Introduction

A staging system has been developed to revise the 1994 ARCO classification for ONFH. The final consensus resulted in the following 4-staged system: stage I—X-ray is normal, but either magnetic resonance imaging or bone scan is positive; stage II—X-ray is abnormal (subtle signs of osteosclerosis, focal osteoporosis, or cystic change in the femoral head) but without any evidence of subchondral fracture, fracture in the necrotic portion, or flattening of the femoral head; stage III—fracture in the subchondral or necrotic zone as seen on X-ray or computed tomography scans. This stage is further divided into stage IIIA (early, femoral head depression ≤2 mm) and stage IIIB (late, femoral head depression >2 mm); and stage IV—X-ray evidence of osteoarthritis with accompanying joint space narrowing, acetabular changes, and/or joint destruction. Radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans may all be involved in diagnosing ONFH; however, the optimal diagnostic modality remains unclear. The purpose of this study was to identify: 1) how ONFH is diagnosed at a single academic medical center, and 2) if CT is a necessary modality for diagnosing/staging OFNH.

Background

Revision total knee arthroplasty (rTKA) is a complex procedure with increased risk of blood loss and transfusions. The Musculoskeletal Infection Society has included D-dimer as a serology marker for peri-prosthetic infection. The study's intent is to understand the impact of preoperative D-dimer levels on blood loss and venous thromboembolism in revision TKA.

Background

Proper positioning of the acetabular component is critical for prevention of dislocation and excessive wear for total hip arthroplasty (THA) and hip resurfacing. Consideration of preoperative pelvic tilt (PT) may aid in acetabular component placement. The purpose of this study was to investigate how PT changes after hip resurfacing, via pre and post-operative radiographic analysis of anterior pelvic plane (APP), and whether radiographic analysis of the APP is a reproducible method for evaluating PT in resurfaced hips.

Background

Manually instrumented knee arthroplasty is associated with variability in implant and limb alignment and ligament balance. When malalignment, patellar maltracking, soft tissue impingement or ligament instability result, this can lead to decreased patient satisfaction and early failure. Robotic technology was introduced to improve surgical planning and execution. Haptic robotic-arm assisted total knee arthroplasty (TKA) leverages three-dimensional planning, optical navigation, dynamic intraoperative assessment of soft tissue laxity, and guided bone preparation utilizing a power saw constrained within haptic boundaries by the robotic arm. This technology became clinically available for TKA in 2016. We report our early experience with adoption of this technique.

Introduction

Metal-on-Metal (MoM) bearing surfaces were historically used for young patients undergoing total hip arthroplasty, and remain commonplace in modern hip resurfacing. In theory, it has been postulated that metal ions released from such implants may cross the placental barrier and cause harm to the fetus. In light of this potential risk, recommendations against the use of MoM components in women of child-bearing age have been advocated. The purpose of this systematic review was to evaluate: 1) the Metal-on-Metal bearing types and ion levels found; 2) the concentrations of metals in maternal circulation and the umbilical cord; and 3) the presence of abnormalities in the fetus

Introduction

With an ongoing increase in total knee arthroplasty (TKA) procedural volume, there is an increased demand to improve surgical techniques to achieve ideal outcomes. Considerations of how to improve post-operative outcomes have included preservation of the infrapatellar fat pad (IPFP). Although this structure is commonly resected during TKA procedures, there is inconsistency in the literature and among surgeons regarding whether resection or preservation of the IPFP should be achieved. Additionally, information about how surgical handling of the IPFP influences outcomes is variable. Therefore, the purpose of this systematic review was to evaluate the influence of IPFP resection and preservation on post-operative flexion, pain, Insall-Salvati Ratio (ISR), Knee Society Score (KSS), patellar tendon length (PTL), and satisfaction in primary TKA.

Introduction

Component position and overall limb alignment following total knee arthroplasty (TKA) have been shown to influence prosthetic survivorship and clinical outcomes. Robotic-assisted (RA) total knee arthroplasty has demonstrated improved accuracy to plan in cadaver studies compared to conventionally instrumented (manual) TKA, but less clinical evidence has been reported.

The objective of this study was to compare the three-dimensional accuracy to plan of RATKA with manual TKA for overall limb alignment and component position.

BACKGROUND

High-volume surgeons and hospital systems have been shown to deliver higher value care in several studies. However, no evidence-based volume thresholds for cost currently exist in total hip arthroplasty (THA). The objective of this study was to establish clinically meaningful volume thresholds based on cost for surgeons and hospitals performing THA. A secondary objective was to analyze the relative market share of THAs among the newly defined surgeon and hospital volume strata.

Introduction

While manual total knee arthroplasty (MTKA) procedures have demonstrated excellent clinical success, occasionally intraoperative damage to soft tissues can occur. Robotic-arm assisted technology is designed to constrain a sawblade in a haptic zone to help ensure that only the desired bone cuts are made. The objective of this cadaver study was to quantify the extent of soft tissue damage sustained during TKA through a robotic-arm assisted (RATKA) haptically guided approach and conventional MTKA approach.

Introduction

A careful evaluation of new technologies such as robotic-arm assisted total knee arthroplasty (RATKA) is important to understand the reduction in variability among users. While there is data reviewing the use of RATKA, the data is typically presented for experienced TKA surgeons. Therefore, the purpose of this cadaveric study was to compare the variability for several surgical factors between RATKA and manual TKA (MTKA) for surgeons undergoing orthopaedic fellowship training.

Introduction

Hip resurfacing arthroplasty (HRA) is an alternative to traditional total hip arthroplasty (THA) in young active patients. While comparative implant survival rates are well documented, there is a paucity of studies reporting the patient mortality rates associated with these procedures. The purpose of this study was to evaluate the mortality rates in patients age 55 years and younger who underwent HRA versus THA and to assess whether the type of operation was independently associated with mortality.

Multiple newer wound closure techniques have been recently developed with the goals being reducing closure time, enhancing cosmesis, and decreasing wound healing problems including infections. Among these techniques are the zipper-like closure, absorbable dermal staples, scaffold devices, and others. Each of these techniques propose certain advantages. Nevertheless, this comes at an added cost and careful weighing of the cost/benefit should be considered in an evidence-based manner, in order to guide future recommendations for using these techniques.

Despite the demonstrated success in revision total joint arthroplasties, the utilization of antibiotic-loaded bone cement in primary total joint arthroplasty remains controversial. Multiple studies have demonstrated several risks associated with the routine use of this technique including: allergic reactions, changing the mechanical properties of the cement, emergence of resistant bacterial strains, systemic toxicity, and the added cost. In addition, evidence shows a currently low rate of periprosthetic joint infections in primary total joint arthroplasty (around 1%) and the theoretical benefit of marginally reducing this rate by using antibiotic-cement may not necessarily justify the associated risks and the added cost. Moreover, most of the primary total hip and an increasing number of primary total knee arthroplasties are cementless, which further raises questions about the routine use of antibiotic-loaded bone cement in primary total joint arthroplasty.

Patients who have multiple sclerosis (MS) may be at increased risk of developing complications after total hip arthroplasty (THA). The purpose of this study was to compare: 1) implant survivorship; 2) functional outcomes; 3) complication rates; and 4) radiographic findings after THA between MS patients and a matched cohort.

A single institutional database was reviewed for patients who had a diagnosis of MS and underwent a THA. Thirty-four patients (41 hips) were matched to a 2:1 cohort who did not have MS using based on age, sex, body mass index (BMI), and Charlson/Deyo scores. This resulted in a matching cohort of 80 patients (82 hips). The available medical records were reviewed. Functional outcomes and complications were assessed. Postoperative radiographs were evaluated.

The matching cohort had higher all-cause survivorship at 4-years postoperatively (99 vs. 93%). There were 3 revisions in the MS cohort and 0 revisions in the matching cohort. The MS cohort had lower mHHS scores (66 vs.74 points, p<0.001), lower HOOS JR scores (79 vs. 88 points, p<0.01), required more physical therapy (5 vs. 3 weeks, p<0.01), and took longer to return to their baseline functional level (7 vs. 5 weeks, p<0.05). MS patients had higher rate of complications (6 vs. 1, p<0.05). Excluding revision cases, there was no additional radiographic evidence of progressive radiolucency, loosening, or subsidence.

We found that MS patients had lower implant survivorship, lower functional outcome scores, and increased complication rates. These findings may help orthopaedists to have a better knowledge of how MS patients do after THA.

While total knee arthroplasty has demonstrated clinical success, final bone cut and final component alignment can be critical for achieving a desired overall limb alignment. This cadaver study investigated whether robotic-arm assisted total knee arthroplasty (RATKA) allows for accurate bone cuts and component position to plan compared to manual technique. Six cadaveric specimens (12 knees) were prepared by an experienced user of manual total knee arthroplasty (MTKA), who was inexperienced in RATKA. For each cadaveric pair, a RATKA was prepared on the right leg and a MTKA was prepared on the left leg. Final bone cuts and final component position to plan were measured relative to fiducials, and mean and standard deviations were compared.

Measurements of final bone cut error for each cut show that RATKA had greater accuracy and precision to plan for femoral anterior internal/external (0.8±0.5° vs. 2.7±1.9°) and flexion/extension* (0.5±0.4° vs. 4.3±2.3°), anterior chamfer varus/valgus* (0.5±0.1° vs. 4.1±2.2°) and flexion/extension (0.3±0.2° vs. 1.9±1.0°), distal varus/valgus (0.5±0.3° vs. 2.5±1.6°) and flexion/extension (0.8±0.5° vs. 1.1±1.1°), posterior chamfer varus/valgus* (1.3±0.4° vs. 2.8±2.0°) and flexion/extension (0.8±0.5° vs. 1.4±1.6°), posterior internal/external* (1.1±0.6° vs. 2.8±1.6°) and flexion/extension (0.7±0.6° vs. 3.7±4.0°), and tibial varus/valgus* (0.6±0.3° vs. 1.3±0.7°) rotations, compared to MTKA, respectively, (where * indicates a significant difference between the two operative methods based on 2- Variances testing, with α at 0.05). Measurements of final component position error show that RATKA had greater accuracy and precision to plan for femoral varus/valgus* (0.6±0.3° vs. 3.0±1.4°), flexion/extension* (0.6±0.5° vs. 3.0±2.1°), internal/external (0.8±0.5° vs. 2.6±1.6°), and tibial varus/valgus (0.7±0.4° vs. 1.1±0.8°) than the MTKA control, respectively.

In general, RATKA demonstrated greater accuracy and precision of bone cuts and component placement to plan, compared to MTKA in this cadaveric study. For further confirmation, RATKA accuracy of component placement should be investigated in a clinical setting.

The prevalence of knee osteoarthritis (OA) in The United States is approximately 40 million cases, and this number is expected to rise to 60 million by the year 2020. Multiple non-operative treatment options are available for patients, including bracing. Braces can also be used for “pre-habitation” prior to total knee arthroplasty (TKA), after TKA, after traumatic sports injuries, and in neurologic patients. Although, the AAOS recommendations for brace use for treatment of knee osteoarthritis (OA) are “inconclusive”, recent studies have shown improved functional outcomes with the use of off-loader braces for the treatment of uni-compartmental knee OA. In addition, supplemental modalities such as transcutaneous electrical nerve stimulation (TENS) and neuromuscular electrical stimulation (NMES) have demonstrated improved subjective and functional outcomes. These off-loader braces and supplemental modalities are easy to use, may decrease pain, delay TKA, and improve clinical outcomes following surgery. In addition, they may decrease the use of other costly knee OA treatment options such as pain medications and intra-articular injections.

Heterotopic ossification (HO) is a relatively common complication of total hip arthroplasty (THA), but is rather rare after total knee arthroplasty (TKA). In both cases, it is usually asymptomatic and is most commonly identified as an incidental finding on post-operative radiographs. However, in severe cases it can result in decreased range of motion and pain. There are several risk factors that have been shown to be associated with development of HO. These include male gender, ceramic-on-ceramic bearings, prior stroke, and hypertrophic osteoarthritis.

Heterotopic ossification can be treated with physical therapy during the maturation phase (12 to 24 weeks), but surgical intervention is required if the stiffness persists. All heterotopic bone should be excised with careful attention to neurovascular structures. Patients should begin prophylaxis following HO excision and prior to any subsequent surgeries. Heterotopic ossification prophylaxis consists of NSAIDs, radiotherapy, or a combination of both modalities. These therapies are not without complications, therefore, routine administration of prophylaxis for all patients is not indicated. Several new pathways of inhibiting extra-skeletal bone formation in HO are under investigation (retinoid acid receptor agonists, apyrase, and LDN-193189). Future studies should focus on identification of patients at risk for HO as well as better therapeutic options with less side effects.

Introduction

There is a paucity of studies analyzing the rates of revision total knee arthroplasty in diabetic patients stratified by glycated hemoglobin levels. The purpose of this study was to: 1) determine the incidence of revision TKA; 2) correlate the percent of glycated hemoglobin with incidence of revision; and 3) determine the cause of revision in diabetic patients stratified by glycated hemoglobin level.

Background

Total knee arthroplasty (TKA) is a routine, cost-effective treatment for end-stage arthritis. While the evidence for good-to-excellent patient-reported outcomes and objective clinical data is present, approximately 20% of patients continue to be dissatisfied with results of their surgery. Dissatisfaction is strongly correlated with unmet patient expectations, and these patients may experience a higher cost of care due to recurring office and emergency visits. Therefore, this survey asked a large group of United States (U.S) and international surgeons to prioritize areas of opportunity in primary TKA. Specifically, we compared surgeon responses regarding: 1) the top 5 areas needing improvement; which were stratified by: 2) surgeons' years of experience; and 3) surgical case volume.

INTRODUCTION

Femoral stem impingement can damage an acetabular liner, create polyethylene wear, and potentially lead to dislocation. To avoid component-to-component impingement, many surgeons aim to align acetabular cups based on the “Safe Zone” proposed by Lewinnek. However, a recent study indicates that the historical target values for cup inclination and anteversion defined by Lewinnek et al. may be useful but should not be considered a safe zone. The purpose of this study was to determine the effect of altering femoral head size on hip range-of-motion (ROM) to impingement.

Background

Sequentially annealed, highly crosslinked polyethylene (HXLPE) has been used clinically in total knee arthroplasty (TKA) for over a decade[1]. However, little is known about the reasons for HXLPE revision, its surface damage mechanisms, or its in vivo oxidative stability relative to conventional polyethylene. We asked whether retrieved sequentially annealed HLXPE tibial inserts exhibited: (1) similar reasons for revision; (2) enhanced resistance to surface damage; and (3) enhanced oxidative stability, when compared with tibial inserts fabricated from conventional gamma inert sterilized polyethylene (control).

Introduction

During revision surgery with a well-fixed stem, a titanium sleeve can be used in conjunction with a ceramic head to achieve better stress distribution across the taper surface. Previous studies have observed that the use of a ceramic head can mitigate the extent of corrosion damage at the taper. Moreover, in vitro testing suggests that corrosion is not a concern in sleeved ceramic heads [1]; however, little is known about the in vivo fretting corrosion of the sleeves. The purpose of this study was to investigate fretting corrosion in sleeved ceramic heads.

Osteonecrosis (ON) is a debilitating condition that can progress to severe arthritis of the hip. While its exact pathogenesis remains poorly understood, ON is known to be associated with risk factors such as corticosteroid use, alcoholism, and autoimmune disease. Initial radiographic evaluation can reveal sclerotic and cystic changes in the femoral head, which are usually the first clues in diagnosis. Despite these indicators, plain radiographs generally are not sufficient for diagnosis, therefore requiring subsequent magnetic resonance imaging (MRI) studies. Moreover, performing an appropriate assessment of these imaging modalities can help guide the course of treatment. Treatment options are aimed at slowing or stopping the onset of femoral head collapse and include non-operative management, joint preservation procedures, and total joint arthroplasty. Patients at risk of developing ON may benefit from early diagnosis because the characteristic small or medium-sized pre-collapse lesions that are associated with this stage can often be treated with a non-operative or joint preservation approach. However, patients typically present with advanced disease progression and sometimes an unsalvageable joint, thereby necessitating more invasive operative intervention. Surgical modalities include the use of osteotomy, core decompression, vascular grafts, bone graft substitutes, resurfacing, and finally, total hip arthroplasty. Additionally, reports from the past several decades describe improved outcomes and survivorship of these surgical treatment options. Therefore, our purpose is to highlight recent evidence regarding the management of ON with emphasis on the various forms of operative intervention as well as their outcomes.

Knee osteoarthritis (OA) is a progressive and debilitating condition that is estimated to account for over 80% of the osteoarthritis burden. In cases of end-stage osteoarthritis, surgical intervention is the desired option, however, less severe cases may warrant the use of nonoperative modalities. Knee braces are becoming increasingly popular as an adjunct to the standard treatment and have shown promising results in reducing pain, improving function, and mitigating disease progression. Moreover, bracing has the added benefit of being able to include other noninvasive modalities as a means to augment recovery and delay the need for surgery. Prior studies have demonstrated that the medial compartment of the knee joint sustains 62% of loading forces during the stance phase of regular gait, whereas the lateral compartment receives the remaining 38%. It is hypothesised that this distribution of loading forces is why the medial joint compartment is more frequently damaged relative to the lateral compartment. Reduction of these stresses can be accomplished by the use of medial compartment unloader braces, which incorporate distraction forces and rotation with the purpose of increasing the medial joint space and providing pain relief. These devices have the potential to correct the characteristic gait changes associated with knee OA and enhance patients' functional status. Therefore, our main purpose is to assess the efficacy of the various types of knee braces used for the treatment of osteoarthritic knee pain as well as offer perspective regarding the use of knee braces at our institution.

Recent advancements in biomaterial technology have created novel options for acetabular fixation in primary total hip arthroplasty (THA). For example, cementless acetabular fixation has become the preferred option, however, there is continued debate concerning whether long-term survivorship is comparable to that of cemented component fixation. Many doubts previously associated with early cementless designs have been addressed with newer features such as improved locking mechanisms, enhanced congruity between the acetabular liner and the shell, and the inclusion of highly cross-linked ultra-high molecular weight polyethylene (UHMWPE). Additionally, there has been increased utilization of new porous metals, titanium mesh, and hydroxyapatite (HA) coated implants. However, several retrieval studies have indicated that porous-coated cementless acetabular components can exhibit poor bony ingrowth. Many surgeons in Europe favor cemented fixation, where registry data is favorable for this interface. A surgeon's decision to use a cemented or cementless acetabular component is typically dependent on factors such as patient bone stock, surgical training, and experience. With the frequency of THAs expected to increase, it is particularly important for orthopaedic surgeons to be familiar with appropriate preoperative planning and component selection in an effort to achieve optimal outcomes. Therefore, this talk will outline and describe the options currently available for cementless and cemented acetabular fixation in primary total hip arthroplasty.

Post-surgical wound infections following total hip or knee arthroplasties can be a potentially catastrophic complication for the patient. Currently, several preventative measures exist to help combat this complication. One such method is skin disinfection with preadmission cutaneous chlorhexidine preparation. Although efficacious in reducing surgical site infections during total joint arthroplasty, orthopaedists should be aware of discrepancies between hip and knee arthroplasty. For example, Kapadia et al. performed a prospective study which evaluated the use of preadmission cutaneous chlorhexidine preparation on the reduction of surgical site infections following total hip arthroplasty; they found that there was a 3-fold higher relative risk of developing infection in patients who did not receive the chlorhexidine preparation as compared to those who did. In a similar study performed for total knee arthroplasty, the same authors founds a 6-fold higher relative risk of developing infection, which equated to double the risk as compared to total hip arthroplasty. In a study by Lewis et al. regarding timing to diagnosis of surgical site infections in post-hip and knee arthroplasties, the authors found a longer median time to diagnosis post-knee arthroplasty as compared to hip arthroplasty (25 vs. 42 days, p= <0.001). These finding suggest that orthopaedists should recognise that “A knee is not a hip” with regards to surgical site infections and should be aware of the discrepancies that exist between the two.

Knee osteoarthritis (OA) is a debilitating and progressive condition that accounts for over 80% of the total osteoarthritis burden. Surgical intervention is the suitable option in end-stage osteoarthritis, however, in cases of less severe disease, it may be warranted to use non-operative methods. Knee braces have recently become a popular option as an addition to conventional treatment, and have displayed good results in improving function, reducing pain, and attenuating disease progression. Furthermore, other non-invasive modalities can be supplemented to bracing as a means to improve recovery and delay the need for surgery. Studies have indicated that the medial compartment of the knee sustains 62% of loading forces during the stance phase of regular gait, meanwhile the lateral compartment receives the remaining 38%. It is postulated that this distribution of knee loading forces is the reason why the medial compartment is more frequently deteriorated as compared to the lateral joint compartment. The use of medial compartment unloader braces can reduce these stresses by the means of distraction and rotation of the knee joint with the goal of increasing the medial joint space and producing pain relief. Knee bracing has the capability to enhance patients’ functional status, and even correct the gait changes associated with knee OA. Therefore, our goal is to assess: 1) the use of knee braces at our institution, and 2) the effectiveness of the various types of knee braces in treating OA associated knee pain.

Introduction

Thermally treated 1st generation highly crosslinked polyethylenes (HXLPE) have demonstrated reduced penetration and osteolysis rates, however, concerns still remain with respect to oxidative stability and mechanical properties of these materials. To address these concerns, manufacturers have introduced the use of antioxidants to quench free radicals while maintaining the mechanical properties of the HXLPE. Two common antioxidants are α-tocopherol (Vitamin-E) and pentaerythritol tetrakis (PBHP). These may be either mixed prior to consolidation, or diffused throughout the polymer after consolidation and irradiation. In vitrostudies have shown that these materials are oxidatively stable and have improved mechanical properties compared to 1st generation HXLPEs; however, few studies have investigated the in vivo performance of anti-oxidant stabilized HXLPE. The purpose of this study was to investigate the revision reasons, oxidation, and mechanical properties of retrieved short-term anti-oxidant HXLPE.

Introduction

Highly crosslinked polyethylene (HXLPE) was clinically introduced approximately a decade and a half ago to reduce polyethylene wear rates and subsequent osteolysis. Clinical and radiographic studies have repeatedly shown increased wear resistance, however concerns of rim oxidation and fatigue fracture remain. Although short to intermediate term retrieval studies of these materials are available, the long-term behavior of these materials remains unclear.

Introduction

Previous studies of retrieved CoCr alloy femoral heads have identified imprinting of the stem taper surface features onto the interior head bore, leading researchers to hypothesize that stem taper microgrooves may influence taper corrosion. However, little is known about the role of stem taper surface morphology on the magnitude of in vivo corrosion damage. We designed a matched cohort retrieval study to examine this issue.

Introduction

Recent implant design trends have renewed concerns regarding metal wear debris release from modular connections in THA. Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Comparatively little is known about head-neck taper corrosion with ceramic femoral heads or about how taper angle clearance influences taper corrosion. This study addressed the following research questions: 1) Could ceramic heads mitigate electrochemical processes of taper corrosion compared to CoCr heads? 2) Which factors influence stem taper corrosion with ceramic heads? 3) What is the influence of taper angle clearance on taper corrosion in THA?

There are many reasons that the surgically inclined orthopaedic surgeon should be responsible for the medical management of osteoarthritis of the knee. These include: 1) The nonoperative treatment of OA is often highly effective for all stages of the disease; 2) A nonoperative treatment program is the best preparation for a successful surgical outcome; and 3) Patients appreciate a surgeon's interest in their overall care and are likely to return if surgery is needed; 4) Medicare and many insurance companies are refusing to pay for a TJA until many months of conservative management has been administered. There are many potential causes of pain in an arthritic knee. These include intra-articular (e.g. degenerative meniscal tears, loose bodies, synovitis) and extra-articular (tendonitis, e.g. ilio-tibial band syndrome, bursitis, muscle overload syndromes and referred pain) sites. The potential sources of pain in an arthritic knee produce a wide range of symptoms that are not necessarily correlated with objective measurements (e.g. x-rays, MRI). Moreover, the natural history of an arthritic knee is unpredictable and variable.

The treatment of the young, arthritic knee patient of all stages requires a systematic and consistent non-surgical approach. This approach includes the use of: 1) analgesics/anti-inflammatory agents; 2) activity modification; 3) alternative therapies; 4) exercise; 5) injections/lavage. The response to each form of non-surgical treatment is unpredictable at each stage (Kellgren 1–4) of OA. The placebo effect of each from of treatment, including the physician-patient interaction, is 50–60% in patients with mild-moderate OA.

The components of a nonoperative treatment program include: 1) Education-emphasising the importance of the patient taking charge of his/her care; 2) Appropriate activity/life style modifications-emphasising the importance of remaining active while avoiding activities that aggravate symptoms (e.g. running to biking); 3) medications-oral, topical, intra-articular; 4) Physical therapy. There are extensive data to support each of these interventions. The AAOS has issued guidelines highlighted the literature based effectiveness of conservative interventions.

Osteoarthritis (OA) is a highly prevalent disease that has a debilitating role in every day function and activity. In 2002, the indirect cost of OA was 5 billion dollars, secondary to absenteeism and loss of productivity. There are multiple management options available for OA, with surgery usually being a last resort. Total knee arthroplasty (TKA) provides a long-lasting treatment option with excellent results. However, a high proportion of patients still express dissatisfaction following surgery, possibly due to a combination of pain, continued limitation of function, and high expectations. The use of bracing provides a non-operative treatment option as well as a useful therapy adjunct in patients who undergo TKA. Bracing may aid in rehabilitation prior to TKA as well as postoperatively, and it also plays a beneficial role in problematic situations, such as patients who have undergone revision surgery or who have extensor mechanism problems. They are thought to aid in gait ‘retraining’, quadriceps muscle strengthening, improving joint alignment, and increasing stability of the joint. Although the American Academy of Orthopedic Surgeons remains inconclusive on the role of bracing, multiple studies have highlighted that they may be of benefit. The use of valgus bracing has been shown to provide short-term treatment for activity, bracing for uni-compartmental OA has shown an improvement in outcome measures, and the use of an unloader brace has led to improved general physical health and function outcomes, as measured by the SF-12 and WOMAC, respectively.

Knee stiffness is a well-recognised postoperative problem that has been reported to occur in 6% to 15% of all patients who undergo total knee arthroplasty (TKA), and there are multiple preoperative, intraoperative, and postoperative risk factors that may predispose patients to postTKA knee stiffness. Preoperative risk factors include poor baseline range of motion (ROM), obesity, and a history of previous knee surgery and/or trauma. Potential intraoperative risk factors for having a stiff knee are malalignment, gap imbalance, and under-resection of patella. Possible postoperative risk factors include heterotopic ossification, pain, poor patient motivation, and poor physical therapy compliance. Three commonly used adjuvant treatments for this condition are custom knee devices, Botox, and ASTYM. These treatment modalities are most effective when used within 6 weeks after surgery. Multiple case series have reported that CKD can improve range of motion while maximising patient-reported functional outcomes. Botox can improve range of motion by paralyzing the muscle where the contracture is located. ASTYM therapy has recently been reported to resolve muscle contractures by effectively stimulating tissue turnover, scar tissue resorption, and regeneration of the normal soft tissue structure. When these adjuvant therapies fail, manipulation under anesthesia has been reported to be efficacious in restoring some of the original ROM. If this fails, there are surgical treatment options such as arthroscopic debridement, surgical release, revision TKA, or peroneal nerve release.

Summary Statement

This study assesses oxidation, mechanical behavior and revision reasons of 2^nd generation HXLPE used in total hip and knee arthroplasty. While oxidation was low for both X3 and E1 HXLPEs, oxidative regional variations were detected in the sequentially annealed cohort.

Summary Statement

Fretting and corrosion has been identified as a clinical problem in modular metal-on-metal THA, but remains poorly understood in modern THA devices with polyethylene bearings. This study investigates taper damage and if this damage is associated with polyethylene wear.

Traditionally, arthritis is a disease which generally affects the elderly population. However, the incidence in young patients is well described and is increasing with the ever-growing obese population. Currently, the non-surgical treatment of osteoarthritis consists of corticosteroid injections, hyaluronic acid injections, weight loss, physical therapy, bracing, orthotics, narcotics, and non-steroidal anti-inflammatory drugs (NSAIDS).

Oral medications (NSAIDS, tramadol, and opioids) can provide effective pain relief. Improvement with NSAIDs has been reported to be 20% relative to baseline, with better improvements seen with selective cox-2 inhibitors, which also have reduced gastrointestinal and renal toxicity. Additionally, the recent AAOS guidelines strongly recommend using NSAIDs or tramadol for pain relief. Although narcotics are effective analgesics, their use in young arthritic patients can potentially predispose individuals to future opioid dependency, and thus should be used sparingly.

The primary purpose of physical therapy is to improve range of motion, strengthen muscles, and improve proprioception. Currently, the AAOS strongly recommends that patients undergo self-management programs, strengthening, low-impact aerobic exercises, and neuromuscular education. Similarly, they moderately recommended that patients with a BMI ≥ 25 undergo weight loss for symptomatic arthritis. Bracing options consist of the following: off-loader braces and transcutaneous nerve stimulation braces. These work to either off-load pressure in the knee or to scramble small nerve pain sensation, respectively.

Corticosteroid injections are used to minimise pain and reduce inflammation in the joint associated with arthritis. However, their long-term repetitive use in young patients is not recommended, and current AAOS guidelines are inconclusive on their effectiveness. Additionally, the AAOS guidelines strongly recommend against the use of acupuncture, glucosamine/chondroitin, and hyaluronic acid injections.

Introduction

Periprosthetic infection following lower extremity total joint arthroplasty often requires multiple surgical procedures and imposes a marked economic burden on the patient and hospital. The purpose of this study was to evaluate the incidence of surgical site infections in total joint arthroplasty patients who used an advance at-home pre-admission cutaneous preparation protocol and to compare these results to a cohort of patients who underwent standard in-hospital peri-operative preparation only.

Introduction:

First generation highly crosslinked polyethylenes (HXPLEs) have proven successful in lowering both penetration and osteolysis rates. However, 1^st generation annealing and remelting thermal stabilization have been associated with in vivo oxidation or reduced mechanical properties. Thus, 2^nd generation HXLPEs were developed to improve oxidative stability while still maintaining material properties. Little is known about the in vivo clinical failure modes of these 2^nd generation HLXPEs.

The purpose of this study was to assess the revision reasons, wear, oxidative stability, and mechanical behavior of retrieved sequentially annealed Vitamin E diffused HXLPE in THA and TKA.

Background:

Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Less is known about head-neck taper corrosion with ceramic femoral heads.

Introduction:

Degradation of modular head-neck tapers was raised as a concern in the 1990s (Gilbert 1993). The incidence of fretting and corrosion among modern, metal-on-polyethylene and ceramic-on-polyethylene THA systems with 36+ mm femoral heads remains poorly understood. Additionally, it is unknown whether metal debris from modular tapers could increase wear rates of highly crosslinked PE (HXLPE) liners.

The purpose of this study was to characterize the severity of fretting and corrosion at head-neck modular interfaces in retrieved conventional and HXLPE THA systems and its effect on penetration rates.

Common reasons for higher-than-average cost for a total hip arthroplasty are prolonged patient hospitalisation, which can be caused by among other factors, bleeding complications. The incidence of perioperative anemia has direct costs (blood transfusions), but also numerous indirect costs such as longer hospital stays, poor performance in physical therapy, and the potential for blood-borne infection. The incidence of pre-operative anemia in patients undergoing total hip arthroplasty has been reported to be as high as 44%, while total peri-operative blood loss for total hip arthroplasty may average between 750 and 1,000 mL. Anemia negatively impacts length of stay, patient function during rehabilitation, and patient mortality. Transfusions carry well known risks, including infection and fatal anaphylaxis, which are important factors considering that the transfusion rate has been reported to be as high as 45% and that transfused patients receive, on average, two units of blood.

Methods that have been described in the literature include pre-treatment with erythropoietin, pre-operative hemodilution with intra-operative blood salvage, surgical techniques such as gentle soft tissue handling and meticulous hemostasis, bipolar sealers, intravascular occlusion, hemostatic agents, and early removal of drains.

Pharmacologic approaches include treatment with erythropoietin, iron and folate. Randomised trials have demonstrated reduction in the risk for transfusion in patients treated with erythropoietin. Several studies have established a once-weekly dosing schedule of 40,000 international units (300–600 IU/kg) to be effective, and synergism has been observed in patients treated in combination with iron (ferrous sulfate, 325 mg three times a day). Patients with hemoglobin values between 10 and 14 g/dL are most likely to benefit. Intra-operatively, antifibrinolytics such as tranexamic acid (10 mg/kg) given as a single dose pre-operatively has been shown to decrease blood loss and the transfusion rate. Hypotensive anesthesia also effectively decreases blood loss without impairing renal function, but is technically demanding. Post-operatively, re-infusion drains may reduce the need for transfusions in total hip and total knee arthroplasty, but cannot be used in cases of infection or malignancy.

By minimising peri-operative bleeding and bleeding complications through pre-operative optimisation, intra-operative surgical techniques that minimise blood loss, and post-operative care, patient disposition can be streamlined and delays for patient discharge can be avoided.

Osteonecrosis is a pathologic bone condition caused by a disruption in the osseous circulation and impairment of normal cellular function which ultimately leads to bone infarction, osteocyte death, and joint degeneration. The incidence of osteonecrosis in the general population has been reported to be approximately 3 per 100,000 people. Up to 20,000 new cases are diagnosed each year and this condition is the indication for surgery in approximately 10% of all total hip arthroplasties performed in the United States. The hip is the most common joint affected, with approximately 75% of cases occurring in this joint, although multifocal osteonecrosis (defined as involvement of more than 3 joints) can also occur. Other commonly observed locations for osteonecrotic lesions include the knee, shoulder, wrist, and ankle.

Joint preserving procedures may be performed for early stages without evidence of collapse, while intermediate lesions (e.g. femoral head collapse < 2 mm) may be candidates for joint preserving procedures such as bone grafting and rotational or proximal femoral varus osteotomies. However, total hip arthroplasty is usually required in advanced cases where there are large lesions, deformation of the femoral head, or acetabular involvement.

Osteonecrosis has been traditionally associated with poor outcomes following total hip arthroplasty. However, recent studies using newer implant designs and surgical techniques have demonstrated outcomes comparable to the general total hip arthroplasty population. Johansson and colleagues, in a systematic reviewed of the literature, observed a decrease in the revision rate from 17% to 3% for arthroplasties performed later than 1990. The clinical outcomes were also comparable between patients who had osteoarthritis and those who had osteonecrosis.

The young age at which these patients often present makes bearing surface choice challenging. Bearings that have low liner wear rates, such as ceramic bearings, had concerns with implant durability following reports of chipping and fracture of the ceramic. However, recent studies evaluating ceramic bearings in young patients with osteonecrosis have demonstrated that newer third and fourth generation ceramics have solved many of these issues. Byun et al. evaluated the clinical outcomes of ceramic bearings in patients younger than 30 years who had osteonecrosis and observed that at six year follow-up, none of the bearings had failed and that 95% of patients were able to continue with their prior occupation. Similar results at even longer follow-up periods were reported by Kim and colleagues who observed no failures in 93 ceramic hips at a mean follow-up of 11 years.

Polyethylene wear continues to be a concern for these younger, more active patients. Early studies with non-highly cross linked polyethylene demonstrated high wear rates in these patients. Although newer polyethylene designs have become available which have demonstrated substantially lower wear than the traditional ultra high molecular weight polyethylene cups of the recent past, further studies are needed with these newer polyethylene bearings in the osteonecrosis population.

The goal of treatment for femoral head osteonecrosis remains early diagnosis and joint preservation. For patients who present with femoral head collapse or acetabular involvement, total hip arthroplasty often is the only treatment option left. Although clinical outcomes for these patients were initially poor in earlier reports, the advent of modern cementless arthroplasty components, refined surgical techniques, and newer bearing designs have greatly improved the outcomes of this procedure.

Introduction

Sequentially annealed highly crosslinked polyethylenes (HXLPEs) were introduced in total knee replacement (TKR) starting in 2005 to reduce wear and particle-induced osteolysis. Few studies have reported on the clinical performance of HXLPE knees. In this study, we hypothesized that due to the reduced free radicals, sequentially annealed HXLPE would have lower oxidation levels than gamma inert-sterilized controls.

Introduction

Wear debris generation in metal-on-metal (MOM) total hip arthroplasty (THA) has emerged as a compelling issue. In the UK, clinically significant fretting corrosion was reported at head-taper junctions of MOM hip prostheses from a single manufacturer (Langton 2011). This study characterizes the prevalence of fretting and corrosion at various modular interfaces in retrieved MOM THA systems used in the United States.

Introduction

The purpose of this multicenter study was to assess the oxidative stability, mechanical behavior, wear and reasons for revision of 2nd generation sequentially annealed HXLPE, X3, and compare it to 1^st generation XLPE, Crossfire. We hypothesized that X3 would exhibit similar wear rates but lower oxidation than Crossfire.

Summary

Single use instrumentation had a significant reduction on OR Turnover time and instrument setup/clean up time compared to traditional instrumentation.

Hip and knee wear simulators have been used by implant manufacturers and researchers for many years as a performance predictor and comparator for hip and knee implants. The clinical accuracy of these simulators in predicting wear depends heavily on the type of simulator as well as the methodology used. The joint lubricant used in the simulators is one crucial aspect that has been well studied in hip simulators. This study will compare the wear performance of a modern total knee replacement system using two commonly used simulator lubricants at various dilutions (Alpha Calf Serum and Bovine Calf Serum, Hyclone Labs). The Triathlon knee implant system (Stryker Orthopaedics) was used along with a six station knee wear simulator from MTS Systems to determine the effect of lubricant type and dilution.

Wear rates were found to be dependent on the type and dilution of the lubricant. At 0g/L protein concentration (100% water) wear rates were 4.8mm3/million cycles (mc). With the introduction of Bovine serum, wear rates increase to a peak of 24mm3/mc at 5g/L of concentration. Increased concentration of Bovine serum resulted in a decrease of wear rates. Wear rates for Alpha serum peaked at 28mm3/mc at 20g/L concentration with decreased wear rates at higher concentrations.

Knee implant wear performance is often characterized by wear simulation. As has been previously shown for hip simulations, this study shows the importance of choosing the correct lubricant type and dilution to correctly simulate wear performance. While this study cannot correlate any of the lubricants to the synovial fluid present in vivo, this study shows that 20g/L of Alpha serum produces the highest wear rates and should be used to determine worst case wear rates in the wear performance characterization of knee implants.

Introduction: Osteonecrosis is a devastating disease which can affect multiple joints including the distal radius. Although there are a number of studies that have reported the clinical outcomes of patients treated for osteonecrosis of the hip, knee, shoulder, and other locations, there are no known studies that have evaluated the outcome of patients who have this disease in the distal radius. The purpose of this study was to assess the characteristics of atraumatic, symptomatic osteonecrosis of the distal radius. In addition, based on reports that have shown the safe and effective use of core decompressions to treat early stages of osteonecrosis in other joints, we assessed whether this treatment modality also would provide pain relief and delay progression of the disease in the distal radius.

Methods: A review of 434 osteonecrosis patient records from the past 7 years in our prospectively collected database identified 4 patients (6 wrists) who had the disease in the distal radius. Two of these patients also had the disease in the ulna. All 4 patients were women, and their mean age was 46 years (range, 37 to 52 years). Clinical and radiographic outcomes were assessed at a mean of 39 months (range, 12 to 84) following treatment with core decompression. The clinical evaluations were conducted using the Michigan Hand Outcomes Questionnaire (MHQ). The reported pre-operative MHQ component scores for function, completion of everyday activities, pain, completion of work activities, overall appearance of the hands, and patient satisfaction were compared to the results of the MHQ at final follow-up. Radiographic success of the core decompressions was based on whether there was any progression in the stage of the disease.

Results: The most common risk factor for this cohort of patients was corticosteroids with 3 of the 4 patients having reported prior use. Other risk factors included alcohol consumption on a regular basis (n = 2), tobacco abuse (n = 2), blood dyscrasia (n = 2), and systemic lupus erythematosus (n = 1). Additionally, all 4 patients had multifocal osteonecrosis (affecting at least four separate anatomic sites. Overall, the patients reported a mean improvement in MHQ score (from 65% to 84%). Stratified by category, satisfaction improved from 64% to 88%, overall hand function increased from 64% to 81%, and pain was reduced from 60% to 25%, for pre- and post-operative values, respectively. One patient (2 wrists) required additional core decompressions in each wrist at one year following surgery but reported sustained improvement in her MHQ for both wrists at two years following her second core decompressions. There were no complications associated with the core decompressions, and there was no radiographic progression in the stage of the disease in any of the cases.

Discussion: Osteonecrosis of the distal radius is rarely found in patients with this disease (< 1%). It can be found in patients with osteonecrosis of other joints who have a symptomatic wrist and may have more than one risk factor. It can be readily diagnosed with x-rays and/or MRI. The results of the present study suggest that core decompression is a safe and effective treatment modality for symptomatic osteonecrosis of the wrist at the distal radius and/or ulna. Although the level of improvement in MHQ varied for each case, all patients reported reduced pain and improved function at final follow-up without any apparent complications. Based on these results, we recommend the use of core decompressions to alleviate the symptoms and to possibly delay the progression of distal radius osteonecrosis.

Introduction: Core decompression has historically been used during the early stages of osteonecrosis of the ankle as a treatment method to decrease pain and defer the eventual collapse of the joint. Originally, this procedure was described using large diameter trocars. The multiple locations of the lesions (such as the distal tibia and fibula, the talar dome, the calcaneus, and/or the metatarsals) and the relative small affected bones (compared to the femoral head and distal femur) make this procedure technically difficult. The investigators report on the treatment of osteonecrosis of the ankle with a new technique using multiple small percutaneous 3-mm perforations.

Methods: Between September, 2002 and May, 2004, the senior author treated 44 symptomatic ankles affected with osteonecrosis using the multiple perforation technique. The series included 31 patients (23 women, 8 men) who had a mean age at the time of surgery of 42 years (range, 17 to 61 years). All the procedures were performed using a 3-millimeter Steinman pin technique. Radiographic outcome was assessed during post-operative clinical visits using plain x-rays and magnetic resonance imaging. Clinical outcome was assessed postoperatively using the AOFAS (American Orthopaedic Foot and Ankle Society) score. Progression of the disease (defined as evidence of subchondral collapse or AOFAS score < =80 points) was correlated with demographic variables such as associated risk factors, prior surgical procedures, size, and location of the lesions.

Results: Ankle arthrodesis was avoided in 93% of the cases (41 of 44 ankles) at a mean follow-up of 3.6 years (range, 2 to 5 years). Forty of 44 ankles (91%) had a successful clinical outcome (AOFAS score ≥ 80 points). The AOFAS score for the entire series increased from a preoperative mean of 41 points (range, 34 to 55 points) to a postoperative mean of 88 points (range, 51 to 100 points). The AOFAS score for the series excluding the three ankles that required arthrodesis increased from a preoperative mean of 41 points to 91 points postoperatively. The three cases that required ankle arthrodesis presented initially with osteonecrosis of multiple bones about the ankle (talus, calcaneus, distal tibia and fibula) and two of these cases had HIV as an associated risk factor for osteonecrosis. All but 8 patients presented signs and symptoms of osteonecrosis in other joints (hip, knee, shoulder) and this had a negative correlation with outcome. There were no complications from the procedures, which were all performed as outpatient surgeries.

Discussion: The percutaneous perforations technique appears to be a low-morbidity method of relieving symptoms and deferring ankle arthrodesis (or other invasive procedures) in patients with symptomatic osteonecrotic ankles. The authors believe that these results support the need for a multicenter-randomized study comparing minimally invasive treatment options for osteonecrosis.