Hip dysfunction-related urinary incontinence: a prospective analysis of 189 female patients undergoing total hip arthroplasty. Tamaki T, Oinuma K, Shiratsuchi H, et al. International J Urol. 2014; DOI: 10.1111/iju.2014.

MJ Strauhal, PT, DPT, BCB-PMD

July 9, 2014 Pelvic PT Distance Journal Club

Purpose of the study:  to evaluate the symptoms of urinary incontinence (UI) before and after total hip arthroplasty (THA)

·         Study was done at the Funabashi Orthopedic Hospital, Japan

Background:

·         Osteoarthritis (OA) of the hip is an important cause of pain and disability

·         In Japan, prevalence of secondary OA from congenital dislocation or acetabular dysplasia is high among elderly women

·         THA is one of the most frequent surgeries carried out to improve QOL related to OA

·         In daily practice, patients report improvement in UI post THA

Subjects:

·         189 females (mean age 62.3 years) with hip OA who had undergone THA from October 2010 to August 2011

o   81 of 189 subjects reported UI pre-op THA (mean age 64.0 + 9.9 years)

§  55 (? 53) of these 81 (65%) reported primarily stress UI (UI with cough/ sneeze)

§  43 (53%) of these 81 reported urge UI (before getting to the toilet); Table 2

o   108 of 189 subjects did not report UI pre-op THA (mean age 61.1 + 11.2 years)

o   No significant intergroup difference in mean age (p = 0.063)

·         Simultaneous bilateral THA was carried out in 30 of these women

·         All THA were muscle-sparing direct anterior approach (AA) THA

Methods:

·         Questionnaire-based prospective study evaluating the symptoms of UI pre and post THA

o   International Consultation on Incontinence Questionnaire- Short Form (ICIQ-SF) was completed by patients before surgery and at 3 months post THA

o   UI was defined as >1 for the ICIQ-SF question: “How often do you leak urine?”

§  See stats re: UI above

o   A decrease in ICIQ-SF of > 1  point = improvement post-op

o   An increase of > 1 point = worsening post-op

·         Hip function was evaluated pre-op using the Japanese Orthopaedic Association (JOA) hip score

o   JOA hip score has been validated as an assessment tool for Japanese women with OA of the hip (Kuribayashi, et al. J Orthop Sci. 2010; 15:452-458.)

o   Separate scores for pain (40 points), range of movement (20 points), gait (20 points), ADL’s (20 points) = maximum score of 100

o   No significant intergroup difference in JOA scores between the UI and continent groups (p = 0.431)

§  JOA score in UI group 45.2 + 10.6

§  JOA score in continent group 45.9 +  11.8

·         Statistics

o   The Student’s paired or unpaired t-test

o   P < 0.05

Results:

·         No orthopedic complications were reports

·         Both groups received rehab starting on day 1 post-op including AROM, PROM, ambulation FWB

·         In the UI group (81 of 189) post-op THA

o   UI ameliorated in 52 of 81 (64%)

o   UI remained unchanged in 26 of 81 (32%)

o   UI worsened in 3 (4%)

o   Mean total ICIQ-SF score in patients who had UI pre-op improved from 6.0 to 3.5 (p = 0.000244); Table 1

·         In the continent group (108 of 189) post-op THA

o   UI remained unapparent in 105 (97%

o   UI became apparent (worsened) in 3 (3%)

Discussion:

·         81 of 189 (43%) Japanese women undergoing THA report UI

·         Some of these women may have suffered functional incontinence due to hip dysfunction, but  SUI seemed to be the most common form

·         ICIQ-SF improved in 64% of patients suggesting a relationship between hip function and pelvic floor function

o   UI may be a result of hip dysfunction

o   “Loose” PFM are strongly associated with SUI

o   LA (PFM)originates from obturator internus (OI) fascia

o   Muscles around the hip atrophy with OA

§  Fig. 1  MRI of a 28 yo woman w/o hip symptoms showing close relationship between OI and LA

§  Fig.2 CT image of a 66 yo woman with left hip OA showing significant left OI atrophy

o   Post THA hip muscles can be “tensioned” as a result of muscle strengthening and improved hip ROM and the authors hypothesized that this would improve a “loose”  pelvic floor

o   General health-related QOL can be improved post THA

§  Walking

§  Pain

§  UI

·         UI became more severe in 4% of the UI group and became apparent in 3% of the continent group

Limitations:

·         No control group

·         Follow up period was 3 months- unclear when UI diminished/ improved

·         No OB or GYN history analyzed

·         No urological exam included

Journal Club Discussion:

·         What are your thoughts regarding clinical application of the results of this study?

·         Do you consider the methodology used for this study to be robust?  Why or why not?

·         What other limitations do you see with this study?

·         What other questions/ hypotheses would you have liked to see the authors explore?  Why