Patient Selection

(1)

Department of Orthopedic Surgery ASAN Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of South Korea

Abstract

Here, I have used the term “patient selection” instead of the medical term “indication” because total knee arthroplasty (TKA) is an elective and is not an emergency or lifesaving procedure. Hence the patient’s physical condition and their socioeconomic status should be considered while planning the operation.

The success of the TKA is closely related to the patient’s satisfaction, which is reflected mainly by the relief of pain and improvement of function as well as psychological relief which is manifested by improvement in the quality of life. Even though the operation is successful, the knee joint function cannot return to normal. Oriental patients experience many instances of inconveniences as they are required to kneel down frequently due to their traditional lifestyle. In some patients, pain may persist to a greater or lesser extent even after arthroplasty. Also, TKA cannot be successful in all cases. If the operation fails, the condition of the knee joint would be worse than that before the operation. Even if the operation is successful, since the artificial joint does not assimilate into the human body, a revision surgery is needed after a certain period of time.

Therefore, it is desirable to carefully consider the advantages and drawbacks of TKA before taking the decision to perform the operation.

1.1 Social Conditions

Social conditions generally include the patients’ family, surroundings, and patients’ activities.

In most of the oriental societies, the patients live together with their children, although this tradition is changing gradually. Even when the patients live apart from their children, most of the families start living together again when their parents are seriously ill.

Many problems may develop within the family, in case the patient is unable to walk. In such a situation, it is desirable to perform arthroplasty in order to regain mobility as early as possible. In fact, family satisfaction is greater than patient satisfaction if the operation is successful. This indicates that the life of the family members of the patient becomes better as a result of freedom from caregiving, while the patients themselves continue to have difficulty while performing the activities of daily living such as kneeling down and sitting on the floor, despite of being able to walk without pain. Total knee arthroplasty can be delayed if the family members are affectionate towards the patients.

Therefore, the family’s attitude towards the patient, patient’s activity level, and patient’s motivation to modify their lifestyle are important factors to be considered while deciding to perform the operation.

1.2 Economic Conditions

Economic conditions also have a considerable impact on patient satisfaction. In case of elderly patients, high hospitalization costs can lead to an increase in the patient’s anxiety level, thereby resulting in a poor prognosis. If the patient’s socioeconomic condition is not good, he/she may need to return to work after the operation. Therefore, total knee arthroplasty is indicated in the patients who have the ability to pay the hospitalization charges without much difficulty and who can make a living without doing any laborious work after the surgery.

1.3 Psychological Conditions

Although psychological conditions are easily overlooked, they are closely related to the patient’s perception of pain. The patient’s psychological condition also affects the postoperative rehabilitation. If patient motivation is poor and the patient is not willing to follow the surgeon’s instructions, the results of TKA may not be satisfactory. The patients who lack motivation, have been forced to undergo an operation by the family, are stubborn or dependent, and are accustomed to complain about minor discomforts have a lower level of satisfaction after the surgery. The patients who have a rigid mindset towards the outcome of TKA or are oversensitive to pain also show poor results.

The patient’s expectations should not be too high. If the patients expect that their knee joint function will return to normal and they can get involved in vigorous sports activities and laborious work, the decision to perform a TKA should be reconsidered. Scott et al. and Noble et al. reported that postoperative patient satisfaction is primarily dependent not on the knee joint function but on the patients’ expectations. Hepinstall et al. suggested that high, unrealistic expectations of TKA are common and should be moderated to maintain patient satisfaction. Culliton et al. reported that preoperative expectations did not correlate with postoperative satisfaction. However, postoperative satisfaction was predicted by how well preoperative expectations were met after surgery. Therefore, patient education program for managing expectations should be established on the other hand Gandhi et al. reported that although young, male, and low-BMI patients have higher expectations from TKA, they get better pain relief.

If the patient seems to suffer from a psychological disorder or depression, it is recommended to consult a psychiatrist prior to the operation so as to assess whether the patient’s psychological condition can be optimized with medications. Ellis et al. reported that psychopathology such as presence of somatization, depression, and/or a panic or anxiety disorder showed significantly higher levels of perception disability even though these patients still benefit with same degree of improvement in function. They recommended routine assessment for psychological distress prior to TKA. However, in contrast to the general assumption that the prognosis would be worse in patients with a psychological disorder, Riddle et al. and Lingard and Riddle reported that postoperative pain is not related to the presence of psychological disorders. Brander et al. also reported that the presence of psychological disorders affects the prognosis, but only until postoperative 1 year, and it has no effect on the prognosis thereafter.

Dementia is not a contraindication for TKA, but a patient suffering from dementia is not a good candidate for TKA as his/her behavior can be quite erratic.

1.4 Indication

An indication refers to the physical condition. The indication should be decided according to the age of the patient, patient’s physical condition, and condition of the knee joint.

1.4.1 Age

Age is a very important factor in deciding the indication, since we must take into account both the patients’ activity level and implant survival. If the patients are young, there is a higher possibility of the need of revision surgery because young patients are more active and they live longer than the duration of implant survival. Revision TKA is technically more difficult than primary TKA, and the prognosis is not as good as that of primary TKA. So, it is desirable that the patients benefit from the TKA throughout their life without requiring revision TKA. However, developments in implants and surgical techniques for primary and revision TKA and prolonged life span have resulted in widening of the indications based on the patient age.

TKA is not indicated in teenagers because they are skeletally immature.

In the 3rd–5th decade of life, TKA can be indicated for ankylosed knees, far advanced secondary OA, or rheumatoid arthritis. It is not appropriate to expect the young patients to tolerate the extreme pain just because they are young. TKA can be of great help to the patients who have been suffering from uncontrolled pain and who are bedridden due to polyarthritis.

In the 6th decade of life, if the pain and functional disturbance is not very severe, the conservative treatment should be tried or joint-conserving operations such as chondroplasty, high tibial osteotomy, and unicondylar arthroplasty can be performed. Of course, TKA is indicated for advanced osteoarthritis and rheumatoid arthritis in this age group. Crowder et al. reported that they achieved good clinical results in the patients of rheumatoid arthritis who were younger than 55 years of age. A few surgeons recommend arthrodesis of the knee in the younger age group, but I have an opposite opinion taking two aspects into consideration. The first aspect is that the handicap associated with an ankylosed knee is much more than that with the ankylotic hip with respect to walking the stairs, voiding, getting into a car, and performing the activities of daily living. And hence the patient is likely to be isolated from the society and can lose his/her financial independence. The second aspect is that it is much easier to perform arthrodesis for failed TKA than for failed THA. If a TKA fails, arthrodesis of the knee joint can be performed more easily afterwards.

However, performing TKA in the young patients with severe arthritis is quite different from converting the ankylosed joint to a mobile joint. In other words, if a young patient has severe pain and functional disturbance and he does not engage in laborious work, TKA may be considered instead of knee fusion, whereas if the joint is ankylosed in a young laborer, it is better not to convert the ankylosed joint to a mobile joint.

The most appropriate age for TKA is around 65 years. At this age, the patient does not engage in laborious work, and he/she may not need to undergo a revision operation since the average life span is around 80 years. Also, the patient’s physical condition is relatively good at this age, and the risk of operation is not very high. When 5 years are added or subtracted from this age of 65 years, the patients in the age group of 60–70 years are a good indication for TKA according to the knee joint condition.

Between 70 and 80 years of age, TKA can be considered in patients having moderate pain and moderately advanced osteoarthritis. Osteoarthritis will progress in the near future, and passing the time away by attempting conservative treatments and waiting for an absolute indication will make the situation more difficult for performing an operation as the patient gets older.

It is not recommended to perform TKA in young patients, but also many problems may occur when TKA is performed in patients who are too old. When the patient is too old, the risk of operation increases, and the prognosis may not be as good due to comorbidity and muscle weakness. If some unfavorable events occur, the result may be worse than that without the operation. When the patient’s age is more than 80 years, the decision of performing an operation should be made very carefully, and it may be better not to perform a TKA unless the patient is really healthy, although there are also some reports suggesting that there is no difference in the outcomes and morbidity after TKA in the patients more than 80 years of age. Alfonso et al. reported through the survey of 25 TKAs performed in patients more than 90 years of age that the pain was decreased and life span was extended as compared to that in the population belonging to the same age group who did not undergo a TKA. However, they experienced operation-related complications in 80 % of the cases and medical comorbidities in 56 % of cases.

Briefly, TKA is contraindicated in skeletally immature patients, but operation can be performed in patients less than 60 years of age if the symptoms are severe, and the best age for TKA is 60–70 years. TKA can be considered in moderately advanced osteoarthritis in 70–80-year-old patients. Patients more than 90 years of age should undergo TKA only in extremely exceptional cases. However, surgeons should take into account the chronological age as well as the physiological age. This should be done since some patients look healthier than their chronological age and vice versa.

1.4.2 Physical Conditions

1.4.2.1 General Conditions

Patient’s general condition is likely to worsen postoperatively due to anorexia, insomnia, and voiding difficulties. Poor general condition of the patient has an adverse effect on wound healing and muscle strength which leads to a poor prognosis, and fatal results may occur due to comorbidity.

Most of the patients have hypertension, diabetes mellitus (DM), cardiopulmonary, renal, and other endocrine disorders. Hypertension, DM and other endocrine disorders are not a contraindication for TKA as they can be controlled perioperatively. The presence of cardiovascular and renal disorders is closely related with patient’s capacity to endure the operation and their postoperative activity level. Meding et al. screened 1,438 patients preoperatively and reported that 8.3 % of the patients had cardiovascular problems, 7.2 % had chronic obstructive pulmonary disease, 56 % had hypertension, 37 % had gastrointestinal problems, and 12 % had DM. Among them, 2.5 % of patients were not suitable for the operation. Huddleston et al. reported that cardiovascular problems occurred in 3.9 % of patients among 2,033 TKA patients. Memtsoudis et al. reported fatal results in patients who underwent revision, who were old, and in patients with comorbidities and dementia. The most common causes of death were pulmonary embolism and cerebrovascular accident. Lingard and Riddle and Long et al. demonstrated, through the survey of the patients, that the better the patient’s preoperative physical condition, the better the prognosis and the higher the patient satisfaction.

1.4.2.2 Obesity

Patients with obesity have a higher incidence of osteoarthritis. The patients whose body mass index (BMI) is over 25 are categorized as obese. Obesity by itself cannot be a contraindication for TKA, but experience of the surgeon is needed to achieve a better result of TKA in morbidly obese patients. I personally believe that the more the patient is obese, the more difficult is the surgical performance. According to the annual report of 2005, about 24 % of the whole population in the United States can be categorized as obese. Fehring et al. reported that about 52 % of their TKA patients were obese. The surgical performance and prognosis of TKA may be adversely affected when BMI is above 30, or body weight is more than 200 lb or 100 kg.

It is generally agreed that obesity increases the complications such as wound problems, patellofemoral maltracking, and wear and loosening resulting in decreased implant survival rate. Foran et al. reported worse clinical results and also reported that the incidence of revision was increased due to wear and loosening in obese patients. Kerkhoffs et al. reviewed 15,276 patients and reported the result of meta-analysis that deep infection occurred more often and revision rate was increased in patients whose BMI is more than 30. Dewan et al. stated that the morbidly obese patients whose BMI was over 40 showed muscle weakness and extensor mechanism dysfunction postoperatively. Gadinsky et al. found that patients with higher BMI had lower preoperative and postoperative ROM. However, Amin et al. and Bastis et al. reported that obesity had no adverse effect on the knee joint function and did not lead to an increase in the complications at the midterm follow-up of TKA.

1.4.2.3 Neuromuscular Conditions

In the presence of paralysis of the opposite lower limb, the indication for TKA is decided on the basis of how severe is the pain in the knee joint that needs to be operated, how much is the strength of muscle power in both lower limbs, and whether the patient can at least walk with crutches preoperatively. Generally, arthroplasty may be indicated when the muscular strength of the limb to be operated upon is greater than grade IV.

Parkinson’s disease is a relative contraindication since there is motor incoordination and muscle tremor along with affective disorder, and it is a progressive disease.

The most difficult patient to decide operation is the one who has a minor or latent cerebrovascular lesion which cannot be detected by the symptoms and on physical examination. So, in case of any doubt, a preoperative work-up should be performed for detecting cerebrovascular lesion in the patients who have a history of cardiovascular problems or if the patient is very old.

1.4.2.4 Spinal Conditions

Patients with osteoarthritis often have accompanying spinal stenosis. Even if they do not feel any pain in the back, it might have been masked since they have more pain in the knees and they may experience back pain when the knee pain disappears.

A coexisting spinal stenosis may require an operative intervention as well. Surgeons should decide the priority of the operation that is to be performed first, since the physiological stress is increased if two major operations are performed within a short time span. Motor power and the severity of pain is the determining factor for deciding which operation between the spinal operation and TKA is to be performed first. If there is accompanying motor weakness, it is strongly recommended to perform the spinal operation first. If the pain intensity is nearly the same at both the sites, it is recommended to perform the spinal operation first. This is because the patient satisfaction is decreased when the back problem persists, no matter how successful the TKA is. When TKA is being planned, it is indicated only when the muscle power is at least greater than grade IV.

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