Introduction

The Center for Medicare and Medicaid Services (CMS) is faced with a challenge of decreasing the cost of care for total knee arthroplasty (TKA), but must make efforts to prevent patient selection bias in the process. Currently, no appropriate modifier codes exist for primary TKA based on case complexity. We sought to determine differences in perioperative parameters for patients with “complex” primary TKA with the hypothesis that they would require increased cost of care, prolonged care times, and have worse postoperative outcome metrics.

Introduction

Debridement, antibiotics, and implant retention (DAIR) for acute prosthetic hip infection is a popular low morbidity option despite less than optimal success rates. We theorized that the delay between DAIR and explantation in failed cases may complicate eradication due to biofilm maturation and entrenchment of bacteria in periprosthetic bone. We ask, what are the results of two-stage reimplantation after a failed DAIR versus an initial two-stage procedure?

Introduction

Hypoalbuminemia has previously been identified as an independent predictor of postoperative complications following total knee arthroplasty (TKA). Given the morbidity and financial burden associated with TKA complications, significant effort has gone into identifying patients at increased risk for perioperative complications. The American Society of Anesthesiologists (ASA) physical status score has been utilized for risk stratification of surgical patients for many years and is a measure of overall health. However, it is unclear how measures like albumin compare to the prognostic ability of this type of global health measure. This study aims to elucidate the utility of preoperative albumin compared with that of the ASA score in predicting complications following TKA.

Introduction

Vitamin D deficiency is common in patients undergoing total hip (THA) or total knee arthroplasty (TKA) which may affect prosthesis survival and 90-day readmission rates. The purpose of this study was to assess whether preoperative Vitamin D deficiency or insufficiency have an influence on revision, readmission, and complication rates following THA and TKA. We hypothesized that low Vitamin D levels in patients undergoing THA and TKA have a negative effect on revision rates.

Introduction

The number of complex revision total hip arthroplasties (THA) is predicted to rise. The identification of acetabular bone defects prior to revision THA has important implications on technique and complexity of acetabular reconstruction. Paprosky et al. proposed a classification system including 3 main types with up to 3 subtypes focused on the integrity of the superior rim of the acetabulum and medial wall. However, the classification system is complex and its reliability has been questioned. The purpose of this study was to evaluate the effectiveness of different radiologic imaging modalities (plain radiographs, 2-D CT, 3-D CT reconstructions) in classifying acetabular defects in revision hip arthroplasty cases and their value of at different levels of orthopaedic training.

Introduction

Unicompartmental knee arthroplasty (UKA) has seen renewed interest in recent years and is a viable option for patients with limited degenerative disease of the knee as an alternative to total knee arthroplasty. However, the minimally invasive UKA procedure is challenging, and accurate component alignment is vital to long-term survival. Robotic-assisted UKA allows for greater accuracy of component placement and dynamic intraoperative ligament balancing which may improve clinical patient outcomes. The purpose of this study was to analyse the clinical outcomes in a large, consecutive cohort of patients that underwent robotic-assisted UKA at a single institution with a minimum follow-up of 2 years. The study hypothesis was that robotic-assisted UKA improves patient outcomes by decreasing the rate of revision in comparison to conventional UKA.

Introduction

Unicompartmental knee arthroplasty (UKA) has seen renewed interest in recent years due to improved surgical techniques and prosthetic design, and the desire for minimally invasive surgery. For patients with limited degenerative disease, UKA offers a viable alternative to total knee arthroplasty. Historically, the outcomes of lateral compartment UKA have been inferior to medial compartment UKA, with suboptimal patient satisfaction and increased revision rates. Robotic-assisted UKA has been shown to improve precision and accuracy of component placement, which may improve outcomes of lateral UKA. The purpose of this study was to compare the outcome of robotic-assisted UKA to conventional UKA for degenerative disease of the lateral compartment. The hypothesis of the study was that robotic-assisted lateral UKA results in superior outcomes compared to conventional UKA.

Robots have been used in surgery since the late 1980s. Orthopaedic surgery began to incorporate robotic technology in 1992, with the introduction of ROBODOC, for the planning and performance of total hip replacement. The use of robotic systems has subsequently increased, with promising short-term radiological outcomes when compared with traditional orthopaedic procedures. Robotic systems can be classified into two categories: autonomous and haptic (or surgeon-guided). Passive surgery systems, which represent a third type of technology, have also been adopted recently by orthopaedic surgeons.

While autonomous systems have fallen out of favour, tactile systems with technological improvements have become widely used. Specifically, the use of tactile and passive robotic systems in unicompartmental knee replacement (UKR) has addressed some of the historical mechanisms of failure of non-robotic UKR. These systems assist with increasing the accuracy of the alignment of the components and produce more consistent ligament balance. Short-term improvements in clinical and radiological outcomes have increased the popularity of robot-assisted UKR.

Robot-assisted orthopaedic surgery has the potential for improving surgical outcomes. We discuss the different types of robotic systems available for use in orthopaedics and consider the indication, contraindications and limitations of these technologies.

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 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: Musculoskeletal injuries of the shoulder in paraplegic patients can result from overuse and/or incorrect use of wheelchairs. With improved long-term survival of these patients who exclusively depend on their upper extremities for weight-bearing activities such as transfers and wheelchair propulsion, they are particularly susceptible for shoulder pathologies. The purpose of this study was to compare the functional and structural changes in weight-bearing shoulders of paraplegic patients who are wheelchair dependent for more than 30 years with able-bodied volunteers.

Methods: This was a randomized study with 80 (160 shoulders) patients who had been paraplegic and wheelchair dependent for a mean of 33 years. These patients were matched for gender, age, occupation, and hobbies to a group of 80 (160 shoulders) able-bodied volunteers. The mean age for the paraplegic patients was 54 years and 51 years for the matched volunteers. Shoulders from both groups were prospectively evaluated using MRI. All films were analyzed by two board-certified radiologists who were blinded to the study. Prospectively collected outcome measures included a standardized clinical examination protocol, the Constant score, and visual analog scale (VAS) pain scores.

Results: The shoulder function according to the Constant score was significantly worse in paraplegic patients compared to able-bodied volunteers (p< 0.001). Similarly, the VAS scores were significant greater in the paraplegic patients (three-fold higher pain intensity, p< 0.001). Comparison of the MRI films of the paraplegic patients and the volunteers revealed the following significant differences: rotator cuff tears 67% (108/160) vs 5.6% (9/160); tendonitis 50% (80/160) vs 23% (37/160); tendonitis of the long head of the biceps 25% (40/160) vs 3.7% (6/160); rupture of the long head of the biceps 10% (16/160) vs 2.5% (4/160); subacromial subdeltoid bursitis 71% (113/160) vs 34% (55/160); acromioclavicular osteoarthritis 33% (53/160) vs 15% (24/160); and glenohumeral osteoarthritis 15% (24/160) vs 8% (13/160).

Conclusion: This is the first study comparing the long-term effect on shoulder pathologies of paraplegic wheelchair users to a cohort of able-bodied volunteers. The complications of weight-bearing activities in these patients require appropriate prevention including wheelchair and/or home modification, physical therapy, pharmacological pain management, surgical intervention, and patient education.

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: 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.