"Total hips allow the same function as hip resurfacing."

No artificial joint makes the hip completely normal. Patients that have worn through their cartilage surface usually find an artificial joint to be an improvement. Some even say they are normal again.

A hip resurfacing mimics the natural hip joint more closely. The load is passed from the femoral component in a more natural fashion to the top of the head, rather than through the THR stem to the femoral shaft (thigh bone). Loading the thigh with a THR stem feels unnatural to most people and results in limitations.

At least 11 scientific studies demonstrate the superior function of hip resurfacing. Many studies show no difference. None show the superiority of THR. The studies that show equivalence just place the bar too low. If I place the bar only one foot off the ground, any patient can hop over, and we can erroneously conclude that there is no difference. The three best studies showing hip resurfacing superiority are as follows.

• Pritchett reported on 332 patients in which he had performed a THR on one hip and a hip resurfacing on the other. 86% preferred the resurfaced hip, and only 6% preferred the THR.
• Barrack evaluated several hundred matched young patients with THR and hip resurfacing with detailed activity questionnaires that took the bar way above standard hip questionnaires typically used in THR research. “When controlled for age, sex, and premorbid activity level, patients with hip resurfacing had a higher incidence of complete absence of any limp, lower incidence of thigh pain, lower incidence of perception of limb length discrepancy, greater ability to walk continuously for more than 60 minutes, higher percentage of patients who ran after surgery, greater distance run, and higher percentage of patients who returned to their most favored recreational activity.”
• Cobb has done numerous gait studies demonstrating that THR and hip resurfacing patients walk equally well at slow speeds, but the gait at fast walking speeds is more normal in hip resurfacing patients.

Two anecdotes that illustrate these findings are the stories of Bo Jackson who had a THR and struggled to perform as a designated hitter in baseball and has already had to revision operations for implant failure in 23 years. This is exactly what the data in young people would predict.  On the other hand, Andy Murray returned to win the European Open men’s singles tennis event 1 year after hip resurfacing and is currently ranked i# 37 in men’s tennis 4 years out from his metal-on-metal hip resurfacing.

There are two biomechanical reasons why hip resurfacing is more functional. Normal hip bearing size provides near-normal stability. Load transfer to the top of the head is more normal than loading the thigh through a THR stem. We will discuss stability later.

The THR stem is the main reason why patients struggle to perform after THR. In typical less-active patients who have THR, approximately 30% report slight or mild thigh pain. 3-5% report moderate to severe thigh pain. This is caused by load transfer from the stem. This is just with activities of daily living. When patients with THR try to return to impact sports (see Barrack above) they are unable. Many patients have pain due to the abnormal load transfer of the stem to the thigh bone (femur), with impact the sensation is naturally more pronounced and THR patients are often unable to overcome this discomfort. On the other hand, about 40% of my hip resurfacing patients choose to participate in impact sports, the only limitation is occasionally in distance runners. In some patients running more than 2-3 miles is limited, but many who have the desire are even able to run triathlons, marathons, and even ultras.

If you want to walk normally at fast speeds or if you want to run or play impact sports, you want a hip resurfacing.