Introduction
Total hip replacement (THR) has dramatically changed the way degenerative hip diseases are treated and is considered to be one of the most successful orthopaedic interventions of its time. Since the first attempted THR in 1891, tremendous advances have been made in surgical technique, implant materials manufacturing and design as well as related technologies. These advancements allow for a reproducible technique that provides significant pain relief, a stable hip joint with improved range of motion, and an ever increasing life span of the joint replacement. Here we summarize some of the advances made in recent years in the specialty of THR that we feel have been most noteworthy.

Preoperative Assessment
Several studies have highlighted the importance of a complete and thorough preoperative medical assessment. As joint replacement is an elective procedure with significant risks, it is critical that our patients’ health be optimized before proceeding with surgery. All joint replacement candidates are required to see their primary care provider for an evaluation of their general health with management and stabilization of any existing medical problems prior to scheduling surgery.
Certain medical conditions are known to place a patient undergoing joint replacement at higher risk of complications (i.e. blood clot, cardiopulmonary event, infection etc.) after surgery. Patients with established cardiopulmonary problems are required to see their cardiologist prior to surgery for risk stratification and problem management. Patients with diabetes are at higher risk for infection and must have their blood sugar under excellent control in order to proceed with THR. We require a documented hemoglobin A1C of 7 or less before scheduling surgery.
We screen all patients for Methicillin Resistant Staphylococcus Aureus (MRSA) colonization. Those individuals who test positive for MRSA receive directed antibiotic treatment prior to surgery and are given supplemental antibiotics during and after surgery to prevent joint infection. Poor nutrition also places a joint replacement patient at high risk for infection and wound complications. All patients undergo a blood test to identify those with low protein and vitamin D levels which are markers of malnutrition. If found to be low, those patients should improve or supplement their diet prior to surgery.
Obesity has also been directly linked to poorer outcomes after THR, in particular infection and wound complications. For this reason, our patients are asked to lower their body mass index (BMI) below 40 before surgery is scheduled. Additionally, smoking tobacco (and like products) has several well established side-effects, of which, diminished healing capacity and reduced immune system function are of particular concern for those patients considering THR. We ask that our patients be smoke-free at the very least several weeks before and after surgery.
Patients who are depressed or anxious tend to do less well and these conditions should be controlled before surgery. Patients who are on chronic narcotic medication prior to surgery have a difficult time with pain control and have a higher complication rate longer hospital length of stay than patients who are not on narcotics. We therefore ask that patients be off narcotics 6 weeks before surgery.
A BMI under 40, Hgb A1C less than 7, no narcotic use and abstinence from smoking are strict requirements for those considering total joint replacement.

Surgical Approach
The hip joint can be approached in several ways and therefore many different exposures have been described. The choice of which approach is best for an individual depends on multiple factors including the type of surgery, part of the hip needing to be exposed, age and bone quality of the patient as well as the surgeon’s preference and expertise. Each of these surgical approaches have unique advantages both for the patient and for the surgeon. Generally speaking, a successful THR can be safely performed by a qualified orthopaedic surgeon through any approach. Talk to your surgeon about which approach is right for you.

“Minimally Invasive Surgery”
Several years ago, the term “minimally invasive surgery” or “MIS” was coined to reflect the use of a dramatically shorter incision utilized during joint replacement surgery. Unfortunately, as “MIS” techniques increased so did the reported surgical complications, including longer surgery times, fractures, poor component placement and fixation, all of which resulted in early failures and the need for reoperation.
Certainly, every effort should be made by the surgeon to limit the incision length as well minimize the extent of bone and soft tissue injury to only that which is absolutely necessary to perform the procedure effectively. However, it is our opinion that the term “minimally invasive” has been improperly used as a marketing tool by some surgeons aiming to boost surgery volume and attract patients in competitive markets.
There is nothing minimally invasive about a surgery that replaces a large joint and can potentially result in life-altering complications. Though the length of incisions has decreased over time, we no longer measure success by striving to make very small incisions. We contend that incision length is just one of many important considerations in THR.

Blood Loss Reduction
In years past, due to the significant blood loss during surgery, patients routinely required a blood transfusion after surgery. Transfusions became so common that patients and/or family members of the patient were required to “pre-donate” their blood to provide for a needed transfusion. This process was very costly and often the donated blood was simply wasted. This practice is no longer utilized.
Due to improved surgical techniques and the use of a medication called tranexamic acid (TXA) given at the time of surgery, blood loss is relatively low and the need for a blood transfusion is quite rare. TXA is a medication that reduces the body’s natural tendency to break down blood clots and thereby reduces bleeding during and after surgery. In select cases, a surgeon may elect to save and reuse or “recycle” your own blood that is lost in surgery through a process called “Cell-Saver”.

Reduction of Inflammation
Both before and in the days after surgery, anti-inflammatory medications are utilized to decrease pain and swelling. The use of Decadron (a steroid) and Celebrex or Meloxicam help tremendously to reduce postoperative pain and swelling. Studies have demonstrated that the use of these medications (particularly Decadron) before and after surgery decreases pain, narcotic use, nausea and length of hospital stay. These medications are well-known, cost-effective and safe for use by most patients except in those individuals with certain medical conditions.

Anesthesia and Pain Control
Another area of significant advancement has been in the delivery of anesthesia and pain control. An anesthesiologist is responsible for making patients comfortable before, during and immediately after surgery. Whenever possible, “spinal” anesthesia is recommended as opposed to a “general” anesthesia as it is quite safe and does not require one to be intubated.
Extensive research and study has demonstrated that spinal anesthesia in joint replacement results in less pain, bleeding, and postoperative nausea and confusion with patients experiencing faster return of function and recovery. Patients are more alert and ready to participate in therapy. Spinal anesthesia can also be accompanied by a nerve block and/or local injections of anesthetic in and about the hip joint which can further reduce pain after surgery without the need for narcotics.
Experiencing some pain after hip replacement is anticipated and is completely normal. However, we use a multimodal pain management protocol to help control pain which includes the anti-inflammatory medications (i.e. Decadron, Celebrex/Meloxicam) as well as acetaminophen (Tylenol), Tramadol, Norco (oral narcotic) and a muscle relaxant. Intravenous (IV) morphine and like medications are reserved for intense and immobilizing pain. The use of spinal anesthesia, nerve and local blocks combined with oral medications that work synergistically to control pain, IV pain medications are typically not necessary and the well-known side effects of narcotics (i.e. nausea, sedation, addiction) can be avoided.
Using this approach, our patients are typically able to discharge home from the hospital the day after surgery and in some cases may be able to go home the same day. This is in stark contrast to years ago when staying 3-5 days in the hospital or the need to be discharged to a skilled nursing facility were the norm. In fact, total knee replacement (TKR) is no longer listed as a Medicare inpatient-only procedure (IPO) and it is anticipated that in the near future the majority of joint replacement surgery in the US will be done on an outpatient-basis.

New Thoughts on Anticoagulation
One of the risks of surgery is the potential for developing blood clots which can be harmful and/or even life threatening. For years, THR patients were vigorously anticoagulated with blood thinners after surgery as surgeons feared clots could be fatal if they travel to the lungs. Drugs that were commonly used include Coumadin and Heparin which were difficult to monitor or administer. Studies now show that most healthy patients can be treated with aspirin to prevent blood clots without the risk of unwanted bleeding and higher cost. We assess the individual risk of blood clot for each patient and are less aggressive than years past which has resulted in fewer patients experiencing excessive bleeding and infection.

Computer Navigated and Robotic Assisted Surgery
Though computer navigated and robotic assisted surgery has been around in some form for many years, the use of this technology has rapidly increased and dramatically improved. In years past, the use of these technologies had failed to demonstrate clear advantages in routine cases over traditional techniques and was often associated with higher costs and longer surgical times. More recently however, computer navigation and robotic assisted surgery have merged and significant improvements have been made. One product that we use frequently with great success in select cases is commercially known as MAKOplastyⓇ. MAKO is very effective in preparing bone and assuring optimal implant alignment and cup placement in THR. We are actively involved in the evaluation and clinical application of similar technologies and feel that these will continue to be valuable tools that will aid in our effort to provide our patients with the highest quality care.

Importance of High Surgical Volume
Many studies have demonstrated that higher surgeon and hospital surgical volume are correlated with lower complications and lower costs after THR. Though no “magic number” has been determined, we perform hundreds of primary and revision joint replacements every year and both Memorial Medical Center and HSHS St. John’s are high volume joint replacement centers.

Life-Long Follow-up of Prosthetic Joints
All joint replacement patients should have periodic follow-up with x-rays throughout their lives. Joint bearings will wear very slowly with time which can lead to a poor functioning hip replacement. In some rare cases, wear particles generated by older bearings can cause a reaction by the body, which in turn, can lead to the destruction of bone an soft-tissue around the implant resulting in failure of the entire THR. Fortunately, if this process is identified early-on the bearings can be replaced with a relatively minor surgery.

Antibiotics Prior to Dental Procedures
Dental procedures or other interventions can allow bacteria to enter the bloodstream; therefore, it is recommended that joint replacement patients take preventive antibiotics prior to these procedures. While there is no clear consensus, most physicians would agree that patients should take antibiotics for a period of at least 2 years following joint replacement. For those individuals at higher risk of infection (i.e. diabetic patients), we currently recommend our patients use antibiotics whenever they see the dentist, indefinitely.

Complications
There are many potential complications of hip replacement, but fortunately the incidence is low. Complications include leg length discrepancy, injury to nerves that can result in muscle weakness and loss of sensation, infection that may require the removal of the implant and fracture of the bone during surgery or afterwards. A fracture may require protected weight bearing or even another surgery. Blood clots (DVT/PE), strokes and heart attacks may be life threatening or even fatal. Injury to blood vessels is a rare but serious event. Dislocation of the prosthetic joint is a complication that could become recurrent and require further surgery. Patients, on occasion, are dissatisfied with their outcome but generally speaking total hip patients are very satisfied with their results.

Conclusion
THR is largely a very successful and life-changing surgery; however, the decision to proceed with surgery should not be taken without first ensuring that the patient candidate is medically optimized and that a high volume, experienced joint replacement surgeon and facility are selected. By so doing, the chances of a successful outcome are maximized and the risk of complications are minimized.