Adductor Canal Block Versus Intra-articular Steroid and Lignocaine in Knee Osteoarthritis Pain Management

BACKGROUND Knee osteoarthritis (KOA) pain is major public health issue globally causing locomotor disability affecting around 251 million people worldwide according to the Global Burden of Disease 2010 Study. In Malaysia, KOA prevalence is 10% to 20% of the elderly population and negatively affects physical function especially limitation in walking (22%), carrying objects (18.6%), and dressing (12.8%). Mild to moderate KOA pain is managed with anti-inflammatory drugs and knee replacement surgery is recommended when pharmacotherapy fails. However, 81% of the patients would refrain from undergoing surgery as it is expensive. Currently there is no effective pharmaceutical treatments for KOA pain & functional disability. Most studies with regards to adductor canal block for KOA pain are done in the immediate post-operative period with only 3 studies looking into ACB in the chronic KOA population: 1 case report and 2 retrospective studies. Thus, there is a need for head to head comparison between Adductor Canal Block (ACB) and Intra-Articular Steroid and Lignocaine (IASL).

OBJECTIVES

Primary objective:

• Investigate the reduction in pain score following adductor canal block in comparison to intra-articular steroid and lignocaine in chronic Knee Osteoarthritis (KOA) pain.

Secondary objectives:

• To ascertain the functional improvement following Adductor Canal Block versus Intra-Articular Steroid and Lignocaine for chronic Knee Osteoarthritis (KOA)
• To evaluate the Quality of life improvement following Adductor Canal Block versus Intra-Articular Steroid and Lignocaine for chronic Knee Osteoarthritis

METHOD

A prospective, single blinded interventional study will be conducted in the Rehabilitation Medicine Clinic, University Malaya Medical Center for a duration of 1 year. Eligible subjects will be enrolled from all referrals of chronic knee osteoarthritis, following computer-generated randomization they will be allocated to either Adductor Canal Block (intervention) or Intra-Articular Steroid and Lignocaine (control) groups. The assessor is blinded to the intervention received, which will be performed by an experienced interventionist, not participating in randomization or data collection and analysis. Demographics of participants, duration of symptoms, Numerical Rating Score (NRS) pain score and Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire score will be recorded prior to injection, 1 week, 1 month and 3 months post injection. Mann-Whitney U tests and Chi-Square test of association will be used as appropriate to compare groups at baseline. Numerical Rating Scale (NRS) pre and post intervention will be analyzed using paired t-test. Functional outcome and Quality of Life (QoL) subset of Knee Injury and Osteoarthritis Outcome Score (KOOS) Questionnaire pre and post intervention will be analyzed using paired t-test as well.

Inclusion criteria

• Symptomatic Knee Osteoarthritis according to criteria of American College of Rheumatology

• Antero-medial knee pain of at least 6 months duration
• Matching symptoms with Knee X-ray findings of KOA
• Kellgran-Lawrence staging of 2-4
• Pain score of at least NRS(Numerical Rating Scale) 4/10 during weight bearing

Exclusion criteria

• Presence of other knee diseases such as fracture or rheumatic diseases
• Referred pain from the back suggestive of lumbar radiculopathy
• Previous knee surgery
• Lateral knee pain
• History of knee joint injections (Intra-articular injections or ACB) within 3 months of study
• Neuropathic knee pain
• Unable to give consent