Overview
Pathological fractures of the patella are uncommon but significant injuries often associated with underlying bone pathologies such as osteoporosis, osteonecrosis, or metastatic disease. These fractures can also occur secondary to chronic patellar instability, repetitive stress injuries, or traumatic events, particularly in high-impact sports. Athletes, especially those involved in activities requiring repetitive knee flexion and extension like fencing or jumping sports, are at a heightened risk. Early recognition and appropriate management are crucial to prevent long-term functional impairment and to facilitate a return to pre-injury activity levels.
Clinical Presentation
Symptoms and Signs
Patients with a pathological fracture of the patella typically present with acute knee pain, often exacerbated by weight-bearing activities or specific movements that stress the patellofemoral joint. The pain may be localized to the anterior knee, radiating down the leg in severe cases. Swelling, tenderness over the patella, and an inability to fully extend or flex the knee are common physical findings. In athletes, such as the 31-year-old Olympic fencer described, additional symptoms may include instability, clicking or grinding sensations, and a noticeable decrease in performance quality [PMID:24825047].
Differential Diagnosis
Differentiating a pathological patellar fracture from other knee pathologies is essential. Conditions to consider include:
Meniscal Tears: Often coexist with patellar issues, especially in athletes with repetitive stress injuries.
Patellar Dislocation or Subluxation: Can mimic fracture symptoms, particularly if associated with trauma.
Osteoarthritis: Chronic degenerative changes can lead to patellar stress fractures in older patients.
Osteonecrosis: Particularly relevant in younger patients with risk factors like corticosteroid use.
Metastatic Disease: Important in older patients or those with a history of cancer, where bone involvement can weaken the patella.Diagnostic Workup
Radiographic Imaging: Initial X-rays are crucial for identifying fractures, but may not always show subtle changes. Advanced imaging such as CT scans can provide more detailed views of bone structures.
MRI: Essential for assessing soft tissue involvement, including meniscal damage and ligamentous integrity, as seen in the case of subtotal meniscal loss [PMID:24825047].
Bone Scan or PET Scan: Useful in identifying underlying bone pathologies like metastatic disease or osteonecrosis.Diagnosis
The diagnosis of a pathological patellar fracture involves integrating clinical symptoms with imaging findings. Key diagnostic criteria include:
Clinical History: Detailed history focusing on trauma, repetitive stress, underlying medical conditions, and athletic activities.
Physical Examination: Assessing for tenderness, swelling, range of motion limitations, and signs of instability.
Imaging Confirmation: Radiographic evidence of a fracture line, often corroborated by MRI findings that rule out or confirm associated soft tissue injuries.Management
Non-Surgical Management
Non-surgical approaches are generally reserved for less severe cases or as adjuncts to surgical interventions. These may include:
Immobilization: Use of a knee brace or cast to stabilize the knee and allow initial healing.
Pain Management: Analgesics such as NSAIDs to manage pain and reduce inflammation.
Physical Therapy: Gradual rehabilitation focusing on quadriceps strengthening and patellar tracking exercises to prevent future instability.Surgical Management
#### Indications for Surgery
Surgical intervention is often necessary for definitive treatment, especially in athletes requiring rapid return to high-level function. Indications include:
Complex Fractures: Those not amenable to conservative treatment.
Associated Injuries: Such as significant meniscal tears or ligamentous damage.
Chronic Instability: Persistent patellar maltracking or instability post-immobilization.#### Surgical Techniques
Biological Reconstruction: As seen in the case of the Olympic fencer, a biological approach involving lateral meniscal allograft transplantation and patellar realignment can address both structural and functional deficits [PMID:24825047]. This method aims to restore knee stability and function comprehensively.
Patellar Fixation: Techniques include press-fit versus cemented fixation. Press-fit implantation has shown advantages in reducing patellar maltracking, with a lower incidence of complications compared to cemented fixation (8% vs 30%) [PMID:11805920].#### Post-Surgical Care
Immobilization: Initial immobilization with a brace to protect the surgical site.
Rehabilitation: A structured rehabilitation program tailored to the patient’s activity level, typically starting with passive range of motion exercises and progressing to weight-bearing activities and strengthening exercises.
Monitoring: Regular follow-up visits to monitor healing progress, adjust rehabilitation protocols, and address any complications early.Complications
Potential Complications
Patellofemoral Complications: These include persistent pain, stiffness, and instability. In cemented patellar implants, complications such as maltracking and loosening occur in approximately 2.3% of cases, with revision surgery required in rare instances [PMID:11805920].
Infection: A risk associated with any surgical intervention, necessitating vigilant monitoring and prompt treatment if signs of infection arise.
Nonunion or Malunion: Potential issues with fracture healing, particularly in cases with underlying bone pathology.Prognosis & Follow-Up
Long-Term Outcomes
The prognosis for patients undergoing comprehensive surgical interventions, such as those described in the Olympic athlete case, can be favorable with appropriate rehabilitation. The athlete was able to resume competitive activities within 17 months post-surgery, highlighting the potential for a successful return to high-level performance [PMID:24825047]. However, individual outcomes can vary based on the severity of initial injury, underlying pathology, and adherence to rehabilitation protocols.
Follow-Up Schedule
Immediate Post-Op: Frequent visits (weekly to bi-weekly) to monitor healing and manage pain/swelling.
Early Rehabilitation Phase: Monthly visits to adjust rehabilitation plans and ensure proper progression.
Long-Term Monitoring: Every 6-12 months for the first two years, then annually to assess joint function, alignment, and overall knee health.Key Recommendations
Early Diagnosis and Intervention: Prompt recognition and appropriate management are critical for optimal outcomes.
Comprehensive Surgical Approaches: Consider biological reconstructions and precise fixation techniques to address both structural and functional issues.
Personalized Rehabilitation: Tailor rehabilitation programs to the patient’s specific needs and activity levels.
Regular Follow-Up: Maintain consistent monitoring to manage complications and ensure sustained recovery.By adhering to these guidelines, clinicians can effectively manage pathological patellar fractures, aiming to restore function and facilitate a safe return to athletic activities.
References
1 Perdisa F, Filardo G, Di Matteo B, Di Martino A, Marcacci M. Biological knee reconstruction: a case report of an Olympic athlete. European review for medical and pharmacological sciences 2014. link
2 Valdivia GG, Dunbar MJ, Jenkinson RJ, Macdonald SJ, Rorabeck CH, Bourne RB. Press-fit versus cemented all-polyethylene patellar component: midterm results. The Journal of arthroplasty 2002. link
2 papers cited of 3 indexed.