Anterior Knee Pain

As the name suggests, in both conditions pain is felt in the anterior knee. With PFJ pain, the pain is poorly localised around the kneecap; it is typically aggravated by squatting, running downhill and descending stairs. There may be some associated crepitus reported by the patient or reproducible on examination. An axial (compressive) load through the patellofemoral joint will often provoke symptoms, though the diagnostic value of this is debated.Sources: Overview: Patellofemoral pain syndrome (runner’s knee) – InformedHealth.org – NCBI Bookshelf (opens in a new tab); The diagnostic value of the Clarke sign in assessing chondromalacia patella – PubMed (opens in a new tab)

With patella tendinopathy there are often key differences both subjectively and objectively. Pain from the patella tendon is normally quite accurately isolated. Symptoms are usually localised to the inferior pole of the patella or, less commonly, at the insertion onto the tibial tuberosity. Palpation of these bony landmarks often provokes symptoms. Patients typically describe activity-related anterior knee pain that is worse initially on starting activity, eases as sessions develop, only to return following cessation. As the disease progresses, symptoms often become more persistent even at rest.Source: Patellar tendinopathy: an overview of prevalence, risk factors, screening, diagnosis, treatment and prevention – PMC (opens in a new tab)

The diagnosis will be made from a combination of your clinical history and examination findings and, in certain cases, confirmed with imaging.

In the main part, PFJ pain and patella tendinosis are both clinical diagnoses, meaning if you have typical symptoms, imaging is not initially required. It is important to remember that for the majority of PFJ pain, there are no radiographic causes evident. However, for symptoms that are refractory to initial management, plain film X-rays can assess for any evidence of arthrosis in the patellofemoral joint. They can also assess the alignment of the patella and the morphology of the trochlear groove to check these articulations have good congruency.Source: Radiologic Assessment of Patellofemoral Pain in the Athlete – PMC (opens in a new tab)

Ultrasound can be helpful at viewing the patella tendon, seeing the severity of tendinopathy, as well as excluding other potential causes of patella tendon pain, including tendon tears and bursitis, though imaging often demonstrates a combination of these pathological changes. It has advantages over MRI given its dynamic capabilities and higher spatial resolution, making it often the first-line imaging modality to assess for pathology of the extensor tendon.Source: Musculoskeletal Ultrasound: An Essential Tool in Diagnosing Patellar Tendon Injuries – PMC (opens in a new tab)

MRI has the advantage of assessing both the PFJ and patella tendon. It is the imaging of choice in traumatic cases of patellofemoral dislocation or subluxation to assess for osteochondral injuries and disruption to the medial patellofemoral ligament, helping guide surgical management.Source: Radiologic Assessment of Patellofemoral Pain in the Athlete – PMC (opens in a new tab)

Treatment options are divided into conservative and surgical.

Conservative options

• Physiotherapy is the gold standard treatment and the first-line management in both cases. They will be able to address any biomechanical issues that may be contributing to your PFJ symptoms. For patella tendon pain, the aim of physiotherapy is to improve the tolerance and capacity of the extensor compartment of the knee through a graded and progressive rehab plan.Sources: Effectiveness of therapeutic physical exercise in the treatment of patellofemoral pain syndrome: a systematic review – PMC (opens in a new tab); Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial – PubMed (opens in a new tab)
• For refractory cases that are struggling to progress with rehab, ultrasound-guided ‘high volume’ injections can be utilised in the management of patella tendinopathy. This process involves injecting local anaesthetic, saline and a small amount of steroid into the interface between the patella tendon and Hoffa’s fat pad to mechanically disrupt neovascularisation (new blood vessels) and nerve ingrowth. These changes can be visualised on ultrasound and targeted dynamically.Source: High-Volume Image-Guided Injection for Recalcitrant Patellar Tendinopathy in Athletes – PubMed (opens in a new tab)
• PRP injections. A further injectable option for patients with patella tendinopathy +/- associated small tears is a PRP injection into the tendon itself under ultrasound guidance. The aim is to promote healing and reduce inflammation allowing better compliance with rehab. Its efficacy remains in debate as there remains no clear consensus on optimal dose and number of injections required to enhance its efficacy, but it has been shown to be beneficial in carefully selected patients.Sources: Platelet-rich plasma for jumper’s knee: a comprehensive review of efficacy, protocols, and future directions – PubMed (opens in a new tab); Platelet-rich plasma for patellar tendinopathy: a randomised controlled trial correlating clinical outcomes and quantitative imaging – PubMed (opens in a new tab)
• For patients with PFJ pain that are refractory to initial management, a hyaluronic acid injection may be beneficial. There is typically a better response in patients with degenerative change in their PFJ. Steroid injections in this cohort of patients can also be helpful at breaking a repeating pain cycle, allowing better compliance with rehab.Source: The role of viscosupplementation in patellar chondropathy – PMC (opens in a new tab)

Surgical options

For patellar tendinopathy, surgical input is typically the last resort, saved for those with severe and refractory symptoms despite extensive conservative management.

• There are both arthroscopic and open techniques to address the tendon itself. Debridement (removing damaged tissue) is the most common surgical option. Bone or tendon resection at the inferior patella pole and tendon repair are also options depending on the exact cause of your symptoms. The efficacy of surgical management for patella tendinopathy is generally unclear but has been shown to be beneficial in patients that have failed conservative options, allowing a high return to play.Source: A Systematic Review of Surgical Treatment for Refractory Patellar Tendinopathy – PMC (opens in a new tab)

For patients with isolated PFJ pain that is refractory to conservative management or for patients with repeated patella dislocations, surgery is aimed at addressing the underlying aetiology.

• Surgical treatment for PFJ arthrosis is achieved with either PFJ or a full knee arthroplasty. For recurrent dislocations, surgery may include a repair of the medial patellofemoral ligament, lateral release and/or trochleoplasty.Sources: Should we recommend patellofemoral arthroplasties to patients? a systematic review – PMC (opens in a new tab); Medial Patellofemoral Reconstruction Techniques for Patellar Instability – PubMed (opens in a new tab)