Total knee arthroplasty (TKA) is a successful and durable procedure for management of the painful arthritic knee. The literature demonstrates more than 90% survivorship at 20 years with a well-performed arthroplasty. As the number of annual primary TKAs performed each year increases exponentially, the number of revision TKAs also continues to grow despite improvements in implant design, biomaterials, and techniques. The increase in the revision TKA burden is especially seen within high-volume and tertiary referral arthroplasty centers. The modes of failure are variable, are influenced by a multitude of factors, and can result from instability, infection, component loosening or malposition, stiffness, periprosthetic fracture, component breakage, polyethylene wear, or osteolysis. When failure does occur and revision is contemplated, a very thorough history and physical examination, along with imaging studies and laboratory tests, are necessary. It is imperative that the preoperative evaluation identify the cause of failure to increase the likelihood of successful revision TKA. This chapter focuses on the history and physical examination of patients with painful TKA. Imaging of the painful TKA is covered in Chapter 4 and the laboratory tests in Chapter 3 .
A thorough history should be conducted to determine the cause of the painful or failed TKA. Relevant information should focus on the knee-specific complaints; the details of the index procedure, including perioperative and postoperative treatments; a complete past medical history, including past surgical history, medications, and allergies; and a social history. The details gathered during the history will help facilitate defining the mechanism of failure or the reason for pain and dissatisfaction. There are situations in which the TKA may be symptomatic but the cause of the complaints is not knee related. Therefore, in evaluating the painful TKA, the differential diagnosis should include both intraarticular and extraarticular or remote causes ( Boxes 2.1 and 2.2 ).
The Chief Complaint
The first step in evaluating the patient is to understand the chief complaint. Most often, this is residual pain after the index TKA. Pain may be associated with stiffness, swelling, or instability. The onset and duration of the presenting symptoms should be recorded. It is important to determine whether the pain is the same or different from the pain that was present before the index TKA and whether there was a pain-free interval. It is also important to determine whether a traumatic event occurred after the index TKA.
The Knee History
Once the chief complaint has been determined, attention is directed toward gathering information to facilitate making a diagnosis. The patient’s preoperative diagnosis, functional activity, and level of pain before the index TKA should be obtained. The onset of the pain is important because it can be revealing. Pain that is similar in intensity and location to the pre-TKA pain is most likely related to an extraarticular or remote source, such as the hip or the lumbosacral spine. Pain that manifests postoperatively and is different from the preoperative pain requires further clarification. The nature, onset, duration, location, radiation, and association with rest or activity must be explored. It is critical to establish whether there was a pain-free interval, and if so, whether the current symptoms began months or years after the index TKA. Pain that occurs early in the postoperative period may be related to an acute infection, instability, malalignment, or soft tissue impingement. Pain that is late in onset may indicate component loosening, osteolysis, fracture, or late hematogenous infection. The characteristics of the pain are also revealing (see Algorithm). A sharp, catching pain related to activity is usually associated with a mechanical problem, such as loosening, instability, or soft tissue impingement. Pain at rest may be the sign of an infectious condition or a neurologic problem. Hypersensitivity diffusely around the knee may be related to complex regional pain syndrome (CRPS), whereas generalized pain may be related to fibromyalgia.
Instability or a sense of “giving way” may be described during gait, stair-climbing, or functional activities. A detailed history regarding the use of assistive devices such as a knee brace, cane, or crutches; ability to climb stairs; walking distance; and ability to rise from a chair without the use of hands or other assistance provides some insight into the stability of the knee and the functional ability of the patient. A sense of weakness or buckling may be related to ligament instability, component loosening, or a generalized muscle weakness secondary to insufficient rehabilitation. Patients may describe a locking sensation either in flexion or in extension; in these cases, it is important to differentiate among global instability, flexion instability, and patella instability. In the case of flexion instability, the patient usually reports start-up knee pain when arising from a seated position or a sense of weakness when descending stairs. In extreme cases, with a posterior-stabilized (PS) knee, the knee locks in flexion when the femoral cam jumps over the tibial spine. Patella instability may be subtle, but if it is associated with a patella dislocation, the patient may report the appearance of a deformity as the patella jumps over the lateral femoral condyle.
A detailed record of the postoperative course and prior treatments should be obtained, as should information related to perioperative complications. Questions regarding persistent drainage, swelling, hematoma, and incisional erythema should be asked because of the close association with deep infection. In cases of stiffness or limited motion, the patient’s postoperative rehabilitation program and progression should be detailed. Patient compliance with the physical therapy program can be verified by reviewing the rehabilitation and physical therapy notes. Any attempts at manipulation under anesthesia or use of dynamic splinting should be recorded.
Associated complaints such as fever, chills, and lethargy may indicate a more systemic condition or contributing factor. Acute onset of pain, warmth, or stiffness should provoke questions regarding possible hematogenous infection after a recent dental, colonoscopic, or urologic procedure. Other infectious sources, such as cellulitis or abscesses, should be noted. An exact antibiotic history, both previously and currently prescribed, should be documented because of its importance in determining treatment.
Past Medical and Surgical History
The patient’s past medical and surgical history should be obtained. Certain medical conditions, such as Parkinson disease, diabetes, and morbid obesity, have been proven to have a negative impact on TKA outcomes, and as the number of medical comorbidities increase, so do the complication rates. Diabetes can negatively affect TKA in many ways, including much higher infection risks (3.6% versus 0.4% in nondiabetic patients) and persistent neuropathic pain. Loss of proprioception and ataxia associated with diabetic neuropathy can lead to early failure, especially with malaligned or poorly balanced components. Other systemic illness, such as rheumatoid arthritis, psoriasis, or gout, can affect the outcome of TKA.
A history of any thromboembolic events, either before the index arthroplasty or associated with it, should be elicited, and specifically any experience of deep venous thrombosis (DVT) or pulmonary embolism (PE). Although the rate of DVT remains debatable depending on detection methodology, rates of symptomatic PE are low (0% to 0.5%) in patients receiving prophylaxis after primary TKA with low-molecular-weight heparin, warfarin, or pneumatic compression devices. Postthrombotic syndrome (PTS) is characterized by edema, venous ectasia, hyperpigmentation, varicose veins, venous ulceration, and pain with calf compression after DVT. PTS has been reported in up to 20% to 70% of patients with DVT and can lead to chronic swelling and pain in the limb. More recently, lower rates of PTS (6%) have been seen after DVT. PTS can lead to symptoms after index TKA and can help further stratify high-risk patients before revision TKA.
Information about past surgical procedures, especially orthopedic procedures such as total hip arthroplasty, spinal surgery, or foot and ankle reconstruction, should be obtained. The outcomes of these procedures may have an influence on the outcome of the presenting TKA.
The presence of psychiatric disorders may influence or be responsible for some of the patient’s perceptions referable to the knee. Psychiatric comorbidities also may influence the patient’s response to treatment and should be carefully considered. Sleep disturbance is not uncommon in fibromyalgia and associated psychiatric disorders that may require ancillary treatment. However, this may represent a response to the primary problem, especially if the problem is pain.
It is important to establish the patient’s use of medications, including nonsteroidal antiinflammatory drugs, narcotics, antidepressants, and anxiolytics. In some cases, use of specific medications may suggest comorbid conditions that the patient initially fails to report. Inquiry should be made about any medications that were used to try to alleviate the symptoms but were stopped because they failed to provide benefit. Any drug allergies should be documented. This information aids in determining the appropriate multimodal pain management and antibiotic administration, in addition to avoiding any iatrogenic adverse events. Inquiries should be made if the patient has been under the care of a pain management specialist.
Finally, secondary gain issues must be considered. Important psychosocial issues include narcotic abuse, litigation, and workers’ compensation claims. These confounding variables must be elicited from the patient, because it has been established that such factors can greatly influence the outcome. It has also been shown that despite high satisfaction rates, a large proportion of workers’ compensation patients do not return to their previous occupations after TKA.