies when appropriate
In selected cases, targeted injection or arthroscopic management may be discussed

Recovery and rehabilitation

Rehabilitation is essential in both non-surgical and surgical pathways. The plan depends on which procedure (or combination) is performed.

Typical aims of rehabilitation

Control swelling and restore movement
Rebuild strength (quadriceps, glutes, hips) and movement quality
Improve kneecap control and confidence in higher-demand tasks
Progressively return to running and sport when safe

Procedures such as MPFL reconstruction, TTO, trochleoplasty, or osteotomy have protective phases early on, followed by progressive strengthening and functional retraining. Your programme is individualised based on anatomy, healing, and goals.

Risks and limitations

All surgery carries risks. The exact risks depend on the procedure performed. Potential issues include:

Infection, blood clots, stiffness, or prolonged swelling
Ongoing pain or incomplete symptom improvement
Recurrent instability if underlying drivers are not fully addressed
Hardware irritation after bony procedures (such as TTO or osteotomy)
Cartilage wear progression over time in some knees

A personalised discussion in clinic will cover the expected benefits, alternatives, the likely rehabilitation course, and the risks most relevant to your knee.

Frequently asked questions

What’s the difference between patellofemoral pain and patellar instability?

Patellofemoral pain is primarily pain from the kneecap joint, often related to overload and movement mechanics. Patellar instability is when the kneecap partially or fully slips out of position. Some people have both.

Do I always need surgery if I dislocate my kneecap?

Not always. Treatment depends on whether the dislocation is a first-time event or recurrent, whether there is associated cartilage injury, and whether your anatomy suggests a high risk of recurrence. Many people start with physiotherapy, but recurrent instability often needs surgical stabilisation. Mr Abram works closely with a specialist team of physiotherapists with expertise in the full scope of rehabilitation.

When would a tibial tubercle osteotomy (TTO) be considered?

TTO is considered when kneecap position and tendon mechanics are a key driver, especially with patella alta (static or selected dynamic cases), maltracking patterns, or instability risk factors. It is often used alongside ligament stabilisation procedures in appropriate patients.

What does MPFL reconstruction do?

MPFL reconstruction rebuilds a key ligament on the inner side of the knee that helps prevent the kneecap dislocating outward. It is commonly used for recurrent instability and can be combined with bony procedures when needed.

When is trochleoplasty used?

Trochleoplasty is typically reserved for recurrent instability when the groove shape (trochlear dysplasia) is a major driver. It is not usually performed for pain alone.

When is a knee brace needed?

A knee brace isn’t always needed for patellofemoral pain or kneecap instability, but it can help in specific situations by protecting healing tissues, supporting safer movement, and reducing re-injury risk while strength and control return. After a tibial tubercle osteotomy (TTO), a brace is commonly used in the early recovery phase–especially in the first 4–6 weeks–because pain and swelling can temporarily inhibit the quadriceps, making the knee feel like it may “give way” during weight-bearing; the brace provides added stability while physiotherapy rebuilds quadriceps control, and the amount of allowed knee bend and duration of bracing are tailored to your procedure and progress.

Can I be assessed for patellofemoral pain or kneecap instability in Bath or Bristol?

Yes. Mr Simon Abram offers specialist assessment and treatment planning for patellofemoral pain and patellar instability in Bath and Bristol, including physiotherapy-led care, imaging-based diagnosis, and surgical options when appropriate.

This information is general and does not replace personalised advice. Brace type, settings, and duration should be tailored to the procedure performed and your individual recovery.