By Andrew Wolfanger, PT, DPT
Total Hip Arthroplasty (THA) is a highly effective surgical procedure for those suffering from significant pain and disability due to end stage osteoarthritis. The procedure has been shown to consistently reduce pain, restore function, and improve patient reported quality of life.
Surgeons utilizing a posterolateral surgical approach have long utilized hip precautions as a means to minimize dislocations after surgery. These precautions generally include limiting hip flexion, adduction, and internal rotation. Patients who have undergone this surgery are taught to avoid lifting their knee past 90 degrees, from twisting their leg inwards, and from crossing their legs. Additional precautions include sleeping in the supine position with a pillow between knees and also avoiding low seats. The precautions are often kept in place from anywhere between 6 to 12 weeks.
Although long theorized to reduce early dislocations, there is new research that suggests hip precautions may no longer be necessary. In a recent retrospective study performed at HSS, researchers compared dislocation rates in patients who were placed on standard hip precautions with those that were placed on a pose avoidance protocol. Those on a pose avoidance protocol were advised to simply avoid a single pose that included flexion and external rotation (similar to how one would cross over their leg to put on a shoe or shave their leg). The results demonstrated no significant difference between the 2 groups with regards to dislocation rates. The dislocation rate in the standard hip precaution group was .53% while the dislocation rate in the pose avoidant group was .46%. Dr. Sculco, the lead author of this study, concluded that hip precautions are unnecessary for the majority of patients. He cautioned that patients should follow an individualized program, and there are those that may benefit from a more conservative approach.
A randomized controlled study performed at the WVU School of Medicine also found no evidence that standard hip precautions after THA influenced dislocation rates. In this study, 159 patients were randomized to a standard hip precaution group while 154 patients were randomized to a group with no precautions. There was no statistical difference found between the groups as there were 2 recorded dislocations in the standard hip precaution group (1.3%) and only 1 dislocation in the group without precautions (0.7%). All 3 dislocations occurred due to falls.
Ultimately, there is limited evidence to support the implementation of hip precautions after a THA. In both studies, dislocations after a THA only occurred in a very small percentage of patients, and hip precautions had no influence on the rate of dislocation. It is theorized that limiting hip precautions may also expedite recovery as it will limit fear associated with violating restricted movements. More research regarding recovery rate and patient reported outcomes is needed to validate this theory. As seen with the 2nd reference study, hip dislocations often happen due to falls. While undergoing post-operative rehabilitation it is paramount for physical therapists to incorporate static/dynamic balance activities and to also teach fall prevention strategies. Despite the new research regarding hip precautions, it is important to continue to follow your surgeon’s and PT/OT’s individualized approach to ensure safe and maximal recovery.