The number of total knee replacement procedures in treating genu osteoarthritis is still high due to frequent medical therapy and rehabilitation failures. Therefore, it is necessary to have alternative therapies to help reduce osteoarthritis pain, given the risk of surgical therapy that increases with age.

Orthotic Insoles in Genu Osteoarthritis Treatment
Orthotic Insoles
Image source: https://clinicalaserna.es


The use of orthopedic aids, such as orthotic insoles, and knee braces, is reported to be an alternative therapy. Genu osteoarthritis patients can use either of these aids or both at the same time. This article will discuss the role of orthotic insoles in treating osteoarthritis of the genu and their comparison with other orthopedic aids.

Besides relieves pain, the main purpose of using assistive devices is to improve physical function and slow down the effects of further damage to the knee joint.

There are many studies on therapeutic methods in osteoarthritis genu. In general, the goal is to reduce the outer knee's adduction moment, a marker of active stress on the knee joint. Some of the therapeutic methods that have been studied include the use of sole orthoses and knee braces.

The two are often compared to determine which method is best for treating and reducing genu osteoarthritis pain. However, there is still debate as to which method is better used to treat osteoarthritis genu.


What are Orthotic Insoles?

Orthotic insoles are special shoe insoles designs on the outer side (lateral wedge shoe insoles) or inside (medial wedge shoe insoles) that help distribute the body's center of gravity. Thus, it is expected that orthoses insoles can reduce pressure on the knee joint in cases of osteoarthritis of the genu.


The Role of Orthotic Insoles in the Management of Genu Osteoarthritis

The use of orthotic insoles for osteoarthritis management will change the emphasis on the knee joint during walking. The lateral wedge insoles act as a pressure reducer, which reduces the load on the medial knee joint. This section is the part of the knee joint that is often affected and is generally accompanied by patellofemoral joint disorders.

On the other hand, the medial wedge insoles act as a pressure reducer, which reduces the load on the lateral knee joint. Lateral wedge insoles reduce KAM's external motion by 5–6%, as measured by comparing the pressure on the knee joint's medial and lateral compartments.

However, several randomized controlled trials have shown that lateral wedge insoles are no more effective than neutral insoles in reducing osteoarthritis pain. On the other hand, if the pain in osteoarthritis involves interference with the patellofemoral junction, then the pain will worsen if the knee load point is moved laterally.

Therefore, it is concluded that orthoses insoles will reduce pain if the disturbance only involves the knee joint's medial compartment and does not involve the patellofemoral joint.

Studies examining the effectiveness of using lateral wedge insoles in reducing pain in osteoarthritis have shown that the resulting pain reduction effect of using these devices is minimal. This conclusion was made due to the inconsistency of pain reduction on several benchmarks, namely pain monitoring on clinical examination of the knee, knee injury and osteoarthritis outcome score (KOOS), and the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC).

Only a handful of study participants benefited from using this tool. Several studies have reported that the biomechanical response to the use of lateral wedge insoles varies widely.

Although the exact reason isn't known, a study has shown that the degree of stiffness of the foot and ankle joints in some people prevents eversion of the lateral ankle joints. This process will affect the change in pressure on the knee during therapy to have a positive effect.

On the other hand, although the lateral wedge sole is a fairly safe therapy, there are still reports of discomfort in the legs to pain in the back when wearing this tool.


Comparison of Orthotic Insoles and Other Methods in the Management of Genu Osteoarthritis

Most of the studies examining the use of multiple assist devices in osteoarthritis genu compared the use of orthotic insoles and knee braces. The study results concluded that there was a decrease in the visual analog scale (VAS) in patients who wore lateral wedge insoles compared to the group who did not wear Insoles orthoses.

On the other hand, the comparison between the group wearing the lateral wedge sole and the group using the knee brace showed no significant difference between the two on the VAS scores. However, there are still improvements in both groups.

Compared to orthotic soles, the use of a knee brace requires checking the brace's accuracy periodically. Therefore, the wearer of the knee protector should be a highly educated patient. The patient should be provided with information about how to wear the equipment and the purpose of further therapy.

Patients also need to take immediate control when brace adjustments are needed; that's when the knee brace becomes uncomfortable again. Therefore, not all patients can wear knee braces because it can provide poor therapeutic tolerance if not worn properly.


Guidelines Orthotic Insoles in Managing Genu Osteoarthritis

Nonpharmacological management of osteoarthritis still focuses on exercise and weight loss.
The recommendations regarding the use of orthotic insoles for genu osteoarthritis are controversial. The American College of Rheumatology recommends:
  • lateral wedge insoles for medial femorotibial osteoarthritis 
  • medial wedge insoles for osteoarthritis with lateral femorotibial involvement.
On the other hand, the European League Against Rheumatism (EULAR) does not recommend the use of lateral wedge insoles for osteoarthritis genu. The Osteoarthritis Research Society International (OARSI) recommends biomechanical interventions, where insoles can be considered.



Summary
The use of Orthotic insoles is one of the tools in managing osteoarthritis genu that is easily available, cheap, and quite efficient in reducing pain. This modality can be widely applied in developed and developing countries, where TKR is still limited.

In patients with osteoarthritis of the genu medial compartment, lateral wedge insoles may reduce pain than patients without assistive devices.

However, orthotic insoles' effect is small, and most patients do not achieve the desired therapeutic response. The comparison between the use of orthoses insoles and knee braces did not give significantly different results. The two can still be used as options in the management of osteoarthritis genu.

Nonpharmacological management of osteoarthritis focuses more on physical activity and weight loss. Recommendations regarding the use of orthoses insoles as the management of genu osteoarthritis are still controversial.

Because the evidence is not strong enough, and there are still limited data, orthotic insoles should be used as second-line therapy or companion therapy for genu osteoarthritis. The therapeutic decision in osteoarthritis depends on the articulation location, degree of disability, patient preference, and available therapeutic options.


References
1. Felson DT, Parkes M, Carter S, et al. The Efficacy of a Lateral Wedge Insole for Painful Medial Knee Osteoarthritis After Prescreening: A Randomized Clinical Trial. Arthritis & Rheumatology. 2019; 71 (6): p. 908-15. Downloaded from https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.40808.
2. Beaudreuil J. Orthoses for osteoarthritis: A narrative review. Elsevier. 2016. Downloaded from https://www.sciencedirect.com/science/article/pii/S1877065716305310.
3. Duivenvoorden T, Brouwer RW, Raaij TM et al. Braces and orthoses for treating osteoarthritis of the knee. 2015; Diunduh dariDownloaded from https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD004020.pub3/epdf/abstract.
4. Fernandes L, Hagen KB, Bijlsma JWJ, et al. EULAR recommendations for the non-pharmacological core management of hip and knee osteoarthritis. Ann Rheum Dis 2013;72:1125–35.
5. Hochberg MC, Altman RD, Toupin April K, et al. American College of Rheumatology 2012 recommendations for use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip and knee. Arthritis Care Res 2012;64:465–74.
6. McAlindon TE, Bannuru RR, Sullivan MC, et al. OARSI guidelines for the nonsurgical management of knee Osteoarthritis. Osteoarthritis Cartilage 2014;22: 363–88.
7. Mine K, Nakayama T, and Milanese S. The effectiveness of braces and orthoses for knee osteoarthritis patients: A systematic review of Japanese-language randomized controlled trials. 2016. downloaded from https://journals.sagepub.com/doi/abs/10.1177/0309364616640926.