6-year follow-up of 84 patients with cartilage defects in the knee

Figures & data

Flow chart showing the selection of patients from the baseline study to the follow up study.

Table 1. Baseline characteristics of patients with knee cartilage defects. Patients were grouped based on the types of procedures performed

	Subgroup 1	Subgroup 2	Subgroup 3	Subgroup 4	All patients
Cartilage repair: ^a	No	No	Yes	Yes
Ligament/meniscus surgery:	No	Yes	No	Yes
	(n = 25)	(n = 39)	(n = 21)	(n = 13)	(n = 98)^b
Baseline characteristics: mean (SD)
Age at start of symptoms	25 (10)	31 (11)	25 (11)	32 (8.9)	28 (11)
Age at baseline	28 (9.4)	35 (9.4)	30 (10)	35 (8.6)	32 (9.7)
BMI at baseline	24 (4.4)	25 (3.8)	24 (3.3)	26 (4.5)	25 (3.9)
Females/males	12/13	14/25	8/13	4/9	38/60
Area of cartilage defect^c (no. of patients)
< 1 cm^2	3	7	0	1	11
1–2 cm^2	8	18	6	0	32
2–4 cm^2	6	6	6	6	24
> 5 cm^2	8	8	9	6	31
Total	25	39	21	13	98
Location of cartilage defects^d (no. of defects)
Lateral femoral condyle	5	5	2	5	17
Medial femoral condyle	9	21	17	8	55
Lateral tibial condyle	4	5	2	0	11
Medial tibial condyle	4	2	0	2	8
Patella	10	14	3	1	28
Total	32	47	24	16	119 ^e

^a Cartilage surgery was defined as: an autologous chondrocyte implantation (with a preceding biopsy), an osteochondral cylinder transfer, a microfracture repair, or fixation of osteochondral fragment.

^b All patients fulfilling the inclusion criteria were included in the table (n = 98). Of these, 2 had died, 12 were lost to follow-up, and 84 were included in the final follow-up.

^c In patients with more than one defect, the areas given represent the sum of the areas.

^d All injuries were rated as grade 3 or 4 on the International Cartilage Repair Society scale.

^e Some patients had more than one defect; thus, the total number of defects exceeded the number of patients.

Table 2. The numbers of patients with knee cartilage defects who underwent the procedures shown. Patients were grouped based on the types of procedures performed at baseline. In some cases, more than one procedure was performed in a single knee; thus, the number of procedures exceeds the number of patients

	Subgroup 1			Subgroup 2			Subgroup 3			Subgroup 4			All patients
Cartilage repair: ^a	No			No			Yes			Yes
Ligament/meniscus surgery:	No			Yes			No			Yes
	(n = 25)			(n = 39)			(n = 21)			(n = 13)			(n = 98) ^b
Time of procedures: ^c	B	BL	A	B	BL	A	B	BL	A	B	BL	A	B	BL	A
Cartilage repair:
Microfracture	1						1	11	1	1	10	2	3	21	3
Osteochondral cylinder transfer			1					2	1					2	2
Biopsy preceding ACI ^d			1			1		4	1		3	1		7	4
Fixation of osteochondral fragment								4						4
Other procedures:
Diagnostic arthroscopy	6	13	3	7	6		9			2			24	19	3
Debridement of cartilage injury		7	1		3	1			3			1		10	6
Ligament reconstruction	1			2	10	1	1			2	2	2	6	12	3
Meniscal resection	1			7	24	2			2	1	5		9	29	4
Other	2	5	3			2			1			1	2	5	7
No information	3			2									5

^a Cartilage repair was defined as: an autologous chondrocyte implantation (with a preceding biopsy), an osteochondral cylinder transfer, microfracture, or fixation of osteochondral fragment.

^b All patients fulfilling the inclusion criteria were included in the table (n = 98). Of these, 2 had died, 12 were lost to follow-up, and 84 were included in the final follow-up.

^c The time the procedures were performed, expressed relative to the baseline assessment. B: before baseline; BL: at baseline; A: after baseline (during follow-up).

^d ACI: autologous chondrocyte implantation.

Table 3. Knee function assessments based on ICRS questionnaires at baseline and follow-up. Patients were grouped based on the types of procedures performed. Values indicate the numbers of patients in each subgroup who agreed with the corresponding item

	Subgroup 1		Subgroup 2		Subgroup 3		Subgroup 4		All patients
Cartilage repair: ^a	No		No		Yes		Yes
Ligament/meniscus surgery:	No		Yes		No		Yes
	(n = 19/25)		(n = 35/39)		(n = 18/21)		(n = 12/13)		(n = 84/98) ^b
	BL ^b	FU ^b	BL	FU	BL	FU	BL	FU	BL	FU
Functional level
I can do everything I want do with my knee	1	6	0	6	0	4	0	1	1	17
I can do nearly everything I want to do with my knee	4	6	5	19	2	8	1	4	12	37
I am restricted and a lot of things that I want to do with my knee are not possible	8	5	20	10	10	6	7	4	45	25
I am very restricted and I can do almost nothing with my knee without severe pain and disability	9	2	11	0	7	0	4	3	31	5
Total	22	19	36	35	19	18	12	12	89	84
P-value (Wilcoxon test)	0.05		< 0.001		0.002		0.096		< 0.001
Activity level
Are you a highly competitive sportsman/sportswoman?	3	1	9	4	6	1	6	2	24	8
Are you well trained and frequently participate in sport?	10	5	14	9	5	6	1	2	30	22
Participate in sport sometimes	8	10	10	17	5	9	4	5	27	41
Never participate in sport	2	3	3	4	4	2	2	3	11	12
Total	23	19	36	34	20	18	13	12	92	83
P-value (Wilcoxon test)	0.05		0.03		0.2		0.2		0.001
Patient's rating of knee function in comparison with the contralateral knee
90–100%	1	8	1	18	1	7	0	4	3	37
70–90%	5	4	10	15	3	7	0	3	18	29
40–70%	8	4	19	2	10	1	9	2	46	9
0–40%	9	2	5	0	5	2	3	1	22	5
Total	23	18	35	35	19	17	12	10	89	80
P-value (Wilcoxon test)	0.009		< 0.001		0.009		0.03		< 0.001
VAS Pain ^c
Mean values	56	34	44	24	51	32	46	31	48	29
SD	23	29	21	19	23	23	24	23	22	23
Change in VAS pain	22		21		19		15		20
SD	38		25		13		25		25
95% confidence intervaI	0.4–44		12–30		12–26		-2.6–33		14–26
P-value (paired t-test)	0.05		< 0.001		< 0.001		0.09		< 0.001

^a Cartilage repair was defined as: an autologous chondrocyte implantation (with a preceding biopsy), an osteochondral cylinder transfer, microfracture, or fixation of osteochondral fragment.

^b Refers to the number of patients who attended follow-up (FU) in relation to the number of patients at baseline (BL).

^c VAS: visual analog scale with zero representing a pain-free joint and 100 representing “severe pain”.

Table 6. The numbers of patients with knee cartilage defects graded 0–3 on radiographs at follow-up. Weight bearing radiographs were graded according to Kellgren and Lawrence. Patients were grouped based on the types of procedures performed

	Subgroup 1		Subgroup 2		Subgroup 3		Subgroup 4		All patients
Cartilage repair: ^a	No		No		Yes		Yes
Ligament/meniscus surgery:	No		Yes		No		Yes
	(n = 15/25)		(n = 27/39)		(n = 17/21)		(n = 9/13)		(n = 68/98) ^b
	O ^c	CL^c	O	CL	O	CL	O	CL	O	CL
Grade 0	10	15	8	22	8	15	3	5	29	57
Grade 1	2		9	4	6		3	1	20	5
Grade 2	1		8	1	3	2	2	1	14	4
Grade 3	2		2				1	2	5	2
P-value ^d	0.04		< 0.001		0.03		0.8		< 0.001

^a Cartilage repair was defined as: an autologous chondrocyte implantation (with a preceding biopsy), an osteochondral cylinder transfer, microfracture, or fixation of osteochondral fragment.

^b Refers to the number of patients with radiographs at follow-up in relation to the number of patients at baseline.

^c O: Operated knee; CL: Contra-lateral knee.

^d Wilcoxon test for difference between operated and contralateral knee