Microfractures Versus a Porcine-Derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial

Journal Pre-proof Microfractures Versus a Porcine derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial Man Soo Kim, M.D., Churl Hong Chun, M.D., Ph.D., Joon Ho Wang, M.D., Ph.D., Jin Goo Kim, M.D., Ph.D., Seung-Baik Kang, M.D., Ph.D., Jae Doo Yoo, M.D., Ph.D., Je-Gyun Chon, M.D., Myung Ku Kim, M.D., Ph.D, Chan Woong Moon, M.D., Ph.D., Chong Bum Chang, M.D., Ph.D., In Soo Song, M.D., Jeong Ku Ha, M.D., Ph.D., Nam Yong Choi, M.D., Ph.D., Yong In, M.D., Ph.D. PII:

S0749-8063(19)31100-4

DOI:

https://doi.org/10.1016/j.arthro.2019.11.110

Reference:

YJARS 56689

To appear in:

Arthroscopy: The Journal of Arthroscopic and Related Surgery

Received Date: 21 May 2019 Revised Date:

1 November 2019

Accepted Date: 16 November 2019

Please cite this article as: Kim MS, Chun CH, Wang JH, Kim JG, Kang SB, Yoo JD, Chon JG, Kim MK, Moon CW, Chang CB, Song IS, Ha JK, Choi NY, In Y, Microfractures Versus a Porcine derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial, Arthroscopy: The Journal of Arthroscopic and Related Surgery (2019), doi: https://doi.org/10.1016/j.arthro.2019.11.110. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier on behalf of the Arthroscopy Association of North America

Microfractures Versus a Porcine derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial

Man Soo Kim, M.D.1, Churl Hong Chun, M.D., Ph.D.2, Joon Ho Wang, M.D., Ph.D.3, Jin Goo Kim, M.D., Ph.D.4, Seung-Baik Kang, M.D., Ph.D.5, Jae Doo Yoo, M.D., Ph.D.6, Je-Gyun Chon, M.D.7, Myung Ku Kim, M.D.8, Ph.D., Chan Woong Moon, M.D., Ph.D.9, Chong Bum Chang, , M.D., Ph.D. 5, In Soo Song, M.D. 7, Jeong Ku Ha, M.D., Ph.D. 4, Nam Yong Choi, M.D., Ph.D.10, Yong In, M.D., Ph.D.1,

AUTHOR AFFLIATIONS: 1. Man Soo Kim ([email protected]), Yong In ([email protected]) Department of Orthopaedic Surgery, Seoul St. Mary’s Hospital, College of Medicine The Catholic University of Korea, Seoul, Korea

2. Churl Hong Chun ([email protected]) Department of Orthopaedic Surgery, Wonkwang University Hospital, College of Medicine, Wonkwang University, Iksan, Korea.

3. Joon Ho Wang ([email protected].) Department of Orthopaedic Surgery, Samsung Medical Center, College of Medicine, Sungkyunkwan University of School of Medicine, Seoul, Korea.

4. Jin Goo Kim ([email protected]), Jeong Ku Ha ([email protected]) Department of Orthopedic Surgery, Seoul Paik Hospital, College of Medicine, Inje University, Seoul, Korea.

5. Seung-Baik Kang ([email protected]), Chong Bum Chang ([email protected]) Department of Orthopaedic Surgery, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea

6. Jae Doo Yoo ([email protected]) Department of Orthopaedic Surgery, Ewha Womans University Mokdong Hospital, College of Medicine, Ewha Womans University, Seoul, Korea

7. Je-Gyun Chon ([email protected]), In Soo Song ([email protected]) Department of Orthopaedic Surgery, Daejeon Sun hospital, Daejeon, Korea

8. Myung Ku Kim ([email protected]) Department of Orthopaedic Surgery, Inha University Hospital, College of Medicine, Inha University, Incheon, Korea

9. Chan Woong Moon ([email protected]) Department of Orthopaedic Surgery , Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon, Korea

10. Nam Yong Choi ([email protected]) Department of Orthopaedic Surgery, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea

Corresponding author: Yong In, M.D. Department of Orthopaedic Surgery Seoul St. Mary’s Hospital College of Medicine The Catholic University of Korea 222 Banpo-Daero, Seocho-Gu, Seoul, 06591, Korea Phone: 82-2-2258-2838 FAX: 82-2-535-9834 E-mail: [email protected]

Disclaimer: All of authors reported receiving the sponsorship including provision of material (CartifillTM), MRI scans from Sewon Cellontech Seoul, Korea. Sewon Cellontech is a company manufacturing the products of cartilage regeneration and researching their application.

Conflict of interests: The authors declare that they have no conflict of interest.

Acknowledgements: The authors would like to thank Professor Dong Jae Kim (Division of Biostatics, Department of Medical Lifescience, College of Medicine, The Catholic University of Korea) for the statistical analysis and Professor Won Hee Jee (Department of radiology, Seoul St. Mary’s Hospital, , The Catholic University of Korea ), Young Cheol Yoon (Department of radiology, Samsung Medical Center, College of Medicine, Sungkyunkwan University of School of Medicine), Ja Young Choi (Department of radiology , SMG-SNU Boramae Medical Center, Seoul National University College of Medicine), Yeo Ju Kim (Department of radiology, Inha University Hospital, Inha University) for assessment of radiographic evaluation.

IRB approval by IRB of 1. Seoul St. Mary’s Hospital, the Catholic University of Korea Study No. : XC13DSMI0025K 2. Wonkwang University Hospital, Wonkwang University Study No. WKUH1518 3. Samsung Medical Center, Sungkyunkwan University of School of Medicine Study No.: 2013-12094 4. Seoul Paik Hospital, Inje University Study No SIT-2013-424 5. SMG-SNU Boramae Medical Center, Seoul National University College of Medicine Study No 20131107/26-2013-36/112 6. Ewha Womans University Mokdong Hospital, Ewha Womans University Study No 2013-09-001 7. Daejeon Sun hospital Study No 03CAR 8. Inha University Hospital, Inha University Study No 2013-02-002 (MD13-02) 9. Bucheon St. Mary's Hospital, The Catholic University of Korea Study No HC13DSMI0054 10. St. Paul's Hospital, The Catholic University of Korea Study No XC13DSMI0025P

ClinicalTrials.gov ID: NCT02539030

Running title: Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects

Author Contributions Man Soo Kim: Substantial contributions to the conception of the work, the data acquisition, analysis, and the interpretation of data; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Churl Hong Chun: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Joon Ho Wang: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Jin Goo Kim: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Seung-Baik Kang: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Jae Doo Yoo: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Je-Gyun Chon: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content;

final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Myung Ku Kim: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Chan Woong Moon: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Chong Bum Chang: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. In Soo Song: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Jeong Ku Ha: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Nam Yong Choi: Substantial contributions to the design of the work and the data acquisition,; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work. Yong In: Substantial contributions to the conception of the work, the data acquisition, analysis, and

the interpretation of data; Substantial contribution in drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for accuracy and integrity of any part of the work.

1

Microfractures Versus a Porcine derived Collagen-Augmented Chondrogenesis Technique for

2

Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

29

Abstract

30

Purpose: The purpose of this study was to evaluate the clinical efficacy and safety of treating patients with a

31

cartilage defect of the knee with microfractures and porcine-derived collagen-augmented chondrogenesis

32

technique (C-ACT).

33

Methods: One hundred participants were randomly assigned to the control group (n = 48, microfracture) or the

34

investigational group (n = 52, C-ACT). Clinical and magnetic resonance imaging (MRI) outcomes were

35

assessed 12 and 24 months postoperatively for efficacy and adverse events. Magnetic Resonance Observation of

36

Cartilage Repair Tissue (MOCART) assessment was used to analyze cartilage tissue repair. Magnetic resonance

37

imaging (MRI) outcomes for 50% defect filling and Repaired Tissue/Reference Cartilage (RT/RC) ratio were

38

quantified using T2 mapping. Clinical outcomes were assessed using the visual analogue scale (VAS)–pain,

39

VAS–20% improvement, minimal clinically important difference (MCID), patient acceptable symptom state for

40

Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee

41

score.

42

Results: MOCART scores in the investigation group showed improved defect repair and filling (P = 0.0201),

43

integration with the border zone (P = 0.0062) and effusion (P = 0.0079). MRI outcomes showed that the odds

44

ratio (OR) for ≥ 50% defect filling at 12 months was statistically higher in the investigation group (OR = 3.984,

45

P = 0.0377). Moreover, the likelihood of the RT/RC OR becoming ≥ 1 was significantly higher (OR = 11.37, P

46

= 0.0126) in the investigation group. At 24 months postoperatively, the odds ratio (OR) for the VAS–20%

47

improvement rate was significantly higher in the investigational group (OR=2.808, P=0.047). Twenty-three

48

patients (52.3%) in the control group and 35 (77.8%) in the investigation group demonstrated over the MCID of

49

KOOS pain from baseline to 1-year postoperatively with a significant difference between groups (P = 0.0116).

50

Conclusion:

51

cartilage defect of the knee joint.

52

Level of evidence: Level Ⅰ, Multicenter Randomized Controlled Trial

53

Key words: knee; articular cartilage, cartilage defect, microfracture, collagen-augmented chondrogenesis

54

technique, VAS, MCII, MRI, MOCART

In this multicenter randomized trial, the addition of C-ACT resulted in better filling of

55 56 57

Introduction Once injured, cartilage has severely limited capacity and very low intrinsic activity for

1,2

Although many surgical techniques have been developed for cartilage repair,3 the most

58

repair.

59

commonly selected treatment is bone marrow-stimulating techniques, such as microfracture.4,5

60

However, the use of microfracture is restricted because of its known limitations—i.e., it is effective

61

when the patient is <40 years of age, the lesion size is <4 cm2, and the symptom duration is <1 year.4

62

In addition, the long-term follow-up results of microfracture indicate that the clinical outcome

63

gradually deteriorates over time (after 2–3 years) because of tissue degradation.4 The quality of

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cartilage repair is thus unpredictable, with fibrocartilage, forming after microfracture.4 Various

65

supplementary methods have been suggested to remedy the limitations of the microfracture results.3

66

Recently, methods of supplying collagen to reinforce bone marrow stimulation have been investigated

67

to promote tissue healing.6-8

68

Collagen, a group of proteins that together comprise the most abundant protein mass in

69

humans, is a major component of the extracellular matrix and important constituent of articular

70

cartilage.9 Indeed, collagen has frequently been used as a scaffold to promote cartilage repair

71

because of its availability, accessibility and biocompatibility regarding cell attachment and growth.11

72

Atelocollagen (CartiFill; Sewon Cellontech Co. Ltd., Seoul, Korea) is a highly purified porcine-

73

derived type І collagen that has been modified to virtually eliminate the risk of rejection by removing

74

its telopeptides. It has been developed to provide matrix stability and to maintain blood clotting in the

75

defect site, thereby promoting cartilage repair using mesenchymal stem cells.

10

76

The collagen-augmented chondrogenesis technique (C-ACT) is intended to repair cartilage

77

defects and is suggested to be as safe and efficacious as microfracture for treating cartilage defects.6

78

However, the efficacies of the proposed methods are unclear. There have been lack of randomized

79

controlled trials (RCT)6,12,13 and most studies were retrospective.7,14 The purpose of this study was to

80

evaluate the clinical efficacy and safety of treating patients with a cartilage defect of the knee with

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microfractures and porcine-derived C-ACT. We examined two hypotheses: (1) The quality of articular

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cartilage repair of C-ACT would be superior to that of microfracture based on magnetic resonance

83

imaging (MRI) results, and (2) clinical outcomes of C-ACT would be superior to microfracture at 2

84

years postoperatively.

85 86

Methods

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Study population

88

This RCT was conducted at 10 hospitals. This study was approved by the institutional review

89

board of each hospital. All eligible subjects were informed of the standardized information on clinical

90

trials and provided written informed consent. The trial was registered with ClinicalTrials.gov

91

(NCT02539030). Screening and enrollment of patients were performed from July 2013 to September

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2016. Final follow-up was completed in September 2018. Inclusion criteria were age between 15 and

93

65 years old, the presence of a knee cartilage defect (knee osteoarthritis or knee traumatic arthritis),

94

misalignment of the tibia and femur, and/or treatment for such misalignment. Exclusion criteria were

95

a history of the patients or their families suffering from or having suffered from an autoimmune

96

disease or an anaphylactic reaction; sensitivity to transplants and/or porcine protein; currently

97

pregnant or lactating; contraindication to use of a fibrin sealant; previous ligament surgery. A total of

98

102 patients were screened, and 2 patients were excluded according to the criteria. One refused

99

participation, the other had undergone ligament surgery. Thus, 100 patients were randomized to

100

microfracture alone (control group) or C-ACT (investigational group) (Fig. 1).

101

Randomization, performed just before the operation, was achieved using the computerized

102

block randomization allocation method and was set to generate balanced control and investigational

103

groups. In all, 52 patients were assigned to the investigational group and 48 to the control group.

104

Among them, 45 in investigational group and 44 in the control group completed the 24-month follow-

105

up (Table 1). Of the 89 patients who completed 24-month follow-up, 68 were female. High tibial

106

osteotomy (HTO) was performed when correction was necessary due to varus deformity. Twenty-

107

three patients in the control group and 21 patients in the investigation group underwent HTO.

108

Preoperative planning was performed with the Dugdale method,15 and the target point was determined

109

to be the Fujisawa point.16 Kellgren–Lawrence grading was used for evaluation of OA classification.

110 111

Surgical Procedure

112

Twelve surgeons specialized in sports medicine/knee/cartilage restoration procedures with

113

over 5 years of experience participated in the study. Arthroscopic examination and microfracture to

114

stimulate the bone marrow were performed in all patients. The cartilage lesion was debrided to

115

achieve stable cartilage margins along with careful removal of the calcified cartilage layer.

116

Microfracture was performed with the use of commercially available microfracture awls. Release of

117

blood and marrow fat droplets from the microfracture holes was confirmed by eliminating the

118

arthroscopic pump pressure.

119

For C-ACT, a small mini-arthrotomy was required. A syringe was filled with thrombin

120

solution. Then, 0.4 mL of thrombin solution was transferred to a collagen implant syringe and the two

121

materials mixed several times. A 1-mL syringe was filled with 0.9 mL of atelocollagen (CartiFill) and

122

0.1 mL of thrombin (50 IU) mixture. Another syringe was filled with 1 mL of fibrinogen (Greenplast;

123

Green Cross P.D. Co., Yongin, Korea). Two 1-mL syringes were assembled into a Y-shaped mixing

124

catheter connected to a 20-gauge needle. The anteromedial portal was extended to open the joint, and

125

the capsule was retracted using small retractors. Under arthroscopic vision, the intraarticular fluid of

126

the microfractured site was removed with suction, and gauze was applied to achieve a dry field before

127

the application of the atelocollagen. The gel, in a two-way syringe, was slowly applied into the

128

microfractured site. First, an initial atelocollagen layer was produced followed by an additional layer

129

1–2 min later. After 5 min, the stability of the atelocollagen layer was verified by flexing and

130

extending the knee (Fig. 2).6

131 132

Postoperative Rehabilitation

133

The postoperative rehabilitation protocol was identical for the two groups. The protocol,

134

which started on the first postoperative day, included a set of range-of-motion daily exercises using a

135

continuous passive motion machine for 4 weeks (4 times per day for 30 min). Only toe-touch

136

weight-bearing ambulation was allowed until 4 weeks after the operation. Full weight-bearing

137

ambulation was permitted at 6 weeks postoperatively. This standard rehabilitation protocol was used

138

at all surgical centers participating in the study.

139 140

MRI Evaluation

141

Radiological results were obtained to reinforce the objectivity of this clinical trial with

142

regards to determining efficacy. Eighty-seven patients underwent MRI, of whom 53 underwent

143

quantitative T2 MRI 1 year after surgery. Forty-two patients in the control group and 45 patients in

144

the investigation group underwent MRI, of whom 25 in the control group and 28 in the investigation

145

group underwent quantitative T2 MRI 1 year after surgery. MRI observation of cartilage repair

146

(MOCART) scores were assessed 1 year after surgery and structural morphological evaluation of

147

articular cartilage repair was performed in a blinded manner by an independent orthopedic surgeon

148

with sufficient experience (over 5 years) of musculoskeletal MRI.17,18 A MOCART score of 100 was

149

the best possible score, while 0 indicated the worst MRI outcome. Fifty percent defect filling of

150

articular cartilage was considered the reference for assessing the effect of cartilage repair.18-20 T2

151

relaxation time cartilage mapping was used to evaluate the water content of the cartilage and collagen

152

structure.21,22 T2 mapping was validated and sufficiently sensitive to be used as a non-invasive

153

measurement tool for assessing cartilage quality.21,22 Two musculoskeletal radiologists blinded to the

154

study in each hospital evaluated the T2 mapping for articular cartilage repair.

155

The repaired tissue/reference cartilage (RT/RC) ratio was calculated as described by

156

Domayer et al. (T2 ratio = T2 repair tissue/T2 native cartilage).23 The cutoff value for the T2 ratio was

157

set at 1. As previously documented, the neocartilage T2 value can be higher than the reference

158

cartilage because water content temporarily increases with maturation. During the progress of

159

neocartilage development, L2/L1 (neocartilage/reference cartilage), an MRI T2 cutoff of >1 is

160

deemed a positive sign of biochemical and physiological structural change to that of close-to-normal

161

free cartilage.7,24

162 163

Clinical Evaluation

164

Clinical outcomes were evaluated using the 100-mm visual analogue scale (VAS) for pain,

165

the Knee Injury and Osteoarthritis Outcome Score (KOOS),25 and the International Knee

166

Documentation Committee (IKDC) score26 by an independent investigator who was blinded to the

167

study. The primary endpoint was the VAS–pain score. Each score was determined preoperatively and

168

at 12 and 24 months postoperatively. Minimal clinically important difference (MCID) was defined as

169

a patient with at least 20% improvement in the VAS–pain score from baseline to 24 months

170

postoperatively.27 The MCID and patient acceptable symptom state (PASS) for the KOOS and IKDC

171

were also evaluated and compared between two groups.

172

investigators whenever patients regularly visited the outpatient clinic; multicenter data were integrated

173

online.

28

Clinical data were collected by blinded

174 175 176

Safety Evaluation

177

Safety outcomes—subjective and objectively identified symptoms of adverse events—were

178

assessed according to the investigators’ own judgments about the directly related surgical therapeutic

179

intervention. Vital signs and physical examinations were also evaluated to clarify the safety issue.

180 181

Statistical analysis

182

. Estimation of the sample size was calculated for each group with a power of 80%, which is

183

the probability of avoiding a type II error. The alpha level of significance was set at 0.05. The

184

minimum clinically significant difference (MCSD) in the 100-mm VAS, 12 mm difference, was

185

estimated for the responding patients 29. An SD of 19.34 mm on the VAS was estimated from a pilot

186

study. A sample size estimation based on a 2-tailed test was performed using the main outcome

187

parameter. The sample size for 2 groups was calculated using Internet-based computer software

188

(G*Power 3.1.0). Accordingly, a sample size of 42 patients per group was estimated. In addition, a

189

total of 100 patients with knee cartilage defects were required, considering a possible preliminary

190

dropout rate of 15%. Primary clinical efficacy was assessed using per-protocol set (PPS) analysis at

191

12 months with the last observation carried forward to replace missing values. The unpaired t-test and

192

Wilcoxon rank-sum tests were used for numerical variables. A comparison of categorical variables

193

was made using the ߯2 test or Fisher's exact test. Factors analysis in terms of the cartilage defect size

194

(<4 cm2 vs. ≥4 cm2) and the patient’s age (<50 vs. ≥50 years) was performed to determine if these

195

factors affect principal efficacy variables. Logistic regression analysis was employed for factor

196

analysis. Data were expressed as means ± SD. A value of P<0.05 indicated statistical significance.

197 198

Results

199

Demographics and defect data of the patients are summarized in Table 1. There was no

200

significant difference between the investigational and control groups regarding baseline characteristics

201

and cartilage status. MOCART scores at the 1-year follow-up showed significantly greater

202

improvement in the investigation group with regard to the degree of defect repair and filling,

203

integration with the border zone and effusion (P = 0.0201, P = 0.0062 and P = 0.0079, respectively;

204

Table 2). Indeed, ≥ 50% defect filling was observed in 37 patients (41.57%) in the investigation group

205

and 26 (29.21%) in the control group. There was a statistically significant difference between two

206

groups (P = 0.0377; Table 3). OR, a measure of the association between ≥ 50% filling in terms of the

207

MRI result and atelocollagen use, was 3.984-times higher (95% CI 1.277–12.429) in the investigation

208

group, which was a significant difference (P = 0.0132).

209

In terms of postoperative MRI T2 assessment of RT, the T2 value in the investigational

210

group was an average of 32.87±15.71 msec, with the average value in the control group 28.44±13.43

211

msec. There was no statistically significant difference between the two groups. In the postoperative

212

MRI T2 analysis of the RT/RC ratio with a cutoff reference point of 1, nine (17.0%) subjects in the

213

investigational group and one (1.9%) subject in the control group reported an RT/RC ratio of ≥1.

214

There was a significant difference between the two groups (P = 0.0153) (Table 3). The OR (the

215

correlation parameter between atelocollagen use and the RT/RC ratio of ≥1) was 11.37 (95% CI

216

1.322–97.779) times higher in the investigational group with a significant difference (P = 0.0126).

217

Factor analysis showed that there was no statistical correlation between each factor and the efficacy

218

outcomes, showing the superiority of the investigational group over the control group.

219

Compared with baseline, the clinical results of the VAS, KOOS, and IKDC scores showed

220

significant improvement at 12 and 24 months postoperatively in both groups (Table 4). Also, there

221

was no significant difference between the two groups at each time point. The rate of the VAS

222

improvement of >20% from baseline to 24 months after surgery was seen in 38 (42.70%) subjects in

223

the investigational group and 29 (32.58%) in the control group. There was a statistically significant

224

difference in the 100-mm VAS 20% improvement between the two groups (P = 0.0427) . The odds

225

ratio (OR), which is the correlation parameter between the 100-mm VAS 20% improvement rate

226

based on MCID and atelocollagen use (prescribed to the investigational group) at 24 months

227

postoperatively was 2.808 times higher in the investigational group, with statistical significance [95%

228

confidential interval (CI) 1.013–7.779, P = 0.0471]. Twenty-three patients (52.3%) in the control

229

group and 35 (77.8%) in the investigation group demonstrated over the MCID of KOOS pain from

230

baseline to 1-year postoperative with a significant difference between groups (P = 0.0116). Other

231

variables of MCID and PASS for KOOS and IKDC showed no differences (all p > 0.05) (Table 5).

232

Four severe adverse event cases were reported: unexpected hospitalization due to left knee

233

pain and swelling (control group) 2 months postoperatively; metal removed from the left distal tibia

234

(control group) 9 months postoperatively; removal of a urethral caruncle 3 months postoperatively

235

(investigational group); and acute hepatoma 2 months postoperatively (investigational group).

236

However, there were no adverse events that were deemed relevant to the operation the patient had

237

undergone related to this study.

238 239

Discussion

240

The most important finding of this study was that the investigational group showed a

241

superior result in the 100-mm VAS improvement rate analysis at 12 and 24 months postoperatively

242

and a superior filling rate in the cartilage tissues as well as integration with the surrounding tissues.

243

The results of this study provide valuable information about the additional cartilage repair effect of C-

244

ACT after microfractures.

245

In general, studies that compared cartilage repair excluded traumatic arthritis, whereas this study

246

included both traumatic arthritis and osteoarthritis.6,7,30,31 Microfracture has been known to be

247

effective for <4 cm2.4 In this study, the effect of cartilage repair on lesions of various sizes could be

248

evaluated because it included not only <4 cm2 lesions but those >4 cm2. No significant differences in

249

clinical results were observed for patients with lesions of less or more than 4 cm2 using VAS, KOOS,

250

or IKDC. In addition, it would be possible to evaluate the heterogeneous population composition by

251

incorporating the cases where the correction was necessary along with the malalignment. The bias due

252

to this heterogeneous population was reduced through the multicenter randomized controlled trial

253

design with a sufficient sample size. As a result, the demographic data and baseline characteristics

254

could be well controlled in this study.

255

Collagen, the most abundant protein in extracellular matrix (ECM), is to be an important

256

protein whose characteristic molecular (fibrillar) structure is required for extracellular scaffolding.32

257

That is, collagen has important roles in sustaining the biological and structural integrity of ECM and

258

provides physical support to tissues. As collagen is the major structural protein of most hard and soft

259

tissues, it is available from an extensive range of sources including bone, cartilage, tendons,

260

ligaments, blood vessels, nerves and skin.33 Collagen has a porous structure, low immunogenicity,

261

good permeability and excellent biodegradability and biocompatibility, and can functionally regulate

262

the morphology, adhesion, migration and differentiation of cells.34,35 Because of its superior

263

performance and benefits, collagen natural polymers are considered promising biomaterials for

264

scaffolds in tissue engineering. The method of supplying collagen as a healing adjuvant is simple.

265

Introduce a tiny fracture in the bone in the cartilage defect site and apply atelocollagen mixed with

266

fibrin glue.

267

This is a relatively large-scale clinical trial of 100 patients, and the cutoff of the VAS (≥40)

268

was not set as the exclusion criterion at the screening time.31 Therefore, it would be more reasonable

269

to examine the statistical significance of the MCII, which is meaningful in the clinical setting, rather

270

than the superiority test to evaluate the postoperative improvement in VAS.27,36 The MCII was defined

271

as the smallest change that signified an important improvement (alleviation) of the patient’s

272

symptoms, which would be considered a treatment target for the clinically therapeutic response.27,36

273

This has been applied in a way that permits more individualized assessments of relevant treatment

274

efficacy and applicability to patient care.27,36 MCII value was significantly higher in the

275

investigational group than in the control group, which meant that C-ACT significantly improved the

276

VAS compared with that achieved with microfracture.

277

Based on the characteristics of this clinical trial using surgical procedures, the results based

278

on MRI provided an objective evaluation index that excluded the subjectivity of the cartilage repair of

279

the target region.37 We chose 50% of defect filling of articular cartilage as a reference point, except

280

for complete filling in MOCART.18 In other studies, 50% defect filling was suggested as a criterion

281

for evaluating the effect of cartilage repair.19,20 Therefore, our study also used it as a reference point to

282

determine the extent of cartilage defect filling. The rate of defect filling of >50% was significantly

283

higher in the investigational group than in the controls. This characteristic was also found in the

284

MOCART scores. The investigational group showed significantly superior results regarding the

285

degree of defect repair, filling of the defect, and the integration with the border zone, which was the

286

most direct and important factor in determining the effect of cartilage repair.6,19,20 As shown in Fig. 3,

287

the defect was filled in both groups. However, the integration of the surrounding tissues and the

288

adjacent parts could be confirmed by the fact that the investigational group’s integration was excellent,

289

whereas the control group showed some cracks. In addition, it was judged that the peripheral portion

290

of the integration of the chondral defect target region of C-ACT was statistically superior to that of the

291

control group in the MOCART evaluation.

292

T2 mapping was also used in this study to evaluate cartilage repair, which was a validated,

293

effective, noninvasive tool for assessing cartilage repair.37 T2 and T2* mapping was performed to

294

assess the collagen matrix ultrastructure and, in particular, its zonal shape. This zonal structure, as

295

visualized and quantified with increasing T2 or T2* relaxation times from deep to superficial

296

cartilage, can provide clear evidence of a hyaline-like cartilage structure.38,39 Both T2 and T2*

297

mapping have considerable importance for tracking progress after cartilage repair procedures and

298

hyaline-like cartilage repaired tissues with normal or nearly normal collagen matrix appear to have

299

positive predictive values.40 According to previous studies, T2 relaxation time can provide potential

300

clues for the evaluation of hyaline-like cartilage.41 T2 relaxation time values of the repaired tissue

301

after microfracture was lower than that for native cartilage, which meant that the repaired tissue was

302

fibrous cartilage with relatively lower water content and higher collagen type I.42,43 This histological

303

difference was confirmed by the T2 measurements of cartilage repair tissue with a lower global T2

304

value and less zonal variation of T2 after microfracture compared with MACT.43,44 This tendency was

305

also observed in our study. Although there was no statistical difference, T2 values after microfracture

306

were lower than that after C-ACT. Welsch et al.43,44 showed greater T2 values in the cartilage repair

307

tissue using the collagen-based scaffold, which showed that there was a difference in the composition

308

of the repair tissue even 2 years postoperatively. The cartilage repair tissue gradually developed over

309

time to form a collagen network with a zonal composition similar to normal hyaline-like cartilage.43,44

310

Some studies reported that the T2 value of RT might be higher than that of RC as the water content

311

temporarily increases as the maturation process progresses.24 Therefore, the RT/RC MRI T2 cutoff of

312

≥1 was interpreted as a positive signal of biochemical and physiological structural changes that came

313

close to those of normal hyaline cartilage.24 The RT/RC ratios at the MRI T2 cutoff of ≥1 of the

314

investigational group were significantly higher than those of the control group in this study. As a

315

result, the cartilage of the investigational group appeared more closely related to hyaline cartilage than

316

did that of the control group according to MRI. However, a more long-term T2 observation will be

317

needed for serialization of the cartilage maturation stage of the same subjects.

318

An ideal collagen material possesses the triple-helix structure that exists in vivo, lacks

319

immune function and is available in a highly pure state.45 Collagen present in vivo forms a triple-helix

320

structure, which is important as this structure possesses unique biocompatibility features such as

321

tissue structure-supportive cell-activated platelet activation.46 To eliminate the immune function of

322

collagen, atelocollagen, which has the antigenic telopeptide removed at both ends of collagen’s triple

323

helix structure, should be used. Moreover, use of collagen materials with minimal impurities could

324

also minimize the inflammatory response.47 Collagen used in this study was porcine-derived type I

325

collagen, as many previous studies have demonstrated its stability and effectiveness for knee cartilage

326

defects.6,48

327

328

Limitations

329

Our study had several limitations. First, because we evaluated only Korean patients, the demographic

330

characteristics of our study population should be noted before applying it to other populations..

331

Second, the most accurate evaluation method for the repaired tissue is to analyze the histological

332

appearance via actual biopsy.6 Instead, T2 mapping via MRI was used in this study, which is a

333

validated, non-invasive evaluation tool for histological assessment of the repaired tissue.37 Third, the

334

2-year follow-up period was relatively short. A study with a longer follow-up period should be

335

performed to confirm the results of this study. Fourth, this study was a single-blinded rather than

336

double-blinded trial because of procedural differences between two groups, such as the mini-

337

arthrotomy for patients in the investigational (C-ACT) group. Fifth, about half of the C-ACT

338

procedure was performed with HTO, not in isolation. HTO has been established and is frequently

339

performed concurrently with the cartilage procedure to unload the abnormal cartilage of the medial

340

compartment.6 However, it was unclear whether the symptoms alleviation and the improved tissue

341

quality were due to the cartilage repair procedure or HTO. Sixth, multiple observers and multiple

342

assessments at two time points were ideal for evaluation of cartilage repair with MRI. Validation of

343

MOCART and T2 mapping was not performed through inter-observer testing with repeated

344

measurements between the evaluator. Seventh, although the addition of a new control group

345

(microfractures with fibrin and thrombin) might offer more comprehensive understanding of the

346

specific effect of collagen augmentation on cartilage repair, this study of actual patients had

347

limitations in varying the control group. Our future studies will include a control group involving

348

microfractures with only thrombin and fibrinogen for exact evaluation. Eighth, KOOS is the most

349

widely tool for primary end-point analysis of clinical results to evaluate the effects of cartilage

350

regeneration. However, in this study, pain VAS was used as the primary end point.. Finally, previous

351

surgical history of the knee joint might affect postoperative outcomes, but these factors were not

352

clearly considered in this study.

353 354

Conclusion

355 356

In this multicenter randomized trial, the addition of C-ACT resulted in better filling of cartilage defect of the knee joint.

357 358

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359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402

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lesion treatment. J Orthop Surg Res 2015;10:82. Cho HJ, Chang CB, Kim KW, et al. Gender and prevalence of knee osteoarthritis types in elderly Koreans. J Arthroplasty 2011;26:994-999. Kim MS, Kim JH, Koh IJ, Jang SW, Jeong DH, In Y. Is High-Flexion Total Knee Arthroplasty a Valid Concept? Bilateral Comparison With Standard Total Knee Arthroplasty. J Arthroplasty 2016;31:802-808.

512 513 514 515 516

Figure Legends

517 518

Fig. 1. Consolidated Standards of Reporting Trials (CONSORT) flow diagram of the study. C-ACT,

519

collagen-augmented chondrogenesis technique; MRI, magnetic resonance imaging.

520 521

Fig. 2. Surgical procedure (Right Knee). (A) Cartilaginous lesion was debrided to obtain stable

522

cartilage margins along with careful removal of the calcified cartilage layer. (B) Microfracture was

523

performed using commercially available microfracture awls. (C) The gel, atelocollagen, and fibrin

524

mixture was then slowly applied to the defect. (D) The stability was verified by flexing and extending

525

the knee.

526 527

Fig. 3. Representative MRI and T2 images from a 43-year-old woman in the control group (A, B) and

528

a 48-year-old woman in the investigational group (C, D) (Left Knee). Open triangles: reference

529

cartilage; filled triangles: repaired tissue; ovals: fissure between surrounding tissue and adjacent area.

530

MRI scan of a control patient (A) shows a fissure (oval) between the surrounding tissue and adjacent

531

area, whereas the MRI scan of a patient in the investigational group (C) shows that the integration

532

between the surrounding tissue and the adjacent area seems sufficient. T2 mapping results (B, D)

533

show that the defects in both groups were filled with repair tissue (filled triangles). However, the

534

ratios of repair tissue/reference cartilage (RT/RC) ratios were 0.59 in the control group and 1.13 in the

535

investigational group, respectively, which suggests defect filling with fibrotic tissue in the control

536

group and hyaline-like repair tissue in the investigational group.

537 538 539 540 541 542 543 544

Table 1. Demographics and Defect Data of Patients. Control group (n=44) 51.75 ± 8.10 (24 to 63) 13(29.55) 31(70.45) 35/9 64.74 ± 13.73 (45.00 to 126.00) 24.96 ± 3.65 (18.03 to 37.22)

545

Investigational group (n=45) 48.91 ± 10.22 (22 to 65) 18(40.00) 27(60.00) 33/12 66.02 ± 13.15 (45.00 to 93.00) 25.01 ± 2.97 (20 to 33.59)

P Value

Age, y 0.1662 < 50, n (%) 0.3007 ≥ 50, n (%) Sex, female/male, n 0.4901 Body weight, kg 0.6367 BMI, kg/m2 0.7273 Occupation, n(%) Housewife 24(54.55) 18(40.00) 0.3496 White collar job 8(18.18) 7(15.56) Pink collar job 3(6.82) 8(17.78) Blue collar job 5(11.36) 9(20.00) Inoccupation 2(4.55) 3(6.67) Missing 2(4.55) 0 (0.00) Diagnostic classification, n (%) 0.7391 5(11.36) 4(8.89) TA 39(88.64) 41(91.11) OA 0.5822 Kellgren-Lawrence grade, n (%) in OA Grade 1 5(11.36) 10(22.22) Grade 2 18(40.91) 16(35.56) Grade 3 14(31.82) 12(26.67) Grade 4 2(4.55) 3(6.67) Previous surgical history, n (%) Yes 9(20.45) 13(28.89) 0.3564 No 35(79.55) 32(71.11) Femoral tibial angle (pre-op), ° 2.90±2.70 (0.00 to 15.00) 3.04±3.07 (0.00 to 12.00) 0.7670 Defect size, cm2 4.67±2.54 (1.13 to 12.75) 3.98±1.94 (1.50 to 9.42) 0.2134 4 cm2 > 24(54.55) 27(60.00) 0.6030 4 cm2≤ 20(45.45) 18(40.00) 0.8575 ICRS grade 11(25.00) 12(26.67) Grade Ⅲ 33(75.00) 33(73.33) Grade Ⅳ 0.5969 Concomitant surgery using HTO HTO not performed , n (%) 21(47.73) 24(53.33) HTO performed, n (%) 23(52.27) 21(46.67) 0.4845 Concomitant surgery using meniscectomy Partial meniscectomy not performed , n (%) 39(88.64) 42(93.33) Partial meniscectomy performed , n (%) 5(11.36) 3(6.67) a Numerical variables are presented as mean ± SD with range in parentheses. Categorical variables are presented as frequency with

546

percentage in parentheses. Control group: microfracture alone. Investigational group: microfracture and collagen augmentation. BMI,

547

Body Mass Index; OA, osteoarthritis; TA, traumatic arthritis; HTO, high tibial osteotomy; ICRS, International Cartilage Repair Society.

548 549 550 551 552 553 554

Table 2. MOCART Scores at 1 Year Postoperatively in per protocol set Variable

555 556 557 558 559

Total score 1. Degree of defect repair and filling of the defect Complete (on a level with adjacent cartilage) Hypertrophy (over the level of adjacent cartilage) Incomplete (under the level of adjacent cartilage; underfilling) < 50% of adjacent cartilage ≥ 50% of adjacent cartilage Subchondral bone exposed (complete delamination or dislocation and/or loose body) 2. Integration to the border zone Complete (complete integration with adjacent cartilage) Incomplete (incomplete integration with adjacent cartilage) Demarcating border visible (split-like) Defect visible < 50% of the length of the repair tissue ≥ 50% of the length of the repair tissue 3. Surface of the repair tissue Surface intact (lamina splendens intact) Surface damaged (fibrillations, fissures, and ulcerations) < 50% of repair tissue depth ≥ 50% of repair tissue depth or total degeneration 4. Structure of the repair tissue Homogeneous Inhomogeneous or cleft formation 5. Signal intensity of the repair tissue T2-FSE (or TSE) Normal (identical to adjacent cartilage) Nearly normal (slight areas of signal alteration) Abnormal (large areas of signal alteration) 6. Signal intensity of the repair tissue 3D SPGR(Spoiled GRE) Normal (identical to adjacent cartilage) Nearly normal (slight areas of signal alteration) Abnormal (large areas of signal alteration) 7. Subchondral lamina Intact Not intact 8. Subchondral bone Intact Edema 9. Adhesions No Yes 10. Effusion No Yes

Control group n (%) Score 42(100) 45.7 ± 19.9 42 9.6 ± 5.2 5 (11.90) 4 (9.52)

Investigational group n (%) Score 45(100) 50.9 ± 19.8 45 12.1 ± 5.4 9 (20.00) 10 (22.22)

P Value

13 (30.95) 18 (42.86) 2 (4.76) 41 5 (11.90)

5 (11.11) 19 (42.22) 2 (4.44) 43 19(42.22)

0.1256

8.90 ± 3.62

24( 57.14)

16(35.56)

10 (23.81) 2 (4.76) 39 12(28.57)

7(15.56) 1(2.22) 38 18(40.00)

24(57.14) 3(7.14) 40 18(42.86) 22(52.38) 33 5(11.90) 25(59.52) 3(7.14) 25 4(9.52) 19(45.24) 2(4.76) 37 25(59.52) 12(28.57) 40 18(42.86) 22(52.38) 36 32(76.19) 4(9.52) 36 18(42.86) 18(42.86)

6.15 ± 2.92

2.25 ± 2.52

6.06 ± 4.10

6.20 ± 4.15

3.38 ± 2.37

2.25 ± 2.52

4.44 ± 1.59

2.50 ± 2.54

18(40.00) 2(4.44) 43 23(51.11) 20(44.44) 30 2(4.44) 23(51.11) 5(11.11) 26 2(4.44) 19(42.22) 5(11.11) 41 34(75.56) 7(15.56) 43 21(46.67) 22(48.89) 39 36(80.00) 3(6.67) 39 31(68.89) 8(17.78)

11.16 ± 4.06

0.2274 0.0201c

0.0062b

0.0079b

7.11 ± 2.99

0.1473 0.3005

2.67 ± 2.52

0.4455 0.4396

4.83 ± 3.34

0.1990 0.5218

4.81 ± 3.60

0.1745 0.4218

4.15 ± 1.90

0.1185 0.1146

2.44 ± 2.53

0.7319 0.7263

4.62 ± 1.35

0.6209 0.7041

3.97 ± 2.05

0.0079b 0.0073b

a Score values are presented as mean ± SD. Control group: Microfracture alone. Investigational group: Microfracture and collagen augmentation. MOCART, magnetic resonance observation of cartilage repair tissue; FSE, fast spin echo. b Statistically significant difference between the two groups: P < .01 c Statistically significant difference between the two groups: P < .05.

560 561 562 563 564 565 566 567 568 569

Table 3. Post-surgical improvement rate of defect filling using MRI finding and ratio of repair tissue to reference cartilage using MRI T2 mapping. Variable [follow up period]

570 571 572 573 574 575 576 577 578 579 580 581 582 583

Total subject n (%)

Control group n (%)

Investigational group n (%)

P Value 0.0377a

Defect filling (MRI finding) [12 Months]

< 50 %

19 (23.2)

14 (17.1)

5 (6.1)

≥50 %

63 (76.8)

26 (31.7)

37 (45.1)

RT/RC (Repair Tissue / Reference Cartilage) [12 Months]

<1

43 (81.2)

24 (45.3)

19 (35.8)

≥1

10 (18.8)

1 (1.9)

9 (17.0)

RT, repair tissue; RC, reference cartilage. aStatistically significant difference from two group: P < .05.

0.0153a

584 585 586 587 588 589 590 591 592

Table 4. The comparison of patient clinical outcomea.

Control group (N = 44) Treatment group (N = 45) P-value KOOS - pain Control group (N = 44) KOOS Treatment group P-value KOOS - symptom Control group (N = 44) Treatment group P-value KOOS - ADLs Control group (N = 44) Treatment group P-value KOOS - sport/rec Control group (N = 44) Treatment group P-value KOOS - QOL Control group (N = 44) Treatment group P-value Total Control group (N = 44) Treatment group P-value IKDC - pain Control group (N = 44) IKDC (Subjective) Treatment group P-value IKDC - sports/rec Control group (N = 44) Treatment group P-value IKDC - ADLs Control group (N = 44) Treatment group P-value Total Control group (N = 44) Treatment group P-value VAS

593 594 595 596 597 598 599 600

VAS - pain

44 45 44 45 44 45 44 45 44 45 44 45 44 45 44 45 44 45 44 45 44 45

Screening

12 month

24 month

55.1 ± 26.9 58.2 ± 21.8 0.5507 56.2 ± 20.5 53.5 ± 19.1 0.5175 52.0 ± 19.8 52.9 ± 19.6 0.8131 64.3 ± 18.5 62.8 ± 19.8 0.7271 34.9 ± 24.3 35.7 ± 26.6 0.9410 37.7 ± 22.0 34.4 ± 18.1 0.489 54.9 ± 18.2 53.7 ± 18.8 0.7635 51.9 ± 23.7 46.2 ± 20.3 0.2207 46.3 ± 18.4 42.6 ± 23.0 0.3986 41.4 ± 21.3 42.0 ± 25.4 0.9501 47.6 ± 17.9 43.8 ± 19.7 0.3323

21.0 ± 20.7 22.2 ± 24.1 0.9443 74.1 ± 19.0 74.4 ± 16.1 0.8921 68.9 ± 19.5 66.8 ± 18.4 0.6046 78.9 ± 16.2 77.8 ± 15.4 0.6545 45.9 ± 28.3 47.0 ± 26.2 0.8545 54.7 ± 25.3 53.9 ± 23.1 0.8693 70.3 ± 17.6 69.7 ± 16.4 0.9509 78.4 ± 24.9 78.2 ± 25.3 0.9508 57.7 ± 21.2 57.6 ± 19.2 0.9890 64.1 ± 26.3 64.9 ± 24.3 0.9736 65.8 ± 21.2 65.8 ± 19.3 0.9981

21.5 ± 25.9 15.5 ± 21.6 0.4290 77.8 ± 16.1 82.2 ± 11.6 0.3317 72.0 ± 17.3 74.5 ± 18.4 0.5223 83.1 ± 14.7 83.8 ± 12.7 0.9214 56.0 ± 25.2 58.1 ± 24.7 0.6862 61.7 ± 22.3 61.9 ± 25.0 0.8588 75.2 ± 15.5 77.1 ± 14.1 0.6906 82.7 ± 25.1 80.5 ± 23.6 0.5374 63.6 ± 18.5 63.6 ± 19.5 0.9953 72.5 ± 24.4 70.0 ± 25.8 0.5626 71.2 ± 19.9 70.3 ± 18.5 0.6281

P-value for repeated ANOVA <.0001 <.0001

<.0001b <.0001b

<.0001b <.0001b

<.0001 <.0001

<.0001b <.0001b

<.0001b <.0001b

<.0001 <.0001

<.0001b 0.0001b

<.0001b <.0001b

<.0001 <.0001

<.0001b <.0001b

<.0001b <.0001b

<.0001 <.0001

0.0590 0.0230d

<.0001b <.0001b

<.0001 <.0001

0.0011b <.0001b

<.0001b <.0001b

<.0001 <.0001

<.0001b <.0001b

<.0001b <.0001b

<.0001 <.0001

<.0001b <.0001b

<.0001b <.0001b

<.0001 <.0001

0.0023c 0.0001b

<.0001b <.0001b

<.0001 <.0001

<.0001b 0.0002b

<.0001b <.0001b

<.0001 <.0001

<.0001b <.0001b

<.0001b <.0001b

Adjusted P Adjusted P 12 month 24 month

aNumerical variables are presented as mean ± SD. Control group: microfracture alone. Investigational group: microfracture and collagen augmentation. N, subject number; VAS, Visual analog scale; KOOS, Knee osteoarthirtis outcome score; ADLs, Activities of daily living; QOL, Quality of life; IKDC, International Knee Documentation Committee; sports/rec, sports/recreation; CI, Confidence interval. bStatistically significant difference from baseline: P < .001 compared to baseline. cStatistically significant difference from baseline: P < .01 compared to baseline. dStatistically significant difference from baseline: P < .05 compared to baseline.

601 602 603 604 605 606 607 608 609

Table 5. The minimal clinically important difference (MCID) and patient acceptable symptom state

610

(PASS) of patient clinical outcome Variable [follow up period]

611

Total subject n (%)

Control group n (%)

Investigational group n (%)

IKDC total improvement rate (MCID)

< 16.7

28(31.46)

14(31.11)

14(31.82)

[24 Months]

≥16.7

61(68.54)

31(68.89)

30(68.18)

IKDC total (PASS)

< 75.9

48(53.93)

24(53.33)

24(54.55)

[24 Months]

≥75.9

41(46.07)

21(46.67)

20(45.45)

KOOS pain improvement rate (MCID) [24 Months] KOOS pain (PASS)

< 16.6 ≥16.6 < 88.9

31(34.83) 58(65.17) 66(74.16)

10(22.22) 35(77.78) 30(66.67)

21(47.73) 23(52.27) 36(81.82)

[24 Months]

≥88.9

23(25.84)

15(33.33)

8(18.18)

KOOS symptoms improvement rate (MCID)

< 17.4

42(47.19)

19(42.22)

23(52.27)

[24 Months]

≥17.4

47(52.81)

26(57.78)

21(47.73)

KOOS symptoms (PASS)

< 57.1

17(19.10)

7(15.56)

10(22.73)

[24 Months]

≥57.1

72(80.90)

38(84.44)

34(77.27)

KOOS ADL improvement rate (MCID)

< 15.7

38(42.70)

17(37.78)

21(47.73)

[24 Months]

≥15.7

51(57.30)

28(62.22)

23(52.27)

KOOS ADL (PASS)

< 100

84(94.38)

40(88.89)

44(100.00)

[24 Months]

≥100

5(5.62)

5(11.11)

0(0.00)

KOOS Sport/recreation improvement rate (MCID)

< 25.1

55(61.80)

29(64.44)

26(59.09)

[24 Months]

≥25.1

34(38.20)

16(35.56)

18(40.91)

KOOS Sport/recreation (PASS)

< 75.0

59(66.29)

30(66.67)

29(65.91)

[24 Months]

≥75.0

30(33.71)

15(33.33)

15(34.09)

KOOS QOL improvement rate (MCID)

< 18.8

39(43.82)

17(37.78)

22(50.00)

[24 Months]

≥18.8

50(56.18)

28(62.22)

22(50.00)

KOOS QOL (PASS)

< 62.5

41(46.07)

23(51.11)

18(40.91)

[24 Months]

≥62.5

48(53.93)

22(48.89)

26(59.09)

P Value 0.9427

0.9087

0.0116 0.1026

0.3423

0.3895

0.3427

0.0556

0.6033

0.9397

0.2453

0.3344

612 613 614 615 616 617

Control group: microfracture alone. Investigational group: microfracture and collagen augmentation. N, subject number; VAS, Visual analog scale; KOOS, Knee osteoarthirtis outcome score; ADLs, Activities of daily living; QOL, Quality of life; IKDC, International Knee Documentation Committee; sports/rec, sports/recreation

CONSORT Flow diagram Assessed for eligibility N = 102 Excluded N = 2 Inclusion/Exclusion criteria N = 2

Allocation N = 100

Control group

Investigation group

[Microfracture only]

[C-ACT]

N = 48 (100%)

N = 52 (100%)

Drop out

Drop out

N = 4 (8.3%)

N = 7 (13.5%)

Lost to follow- up

n = 3 (6.3%)

Lost to follow- up

n = 2 (3.8%)

Withdrew consent

n = 1 (2.1%)

Withdrew consent

n = 5 (9.6%)

Analyzed

Analyzed

N = 44 (91.7%)

N = 45 (86.5%)

Included MRI result, ·

n = 42 (87.5%)

Included MRI T2 result n = 25 (52.1%)

· Included ·

MRI result,

n = 45 (86.5%)

Included MRI T2 result n = 28 (53.9%)

·

C-ACT, Collagen-Augmented Chondrogenesis Technique; MRI, Magnetic Resonance Imaging

Fig 1. CONSORT (Consolidated Standards of Reporting Trials) flow diagram