Predicting Surgical Factors for Unplanned Overnight Admission in Ambulatory Arthroscopic Surgery of the Knee: A Prospective Cohort in 184 patients

doi:10.21203/rs.3.rs-870705/v1

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Predicting Surgical Factors for Unplanned Overnight Admission in Ambulatory Arthroscopic Surgery of the Knee: A Prospective Cohort in 184 patients

https://doi.org/10.21203/rs.3.rs-870705/v1

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Background: Unplanned overnight admission (UOA) is an important indicator for quality of care with ambulatory knee arthroscopic surgery (AKAS). However, few studies have explored the factors related to the UOA and how to predict UOA after AKAS. This study aimed to evaluate the effectiveness of a standardized perioperative protocol for the AKAS with UOA and identify whether a correlation exists between the perioperative surgical factors and UOA in the patients undergoing AKAS.

Methods: A prospective cohort study was conducted, between October 2017 and March 2021, in 184 patients. All patients operated on standard AKAS protocol. The UOA was defined as overnight hospitalization of a patient undergoing AKAS. Demographic and perioperative data were recorded, and the procedure was categorized based on the surgical invasiveness based on less invasive (n = 65) and more complex surgery (n = 119). The clinical risk factors for UOA were identified and analyzed with multivariate logistic regression analysis.

Results: The incidence of UOA in the more complex group (17 cases, 14.3%) was significantly higher than in the less invasive group (3 cases, 4.6%) (p = 0.049), with the incidence of readmission as 0%. The perioperative factors significantly associated with UOA were age, more complex surgery, and tourniquet time (p < 0.10 all). However, the multivariate regression analysis revealed that tourniquet time was the only significant predictor for UOA (odds ratio = 1.045, 95% confidence interval = 1.022 to 1.067, p = 0.0001). The optimal cut-off points of tourniquet time for predicting UOA with the highest Youden index in the less invasive and more complex groups were 56 minutes and 107 minutes, respectively.

Conclusion: The UOA after AKAS is more common in more complex surgery compared to less invasive surgery. Many factors—such as patient factors, surgical invasiveness, and tourniquet time—were also significantly associated with the unplanned admission. However, the results from this study showed that, under strict perioperative management protocol, tourniquet time is the only independent predictor for UOA.

Orthopedics

Unplanned overnight admission

Ambulatory knee arthroscopic surgery

Clinical risk factor

Surgical invasiveness

Tourniquet time

Table 1

Categorization of the ambulatory arthroscopic knee surgery based on the surgical invasiveness
	Categories of surgical invasiveness
	Less invasive	More complex
Example of cases	Knee arthroscopy with:	Knee arthroscopy with:
	Debridement	ACL reconstruction and/or other ligament reconstruction (PCL, MCL, LCL)
	Synovectomy	Posterior oblique ligament or posterolateral corner reconstruction
	Loose bodies removal	Meniscal reconstruction
	Plica resection	Extensive meniscal repair requiring extracapsular suturing
	Meniscal surgery	Proximal/distal patellar realignment
	Meniscal repair	Removal of deeply imbedded hardware
	Removal of superficial hardware
ACL anterior cruciate ligament, PCL posterior cruciate ligament, MCL medial collateral ligament, LCL lateral collateral ligament

Table 2

Demographic data of 184 patients who underwent ambulatory arthroscopic knee surgery
Demographic data	Total (n = 184)
Age, year^◉	33.4 ± 11.5
Male:female^❖	143:41
BMI, kg/m²^◉	25.1 ± 3.5
ASA classification grade 1:2	123:61
Preoperative IKDC score^◉	52.1 ± 14.0
Operation^☐
Meniscus Surgery	51 (27.7)
ACLR alone	29 (15.8)
ACLR with meniscus surgery	90 (48.9)
Other	14 (7.6)
Operation category
Less invasive:More complex	65:119
Tourniquet time, minute^∆	93 (20–163)
Unplanned admission^☐	20 (10.9)
Intolerated pain with NRS ≥ 4	18^a
Significant PONV	1
Severe dizziness and unable to walk	1
Reoperation	1
BMI body mass index, ASA American Society of Anesthesiologist, IKDC international knee documentation committee, ACLR anterior cruciate ligament reconstruction, NRS numeric rating scale, PONV postoperative nausea or vomiting ^◉ value presented as mean ± standard deviation ^❖ value presented as ratio between cases having that condition ^∆ value presented as mediain (range) ^☐ value presented as number of cases (percentage) ^a one case admitted from concomitant intolerated pain and severe dizziness

Table 3

Data comparison between less invasive and more complex surgery
Demographic data	Less invasive group (n = 65)	More complex group (n = 119)	p-value
Age, year^◉	39.5 ± 13.7	30.1 ± 8.4	< 0.001*
Male:female^❖	34:28	106:13	< 0.001*
BMI, kg/m2^◉	25.5 ± 3.8	24.9 ± 3.3	0.228
ASA classification grade 1:2	30:32	91:28	0.0003*
Preoperative IKDC score^◉	53.4 ± 15.5	51.4 ± 13.1	0.346
Tourniquet time, minute^◉	47 (20–130)	103 (20–163)	< 0.001*
Unplanned admission^☐	3 (4.6)	17 (14.3)	0.049*
BMI body mass index, ASA American Society of Anesthesiologist, IKDC international knee documentation committee ^◉ value presented as mean ± standard deviation or median (range) and compared with unpaired t-test or Mann–Whitney U test ^❖ value presented as ratio between cases having that condition and compared with Fisher exact test or chi square test ^☐ value presented as number of cases (percentage) and compared with Fisher exact test or chi square test * Significant difference with p-value < 0.05

Table 4

Multivariate logistic regression, unplanned admissions (n = 184) for ambulatory arthroscopic knee surgery
Variables	UVA			MVA
Variables	OR	(95% CI)	p-value	OR	(95% CI)	p-value
Age	0.947	0.900 to 0.996	0.033^p
Female gender	0.585	0.163 to 2.104	0.412
BMI	1.020	0.893 to 1.166	0.768
ASA grade 2	0.643	0.222 to 1.860	0.415
Preoperative IKDC score	0.986	0.952 to 1.021	0.422
More complex surgery category	3.444	0.970 to 12.232	0.056^p
Tourniquet time	1.045	1.022 to 1.067	0.0001^p	1.045	1.022 to 1.067	0.0001*
^p predictors used for multivariate regression analysis with p-value < 0.10 in univariate analysis * Significant difference with p-value < 0.05

Table 5

Optimal tourniquet time cut-off points for predicting unplanned overnight admission in whole cohort (n = 184), less invasive (n = 65), and more complex (n = 119) groups
Group	TT cut-off points (minute)	Sensitivity*	Specificity*	PPV*	NPV*
Whole cohort (n = 184)	97^a	80.0 (56.3–94.3)	65.9 (58.1–73.1)	22.2 (13.3–33.6)	96.4 (91.1–99.0)
Whole cohort (n = 184)	103^b	75.0 (50.9–91.3)	72.6 (65.1–79.2)	25.0 (14.7 - 37.9)	96.0 (90.8–98.7)
Less invasive group (n = 65)	56^a,b	100.0 (29.2–100.0)	72.6 (59.8–83.1)	15.0 (3.2–37.9)	100.0 (92.1–100.0)
More complex group (n = 119)	103^a	82.4 (56.6–96.2)	57.8 (47.7–67.6)	24.6 (14.1–37.8)	95.2 (86.5–99.0)
More complex group (n = 119)	107^b	76.5 (50.1–93.2)	65.7 (55.6–74.8)	27.1 (15.3–41.8)	94.4 (86.2–98.4)
TT tourniquet time, PPV positive predictive value, NPV negative predictive value * Data presented as value in percentage (95% confidence interval) ^a the cut-off point of tourniquet time yielding at least 80% sensitivity ^b the cut-off point of tourniquet time with the highest Youden index

No competing interests reported.

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Predicting Surgical Factors for Unplanned Overnight Admission in Ambulatory Arthroscopic Surgery of the Knee: A Prospective Cohort in 184 patients

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