The Role of Extra Corporeal Shockwave in Treatment of Trigger Finger
Authors: Ahmed Rana A , Arfa Mona M , Ahmed Sahar F , EL- Gharbawy Nermin H 
Published: August 2023

Background
Trigger finger, or stenosing tenosynovitis, is a condition where the normal smooth gliding of the flexor tendons through the fibrous tendon sheath of the digit is altered. Inflammation where the flexor tendon enters the sheath leads to either thickening of the fibrous pulley and/or inflammation or nodular enlargement of the tendon. This enlargement of the tendon results in locking and clicking symptoms of the affected finger, Treatments for trigger finger in order of invasiveness include splinting, NSAIDs, physical therapy, corticosteroid injections, and surgical release of the tendon sheath. Ultrasound allows for noninvasive visualization of the soft tissues, and also provides good depiction of annular pulleys and flexor tendons; the extracorporeal shock waves are defined as sound waves that can maximize the pressure of the target tissue over a few nanoseconds.Recently, extracorporeal shock wave therapy (ESWT) has been proposed as an alternative treatment in patients not responding to conservative treatments. Currently, extracorporal shock wave therapy (ESWT) has been widely used in tendinopathies, including trigger fingers with high success rate, while the complications are low and can be neglected.

Objective
To evaluate the efficiency of shockwave therapy in the treatment of trigger finger.

Patients and Methods
This prospective single-center study was carried out on 15 patients (aged 53.133± 9.039 years, 66.67% females and 33.33% males) complaining of symptomatic trigger finger. 6 sessions of ESW therapy were given to all patients with one week interval. Before and after treatment with ESWT sessions, scoring was done to all patients using Numerical Pain Rating Scale (NPRS), Quick Disability of Arm, Shoulder and hand score (Quick DASH), Range of motion assessment of fingers: Active and passive. MSUS was done for all patients before starting the sessions for accurate diagnosis and was repeated one month after patients had finished 6 sessions of ESWT as an assessment tool.

Results
Our patients showed a high statistical significant difference after one month follow up regarding the numeric pain rating score (NPRS), the Quick DASH score, range of motion (Active Flexion MCP of affected finger), Green`s classification, locking and snapping, thickness of A1 pulley & synovial thickness.
Before ESWT sessions, we found that duration of pain was correlated positively with thickness of A1 pulley and negatively with ROM “Active Flexion MCP”. Also ROM “Active Flexion MCP” correlated negatively with thickness of A1 Pulley. Thicknesses of synovial membrane was positively correlated with NPRS and Quick DASH score.
After ESWT sessions, ROM “Active Flexion MCP” was correlated negatively with and thickness of A1 pulley. Thicknesses of synovial membrane was positively correlated with NPRS, Quick DASH score and thickness of A1 pulley, But it was negatively correlated with ROM “Active Flexion MCP”.

Conclusion
We concluded that ESWT is an effective method for treatment of trigger finger and is non invasive compared with surgical treatment. It improves pain, finger ROM and thickness of synovial membrane. We also concluded musculoskeletal ultrasonography is helpful for objectively understanding the severity of trigger finger and its response to treatment, by examining the thickness of the flexor tendon and A1 pulley.