Knee arthroscopy is beneficial to middle-aged patients with meniscal symptoms:

A prospective, randomised, single-blinded study

Håkan Gauffin1, Sofi Tagesson2, Andreas Meunier1, Henrik Magnusson2, Joanna Kvist2

1Orthopaedic Department, University Hospital, Linköping, Sweden.

2Division of Physiotherapy, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.

1. Original protocol, final protocol, summary of changes.

2. Original statistical analysis plan, final statistical analysis plan, summary of changes

Original protocol

The usefulness of knee arthroscopy in middle-aged patients with meniscus symptoms.

Background

Arthroscopy of the knee joint forms a large percentage of operations at the orthopaedic clinic. In young patients this is usually to diagnose trauma that in turn may require treatment, such as cruciate ligament repair, if good knee function is to be restored.

For the middle-aged patient the situation is different. In these patients one often sees slight to moderate knee symptoms after mild trauma or no trauma at all. In an MRI study, a large number of asymptomatic meniscal changes were seen in older patients (Englund et al. 2008). For this reason one may wonder if the meniscal injury per se is the cause of the patient’s problem, or if it is just an incidental finding. Emerging degenerative disease affecting the joint cartilage, meniscus or both, is often seen at arthroscopy. In many cases the patient’s problem gets better or disappears spontaneously.

Arthroscopy implies usually at least a day off work, often several days even if nothing is done during the surgery. This generates costs from being off work and a fall in production.

In a Swedish study on meniscal surgery a significant improvement was seen 3 months after surgery but function was still poorer than in a healthy reference population (Roos et al. 2000). Herrlin et al. (2007), in a study on patients without radiologic arthritis of the knee, were unable to show a greater improvement in symptoms after arthroscopic menisectomy than in patients receiving physiotherapy alone. Unfortunately, approximately half the patients who could have taken part in the study were not included for various reasons. Nor was a drop-out analysis performed.

It is clear that orthopaedic surgeons find it difficult if not impossible to select those middle-aged patients with suspect degenerative meniscus injury who are likely to benefit from arthoscopy.

Primary question

Does arthroscopic surgery in middle-aged patients with meniscal symptoms lead to improvement compared to a control group without surgery?

Hypothesis

Arthroscopic surgery of the knee leads to better results than does conservative treatment in middle-aged patients with meniscal problems (superiority trial).

Material and method

Inclusion criteria

Patients with a knee problem referred to the orthopaedic clinics in Norrköping and Linköping for consideration for arthroscopy because of suspect meniscal damage (a total of 150 patients).

Age 45 – 64 years

X-ray: normal appearance on stress views (Ahlbäck 0), no patella-femoral arthritic changes.

The patient must be able to understand and follow the study instructions/set-up.

All patients are given an appointment at the outpatient clinics in Norrköping and Linköping where the patient is assessed regarding fulfilment of these criteria and absence of exclusion criteria.

Exclusion criteria.

Rheumatic disease

Fibromyalgia

Hip or knee replacement

Neurologic disease including stroke

Contraindication to surgery

Real and frequent locking (>1 per week)

Permanently locked knee

Method

Randomisation at the outpatient visit to either:

  • Arthroscopy within four weeks + a simple training programme demonstrated on one occasion by a physiotherapist. Functional walking test within 2 weeks. Three months access to a gym for training. Unlimited upper body training but leg training restricted to that described verbally and in the written instructions. A training diary is kept.
  • Non-surgical treatment. A simple training programme demonstrated on one occasion within two weeks by a physiotherapist. Functional walking test within 2 weeks. Three months access to a gym for training. Unlimited upper body training but leg training restricted to that described verbally and in the written instructions. A training diary is kept.

i.e. identical management apart from arthroscopy.

At inclusion

  • KOOS index (all 5 domains)
  • Tegner’s activity score (Tegner 1985)
  • EQ5D (necessary for the financial analysis)
  • Symptom debut – how long have you had pain?
  • Previous training and treatment
  • Surgeon’s assessment/history (predictive factors)
  • Age <55 years – yes/no
  • Sudden debut of pain – yes/no
  • Real locking the past month (the knee is locked more than 2 seconds or needs manipulation to loosen it) – yes/no
  • Daily catching – yes/no
  • Positive McMurray – yes/no

Follow-up at 3 and 12 months after randomisation

  • KOOS at 3 and 12 months
  • Global assessment, Tegner’s activity score and functional walking test at 12 months

Patients declining inclusion (drop-out analysis)

  • KOOS and Tegner’s activity score at 12 months

Primary effect variables

Knee score (KOOS = the Knee Injury and Osteoarthritis Outcome Score) filled in by the patient. This comprises 5 domains: pain; symptoms; ADL; sports/recreation; and knee-related quality-of-life. It has been validated for use in Sweden (Roos et al. 1998).

The pain domain is the primary variable. Each and every domain, however, will be compared separately, longitudinally and between groups. The primary effect variable will be analysed according to the “intention to treat” principle.

Secondary effect variables

  • Global assessment (“How much difficulty do you have from your knee compared to one year ago?” –much better/better/no change.)
  • Functional walking test – timed “up and go” i.e. getting up from a chair, walking 3 metres, turn and walking back and sitting down. + Walking speed over 20 metres
  • Sick-leave during the 6-month periods before and after inclusion in the study, and how much it costs + cost of arthroscopy (carried out by CMT)
  • Do any of the factors registered at inclusion (age, sudden debut of pain, real locking last month, daily catching, positive McMurray) predict the result of arthroscopy of the knee?

Power analysis

Analysis shows six alternatives with standard deviations between 10 and 35.

The least detectable difference is set at 10 points (Frobell, Roos et al. 2003)

“Number” is the number of patients in each group.

Standard deviation for KOOS as described in the literature:

Roos et al. 2008

  • Reference group (healthy knee): pain 12, symptoms 11, ADL 12, sports/recreation 22, knee Q-o-L 18
  • After menisectomy: pain 21, symptoms 18, ADL 19, sports/recreation 32, knee Q-o-L 26

Paradowski et al. 2004

  • Patients after menisectomy (143 patients) with and without osteoarthritis: pain 21, symptoms 18, ADL 18, sports/recreation 32, knee Q-o-L 23.

Englund et al. 2001

  • Degenerative meniscus damage, pattialmenisectomy: pain 17, symptoms 13, ADL 15, sports/recreation 32, knee Q-o-L 24.

Since pain is the primary variable where the SD is between 17 and 21 at least 140 patients are required for this study. We have chosen to include 150 patients.

The importance of this study

If one better can predict those middle-aged patients that will benefit from arthroscopy of the knee, then it will be possible, in the future, to avoid subjecting a large number of patients to unnecessary surgery.

Indirectly this implies great savings for the healthcare system and, not least, for the patient since even this simple procedure carries with it a degree of risk for complications.

Patients who are believed will benefit can be given an appointment for surgery at an earlier stage, thus reducing unnecessary discomfort and even the cost of being off-sick.

Final protocol

Summary of changes

Revision February 2010

Patients from Norrköping: no longer included – difficulty in administering physiotherapist contact in Norrköping.

Orthopaedic surgeon’s examination: the McMurray test is no longer used – considered too difficult to interpret results. Does not add anything.

PAS – physical assessment scale is added as an outcome variable. PAS is a better measurement of patients general activity level compared to the Tegner score.

Follow-up and functional measures now more precise: the physiotherapist who gives the instructions on the training programme also performs functional testing at baseline and after 3 months:

  • Passive range of movements – flexion/extension (Wood et al. 2008)
  • Squatting – performe OK/painful/can’t manage
  • Measurement of any swelling
  • Standing up on one leg, max number of correct repetitions (Larsson et al. 2009, Ericsson et al. 2009)
  • Standing on one leg for 30 sec., eyes closed (SOLEC Wood et al. 2008)

Statistical analysis

All statistical analyses were planed from the start of the study and no changes were made later on. The main analysis was done according to “intention-to treat”. In addition, we performed both “as-treated” and “per-protocol” analyses. The results from the “pre-protocol” analyses are not presented in the present paper. These results were similar to the two previous analyses.

  1. Descriptive analyses of all variables, at all follow-ups
  2. Controlling for homogeneity of variance between the surgery and non-surgery groups with the Levene’s test.
  3. Group comparisons with independent students t-test or Pearson’s chi-square or Fisher’s exact test were applicable, at baseline and at 3-months and 12-months follow-up (cross-sectional analyses). Included variables:
  4. Sex, age dichotomised over and under 55, injured side, symptom duration, expectations, sudden onset of pain, daily joint catching, x-ray Kellgren (only baseline)
  5. KOOS, all domains
  6. EQ5D index and VAS
  7. PAS – physical activity scale (not at 3 months)
  8. Symptom satisfaction (not at 3 months)
  9. Functional tests: pain at squatting, 30 sec stair stand test, SOLEC, ROM, swelling (baseline and 3 months)
  10. Amount of training at gym or at home (3 months)
  11. Longitudinal analyses of change in score within each group between baseline and 3 months and baseline and 12 months (independent students t-test or McNemar´s-test were applicable). Included variables:
  12. KOOS, all domains
  13. EQ5D index and VAS
  14. Functional tests: pain at squatting, 30 sec stair stand test, SOLEC ,ROM, swelling (baseline and 3 months)
  15. Between group comparisons in change score (baseline - 3 moths and baseline – 12 months). Paired t-test.
  16. KOOS, all domains
  17. EQ5D index and VAS
  18. General linear model for predictive factors effect on the main outcome (KOOSPAIN). Predictive factors:
  19. Age <55
  20. Sudden onset of pain
  21. Daily joint catching
  22. Joint locking for >2s

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