From the Guidelines
Common knee replacement problems approximately one year after implantation include persistent pain, stiffness, instability, and infection, with infection being a serious complication reported in 0.8% to 1.9% of total knee arthroplasties (TKAs) 1. These complications can significantly impact the patient's quality of life, morbidity, and mortality.
- Persistent pain affects about 10-20% of patients and may result from implant loosening, component malposition, or soft tissue irritation.
- Stiffness limiting range of motion can occur due to scar tissue formation (arthrofibrosis) and may require physical therapy focusing on stretching and strengthening exercises, typically 3-5 sessions weekly for 6-8 weeks.
- Instability may manifest as a feeling that the knee is giving way or not properly supporting weight, often requiring evaluation by the orthopedic surgeon.
- Infection presents with increased pain, warmth, redness, and swelling, requiring immediate medical attention and possibly antibiotics like cefazolin (1-2g IV every 8 hours) or vancomycin for MRSA concerns, as supported by the American Academy of Orthopaedic Surgeons (AAOS) guidelines 1. Other potential issues include implant loosening, which may cause pain during weight-bearing activities, and periprosthetic fractures. Regular follow-up appointments with the orthopedic surgeon are essential, typically scheduled at one year post-surgery, to detect and address these complications early 1. Most complications can be effectively managed with appropriate intervention, and patients should report any new or worsening symptoms promptly rather than assuming they are normal parts of recovery. The use of serologic tests such as ESR, CRP, and serum interleukin-6 testing can help diagnose infection, as recommended by the AAOS guidelines 1. Additionally, imaging studies like 3-phase bone scans can be useful in detecting loosening and infection, but may have limitations in distinguishing between the two 1. Overall, a comprehensive approach to diagnosing and managing knee replacement complications is crucial to optimizing patient outcomes and improving quality of life.
From the Research
Common Knee Replacement Problems
Approximately one year after implantation, common knee replacement problems include:
- Stiffness, which can be defined as >15° flexion contracture and/or flexion <75° or a range of motion less than the patient needs to perform daily activities 2
- Limited range of motion, with a minimum of 90 degrees required for normal activities of daily living 3
- Increased symptoms of stiffness, which can be associated with a worse functional outcome and lower rate of patient satisfaction 4
Risk Factors for Stiffness
Risk factors for stiffness after total knee arthroplasty include:
- Preoperative risk factors such as limited range of motion, underlying diagnosis, and history of prior surgery 5
- Intraoperative factors such as improper flexion-extension gap balancing, oversizing or malpositioning of components, and inadequate resection of posterior osteophytes 5
- Postoperative factors such as poor patient motivation, arthrofibrosis, infection, complex regional pain syndrome, and heterotopic ossification 5
- Male gender, lung disease, diabetes, back pain, and a pre-operative stiffness score of 44 or more 4
Treatment Options
Treatment options for stiffness after total knee arthroplasty include:
- Mobilization and physical therapy 5, 6
- Manipulation under anesthesia, which can be effective for flexion contracture within the first 3 months after surgery 5, 2
- Arthrolysis, which can be arthroscopic or open, and may be indicated if there is no significant technical error 2
- Implant revision, which may be necessary in cases of malpositioning or oversizing, but carries a high risk of complications 2