Bilateral total knee arthroplasty: Simultaneous versus staging in the same or in twice hospitalization

Abstract

Background and objective

Arthroplasty is the main treatment in patients with advanced knee osteoarthritis. In bilateral lesions, it is frequently performed in two simultaneous or separate surgical procedures. In this regard, the present study aimed to compare the results of knee arthroplasty in two joints simultaneously at two different times.

Method

In general, all 40–70 years old patients in need of complete bilateral total knee arthroplasty (BTKA) were enrolled in this descriptive cross-sectional study during 2009–2016. They were included in three groups of BTKA as simultaneously (n = 272), staging in the same hospitalization (146), and staging in different hospitalizations (245). To assess the quantitative and qualitative function of the knees, patients’ knees were evaluated before the surgery, and one month, three months, and two years after the surgery using the Knee Society Score (KSS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Finally, hospitalization time, anesthesia duration, and medical costs were compared between the three groups.

Results

Based on the results, knee function improved based on WOMAC and KSS scales in all groups after arthroplasty although no significant differences were observed between the three groups. Patients’ satisfaction in simultaneous BTKA was significantly higher compared to the other two groups (P = 0.013). Eventually, complications demonstrated no significant differences between the three groups except for pulmonary and cerebral embolism which were more prevalent in old patients with a high body mass index in the simultaneous BTKA group (P = 0.035 and P = 0.043, respectively).

Conclusion

Overall, simultaneous BTKA is a useful approach for reducing costs while increasing patients’ function and satisfaction although it has certain complications such as embolism in older overweight patients.

1. Introduction

Osteoarthritis (OA) is the most common disease of synovial joints and its rate increases with age. In addition, OA is more prevalent in men and women after 45 and 55 years, respectively,¹ and now, knee OA affects 40% of the population over the age of 70 years.²

Total knee arthroplasty (TKA) is one of the most frequent orthopedic surgeries worldwide and is used to treat degenerative joint diseases (DJDs) in a variety of populations.³ Approximately one-third of patients requiring knee arthroplasty demonstrate the bilateral symptoms of joint disease and thus need bilateral arthroplasty. Totally, surgeons and patients can select two methods of arthroplasty as simultaneously or staging at hospitalization in patients with advanced OA of both knees. Simultaneous bilateral total knee arthroplasty (BTKA) has some advantages including one time of surgery and anesthesia, symmetrical rehabilitation on both knees, and lower hospital costs.⁴ Given that most patients with a need for TKA suffer from severe genu varum^5,6 in the third world countries including Iran, simultaneous BTKA provides symmetrically correction, improves knee function, and resolves disparity by performing rehabilitation and recovery. However, evidence suggests that simultaneous BTKA has severe complications such as cardiovascular problems, embolism, and higher mortality.

The lack of evidence on these topics is considered as the main problem that surgeons encounter when selecting simultaneous or staged BTKA.⁴ Some studies found that the simultaneous approach leads to increased gains in quality-adjusted life years, reduced costs, and decreasing the risk of deep infection and revision rate in most patients as compared to the staged approach. However, other studies reported that the outcomes of simultaneous BTKA were worse compared to staged or unilateral TKAs.7, 8, 9

Considering the fact that the majority of patients in Iran have severe genu varum, when we operate staging in the same or twice hospitalization the operated leg is flattened and 1–2 cm is raised. The result is asymmetric and it will cause problems for the patient. while is not this problem when both knees are simultaneously operated on, but there might be other problems. Due to these issues, the purpose of this study was to investigate and compare the outcomes of BTKA in three approaches of simultaneous, staging in the same hospitalization, and staging in different hospitalizations.

2. Materials and methods

2.1. Patients

This descriptive cross-sectional study evaluated all patients with advanced OA who were treated at an academic orthopedic center during 2009–2016 following the approval of vice chancellor of research and ethic committee of the University of Medical Sciences. More precisely, all patients with advanced OA or DJDs in both knees with grades 3 and 4 of Kellgren-Lawrence criteria were included in this study. These patients had some indications of bilateral total knee arthroplasty (BTKA). BTKA was performed as staged in the same hospitalization with a 3-day interval during 2009–2011, in different hospitalizations within a 3-12-month interval during 2012–2014, and as simultaneous during 2015–2016.

However, patients were excluded from the study if they were <40 and >75 years, had a surgical history of lower limbs, any visual impairment, or balance disturbances, and used disturbance-induced drugs. Therefore, 288, 158, and 256 patients were included from simultaneous TBKA, staged in the same hospitalization, and staged in different hospitalizations groups, respectively. However, 272, 146, and 245 the eligible patients who signed the informed consent forms were followed at a two-year follow-up, respectively. The study was also in accordance with the ethical standards of Helsinki.

2.2. Surgical procedure

Preoperative care such as deep vein thrombosis (DVT) prophylaxis and the intravenous injection of the tranexamic acid were used to reduce intraoperative hemorrhage. All patients underwent surgery by an expert orthopedic surgeon (the first author) under generalized anesthesia. The surgical procedure was similar in all groups as medial para-patellar with cementations and the posterior-stabilized type of NexGen prosthesis (Zimmer, Germany). In addition, all patients received surgical care such as tourniquet application and antibiotic consumption after the surgery or pain control.

2.3. Assessments

Demographic characteristics were recorded before the surgery. Furthermore, to assess the quantitative and qualitative function of the knees, the surgeon evaluated them before the surgery using the American Knee Society Score (KSS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC). The patients were recalled and re-evaluated by these two tools one month, three months, and two years after the surgery. Genu varum and patients’ satisfaction based on the visual analog scale (VAS) were also evaluated in all groups.

Early complications at the first 48 h of admission were evaluated, including hematoma, bleeding, DVT, infection, and embolism. Additionally, patients were given anticoagulants after the surgery to prevent embolism, followed by performing adequate blood and fluid management. In addition, they were encouraged to mobilize and perform isometric knee exercises on the next day of surgery (All patients were encouraged to sit, stand, walk, and climb few stairs on the day of surgery and subsequent postoperative days). Next, patients were discharged and followed up weekly during the first month, then monthly for up to three months, and finally, every six months up to two years. Complications occurring in the first two years and other complications such as mortality and revision were recorded, and then hospitalization time, anesthesia duration, and medical costs were evaluated in all groups. Further, physiotherapy was performed for all patients after discharge in order to prevent DVT, control lower limb edema, obtain a complete joint range of movement, and strengthen the muscles around the joint in twenty sessions daily during the first week after the surgery and then three times per week during two months. All patients performed these passive and active sports activities under the supervision of an experienced physiotherapist to improve knee movements in flexion and extension and strengthen the surrounding muscles. All movements with more focus on extensor muscles were performed using the daily adjustable progressive resistance exercise progressing from isometric to isotonic movements and walking training with a cane and walker.

2.4. Statistical analysis

Data were analyzed using SPSS software, version 21. After evaluating the normality of WOMAC and KSS scores, the Bonferroni test was used to determine the changes of these two scores at different times. Then, the repeated measure ANOVA was utilized to compare the change trend. Finally, the Chi-square test was applied to compare age, gender, and body mass index (BMI), as well as surgical complications, medical cost, hospitalization time, anesthesia duration, and VAS. The result was statistically significant at P < 0.05.

3. Results

In general, 663 patients with advanced knee OA referring to the academic orthopedic center during 2009–2016 were evaluated in three groups. According to Table 1, patients within the age group of 50–60 years and a BMI of 30–35 kg/m² had the highest number in all three groups. Moreover, women were more likely to have OA in all three groups compared to men. However, age, BMI, and gender distribution showed no statistically significant difference between the groups.

Table 1.

Demographic features of all patients.

Variable		Groups
		Simultaneous		Same Hospitalization		Different Hospitalizations
		n	%	n	%	n	%	P
Age	40-50 (year)	83	30.51%	42	28.76%	78	31.83%	0.929
	50-60 (year)	113	41.54%	67	45.89%	96	39.18%
	60-75 (year)	76	27.94%	37	25.34%	71	28.97%
	Total	272	100.0%	146	100.0%	245	100.0%
Gender	Male	78	28.67%	54	36.98%	83	33.87%	0.759
	Female	194	71.33%	92	63.02%	162	66.13%
	Total	272	100.0%	146	100.0%	245	100.0%
BMI	20–25	27	9.93%	18	12.32%	25	10.2%	0.999
	25–30	78	28.68%	41	28.08%	69	28.16%
	30–35	137	50.36%	68	46.57%	118	48.16%
	>35	30	11.02%	19	13.01%	33	13.47%
	Total	272	100.0%	146	100.0%	245	100.0%

Note. BMI: Body mass index.

The WOMAC score of all groups improved significantly from one month to two years (P = 0.001). However, between groups comparison of the mean WOMAC Score was not statistically significant except for the first month after the surgery (Table 2). This statistically significant change had no clinical importance due to the rage of WOMAC Score. On the other hand, changes in the WOMAC score in all groups were not statistically significant before the surgery and one month, three months, and two years after the surgery. Additionally, no significant difference was observed between the groups in terms of the type of surgical procedure (P = 0.768). Furthermore, the interaction of time and surgical methods demonstrated no significant difference in all groups (P = 0.054).

Table 2.

Comparison of mean WOMAC score in Three Groups.

WOMAC	Groups						P-value
	Simultaneous		Same Hospitalization		Different Hospitalization
	Mean	SD	Mean	SD	Mean	SD
Before surgery	57.66	3.68	58.18	4.54	59.63	8.66	0.339
1 month after surgery	80.79	2.77	82.29	3.56	79.87	1.89	0.001
3 months after surgery	88.55	2.47	89.08	3.12	88.74	2.92	0.900
2 years after surgery	93.42	1.80	92.76	1.99	93.34	1.65	0.231
Diff (before to 1 month)	23.13	4.89	24.11	5.76	20.24	7.84	0.023
Diff (before to 3 months)	30.89	4.21	30.89	6.27	29.11	9.15	0.508
Diff (before to 2 years)	35.76	4.11	34.58	4.84	33.71	8.48	0.343
P	0.001		0.001		0.001
P (type of surgery)	0.768
P (time and surgical technique)	0.054

Note. WOMAC: Western Ontario and McMaster Universities Arthritis Index; SD: Standard deviation.

The mean and standard deviation of KSS score in all groups during the preoperative period, one month, three months, and two years after the surgery represented no significant difference. In addition, the comparison of changes in KSS score was not significant in pre-surgical procedures until one month, three months, and two years after the surgery. Conversely, within-group comparisons indicated that KSS score increased significantly in all groups by increasing time from one month to two years after the surgery (P = 0.001). However, the comparison of KSS score between the three groups based on the repeated test revealed no significant difference (P = 0.07). Further, the interactive effect of time and surgical procedures based on repeated and Green House tests was not significant (P = 0.81), the details of which are provided in Table 3.

Table 3.

Comparison of mean KSS Score in Three Groups.

KSS	Groups						P-value
	Simultaneous		Same Hospitalization		Different Hospitalization
	Mean	SD	Mean	SD	Mean	SD
Before surgery	64.29	3.15	63.92	5.52	64.24	3.37	0.91
1 month after surgery	79.79	2.91	78.71	3.05	80.24	2.86	0.07
3 months later surgery	86.95	3.04	85.76	2.35	86.29	2.15	0.13
2 years after surgery	92.32	1.89	92.47	2.29	92.92	2.29	0.45
Diff (before to 1 month)	15.50	5.00	14.79	6.74	16.00	4.54	0.63
Diff (before to 3 months)	22.66	4.81	21.00	3.62	22.05	4.26	0.23
Diff (before to 2 years)	28.03	3.66	27.71	3.30	28.68	3.74	0.48
P	0.001		0.001		0.001
P (type of surgery)	0.07
P (time and surgical technique)	0.81

Note. KSS: American Knee Society Score; SD: Standard deviation.

Among our patients, 58 (21.32%), 24 (16.43%), and 45 (18.36%) cases in three groups of simultaneous TBKA, staged in the same hospitalization, and staged in different hospitalizations suffered from severe genu varum (deformity of more than 10°),¹⁰ which was not statistically significantly different between the three groups. Patients’ satisfaction based on the VAS increased from 2.73 (±0.69) to 9.23 (±0.78), 3.03 (±1.02) to 7.89 (±0.94), 3.27 (±1.24) to 7.39 (±1.08) in simultaneous TBKA, staged in the same hospitalization, and staged in different hospitalizations groups, respectively. Between-groups comparison showed that patients with simultaneous TBKA had significantly more satisfaction compared to the other two groups (P = 0.013).

The percentage of complications including blood transfusion, infection, hematoma, DVT, mortality, and revision in all groups was nearly the same and represented no significant difference (Table 4). However, pulmonary and cerebral embolisms were more common in patients with simultaneous TBKA as compared to the other two groups. Furthermore, 75% of these patients were over 70 years old and had a high BMI. In addition, the hospitalization time in the patients of the staged in different hospitalizations group was more than that of the other two groups while patients with simultaneous TBKA had the least hospitalization time (P = 0.001). As regards the duration of anesthesia, patients were anesthetized between 100 and 110 min in the simultaneous TBKA while those in the staged in the same and different hospitalization groups were anesthetized twice each for 45–50 min (P = 0.001). The medical cost was the lowest in the simultaneous TBKA group whereas patients with staged in different hospitalizations had the highest cost (P = 0.001), the related data are presented in Table 5.

Table 4.

Complications in groups.

Variable	Groups						P-value
	Simultaneous		Same Hospitalization		Different Hospitalization
	n	%	n	%	n	%
Number of patients	272	100%	146	100%	245	100%	-
Transfusion	11	4.04%	8	5.47%	5	2.04%	0.241
Infection	1	0.36%	2	1.36%	2	0.81%	0.999
Hematoma	1	0.36%	2	1.36%	3	1.22%	0.999
DVT	2	0.73%	2	1.36%	3	1.22%	0.859
Mortality	5	1.83%	4	2.75%	4	1.63%	0.917
Revision	4	1.47%	3	2.06%	5	2.04%	0.756
Pulmonary embolism	15	5.51%	1	0.68%	1	0.4%	0.035
Cerebral emboli	13	4.77%	1	0.68%	1	0.4%	0.043

Note. DVT: Deep vein thrombosis.

Table 5.

Duration of admission and anesthesia in patients.

	Variable	n	Mean ± SEM	Min	Max	P-value
Duration of admission (Day)	Simultaneous	272	3.18 ± 0.56	2.00	4.00	0.001
	Same hospitalization	146	6.00 ± 0.66	5.00	7.00
	Different hospitalization	245	6.75 ± 0.84	5.00	9.00
Duration of anesthesia (minute)	Simultaneous	272	108.85 ± 3.12	100	110	0.001
	Same hospitalization	146	46.36 ± 2.04	45	50
	Different hospitalization	245	48.03 ± 1.47	45	50
Cost (Iranian Toman)	Simultaneous	272	3,426,000 ± 1.78	2,971,000	3,728,000	0.001
	Same hospitalization	146	4,128,000 ± 1.31	3,891,000	4,687,000
	Different hospitalization	245	6,671,000 ± 1.79	6,258,000	6,841,000

Note. SEM: Standard error of the mean; Min: Minimum; Max: Maximum.

4. Discussion

The prevalence of advanced degenerative diseases, especially osteoarthritis (OA) is increasing. Unfortunately, one-third of these patients are referred to medical centers with symptoms of bilateral knee lesions and require bilateral knee surgery. Arthroplasty is accepted as an appropriate intervention for relieving pain and symptoms in these patients.¹ Despite studies about the knee arthroplasty, it is unclear which one of simultaneous or staged in hospitalization has superiority over the other. According to the obtained results, knee function improved based on the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the American Knee Society Score (KSS) without any significant difference between the three groups. However, the three groups differed based on the visual analog scale, embolism, hospitalization time, anesthesia duration, and medical costs. In a retrospective study, Agarwala et al. reported 380 cases (760 knees) of sequential simultaneous bilateral TKA (SSBTKA) and 754 cases of unilateral TKA (UTKA) with the mean follow-up duration of 40.59 months. Although the length of hospital stays was significantly longer in the SSBTKA group compared to the UTKA group, the Oxford knee and WOMAC scores in both groups demonstrated a similar increase over time. On the other hand, blood transfusions, cardiac attacks, urinary retention, and deep infection were significantly more common in the SSBTKA group. None of the patients in the UTKA group had to undergo a revision surgery while 2 (0.6%) patients in the SSBTKA group had TKA revision. Both groups were comparable regarding functional outcomes and mortality rates. However, they suggested to perform SSBTKA for suitably chosen patients.¹¹ In another retrospective study, Vaishya et al. analyzed 46 patients with SBTKA aged >70 years (in the range of 70–93 years) based on the fact that older patients occasionally refuse to undergo SBTKA at the same time due to old age, uncertain life expectancy, co-morbidities, and fear of surgical complications. According to their results, 74% had one significant medical condition (e.g., hypertension, diabetes mellitus, coronary artery disease, and chronic obstructive pulmonary disease) or more. However, there was a significant improvement in KSS at six months. They reported that SBTKA can be a safe, successful, and considerable treatment option in carefully selected elderly patients.¹² Similarly, Ritter et al. compared simultaneous BTKA, two-stage BTKA, and unilateral TKA. They concluded that although the incidence of thrombophlebitis was significantly higher in simultaneous BTKA compared to the other two groups, with enough indications for BTKA, simultaneous BTKA was more beneficial for patients compared to the other two methods.¹³ In another study, Huang et al. demonstrated that patients with unilateral and bilateral knee surgeries were not significantly different based on the improvement of knee function using the WOMAC and SF-36 tools.¹⁴ Furthermore, Cross et al. compared simultaneous and two-steps BTKA methods and found that bilateral knee surgeries had no higher risk in comparison with unilateral knee surgery. In addition, both methods had <1% of cardiovascular and deep vein thrombosis (DVT) complications. Their results further showed that the medical cost was lower in simultaneous BTKA compared to the other methods.¹⁵

Based on the results of the present study, patients’ satisfaction after the surgery in simultaneous TKBA was higher compared to the other two groups, implying that simultaneous TKBA helps improve degenerative joint diseases and severe genu varum. Although patients who undergo BTKA in a variety of ways may have different discomfort or dissatisfaction, these factors do not affect the type of surgery because most patients’ conditions improve after the rehab. Therefore, in addition to assessing the improvement of knee function after the surgery in various methods of arthroplasty, other factors such as patient’s safety of life and reduction of mortality, the absence of various complications (e.g., hematoma, infection, transfusion, and the like), and financial issues should be considered for the approval of the type of the surgery.

As previously mentioned, the present study evaluated certain complications such as blood transfusion, infection, hematoma, DVT, mortality, revision, and pulmonary and cerebral embolisms in all groups. The mentioned complications were rare in all groups and did not significantly differ except for pulmonary and cerebral embolisms. The findings further revealed that pulmonary and cerebral embolisms were more prevalent in patients with a high BMI and age>70 years in the simultaneous BTKA group. Our results are in line with those of the study by Wu el at., indicating that women in the age range of 64–76 years and with an average BMI of 32.6 kg/m² had more embolism after TKA. Moreover, they expressed that patients undergoing simultaneous BTKA had a higher risk of pulmonary embolism.¹⁶ Furthermore, Stavros et al. reported that among patients undergoing TKA, women, obese patients, and those with renal and cerebrovascular diseases are more susceptible to embolism compared to others.¹⁷ Therefore, it seems that elderly and overweight patients are unsuitable candidates for BTKA. On the other hand, Sarzaeem et al. concluded that patients undergoing two-step BTKA had no higher DVT in comparison to those with simultaneous BTKA.⁹ However, they indicated that simultaneous BTKA could be a more appropriate choice for patients due to a significant reduction in hospitalization time.⁹ Regarding the mortality and complications of bilateral surgical procedures, one study suggested that age-related factors may affect postoperative complications in the first year after the surgery.¹⁸ In the current study, the mortality rate was lower than 5% in all groups which was partly due to their age. According to, when the distance between the surgeries of the two knees is prolonged, the complication rate may represent an increase. Thus, complications such as hematoma and spinal cord injury in patients with BTKA were more frequent than those of the other two groups.

In our study, the level of blood transfusion demonstrated no difference in the three groups. In addition, the intravenous and intra-articular injections of tranexamic acid were used in all groups after the surgery and none of the groups showed a difference in terms of the need for transfusion, which is probably due to a reduction in bleeding after the surgery. However, Fu et al. found that simultaneous BTKA due to double-sided bone cutting and high levels of trauma may increase the amount of bleeding and reported that transfusion levels in these patients were higher compared to the other groups.¹⁹

Further, the rate of knee infection immediately after the surgery was extremely low in all groups. Only one patient in the simultaneous TBKA experienced acute infection and thus underwent immediate treatment. Two patients in each of the two other groups were also infected possibly due to the lack of patient care and the distance between the surgeries.

Based on our results, simultaneous BTKA and staged in different hospitalization groups had the lowest and highest hospitalization time, respectively. Furthermore, the duration of anesthesia was one of the factors that differed between the three groups. In simultaneous BTKA, the duration of anesthesia was greater in comparison to the other two groups. Moreover, patients spent less money in simultaneous BTKA compared to the other two groups due to a decline in hospitalization time. Similarly, Aaron et al. showed that BTKA was less costly in terms of different payment items including diagnosis, rehabilitation, surgical, laboratory, drug, and anesthesia costs.²⁰ In our study, the simultaneous TBKA was more cost-effective than the other two methods. However, the present study did not analyze comorbidities and prosthesis component positioning and the restoration of limb alignment, which is considered a limitation. Thus, it is recommended that future studies take into account the above-mentioned parameters.

5. Conclusion

The findings of the present study revealed that simultaneous bilateral total knee arthroplasty is a suitable method for reducing the cost of treatment and the length of hospitalization. In addition, it helps increase the level of satisfaction in patients with severe osteoarthritis and severe genu varum. However, unusually the rate of cerebral embolism in this method is higher in patients with overweight and high age and the reason for this seems to require further study.

Declaration of competing interests

None.