Partial replacement of the meniscus of the knee using a biodegradable scaffold: consultation document

Interventional procedure consultation document

Partial replacement of the meniscus of the knee using a biodegradable scaffold

Using keyhole surgery to repair damaged knee cartilage with a biodegradable implant

The meniscus is a crescent-shaped cartilage inside either side of the knee. It acts as a shock absorber between the long bones of the leg. It can be damaged by injury or overuse, causing pain, swelling and locking of the knee. In this procedure, a biodegradable implant is placed into the meniscus by ‘keyhole’ knee surgery. The implant works as a scaffold to support re-growth and repair of the damaged meniscus. The aim of the procedure is to relieve pain and restore the mobility of the knee.

The National Institute for Health and Clinical Excellence (NICE) is examining partial replacement of the meniscus of the knee using a biodegradable scaffold and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE’s Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about partial replacement of the meniscus of the knee using a biodegradable scaffold.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

  • comments on the provisional recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence, with bibliographic references where possible.

Note that this document is not NICE’s formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that NICE will follow after the consultation period ends is as follows.

  • The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  • The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the NICE website (

Through its guidance NICE is committed to promoting race and disability equality, equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our interventional procedures guidance. In particular, we aim to encourage people and organisations from groups in the population who might not normally comment on our guidance to do so.

In order to help us promote equality through our guidance, we should be grateful if you would consider the following question:

Are there any issues that require special attention in light of NICE’s duties to have due regard to the need to eliminate unlawful discrimination and promote equality and foster good relations between people with a characteristic protected by the equalities legislation and others?

Please note that NICE reserves the right to summarise and edit comments received during consultations or not to publish them at all where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 20 March 2012

Target date for publication of guidance: July 2012

1   Provisional recommendations

1.1   Current evidence on partial replacement of the meniscus of the knee using a biodegradable scaffold raises no major safety concerns. Evidence for any advantage of the procedure over standard surgery, for symptom relief in the short-term, or for any reduction in further operations in the long-term, is limited in quantity. Therefore, this procedure should only be used with special arrangements for clinical governance, consent and audit or research.

1.2   Clinicians wishing to undertake partial replacement of the meniscus of the knee using a biodegradable scaffold should take the following actions.

  • Inform the clinical governance leads in their Trusts.
  • Ensure that patients understand that there are uncertainties about any possible long-term advantage over other surgical options and that considerable rehabilitation is required after this procedure. Clinicians should provide patients with clear written information. In addition, the use of NICE’s information for patients (‘Understanding NICE guidance’) is recommended (available from [[details to be completed at publication]]
  • Audit and review clinical outcomes of all patients having partial replacement of the meniscus of the knee using a biodegradable scaffold (see section 3.1).

1.3   The procedure should only be carried out by surgeons who are highly experienced in arthroscopic meniscal surgery.

1.4   NICE encourages further research and data collection on partial replacement of the meniscus of the knee using a biodegradable scaffold. This should include clear descriptions of patient selection and adjunctive treatments. Outcome measures should include symptom relief and functional ability in the short-term and the need for further treatment in the longer-term.

2   The procedure

2.1   Indications and current treatments

2.1.1   The menisci are semi-lunar wedge-shaped fibrocartilaginous structures which act as shock absorbers, spreading the load on the articular surfaces of the knee.

2.1.2   The menisci can be damaged (often a tear) as a result of acute injury or degeneration which may cause pain and/or locking of the knee. It is believed that meniscal damage is associated with a higher risk of knee osteoarthritis in the longer-term. Minor meniscal damage can be treated conservatively (including rest and physical therapies). For more severe cases, treatment usually involves removal of the damaged part of the meniscus (partial meniscectomy).

2.1.3   Meniscal repair is possible only in a minority of patients. This depends on the proximity of the damage to the peripheral vascular region of the meniscus (where good blood supply allows meniscal healing), the pattern of the damage and whether there is damage to other knee joint structures.

2.2   Outline of the procedure

2.2.1   Implantation of a scaffold for partial replacement of the meniscus of the knee aims to temporarily replace the damaged meniscus while allowing growth of blood vessels and regeneration of meniscus-like tissue. In the short term the procedure aims to restore the load-bearing and shock-absorbing functions of the damaged meniscus, contributing to pain relief and restoring functional mobility. In the long term it aims to reduce the risk of osteoarthritis and the need for further operations. A strict rehabilitation regime is usually employed after the procedure, which may include several weeks of restricted weight bearing and temporary bracing to limit knee movement.

2.2.2   The procedure may be done with the patient under general or regional anaesthesia. Using an arthroscope, damaged sections of the meniscus are excised, leaving a residual meniscal rim in the vascular zone. The size of the defect is measured and the implant is trimmed to match it. The implant is then introduced into the joint through an arthroscopic cannula and sutured to the remaining meniscal rim. This may require extra skin incisions to provide sufficient access.

2.2.3   The types of scaffolds available for this procedure include those made of synthetic polyurethane and of collagen derived from animal sources.

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at

2.3   Efficacy

2.3.1   Two study arms described in a randomised controlled trial (RCT) of 311 patients reported pain scores as a mean change from baseline (assessed during rest, activities of daily living and at the highest level of activity on a visual analogue scale; 0–100, higher score indicates greater pain). In one study arm with 157 patients (with no prior surgery on the involved meniscus) treated by partial replacement of the meniscus with a biodegradable implant (n = 75) or by partial meniscectomy (n = 82), mean pain scores of 16 and 21, respectively, were reported at a mean follow-up of 59 months (reported as not significant; p-values not reported). The other study arm of 151 patients (with prior surgery on the involved meniscus) treated by the procedure (n = 82) or by partial meniscectomy (n = 69) reported a mean pain score of 18 for both groups at a mean follow-up of 59 months (reported as not significant; p-values not reported).

2.3.2   A case series of 34 patients reported that mean functional scores (measured by the Lysholm scale; 0–100, higher score corresponds to better function) improved significantly from 58 before the procedure to 94 at 2-year follow-up (p < 0.01).

2.3.3   A non-randomised comparative study of 33 patients treated by partial replacement of the medial meniscus (n = 17) or by partial medial meniscectomy (n = 16) reported mean quality of life scores measured by SF-36 physical health and mental health scales (scale of 0–100, higher score indicates better functioning). For the physical health index, scores were 53.9 (SD 4.0) and 44.1 (SD 9.2) for the implant and the partial meniscectomy groups, respectively, at a mean follow-up of 11 years (p = 0.026). For the mental health index, scores were 54.7 (SD 3.8) and 43.8 (SD 6.5) for the implant and the partial meniscectomy groups respectively at mean follow-up of 11 years (p = 0.004).

2.3.4   The RCT of 311 patients reported reoperation rates, defined as an additional surgical procedure (outside the protocol) on the knee as a result of disabling or persistent pain and/or mechanical symptoms that could possibly involve the meniscus. The reoperation rates were 9.5% and 22.7% for the implant and the partial meniscectomy groups, respectively at 5 years (denominators not reported; significance not reported). Reasons for reoperation included pain, swelling and instability.

2.3.5   In a case series of 52 patients, during second-look arthroscopy, integration of the polyurethane scaffold with the native meniscus was reported in all but 1 patient at 12-month follow-up.

2.3.6   The Specialist Advisers noted the following key efficacy outcomes: pain reduction, functional improvement, reduction in risk of further degeneration of the articular cartilage lining of the knee, early failure (further surgery) and early failure (symptoms or patient-related outcome measures).

2.4   Safety

2.4.1   Dislocation of the implant was reported in 1 patient in an RCT of 60 patients (treated by partial replacement of the meniscus with an implant combined with high tibial osteotomy [n = 30] or high tibial osteotomy alone [n = 30]) at 8 to 18 months after surgery (the implant was removed).

2.4.2   Complete resorption of the collagen implant was reported in 1 patient in a case series of 40 patients (timing of assessment was unclear).

2.4.3   Implant failure (defined as infection caused by the collagen implant or mechanical failure of the implant) was reported in 8% (2/25) of the patients in a case series of 25 patients during follow-up of 10 to 13 years. Postoperative infection (unrelated to the polyurethane scaffold) was reported in 1 patient in the case series of 52 patients at 1 week after the index surgery (the scaffold was removed as part of the treatment for the infection).

2.4.4   Swelling, effusion and redness were reported in 4 patients treated by the procedure and in 1 patient treated by partial meniscectomy in the RCT of 311 patients (timing of assessment was unclear; denominator not reported). Knee swelling was reported in 32% (7/22) of the patients in the case series of 25 patients (timing of assessment was unclear; further details not reported).

2.4.5   The Specialist Advisers noted the following key theoretical safety outcomes: reaction to foreign material, lack of repair/healing with subsequent tearing or displacement, infection or standard related risks for any knee surgery operation.

2.5   Other comments

2.5.1   The Committee noted the lack of clear criteria for patient selection for partial replacement of the meniscus of the knee using a biodegradable scaffold. It also noted that there are two main patient groups (younger and older patients) and it considered that the needs and outcomes of these two groups may be different.

3   Further information

3.1   This guidance requires that clinicians undertaking the procedure make special arrangements for audit. NICE has identified relevant audit criteria and is developing audit support (which is for use at local discretion), which will be available when the guidance is published.

3.2   For related NICE guidance see

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

February, 2012

Personal data will not be posted on the NICE website. In accordance with the Data Protection Act names will be anonymised, other than in circumstances where explicit permission has been given.

It is the responsibility of consultees to accurately cite academic work in order that they can be validated.


This page was last updated: 25 July 2012