Osteoarthritis (OA) is a chronic joint disease with a high prevalence and a negative impact on the quality of life and a high economic burden. The most common form of OA is that involving the hands, which affects females three times more often. OA of the base of the first finger is present in 21% of the population over 40 years of age and is more frequently related to pain and disability than OA of the interphalangeal joint. In addition to pain, it can cause deformity, stiffness, reduced mobility and strength, resulting in difficulty performing common activities such as opening vessels, carrying weights and writing.

OA of the base of the first toe is mainly treated with conservative modalities, while surgical treatment will be reserved for those whose debilitating symptoms persist despite adequate conservative management. Surgical management, however, is associated with a number of complications, including tendon rupture, sensory changes, and wound infection.

Although a number of conservative therapies have proven effective for the management of hand OA, there are few high-quality clinical studies in the literature to date.

The review of the literature has shown that in thumb carpometacarpal osteoarthritis the use of braces leads to a reduction in pain, particularly in the long term, based on data from two studies. Additionally, hand exercises could improve grip strength and hand function.

Regarding pharmacological management, insufficient data are available to support the effectiveness of intra-articular therapy with corticosteroids or hyaluronic acid and their use is not recommended by the American College of Rheumatology guidelines (ACR) of 2012 . On the other hand, nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended to relieve pain associated with first toe base OA, and topical formulations are recommended over oral NSAIDs in more recent guidelines, due to a profile of superior security. However, their effect on function is minimal and transient (no more effective than placebo after 2 weeks).

The combination of non-pharmacological and pharmacological modalities in the management of hand OA is recommended by the European League Against Rheumatism (EULAR) guidelines and is frequently used in clinical practice. Despite this, direct evidence of the effectiveness of this strategy is lacking. There have been some studies evaluating combined treatment, although they have generally not been specific to OA of the base of the first toe. Furthermore, the combinations studied usually included exclusively nonpharmacological modalities, and to date no strategy has been found to be highly effective for improving pain and function for first toe base OA.

Determining an evidence-based treatment approach with a clinically significant effect on clinical outcomes would provide healthcare providers with a basis for decision making for the treatment of patients with thumb carpometacarpal osteoarthritis. This strategy does not yet exist, and decisions about the best combination of interventions are generally based on personal experience and the personal opinion of healthcare professionals.

Inclusion Criteria:

• arthrosis of the trapezoid-metacarpal with stage 1 or 2 of the Eaton-Littler radiographic classification and pain (recent radiograph within 6 months previously);
• clinical picture that has been occurring for at least 6 months;
• pain scored with VAS scale at least 4/10.

Exclusion Criteria:

• rheumatoid arthritis or outcomes of trauma in the affected area,
• contra-indications to treatment with shock waves (neoplasia, pregnancy, thrombocytopenia, epilepsy, uncompensated heart disease or arrhythmia, pacemaker, local infections),
• corticosteroid infiltration or physical therapy in the previous 4 weeks.