Lateral epicondylosis, also called tennis elbow or lateral epicondylitis, is a prevalent, painful syndrome of the elbow. It is refractory to conservative treatment measures, including rest, excentric and concentric exercises in approximately 20% of patients after 6 months. Corticosteroid injections can provide relief in the short term. Mini-open surgery may be proposed when the conservative treatment fails and studies have shown an efficacy of 70%. Ultrasound-guided tendon fenestration is a minimally-invasive technique which stimulates the physiological healing mechanisms of the tendon and appears promising for the treatment of chronic tendinopathies. To our knowledge, no studies have compared the US-guided fenestration technique to mini-open surgery for the treatment of chronic lateral epicondylosis.

The primary objective of this pilot study is to compare the efficacy of US-guided fenestration to mini-open surgery to reduce pain and improve functional status in workers suffering from chronic lateral epicondylosis refractory to 6-month conservative treatment.

This is a prospective single-blind randomized pilot study. Sixty-four subjects will be randomized into two intervention groups for treatment either by US-guided fenestration or mini-open surgery. The primary outcome of the study will be the Patient Rated Tennis Elbow Evaluation (PRTEE) score at 6 month post-procedure.

STUDY DESIGN:

Phase II, prospective, two-arm, single-blind randomized controlled study.

SETTING:

Up to 64 patients (56 + 15% loss to follow-up) suffering from chronic lateral epicondylosis will be recruited by one of two orthopedists working in a specialized outpatient clinic, at the Centre Hospitalier de l'Université de Montréal (CHUM), a tertiary care academic center. Ultrasound examination of the elbow will be performed before the interventions.

RANDOMIZATION:

Using a computerized randomization list, the subjects will be randomized into the 2 treatment arms to be treated either by an US-guided tendon fenestration technique or by mini-open surgery. Randomization will be stratified by block sizes of 8.

FOLLOW UP Subjects' follow-up will extend over a period of 12 months - i.e., at 6 weeks and 3, 6 and 12 months post-intervention. The primary outcome will be the PRTEE score. Secondary outcomes will evaluate the impact of each procedure on: Pain-free grip (dynamometer), Medication Quantitative Scale, working activity (QuickDASH general and work modules; RA-WIS), Patient Global Impression of Change and Patient Satisfaction. The ultrasound examination will be repeated at 6 and 12 months. The predictive value of various B-mode parameters, color Doppler and elastography will be explored.

ANALYSIS:

The primary endpoint will be the proportion of subjects in each intervention arm presenting a reduction of at least 11/100 of the PRTEE score at 6 months post-intervention. The Fisher's exact test will be used to compare the proportion of subjects in each treatment group. The primary analysis will follow the intention-to-treat principle. Regarding the secondary endpoints, an ANOVA for repeated measures with two factors (time and group), a Fisher's exact test or a recursive partitioning analysis will be performed as appropriate.

Inclusion Criteria:

• Workers
• Ability to read, understand and answer questionnaires in French or English
• Diagnosis of unilateral, lateral epicondylosis established by an orthopaedist, determined by clinical presentation and pain, ≥ 4/10 on a pain numerical rating scale, on palpation of the region slightly anterior and distal to the lateral epicondyle, exacerbated by the extension of the wrist or the middle finger when the elbow is in extension.
• Chronic epicondylosis, refractory to medical treatment conducted for at least six months, which includes rest and implementation of ergonomics to avoid soliciting the extensor tendons, and at least one of: physical therapy, a rehabilitation program with stretching and / or strengthening exercises, injection treatments (corticosteroids, autologous PRP) or extracorporeal shock waves.

Exclusion Criteria:

• Suspected tumor or infectious etiology
• Injection of corticosteroids during the last 3 months
• Hemorrhagic diathesis; anticoagulation (platelets <50,000, International Normalized Ratio (INR) > 2)
• Local infection
• History of elbow surgery or fracture
• History of inflammatory arthropathy
• Neck pain and radiculopathy
• Inability to provide informed consent because of a language problem, dementia or a major psychiatric disorder.