Hip resurfacing arthroplasty (HRA) is an operation that is used to treat severe hip arthritis and is offered by me as an alternative to the standard operation of stemmed total hip replacement (THR).
Most surgeons in the world will recommend a standard stemmed THR to treat your condition. Although this is an excellent operation and is generally quite successful, I believe that I can do better job for you with an HRA. If you would prefer a standard stemmed THR, I would tell you that your chances of an excellent outcome are better with an HRA, but the choice is yours to make. I would do either operation for you. I have published excellent long-term outcomes with both operations that substantially outperform industry benchmarks (Registry data).
The material risks of HRA are spelled out in great detail in both the consent form as well as on my website that I have encouraged you to review.
No one is able to make your hip completely normal. But I am likely to get much closer to this goal if I perform a HRA rather than a THR. Outright failures leading to revision (changing out implants) surgery occur in approximately 1% of cases before 1 year and less than 3% at 18 years. Reoperations (corrective operations where the implants are not removed) are required in less than 1%. Other complications not requiring another operation occur in another 2%. This is the highest published success rate for any type of hip surgery in North America.
Immediately after surgery your original hip pain caused by missing cartilage is gone. This is because I have prepared the bone and fixed an implant into the bone on both sides of the joint. Painful bone rubbing on bone has been converted to painless implant rubbing on implant. Postoperative pain is mainly a result of the controlled surgical trauma required to get access to your hip. Initially surgical pain is much worse than your original arthritic pain. This is why we use a multimodal pain management system including some narcotics to keep you reasonably comfortable. However, many (not all) people can qualitatively tell the difference between their old arthritic pain and the new muscle pain. It may feel much like a severe bruise. The soft tissue pain rapidly subsides within a few days. Most people stop using narcotics after 3-4 days and discontinue Tylenol, meloxicam and ice after 2 weeks.
Patients are usually able to resume walking and dispense with walking aids within a few weeks. But we need to limit activity to some extend for 6 months to allow adequate healing. People with very low bone density or a BMI>30 are at higher fracture risk and are advised to stay on crutches for 6 weeks to mitigate this risk.
The implant needs to achieve bone ingrowth, the ligaments and muscle need to heal and the bone is fragile for about 6 months. Excessive activity is damaging to the healing process The most common early failure mode is femoral neck fracture. This requires revision to a stemmed THR. These always occur in the first 6 months. The overall incidence is 0.2% (1/500). Patients who have low bone density and those with a BMI of over 29 are at higher risk. To mitigate risk in these groups, we prescribe bone strengthening medication and a slow (10 -week) restricted weight bearing protocol. With these measures the risk in these high-risk groups is similar to the other patients. These fractures are typically stress fractures that happen spontaneously or from minor falls that don’t normally result in a serious injury.
Most operations are performed as outpatient procedures in the ambulatory surgery center (ASC) that is owned by my group. The approach is posterior. The typical surgical time is 1.5 hours, the mean blood loss is 200 ml and you will not require a transfusion . After surgery you walk around the center and climb stairs with the nurse or therapist. You are given all your required medication. We give your caregiver detailed instructions and a written 6 page handout that records these for you in great detail. When you are eating, drinking urinating and walking with assistance you are released. Usually in under 3 hours after coming out of surgery. Your pain will be well-controlled with a multimodal pain management protocol. You will be given contact phone numbers to reach us anytime you need us.
In the typical recovery patients are able to
- drive in 3-4 days as soon as they are off narcotics (using the left foot on the brake for right -sided surgery).
- return to a desk job within 1-2 weeks.
- resume upper extremity workouts without loading the legs in 2 weeks.
- use crutches ( weight as tolerated ) for 1-2 weeks, and a cane in the opposite hand for 1-2 weeks.
- Progress to walking to one mile by 6 weeks. This should be viewed as maximum ceiling to minimize fracture risk. My motto is “less is more” during the first 6 weeks.
- Initially stairs are ascended one foot at a time, at 6 weeks you can start foot over foot stair climbing with assistance of a rail.
There is reason to believe that fracture risk may be further reduced below 0.2% by just remaining on crutches for the full 6 weeks. You can choose this depending on your risk tolerance. On the other hand, if you do more than I recommend, you are increasing your fracture risk.
For typical patients, at 6 weeks I approve of gradually increasing walking distances beyond 1 mile, gently using an exercise bike or elliptical, swimming, gradually returning to golf, gently starting some lower extremity resistance and weight training up to 50 pounds.
Recommended restrictions up to 6 months are:
- Impact activities such as running and jumping
- Stairclimbing exercises
- Lifting more than 50 pounds.
- Extreme bending such as squats or yoga.
- Fall risk activities such as ladder climbing or biking outside.
At 6 months the fracture risk has essentially resolved, the implant is well ingrown and the ligaments are healed. You are released to unrestricted activity including heavy labor, impact sports and high range of motion activities such as yoga.
The most extreme activities such as unprotected rock climbing, slide tackling in soccer, jumping out of airplanes, sport fighting, and ski jumping should be avoided until 1 year.
Most patients feel better than before surgery at 6 weeks, but some take as long as one year to turn the corner. For most people I would estimate healing to be 90% complete at 6 months, 98% complete at 1 year and 100% at 2 years. Over half of patients after 2 years say their hip feels completely normal. The other half say it is near normal with some minor residual issues. About 2 percent say they have moderate or severe residual pain; 1 percent are not satisfied. For comparison, the rate of residual moderate or greater unexplained pain or dissatisfaction in total knee replacement is 30% and in stemmed total hip replacement is 20%. In patients who are dissatisfied with a THR or HRA done elsewhere, I will only offer revision surgery if I can reasonably determine a cause of failure, I do not perform exploratory revisions for unexplained pain because it carries a less than 50% success rate. On the other hand, if one of my patients has residual unexplained pain after 1 year, I would reluctantly agree to perform a revision to a THR, but I would recommend against it because of the low success rate. Unexplained pain means significant residual pain after surgery for which no obvious cause can be found on detailed testing: X-rays, ions, other bloodwork, MRI and bone scan.
Running is possible for all HRA patients (unless they have another problem that limits it). Almost all patients can run a few miles. Distance running, however, is not always tolerated. It is, however encouraged. Running does not increase your implant failure rate. The cause of distance running tolerance is not understood. I would simply say that I never make anyone a normal hip. For some people a hip resurfacing is not good enough to tolerate this extreme activity. In those that don’t initially tolerate running at 6 months, persistently running multiple times a week up to the point of soreness but not pain can lead to improvement. Running or other extreme impact sports do not seem to affect the failure rate of HRA, they are generally poorly tolerated in patients with stemmed THR and do increase the failure rate of these implants.
My published cumulative failure rate is approximately 2% by 18 years in a very large cohort of over 6000 cases. This is superior to any THR report from Europe or North America. Failure means that a revision has been performed, usually for an identified cause such as fracture or implant loosening. All causes of failure, reoperation and other complications are listed in the latest results section on my website.
The advantages of hip resurfacing over THR are:
- Better functional outcome especially with Impact sports, but also with rapid walking. (The THR stem can bother people even at low activity levels).
- Preference: 85% of patients who have one of each prefer the resurfacing.
- Fewer dislocations ( Because the ball size is normal in HRA)
- Bone preservation
- Lower short term (0.2 %vs 1-2% by 6 months) and lower long term ( 1% vs 7% by 20 years) fracture rate than for THR.
- Less problems with wear or corrosion. (No wear failures in over 4000 cases since 2009 in my HRA, compared to 1-3 % trunnion corrosion failures with THR)
- Lower 10 year all-cause mortality (20% - 600% in 6 publications)
Disadvantages:
- Technically more demanding to perform with a long learning curve
- Duration of surgery is longer especially for the inexperienced surgeon, increasing the work done for the same CPT code 21730 as stemmed THR.
- Patients with unexplained pain with HRA get unhelpful revisions from THR surgeons. Patients with unexplained pain after THR are not operated on and are left alone.
