The 2-incison THA is a novel surgical technique that combines two standard orthopaedic surgical approaches with fluoroscopic guidance, conventional hip implants and specialized instrumentation. The goal of this procedure is to minimize soft tissue trauma, thereby reducing postoperative morbidity and accelerate rehabilitation.

The surgical procedure is performed with the patient supine on a radiolucent table. Two separate, 4-5 cm incisions are used to create a direct pathway to the acetabulum and the femur. An oblique incision along the femoral neck allows the acetabulum to be exposed through a traditional Smith-Peterson approach. This surgical interval is both internervous and intermuscular and therefore requires no muscle dissection. After removal of the femoral head, the entire acetabulum can be visualized, prepared with specialized reamers and a conventional cementless cup and liner can be implanted with an offset inserter. Aside from the skin incision and femoral neck cut, fluoroscopy is not essential for exposure and implantation of the acetabular component.

The second incision is used to prepare and implant the femoral component.  A point coaxial to the femur in both the coronal and sagittal planes is used to create an oblique incision in the posterior lateral buttock. Using both the anterior and posterior incisions, a pathway from the posterior incision, through the piriformis fossa and into the femoral canal is created. This surgical approach is analogous to a femoral rodding and requires only incising the Gluteus Maximus fascia and a small split in the muscle. Then with the aid of fluoroscopy, palpation and direct visualization from the anterior incision, the femur is prepared with specialized instrumentation and a conventional cementless femoral component is implanted. The prosthetic neck is then brought through the capsule with traction to allow placement of the head and reduction of the hip through the anterior incision.

8:26 a.m.

Anterior Approach for THA on the Orthopedic Table

Joel M. Matta, M.D., Tania Ferguson, M.D. and Cambize Shahrdar, M.D.

The anterior approach is also called the Heuter Approach or the Short Smith-Pete Approach. It is performed on the OSI PROfx table to facilitate femoral access.  It is minimally invasive because it preserves the muscle attachments to the pelvis and femur and also does not disrupt the “Hip Deltoid”.  I adopted this technique to minimize the chance of post-op dislocation and to accelerate the recovery rate.

From September 1996 through September 2004 I performed 651 anterior approach THA including 523 primaries (the subject of this report), 98 hips with previous surgery, and 29 revisions.

This is a consecutive unselected series of 523 primary THA in 465 patients (58 bilateral).  The maximum BMI is 57.  Operative time averages 1.5 hours.   The incision length averages 10 cm.  Leg length discrepancy averages 3 mm, with a standard deviation of 4 and a maximum of 10 mm.  Acetabular abduction averages 41° with a standard deviation of 4 (range 33° to 49°).  Acetabular anteversion averages 23°, with a standard deviation of 5 (range 9° to 38°).  Complications include: 1 infection, 2 anterior dislocations, 1 posterior dislocation, 0 recurrent dislocations, and 1 femoral nerve palsy (recovered).

The time for patients to begin walking without external support at a median of 8 days.  Patients terminate the use of external support at a median of 15 days.

The anterior approach requires no post-op dislocation precautions and facilitates early functional recovery.  It is a minimally invasive technique applicable to all primary hip patients, does not increase complications or operative time or compromise accuracy of acetabular position or leg length.

Consult: www.hipandpelvis.com

8:32 a.m.

Minimally Invasive Total Joint Arthroplasty

Conservative hip surgery has lost popularity in the seventies of the last century although some centers have continued to perform osteotomies around the hip. Today, conservative hip surgery can be defined as the surgical treatment of prearthritic deformity and/or of early osteoarthritis of the hip by preserving the biological joint. Hips with established osteoarthritis are not anymore an indication except for situations where alignment is the problem and pain is little. While proximal femoral osteotomies are constantly decreasing in number, some indications remain strong, especially valgus-type osteotomies in post traumatic deformities and non-unions near the hip. Pelvic osteotomies have gained increasing interest during the last 20 years but only the few powerful reorientation procedures have been performed in bigger numbers.

During the last 10 years the impingement concept for the origin of osteoarthritis of the hip has been established. This was possible with a safe technique of surgical dislocation of the hip joint allowing not only new insights into the pathoanatomy but opening a door to a new generation of intra- and juxtacapsular reconstruction procedures. Some of these procedures are already established like the acetabular resection osteoplasty, the debridement and refixation of the labrum as well as the head contouring osteochondroplasty. If the deformity is not too global, the described steps are more and more performed with arthroscopy or with a semi-open procedure. Other techniques are about to emerge from early clinical testing like relative neck lengthening, subcapital reorientation of the slipped epiphysis, femoral neck osteotomy and finally femoral head reduction osteotomy in post Perthes coxa plana.

The different techniques which all depend on precise knowledge of the vascular anatomy are presented.

9:17 a.m.

Femoral and Acetabular Osteotomy

Richard Santore, M.D.

Both femoral and acetabular osteotomies have enduring useful roles in the surgical management of patients with various hip conditions. The original, and ongoing, indication for intertrochanteric valgus osteotomy is to induce healing of femoral neck non-unions by converting the high shear forces of a vertical fracture into compressive forces by repositioning into a more horizontal position. Avascular necrosis of the head, in the absence of segmental collapse and secondary arthritis, is not a contraindication to such a valgus osteotomy (Marti). Additional indications for intertrochanteric osteotomies include post-traumatic deformity, limb length inequality, adult sequellae of Legg-Calve-Perthes (high riding trochanter, shortening and varus), grade II posterior head displacement, apparent varus, and malrotation/impingement due to Slipped Capital Femoral Epiphysis, and certain cases of osteonecrosis. Isolated intertrochanteric osteotomy is only occasionally indicated for the management of arthritis secondary to dysplasia.

Rotational osteotomy of the pelvis (Bern or Ganz-type periacetabular osteotomy, Tönnis or juxta-articular type or dome type) has overtaken the role once historically played by intertrochanteric osteotomy in the surgical management of dysplasia-related hip anomalies. It is imperative that the hip joint be congruous, free of fixed subluxation and located in the native, not false, acetabulum. Ideal candidates have pre-arthritic, activity related pain associated with radiographic dysplasia. Early arthritic (Tönnis I) is not a contraindication. Surgical management of associated acetabular labral tears/detachments, and impingement lesions can be done at the same time via antecedent hip arthroscopy (same anesthetic) or open arthrotomy. The nature of the dysplasia, i.e. global, or primarily frontal plane, or primarily anterior, needs to be assessed pre-operatively with specially obtained plane radiographs that include a conventional AP, a standing AP pelvis, an AP hip in internal rotation/abduction, a false profile and a lateral. Any associated retroversion has to be assessed. CT scan is often helpful. The directions of the coverage enhancements and their magnitudes need to be customized to fit the nature of the dysplasia. A ‘standard’ method of correction is likely to result in unwanted iatrogenic retroversion is some cases; especially if a pre-existing retroversion has not been taken into account. Intertrochanteric osteotomy is now used as a complement to rotational osteotomy at a rate of approximately one in ten cases, for the indications outlined above. In most cases, the pelvic and intertrochanteric osteotomies are done under the same anesthetic.

All osteotomies should be done with the concept that conversion to total hip replacement might be necessary in the future. Displacements, osteosynthesis and hardware removal should be planned in such a way as to minimize future technical difficulties. Femoral and Chiari osteotomies can pose great difficulty at the time of conversion if major displacement were performed. In the event of iatrogenic severe retroversion after a periacetabular osteotomy, it may be desirable, in fact essential, to perform a reversal of the PAO before the THR, in order to avoid major malposition of the acetabular component that would be the source of untreatable recurrent dislocation.

9:25 a.m.

Hip Arthroscopy

Joseph C. McCarthy, M.D.

Hip arthroscopy is an excellent way to evaluate, diagnose, and treat an evolving number of hip conditions including loose bodies, synovial chondromatosis, post trauma, foreign body removal, and post total hip arthroplasty.  Radiographic studies are not sensitive enough; however, contrast agents used in conjunction with CT and MRI may aid in the diagnosis of intra-articular hip pathology.  Labral tears are the most common cause of mechanical hip symptoms. A review of 1246 cases revealed 98% of all labral tears and 95% of all chondral lesions occur in the anterior quadrant.  The most frequently observed chondral lesion is the watershed lesion, which consists of a labral tear with separation of the labrum from the articular surface at the labral-cartilage junction. The severity of the chondral lesion is highly correlated with the surgical outcome. The lateral approach requires that the patient be positioned in the lateral decubitus position with the affected hip up.  Most intra-articular lesions occur in the anterior quadrant (medial or superior) of the hip and can be treated via two superior paratrochanteric portals.  The paratrochanteric portals pass through fewer muscle planes, avoid potential injury to the adjacent neurovascular structures, and punctures the superior hip capsule which is slightly thinner. A thorough knowledge of positioning and anatomic relationships to portal placement is necessary to prevent potential neurovascular complications from occurring during hip arthroscopy.   Complications are best avoided by sufficient distraction (7-10mm), dedicated hip instruments, and precise surgical skills.  Further improvements in instruments and long-term outcome measurements will define and clarify the role of arthroscopic hip surgery.

9:33 a.m.

Fusion of the Adult Hip

Dennis. W. Burke, M.D.

Despite remarkable advances in the technology of total joint arthroplasty, arthrodesis of the adult hip remains a viable option in selected individuals.

The major indications for hip arthrodesis are unilateral hip disease in adolescents with closed growth plates or in the young adult.  Further requirements are that the patient be motivated and have a full understanding of the scope of the surgery, the details of recuperation and long term function patterns.  Some contraindications to hip fusions are bilateral hip disease, significant back or ipselateral knee disease.  A person with avascular necrosis should have a quiescent interval of 18 months with a negative MRI on the contralateral hip before proceeding with hip fusion.  Reasons which are not contraindications to hip fusions are the female gender, the height stature of a patient or avascular necrosis as a disease entity as long as the contralateral hip has been proved normal by an MRI.

The techniques are many and variable.  The so-called cobra technique is an established and proven technique of high success rate.

One of the essential technical aspects of hip arthrodesis is positioning.  The ideal hip position of the hip fusion is 30 degrees of forward flexion, neutral or slight abduction of the hip and slight external rotation of the hip.  Even a solid arthrodesis will have a poor functional outcome if it is in the wrong position.  Although after a hip arthrodesis the abductors have little function, it is important to preserve their attachment for potential later conversion to a total hip replacement. The “double bean bag” technique of positioning is quite useful and allows accurate reproducible positioning of the hip during the fusion operation.

A cobra plate is used to gain internal fixation.  Male and female bell type reamers are used to conform the acetabulum and femoral head. Be sure to ream the head first. The abductors are preserved by performing a trochanteric osteotomy and reattaching the trochanter over the cobra plate.

9:41 a.m.

Algorithm for Nonarthroplasty Surgery of the Hip

John C. Clohisy, M.D. and Perry L. Schoenecker, M.D.

The management of adolescent and young adult hip disorders has rapidly evolved over the past decade. This is due to enhanced understanding of pre-arthritic and early arthritic hip disease combined with improved diagnostic skills, better patient selection criteria and refinements in alternative surgical techniques. Despite this, there remains a major need to develop optimal diagnostic and treatment algorithms for young patients with compromised hip function. It should be emphasized that comprehensive care of young adult hip patients must employ a diversity of surgical techniques including arthroscopy, osteoplasty, surgical dislocation, pelvic osteotomies, femoral osteotomies, grafting procedures, arthrodesis and prosthetic replacement. Optimal clinical results are dependent upon the combination of careful patient selection and successful execution of the appropriate surgical procedure. The purpose of this presentation is to outline an algorithm for the diagnosis and treatment of adolescent and young adult patients with symptomatic disorders of the hip.

Detailed history, physical exam and imaging of the hip are essential to develop an optimal surgical strategy for the patient. Initial evaluation must confirm the hip joint as the source of clinical symptoms. A symptomatic hip in the absence of a significant osseous deformity (isolated labral tear, loose body, chondral flap) can be managed effectively with hip arthroscopy. In the presence of an osseous abnormality and a mechanically jeopardized hip, the planned surgical procedure addresses the bony deformity in conjunction with treating the associated intra-articular disease. Such procedures (osteoplasty, debridement and osteotomy) are utilized to treat impingement lesions (reduced head-neck offset, aspherical femoral head, retroverted acetabulum, SCFE) as well as joint overload disorders (classic DDH, Perthes-like deformities). The endstage arthritic hip in the young patient presents a difficult clinical problem that is most commonly treated with prosthetic replacement surgery, yet hip arthrodesis remains an option for the occasional, carefully selected patient. A comprehensive treatment strategy, utilizing a variety of surgical techniques, should provide effective management for the wide spectrum of hip disease encountered in this very challenging patient population.        

10:02 a.m.

Presidential Guest Speaker :

Metal-Metal THR has the longest clinical history of any of the currently used articular couples. Long-term follow-up of what are now considered sub-optimal designs (e.g., McKee Farrar, Ring, Sivash) has produced a wealth of knowledge regarding the safety and efficacy of this articular combination.

Retrieval analysis of metal-metal THR articular couples have demonstrated wear between 1 and 5 microns per year, after initial wear-in, in comparison with 100-­200 microns per year associated with metal-polyethylene wear. Equally important, the histologic response to metal wear debris (which are substantially smaller than polyethylene wear debris) is not associated with a histiocytic response as seen with polyethylene wear, and thus, is rarely associated with osteolysis.

The constituent metal ions released through wear of the metal-metal THR are excreted primarily in the urine, and in general the serum levels have been 3 to 5 times higher than control subjects. However, cobalt and chromium serum levels are also seen in patients who have metal-polyethylene couples in conventional THR or TKR. No adverse physiologic effects have been identified in the long-term follow-up of patients exposed to cobalt-chrome implants.

10:48 a.m.

Avoiding Femoral Fractures in Total Hip Resurfacing

Thomas P. Schmalzried, M.D.

Total hip resurfacing with metal-metal bearing components is considered investigational by the Food and Drug administration.  To date, a total of 147 hips have been implanted by the senior author in 121 patients using the Conserve Plus hybrid hip resurfacing system (cementless socket; cement femur) under an FDA and IRB approved protocol.  This is the initial cohort of patients treated with metal-metal resurfacing by this surgeon.  Eighty-one hips in 70 patients have a minimum of 2 years follow-up, with a maximum follow-up of 50 months.  There have been no femoral fractures.  There was one femoral component that was radiographically loose at 12 months and revised at 17 months post-op.  All other components are in situ.

Careful case selection and minimizing surgical trauma can reduce the occurrence of femoral neck fractures, even in the surgeon’s initial experience.  Pre-operative characteristics of the low-risk proximal femur include favorable shape (head:neck >1.2 and neck length >2cm); good bone density; no cysts >1cm; and favorable mechanics (>120 valgus).  Valgus and anteversion positioning, with anterior/superior translation of the femoral component, minimizes tension stresses on the neck.  Intra-osseous proximal femoral suction keeps the bone dry and promotes consistent cementing.  Aggressive impaction during the insertion of femoral components can be avoided by assuring adequate clearance at the implant-bone interface.

10:56 a.m.

Highly Cross-Linked Polyethylene

William J. Maloney, M.D.

Highly cross-linked polyethylene has now been commercially available for approximately five years.  Currently the majority of polyethylene inserts that are implanted in North America are highly cross-linked products.  Clinical data is now available on several of these implants.  Although there are fundamental differences between the commercially available products in terms of manufacturing technique and sterilization, wear testing has been encouraging.  Randomized clinical trials have demonstrated that the various highly cross-linked materials have lower wear rates than their conventional counterparts approaching in some cases what was seen in the laboratory.  There have been no reports of rapid wear or premature osteolysis at this time.

Concerns over the mechanical properties are ongoing.  There has been a very small number of liner fracture which appear to be more a factor of the unintended consequences of the use of large femoral heads with unsupported polyethylene and not specifically related to the mechanical properties of the highly cross-linked material.  Finite element studies have shown that in the conditions in which fractures have been clearly documented, conventional polyethylene would have also failed.

11:04 a.m.

Oxinium on Cross-Linked PE

Several wear studies have noted that cross-linked polyethylene is less resistant to a roughened counterface.  It seems reasonable to select the most scratch resistant counterface to articulate against cross-linked polyethylene in patients who are expected to outlive their total hip arthroplasties.  Both ceramic and Oxinium femoral heads seem well suited to this role.  Oxinium femoral heads have all the advantages of ceramic without the risk of fracture.

11:12 a.m.

THA: Alumina-on-Alumina Ceramic Bearings: 3-7 Year Follow-up

Surgeons have a strong influence on patient choice in anesthetic type.  Newly developed catheters for continuous medication delivery, specialized infusion pumps, and expertise in the field of Anesthesiology have made regional anesthesia more attractive to patients and surgeons.  Regional anesthesia for major lower extremity reconstruction includes the use of single shot and continuous epidural injection, single shot and continuous spinal injection, continuous lumbar plexus blockade, and continuous peripheral blockade of the femoral and sciatic nerves.  These developments have led to the application of regional anesthetic technique in conjunction with major lower extremity reconstructive procedures such as multi-ligament knee reconstruction, tibial osteotomy, unicompartmental replacement, ankle fusion, and ankle replacement, as well as hip and knee replacement.  Surgeons without experience in the use of regional anesthesia are hesitant to adopt the technique because of perceived inefficiency and prolonged room turnover, while also indicating great satisfaction with the pain relief provided by continuous peripheral nerve blockade.  Recent evidence indicates a high degree of reliability, safety, effectiveness, and patient satisfaction with regional anesthesia.  Widespread adoption of regional technique will require continued demonstration of safety, the possibility of early mobilization with weight-bearing, the early return of proprioceptive function, and system efficiency.

11:42 a.m.

Postoperative Pain Management

Douglas A. Dennis, M.D.

Successful management of perioperative pain is critical for accelerated rehabilitation following total hip arthroplasty (THA).  Perioperative pain management programs must minimize pain without creation of excessive sedation or motor blockade while avoiding treatment complications.  A multimodal program including method of anesthesia and postoperative pain management is necessary to maximize patient recovery.

Numerous methods of anesthesia are available for use in THA including general and various methods of regional anesthesia (spinal, epidural, lumbar plexus blocks, etc.).  Regional anesthesia offers the advantage of continued analgesia postoperatively by use of intrathecal opiods, continuous epidural infusions, or peripheral nerve blocks and has been shown to reduce postoperative pain and the need for parenteral opiods.  Postoperative epidural infusions of either local anesthetics or opiods can be utilized.  Epidural administered Ropivicaine has been shown to lessen motor blockade when compared with Bupivacaine.  Potential complications associated with regional anesthetics include nausea, pruritis, and urinary retention.

Understanding that pain is mediated via neurogenic and inflammatory pathways has resulted in improved analgesia following joint replacement.  Administration of preoperative medications (pre-emptive analgesia) such as nonsteroidal anti-inflammatory drugs (NSAIDs) and opiods which attempt to reduce sensitization of both the inflammatory and neurogenic pain pathways before surgical intervention has been shown to substantially reduce postoperative pain in numerous studies.  COX-2 NSAIDs are frequently chosen due to their reduced risk of interfering with anticoagulation regimens.

Lastly, use of cryotherapy, local wound injection (local anesthetics and opiods), and preoperative education programs are also valuable adjuncts in the treatment of postoperative pain following THA.

11:49 a.m.

Accelerated Rehabilitation for Total Hip Replacement

Richard H. Rothman, M.D., Ph.D.

The current focus of both patients and physicians is on rapid recovery, minimization of post operative pain, and improved function. These goals, although laudable, should never be secondary to excellence in long-term outcomes.

The strategies full in obtaining rapid return to recreational and occupational function include the following:

1. Surgical considerations include obtaining optimal stability, use of implants that are compatible with full weight bearing, gentle atraumatic surgery, and careful hemostasis.

2. Improved pain management encompasses minimization of injectable narcotics, oral analgesics, the use of anti-inflammatory drugs, local pain blocks and injections.

3. Patient selection and education is central. Morbid obesity and habituation to narcotics are contra-indications to a "fast track." Patient education, intensive physical therapy and inculcation of appropriate goals are all utilized.

4. A team approach is helpful and includes the surgeon, social worker, pain physicians, physical therapist, home-care coordinators, and the family.

5.  Critical care pathways should be well delineated and explained to families, patients, and the entire patient care team.

11:56 a.m.

Patient Education to Promote Success

Richard D. Coutts, M.D., Thomas R. Turgeon, M.D., Bindesh Shah, M.D. and Mary Elington, R.N.

Preoperative education programs have been used extensively in an effort to improve outcomes following total hip and knee arthroplasty.  Evaluations of length of stay, rate of discharge to home and complication rate were performed on consecutive patients from January to April, 1995 and 1996.  A mandatory multidisciplinary pre-operative education program was instituted in May, 1995.  Mean length of stay was reduced from 5.4 days to 4.7 days for primary hip arthroplasty (p=0.008) and from 5.6 days to 4.5 days for primary knee arthroplasty (p<0.001).  Discharge to home rates did not vary between the groups.  A significant reduction in the complication rate was seen among patients undergoing primary total knee arthroplasty (p=0.03), but not among primary hip arthroplasty (p=0.76).  The institution of a mandatory preoperative education program for total joint arthroplasty was associated with shorter hospital stays for both primary knee and hip arthroplasty as well as a reduced complication rate among total knee arthroplasty patients.

1:30 p.m.

The Otto Aufranc Award:

We retrospectively assessed whether heritable thrombophilia-hypofibrinolysis was more common in cases developing venous thromboembolism (VTE) after total hip replacement (THA) than among controls not developing VTE, as an approach to better identify causes of VTE after THA. Twenty cases with proximal deep venous thrombosis (DVT) following THA documented by magnetic resonance venogram (MRV), and 23 with symptomatic pulmonary embolism (PE) documented by ventilation/perfusion scan or spiral CT scan, were compared to 43 controls without postoperative VTE, after matching cases to controls by age, gender, body mass index, hip diagnosis, clinical predisposing factors, and VTE prophylaxis.  Measures of thrombophilia included the following gene mutations: G20210A prothrombin, G1691A Factor V Leiden, C677T and A1298C methylene tetrahydrofolate reductase (MTHFR), as well as serologic measures of thrombophilia (protein C, antithrombin III, and homocysteine). The hypofibrinolytic 4G/4G polymorphism of the plasminogen activator inhibitor-l (PAI-1) gene was also assessed. Five of 42 cases (12%) and 0 of 43 controls (0%) had antithrombin III deficiency (<75%) (p= .026). Nine of 42 cases (21%) and 2 of 43 controls (4.7%) had protein C deficiency (<70%) (p= .021). Ten of 43 cases, (9 heterozygous, 1 homozygous) (23%) and 1 of 43 controls (heterozygous) (2%) had the prothrombin gene mutation (p= .0037).  VTE cases were more likely than controls to have ≥ 1 abnormality of antithrombin III, protein C, or the prothrombin gene mutation (21/42 [50%] vs 3/43 [7%]) (p<0.0001), with sensitivity 50% and specificity 93% in distinguishing cases from controls. For our 1769 case cohort prevalence of VTE (2%), the predictive value of a positive test (≥ 1 abnormality of antithrombin III, protein C, prothrombin gene) was 12.8% and for a negative test 98.9%. Antithrombin III deficiency had 11.9% sensitivity and 100% specificity in distinguishing cases from controls; the predictive value of a positive test for antithrombin III deficiency was 100% and the predictive value of a negative test was 98.2%. The prothrombin gene mutation had 23.3% sensitivity and 97.7% specificity in distinguishing cases from controls; the predictive value of a positive test was 16.9% and the predictive value of a negative test was 98.4%. Deficiencies of antithrombin III (r= .25, p= .02) and protein C (r= .25, p= .021), and the prothrombin gene mutation (r= .31, p= .003) correlated with postoperative VTE. Having 1 or more abnormality of antithrombin III, protein C, or the prothrombin gene correlated with VTE status, r= 0.48, p < .0001. Cases who had VTE following THA were more likely than matched controls to have heritable thrombophilia with antithrombin III or protein C deficiency, or homo-heterozygosity for the prothrombin gene mutation. Pre-THA screening for these three tests of heritable thrombophilia should improve identification of patients with reduced risk of VTE, who may only need mild thromboprophylaxis, and those with heritable thrombophilia in whom prophylaxis should be more aggressive.

1:45 p.m.

The John Charnley Award (Award Paper B):

Total hip arthroplasty is an operation characterized by a strong predilection for thromboembolic complications with potentially life-threatening consequences. Charnley et al., in a series of 7,959 total hip replacements from 1962 to 1973, identified the overall prevalence of pulmonary embolism to be 7.89 per cent with a fatal outcome in 1.04 per cent. Similarly, in the early 1970's Coventry identified an overall prevalence of pulmonary embolism of 2.2 per cent in a series of 2,012 consecutive total hip arthroplasties; in a subset of patients who received no prophylactic anticoagulation, the prevalence of fatal pulmonary embolism was 3.4 per cent.  Nonetheless, at that time the average duration of operation was 2.4 hours, blood loss was 1,650 milliliters and an average of 1,144 milliliters of blood were transfused. Prophylactic anticoagulation with warfarin was started five days after operation and, on average, patients remained at bed rest for one week prior to walking and were discharged three weeks after operation.

During the last three decades substantial advances have been made in the technical aspects of performing total hip arthroplasty, the convalescence from the operation, and our understanding of the pathophysiology and prevention of venous thromboembolism associated with hip replacement. While no less controversial today, the prevalence of fatal pulmonary embolism with contemporary techniques of operation and perioperative management would appear to be on the decline. In the absence of anticoagulant prophylaxis, the rate of fatal pulmonary embolism has been reported to be 0.5 per cent following 1,162 total hip replacements in one study and even less when multi-institution health service databases are accessed from the United Kingdom.  In North America, a combination of warfarin prophylaxis, regional anesthesia and the collective use of predonated autologous blood, expeditious operation, and early mobilization would appear to have lowered the fatal pulmonary embolism rate further to less than 0.1 per cent.

1:50 p.m.

The Frank Stinchfield Award:

Some surgeons have suggested that a minimally invasive two-incision approach allows total hip arthroplasty (THA) to be done without cutting or damaging any muscle or tendon. To our knowledge that claim has not been supported by any published clinical or basic science data. The purpose of this study was to quantify the extent and location of damage to the abductor and external rotator muscles and tendons after two-incision and mini-posterior THA. Ten cadavers (20 hips) were studied. In each cadaver one side was randomly assigned to the two-incision group and the contralateral hip was assigned to the mini-posterior group. After inserting the total hip components the muscle damage was assessed using a technique described previously. Damage to the muscle of the gluteus medius and gluteus minimus was substantially greater with the two-incision technique than with the mini-posterior technique (p=0.004 and p=0.018, respectively). Every two-­incision total hip had measurable damage to the abductors, the external rotators, or both.  Every mini-posterior hip had the external rotators detached during the exposure and had additional measurable damage to the abductor muscles and tendon. This study does not support the contention that a two-incision total hip is done without cutting muscle or tendon. None of the two incision hips were done without cutting, reaming or damaging the gluteus medius or minimus muscle or external rotators.

2:25 p.m.

Component Removal

Daniel J. Berry, M.D.

Bone sparing, time efficient component removal is an important aspect of revision hip arthroplasty surgery.  In the last decade, a number of complimentary technologies have been developed which together allow quick, safe removal of most failed implants.

The presentation will include discussion of indications for each technique, technical tips associated with each technique, and where available data on safety and efficacy of each technique.

2:33 p.m.

The exact and complete removal of bone cement from the proximal femur is key for the stable anchorage of any revision stem. The most useful methods are: removal of the bone cement from cranially or wide opening of the femur meta-diaphysis. In contrary we are using a ventrolateral fenestration of the femur diaphysis. For this so-called Weber technique a window of 0.7 to 1.0 mm in width is cut longitudinally in the required length. It is positioned mostly above the distal part of the implant. The cement can be removed using a small drill and chisel. The cortical lid mostly is repositioned using vicryl sutures or titanium cerclage bands. This method can also be applied in cases where a cementless stem cannot be extracted. The advantages of the Weber technique are: the proximal femur end remains intact in the circumference and the femur diaphysis is not weakened to a greater amount because of the fenestration. For this reason, bypassing the fenestration area with the implant is not necessary when using an appropriate revision stem. The duration of operation is decreased compared to a closed intervention from proximally and the cement removal can be performed with more exactness under optical control.

2:57 p.m.

Impaction Grafting: Acetabulum and Femur

Miguel E. Cabanela, M.D.

Impaction grafting for hip arthroplasty revision has now been in use for two decades, both in the acetabulum and the femur.

In the acetabulum impaction grafting has not made inroads in the United States.  While the technique of impaction morselized cancellous allograft has been utilized primarily for cavitary deficiencies, this has been associated with the use of uncemented components and not, as originally described by Slooff et al. with cemented fixation of a polyethylene component. Thus, while morselized cancellous grafting of acetabulae has provided very satisfactory results, it truly does not follow the original Slooff technique. 

For femoral revision, both favorable and less favorable results have been reported with this technique, adapted to the femur from the original acetabular description, first by the Exeter group and popularized by them (Ling, Gie, Timperley).

For the past 12 years, we have reserved the technique of intrafemoral impaction cancellous allograft for patients with primarily cavitary diaphyseal and metaphyseal deficiencies associated with canal geometry or size that would render them less suitable for other femoral revision methods.  We have solved small associated segmental deficiencies with vicryl or Co-Cr mesh or with strut grafts. 

Our experience with the first 10 years of impaction grafting has yielded very satisfactory results when the procedure is performed carefully and the impaction is done vigorously so that a great deal of rotational and axial stability of the cemented component is achieved.  We have always utilized a collarless, polished tapered stems and never a rough surface stem.  Strut allografts have been used liberally for cortical bone defect coverage or simply for reinforcement of weak cortices.

Our only serious complications have been postoperative fractures, which have occurred about 10% of the time.  All fractures, in our experience, have been dealt with by internal fixation of the fracture with plate and strut graft at 90 degrees to each other and all have healed without any subsidence of the prosthesis or subsequent prosthesis revision. Since these fractures most commonly occurred just distal to the prosthetic tip, perhaps the use of long stem prosthesis may have decreased their incidence.

Other complications observed included intraoperative fractures related to bone quality and over-zealous impaction, postoperative dislocation (with a frequency similar than that occurring in other revision procedures), and infrequent nerve complications. 

While we continue to use impaction grafting for femoral revision, its use in our institution has significantly decreased. Reasons for this include the fact that is a time-consuming procedure and similar results can be achieved with faster techniques, and also the possibility of disease transmission due to the fact that multiple donors are required to obtain the large amount of graft usually necessary.

3:05 p.m.

Trochanteric Reattachment

Robert L. Barrack, M.D.

3:13 p.m.

Modular Stems

William Hozack, M.D.

Non-modular fluted tapered revision stems have enjoyed immense popularity in Europe. Wagner introduced his stem in 1987 as a means of treating severe femoral bone deficiencies. The tapered stem was designed to obtain fixation distally in the femoral canal beyond areas of significant bone damage. In cross-section, these stems had a number of titanium flutes projecting from the central stem core. These flutes created immediate rotational stability for the stem within the femoral canal, and ultimately allowed for osseointegration.

In summary, while non-modular fluted stems achieved reasonable clinical results, several problems have been identified: subsidence, lack of modularity leading to difficulty with leg length restoration, and instability related to inadequate offset of the Wagner design.

Modular fluted tapered stems have achieved some degree of popularity in the USA. The philosophy of the modular design is to allow solid impaction of the fluted stem to a position of complete stability, thus minimizing subsidence. Then the surgeon chooses one of several proximal bodies of different lengths (to eliminate leg length discrepancy), placed in optimal version (to maximize joint stability).

1. It is critical to prepare a precise taper within the femur to accept the tapered stem. Inadequate preparation due either to under-reaming or inadequate exposure will compromise the ultimate result.

2. The transfemoral osteotomy is a key aspect of the overall technique. Using a TFO, preparation of a precise cone within the femur to accept the femoral stem is facilitated. While a precise cone can be prepared without the TFO, it is not so reliably done.  The TFO also simplifies removal of components and cement. The osteotomy may also play a role in the regeneration of proximal bone stock seen with the tapered conical revision stems.
3. Place a cerclage cable just distal to the osteotomy site. This allows more security with respect to proper preparation of the femoral canal.
4. After placing the distal stem, use the proximal body trials to adjust for leg length, offset and stability. The proximal bodies should be porous coated to encourage proximal bone ingrowth. This will provide more proximal load sharing and also block the femoral canal from osteolytic debris.

The selection of a prophylaxis regimen is a balance between efficacy and the risk of bleeding. The selection of a prophylactic agent may be influenced by the duration of hospital stay, the type of anesthesia used and the pain management regimen. The purpose of this presentation is to review the available prophylactic agents and their efficacy and safety profiles. In addition, areas of controversy including: duration of prophylaxis, timing of prophylaxis screening will be reviewed.

3:42 p.m.

Infected Hip Replacement: Prevention, Diagnosis, and Treatment in 2005

Arlen D. Hanssen, M.D.

Prevention. The disciplined use of aseptic surgical techniques remains critically important and the use of prophylactic antibiotics remains the single most effective method of prevention. The association between surgical skills and the risk of deep periprosthetic infection has been reported in multiple studies. This is particularly important to recognize as new surgical techniques are introduced. Antibiotic-loaded cement has an optimum surface for colonization and prolonged subtherapeutic exposure to antibiotic allows mutational resistance to occur. The unresolved issues both regarding the nature of antimicrobial resistance necessitates further research into the interaction of antibiotic-loaded bone cement and bacteria. Newer strategies of local antibiotic delivery to provide higher and sustained levels of antibiotics include new methods of antibiotic attachment or integration into implanted prostheses. Various strategies to prevent the formation of bacterial biofilms and non-antibiotic modalities such as nanoparticulate silver coatings, which show high effectiveness against multiresistant bacteria, are being actively investigated as additional methods of infection prevention.

Diagnosis. Identifying low-grade infection in failed total hip arthroplasties remains a difficult task. Preoperative aspiration is still an important diagnostic tool and the continued use of standard culture techniques are required to determine antimicrobial susceptibilities of identified organisms. The more invasive tissue drill biopsy offers no advantage over aspiration in terms of bacterial accuracy and results in more false positives. The role of nuclear medicine in diagnosis of the infected joint replacement remains undefined. Histopathological assessment of periprosthetic tissues remains subjective and variable between institutions. Many organisms that are responsible for low-grade infection after total hip replacement are not recognized by routine culture. The increasing use of technologies to enhance a definitive diagnosis such as ultrasonification, polymerase chain reaction detection, and confocal laser immunoflourescence imaging have created the need for a consensus position regarding the actual definition of clinical infection as these technologies are associated with a higher rate of organism retrieval from removed implants. The clinical significance of these findings are yet unknown. The combined use of these diagnostic technologies in real-time is being investigated as an alternative to histopathological assessment. It has been suggested that definitive diagnosis should consider using a microbial or microscopic analysis of the surface of an explanted prosthesis.

Treatment.  Extensive surgical debridement remains the cornerstone for treatment of an infected hip prosthesis. Some of the prognostic variables leading to a higher cure rate with debridement and prosthesis retention are being identified. Staging algorithms based upon patient, wound, and organism variables are being developed to help modify treatment protocols. The utilization of high-dose antibiotic spacers between the time of implant removal and eventual reinsertion of another prosthesis, in a two-stage approach, has become the accepted standard of treatment. The use of direct-exchange techniques has continued to decline globally as patients are now presenting with an increasing incidence of resistant organisms and severe bone loss which increases the difficulty of treatment. In addition to the cure rate of infection now exceeding 90%, strategies to decrease complications such as a persistent limp and high dislocation rates need to be evaluated.

Future Directions.  Biofilms demonstrate poor antibiotic penetration, nutrient limitation and slow growth, and formation of multicellular colonies constituting a multi-layered defense whereby resistance seems to depend on multicellular strategies. Disabling biofilm resistance may enhance the ability of existing antibiotics to clear infections involving biofilms that are refractory to current treatments and recent studies have underlined the potential relevance of biofilm susceptibility testing. Novel techniques such as ultrasound or pulsed electromagnetic fields to augment the efficacy of antibiotics are being investigated. Clearer understanding of biofilms promises to improve the current efforts being directed toward prevention, diagnosis, and treatment.

3:49 p.m.

New Strategies to Prevent & Treat Hip Instability

John J. Callaghan, M.D.

Prevention and treatment of hip dislocation following total hip replacement is a tough problem for the surgeon and patient.  In addition the problem is multifactorial and complex.  Historically one percent of all primary total hip replacements required revision for dislocation and only 60% of those revisions were successful in preventing further dislocation.  Newer understanding of the problem and more varied prosthesis selection should help the surgeon achieve better outcomes in these patients.

Prevention is better than treatment.  Use of trial components, availability of more variety in acetabular liners and femoral offset components, use of femoral neck geometries which optimize impingement free motion, and the development of capsular repairs should and have lowered the prevalence of dislocation.

Just as prevention of dislocation has improved, the potential for better treatments are available today.  In the past, use of options such as replacing the acetabular component with a bipolar replacement were popular.  With the advent of modular components more options are available for treatment.  Especially with the availability of more wear resistant polyethylenes, thinner liners can probably be used safely.  Extended and offset liners, larger femoral heads, and constrained liners are all options to consider in the treatment of dislocation.  If acetabular shells are secure constrained liners can be cemented into the shell.  Better exposure techniques such as extended osteotomy can provide better soft tissue tensioning at the time of closure.  With the use of these newer prosthetic options and exposure techniques, dislocation following revision of a total hip replacement for dislocation should be reduced to less than 10 to 15 percent.

3:56 p.m.

Update On Computer Assisted Total Hip Arthroplasty

S. David Stulberg, M. D.

Computer assisted surgery is currently being developed to improve the accuracy and reproducibility with which total hip replacements are performed. It is also anticipated that computer assisted surgery will facilitate the ease and accuracy of various minimally invasive surgical techniques.

The need for increasing the accuracy and reproducibility of placement of total hip components, especially acetabular implants, has been clearly documented in the earliest evaluations of computer-assisted techniques. The usefulness of these techniques in dealing with soft tissue balancing issues, e.g. leg length and femoral offset, has also been described. 

The accurate identification of important anatomic landmarks presents a particular challenge to the development of navigation systems for total hip surgery. Both image-based and image-free computer assisted systems are currently being used to address this issue. As yet, there is not agreement on the most accurate and reproducible method for acquiring the anatomic information necessary for navigation of total hip surgical tools. However, the navigated instruments themselves, e.g. reamers, broaches, are now standardized and relatively user friendly.

The initial experiences with computer assisted total hip systems have confirmed their safety and reliability. Total hip implants, especially cups, can be inserted more reproducibly when navigation is used.  However, the validation of these results is still in progress. At the moment, this technology is still in its developmental stage.

4:03 p.m.

Current Role Of Total Hip Arthroplasty In Acute Fractures

Robert T. Trousdale, M.D.

Arthroplasty is the treatment of choice for the elderly patient with a displaced femoral neck fracture.  Arthroplasty options include hemiarthroplasty with a monopolar or bipolar femoral head or a total hip arthroplasty.  The advantages of hemiarthroplasty compared with total hip arthroplasty include a shorter operative time and a lower risk of dislocation.  The advantages of a total hip arthroplasty compared with hemiarthroplasty include the potential of less groin pain, less acetabular erosion, and potentially better pain relief and function.  Total hip arthroplasty appears to be a very durable procedure at our center.  The probability of survival of a prosthesis without revision for patients with acute femoral neck fracture was 95% at 5 years, 89% at 15 years, and 84% at 20 years.  At last follow-up (range, 10 to 20.4 years) 86% had no or mild pain.  The overall dislocation rate was 10%. 

Total hip arthroplasty for acute femoral neck fracture is a durable procedure with minimal pain at final follow-up.  The relatively high dislocation rate may be able to be decreased with meticulous closure techniques and the use of larger femoral head sizes.

4:10 p.m.

Charles A. Engh, Sr., M.D., Nobuto Kitamura, M.D.

This study used computed tomography (CT) to characterize the pattern of osteolysis associated with different total hip arthroplasty (THA) cup designs. CT images were obtained for 126 THAs at a mean follow-up of 10.9 years. We measured the volume of all of periacetabular bone defects using a validated CT software program. Bone defects were defined as osteolysis if they met three criteria: 1) a well-defined sclerotic border, 2) a clear communication between the defect and the joint space, and 3) no radiographic evidence that the defect existed prior to THA. The acetabular components were divided into five different types including: (1) cups with no holes; (2) cups with a single central hole; (3) cups with only a single central hole which had been plugged; (4) cups with multiple central holes; (5) cups with a central hole plus holes in the rim for additional screws. Linear and volumetric polyethylene wear was evaluated on a minimum of three postoperative radiographs using a validated computer-assisted technique. We identified 225 bone defects in 116 of the 126 hips. Of these, 184 lesions in 101 hips fulfilled all three criteria for osteolysis. Osteolysis occurred primarily through the central holes when only those holes existed. Lysis occurred only around the rim when there were no holes in the cup. When cups had both central and rim holes, the lysis occurred through both communication pathways. The lesions that communicated only through central holes and those that had multiple pathways tended to be larger. Among all THAs, there was only a moderate correlation between the total volumetric wear and total osteolysis volume (r=0.418, p<0.001). At a mean of 10.9 years postoperatively, none of the osteolytic lesions were associated with clinical symptoms or had become a source of complications.

In conclusion, communication pathways between lesions and the joint space are valuable for diagnosing osteolysis on CT. Lesion volume, three-dimensional location, and type of communication pathway to the joint can be determined by modern CT. These findings, which differed among cup designs, are useful for better understanding osteolysis and defining the optimal method of treatment.