Abstract
Background:
Around 10,000 symptomatic knee articular cartilage injuries requiring repair occur annually in the UK, mostly in people under 35 years of age. Microfracture surgery aims to restore cartilage. Adding microstructural scaffolds made of collagen, may further improve outcomes.
Objectives
To evaluate the clinical and cost effectiveness of microstructural scaffold in patients undergoing microfracture for a symptomatic chondral or osteochondral defect of the knee.
Design:
Multicentre, parallel two-group, superiority randomised controlled trial with blinding of participants, research staff and clinical care teams not involved in the surgery.
Setting
NHS hospitals offering arthroscopic chondral surgery.
Participants
Adults aged 18 years or older with symptomatic chondral or osteochondral defects of the knee on the medial or lateral femoral condyles, trochlea or patella and a chondral/osteochondral lesion measuring no more than 4cm2. Exclusions were: unstable ligamentous injuries or meniscal tears that would not be treated; a knee with defects on the tibial chondral surface, less than 50% native meniscal volume, or requiring realignment surgery/osteotomy; and a lesion previously treated with microfracture.
Interventions
Lesions were debrided and microfracture was performed on the exposed subchondral bone.
Intervention: microfracture of the chondral/osteochondral lesion with insertion of a bilayer collagen matrix microstructural scaffold, fixed with stiches or fibrin glue.
Comparator: microfracture alone.
Post-operative physiotherapy was standardised.
Participants were randomised 1:1 between intervention and control.
Main outcome measures
Primary outcome was the Knee injury and Osteoarthritis Outcome Score at 24 months post-randomisation. Secondary outcomes included International Knee Documentation Committee knee evaluation score, Tegner-Lysholm activity grading scale, EQ-5D-5L, Work Productivity and Activity Impairment, complications and resources use measured at 3, 6, 12 and 24 months.
Results
Twenty-two patients were screened across eight sites, 20 of whom were eligible on screening. Of the 20 patients considered initially eligible, two patients were not interested and one opted for chrondroplasty, the remaining 17 all consented to participate. Between November 2021 and October 2022, 10 participants were randomised, 5 to microfracture and 5 to microfracture with scaffold. Three patients failed the final in-surgery eligibility check (lesions had healed), one decided not to have surgery and three were still waiting when the study was closed. The median age was 38 years and 4 participants were female. Most participants (7) had damage to the lateral femoral condyle and 6 had a medial and/or lateral meniscal tear. All participants received the allocated treatment and are included in the reported results. When a scaffold was used the surgery took on average 10 minutes longer. There were three serious adverse events, knee pain and swelling in one participant, and a suspected anaphylactic reaction in another.
Limitations
SISMIC did not progress beyond the internal pilot phase due to insufficient recruitment. The target number of sites were opened but recruitment was only 42% of the target 24 participants randomised. Insufficient data were collected to answer the research question.
Conclusions
SISMIC was severely impacted by the COVID-19 pandemic, the limited resources available at sites and the reduced elective orthopaedic surgical activity.
Future work
To reflect contemporary practice, we recommend that a future trial evaluates three treatments; chondroplasty, chondroplasty with a microstructural scaffold and autologous chondrocyte implantation.
Trial registration
ISRCTN90992837
Around 10,000 symptomatic knee articular cartilage injuries requiring repair occur annually in the UK, mostly in people under 35 years of age. Microfracture surgery aims to restore cartilage. Adding microstructural scaffolds made of collagen, may further improve outcomes.
Objectives
To evaluate the clinical and cost effectiveness of microstructural scaffold in patients undergoing microfracture for a symptomatic chondral or osteochondral defect of the knee.
Design:
Multicentre, parallel two-group, superiority randomised controlled trial with blinding of participants, research staff and clinical care teams not involved in the surgery.
Setting
NHS hospitals offering arthroscopic chondral surgery.
Participants
Adults aged 18 years or older with symptomatic chondral or osteochondral defects of the knee on the medial or lateral femoral condyles, trochlea or patella and a chondral/osteochondral lesion measuring no more than 4cm2. Exclusions were: unstable ligamentous injuries or meniscal tears that would not be treated; a knee with defects on the tibial chondral surface, less than 50% native meniscal volume, or requiring realignment surgery/osteotomy; and a lesion previously treated with microfracture.
Interventions
Lesions were debrided and microfracture was performed on the exposed subchondral bone.
Intervention: microfracture of the chondral/osteochondral lesion with insertion of a bilayer collagen matrix microstructural scaffold, fixed with stiches or fibrin glue.
Comparator: microfracture alone.
Post-operative physiotherapy was standardised.
Participants were randomised 1:1 between intervention and control.
Main outcome measures
Primary outcome was the Knee injury and Osteoarthritis Outcome Score at 24 months post-randomisation. Secondary outcomes included International Knee Documentation Committee knee evaluation score, Tegner-Lysholm activity grading scale, EQ-5D-5L, Work Productivity and Activity Impairment, complications and resources use measured at 3, 6, 12 and 24 months.
Results
Twenty-two patients were screened across eight sites, 20 of whom were eligible on screening. Of the 20 patients considered initially eligible, two patients were not interested and one opted for chrondroplasty, the remaining 17 all consented to participate. Between November 2021 and October 2022, 10 participants were randomised, 5 to microfracture and 5 to microfracture with scaffold. Three patients failed the final in-surgery eligibility check (lesions had healed), one decided not to have surgery and three were still waiting when the study was closed. The median age was 38 years and 4 participants were female. Most participants (7) had damage to the lateral femoral condyle and 6 had a medial and/or lateral meniscal tear. All participants received the allocated treatment and are included in the reported results. When a scaffold was used the surgery took on average 10 minutes longer. There were three serious adverse events, knee pain and swelling in one participant, and a suspected anaphylactic reaction in another.
Limitations
SISMIC did not progress beyond the internal pilot phase due to insufficient recruitment. The target number of sites were opened but recruitment was only 42% of the target 24 participants randomised. Insufficient data were collected to answer the research question.
Conclusions
SISMIC was severely impacted by the COVID-19 pandemic, the limited resources available at sites and the reduced elective orthopaedic surgical activity.
Future work
To reflect contemporary practice, we recommend that a future trial evaluates three treatments; chondroplasty, chondroplasty with a microstructural scaffold and autologous chondrocyte implantation.
Trial registration
ISRCTN90992837
| Original language | English |
|---|---|
| Journal | Public Health Research |
| Publication status | Accepted/In press - 11 Apr 2025 |
Keywords
- randomised controlled trial
- chondal knee defects
- osteochondal knee defects
- microfracture
- colleagen matrix scaffold
- knee surgery