Complications and readmissions following outpatient total hip and knee arthroplasty: a prospective 2-center study with matched controls

Figures & data

Table 1. Discharge criteria for discharge on DOS

DOS discharge criteria

•< 500 ml intraoperative blood loss

•Back in ward before 15.00 hours

•Received instruction from physiotherapist and is safely mobilized

•No clinical symptoms of anemia

•Pain < 3 while resting, < 5 during mobilization

•Spontaneous micturition

•Postoperative radiographs performed and approved

•Relatives or friends with patient for initial 24 postoperative hours

•Motivated and accepts same-day discharge

•Can be discharged before 20.00 hours

•Fulfillment of functional discharge criteria (below)

Functional discharge criteria

•Able to get dressed independently

•Able to get in and out of bed

•Able to sit and rise from a chair/toilet

•Independent in personal care

•Mobilized with walker/crutches

•Able to walk > 70 m with walker/crutches

Patient inclusions and exclusions

Table 2. Preoperative characteristics of the total cohort of outpatients and the matched cohorts of outpatients and non-outpatients. Frequency (%) unless otherwise specified

Characteristic	PS-matched outpatients n = 116		PS-matched non-outpatients n = 339		STD ^a
Age, mean (SD)	61	(11)	62	(10.4)	0.09
BMI, mean (SD)	28	(5)	28	(5)	0.01
Hospital					0.2
A	76	(66)	219	(65)
B	40	(35)	120	(35)
Procedure					0.0
THA	70	(60)	205	(61)
TKA	46	(40)	134	(40)
Sex					0.05
Female	47	(41)	147	(43)
Male	69	(60)	192	(57)
Social situation					0.02
Living with others	102	(88)	300	(89)
Living alone	14	(12)	39	(12)
Use of walking aid					0.0
Yes	7	(6)	20	(94)
No	109	(94)	319	(6)
Smoking					0.06
Yes	23	(20)	78	(23)
No	93	(80)	261	(77)
Alcohol > 2 units daily					0.02
Yes	16	(14)	44	(13)
No	100	(87)	295	(87)
Preoperative anemia
Yes	0		0		0.0
No	116	(100)	339	(100)
Pharmacologically treated psychiatric disorder			0.01
Yes	8	(7)	22	(94)
No	108	(93)	317	(7)
Pharmacologically treated pulmonary disease			0.05
Yes	12	(10)	29	(9)
No	104	(90)	310	(91)
Pharmacologically treated cardiac disease			0.01
Yes	8	(7)	22	(7)
No	108	(93)	317	(93)
Type-2 diabetes					0.06
Yes	1	(1)	1	(0)
No	115	(99)	338	(100)
Any anticoagulants					0.03
Yes	6	(5)	21	(6)
No	110	(95)	318	(94)
Previous venous thromboembolic event			0.03
Yes	5	(4)	12	(4)
No	111	(96)	327	(97)
Previous stroke					0.03
Yes	9	(8)	30	(9)
No	107	(92)	309	(91)
Family with venous thromboembolic event			0.03
Yes	8	(7)	20	(6)
No	108	(93)	319	(94)
Hypertension					0.03
Yes	36	(31)	111	(33)
No	80	(69)	228	(67)

a STD: standardized difference; a STD of > 0.1 was chosen as indicative of imbalance.

PS: propensity score. SD: standard deviation. BMI: body mass index. THA: total hip arthroplasty TKA: total knee arthroplasty.

Table 3. Reason for LOS (length of stay) > 4 days for matched patients in the control cohort

Patient no.	Reason for LOS > 4 days
1	No specific reason identified
2	Chest pain on postop day 1 All tests normal
3	Subtrochanteric fracture on postop day 2
4	Paralytic ileus on postop day 3 conservatively treated

Table 4. Readmission within 90 days following surgery for outpatient patients (n = 116)

Complication type	Specific complication (n = 7)		Postoperative day no. for readmission
Infection (n = 1)	Periprosthetic infection	Treated with debridement and irrigation	48
Thromboembolism (n = 2)	Clinical suspicion of DVT	Ruled out by ultrasound	6, 9
Fracture (n = 2)	Periprosthetic fracture due to fall	Revised with revision THA	6
	Periprosthetic fracture without trauma	ORIF with cables	25
Urologic (n = 2)	Post renal kidney failure due to urinary retention	Treated with urinary catheter and fluids	2
	Urinary retention	Treated with urinary catheter	7

Table 5. Readmission within 90 days following surgery for matched patients (n = 339)

Complication type	Specific complication (n = 13)		Postoperative day no. for readmission
Infection (n = 3)	Periprosthetic infections (2)	Treated with debridement and irrigation	14, 58
	Suspicion of superficial wound infection (1)	Treated with antibiotics	17
Thromboembolism (n = 6)	Clinical suspicion of DVT (5)	Ruled out by ultrasound	4, 7, 8, 14, 26
	Clinical suspicion of DVT, confirmed by ultrasound (1)	Treated with anticoagulants	5
Cardiac (n = 1)	Dyspnea, all tests normal. Hemoglobin measured at 9.4 g/dl	Treated with oral iron	9
Gastrointestinal (n = 1)	Abdominal pain due to Ogilvie syndrome		7
Fracture (n = 1)	Fall and contralateral femoral neck fracture		51
Pulmonary (n = 1)	Acute COPD exacerbation		47

COPD = Chronic obstructive pulmonary disease