Knee injuries are in general one of the most common types of injuries we see as clinicians, the majority of these suspected to have some form of underlying meniscus pathology in nature.
In the United States alone, arthroscopic partial menisectomies are the most commonly performed orthopaedic surgery with 700, 000 performed annually resulting in estimated direct medical costs of $4 billion. But is surgery the best answer to these types of injuries?
Sihvonen et al. conducted a multicenter, randomized, double-blind, sham-controlled trial to compare outcomes between two groups who presented with suspected medial meniscus injuries. One group received an arthroscopic partial menisectomy, while the other group received a sham surgical procedure.
146 patients were selected for the study between the ages of 35 to 65 years old all of whom had knee symptoms consistent with a degenerative medial meniscus tear and no knee osteoarthritis. Patients were then randomly assigned to either arthroscopic partial meniscectomy or sham surgery. The surgeon asked a research nurse to open an envelope containing the study-group assignment and reveal it to the surgeon; the assignment was not revealed to the patient.
During the arthroscopic partial meniscectomy, the damaged and loose parts of the meniscus were removed. For the sham surgery, a standard arthroscopic partial meniscectomy was simulated and the patient was kept in the operating room for the amount of time required to perform an actual arthroscopic partial meniscectomy.
The primary outcomes were changes in the Lysholm and Western Ontario Meniscal Evaluation Tool (WOMET) scores and in knee pain after exercise at 12 months after the procedure. The results of the study showed that outcomes after arthroscopic partial meniscectomy were no better than those after a sham surgical procedure.
Clinical implications for us as clinicians are to encourage and promote conservative management of suspected medial meniscus injuries through both physiotherapy and exercise based treatment. Education also plays a fundamental role in recovery and can easily be done through educating patients and other health care professionals on current evidence based practices.
Surgery Versus Physical Therapy for a Knee Meniscal Tear and Osteoarthritis
This study followed 351 patients 45 years and older, diagnosed with a meniscal tear and mild-to-moderate osteoarthritis of the knee via MRI. 174 patients were randomly assigned to a surgical group, while the remaining 177 patients were assigned to a standardized physical therapy regime. The surgical group protocol involved trimming the meniscus back to a stable rim and removing cartilage and bone fragments, while the physical therapy protocol addressed range of motion exercises, education on pain control, strength, cardiovascular and balance work. The patients were then evaluated at 6 and 12 months via the physical function score; the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Patients were given the option to cross over to the surgical group at any time throughout the study.
Outcomes at 6 and 12 months:
- No significant difference in WOMAC function scores between groups at 6 months
- No signigicant differences in KOOS pain scores between groups at 6 months
- No significant difference in WOMAC function scores between groups at 12 months
- No signigicant differences in KOOS pain scores between groups at 12 month
- There was a 30% rate of crossover from the Physical Therapy group to the surgical group at the 6 month mark
The authors conclude that symptomatic patients with a meniscal tear and imaging evidence of a mild-to-moderate osteoarthritis who were assigned to either surgery or physical therapy did not differ significantly in their improvements in functional status and pain levels. Having a meniscal tear does not automatically mean that a client is a surgical candidate, but clinically is more likely when they have blocked ROM and are non responsive to treatment.
Healing Knee Injuries After Surgery
Post operative approaches to a meniscal repair or partial meniscectomy are fairly well established and come with high success rates.
However, within the Canadian healthcare system, the wait times for those surgeries are long and development of co-morbidity is common.
This wait may be compounded if the initial treating/assessing professional is not quick to identify those who will require surgery vs those who will respond to conservative management. Early identification may avoid having those who are capable of conservative rehabilitation filling the schedules of surgeons, thus opening the space for those unlikely to respond without the surgical approach.
Function of a meniscus:
- Load transmission
- Increase joint contact area
- Contribute to joint stability
- Prevention of soft tissue impingement
- Proprioception
- It is because of the above list that preservation of the whole meniscus is so crucial.
- Blood supply:
It is well known that much of the meniscal tissue is not vascular. The lateral meniscus is only vascular in the outer 10-25% and the medial in the outer 10-30%.
The inner avascular portions of each meniscus derive nutrition from the synovial fluid through cyclical compression/decompression, i.e. movement.
References:
Karachalios T, Hantes M, Zibis AH, Zachos V, Karantanas A, Malizos KN. Diagnostic Accuracy of a New Clinical Test (the Thessaly Test) for Early Detection of Meniscal Tears. Journal of Bone and Joint Surgery. 2005; 87 (5). 955-962
Sihvonen, R., Paavola, M., Malmivaara, A., Itala, A., Joukainen, A., Nurmi, H. et al, Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. N Engl J Med. 2013;369:2515–2524.
Katz et al., Surgery versus Physical Therapy for a Mensical Tear and Osteoarthritis. The New England Journal of Medicine April 2013. Retrieved from nejm.org.
