What is Patellofemoral Pain Syndrome (PFPS) and why is it important? PFPS also referred to as chondromalacia of the patella, is a common knee problem that is most prevalent in youth and female athletes. Chondromalacia is a general term indicating damage to the cartilage under your kneecap (patella). Patellofemoral disorders are often some of the most common anterior knee pain disorders in the orthopedic and sports medicine setting often including the patella and surrounding retinaculum. Individuals with PFPS commonly have intrinsic anatomical factors and extrinsic external findings that can cave a large role in the pathophysiology. Although the exact etiology is debated, some of the factors include: overuse, muscle imbalance, soft tissue restrictions, and structural alignment such as increased Q angle. Patellofemoral Pain Syndrome can be broken down into eight groups as described by Dr. George Davies: 1) patellar instabilities, 2) biomechanical dysfunctions such as Lateral Pressure Syndrome, 3) patellar compression syndromes, 4) soft tissue lesions, 5) direct patellar trauma, 6) overuse syndromes, 7) osteochondritis diseases and 8) neurological diseases.
How is PFPS diagnosed? PFPS is a multifactorial clinical diagnosis made from the identification of the origin of symptoms, direct limitations and possibly appropriate imaging techniques.
The biomechanical evaluation of PFPS can consist of movement analysis for squatting, jumping, stepping, and other special tests. Functional movement tests such as the SFMA and FMS can be very valuable tools for movement analysis. Additionally, static observations and measurements of Q angles, foot posture, tibial and femoral rotations as well as patellar mobility may be considered.
What are the main structures that play a role in PFPS?
There are many muscles, tendons, ligaments, and tissues that form the knee and the structures above and below it. All of the components can contribute in some way to the development of a PFPS. Listed below are some of the most commonly involved structures.
The Femur is the bone on top of the knee joint. It has the trochanteric grove which the patella (knee cap) glides over and the trochanters which sit on top of the Tibial Plateau of the Tibia which is the bottom bone. These three bones comprise the boney structures of the knee.
The Iliotibial Band (ITB) is a dense band of connective tissue that begins at the hip and pelvis and ends at the tibia at a structure called Gerdy’s tubercle. Just above this tubercle the ITB fans out to connect to the patella as a structure called the lateral retinaculum. When tight, the lateral retinaculum will cause the patella to laterally tilt and cause abnormal pressure of the patella on the femur. This can be a cause of PFPS and chondromalacia patella.
The Medial Retinaculum and lateral retinaculum are the kneecap (patella) has both a medial (inside aspect) and a lateral (outside aspect) retinaculum. These retinaculum structures help to provide support to the kneecap and position it in the center of the trochanteric notch. Weakness or tightness in these structures can contribute to chondromalacia and anterior knee pain.
The Quadriceps muscles (4 of them) insert to a common insertion called the quadriceps tendon that attaches to the patella. The patella then has a tendon Patella Tendon) that continues onto a structure on the tibia called the tibial tubercle. The quadriceps tendon and the patella tendon can have several abnormal positions and pathologies such at sitting too high (patella Alta) and sitting to low (patella baja). Weak quads or the over dominance of the quads can contribute to chondromalacia and anterior knee pain.
The medial plica of the knee is a well-vascularized thin, intra articular fold of the synovial tissue over the medial aspect of the knee. It originates at the genu articularis muscle (contracts to lift knee capsule out from under patella with extension of the knee), and crosses over the medial aspect of the medial femoral condyle to attach to the distomedial aspect of the intra articular synovial lining of the knee. In some patients, particularly those who may have had injuries or surgeries over the medial aspect of the knee, the medial plica can become thick and fibrotic and catch with flexion and extension of the knee.
Principals of PFPS rehabilitation.
Conservative management is an important first choice of treatment. Many options for conservative treatment include: exercise, patella taping and bracing, foot orthoses, manual therapy, electrotherapy, biofeedback and pharmacology. There is currently strong evidence for a multimodal physiotherapy approach targeting distal and proximal influences contributing to the cause of PFPS.
Excessive Lateral Pressure Syndrome:
– Low load long duration stretch of tight soft tissue structures (taping)
– Manual therapy to stretch tight lateral retinaculum with medial glides and tilts
– Flexibility exercises with emphasis on ITB stretching
– Strengthening exercises for quads and weak structures with appropriate PRE progression.
Global Patellar Pressure Syndrome:
– Emphasize patellar mobilization
– Knee ROM
– Flexibility exercises
– Strengthening exercises for quads and weak structures with appropriate PRE progression.
Patella Instability
– Taping and/or bracing of patella
– Address misalignment through stretching and appropriate orthotics
– Strengthening exercises for quads and weak structures with appropriate PRE progression.
– Activity modifications
Direct Patellar Trauma:
– Lower extremity flexibility
– Lower extremity Range of Motion
– Strengthening exercises for quads and weak structures with appropriate PRE progression.
Plica Soft Tissue Lesion:
– Decrease inflammation with modalities
– Cross Friction massage to reduce fibrotic scarring
– Address contributing factors such as muscle tightness, weakness and misalignment.
Infrapatellar Fat Pad Syndrome:
– Tape to unload fat pads
– Address misalignment through stretching and orthotics
– Strengthening exercises for quads and weak structures with appropriate PRE progression that is non painful and avoids terminal knee extension
– Phonophoresis/ lonto and cryotherapy
– Heel lifts