Surface replacement of the hip was established in the 1970's as a bone preserving alternative to total hip replacement. However, problems with femoral neck fracture, osteolysis, and component loosening led to early failures and an abandonment of the procedure.

The modern generation of hip resurfacing, however, has improved upon past results with new implant designs and materials. Better surgical guides and a short femoral stem allow for more accurate placement of the implants. A metal-on-metal articulation creates a larger diameter bearing and avoids polyethylene wear debris. Also paramount in the recent successes of surface replacement are refinements in surgical techniques, leading to more accurate component positioning, avoidance of neck notching, and an appreciation of the femoral head blood supply. It has been well-established that surgeons with higher volumes of hip resurfacing operations have a lower complication rate. The mid-term results of these newer hip resurfacing devices, coupled with appropriate patient selection and good surgical technique, have been encouraging.

Although, more recently, surface replacement has come under fire because of the metal-on-metal articulation, the Australian National Joint Registry finds that a certain group of patients has greater survivorship with resurfacing than with total hip replacement. Additionally, the benefits of surface replacement include the preservation of bone, a lower dislocation rate, and potentially a higher activity level. Therefore, the presenter feels that surface replacement arthroplasty is still a viable option, for the right patient and surgeon.

Introduction

Patients presenting with osteoarthritis as late sequelae following pediatric hip trauma have few options aside from standard Total Hip Replacement (THR). For younger more active patients, Hip Resurfacing Arthroplasty (HRA) can be offered as an alternative. HRA has been performed in the United States over the past decade and allows increased bone preservation, decreased hip dislocation rates versus THR, and potential to return to full activities.

Patients presenting with end-stage hip arthritis as following prior pediatric trauma or disease often have altered hip morphology making HRA more complicated. Often Legg-Calve-Perthes (LCP) patients present with short, wide femoral necks, and femoral head distortion including coxa magna or coxa plana. There often can be acetabular dysplasia in conjunction with the proximal femoral abnormalities.

Slipped Capital Femoral Epiphysis (SCFE) patients have an alteration of the femoral neck and head alignment, which can make reshaping the femoral head difficult. In particular, the femoral head is rotated medially and posteriorly, reducing the anterior and lateral offset.

We present a cohort of 20 patients, with history of a childhood hip disorder (SCFE or LCP), who underwent HRA to treat end-stage arthritis. Fifty percent had prior pediatric surgical intervention at an average age of 11.

Introduction

Hip Resurfacing Arthroplasty (HRA) has been performed in the United States for over 10 years and is an alternative to standard Total Hip Arthropastly (THA). It is appealing to younger patients with end stage osteoarthritis who seek to maintain active lifestyles. Benefits of HRA versus THR include a larger femoral ball size, potential to return to impact activities, decreased dislocation rates, and restoration of normal hip biomechanics. Patients ≤50 years old are a particularly challenging patient group to treat with THA because of their young age and high activity level, and as such, are well-suited for HRA. However, there are limited reports in the literature about clinical, radiographic and functional outcomes for this patient cohort. We present results of a clinical investigation at our institution for this patient cohort with minimum 5-year follow up, including long term survivorship and outcome scores.

Nerve palsy occurring after elective primary total hip arthroplasty is a devastating complication because of its effect on motor strength, walking ability, potential for pain, and unexpected nature. In general, the nerve distribution involved is the peroneal branch of the sciatic nerve, and the level of involvement is usually mixed motor and sensory.

Prior publications have associated limb lengthening, dysplasia and use of the posterior approach to be associated with a higher incidence of nerve palsy. In the literature, the incidence of sciatic nerve palsy is estimated to be 0.2–1.9%.

We examined the rate of sciatic nerve palsy after THA performed by the joint replacement service at Hospital for Special Surgery between the years 1998 and 2013. Each case was matched with 2 controls that underwent THA and did not develop post-operative neuropathy. Controls were matched by surgical date having been within 7 days of their matched case's surgery date. Patient and surgical variables were reviewed using data from patient charts and the institution's total joint replacement registry. A multivariable logistic regression model was created to identify potential risk factors for neuropathy following THA while adjusting for potential confounders.

We found that, of 39,056 primary THA cases, there were 81 cases of sciatic nerve palsy, giving an incidence of 0.21%. The factors with the greatest odds ratios for nerve palsy were: history of smoking (OR=3.45); history of spinal stenosis (OR=4.45), and time of day of 1PM or later (OR=3.98). We did not find limb lengthening, dysplasia, or type of fixation to be associated with nerve palsy.

In conclusion, post-surgical neuropathy has a low incidence after primary THA, but at our institution, was associated with several factors. Spine-related comorbidities, such as spinal stenosis and lumbar spine disease, and smoking history should be closely monitored to inform the patient and surgeon for the potential increased risk of post-operative neuropathy following THA.

A total knee replacement (TKR) with instability is one in which the supporting soft tissues have failed or are unable to function due to component size and/or position. Instability following TKR can lead to the need for surgery in 10–22% of revision cases. Patients may complain of symptoms of giving way, difficulty climbing stairs, and the sensation that their knee may buckle under stress. Physical findings may include soft-tissue tenderness in the peripatellar and pes anserine regions, recurrent joint effusions, and joint laxity. The cause of instability after TKR should be determined pre-operatively so the problem may be corrected at the time of revision.

Instability after TKR may be due to component loosening, ligament rupture/incompetence, component malposition, mismatched flexion/extension gaps, or failure to correct ligament imbalance at the time of the index procedure. A common scenario after a cruciate-retaining TKR is that of PCL rupture, thus leading to instability in flexion and excessive posterior translation of the tibia. Other scenarios leading to TKR instability are pre-operative valgus alignment with MCL stretching, resulting in the post-operative recurrence of medial instability; or excessive resection of the posterior femoral condyles from undersizing of the femoral component, leading to laxity in flexion.

The treatment of instability after TKR generally requires component revision and balancing of the flexion and extension gaps. Isolated ligament reconstruction is not successful in the setting of a prosthetic joint due to the lack of inherent joint stability. At the time of revision, the surgeon must carefully assess the flexion gap; often posterior femoral augments must be used to upsize the femoral component and tighten the flexion space relative to the extension space; for this reason, isolated polyethylene exchange is not successful for flexion instability. For instability in the varus/valgus plane, rebalancing the knee by performing ligament releases and using a more stabilizing polyethylene insert may by sufficient.

The results of revision TKR for instability has been successful in the majority of cases, decreasing the symptoms of giving way and difficulty stairclimbing. A careful assessment of the varus/valgus stability of the prosthetic knee and the flexion/extension spaces at the time of revision TKR, along with the use of augments and more stabilised articulations, is mandatory in order to achieve good results.

Computer navigation is an attractive tool for use in total knee arthroplasty (TKA), as it is well known that alignment is important for the proper function of a total knee replacement. Malalignment of the prosthetic joint can lead to abnormal kinematics, unbalanced soft-tissues, and early loosening. Although there are no long term studies proving the clinical benefits of computer navigation in TKA, studies have shown that varus alignment of the tibial component is a risk factor for early loosening.

A handheld, accelerometer based navigation unit for use in total knee replacement has recently become available to assist the surgeon in making the proximal tibial and distal femoral cuts. Studies have shown the accuracy to be comparable to large, console-based navigation units. Additionally, accuracy of cuts is superior to the use of traditional alignment guides, improving the percentage of cuts within 2 degrees of the desired alignment.

Because the registration is based on the mechanical axis of the knee, anatomic variables such as femoral neck-shaft angle, femoral length, and presence of a tibial bow do not affect the results. The handheld aspect of this navigation unit allows its use without additional incisions or array attachment. Furthermore, the learning curve and usage time is minimal, supporting its use in primary TKA.

Femoral neck fractures continue to be one of the most common orthopaedic injuries treated today. Owing to the increased longevity of patients, enduring activity of older patients, and widespread osteoporosis in the population, there are more femoral neck fractures treated nowadays than ever before. Over 1 million femoral neck fractures were treated in the >65 year old population, in the United States, between the years 1991–2008.

The treatment of femoral neck fractures is unique because some fractures are amenable to internal fixation, while others require endoprosthetic replacement, either with a hemiarthroplasty or total hip replacement. Traditionally, less displaced fractures are treated with internal fixation; however, in younger patients, an attempt to fix the displaced fractures may be performed, in order to avoid a joint replacement in this population. The age at which an attempt at internal fixation is performed is still controversial, and treatment must be individualised to each patient. In general, patients younger than 60 would likely have internal fixation of the femoral neck fracture, rather than joint replacement.

The paradigm for the treatment of femoral neck fractures has been changing in the last 10 years, due to advances in implant technology, surgical technique, and scientific papers that have compared the results of all three treatment options. Larger diameter femoral heads in combination with highly crosslinked polyethylene, or dual mobility head options, provide greater joint stability today than was possible in the past, thus making THA a more appealing option. Furthermore, greater use of the direct anterior approach to THA may also reduce the post-operative dislocation rate, due to preservation of the posterior capsule and short external rotators.

Therefore, the author will propose the use of arthroplasty for displaced femoral neck fractures in patients younger than 60 years of age, owing to the reliability and reproducibility of THA over ORIF. Furthermore, the advances in arthroplasty materials and surgical techniques can restore function in this group of younger patients, with greater longevity of the implant than in the past.

Perioperative blood conservation remains an important topic today in order to reduce complications, improve function, and facilitate recovery after a total knee replacement (TKR). Studies have shown that the degree of postoperative anemia is related to an increase in complications. A greater blood loss and need for transfusion is associated with a higher risk of infection, a slower recovery process, increased morbidity to patients, as well as an increased cost to the healthcare system.

Typical blood loss estimates range from 800cc to over 1700cc, when accounting not only for intraoperative but postoperative blood loss. Several strategies have been developed to help mitigate the risk of perioperative blood loss and need for subsequent transfusion.

Firstly, preoperative measures such as vitamin and mineral supplementation can ensure the starting hemoglobin and red cell count are maximised. Additionally, erythropoietin can be helpful in refractory cases of preoperative anemia. Preoperative autologous blood donation was used extensively in the past, but has fallen out of favor due to its inefficiency and cost.

Intraoperatively, measures such as the use of a tourniquet, meticulous technique, and expeditious surgery can help reduce blood loss. The most effective method, however, has been the use of tranexamic acid (TXA). TXA, an antifibrinolytic compound, has been extremely effective at reducing perioperative blood loss without increasing the risk of thromboembolic events. TXA can be used topically or intravenously. Other methods that can reduce intraoperative blood loss include the use of fibrin sealants, applied to the soft tissues and bony surfaces around the knee.

Postoperatively, the avoidance of wound drains is associated with a higher blood count and reduced transfusion risk. Alternatively, drainage reinfusion systems can be used to raise the postoperative blood count, particularly in cases of bilateral TKR.

Computer navigation is an attractive tool for use in total knee arthroplasty (TKA), as it is well known that alignment is important for the proper function of a total knee replacement. Malalignment of the prosthetic joint can lead to abnormal kinematics, unbalanced soft-tissues, and early loosening. Although there are no long term studies proving the clinical benefits of computer navigation in TKA, studies have shown that varus alignment of the tibial component is a risk factor for early loosening.

A handheld, accelerometer based navigation unit for use in total knee replacement has recently become available to assist the surgeon in making the proximal tibial and distal femoral cuts. Studies have shown the accuracy to be comparable to large, console-based navigation units. Additionally, accuracy of cuts is superior to the use of traditional alignment guides, improving the percentage of cuts within 2 degrees of the desired alignment.

Because the registration is based on the mechanical axis of the knee, anatomic variables such as femoral neck-shaft angle, femoral length, and presence of a tibial bow do not affect the results. The handheld aspect of this navigation unit allows its use without additional incisions or array attachment. Furthermore, the learning curve and usage time is minimal, supporting its use in primary TKA.

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (Co-Cr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10-year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated Co-Cr stem. One study utilising pain drawings did establish that if a Co-Cr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications.

Dislocation is a particular problem after total hip replacement in femoral neck fractures and elderly especially female patients. The increased rate of dislocation in this population is probably due to significant ligamentous laxity in these patients and poor coordination and proprioception. Another population of patients with increased propensity for dislocation is the revision hip replacement patient. Current dislocation rates in these patients can approach 10% with conventional implant systems.

The Dual Mobility total hip system is composed of a cobalt chrome acetabular shell with a grit blasted, beaded and/or hydroxyapatite coating to improve bone ingrowth. The polyethylene liner is highly cross-linked polyethylene and fits congruently into the cobalt chrome shell and acts like a large femoral head (usually >40mm). The femoral head attached to the trunnion is usually 28mm or 32mm. The femoral head snaps into the polyethylene liner to acts as a second protection against dislocation.

Indications for the Dual Mobility socket are in the high risk for dislocation patient and particularly in elderly female patients. One hundred fifty-six patients with an average age of 79 have been performed to date with a maximum follow up to 4.2 years. To date there have been no mechanical or septic failures and no dislocations. Pain relief has been no different than conventional hip replacement and range of motion is unchanged as well. There have been reported cases of intraprosthetic dislocation but these have not occurred to date.

Wound complications are much more common following knee arthroplasty as compared to hip arthroplasty, due in part to the precarious blood supply to the knee, as well as the subcutaneous position of the joint. Many, if not most, infections are related to wound problems, and thus avoiding wound problems is a critical issue in knee replacement surgery.

Many wound problems are avoidable and can be minimised by care to detail by the surgeon. The important steps are to first identify patients at risk and optimally addressing these risk factors. Patient risk factors include: chronic corticosteroid use, diabetes, rheumatoid arthritis, malnutrition, obesity, and smoking.

Soft tissue handling is a second major issue. Minimal incision surgery should be used with great caution for knee replacements since the skin is much less forgiving than in hip replacements. A midline skin incision should be utilised when possible. When multiple incisions are present it is usually advisable to use the lateral most incision through which it is feasible to perform a knee replacement. In rare cases, a soft tissue expander may be used preoperatively for thin, adherent skin.

Perioperative steps that can be taken include delaying CPM in high risk wounds, and using a wound vac system in obese or other high risk wounds to minimise persistent drainage. Furthermore, anticoagulation should be used judiciously to avoid prolonged drainage. The final step in salvaging the problem wound is early recognition and aggressive management of wound healing problems. Prolonged, serous drainage is the most common clinical scenario. Drainage that is increasing beyond 5–7 days frequently requires evacuation, irrigation, debridement, and liner exchange. Early aspiration can decompress a hematoma and also rule out infection.

Wound complications are much more common following knee arthroplasty as compared to hip arthroplasty, due in part to the precarious blood supply to the knee, as well as the subcutaneous position of the joint. Many, if not most, infections are related to wound problems, and thus avoiding wound problems is a critical issue in knee replacement surgery.

Many wound problems are avoidable and can be minimised by care to detail by the surgeon. The important steps are to first identify patients at risk and optimally addressing these risk factors. Patient risk factors include: chronic corticosteroid use, diabetes, rheumatoid arthritis, malnutrition, obesity, and smoking.

Soft tissue handling is a second major issue. Minimal incision surgery should be used with great caution for knee replacements since the skin is much less forgiving than in hip replacements. A midline skin incision should be utilised when possible. When multiple incisions are present it is usually advisable to use the lateral most incision through which it is feasible to perform a knee replacement. In rare cases, a soft tissue expander may be used pre-operatively for thin, adherent skin.

Peri-operative steps that can be taken include delaying CPM in high risk wounds, and using a wound vac system in obese or other high risk wounds to minimise persistent drainage. Furthermore, anticoagulation should be used judiciously to avoid prolonged drainage. The final step in salvaging the problem wound is early recognition and aggressive management of wound healing problems. Prolonged, serous drainage is the most common clinical scenario. Drainage that is increasing beyond 5–7 days frequently requires evacuation, irrigation, debridement, and liner exchange. Early aspiration can decompress a hematoma and also rule out infection.

Surface replacement of the hip was established in the 1970's as a bone preserving alternative to total hip replacement. However, problems with femoral neck fracture, osteolysis, and component loosening led to early failures and an abandonment of the procedure.

The modern generation of hip resurfacing, however, has improved upon past results with new implant designs and materials. Better surgical guides and a short femoral stem allows for more accurate placement of the implants. A metal-on-metal articulation creates a larger diameter bearing and avoids polyethylene wear debris. Also paramount in the recent successes of surface replacement are refinements in surgical techniques, leading to more accurate component positioning, avoidance of neck notching, and an appreciation of the femoral head blood supply. The mid-term results of these newer hip resurfacing devices, coupled with appropriate patient selection and good surgical technique, have been encouraging.

Although more recently surface replacement has come under fire because of the metal-on-metal articulation, the Australian National Joint Registry finds that a certain group of patients has greater survivorship with resurfacing than with total hip replacement. Therefore, the presenter feels that surface replacement arthroplasty is still a viable option in this subgroup of patients. Additionally, the benefits of surface replacement include the preservation of bone, a lower dislocation rate, and potentially a higher activity level.

Computer navigation is an attractive tool for use in total knee arthroplasty (TKA), as it is well known that alignment is important for the proper function of a total knee replacement. Malalignment of the prosthetic joint can lead to abnormal kinematics, unbalanced soft tissues, and early loosening. Although there are no long term studies proving the clinical benefits of computer navigation in TKA, studies have shown that varus alignment of the tibial component is a risk factor for early loosening.

A handheld, accelerometer-based navigation unit for use in total knee replacement has recently become available to assist the surgeon in making the proximal tibial and distal femoral cuts. Studies have shown the accuracy to be comparable to large, console-based navigation units. Additionally, accuracy of cuts is superior to the use of traditional alignment guides, improving the percentage of cuts within 2 degrees of the desired alignment.

Because the registration is based on the mechanical axis of the knee, anatomic variables such as femoral neck-shaft angle, femoral length, and presence of a tibial bow do not affect the results. The handheld aspect of this navigation unit allows its use without additional incisions or array attachment. Furthermore, the learning curve and usage time is minimal, supporting its use in primary TKA.

Flexion contractures are a common finding in an end-stage arthritic knee, occurring in up to 60% of patients undergoing total knee arthroplasty. Fixed flexion deformities may result from posterior capsular scarring, osteophyte formation, and bony impingement. It is essential to correct this deformity at the time of total knee arthroplasty, as a residual flexion contracture will result in joint overload and abnormal gait mechanics. This may translate to a slower walking velocity, shorter stride length, and pain.

This presentation will discuss a systematic way of dealing with flexion contractures to ensure that the total knee arthroplasty will achieve full extension. The surgical technique for treating fixed flexion deformity about the knee includes release of the posterior cruciate ligament, posterior capsular release, adequate distal femoral bone resection, and removal of osteophytes.

Postoperatively, attention must be divided between obtaining maximal flexion and full extension. Should a flexion contracture be noted upon the postoperative visit, additional measures should be taken to address it.

Metal-on-metal hip arthroplasty has fallen out of favor because of complications arising from the articulation, namely metal sensitivity and accelerated wear. These complications can lead to early/mid-term failures from pain, osteolysis, implant loosening, and pseudotumor formation.

However, it has become clearer that MOM total hip arthroplasty behaves differently from MOM hip resurfacing, due to the additional junctions present in the total hip arthroplasty setting. Garbuz et al have demonstrated in a randomised controlled trial that MOM THA has significantly higher metal ion levels than MOM hip resurfacing. Clinical results of a MOM THA compared with a MOM HR using the same articulation also demonstrate significantly poorer results with the THA.

Newer literature has also shown that corrosion occurs at the taper junction of a THA due to the dissimilar metals. These corrosion products are likely what are causing a higher incidence of adverse local tissue reactions. Because a hip resurfacing implant is a monoblock ball, there is no taper junction of dissimilar metals that has the potential for corrosion.

National registry studies have also demonstrated a difference in the survival curves of MOM THA vs. hip resurfacing. MOM HR, in select patient groups, has a lower revision rate at 10 years than traditional metal-on-poly THA. Thus, to eliminate MOM hip resurfacing as a treatment option is akin to “throwing the baby out with the bathwater”, which the presenter deeply opposes.

Computer navigation is an attractive tool for use in total knee arthroplasty (TKA), as it is well known that alignment can affect clinical results. Malalignment of the prosthetic joint can lead to abnormal kinematics, unbalanced soft-tissue, and early loosening. Although there are no long term studies proving the clinical benefits of computer navigation in TKA, studies have shown that varus alignment of the tibial component is a risk factor for early loosening.

A handheld, accerelerometer based navigation unit for use in total knee replacement has recently become available to assist the proximal tibial and distal femoral cuts. Studies have shown the accuracy to be comparable to large, console-based navigation units. Additionally, accuracy of cuts is superior to the use of traditional alignment guides, improving the percentage of cuts within 2 degrees of the desired alignment.

Because the registration is based on the mechanical axis of the knee, anatomic variables such as femoral neck-shaft angle, femoral length, and presence of a tibial bow do not affect the results.

The handheld aspect of this navigation unit allows its use without additional incisions or array attachment. Furthermore, the learning curve and usage time is minimal, supporting its use in primary TKA.

Introduction:

A surgical hip dislocation provides circumferential access to the femoral head and is essential in the treatment pediatric and adult hip disease. Iatrogenic injury to the femoral head blood supply during a surgical may result in the osteonecrosis of the femoral head. In order to reduce vessel injury and incidence of AVN, the Greater Trochanteric Osteotomy (GTO) was developed and popularized by Ganz. The downside of this approach is the increased morbidity associated with the GTO including non-union in 8% and painful hardware requiring removal in 20% of patients. (reference) Recent studies performed at our institution have mapped the extra-osseous course of the medial femoral circumflex artery and provide surgical guidelines for a vessel preserving posterolateral approach. In this cadaveric model using Gadolinium enhanced MRI, we investigate whether standardized alterations in the postero-lateral surgical approach may reliably preserve femoral head vascularity during a posterior surgical hip dislocation

Background

Post-market surveillance is necessary to ensure the safety and efficacy of newly introduced technologies and implants. The Birmingham Hip Resurfacing (Smith and Nephew, Inc., Memphis, TN) was the first hip resurfacing implant approved for use by the US FDA in May 2006. A prospective, multi-center postmarket approval study has been in progress to assess safety and efficacy of this implant.