Against arthroscopy for DJD of knees

The BMJ just published a systematic review comparing knee arthroscopy versus conservative management in patients with degenerative knee disease (see knee DJD not do arthroscopy bmj2017 in dropbox, or doi:10.1136/bmjopen-2017- 016114), an update of a prior review, adding ten new studies.

Details:

-- 13 RCTs and 12 observational studies were included

-- studies were diverse: the analysis included those with symptomatic degenerative knee disease, defined as persistent knee symptoms that affect quality of life and does not respond to conservative treatment, but with or without osteoarthritis and, in those getting arthroscopic surgery, “including any or all of debridement and/or partial  meniscectomy”.  Those with acute trauma were excluded.

Results:

-- knee arthroscopy led to a very small reduction in pain in the first three months (mean difference 5.4 on 100 point scale), and very small or no pain reduction up to two years (mean difference of 3.1), high-certainty evidence. The MID (minimally important difference) being 12 points.

-- knee arthroscopy led to a very small improvement in function in the short term (4.9 on a 100-point scale) and very small or no improvement at two years (difference of 3.2), moderate-certainty evidence. The MID being 8 points.

-- very low probability of serious complications after knee arthroscopy, low-quality evidence. The most common serious adverse effect was venous thromboembolism, at a rate of 5/1000, followed by infection at 2/1000.

Commentary:

--symptomatic degenerative knee disease is remarkably common after age 45, affecting about 25% of people, from osteoarthritis of the knee joint lining and/or menisci.

--arthroscopic knee surgery for DJD (degenerative joint disease) is the most common ambulatory orthopedic procedure in the US (and 9^th most common of all ambulatory procedures), associated with transient improvement in pain but requiring activity restriction for 2-12 weeks.

--so, this study found  evidence of minimal benefit from knee arthroscopy at 3 months (not considered clinically significant), which decreased further over the next 2 years, for both pain and function.

--one recent study was cited as an impetus for this systematic review, which included 140 adults (mean age 50; duration of pain 15 months). Though 96% did not have definitive radiographic evidence of OA (osteoarthritis), 91% had MRI-documented meniscal degeneration grade 3a or 3b, which is the worst grade. Patients were randomized to exercise therapy alone vs arthroscopic partial meniscectomy (see knee arthritis exercise vs arthroscopy bmj2016 in dropbox, or doi.org/10.1136/bmj.i3740). For the exercise group:  progressive neuromuscular and strength exercises over 12 weeks, 2-3 sessions/week. For those getting surgery: instruction for home-based exercises 2-4x/day to regain knee ROM  and reduce swelling. For the primary outcomes, no difference in pain at 2 years, using the KOOS (knee injury and osteoarthritis outcome score) subscales on pain, other symptoms, function in sports and recreation, and knee related quality of life (also no difference at 3 months; but the exercise group had had greater improvement in all muscle strength variables at 3 months). On secondary analysis the meniscectomy group had lower pain scores at 12 months that was considered clinically significant (though the exercise group had greater muscle strength at that time). [However, this study does not really rule-out the possibility that meniscectomy with aggressive PT afterwards is superior to both of their interventions, since the therapy post-surgery was just the suggestion to do home-based exercises].

so, the current study comes to the same conclusions as prior analyses, but by adding 10 more studies reinforces those conclusions that arthroscopy is not generally indicated in those with degenerative knee disease. And, I think, it does apply well to primary care, since it did not limit patients to specific MRI or xray findings (and I get MRIs of patients with typical chronic knee pain only quite rarely; and in general the utility of xray itself is questioned, since there is a pretty poor correlation with symptoms per the Framingham Study), or even to specific clinical findings, but seems to apply simply to those with undifferentiated chronic knee pain not responsive to conservative treatment, but affecting quality of life.