Short-Term Effects of Trigger Point Dry Needling on Pain and Disability in Subjects with Patellofemoral Pain Syndrome

Patellofemoral pain syndrome (PFPS) is a prevalent condition that primarily affects active young people and represents a clinical puzzle due to its recurrent nature, with 70-90% of patients presenting with chronic symptoms. Trigger point dry needling has emerged as a promising therapeutic intervention for various musculoskeletal conditions, but its effects on PFPS had never been investigated scientifically. This randomized clinical trial was the first to specifically examine the efficacy of dry needling in patients with PFPS, comparing it with a sham treatment. The study included 60 military beneficiaries with a clinical diagnosis of PFPS, 36 of them men, aged 18-40 years.

Participants were randomized into two groups: real or sham dry needling. The treatment protocol focused on the quadriceps femoris muscles (vastus medialis, rectus femoris, and vastus lateralis), based on Travell and Simons' theory that trigger points in these muscles can generate the peripatellar pain characteristic of PFPS. The treatment consisted of inserting acupuncture needles into six trigger points identified by palpation, using 'sparrow pecking' and 'cone' techniques to elicit local twitch responses. The control group received sham treatment with a sharp object and guide tube without skin penetration, maintaining participant blinding through a curtain positioned at the waist.

Assessments included validated pain scales (numeric pain rating scale), function (Lower Extremity Functional Scale and Kujala Anterior Knee Pain Scale), and global perception of change, collected before treatment, immediately after, and at 72 hours. The results showed that both groups experienced clinically significant pain reductions (30% improvement), but there were no statistically significant differences between groups at any time point (p=0.22 immediately and p=0.31 at 72 hours). Similarly, no significant differences were observed in function and disability measures. Blinding was partially effective, with 63% of the sham group and 71% of the real group correctly identifying their treatment.

The clinical implications suggest that a single isolated session of dry needling is not superior to placebo effect for PFPS in the short term. The authors acknowledge several important limitations: follow-up of only 72 hours (inadequate for a chronic condition), single treatment session (different from usual clinical practice), focus limited only to the quadriceps (ignoring proximal hip and trunk muscles), and use as an isolated intervention (contrary to evidence favoring multimodal approaches). The study contributes significantly to the literature by being the first to investigate dry needling in PFPS with rigorous methodology, establishing a baseline for future research. Recommendations for future studies include multiple treatment sessions, longer follow-up periods, inclusion of hip and trunk muscles, and combination with other interventions such as strengthening, stretching, and manual therapy.

The identification of subgroups of patients who respond better to dry needling also represents a priority area of investigation, following a successful model in other conditions such as low back pain.