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

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.

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

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.

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.

Introduction: Osteonecrosis or avascular necrosis is a debilitating disease that can affect various joints such as the shoulder and knee, but it is most common in the hip. These cases may be challenging, and it is important that orthopaedic residents receive adequate training concerning the associated risk factors, diagnosis, and treatment modalities commonly used in treating this disease. Current scientific publications are often recommended as one of the main sources of information for surgeons in training. The purpose of the present study was to characterize the osteonecrosis information provided in the peer-reviewed literature, and to analyze the osteonecrosis related knowledge frequently tested on the Orthopaedic In-Training Examination (OITE). In addition, we assessed the relevance of recent literature as a tool for young physicians who are learning more about osteonecrosis as they prepare for their board examinations.

Methods: A systematic review was conducted using the Medline bibliographic databases of all literature from 5 years (2001–2005) in 4 high-impact orthopaedic journals (a total of 6750 articles): The Journal of Bone and Joint Surgery American (JBJS), Clinical Orthopaedics and Related Research (CORR), Journal of Arthroplasty (JOA), and Journal of Orthopaedic Research (JOR). For each year, the total number of articles and the number of articles related to “osteonecrosis” or “avascular necrosis” were determined. All articles were screened by two reviewers and grouped as having either a primary or secondary focus on osteonecrosis. The primary focus articles were stratified according to four subject areas including: etiology/associated risk factors, pathology/pathophysiology, diagnosis/classification, and treatment. Articles related to the treatment of osteonecrosis were further stratified according to non-invasive (such as pharmacological treatment and shock wave), core decompressions and nonvascularized graftings, revascularization techniques, osteotomies, and replacement surgeries (such as total hip arthroplasty and hemi- and total hip resurfacing). Next, the OITE was reviewed for each of the five years that followed the published literature (2002–2006). The questions were stratified in a similar manner as the literature. The overall proportions and the percentages in each category were compared between the OITE questions and the literature.

Results: Overall, 136 (2.0%) articles had an osteonecrosis primary focus, and 115 (1.7%) had a secondary focus. There were 30 primary focus articles every year except for 2002 when there were 16. Out of the four journals reviewed, CORR had the highest percentage of etiology and risk factor related articles (25%), whereas JOR was the most concentrated in pathology (33%) and diagnosis/classification (33%). JOA articles were mostly focused on treatment (83%). The percentage of OITE questions (0.6%) that had a primary osteonecrosis focus was statistically lower than the overall percentage of osteonecrosis articles (p < 0.001). The percentage of articles in each category was also different. Grouped by treatment, etiology/risk factors, pathology, and diagnosis/classification, there were 55%, 22%, 12%, and 11% for the articles and 25%, 25%, 0%, and 50% for the OITE questions. Additionally, the treatment questions in the OITE only focused on THA, but more than half of the articles discussing treatment reported other modalities such as vascularized bone grafting and the use of pharmacological agents.

Conclusions: Knowledge of the content and type of articles in literature can guide residents as they continue their education and learn more about osteonecrosis. All of the journals reviewed in this study provide an overall greater percentage of articles that are focused on osteonecrosis than the proportion of OITE questions. The results of this study suggest that students preparing for the OITE would benefit most by studying those articles that are related to the diagnosis/classification of osteonecrosis. Conversely, the OITE could more accurately reflect the literature by providing future questions concerning the pathology and the different treatment modalities frequently used depending on the stage and progression of this disease.

Introduction: Osteonecrosis of the hip is a devastating disease that often results in the collapse of the femoral head and secondary osteoarthritis of the hip. Although total hip arthroplasty is considered the main therapeutic option in cases of advanced osteonecrosis (Ficat stage III or IV), historically high failure rates have been reported for this treatment. Variables such as, whether or not the prosthesis was cemented, year of implantation, age, various medical comorbidities, and risk factors such as alcohol abuse, corticosteroids usage, autoimmune disease, or sickle cell anemia may lead to better or worse outcomes. The purpose of this study was to determine which factors were associated with risk for failure concerning total hip arthroplasty (THA) for osteonecrosis of the femoral head from a complete meta-analysis of the literature.

Methods: A systematic review utilizing the Medline bibliographic database found 35 studies meeting our inclusion criteria that were related to osteonecrosis encompassing 557 hips in 443 patients. These reports were published between the years 1989 to 2007. The mean follow-up was 6.7 years (range, 3 – 10). The study population comprised of 60% men who had a mean age of 47 years (range, 17 to 90). The most frequent associated risk factors for osteonecrosis were corticosteroid usage (26.2%) and alcohol abuse (30.1%). The final outcome parameters were number and percentage of patients who underwent revision surgery, who had impending radiographic failure, such as osteolytic lesions in close proximity to the implant, or who were clinical failures. Clinical failure was defined as a value less than 70% of the maximum score of the relevant hip scoring system used.

All reviewed studies were divided into cemented, cementless, or hybrid fixation, as well as year of implantation (before and after 1990). In addition, patients were stratified according to comorbidities, age, gender, and various diagnostic and other risk factors (e.g. systemic lupus erythematosus, sickle cell disease, use of corticosteroids, alcohol abuse).

Results: Overall, there were 131 poor outcomes out of 557 hips (23.5%). Seventy-six revision surgeries were performed, with another 55 hips showing either radiographic signs of loosening or clinical failures. Cemented THA had a failure rate of 17.9%, while the cementless THA had a failure rate of 24.5%.

Overall outcomes were different for various risk factors; intake of corticosteroids led to a failure rate of 42.3%, alcohol abuse; 38.1%, posttraumatic disorders; 39%, and sickle cell anemia; 45.5%. Patients without known adverse risk factors had only 17% failures.

Discussion: Our findings further emphasize the poor results of total hip arthroplasty in patients with various risk factors such as alcohol abuse, use of corticosteroids, lupus, and sickle cell anemia. It also appears that patients without these adverse risk factors have a better survival rate. The importance of this study is that it may help the surgeon understand the risk of total hip arthroplasty in various stratified groups in patients with osteonecrosis.

Introduction: A number of surgical techniques have been described for the operative treatment of late stage osteochondritis dissecans (OCD) in the knee and ankle that have failed nonoperative management. However, no particular technique has been universally successful. We report the results of a new technique using retrograde drilling combined with the use of a novel collagen based bone void filler to prevent mechanical failure of the joint surface. The purpose of this study was to evaluate the results of this new technique and analyze the efficacy of both collagen Type-1 based osteoinductive bone void fillers Colloss and Colloss E with and without additional bone grafting.

Methods: The osteoinductive bone void fillers Colloss (bovine) and Colloss E (equine) are bone inducing collagenous sponges. The osteoinductive properties are due to the interactive release of BMP-2, BMP-7, IGF-1 and TGF-beta from the implant and the surrounding host tissue by osteoclastic and osteoblastic action. All surgeries performed in the present series included retrograde drilling procedures for OCD in the talar dome and the femoral condyles. Between 2000 and 2006 eight patients were treated by retrograde drilling or trephine drilling under arthroscopic and fluoroscopic control preventing injury to the cartilage surface. The subchondral cavity was filled with a mixture of 20–40 mg bone void filler and morsellized bone graft. The bone void filler is tamped through the drill guide and into position with a Steinmann pin. Thus, only the subchondral defect was filled but the peripheral area of the drill hole remained empty. Evaluation was achieved by clinical assessment, radiographic, and magnetic resonance imaging examination. The follow-up averaged 24 months up to 48 months.

Results: In all cases, osseous density increased in the Colloss filled subchondral area and mechanical impression of the joint surface could be prevented. Interestingly, clinical examination and follow-up MRI exams demonstrated moderate swelling and joint effusion in 5 of 8 cases for a period of 4 to 10 weeks postoperatively. This may be in part due to the augmentation technique. Nevertheless, good clinical (range of motion, pain) and radiographic results (bony healing) were obtained after this new treatment modality.

Discussion: The subchondral application of Colloss in OCD bone cysts or osteonecrosis induced solid osseous formation at the implantation site. The results of persisting joint reaction such as swelling, pain, and prolonged bone edema in MRI scans may be due to mechanical bearing indicating that augmentation of the defect has to be improved to ensure a solid bony reconstruction. Major advantages of this technique include the ease of performing this procedure, the one-step nature of the procedure, and the ability to avoid violation of stable articular cartilage. In addition, this technique may be repeated according to the size of the lesion.

The Johns Hopkins University Department of Orthopaedics at the Good Samaritan Hospital, Baltimore, Maryland USA

Introduction: Historically, bone scintigraphy has been advocated as a useful diagnostic tool for patients with suspected osteonecrosis or in screening for multifocal disease. The principle aim of this study was to evaluate the sensitivity of bone scanning relative to magnetic resonance imaging in the diagnosis of osteonecrosis.

Methods: Forty-eight patients presented with suspected osteonecrosis of the shoulder, hip, knee, or ankle. All patients underwent simultaneous (less than three months apart) bone scans and magnetic resonance imaging studies as part of a diagnostic work-up. Histological confirmation of osteonecrosis was obtained for all suspected lesions in the study. The diagnostic yield for each imaging modality was then assessed and compared.

Results: All one hundred sixty-three (100%) histologically confirmed lesions were identified by magnetic resonance imaging, while only ninety-one lesions (56%) were identified by bone scan. There was complete uniformity of bone scans with magnetic resonance images in only 38% of patients (eighteen of forty-eight). Bone scanning identified 72% of lesions (forty-seven of sixty-five) in oligofocal patients (less than two involved joints) compared with 45% of the lesions (forty-four of ninety-eight) in multifocal patients (more than two joints involved). Sensitivity of the lesions was highest for the knee and hip and lower for the shoulder and ankle. Larger and later stage lesions had higher bone scan sensitivity.

Conclusions: The results of this study have demonstrated the low sensitivity of bone scintigraphy for diagnosing symptomatic osteonecrosis. Bone scanning did not detect 44% of the lesions (seventy-two of one hundred sixty-three). This study does not support the use of bone scans as a diagnostic or screening tool for this disease.

Introduction: Osteonecrosis of the femoral head is a devastating disease that often progresses to hip joint destruction necessitating total hip arthroplasty. The use of core decompression is typically recommended for patients with early small and medium-sized lesions. The reported efficacy of this procedure has been variable. Recently, various adjustments to the surgical technique have been described. There has been interest in performing multiple drillings under fluoroscopic guidance and combining core decompression with electrical stimulation and/or biological adjunctive growth factors. In order to assess whether the efficacy of this procedure has improved during the last 15 years using modern techniques, we compared recently reported radiographic and clinical success rates to results of surgeries performed prior to 1992. In addition, we evaluated the outcomes of our cohort of 52 patients (79 hips) who were treated with multiple small diameter drillings.

Method: A systematic review utilizing the Medline and Embase bibliographic databases found 59 studies meeting our inclusion criteria that were related to core decompression and osteonecrosis. The mean age for patients was 39 years (range, 9 to 83 years), and the mean follow-up was 56 months (range, 1 to 228 months). From these reports, there were 1,429 hips treated prior to 1992 and 1,957 hips since 1992. Other than the smaller percentage of Ficat stage III cases in the later studies, the reported etiologies and the stratification of preoperative Ficat stage were similar in the two strata of groups with the majority of patients being Ficat stage I and II and corticosteroids and alcohol being the most frequently reported associated diagnosis. From our institution, we identified 52 patients (79 hips) who had a core decompression utilizing a multiple small diameter (3 millimeters) technique at mean follow-up of 65 months. The outcome parameters collected for each core decompression patient at our institution and from the reports in literature were the number and percentage of patients who required additional surgeries, were clinical failures, or had radiographic progression of the disease.

Results: Overall, the success rates were higher for the studies that reported core decompressions performed during the last 15 years compared to procedures that were done prior to 1992. The proportion of patients surviving without additional surgery increased from 57% (range, 28 to 97%) in the earlier studies to 67% (range, 18 to 100%) in the more recent reports. Similarly, the radiographic success also increased from 54% (range, 0 to 94%) for the pre-1992 cohort to 59% (range, 22 to 90%). While clinical success increased from 57% (range, 28 to 94%) in the pre-1992 procedures to 61% (range, 29 to 90%) in reports from the last 15 years, this improvement was not statistically significant. Stratification by Ficat stage showed that there were significantly fewer patients who were Ficat stage III after 1992 suggesting that patient selection was the primary reason for the improvement in outcomes. For hips classified as Ficat stage II, there was an increase in clinical success and reduced percentage of patients requiring additional surgery in the more recent reports. The results of our cohort of patients were similar to other reports in the last 15 years. Patients who had small lesions and were Ficat stage I prior to treatment had the best results with 79% showing no radiographic progression.

Discussion: The results of the present study do not provide adequate evidence to suggest that recent techniques provide better clinical scores or radiographic outcomes. However, the additional accumulation of successful reports in the last decade confirms that core decompression is a safe and effective procedure for the treatment of early stages of osteonecrosis of the femoral head. Furthermore, these results suggest that proper patient selection can improve outcomes for this procedure. Based on the results of our experience as well as that of other studies, we will use core decompression to treat patients who have early small and medium-sized lesions and are Ficat stage I or II. Additionally, the mid-term follow-up of the multiple small diameter core decompression patients at our institution was longer than most studies, and had a success rate similar to, or higher than other reports, which confirms the use of this technique as the authors’ preferred method.

Introduction: Osteonecrosis of the knee occurs with approximately 10% of the incidence of osteonecrosis of the hip. Core decompression is a minimally invasive technique which can potentially forestall bony collapse and thus avoid the need for joint arthroplasty. The purpose of this study was to evaluate the efficacy of a new minimally invasive approach using a small diameter Steinman pin to perform core decompression of the knee.

Materials and Methods: Between September 5, 2000 and May 30, 2003, the senior author performed 55 core decompressions of the knee in 39 patients with symptomatic osteonecrosis of the knee. All procedures were performed using the small-bit drilling technique. There were 32 women and 7 men who had a mean age of 43 years (range, 18 to 52 years). Radiographic and clinical outcomes were assessed during post-operative clinical visits, with persistent pain, loss of joint space, or progression to total knee replacement considered failures.

Results: There were excellent or good outcomes in 45 knees (82%) at a mean three year follow-up (range, 2 to 5 years). Four patients had symptomatic knees that led to total knee arthroplasty. There were no complications from the procedures which were all performed as out-patient surgery.

Discussion: The percutaneous drilling technique appears to be a low-morbidity method of relieving symptoms in patients with symptomatic knees from osteonecrosis. These short-term results are encouraging for this difficult to treat disease.

Introduction: Multiple classification systems for avascular necrosis of the hip have been developed to assist physicians in the diagnosis and treatment of this potentially debilitating disorder. However, this lack of consistency makes clinical decision making difficult when comparing publications. The purpose of this study was to quantify the classification systems reported since 1985 (post-MRI) and identify consistent factors which would allow cross-publication comparisons to be made.

Materials and Methods: The authors performed a PubMed search for reports of outcome studies concerning treatment methods of hip avascular necrosis that were the initial basis for analysis. All studies reported since 1985 were included in the analysis if outcomes of greater than 10 patients treated for this disease were reported. Classification systems utilizing at least one factor were also identified. Tabulation of how frequently these classification systems were used in terms of the number of studies reporting results was performed.

Results: Fifteen major classification systems utilizing more than one radiographic factor were identified with 9 having one to three modifications reported throughout the literature. Additionally, 14 systems utilized either MRI or anatomic factors. Cross-publication analysis revealed five major classification systems which were utilized in greater than 80% of the reported studies.

Discussion: This analysis of the reported classification systems for avascular necrosis of the femoral head revealed several similarities between systems. A cross system analysis can be made if data is collected according to patient symptoms, magnetic resonance imaging findings, and x-ray findings which would allow for the use of any staging system.

Introduction: The results of total hip arthroplasty in patients with avascular necrosis of the hip have been variable. This study analyzed the clinical and radiographic outcome of young patients treated with Four different cementless systems, three with alumina-on-alumina bearings in comparison to a control metal-on-poly couple in young patients with avascular necrosis of the femoral head.

Materials and Methods: This was a US IDE multicenter prospective randomized clinical trial begun in 1996 to evaluate safety and effectiveness of alumina-alumina bearings in young patients. Four cementless systems were compared in 95 patients (105 hips), three alumina-on-alumina bearing systems: ABC System I, porous coated cup; ABC System II, hydroxyapatite coated cup; Trident system, hydroxyapatite coated cup with metal sleeve backing on ceramic cup liner. The control group was the ABC System III, porous coated cup with polyethylene and cobalt chromium bearing system. All patients received a cementless Omnifit HA femoral stem. Patients were randomized to receive ABC System I, II, or III. Trident patients (Study arm begun in 1999) were not randomized. Examinations were performed at 7 weeks, 6 months, 1 year, and yearly thereafter including x-rays, clinical exam and modified Harris Hip Scores (HHS).

Results: For the alumina-alumina hips patients had a mean age of 45 years (21–67) with 18 women (23%) and 61 men (77%) at a mean follow up of 4.2 years (range, 2–7). The mean HHS at latest evaluation was 96 points. There were three revisions: one revision of all components for hip pain (sepsis suspected but not confirmed); one stem and head for traumatic postoperative periprosthetic femoral fracture; and one insert and head for subluxation in a patient implanted with the Trident insert and head. For the metal-poly hips, there were similar demographics, follow-up, and clinical scores. There were two revisions; one stem and head for traumatic postoperative periprosthetic femoral fracture, and one insert only 2 days after index surgery for dislocation.

Discussion: Both bearing couples (alumina-alumina and metal-poly) did well in theses cementless hip arthroplasties performed in young patients with avascular necrosis of the femoral head. The low revision rate is encouraging for these previously difficult to treat patients.

Introduction: The authors systematically reviewed the available literature in order to define the outcomes for avascular necrosis (AVN) and spontaneous osteonecrosis of the knee (SPONK) after unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA).

Materials and Methods: A literature review yielded seven reports with Hospital for Special Surgery (HSS) or Knee Society Score (KSS) outcomes for arthroplasty secondary to either AVN or SPONK. The mean pre-operative, post-operative, and difference in KSS or HSS scores plus the mean revision rates for the arthroplasties for each underlying disease (AVN and. SPONK) were tabulated and reported in this order. The reported means were weighted by the number of knees in each study.

Results: A total of 63 TKAs were performed for AVN and 85 TKAs were performed for SPONK. Additionally, 74 UKAs were performed for SPONK. TKAs performed secondary to AVN had mean KSS scores of 50.6, 90.2, and 39.4 points. The revision rate was 12.5% (SD=10.45). TKAs performed for SPONK had mean HSS scores of 55.6, 82.5, and 27 points. The revision rate was 5.9% (SD=2.79). UKAs performed for SPONK had mean HSS scores of 54, 83.1, and 29.1 points with a revision rate was 9.7% (SD=5.9).

Discussion: Although the KSS for TKAs performed for AVN match the KSS performed in osteoarthritic patient populations receiving TKAs, the revision rate is higher in the AVN group. The HSS scores for patients with SPONK receiving TKAs or UKAs are similar although the revision rate is higher for UKAs.

Introduction: Metal-on-metal resurfacing is a type of total hip arthroplasty that is conservative on the femoral side. It is controversial whether this procedure should be used in patients with avascular necrosis where the femoral resurfacing component is cemented on dead bone. This study analyzed the clinical and radiographic outcome of patients with avascular necrosis treated with metal-on-metal total hip resurfacing arthroplasty.

Materials and Methods: Thirty-seven patients (41 hips) treated with late-stage avascular necrosis of the hip with a metal-on-metal resurfacing hip arthroplasty were studied. There were 27 men and 10 women who had a mean age of 40 years (range, 16 to 62 years). Patients were followed both clinically and radiographically for a minimum of two years (mean of 3 years).

Results: Overall, there were good and excellent clinical outcomes in 38 hips (93%). Fair results were found in three patients who had excessive heterotopic bone (2 hips) and persistent groin pain (1 hip). There were no cases of component loosening. Radiographic zonal analysis revealed no evidence of impending failure or progressive radiolucencies.

Discussion: Excellent short-term results were found with metal-on-metal total hip resurfacing in this difficult patient population. The authors await long-term results to see if these early excellent results are maintained.

Introduction: The results of total hip arthroplasty in patients with avascular necrosis of the hip have been variable. This study analyzed the clinical and radiographic outcome of young patients (mean age of 39 years) treated with a proximally hydroxyapatite-coated tapered stem.

Materials and Methods: Sixty-seven patients (84 hips) treated with late-stage avascular necrosis of the hip with a proximally hydroxyapatite-coated tapered stem as part of their total hip arthroplasty was studied. There were 41 men and 26 women who had a mean age of 39 years (range, 18 to 80 years). Patients were followed both clinically and radiographically for a minimum of two years (mean of 3 years).

Results: Overall, there were good and excellent clinical outcomes in 78 hips (93%). Fair results were found in five patients with persistent pain. There was only one stem loosening (obese patient with SLE). Radiographic zonal analysis revealed no evidence of impending failure or progressive radiolucencies.

Discussion: Excellent short-term results were found with total hip arthroplasty in this difficult patient population. The proximally hydroxyapatite-coated tapered stem utilized in this study was useful in patients with avascular necrosis of the hip.

Introduction: Avascular necrosis of the knee has recently been described to occur after various arthroscopic procedures around the knee. In this report, we described 19 cases that were treated with either a uni- or tri-compartmental knee arthroplasty.

Materials and Methods: In this study, we characterized nineteen patients (19 knees) that were treated with a diagnosis of avascular necrosis that occurred after a knee arthroscopy. All of the knees had magnetic resonance imaging prior to the arthroscopy that was negative for avascular necrosis. Knees in the study had positive MRI findings and severe symptomatology requiring further treatment. Operative procedures performed included unicondylar (n=3) and total knee arthroplasties (n=16).

Results: Six patients had an arthroscopy with laser treatment, 7 had radiofrequency assistance, while 6 others had no special adjuncts. There were 5 men and 14 women with a mean age of 69 years (range, 42–86). All knees were doing well clinically (mean Knee Society Score of 95 points, range 91–100), at a mean follow-up of 4 years (range, 2 to 7 years). Minimally invasive approaches were utilized for all knees.

Discussion: Avascular necrosis of the knee after arthroscopy is an uncommon and not well-characterized disorder. It can be successfully treated with minimally invasive uni or tri-compartmental knee arthroplasty,

Thirty shoulders, in 20 patients, which had undergone core decompression for symptomatic avascular necrosis of the humeral head were reviewed 2 to 14 years later (average 5.6). Twenty-two showed good or excellent clinical results; the other eight shoulders had required arthroplasty. All 14 shoulders with stage I or II radiological changes (Ficat and Arlet 1980) at operation had good or excellent results. We advocate early core decompression for symptomatic avascular necrosis of the humeral head.

Retrospective review of 730 consecutive primary uncemented and cemented total hip arthroplasties revealed 19 intra-operative hoop-stress fractures of the femoral neck. These were incomplete, linear, and minimally displaced. Management was by cerclage wiring (12), bone graft and cerclage (two), further impaction (two), and the use of cement (three), with no change from our standard postoperative management and rehabilitation. Eighteen patients had excellent or good results with an average Harris hip score of 93. Radiographically, all but one patient had Engh stability-fixation scores consistent with stable bone ingrowth. We conclude that hoop-stress fractures of the proximal femur, properly managed, do not detract from the results of total hip arthroplasty.