2- to 9-year outcome of stemmed total knee arthroplasty

Figures & data

Table 1. Patient characteristics at index surgery

	All	Primary	Revision	p-value
Surgical procedures	65	24	41
Patients	63	23	40
M / F	15 / 48	5 / 18	10 / 30
Mean age (SD)	68 (12)	68 (13)	68 (11)	0.7
BMI, kg/m2 (SD)	29 (5)	30 (5)	29 (5)	0.2
Primary diagnosis
Primary osteoarthritis	42	10	32
Secondary osteoarthritis	20	12	8
Rheumatic disorder	13	6	7
Posttraumatic	7	6	1
Other	3	2	1
Main indication for surgery
Aseptic loosening	23	-	23
Instability	30	24	6
Infection	10	-	10
Other	2	-	2
Type of primary prosthesis before index surgery
Posterior cruciate-retaining	36	-	36
Posterior-stabilized	4	-	4
Unicompartmental	1	-	1
Cemented / Uncemented	40 / 1	-	40 / 1
Type of stemmed TKA at index surgery				0.2
Constrained condylar knee	40	17	23
Rotating-hinge knee	25	7	18
Tibial component
Sleeve	24	7	17
Stem length, mm (SD)	96 (22)	94 (23)	98 (21)	0.2
Stem width, mm (SD)	14 (3)	15 (3)	14 (3)	0.1
Femoral component
Sleeve	24	7	17
Stem length, mm (SD)	126 (25)	129 (24)	124 (25)	0.4
Stem width, mm (SD)	16 (3)	16 (3)	16 (2)	0.3
Patella
Prosthesis	5	-	5 ^a
Lateral release	18	11	7
Quadriceps snip	4	1	3
Tuberositas tibiae osteotomy	3	1	2
Classification of bone defects
Tibia				0.2
0	2	2	-
Type I	20	6	14
Type II	28	12	16
Type III	15	4	11
Femur				0.2
0	2	2	-
Type I	19	7	12
Type II	27	8	19
Type III	17	7	10

^a1 patellar prosthesis from the original TKA was left in place.

Table 2. Patient characteristics at follow-up

	All	Primary	Revision	p-value
Surgical procedures	61 ^a	22	39
Pain, VAS (SD)
Rest	1.6 (2.4)	0.7 (1.9)	2 (2.5)	0.03
Movement	3.3 (3.3)	1.7 (2.5)	4.2 (3.4)	0.009
BMI, kg/m^2 (SD)	29 (6)	30 (7)	29 (6)	0.9
Range of motion, degrees (SD)	102 (21)	107 (12)	100 (24)	0.5
Medial-lateral stability
Stable	51	18	33
Unstable [+]	6	2	4
Missing	4	2	2
Patella				0.03
Tracking	46	20	26
Subluxation	10	-	10
Dislocation	2	-	2
Missing	3	2	1
KOOS (SD)
Pain	64 (28)	76 (24)	58 (28)	0.02
Other symptoms	73 (23)	83 (18)	67 (24)	0.02
Function in daily living	55 (28)	57 (27)	54 (29)	0.7
Function in sports and recreation	14 (30)	22 (35)	10 (17)	0.3
Knee-related quality of life	51 (32)	61 (26)	47 (34)	0.1
EQ-5D (SD)	0.4 (0.4)	0.5 (0.5)	0.4 (0.4)	0.7
Outcome				0.003
Very satisfied or satisfied	47	22	25
Dissatisfied	12	-	12
Missing	2	-	2
Walking aids, clinical improvement	24	8	16	0.7
Walking distance, clinical improvement	25	10	15	0.6

^a Not included are 4 cases in which the prosthesis was removed during follow-up.

Table 3. Survival and failures (n = 65 cases)

	All	Primary	Revision	p-value
5-year survival, %	82	80	83	0.9
95% CI	72–99	62–99	71–99
Failures (reoperations)	12	4	8	0.8
Deep infection	8	2	6
Other	4	2	2

Table 4. Radiographic results for stemmed total knee arthroplasties at follow-up (n = 56 cases)

Radiolucent lines	0 mm	1 mm	2 mm	3 mm
Tibial component
Anterior-posterior view
Medial plateau	42	12	2	-
Lateral plateau	47	9	-	-
Medial stem	49	4	3	-
Lateral stem	50	4	1	1
Lateral view
Anterior plateau	47	6	3	-
Posterior plateau	45	6	5	-
Femoral component
Anterior-posterior view
Medial stem	45	6	4	1
Lateral stem	45	5	6	-
Lateral view
Shield	51	4	1	-
Anterior stem	46	6	3	1
Posterior stem	49	6	1	-