Relationship between plantar flexor weakness and low back region pain in people with postpolio syndrome: A case control study

Study Design: Case control study.

Objective: The purpose was to determine

if ankle plantar flexor weakness contrib- utes to low back (LB) region pain, includ- ing the lumbar or sacroiliac (SI) regions or

both, in people with postpolio syndrome (PPS).

Background: Muscle or joint pain is commonly seen in people with PPS due to years of compensating for weak muscles during gait and other functions.

Methods: Files were reviewed of 946 patients with PPS from an outpatient clinic for inclusion. Data collected included age, gender, presence or absence of LB region pain, manual muscle test (MMT) strength for the plantar flexor muscle group, and calculated total lower

extremity motor scores. One hundred fif- teen patient cases of those with LB region

pain were compared with 70 patient con- trols with no pain. A logistic regression was

performed with gender and plantar flexor grades entered as predictive variables, pain as the dependent variable. The odds ratio was calculated.

Results: Gender between the groups was significantly different at P = 0.049, as determined by a one-way analysis of variance. Plantar flexion strength was a

significant predictor, with people with plan- tar flexion weakness being twice as likely to

report LB region pain.

Conclusions: Plan- tar flexor weakness and resultant chronic

gait compensations significantly contributed

to the likelihood of LB region pain. Treat- ment of pain in these areas may be limited in

effectiveness in cases where the plantar flex- ors are weak, if interventions do not address

the primary impairments of chronic weak- ness or resultant compensations.