Evaluation of the Efficacy of Radiofrequency-Based Debridement vs. Mechanical Debridement for the Treatment of Articular Cartilage Lesions
Phase: NA
Conditions: Articular Cartilage Disorder of Knee
Sponsor: Christopher Kaeding

Study Title: Evaluation of the efficacy of radiofrequency-based 
debridement vs. mechanical debridement for the treatment of 
articular cartilage lesions.
NCT number: TBD
Date of Document: 02-Jul-2018

Study Title: Evaluation of the efficacy of radiofrequency-based debridement vs. mechanical 
debridement for the treatment of articular cartilage lesions. 
Principal Investigator: Christopher Kaeding, MD 
Co-investigator: David Flanigan, MD 
 
1. STUDY OBJECTIVES 
1.1 Study Purpose 
The purpose of this study is to evaluate the changes in clinical and imaging outcomes 
following arthroscopic treatment of chondral lesion(s) by Radiofrequency-Based 
debridement or Mechanical Debridement in subjects 18-50 years of age. 
 
1.2 Primary Objective 
The primary objective is to evaluate the efficacy of Radiofrequency-Based debridement vs. 
Mechanical Debridement for the treatment of articular cartilage lesions. 
 
1.3 Secondary Objective 
The secondary objectives are to evaluate imaging and additional subjective and objective 
clinical outcomes. 
 
2. STUDY ENDPOINTS 
2.1 Primary Endpoint 
The primary endpoint is to evaluate the change in Knee and Osteoarthritis Outcome Scores 
(KOOS) activity subscale at Week 52 post-operative compared to baseline 
2.2 Secondary Endpoints 
 
Change in Visual Analogue Scale (VAS) scores from baseline 
 
Change in International Knee Documentation Committee (IKDC) Subjective Knee 
Evaluation Form scores from baseline 
 
Change in International Knee Documentation Committee (IKDC) Objective Knee 
Examination Form scores from baseline 
 
Change in Marx Activity Rating Scale from baseline 
 
Change in Work Productivity and Activity Impairment Questionnaire for Articular 
Cartilage Knee Injuries V2.0 (WPAI V2.0) from 1 week post-op to 6 weeks post-op 
 
Subject Satisfaction at Week 52 post-op 
2.3 Imaging Endpoints 
 
ICRS grade of chondral lesion at Week 52 post-op 
 
MRI assessment at Week 52 post-op 
 
3. BACKGROUND AND RATIONALE 
3.1 Introduction 

Knee chondral lesions are tremendously common.  Chondral lesions documented in 
arthroscopies in the years 1989-2004 range from 59% to 63% (7).  Outerbridge Grade 2 was the most 
frequent grade of the cartilage lesion at 42% (7).  Arthroscopic chondroplasty allows removal of loose 
and damaged cartilage which minimizes synovial irritation and mechanical impingement (2).  Two 
techniques for chondroplasty are radiofrequency (RF) and mechanical debridement (MD).  
 
A 10-year randomized controlled study by Spahn et al., concluded that bipolar temperature 
controlled RF treatment at 50 degrees seemed superior to mechanical debridement in their short and 
medium term clinical outcomes and the progression of knee osteoarthritis (5).  Subjects in the RF 
treatment group achieved a higher activity level 1 and 4 years after surgery compared to the MD 
treatment group (5).  The time to required revision in the MD treatment group was 62.5 months with a 
rate of revision of 60.0% in comparison to 94.1 months and 23.3% in the RF treatment group (5). 
 
A study by Lotto et al., showed thermal chondroplasty using radiofrequency energy (RFE) 
produced a larger depth of cellular death than mechanical debridement (MD) (3).  Yet, RFE resulted in 
less healthy cartilage removal than MD (3).  Lotto et al.’s results showed greater arthroscopic smoothing 
with less passes using RFE compared to MD (3). 
 
Current safety concerns regarding RF treatment include the possibility that it contributes to the 
development of osteonecrosis.  A prospective clinical trial by Turker et al., found no increase in the 
incidence of subchondral osteonecrosis with the addition of either mechanical or radiofrequency 
chondroplasty during arthroscopic meniscectomy (6).  Similarly, of the 60 patients treated for grade III 
femoral chondral lesions by Barber and Iwasko (1), no osteonecrosis was observed at the 12 month 
postoperative MRI. 
 
A systematic review by Papalia et al. concluded that RFE is efficient and safe for the surgical 
treatment of chondral lesions, specifically Outerbridge Grade 2 and 3 lesions (4).  Grade 4 lesions were 
found to be too advanced to respond positively to debridement (4).  The systematic review of past 
studies comparing RFE to MD found noticeable similarities to aims and design with a lack of 
randomization (4). 
 
Additional randomized controlled studies are needed to prove that radiofrequency-based 
debridement is not inferior to mechanical debridement for the treatment of articular cartilage lesions.  
The primary objective of the proposed study is to evaluate the efficacy of RF debridement vs. MD for 
subjects requiring treatment of multiple chondral lesions in addition to a partial medial meniscectomy.  
Secondary objectives include evaluating imaging and additional subjective and objective clinical 
outcomes. 
 
3.2 Study Device 
The Smith and Nephew WEREWOLF COBLATION System is indicated for all soft tissue types 
in the knee.  The WEREWOLF COBLATION System is a FDA cleared bipolar, radiofrequency 
electrosurgical system designed for use in orthopaedic/arthroscopic surgical procedures. 

 
The WEREWOLF™ Controller and FLOW 50™ Wand obtained FDA 510(k) clearance 
(K162074) on August 22, 2016. Health Canada clearance is pending. The System consists of 
the following components:  
1. A bipolar radiofrequency Controller with Integrated Fluid Outflow Regulator;  
2. A non-sterile, reusable wired Foot Control and Power Cord  
3. Sterile, disposable, single-use COBLATION Wands  
 
3.3 Mechanism of Action 
Smith & Nephew distributes COBLATION devices for ablation, resection, and coagulation of 
soft tissue and hemostasis of blood vessels in arthroscopic and orthopaedic procedures. 
 
The FLOW 50 Wand is powered by the WEREWOLF Controller.  This system uses a controlled 
radiofrequency-based plasma process (with the trademark ‘COBLATION’). In this process, 
radiofrequency energy is used to excite the water molecules in a conductive medium, such 
as an electrolyte (saline) solution, to generate excited radicals within precisely focused 
plasma. The energized particles in the plasma have sufficient energy to break molecular 
bonds (16-18), excising or dissolving (i.e. ablating) soft tissue at relatively low temperatures 
(typically 40ºC to 70ºC). This technology is a radiofrequency-based technique but its 
mechanism of action is a chemical process and not a function of the radiofrequency energy 
itself. 
 
The FLOW 50 Wand utilizes the Ambient™ feature which provides accurate (±3°C) real-time 
temperature monitoring of the intra-articular irrigating fluid.  
 
These devices also provide the capability for hemostasis, typically delivered through devices 
that can also coagulate bleeding vessels. 
 
4. PROCEDURES 
4.1 Research Design 
This is a non-inferiority, prospective, single blinded, randomized, single-center study design 
with enrollment of 82 randomized subjects (to assure 70 subjects complete the study).  The 
sample size of 82 participants was calculated from a power analysis.  The study was 
powered to detect at least a seven point change in KOOS pain score based on achieving 80% 
statistical power to detect a non-inferiority margin.  Study duration will be until the last 
subject enrolled reaches 52 weeks post-operative. 
 
The 82 randomized subjects will be randomized at a 1:1 ratio into the Werewolf Coblation 
wand treatment group or mechanical debridement treatment group.  Subjects will be 
blinded to their treatment assignment until they complete all study visits.  Upon withdraw 
from the study, termination from the study, or new or recurrent symptoms requiring a 
subsequent arthroscopy, the blinded assignment will be revealed to the subject. 

4.2 Subject Recruitment and Screening 
Subjects will be voluntarily recruited from the Principal Investigator or Sub-Investigator 
population and/or referring physicians. 
 
Subjects will be screened to determine if they meet all inclusion and no exclusion criteria.  If 
all entry criteria are accomplished, the subject will be eligible to participate in the study.  
Eligible subjects will be provided an IRB approved Informed Consent Form for review and 
signature.  Each subject will have a physical assessment by the surgeon and will complete all 
patient reported outcomes (KOOS, VAS, IKDC subjective, Marx).  X-rays and MRI will be 
attained if previous imaging is greater than 3 months old. 
 
All potential subjects screened for eligibility will be listed on the electronic Screening and 
Enrollment Log.  The electronic Screening and Enrollment Log will document the date of 
screening, the results of screening, and the primary reason for excluding the subject.  The 
electronic Screening and Enrollment Log will be kept on the research shared drive 
(encrypted and located behind the OSUMC firewall). The log will be password protected. 
 
4.3 Study Duration and Follow-Up 
Study duration will be until the last subject enrolled reaches 52 weeks post-operative.  
Subjects will be assessed pre-operatively and return post-operatively at Day 10, Weeks 6, 
24, and 52.  At follow-up visit Week 24, the subject questionnaires will be administered 
online through RedCap.  At follow-up visits Week 6 and 52, the subject questionnaires will 
be administered in the office.  At each follow up visit, AEs and concomitant medication will 
be reviewed, as applicable.  At week 52 post-operatively, the subjects will complete a MRI 
of the treated knee. 
 
4.4 Measurement/Instrumentation 
The change in the KOOS activity subscale will be the primary study endpoint.  Secondary 
outcomes include time to return to work/activity and time to return to no pain.  Baseline 
MRI will be compared to MRI at 52 weeks to evaluate knee morphology, cartilage signal, 
osteophytes, bone marrow edema, subarticular cysts, effusions and loose bodies.  The 
international cartilage repair score will be used. 
 
4.5 Detailed Study Visits 
Screening 
 
Confirm written informed consent prior to screening procedures 
 
Inclusion/exclusion criteria 
 
Physical assessment by surgeon – IKDC objective 
 
Demographics 
 
Medical and surgical history 

 
X-rays unless provided (must be less than 3 months old) 
 
MRI unless provided (must be less than 3 months old) 
 
Patient reported outcomes 
o KOOS, VAS, IKDC subjective, Marx 
 
Date of surgery 
 
Arthroscopic inclusion/exclusion criteria 
o No articular cartilage lesion present that requires treatment 
o Evidence of previous chondral treatment not noted at screening 
o Chondrocalcinosis 
 
Randomization 
 
Surgery performed 
10 days (7 days-14 days post op) 
 
Explanation of the weekly online data to be collected on RedCap 
o KOOS activity, VAS, return to work/activity (WPAI V2.0).  [To be completed weekly from 
1 week post op to 6  post op] 
 
Physical assessment by surgeon – IKDC objective 
 
Patient reported outcomes 
o KOOS, VAS, IKDC subjective, Marx 
6 weeks (± 5 days) 
 
Physical assessment by surgeon – IKDC objective 
 
Patient reported outcomes 
o KOOS, VAS, IKDC subjective, Marx 
6 months (±14 days)- To be completed in RedCap 
 
Patient reported outcomes 
o KOOS, VAS, IKDC subjective, Marx 
12 months (±28 days) 
 
Physical assessment by surgeon – IKDC objective 
 
Patient reported outcomes 
o KOOS, VAS, IKDC subjective, Marx 
 
X-rays (merchant view, AP and PA Rosenberg)  
 
MRI 
 
4.6 Data Analysis and Study Validity 

We will minimize selection bias by including a consecutive series of eligible cases until the 
sample size is achieved.  Data will be analyzed using standard statistical software, STATA 13 
(College Station, Tx).  Descriptive statistics will be generated for the total sample.  We will 
assess the difference in our primary and secondary outcomes. 
 
 
5 
SELECTION OF SUBJECTS 
Subjects who meet all of the following criteria will be voluntarily recruited by participating 
Investigators: 
 
5.3 Inclusion Criteria 
Subjects MUST meet ALL of the following criteria to be included in the study: 
 
Given written informed consent on the IRB approved consent form specific to the study, prior to 
study participation 
 
18-50 years old 
 
Male or Female 
 
Suspected chondral damage in the following locations where debridement is indicated: 
o Medial femoral condyle 
o Lateral femoral condyle 
o Trochlea 
o Patella 
 
< 30% joint space narrowing as seen on x-ray (merchant view, AP and PA Rosenberg) 
 
1 or more chondral lesion(s) as noted on MRI 
 
Concomitant procedures are allowed unless noted in the exclusion criteria 
 
5.4 Exclusion Criteria: 
 
Previous chondral treatment in the same compartment (prior debridement and lavage 
performed more than three months prior to baseline are acceptable) 
 
Focal chondral defect indicated for concomitant procedures (i.e., microfracture, ACI, MACI, 
OATs) 
 
Concomitant procedures that are not allowed: 
o Lateral retinacular release 
o Excision of ostephytes 
o Subchondroplasty 
o Manipulation under anesthesia 
o ACL reconstruction 
o Quad tendon repair 
o Patellar tendon repair 
o Patellar tendon debridement 
o Multiligament reconstruction 
 
Pregnant and/or intending to become pregnant during this study period  

 
6 
REFERENCES 
1. Barber, F., & Iwasko, N. (2006). Treatment of grade III femoral chondral lesions: Mechanical 
chondroplasty versus monopolar radiofrequency probe. Arthroscopy, 22, 1312-1317.  
2. Grieshober, Jason A., et al. “Debridement of Articular Cartilage.” Sports Medicine and 
Arthroscopy Review, vol. 24, no. 2, 2016, pp. 56–62., doi:10.1097/jsa.0000000000000108 
3. Lotto, Marie L., et al. “Ex Vivo Comparison of Mechanical Versus Thermal Chondroplasty: 
Assessment of Tissue Effect at the Surgical Endpoint.” Arthroscopy: The Journal of Arthroscopic 
& Related Surgery, vol. 24, no. 4, 2008, pp. 410–415., doi:10.1016/j.arthro.2007.09.018. 
4. Papalia, R., Balzani, L., Torre, G., Paciotti, M., Maffulli, N., & Denaro, V. (2016). Radiofrequency 
energy in the arthroscopic treatment of knee chondral lesions: A systematic review. British 
Medical Bulletin, 117, 149-156.  
5. Spahn, G., Hofmann, G., & von Engelhardt, L. V. (2016). Mechanical debridement versus 
radiofrequency in knee chondroplasty with concomitant medial meniscectomy: 10-year results 
from a randomized controlled study. Knee Surg Sports Traumatol Arthrosc, 24, 1560-1568.  
6. Turker, M., Cetik, O., Cirpar, M., Durusoy, S., & Comert, B. (2015). Postarthroscopy osteonecrosis 
of the knee. Knee Surg Sports Traumatol Arthrosc, 23, 246-250.  
7. Widuchowski, W., et al. “Articular cartilage defects: Study of 25,124 knee arthroscopies.” The 
Knee, vol. 14, no. 3, 2007, pp. 177–182., doi:10.1016/j.knee.2007.02.0