Arthroscopic Treatment of Patients in Horsens and Aarhus With FemoroAcetabular Impingement: the HAFAI-cohort
Condition: Femoracetabular Impingement
MeSH terms: Femoracetabular Impingement
Study type: Observational

Summary: 
      Purpose: The aim of this prospective cohort is to evaluate patients before, 6 and 12 months
      after arthroscopic surgery for FAI and compare the results to people without hip problems.

      Methods/design: Sixty patients with FAI and 30 persons without hip problems will be included.
      Pre- and postoperatively, patients will be evaluated by CT-scans. All participants will have
      their hip flexor and extensor muscle strength assessed and have performed kinetic and
      kinematic analyses of daily activities with 3D motion capture. Further, self-reported
      questionnaires on hip related pain, quality of life and sports activities will be collected.
      Finally, participants will have their daily physical activity monitored with tri-axial
      accelerometers for five consecutive days.

      Perspectives: With this prospective cohort study the outcome of arthroscopic treatment of FAI
      within one year after surgery will be evaluated. If the patients fail to reach reference
      values one year after surgery, altered surgical procedures or rehabilitation programs to
      optimize treatment for the patients may be explored in future studies. Further, the
      investigators expect to perform long-term follow up to evaluate reoperations, conversions to
      total hip arthroplasty and development of osteoarthritis for the patients surgically treated
      for FAI.
    

Detailed description: 
      Introduction Femoral acetabular impingement (FAI) is caused by an abnormality in the
      acetabular shape or orientation (Pincer-type) by a shape abnormality in the proximal femur
      (Cam-type) or by a mix of the two conditions. FAI causes repeated minor damage to the labrum
      and edge of the acetabulum. The damage to the joint is proposed to lead to early
      osteoarthritis (OA) of the hip, but whether FAI is a cause or result of OA is discussed.
      Surgery can reduce symptoms caused by Cam or Pincer impingement and may prevent future damage
      to the hip joint. However, different surgical techniques are used, and only few long-term
      studies of the surgery exist. The latest reviews conclude that 1) the effectiveness of the
      surgery is not clear, 2) it is not clear how surgery affects functional performance for the
      patients and 3) it is unknown how surgery for FAI affects the patients in a long-term
      perspective.

      Material and methods

      Patients:

      Inclusion criteria

        -  Planned hip arthroscopic treatment at Horsens Regional Hospital by Consultant Bent Lund

        -  A diagnosis of CAM and/or pincer impingement

        -  For patients with Cam, an alpha angle > 55 degrees on an anterior/posterior (AP)
           standing radiograph

        -  For patients with Pincer a center edge angle > 25 degrees on an AP radiograph

        -  No signs of retroversion in the lower 2/3 of the hip joint on an AP radiograph

        -  No posterior wall sign on an AP radiograph

        -  Osteoarthritis grade 0-1 according to Tönnis' classification

        -  Lateral Joint space width of > 3 mm

        -  Age between 18 and 50 years

      Exclusion criteria

        -  Previous hip operations of the included hip

        -  Persons with FAI secondary to other hip conditions such as Calvé Perthes and
           epiphysiolysis.

        -  Alloplastic surgery at the hip, knee or ankle region (both legs)

        -  Neurological diseases

        -  Cancer

        -  Inability to speak or understand Danish

        -  Pregnancy at the time of inclusion

      Control persons (healthy volunteers) Thirty gender and age-matched persons with no known hip,
      knee or ankle region problems will be included as controls.

      Primary outcome measures

        -  Hip and pelvis kinetics and kinematics during walking, stair climbing, stepping,
           sit-to-stand and drop jump

        -  Hip extensor and flexor maximal muscle strength during isometric and isokinetic
           contractions

        -  Hip extensor and flexor rate of force development during isometric contraction

        -  Objectively measured daily physical activities during 5 days

        -  Hip- related self-reported health measured with the Copenhagen Hip and Groin Outcome
           Score

      Secondary outcome measures

        -  Knee and trunk kinetics and kinematics during walking, stair climbing, stepping,
           sit-to-stand and jump

        -  Hip extensor and flexor rate of force development during isometric contraction

        -  Self-selected walking speed

        -  Presence of intra-articular pathology examined with FABER and impingement tests

        -  Visual analog scale, pain

        -  Patient expectations

        -  Reasons for choosing surgery

        -  Patient global treatment outcome

        -  Patient-acceptable symptom state

        -  EQ5D-Visual analog scale

        -  Failure

        -  Re-operations and injections during the first year after surgery

        -  Self-reported present sports activities

        -  Time spend at preferred sports activity present

        -  Time spend at sports activities during childhood

        -  Sports activities during childhood

        -  Return to sports activities

        -  Education

        -  Employment

        -  Smoking habits

        -  Alcohol intake

        -  Intake of analgesia

        -  Comorbidities

      Other Pre-specified Outcome Measures:

        -  Alpha angle

        -  Wiberg's center-edge (CE) angle

        -  Tönnis' acetabular index (AI)

        -  Retroversion of acetabulum

        -  The position of the femoral head in relation to the neck

        -  Osteoarthritis grade according to Tönnis' classification

        -  Lateral hip joint space width

        -  Information about the surgical procedure immediately

        -  Deviation from rehabilitation program

        -  Duration of pain

        -  Body Mass Index

        -  Body fat percentage

        -  Age

      Procedure

      Patients scheduled for hip arthroscopic treatment at Horsens Regional Hospital will receive
      written and verbal information about the study and after informed consent included
      consecutively. After agreeing to participate, the patients will have a pre-operative CT-scan
      of the included hip. At Aarhus University, patients will have a clinical examination session
      including measurement of height, weight and fat percentage. They will have their hip extensor
      and flexor muscle strength assessed in an isokinetic dynamometer and perform walking, stair
      climbing, stepping, sit to stand and a drop jump with 3D-motion capture. Patients will
      complete the HAGOS-questionnaire together with the other pre specified self-reported measures
      described.

      After all tests are completed, the patients will be instructed in wearing a 3-axial
      accelerometer for five days, attached to the thigh of the non-affected leg to monitor daily
      physical activity.

      At a three, six and nine month follow-up patients will complete HAGOS, pain scores and
      self-reported measures of return to sport, work, re-operations and injections after surgery
      and EQ5D-Visual analog scale.

      At a one year follow up, preoperative measures will be repeated. Further, at six month and
      one year follow up the patients will report fulfillment of expectations, patient global
      treatment outcome and patient willingness to repeat surgery.

      All controls will meet at Aarhus University for a single assessment of the same measures as
      the patients except from CT-scans and outcome measures related to the surgery.

      Statistics

      Patients and controls will be compared with multiple regression analysis adjusted for age,
      gender and body weight if the assumptions for the model is met. If not, they will be compared
      using un-paired non-parametric statistics.

      The longitudinal measures of the patients pre, three, six, nine month and one year after
      surgery will be evaluated in a paired set-up.

      Further analyses

      Based upon the preoperative CT-scan, the patients will be split into subgroups: FAI will be
      classified as Cam (alpha angle > 55˚), Pincer (center edge angle > 25˚ from CT and AP
      radiograph and/or crossing sign and ishial spine sign) and Mixed when there is a combination
      of Cam and Pincer. We will investigate how these subgroups affects outcome measures. Further,
      we will investigate how demographics, preoperative and postoperative muscle strength and pain
      affects the results of the surgery and rehabilitation procedure.

      Sample size

      The primary end point for the study is one year after surgery. For the muscle strength
      assessment, sample size is based upon pre- and post-operative values from Casartelli et al.
      (2) with a level of significance of 0.05 and a power of 90 %, the patient group should
      consist at least 53 persons. Taking possible drop-outs in account our goal is to include 60
      patients. We will include 30 controls persons for comparisons.

      Ethics

      The Danish Biomedical Research Ethics Committee, Central Denmark Region (1-10-72-239-14) and
      the Danish Data Protection Agency have approved the project (1-16-02-499-14).

      Economy and dissemination

      Financial support will be applied for at internally at our institution and externally at
      various foundations. Both positive, negative and inconclusive results will be published in
      international journals and presented at conferences.

      References

        1. Mannion AF, Impellizzeri FM, Naal FD, Leunig M: Fulfilment of patient-rated expectations
           predicts the outcome of surgery for femoroacetabular impingement. Osteoarthritis and
           Cartilage 2013, 21:44-50.

        2. Casartelli NC, Maffiuletti NA, Item-Glatthorn JF, Impellizzeri FM, Leunig M: Hip muscle
           strength recovery after hip arthroscopy in a series of patients with symptomatic
           femoroacetabular impingement. Hip international : the journal of clinical and
           experimental research on hip pathology and therapy 2014:0.

        3. Paulsen A, Roos EM, Pedersen AB, Overgaard S. Minimal clinically important improvement
           (MCII) and patient-acceptable symptom state (PASS) in total hip arthroplasty (THA)
           patients 1 year postoperatively. Acta orthopaedica. 2014;85(1):39-48.
    

Intervention name(s): Arthroscopic surgery of the hip joint
Intervention type(s): Procedure
Intervention description(s): Arthroscopic treatment of Femoroacetabular Impingement
Other intervention name(s): Hip Arthroscopy; Arthroscopic surgery of Femoro-Acetabular Impingement
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients with Femoro Acetabular Impingement and Healthy volunteers