Are baseline factors associated with persistent pain in people with Femoral Acetabular Impingement Syndrome after a physiotherapy-led rehabilitation programme?

Background Femoral acetabular impingement syndrome (FAIS) causes hip pain in adults.

Pain is caused by contact of the femoral head with the acetabulum in activities such as squatting, due to bone formation called a cam; a morphological variation at the femoral head/neck junction.

Repeated contact of the cam with the acetabulum leads to Osteoarthritis thus the mechanistic cause of pain is believed to be nociceptive (tissue damage), although cam morphology can exist asymptomatically.

Physiotherapy-led rehabilitation (PLR) involves strengthening the muscles around the hip, changing the movement pattern of the hip joint, averting impingement (and its associated nociceptive pain driver) although some patients remain symptomatic. One study showed only 32% of patients with FAIS improved following a PLR program.

My PCAF identified neuropathic pain, measured by a validated instrument (PainDETECT) in a subgroup of patients with FAIS and was associated with elevated levels of anxiety and depression and poorer outcome, questioning the mechanistic cause of pain. The presence of these characteristics challenges the nociceptive pain construct supporting PLR.

Research question: Are baseline factors associated with persistent pain in people with Femoral Acetabular Impingement Syndrome after a physiotherapy-led rehabilitation programme? Aims and objectives.

To conduct an observational longitudinal study identifying patient characteristics and pain phenotypes associated with persistent pain despite PLR. This study will achieve its aim through the following objectives: 1).

Identify patient characteristics associated with poor outcomes defined by ongoing pain and/or reduced hip range of movement for the treatment of FAIS. 2).

Characterise pain phenotypes, emotions, and beliefs in patients with FAIS to determine the nature and spread of pain using validated pain questionnaires awaiting PLR. 3).

Combine the physical characteristics from objective 1 and pain phenotypes and beliefs from objective 2 to identify an association with poor outcomes after the completion of a PLR program.

Methods Objective 1 A systematic review to identify the known bio-psychosocial influences on patient outcomes after treatment for FAIS.

Objective 2 A cross sectional study following preparatory work from my PCAF using validated questionnaires exploring pain phenotypes, quality of Life (QoL) and emotional elements and patient demographics in patients with FAIS awaiting PLR.

We will invite 175 participants from four orthopaedic hospitals identified from waiting list databases and patients attending orthopaedic clinics from 4 hospitals sites. The questionnaires are: PainDETECT. Fibromyalgia survey questionnaire. Tampa scale of Kinesiophobia (TSK-11). Hospital Anxiety and Depression scale (HADS).

Pain Catastrophising Scale (PCS) International Hip Outcome Tool (iHOT33). SF36.

Objective 3 Multicentred Observational Longitudinal study: To identify which patient characteristics, and pain phenotypes associate with persistent pain and poor hip function post PLR. Participants from objective 2 will be followed-up after 6 sessions of a PLR. Repeat questionnaires will be completed and then compared with baseline measurements.

Timelines for delivery See GANTT Chart (fig 1) Anticipated Impact: The findings from this research will provide: Improved selection of appropriate physiotherapy treatment Guidance on tailored treatment e.g., bio-psychosocial /psychologically informed versus mechanical strength & conditioning approach.

Improved physiotherapy outcomes Improved health economics Dissemination: Physiotherapists, and patients. Orthopaedic/physiotherapy conferences/peer review papers.