The Occupational Risk Factors and Rehabilitation of Non-Arthritic Hip Pain in UK Military Personnel

Abstract

Background: The high physical demands of military occupation are associated with a high risk of musculoskeletal injuries (MSKI) impacting the force readiness and combat effectiveness of the UK armed forces (Wardle and Greeves, 2017). Intra-articular, non-arthritic hip pain (NAHP) is commonly reported among military populations with a higher reported prevalence (28%) compared with aged-matched civilians (12%) (Jochimsen et al., 2019). However, the specific occupational risk factors associated with NAHP in the UK armed forces have not been reported and there remains an unexploited potential for disease prevention. Effective and timely rehabilitation of NAHP is essential to return injured service personnel back to duty and maintain the operational effectiveness of the armed forces. Multidisciplinary team (MDT) inpatient rehabilitation is a key element of the current military best practice care pathway for NAHP. However, there is no evidence reporting the effectiveness of this approach in young, active military personnel with NAHP.

Aims and purpose: The objectives of this thesis are to: a) Describe the clinical outcomes following a three week period of MDT inpatient rehabilitation in military personnel with NAHP (study 1, chapter 3); b) Report the test-retest reliability of a new questionnaire developed to measure occupational and operational exposure to military tasks (study 2, chapter 4); c) Evaluate the cumulative, lifelong effects of occupational physical loading and the association with hip pain in military personnel (study 3, chapter 5); d) Compare the effects of inpatient MDT rehabilitation with physiotherapy led outpatient treatment on the clinical outcomes of military personnel with NAHP (study 4, chapters 6-7).

Methods: Data was collected with 385 participants across four studies. An observational cohort study examined the effects of treatment in study 1. Study 2 was a test-retest design using intraclass correlation coefficients (ICC) to evaluate the reliability and stability of 36 military task items. A population-based case-control study using logistic regression examined the relationship between lifetime physical loading and hip pain in study 3. Study 4 was a randomised controlled trial (RCT) comparing the between group differences on clinical outcomes after treatment and at three months follow-up.

Results: Inpatient rehabilitation resulted in positive changes over-time in physical function and hip range of motion (HROM), but not patient-reported outcomes or pain in study 1. The test-retest reliability of the military physical loading questionnaire (MPLQ) showed fair to almost perfect agreement (ICC range: 0.37-0.89) for all 36 operational and occupational physical task items in study 2. Driving tasks showed the strongest association with hip pain in study 3 (OR 1.4, 95% CI, 0.54 - 3.5). No association with hip pain was found for any lifting tasks. No between-group differences for any clinical outcome was found at three months follow-up in study 4. Between-group differences for muscle strength, a six-minute walk test (6MWT) and patient reported outcomes (PROs) were found immediately after the treatment intervention in favour of outpatient physiotherapy.

Conclusions: The development of injury mitigation strategies for personnel on mounted patrols should be explored. Both inpatient MDT and outpatient physiotherapy can be recommended in the management of NAHP in young active military personnel.

Date of Award	22 Feb 2023
Original language	English
Awarding Institution	University of Bath
Sponsors	Centre for Sport, Exercise and Osteoarthritis Research Versus Arthritis
Supervisor	James Bilzon (Supervisor) & Alexander Bennett (Supervisor)