Evaluation of Non-Surgical and Arthroscopic Treatment for Hip Microinstability

Microinstability of the hip joint is an important cause of hip pain and reduced hip function in young and active individuals. Hip microinstability is due to extraphysiologic hip motion and could be secondary to acetabular dysplasia, connective tissue disorder, macrotrauma, microtrauma, iatrogenic- and idiopathic causes. Treatment for hip microinstability is initiated with non-surgical treatment consisting of physiotherapy aimed mainly at stability. If non-surgical treatment fails, surgery with arthroscopic plication of the hip joint capsule is the preferred method. This study evaluates non-surgical and arthroscopic treatment for hip microinstability regarding hip function and adverse events.

This is a prospective cohort study evaluating 26 participants above 18 years of age undergoing non-surgical and surgical treatment for microinstability of the hip joint. Participants with findings on physical examination and imaging suggestive of hip microinstability will undergo six months of physiotherapy aimed at stabilizing the hip joint. If non-surgical treatment fails, a diagnostic hip arthroscopy will be performed, and if hip microinstability is confirmed, the participants will undergo a plication of the hip joint capsule. Participants will be evaluated with Patient-Reported Outcome Scores (PROMs) and strength- and function tests at time of enrollment and at 6-, 12- and 24 months following treatment. The primary outcome is hip function determined by PROMs and strength- and function tests. Secondary outcomes include Health-Related Quality of Life (HRQL), sport activity level and adverse events.

Those participants with failed non-surgical treatment at 6 months will undergo arthroscopic treatment.

Mean Change from Baseline in Hip Function on the International Hip Outcome Tool (iHOT-12) at 24 Months

Participant-reported hip function. Minimum score 0, maximum score 100 (higher score mean a better outcome).

Mean Change from Baseline in Hip Function on the Copenhagen Hip and Groin Outcome Score (HAGOS) at 24 Months

Participant-reported hip function. Minimum score 0, maximum score 100 (higher score mean a better outcome).

Maximal hip isometric muscle force will be assessed using a dynamometer (Hoggan MicroFET2, Hoggan, Scientific L.L.C., Salt Lake City, USA) for hip flexion, adduction, abduction, and extension. The maximal developed force in Newton will be recorded. Higher Newton value means a better outcome.

Hop performance will be measured with 3 single-leg hops: vertical hop (Muscle lab, Ergotest Technology, Oslo, Norway), hop for distance and a 30-second side-hop test. Each hop test is performed with the patients holding their hands behind their back. For the vertical hop, the time from take-off to landing is converted into hop height in centimeters. In the hop for distance test, the distance between top of the toes at take-off to heel at landing is measured in centimeters. For the 30 second side hop test, one trial per leg is allowed, where the patient is instructed to hop as many times as possible over 2 lines 40 centimeters apart. The number of hops is recorded. Higher height, longer distance and higher number of hops means a better outcome.

Participant-reported health-related quality of life. Minimum score 0, maximum score 1 (higher score mean a higher health-related quality of life).

Participant-reported sport activity level. Minimum score 0, maximum score 8 (higher score mean a higher sport activity level).

Inclusion Criteria: Hip microinstability Minimum 18 years old Exclusion Criteria: Hip osteoarthritis Severe hip dysplasia Perthes disease or avascular necrosis of the femoral head Previous surgery to the hip joint

Ohlin A, Senorski EH, Sansone M, Leff G, Desai N, Lindman I, Ayeni OR, Safran MR. Protocol for a multicenter prospective cohort study evaluating arthroscopic and non-surgical treatment for microinstability of the hip joint. BMC Musculoskelet Disord. 2022 Mar 31;23(1):309. doi: 10.1186/s12891-022-05269-x.