Meniscal injury and destruction is relatively uncommon in young men and women but becomes increasingly common with age. The history of knee injury, knee symptoms and the age at presentation are all important factors when considering likely causation. Where there is a clear temporal link between injury, symptoms and pathological findings then a causal link to the injury may well be likely. Where there was no convincing record of injury or symptoms and pathological findings date from substantially later, then a causal link is unlikely to be found.
Incidence in Military personnel. Military personnel have a small but significant incidence of acute meniscal injury. A US study from 1999-2006 looking at all active duty personnel found an overall incidence of 8.27 per 1000 person-years (95% CI 8.22-8.32), with an incidence rate ration for men of 1.18 (95% CI 1.15-1.20) and an incidence rate ratio for those aged over 40 compared to those under 20 years of 4.25 (95% CI 4.08-4.42) (Jones et al., 2012).
A past history of open meniscectomy carries a substantial increased risk of knee OA long-term. After open meniscectomy in 1973, 123 patients were followed up for 21 years and significant arthritic change was noted in 48% of patients compared to 7% of controls (relative risk 14.0, 95% CI 3.5-121.2) (Roos et al., 1998)
Isolated medial posterior meniscal root tear is associated with incident and progressive medial tibiofemoral cartilage loss. A total of 596 knees were followed up, 33 with isolated medial posterior meniscal root tear, 294 with meniscal tear and no root tear, and 264 with no meniscal or root tear. The frequency of severe cartilage damage was higher in the group with root tear (76.7% vs 19.7%, p<0.0001) (Guermazi et al., 2013).
Meniscal tears and degeneration is a common finding in older adults and is unrelated to symptoms. A study of 991 subjects age 50 to 90 showed that incidental meniscal findings including tears and meniscal destruction were common in this age group. Prevalence ranged from 19% of women aged 50-59 and 56% of men aged 70 to 90. Sixty-one percent of the subjects who had meniscal tears in their knees had not had any pain, aching or stiffness in the previous month (Englund et al., 2008).
Association of knee OA, surgery and amount of meniscus resected. A literature review of knee OA after surgical management of meniscal tears found that OA develops in the knee of patients undergoing surgery in the long term, and there is a strong statistical association with the amount of meniscus removed, the duration of pre-operative symptoms and surgery to the lateral rather than medial meniscus. Minimally invasive procedures seem to reduce the incidence of long-term osteoarthritic changes of the knee compared with more invasive open and or arthroscopic procedures (Papalia et al., 2011).
Risk of OA knee after meniscectomy. A 15-22 year follow up of 317 patients with meniscal resection and no cruciate ligament injury found symptomatic and radiographic knee OA in 27% of operated knees and 10% of control knees (RR 2.6, 95% CI 1.3-6.1). The risk increased with total v partial meniscectomy, femal sex and obesity (obesity OR 2.5, 95% CI 1.1-5.7). Lateral meniscectomy, intraoperative cartilage changes, and degenerative meniscal tear were associated with worse prognosis compared with medial meniscectomy, absence of cartilage changes, and longitudinal tear. (Englund and Lohmander, 2004)
Knee OA and ACL injury. A systematic review in 2009 of prevalence of tibiofemoral joint osteoarthritis more than 10 years after an anterior cruciate ligament injury found reported prevalence of knee osteoarthritis with isolated ACL injury between 0% and 13%, and for those with ACL and additional meniscal injury between 21% and 48%. This suggested that prevalence rates of knee OA after ACL reconstruction reported by previous reviews have been too high. Differences in reported results is in part attributed to the fact that no universal methodological radiologic classification method exists making comparisons between studies difficult (Oiestad et al., 2009).
Medial meniscal injury and meniscectomy after ACL rupture increases risk of OA. A systematic review in 2015 looking at follow-up for longer than two years in ACL injured patients found that medial meniscal injury and meniscectomy after ACL rupture increased the risk of OA development but lateral meniscal injury and meniscectomy after ACL rupture had no relationship with OA development (van Meer et al., 2015).
ENGLUND, M., GUERMAZI, A., GALE, D., HUNTER, D. J., ALIABADI, P., CLANCY, M. & FELSON, D. T. 2008. Incidental Meniscal Findings on Knee MRI in Middle-Aged and Elderly Persons. New England Journal of Medicine, 359, 1108-1115.
ENGLUND, M. & LOHMANDER, L. S. 2004. Risk factors for symptomatic knee osteoarthritis fifteen to twenty-two years after meniscectomy. Arthritis Rheum, 50, 2811-9.
GUERMAZI, A., HAYASHI, D., JARRAYA, M., ROEMER, F. W., ZHANG, Y., NIU, J., CREMA, M. D., ENGLUND, M., LYNCH, J. A., NEVITT, M. C., TORNER, J. C., LEWIS, C. E. & FELSON, D. T. 2013. Medial posterior meniscal root tears are associated with development or worsening of medial tibiofemoral cartilage damage: the multicenter osteoarthritis study. Radiology, 268, 814-21.
JONES, J. C., BURKS, R., OWENS, B. D., STURDIVANT, R. X., SVOBODA, S. J. & CAMERON, K. L. 2012. Incidence and risk factors associated with meniscal injuries among active-duty US military service members. Journal of athletic training, 47, 67-73.
OIESTAD, B. E., ENGEBRETSEN, L., STORHEIM, K. & RISBERG, M. A. 2009. Knee osteoarthritis after anterior cruciate ligament injury: a systematic review. Am J Sports Med, 37, 1434-43.
PAPALIA, R., DEL BUONO, A., OSTI, L., DENARO, V. & MAFFULLI, N. 2011. Meniscectomy as a risk factor for knee osteoarthritis: a systematic review. Br Med Bull, 99, 89-106.
ROOS, H., LAUREN, M., ADALBERTH, T., ROOS, E. M., JONSSON, K. & LOHMANDER, L. S. 1998. Knee osteoarthritis after meniscectomy: prevalence of radiographic changes after twenty-one years, compared with matched controls. Arthritis Rheum, 41, 687-93.
VAN MEER, B. L., MEUFFELS, D. E., VAN EIJSDEN, W. A., VERHAAR, J. A., BIERMA-ZEINSTRA, S. M. & REIJMAN, M. 2015. Which determinants predict tibiofemoral and patellofemoral osteoarthritis after anterior cruciate ligament injury? A systematic review. Br J Sports Med.