Is Maximum Available Hip Extension Range of Motion of the Residual Limb Reached During Passive Prone Lying in the Acute Stage After Dysvascular Transtibial Amputation?

ABSTRACT Introduction Individuals after a transtibial amputation (TTA) are at risk to develop a hip flexion contracture, which may adversely affect future ambulation with a prosthesis. Although patients have traditionally been advised to lie prone to maintain or improve hip extension, compensatory pelvic tilting may occur in prone lying (PL). We sought to compare hip extension range of motion (ROM) in PL to the modified Thomas test (MTT) position, because research implies that, in the MTT, patients are better able to control for compensatory pelvic tilting. We hypothesized that individuals after a TTA would have a greater peak hip extension angle in the MTT position compared with the PL position. Methods Ten individuals after a dysvascular TTA, mean age of 60 ± 8.42 years, participated in this study. The same physical therapist marked the femur and pelvis for goniometric measurement of peak hip extension angle by 12 raters blinded to each other's measurements. The markers remained unchanged as six raters measured all participants in PL and six different raters measured all participants in the MTT position. Results and Discussion The intraclass correlation (ICC) indicated high interrater reliability between the raters for the PL and MTT positions (ICC = 0.985 for PL and 0.976 for MTT). The average peak hip extension angle in PL was −14.0° ± 13.3°, standard error of mean = 4.3°; and in the MTT position was −8.6° ± 15.3°, standard error of mean = 4.8° (the negative mean connotes that, on average, participants did not have hip extension to neutral for either condition). We found a mean of 5.4° ± 6.6° more hip extension ROM for the MTT position compared with PL (P = 0.028). Conclusions Our findings show that, on average, patients after a TTA have significantly greater peak hip extension angle in the MTT position compared with the PL position. Thus, passive PL may not be as effective of a stretching position for preventing a hip flexion contracture after a TTA, because PL does not always extend the patient's hip to its maximum available ROM, due to the reduced ability to control the pelvis from tilting anteriorly. Clinical Relevance Adequate hip flexor length is positively correlated with gait parameters, which include increased velocity and step length in people using a prosthesis after transtibial amputation. This study implies that the MTT position may be a better method for improving and maintaining hip flexor length over the traditional strategy of passive PL.