Interventional procedure consultation document

Arthroscopic trochleoplasty for patellar instability

Stabilising the kneecap using arthroscopic trochleoplasty

The kneecap (patella) lies in a groove (known as the trochlea) on the lower end of the thigh bone (the femur). If this groove is shallow or uneven the kneecap can slide off during movement of the knee: this is called patellar instability. In arthroscopic trochleoplasty, special instruments are inserted through small cuts in the knee and the trochlear groove is made deeper, to prevent the kneecap sliding off.  

The National Institute for Health and Care Excellence (NICE) is examining arthroscopic trochleoplasty for patellar instability 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 arthroscopic trochleoplasty for patellar instability.

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·       The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.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 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, advance equality of opportunity, 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 September 2013

Target date for publication of guidance: 22 January 2014

 

 

 

1                      Provisional recommendations

1.1                  Current evidence on the safety and efficacy of arthroscopic trochleoplasty for patellar instability is inadequate in quantity and quality. Therefore this procedure should only be used with special arrangements for clinical governance, consent and audit or research.

 

1.2                  Clinicians wishing to undertake arthroscopic trochleoplasty for patellar instability should take the following actions:

·      Inform the clinical governance leads in their NHS trusts.

·      Ensure thatpatients understand the uncertainty about the procedure’s safety and efficacy and provide them with clear written information. In addition, the use of NICE’s information for the public [[URL to be added at publication]] is recommended.

·      Audit [URL to audit tool to be added at publication] and review clinical outcomes of all patients having arthroscopic trochleoplasties (see section 7.1).

 

1.3                  Patient selection should be done by surgeons with expertise in managing patellar instability.

 

1.4                  The procedure should be undertaken by surgeons with experience in open trochleoplasty and in arthroscopic procedures on the knee.

 

1.5                  NICE encourages further research into arthroscopic trochleoplasty for patellar instability, including publication of consecutive patient series. Patient selection should be described in detail. Reported outcomes should include functional and quality‑of‑life measures, as well as reoperation rates.

 

2                      Indications and current treatments

 

2.1                  Patellar instability occurs when the patella fails to engage securely in the trochlea at the start of flexion; it slips laterally and either dislocates completely or slips back medially to its correct position as flexion continues. In some patients this happens because the trochlear groove is too shallow or uneven (trochlear dysplasia). 

 

2.2                  Conservative treatment includes physiotherapy and exercises to strengthen the quadriceps. Surgical approaches include direct reconstruction of the dysplastic trochlea or correction of associated factors by procedures such as medial patellofemoral ligament reconstruction. Trochleoplasty aims to reshape the bony anatomy of the trochlea: it may involve deepening the groove or elevating the lateral wall of the trochlea (which should be higher than the medial). Trochleoplasty is usually done as an open procedure, which is associated with risks such as arthrofibrosis and, rarely, infection.

 

3                      The procedure

 

3.1                  Arthroscopic trochleoplasty aims to deepen the trochlea in the same way as open trochleoplasty but with less soft tissue trauma, which should reduce postoperative pain and allow more rapid recovery.

 

3.2                  Arthroscopic trochleoplasty is done with the patient under general or regional anaesthesia. Using an arthroscopic approach, the articular cartilage of the trochlea is raised as a flap. A round burr shaver is then used to deepen the trochlear groove. The articular cartilage is then returned to the deepened groove and fixed in place. The procedure is often done in combination with medial patellofemoral ligament reconstruction.

 

4                      Efficacy

This section describes efficacy 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. The only available literature on efficacy was 1 case series of 31 patients with recurrent patellar dislocation and trochlear dysplasia type B to D.

 

4.1                  A case series of 31 patients reported outcomes for 29 knees with a median follow‑up of 29 months. The median Kujala score (scores range from 0 to 100 with higher scores indicating less severe symptoms) improved from 64 before the procedure to 95 at follow up. The median Tegner score (scores range from 0 to 10 with higher scores indicating higher activity levels) improved from 4 before the procedure to 6 at follow up. The median knee injury and osteoarthritis outcome scores for pain, symptoms, activities of daily living, sport and quality of life improved from 86, 82, 91, 40 and 25 before the procedure to 94, 86, 99, 85 and 75 respectively at follow up (all p values <0.001).

 

4.2                  The case series of 31 patients reported that patients were satisfied with the outcome of the operation for 93% (27/29) of knees.

 

4.3                  The case series of 31 patients reported that 17% (5/29) of knees needed further surgery. Two patients developed symptomatic subluxations 28 months after the procedure and were both treated by medialisation of the tibial tubercle. Three patients had pronounced postoperative anterior knee pain at flexion and had tightness of the lateral retinaculum, indicating lateral hyper pressure syndromes; all were subsequently treated by lateral releases.

4.4                  The case series of 31 patients reported that there were no redislocations over a median follow up of 29 months.

 

4.5                  The specialist advisers listed additional efficacy outcomes as including International Knee Documentation Committee scores, and radiological outcomes such as patellar tilt and sulcus angle.

 

5                      Safety

 

This section describes 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.

 

5.1                  No infections, cartilage flake breakage or necrosis were reported in the case series of 31 patients.

 

5.2                  Suspected infection from the superolateral portal was reported, within 3 months of arthroscopic trochleoplasty, in 1 patient in a case series of 8 patients. This was resolved with oral antibiotic treatment.

 

5.3                  The specialist advisers listed theoretical adverse events as pain, stiffness, persistent instability, chondrolysis, non‑union, the inability to correctly visualise the amount of correction needed, and the inability to securely fix down the flaps to the deepened groove.

 

6                      Committee comments

 

6.1                  The Committee recognised that arthroscopic trochleoplasty is a specialised procedure applicable to only small numbers of patients. The recommendation for use only in research is not intended to obstruct its use by specialists with the skills and experience stipulated in section 1.4, who should audit their results with great care. It is important that outcomes are published to guide the review by NICE and future use of the procedure.

 

7  Further information

 

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

 

7.2   For related NICE guidance see the NICE website.

 

_{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.}

 

 

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

August 2013