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Abstract

Background:

There are many factors that affect the experience and satisfaction of a patient undergoing knee replacement surgery.

Objective:

This study aims to explore the effects of demographic factors, disease severity and several novel parameters on patients’ expectations in a Singaporean population.

Methods:

Phone interviews were conducted with 69 patients to measure their expectations before total knee arthroplasty (TKA). Information such as demographics, surgical histories, baseline Medical Outcomes Study Short Form 36 (SF-36) score, Knee injury and Osteoarthritis Outcome Score (KOOS), Lower Extremity Activity Scale (LEAS), kneeling ability, quality of reviews from relatives or friends and histories of any traditional therapies utilised were obtained. Radiological severity of osteoarthritis was graded using the Kellgren–Lawrence scale; discordance with severity of knee pain was recorded.

Results:

Patients expected TKA to result in pain relief, improved mobility, increased ability to participate in physical activities, and paid employment. On multivariate regression analysis, LEAS, SF-36 physical, KOOS-pain and KOOS-activity of daily living scores remained significant predictors of expectations.

Conclusion:

The results indicated multiple factors influence patient’s expectations pre-operatively and their satisfaction post-operatively. Better patient outcomes may be achieved by making improvements in understanding and moderating patient expectations.

Level of evidence:

Diagnostic III

Keywords

Total knee arthroplasty Patient Expectations Health Instruments Asian population

Introduction

By 2020, age-related chronic musculoskeletal conditions such as osteoarthritis of the knee are expected to be the fourth leading cause of disability in Singapore.¹ This painful, debilitating condition frequently necessitates total knee arthroplasty (TKA) to improve pain, functionality and quality of life.^2,3 Patient expectations affect perceived and objective outcomes following joint arthroplasty surgery.^4–8 While better outcomes were reported in patients with higher expectations, unfulfilled expectations can result in dissatisfaction,⁹ and patients whose expectations have been fulfilled are more likely to be satisfied after joint arthroplasty.^8,6

In American populations, patient attributes such as age, race, gender and education level, and disease factors, better pre-operative general health and activity level and increased pre-operative disease severity have been shown to significantly impact patient expectations.^4,7,10–12 Demographic factors, socioeconomic background, severity of pain and disability may also influence patients’ expectations and post-operative outcomes.

This study aims to explore the effects of patient and disease factors on expectations before TKA in a consecutive series of patients (n=69) scheduled to undergo the procedure. We hypothesise that factors unique to the Asian population, such as the ability to kneel, quality of previous reviews from relatives and friends, usage of traditional therapies, and radiographic severity and degree of pain discordance would influence expectations in patients.

Methods

One hundred consecutive patients with osteoarthritis scheduled for TKA were approached, of which 69 patients gave consent to participate in the study. Demographic information such as age, sex, highest education attained, and living situation was collected.

We performed a cross-sectional study of 69 patients with osteoarthritis of the knee awaiting TKA between August 2011 and April 2012. Inclusion criteria were patients with osteoarthritis of the knee awaiting TKA, and without diagnosed cognitive disorders potentially interfering with the understanding of questions posed to them. Patients awaiting revision surgery for a previous TKA, awaiting unicompartmental knee arthroplasty, patient refusal, and failure to update change of contact number before surgery were excluded from the study.

Appropriate institutional review board approval was obtained for the study. All patients awaiting TKA were interviewed by a research assistant via phone and were administered questionnaires with verbal explanations and clarifications as necessary. Five call attempts were made at different times of the day to contact patients for the phone interviews.

All patients underwent pre-operative counselling and consent-taking by the consultant orthopaedic surgeon performing the surgery. The alternatives to surgery, potential complications, surgical and post-operative process and rehabilitation goals and timelines were explained to patients with consent forms and relevant patient information brochures. The counselling process was not standardised, but tailored to each individual patient profile.

Reports of the ability to kneel, quality of reviews from close friends or relatives, usage of traditional therapies and pain score with a verbal pain scale (VPS) ranging between 0 and 10 were also obtained.¹³ Patients’ VPS were rated against the radiographic severity of their knee using the Kellgren–Lawrence grading.¹⁴ They were deemed to have X-ray (XR) findings and pain discordance if their XR findings were mild, grade 1 and 2 but had high VPS scores from 5 to 10, and if they had severe XR findings grade 3 and 4, but low VPS scores from 0 to 4.¹⁵

The Knee Expectations Survey was scored according to a previously published system.^16,17 Pre-operative general health status was measured using the Medical Outcomes Study Short Form 36 (SF-36), and summated scores were calculated for both physical and mental components.^18–20 Disease severity was measured using the Knee injury and Osteoarthritis Outcomes Score (KOOS) and standard scores were calculated: Pain, Symptoms, Activities in Daily Living (ADL), Function in Sport and Recreation and knee-related Quality of Life (QOL).²¹ Pre-operative activity was measured using the lower Extremity Activity Scale (LEAS) which had a single score calculated as originally described.²²

Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) v20. The distribution of the expectation scores was skewed towards higher expectations in concordance with previous studies. We thus reported median scores in addition to means, and a nonparametric approach was adopted for hypothesis testing. Relationships between continuous variables and expectation scores were determined using Pearson correlation coefficients (r). The magnitude of the coefficient r designates the strength of the linear correlation between two variables, with an r value greater than 0.6 representing a strong correlation, 0.3 < r < 0.6 representing a moderate correlation, 0.1 < r < 0.3 representing a weak correlation, and any value less than 0.1 representing a negligible relationship.²³ Wilcoxon rank sum tests and Kruskal–Wallis nonparametric tests were used to determine the relationships between the categorical prognostic variables and expectations. Significant prognostic variables from the univariate analyses were then incorporated into a multiple regression model against outcome scores of patient expectations.²⁴

Results

The mean age of the 69 patients enrolled in this study was 64.8 (SD 9.2) years. In total, 17 males and 52 females were enrolled and the three major ethnicities were represented, 59 Chinese, five Malay and five Indian participants. A substantial number of patients (23) did not receive formal education; there were fewer patients in each successive category (primary/secondary/tertiary). Four patients received tertiary education. The majority of the patients lived with another person; 11 stayed with family members or friends and 52 stayed with their spouse.

The mean expectation score of 69 patients was 70.5 (SD15.1). The top three expected outcomes expressed by the patients were pain relief (98.6%), improve ability to squat (98.6%) and ability to go down stairs (97.1%) as outlined in Table 1. Some 54 patients (78.3%) expressed maximal expectations in improving their ability to walk, and 50 patients (72.4%) expressed maximal expectations for pain relief. The three lowest expectations were improvement in sexual activity (37.7%), removal of need for walking aids (47.8%), and improvement in ability to perform daily activities including household chores and straightening of the knee or leg (71.0%).

Table 1.

Expectations, Maximum Expectations and Expected Outcomes of Patients.

Expectation	Maximum expectation (%)	Expected outcome (%)
Pain relief	50 (72.4)	68 (98.6)
Relieve some pain	1 (1.5)
Relieve most pain	20 (29.4)
Relieve all pain	47 (69.1)
Improve ability to walk	54 (78.3)	66 (95.7)
Short distance (indoors, <1 bus stop)	0 (0)
Medium distance (outdoors, <1 km)	14 (21.2)
Long distance (>1 km)	52 (78.8)
Remove need for walking aids	17 (24.6)	33 (47.8)
Straighten knee or leg	29 (42.0)	49 (71.0)
Going up stairs	44 (63.8)	66 (95.7)
Going down stairs	43 (62.3)	67 (97.1)
Improve ability to kneel	18 (26.1)	66 (95.7)
Improve ability to squat	21 (30.4)	68 (98.6)
Improve ability to use public transport	40 (58.0)	60 (87.0)
Paid employment	46 (66.7)	63 (91.3)
Improve ability to participate in leisurely activities	25 (36.2)	64 (92.8)
Improve ability to perform daily activities including household chores	35 (50.7)	49 (71.0)
Improve ability to exercise	16 (23.2)	66 (95.7)
Improve ability to change position	44 (63.8)	64 (92.8)
Improve ability to interact with others	33 (47.8)	50 (72.5)
Improve sexual activity	3 (4.3)	26 (37.7)
Improve psychological well-being	32 (46.4)	50 (72.5)

An overwhelming majority of the patients (95.7%) expected an improved ability to kneel, to exercise and to climb staircases. Other expectations expressed by many patients include an improved ability to change positions and to be able to participate in leisurely activities (92.8%), obtaining paid employment after surgery (91.3%), ability to utilise public transport (82.7%), and 72.5% of patients expected improved ability to interact with others, as well as improved psychological well-being (72.5%).

Among patients who were scheduled for TKA, there were 33 left knees with a mean expectation score of 75.0 and 36 right knees with a mean expectation score of 66.5, p=0.022. Of the patients, 37 were able to kneel and 32 were unable to at the time of study. Six patients had received negative reviews from their friends and relatives regarding the procedure, 42 had mixed reviews and 21 had positive reviews. Eleven patients sought and were undergoing traditional therapies while 58 patients did not. Some 35 patients had XR–pain discordance while 34 patients had XR findings in concordance with their pain levels.

Of all categorical variables, only knee site and living situation were statistically significant for difference in expectations, as depicted in Table 2. Patients living alone had higher expectation scores (84.8) than patients living with others (71.1) or their spouse (68.8) (p=0.022).

Table 2.

Correlation of Categorical Variables and Expectation Score.

	n (%)	Expectation score		Statistical significance
	n (%)	Mean	Standard deviation	Statistical significance
Sex				0.824
M	17 (24.6)	69.9	14.0
F	52 (75.4)	70.7	15.6
Knee site				0.022
Right	36 (52.2)	66.5	14.6
Left	33 (47.8)	75.0	14.7
Race				0.400
Chinese	59 (85.4)	69.8	16.0
Malay	5 (7.3)	71.1	7.5
Indian	5 (7.3)	78.6	7.7
Education				0.129
None	23 (33.3)	65.8	14.0
Primary	22 (31.9)	70.6	19.8
Secondary	20 (29.0)	74.7	9.1
Diploma & higher	4 (5.8)	76.4	13.0
Living situation				0.022
Alone	6 (8.7)	84.8	7.0
With others	11 (15.9)	71.1	15.2
With spouse	52 (75.4)	68.8	15.1
Kneeling				0.709
Yes	37 (53.6)	71.8	15.0
No	32 (46.4)	69.1	15.5
Reviews				0.654
Negative	6 (8.7)	70.7	23.0
Mixed	42 (60.9)	71.4	15.3
Positive	21 (30.4)	68.8	12.8
Traditional therapy				0.634
Yes	11 (15.9)	66.4	21.0
No	58 (84.1)	71.3	13.9
XR–pain discordance				0.976
Yes	35 (50.7)	70.1	15.3
No	34 (49.3)	71.0	15.2

The baseline health instrument scores and their correlation with expectation scores are depicted in Table 3. Age and VPS showed weak, statistically insignificant correlations with expectations.

Table 3.

Correlation of Baseline Health Instrument Scores and Expectation Scores.

	Mean	Standard deviation	Median	Pearson correlation coefficient	p-value
Age	64.8	9.2	65.0	−0.10	0.937
VPS	8.4	2.7	8	0.127	0.298
LEAS	5.9	2.5	6	0.262	0.030
SF-36 Physical	48.4	23.2	49	0.451	0.000
SF-36 Mental	60.7	24.3	66	0.351	0.003
KOOS-Pain	59.4	22.1	62	−0.381	0.001
KOOS-Symptoms	61.9	21.9	61	−0.298	0.013
KOOS-ADL score	60.00	23.0	66	−0.371	0.002
KOOS-Sports and Recreation	13.9	16.2	10	−0.146	0.230
KOOS- Quality of Life	51.4	32.4	56	−0.535	0.000

Univariate analysis indicated a weak correlation between LEAS and patient expectations (r=0.262, p=0.030), implying that patients who were more active had higher expectations. We also found moderate correlation between SF-36 physical components and expectations (r=0.451, p=0.000) and SF-36 mental components and expectations (r=0.351, p=0.003) in our univariate analysis. This implied that healthier patients, as assessed by their mental and physical components, had higher expectations of knee replacement surgery.

Our univariate analysis also found a weak correlation between patient expectations and KOOS-symptoms (r=−0.298, p=0.013) and a moderate correlation between patient expectations and KOOS-pain (r=−0.381, p=0.001), KOOS-ADL (r=−0.371, p=0.002) and KOOS-QOL (r=−0.535, p=0.000). KOOS-Sports and recreation scores showed a weak but statistically insignificant relation to patient expectations. This implied that patients with lower pre-operative disease severity had higher expectations.

Multivariate regression analysis of the 69 patients with complete data showed that LEAS, SF-36 physical and mental scores, KOOS-pain, KOOS-symptoms, KOOS-ADL scores and KOOS-quality of life remained as statistically significant predictive variables for patient expectations. The results of the multivariate regression analysis are shown in Table 4.

Table 4.

Multivariate Analysis of Predictive Variables for Patient Expectations.

	Mean	Standard deviation	Pearson correlation coefficient	p-value
Age	64.8	9.23	−0.100	0.468
VPS	8.4	2.7	0.127	0.149
Kellgren–Lawrence grading	2.9	0.9	0.073	0.275
LEAS	5.9	2.7	−0.262	0.015
SF-36 Physical	48.4	23.2	−0.451	0.000
SF-36 Mental	60.7	24.3	−0.351	0.002
KOOS-Pain	59.4	22.1	−0.381	0.001
KOOS-Symptoms	61.9	21.9	−0.298	0.007
KOOS-ADL score	60.00	23.0	−0.371	0.001
KOOS-Sports and Recreation	13.9	16.2	−0.146	0.115
KOOS-Quality of Life	51.4	32.4	−0.535	0.000

The results of our study demonstrate that Singaporeans undergoing TKA have high expectations with regards to obtaining pain relief and improvement in mobility, ascending and descending stairs, squatting and kneeling. Interestingly, even though the mean age of our patients was 64.8, 91.3% of the study population expected improvement in ability to obtain paid employment, 92.8% expected improvement in ability to participate in leisurely activities and 95.7% of the patients cited improved ability to exercise as an expected outcome from surgery. As the population ages, we may see an increasing number of ‘young’ elderly patients with evolving physical requirements²⁵ that may require differing techniques and implant choices.

Discussion

Our study demonstrated that Singaporeans pre-TKA had high expectations for pain relief and improvement in mobility including climbing staircases, squatting and kneeling. Across all analyses, patients who were more active, healthy both physically and mentally, stayed alone, and/or with lower pre-operative disease severity scored higher for the expectations survey. This implies that patients expect surgery to provide them with a level of independence similar to that of their ability.

Interestingly, although the mean age of patients was 64.8 years – past the official retirement age of 62 (at time of publication) – 9 in 10 patients expected improvement in ability to obtain paid employment. As the population ages, we may witness more ‘young’ elderly patients with evolving physical requirements²⁵ that require differing techniques and implant choices.

Patient demographics did not appear to be a significant factor in patient expectations. The current literature has produced conflicting evidence on the associations between age, gender, race^10,11 and patient expectations.^2,17,26 Lingard and the Kinemax Outcomes Group conducted a multicentre study of 598 patients comparing factors affecting patient expectations in the United States of America, the United Kingdom and Australia, and found significant associations between expectations and age, sex, race or marital status.⁴ Mahomed et al. conducted a multicentre study in The United States and Canada and found no correlation between the same demographic factors and patient expectations.⁵

We recruited from a high-volume referral centre in an affluent urban community. Many patients who were referred to our institution are well insured, have good social support networks and lead active lifestyles, which may have confounded the study. Consequently, our findings may not apply to all patients across all healthcare settings, but we believe it reflects the current demographic of patients undergoing knee replacement surgery. While cultural practices may differ between ethnicities, we believe that the increased cross-cultural interactions and homogeneity of housing and living situations among the elderly in Singapore account for the disagreement with the results of other studies.

We had hypothesised that patients’ education levels, quality of reviews from relatives and friends, ability to kneel pre-operatively, traditional therapies and XR–pain discordance would affect patient expectations. The factors were, however, all statistically insignificant. This probably stems from the fact that most medical information and expectations are obtained from the physician rather than from relatives, friends and traditional therapists.

Patients with mild radiological disease but high VPS were hypothesised to have a lower pain threshold and may have higher expectations from surgery. This was not found to be true, as radiological grading of disease does not always correlate proportionally with symptom severity and is thus a poor surrogate marker of disease severity.²⁷ Its utility in predicting patient expectation is thus limited.

A patient’s pre-operative activity levels, LEAS, general physical and mental health, SF-36 physical and SF-36 mental, and degree of disease severity, KOOS, were found to be significantly correlated with patient expectations. This agrees with previous studies demonstrating that healthier patients with milder existing disease have higher expectation of TKA.^26,2 It would thus be important to modulate the expectations of younger, healthier patients coming for knee surgery so as to obtain better patient satisfaction scores when expectations are met.

Limitations of our study include the small numbers compared with other registry studies (n=69) and high rejection rate (31%). We believe that the small numbers were partially mitigated by the quality of the interviews, as all patients received adequate explanations in whichever language or dialect they were comfortable with. There may also be a bias in patient screening and selection. Patients with other significant medical or socioeconomic problems are likely to have lower expectations, and are more likely to have rejected knee replacement surgery in favour of conservative management options. The orthopaedic surgeon and anaesthetists may also have introduced a screening bias when they rejected patients whom they deemed unfit for surgery despite their history of severe joint disease.

We predict that the expectations of patients with severe joint disease regarding surgery may be more reflective of the general population if the screening was done on all patients who present with severe joint disease requiring surgery rather than only patients selected for surgery. This is a consideration for future studies, to be compared against expectations of conservative treatment options.

Conclusions

In conclusion, patients scheduled for TKA have high expectations of the surgery with regards to pain relief, mobility on flat ground and staircases, and improving ability to squat, kneel and exercise. Healthier, independent and active patients were more likely to have higher expectations of surgery and need to be counselled appropriately regarding aims of surgery and potential outcomes so as to modulate their expectations.

Footnotes

Acknowledgements

The authors would like to thank TYH for contribution of patients for the study and the study subjects for their participation.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Availability of data and materials

The datasets generated and analysed during the current study are available from corresponding author.

Authors’ contributions

BD wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.

Conflict of interest

Co-author SSS is an unpaid faculty consultant with Stryker.

Informed consent

Written patient informed consent was obtained from the patients for their anonymized information to be published in this article.

Ethical approval

Ethical approval to report these cases was obtained from National Healthcare Group Domain Specific Review Board.

ORCID iD

Benjamin Tze Keong

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Expectations of Singaporean patients concerning activities after total knee arthroplasty

Abstract

Background:

Objective:

Methods:

Results:

Conclusion:

Level of evidence:

Keywords

Introduction

Methods

Results

Discussion

Conclusions

Footnotes

Acknowledgements

Funding

Availability of data and materials

Authors’ contributions

Conflict of interest

Informed consent

Ethical approval

ORCID iD

References