Natural History of Opioid Use in Naive and Tolerant Patients in Revision Total Hip Arthroplasty

BACKGROUND

Opioid use after revision total hip arthroplasty (rTHA) has not been well characterized. The purpose of this study was to characterize preoperative, perioperative, and postoperative opioid use during rTHA.

METHODS

Patients undergoing revision THA from 2010 to 2018 were screened for opioid use 3 months before revision surgery and tracked 24 months postoperatively. Patients were categorized as naïve or tolerant. Opioid prescriptions and average morphine milligram equivalents (MME) were compared between the two groups.

RESULTS

One hundred twenty-four of 247 patients (50%) in the tolerant group averaged a preoperative MME of 23.7 mg/day. Postoperatively, tolerant patients received significantly higher daily MME at all time points, including at 3 months 31.4 versus 18.1 mg/day (P < 0.001), 6 months 19.9 versus 2.95 mg/day (P < 0.001), 12 months 14.3 versus 3.5 mg/day (P < 0.001), and 24 months 10.7 versus 2.17 mg/day (P < 0.001). Tolerant patients were more likely to have a prescription at 6 months (44% versus 22%), 12 months (41.4% versus 24%), and 24 months (38% versus 19.3%) (P < 0.001, P = 0.002, P < 0.001, respectively).

DISCUSSION

Opioid-tolerant patients had higher postoperative MME requirements for longer recovery duration. Both groups reduced opioid use at 3 months and plateaued at 6 months. These findings can help the revision surgeon counsel patients and expectations.

Intravenous Dexmedetomidine Use in Total Hip Arthroplasty May Lead to Elevated Rates of Hypotension

Purpose Enhanced recovery protocols for total hip arthroplasty (THA), using opioid-sparing techniques have become widely used. Reports of novel additions to multimodal pain control regimens have been published, however, a paucity of literature exists on the use of intravenous dexmedetomidine. In this study, we analyzed our experience with intravenous dexmedetomidine and hypothesized that it would reduce postoperative opioid use. Secondary outcomes were also examined, including post-operative hypotension, hemoglobin, length of stay, and discharge disposition. Methods All patients who underwent primary THA at a single tertiary-level center between January 1, 2016, and September 1, 2019, underwent investigation. Diagnosis, surgical approach, anesthetic type, body mass index (BMI), and American Society of Anesthesiologists (ASA) score were recorded. Postoperative clinical measures were analyzed, adjusting for patient and surgical characteristics. Results Of the 599 patients included in the study, 218 patients received intravenous (IV) dexmedetomidine, at a mean dose of 44.9 mg during their operative event. Using a multivariate model, patients in the IV dexmedetomidine group were estimated to have received 24% elevated morphine milligram equivalent at postoperative day zero compared to those in the control group (p = 0.05). In addition, patients in the IV dexmedetomidine group who underwent spinal anesthesia had increased odds of hypotension 3.47 times that of the control [odds ratio (OR) 1.43-8.43, p=0.006]. Conclusions Surprisingly, we found no opioid-sparing effects with the use of IV dexmedetomidine. IV dexmedetomidine may be used cautiously as an anesthesia adjunct with spinal anesthesia in the setting of primary THA, as the experience at our institution illustrated increased odds of postoperative hypotension. Level of evidence This retrospective case-control study has a level of evidence III.

Coccidioidomycosis in Joint Replacement: A Review of the Literature With Case Presentations

Coccidioidomycosis is a fungal infection endemic to certain regions of the Americas. In some cases, the organism may infect the musculoskeletal system, resulting in a prosthetic joint infection (PJI). Due to its difficulty in diagnosis, treatment of coccidioidomycosis in PJI is often delayed. Furthermore, with limited number of case reports, a standard of care in treatment has yet to be established. We present 2 cases of coccidioidomycosis PJI, the extensive evaluation that led to the diagnosis, and the treatment provided. This report highlights the natural progression of coccidioidomycosis in a prosthetic joint, the diagnostic features including histology, advanced imaging, and final treatment administered.

Survivorship and Etiologies of Failure in Single-stage Revision Arthroplasty for Periprosthetic Joint Infection: A Meta-analysis

INTRODUCTION

Single-stage revision arthroplasty for periprosthetic joint infection (PJI) may yield comparable infection-free survivorship with two-stage revision arthroplasty. It is unclear if the most common mode of failure of single-stage revision arthroplasty is infection or aseptic loosening. In this meta-analysis, we sought to (1) determine survivorship and (2) compare rates of different etiologies of failure of single-stage revision total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

Preferred Reporting Items for Systematic Review and Meta-analyses guidelines search was done using search terms for "single stage revision," "exchange arthroplasty," "periprosthetic infection," "PJI," and "single stage." Patient demographics such as age, body mass index, and mean follow-up time were recorded. Overall survivorship and rates of revision surgery were aggregated using a random-effects model. Comparison of septic and aseptic loosening rates was done by risk difference and associated 95% confidence interval (CI) calculation.

RESULTS

Twenty-four studies were identified with 2,062 and 147 single-stage revision THA and TKA procedures performed between 1984 and 2019, respectively. The weighted mean follow-up and age were 69.8 months and 66.3 years, respectively, with 55% men overall. The all-cause revision surgery rate was 11.1% and 11.8% for THA and TKA, respectively. The revision surgery rate secondary to infection and aseptic loosening and associated 95% CI for the risk difference for THA and TKA was 5.5% and 3.3% (-1.7% to 5.0%), and 3% and 8.8% (-11.4% to 2.3%), respectively. Revision surgeries due to instability and fracture combined and mortality rate were both less than 3%.

DISCUSSION

Single-stage revision THA and TKA for PJI demonstrated overall high rates of survivorship, low mortality, and revision surgeries secondary to infection and aseptic loosening to be equivalent. Aseptic loosening after single-stage revision TKA might be higher than in primary TKA. As implant survivorship from infection improves in PJI, surgeons should be aware of aseptic loosening as an equally common mode of failure.

Tantalum Cementless Versus Cemented Total Knee Arthroplasty: A Meta-analysis of Level 1 Studies

INTRODUCTION

Controversy exists on the ideal type of fixation in total knee arthroplasty (TKA). Noncemented fixation has been theorized to improve patient outcomes and longevity of implantation without increased risk of aseptic loosening or radiolucent lines. We sought to compare (1) patient-reported outcomes, (2) survivorship, and (3) revision rates for all-cause and aseptic loosening in a noncemented tantalum total knee with its cemented counterpart.

METHODS

Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines were searched using a combination of keywords "trabecular metal," "tantalum knee," "total knee arthroplasty," and "cementless trabecular." Patient demographics such as age, sex, and body mass index were collected. Outcomes such as Knee Society Scores (KSSs), revisions, and radiolucent lines were recorded for analysis.

RESULTS

Four randomized controlled trials involving 507 patients with an average 5-year follow-up were eligible for meta-analysis. No differences were observed in any demographics such as age, sex, body mass index, nor preoperative KSS. Patients in the cemented cohort improved from preoperative KSS 46.4 to postoperative KSS 90.4 while the tantalum cohort improved from 46.4 to 89.3. No statistical difference was observed in postoperative KSS mean difference between groups. Six patients from the tantalum group underwent revision with one patient for aseptic loosening. Twelve patients from the cemented group underwent revision with four patients for aseptic loosening. No statistical difference was observed between rates of revision, aseptic loosening, or radiolucent line development.

DISCUSSION

Patient-reported outcomes improved postoperatively in both groups. No differences were detected between the cemented and noncemented TKAs in patient-reported outcomes, revision rates, or radiolucent line development. Noncemented tantalum fixation seems equivalent to cemented TKA survivorship. Longer term follow-up of these randomized controlled trials may provide a clearer understanding whether a difference exists.

Utility of D-dimer in total joint arthroplasty

As the number of patients receiving total joint replacements continues to rise, considerable attention has been directed towards the early detection and prevention of postoperative complications. While D-dimer has long been studied as a diagnostic tool in venous thromboembolism (VTE), this assay has recently received considerable attention in the diagnosis of periprosthetic joint infection (PJI). D-dimer values are substantially elevated in the acute postoperative period after total joint arthroplasty, with levels often exceeding the standard institutional cutoff for VTE (500 µg/L). The utility of D-dimer in detecting VTE after total joint replacement is currently limited, and more research to assess its value in the setting of contemporary prophylaxis protocols is warranted. Recent literature supports D-dimer as a good to excellent biomarker for the diagnosis of chronic PJI, especially when using serum sample technique. Providers should exercise caution when interpreting D-dimer levels in patients with inflammatory and hypercoagulability disorders, as the diagnostic value is decreased. The updated 2018 Musculoskeletal Infection Society criteria, which includes D-dimer levels > 860 µg/L as a minor criterion, may be the most accurate for diagnosing chronic PJI to date. Larger prospective trials with transparent lab testing protocols are needed to establish best assay practices and optimal cutoff values for D-dimer in the diagnosis of PJI. This review summarizes the most current literature on the value of D-dimer in total joint arthroplasty and elucidates areas for future progress.

Infection and Mortality Rate in Hepatitis C and Cirrhotic Patients Undergoing Hip and Knee Replacement

Liver disease carries significant risk in total joint arthroplasty (TJA). The authors sought to investigate the complications in hepatitis C virus (HCV) and cirrhosis patients after TJA. PRISMA guidelines extracted ten studies and meta-analytic analysis was performed. Five hundred and twenty-seven patients with liver disease underwent TJA. The complication rate was 38.9%, with 8% infection at 57 months. Cirrhotic patients had higher complication and infection rates compared to HCV patients (p < 0.001, p < 0.039, respectively). Mortality in cirrhosis patients was 17.8% at 36 months. Studies suggested Child Pugh Class A patients had significantly lower complications than Class B or C. One study revealed lower MELD (Model for End-Stage Liver Disease) scores < 10 carry a low mortality risk of 9.8% compared with 32% mortality if MELD score 10 or above. Cirrhosis has significant infection and mortality risk in total hip and knee arthroplasty. Surgeons can risk stratify these patients by MELD score and Child Pugh Class. (Journal of Surgical Orthopaedic Advances 31(1):001-006, 2022).

Rapidly progressive idiopathic arthritis of the hip: incidence and risk factors in a controlled cohort study of 1471 patients after intra-articular corticosteroid injection

OBJECTIVE

Rapidly progressive idiopathic arthritis of the hip (RPIA) is defined by progressive joint space narrowing of > 2 mm or > 50% within 1 year. Our aims were to assess (a) the occurrence of RPIA after intra-articular steroid injection, and (b) possible risk factors for RPIA including: patient age, BMI, joint space narrowing, anesthetic and steroid selections, bone mineral density, and pain reduction after injection.

MATERIALS AND METHODS

A retrospective search of our imaging database identified 1471 patients who had undergone fluoroscopically guided hip injection of triamcinolone acetonide (Kenalog) and anesthetic within a 10-year period. Patient data, including hip DXA results and patient-reported pain scores, were recorded. Pre-injection and follow-up radiographs were assessed for joint space narrowing, femoral head deformity, and markers of osteoarthritis. Osteoarthritis was graded by Croft score. Associations between patient characteristics and outcome variables were analyzed.

RESULTS

One hundred six of 1471 injected subjects (7.2%) met the criteria for RPIA. A control group of 161 subjects was randomly selected from subjects who underwent hip injections without developing RPIA. Compared to controls, patients with RPIA were older, had narrower hip joint spaces, and higher Croft scores before injection (p < 0.05). Patients who developed RPIA did not differ from controls in sex, BMI, hip DXA T-score, anesthetic and steroid injectates, or pain improvement after injection.

CONCLUSION

We found that approximately 7% of patients undergoing steroid hip injection developed RPIA. More advanced patient age, greater joint space narrowing, and more severe osteoarthritis are risk factors for the development of RPIA after intra-articular steroid injection.

Systematic review of single stage revision for prosthetic joint infection

While advanced technology, increased medical knowledge and improved surgical technique has improved patient outcomes in total joint arthroplasty, prosthetic joint infection still remains one of the leading causes of increased healthcare costs, medical resources and societal burdens in orthopaedic care. Two stage arthroplasty revision remains the gold standard for treatment of prosthetic joint infection. Proponents of single stage revision arthroplasty for infection argue that it results in lower healthcare costs while improving patient reported functional outcomes and with equivalent success rates. Here we review the history of single stage revision arthroplasty, discuss the key principles, highlight the indications and contraindications, and review the reported outcomes with a focus on future developments of single stage revision arthroplasty for hip and knee periprosthetic joint infections.

Total Knee Arthroplasty: Fitness, Heart Disease Risk, and Quality of Life

Total knee arthroplasty (TKA) may decrease coronary heart disease (CHD) risk in patients with advanced osteoarthritis by reducing pain and allowing for a more active lifestyle. We examined cardiovascular fitness, CHD risk factors, and quality of life in patients for 1 year after TKA compared with matched controls who did not undergo surgery. A total of 14 patients, 7 surgery patients and 7 matched controls, were tested for measurements of body composition, knee range of motion, resting blood pressure, strength testing, a maximal exercise test, quality-of-life questionnaires (Medical Outcomes Study Short Form-36 and Knee Osteoarthritis Outcome Score [KOOS]), and activity monitoring, fasting blood glucose, and lipids at 0, 3, 6, and 12 months after surgery or baseline testing. Comparison between the two groups was analyzed. Twelve months after surgery, patients with TKA had significantly (p < 0.05) lower pain scores, increased fat free mass, lower resting mean arterial pressure, and improved scores on the KOOS for pain, symptoms, activities of daily living, and quality of life. Initially, total cholesterol, high-density lipoprotein cholesterol, triglycerides, and body fat percentage were reduced in the TKA group but returned to baseline at 12 months. The results of this study indicate that there are immediate and long-term improvements in pain and quality of life in patients with TKA, but physical function, exercise capacity, leg strength, and some lipid profiles may take longer than 12 months to improve. This is a level II, prospective, Therapeutic study, comparative study.

Total Hip Instability and the Spinopelvic Link

PURPOSE OF REVIEW

Advances in technology, implant design, and surgical technique have lowered the dislocation rate in primary total hip arthroplasty (THA). Despite these advances, there remain a large number of instability episodes without a known etiology. Recent research suggests that the pelvic and lumbar spine interrelationship may be the explanation in prosthetic dislocations without a known cause. In this review, we describe the biomechanics, measurements, diagnoses, classification, management, and outcomes of total hip and revision total hip instability as it relates to spinopelvic alignment.

RECENT FINDINGS

As a person goes from standing to sitting, lumbar lordosis decreases, and the sacrum and entire pelvis tilts posteriorly with sacrum and coccyx rotating posterior-inferiorly, resulting in increased acetabular cup anteversion to accommodate femoral flexion. A fused spine and associated fixed acetabulum can result in abnormal pelvic femoral motion, impingement, and dislocation. Classifying the spinopelvic mechanics by sacral motion based on sitting and standing lateral radiographs provides an understanding of how the acetabulum behaves in space. This information helps appropriate cup positioning, reducing the risk of femoral side impingement and subsequent dislocation. Surgical techniques to consider in the spinopelvic at-risk patient are positioning considerations in acetabular cup inclination and anteversion, high offset femoral stems, high offset acetabular liners, dual mobility articulations, and removal of impinging structures. Future research is needed to define the safest order of operation in concomitant hip and spine pathology, the effects on pelvic femoral biomechanics in spine surgery, and whether preoperative and intraoperative management strategies have a long-term beneficial effect on the dislocation rate.

Top 100 most cited articles in orthopaedic surgery: An update

Introduction

As the research landscape evolves, we sought to investigate the current most cited Orthopaedic Surgery articles and compare these to previously cited articles.

Methods

Web of Science database screened orthopaedic journal articles with comparison to previous data using multivariate regression analysis.

Results

Rate of citations increased 172% within the last decade. Previous rank and citations within the last decade had a greater effect on contemporary rank (p = 0.084, p = 0.002, respectively).

Conclusion

Trends in investigative research can shift by the next decade. Previous citation rank and citations in last decade contributed most to current rank.

Mortality During Total Hip Periprosthetic Joint Infection

BACKGROUND

We sought to understand the mortality rate of periprosthetic joint infection (PJI) of the hip undergoing 2-stage revision for infection.

METHODS

Database search, yielding 23 relevant studies, totaled 19,169 patients who underwent revision for total hip PJI.

RESULTS

One-year weighted mortality rate was 4.22% after total hip PJI. Five-year mortality was 21.12%. Average age was 65 years. When comparing the national age-adjusted risk of mortality and the reported 1-year mortality risk in this systematic review, the risk of death after total hip PJI is significantly increased (odds ratio 3.58, P < .001).

CONCLUSION

The mortality rate during total hip revision for infection is high. When counseling a patient regarding complications of this disease, death should be discussed.

Total knee arthroplasty after Hauser procedure: beware of the patellar tendon!

Preoperative planning is a fundamental element in total knee arthroplasty (TKA). A previous surgery that must be recognized and identified preoperatively is the Hauser procedure, a posteromedialization of the tibial tubercle for recurrent patellar instability. Here, we describe 2 case reports in patients with previous Hauser surgeries. The first TKA surgery was complicated from a standard medial peripatellar approach resulting in complete transection of the patellar tendon during standard arthrotomy. The tendon was repaired, and the arthroplasty was aborted. For the second case, correct preoperative identification of the Hauser procedure was performed. The second TKA surgery was performed using a lateral peripatellar arthrotomy with excellent exposure, resulting in a successful operation. Here, we highlight the importance of an accurate history, physical and radiographic examination, and the recommendation of an alternative TKA approach to help avoid the serious intraoperative complication of a patellar tendon laceration.

Female Sex and Longer Fusion Constructs Significantly Increase the Risk of Total Hip Arthroplasty Following Spinal Fusion

BACKGROUND

Previous studies have noted the progression of arthritis due to increased forces in articular structures adjacent to a fused joint. It is unknown whether spinal fusion generates increased forces at the hip joint causing progression to arthritis leading to total hip arthroplasty (THA). We sought to determine (1) is there a relationship between spinal fusion and THA, (2) what are risk factors for subsequent THA, and (3) is there a time interval from spinal fusion to THA?

METHODS

A large patient discharge dataset was utilized to evaluate all patients who underwent spinal fusion and subsequent THA in California from 2004 through 2013. Patients were categorized by age, sex, hospital type, hospital volume, and number of spinal levels fused. Multivariate analysis was performed to investigate the relationship between spinal fusion and THA. Hazard ratios were calculated for risk factors for THA after spinal fusion. Patients were excluded for previous spinal fusion or hip arthroplasty, inflammatory arthropathy, cancer, and an age of ≤40 years, a surrogate for adolescent and neuromuscular scoliosis.

RESULTS

A total of 101,206 patients underwent spinal fusion; 2,803 (2.77%) subsequently underwent THA. In a bivariate analysis comparing 1 to 2 levels versus >2 levels fused, males had a 17% increased relative risk of undergoing subsequent THA (relative risk [RR] = 1.17; 95% confidence interval [CI] = 1.16 to 1.17) and female patients had a 35% increased relative risk (RR = 1.35; 95% CI = 1.34 to 1.35) when the fusion involved >2 levels. For females, the relative risk increased by 119% when >7 levels were fused compared with 1 to 7 levels (RR = 2.19; 95% CI = 2.16 to 2.21). Using multivariate random-effects analysis, significant risk factors for THA after spinal fusion included female sex (hazard ratio [HR] = 1.21; 95% CI = 1.13 to 1.31; p < 0.0001) and spinal fusion of >7 levels (HR = 1.52; 95% CI = 1.03 to 2.24; p = 0.035).

CONCLUSIONS

Patients with longer spinal fusion constructs, especially female patients, had a significantly increased risk of undergoing subsequent THA. Patients should be educated regarding the potential for the progression to hip arthritis after spinal fusion and the possibility of future THA.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Mortality During Total Knee Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infections (PJIs) are fraught with multiple complications including poor patient-reported outcomes, disability, reinfection, disarticulation, and even death. We sought to perform a systematic review asking the question: (1) What is the mortality rate of a PJI of the knee undergoing 2-stage revision for infection? (2) Has this rate improved over time? (3) How does this compare to a normal cohort of individuals?

METHODS

We performed a database search in MEDLINE/EMBASE, PubMed, and all relevant reference studies using the following keywords: "periprosthetic joint infection," "mortality rates," "total knee arthroplasty," and "outcomes after two stage revision." Two hundred forty-two relevant studies and citations were identified, and 14 studies were extracted and included in the review.

RESULTS

A total of 20,719 patients underwent 2-stage revision for total knee PJI. Average age was 66 years. Mean mortality percentage reported was 14.4% (1.7%-34.0%) with average follow-up 3.8 years (0.25-9 years). One-year mortality rate was 4.33% (3.14%-5.51%) after total knee PJI with an increase of 3.13% per year mortality thereafter (r = 0.76 [0.49, 0.90], P < .001). Five-year mortality was 21.64%. When comparing the national age-adjusted mortality (Actuarial Life Table) and the reported 1-year mortality risk in this meta-analysis, the risk of death after total knee PJI is significantly increased, with an odds ratio of 3.05 (95% confidence interval, 2.69-3.44; P < .001).

CONCLUSION

The mortality rate after 2-stage total knee revision for infection is very high. When counseling a patient regarding complications of this disease, death should be discussed.

Survival of the native hip after spinopelvic fusion

Studies describe progression of adjacent joint arthritis after hip fusion but not vise versa. We investigated the relationship after spinopelvic fusion and total hip arthroplasty. 383 patients undergoing spinopelvic were investigated. Perioperative demographics were recorded. A matched 2:1 cohort was used to detect risk factors for THA progression. 10 patients (2.6%) underwent THA after spinopelvic fusion. Average time from surgery to THA was 24.4 months. After spinopelvic fusion, patients progressed to THA 24.4 months on average. Due to small numbers, we couldn't find differences between the two groups regarding comorbidities nor risk factors for THA. Further studies are needed.

Enoxaparin-induced skin necrosis at injection site after total knee arthroplasty

Enoxaparin is a widely used low-molecular-weight heparin for perioperative thromboembolic prophylaxis. Enoxaparin-induced skin necrosis in the setting of arthroplasty has been rarely reported in the literature with varying outcomes and management decisions. Our patient developed skin necrosis at his injection site and thrombocytopenia 10 days following left total knee arthroplasty surgery and after receiving subcutaneous Lovenox injections postoperatively. The patient was started on an alternative anticoagulation based on a high suspicion for heparin-induced thrombocytopenia and the wound was monitored without surgical debridement. Our case highlights the key clinical management decisions when facing this potentially life-threatening adverse reaction.

Postoperative Stiffness Requiring Manipulation Under Anesthesia Is Significantly Reduced After Simultaneous Versus Staged Bilateral Total Knee Arthroplasty

BACKGROUND

For patients with symptomatic bilateral knee arthritis, it is unknown whether the risk of developing stiffness requiring manipulation under anesthesia postoperatively is higher or lower for those undergoing simultaneous bilateral total knee arthroplasty (TKA) compared with those having staged bilateral TKA. Therefore, we undertook this study to evaluate the risk of requiring manipulation under anesthesia in staged versus simultaneous bilateral TKA as well as patients undergoing unilateral TKA.

METHODS

We utilized the California Patient Discharge Database, which is linked with the California Emergency Department, Ambulatory Surgery, and master death file databases. Using a literature-based estimate of the number of patients who failed to undergo the second stage of a staged bilateral TKA, replacement cases were randomly selected from patients who had unilateral TKA and were matched on 8 clinical characteristics of the patients who had staged bilateral TKA. Hierarchical multivariate logistic regression was performed to determine the risk-adjusted odds of manipulation in patients undergoing unilateral TKA, staged bilateral TKA, and simultaneous bilateral TKA using yearly hospital TKA volume as a random effect. Adjustment was made to allow fair comparison of the outcome at 90 and 180 days of follow-up after staged compared with simultaneous bilateral TKA.

RESULTS

During the time period from 2005 through 2013, the cumulative incidence of manipulation within 90 days was 2.14% for unilateral TKA (4,398 events per 205,744 patients), 2.11% for staged bilateral TKA (724 events per 34,352 patients), and 1.62% for simultaneous bilateral TKA (195 events per 12,013 patients). At 180 days of complete follow-up, the cumulative incidence of manipulation was 3.07% after unilateral TKA (6,313 events per 205,649 patients), 2.89% after staged bilateral TKAs (957 events per 33,169 patients), and 2.29% after simultaneous bilateral TKA (267 events per 11,653 patients). With multivariate analyses used to adjust for relevant risk factors, the 90-day odds ratio (OR) of undergoing manipulation after simultaneous bilateral TKA was significantly lower than that for unilateral TKA (OR = 0.70; 95% confidence interval [CI], 0.57 to 0.86) and staged bilateral TKA (OR = 0.71; 95% CI, 0.57 to 0.90). Similarly, at 180 days, the odds of undergoing manipulation were significantly lower after simultaneous bilateral TKA than after both unilateral TKA (OR = 0.71; 95% CI, 0.59 to 0.84) and staged bilateral TKA (OR = 0.76; 95% CI, 0.63 to 0.93). The frequency of manipulation was significantly associated with younger age, fewer comorbidities, black race, and the absence of obesity.

CONCLUSIONS

Although the ORs were small (close to 1), simultaneous bilateral TKA had a significantly decreased rate of stiffness requiring manipulation under anesthesia at 90 days and 180 days after knee replacement compared with that after staged bilateral TKA and unilateral TKA.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Do small changes in rotation affect measurements of lower extremity limb alignment?

BACKGROUND

The alignment of the lower extremity has important implications in the development of knee arthritis. The effect of incremental rotations of the limb on common parameters of alignment has not been studied. The purpose of the study was to (1) determine the standardized neutral position measurements of alignment and (2) determine the effect of rotation on commonly used measurements of alignment.

METHODS

Eighty-seven full length CT angiography studies (49 males and 38 females, average age 66 years old) were included. Three-dimensional models were created using a rendering software program and placed on a virtual plane. An image of the extremity was obtained. Thirty scans were randomly selected, and those models were rotated in 3° intervals around the longitudinal axis and additional images were obtained.

RESULTS

In the neutral position, the mechanical lateral distal femoral articular angle (mLDFA) was 85.6 ± 2.3°, medial proximal tibial angle (MPTA) was 86.1 ± 2.8°, and mechanical tibiofemoral angle (mTFA) was -0.7 ± 3.1°. Females had a more valgus alignment with a mTFA of 0.5 ± 2.9° while males had a more varus alignment with a mTFA of -1.7 ± 2.9°. The anatomic tibiofemoral angle (aTFA) was 4.8 ± 2.6°, the anatomic lateral distal femoral angle (aLDFA) measured 80.2 ± 2.2°, and the anatomical-mechanical angle (AMA) was 5.4 ± 0.7°. The prevalence of constitutional varus was 18%. The effect of rotation on the rotated scans led to statistically significant differences relative to the 0° measurement for all measurements. These effects may be small, and their clinical importance is unknown.

CONCLUSIONS

This study provides new information on standardized measures of lower extremity alignment and the relationship between discreet axial rotations of the entire lower extremity and these parameters.

Pelvic Tilt Evaluation From Frontal Radiographs: The Validity, Interobserver Reliability and Intraobserver Reproducibility of the Sacro-Femoral-Pubic Parameter

BACKGROUND

The sacro-femoral-pubic (SFP) parameter, calculated using the SFP angle measured on a frontal pelvis radiograph, has previously been shown to have a strong correlation with sagittal pelvic tilt (PT) measured on a lateral x-ray. The purpose of this study is to assess the validity, interobserver reliability and intraobserver reproducibility of the SFP parameter in predicting the sagittal PT.

METHODS

This is a retrospective study of 100 patients with frontal and lateral radiographs of the pelvis. Two observers independently measured the SFP angle on frontal x-ray (midpoint of S1 end plate to centroid of acetabula to upper midpoint of the pubic symphysis) and PT on lateral x-ray (midpoint of sacral plate to the centroid of acetabula to vertical plane). The SFP parameter was defined using the equation: SFP parameter = 75 - SFP angle. The interobserver reliability and intraobserver reproducibility were calculated using interclass correlation coefficient (ICC). Validity of the SFP parameter was calculated using Pearson correlation coefficient.

RESULTS

The intraobserver reproducibility of the SFP parameter was excellent (ICC >0.90) for both observers. The interobserver reliability of all measurements was substantial for the SFP parameter (ICC >0.80) and PT (ICC >0.70). The concurrent validity of the SFP parameter was substantial (r = 0.70).

CONCLUSION

Calculating PT from a frontal radiograph using the equation for the SFP parameter is a valid, reliable, and reproducible formula that may be used to predict sagittal PT.

Biomechanical Consequences of Anterior Femoral Notching in Cruciate-Retaining Versus Posterior-Stabilized Total Knee Arthroplasty

Anterior femoral notching during total knee arthroplasty is a potential risk factor for periprosthetic supracondylar femur fracture. We conducted a study to determine if the design of the femoral implant changes the risk for periprosthetic supracondylar femur fractures after anterior cortical notching. An anterior cortical defect was created in 12 femoral polyurethane models. Six femora were instrumented with cruciate-retaining implants and 6 with posterior-stabilized implants. Each femur was loaded in external rotation along the anatomical axis. Notch depth and distance from anterior cortical notch to implant were recorded before loading, and fracture pattern was recorded after failure. There were no statistically significant differences in notch depth, distance from notch to implant, torsional stiffness, torque at failure, final torque, or fracture pattern between cruciate-retaining and posterior-stabilized femoral component designs. Periprosthetic fracture after anterior femoral notching is independent of the bone removed from the intercondylar notch. After notching, there likely is no significant difference in femoral strength in torsion between cruciate-retaining and posterior-stabilized designs.

Periprosthetic supracondylar femur fracture treated with spanning external fixation

Periprosthetic supracondylar fractures of the femur after total knee arthroplasty represent a devastating complication for the patient and a technical challenge for the surgeon. Treatment is often complicated by advanced patient age, retained cement, and accompanying osteoporosis. We present the case of a 54-year-old woman with a comminuted fracture of the distal femur just above a total knee prosthesis. She had a complex past medical history, including extensive coronary artery disease, morbid obesity, chronic osteoporosis, anemia, diabetes, and rheumatoid arthritis. She was a Jehovah's Witness and thus refused all blood products. Given her medical history, religious preferences, and fracture comminution, a spanning external fixator was used. She completed fracture union with an excellent clinical and radiographic result at 2 years.

Younger age is associated with a higher risk of early periprosthetic joint infection and aseptic mechanical failure after total knee arthroplasty

BACKGROUND

Although early aseptic mechanical failure after total knee arthroplasty has been reported in younger patients, it is unknown whether early revision due to periprosthetic joint infection is more or less frequent in this patient subgroup. The purpose of this study was to determine whether the incidence of early periprosthetic joint infection requiring revision knee surgery is significantly different in patients younger than fifty years of age compared with older patients following primary unilateral total knee arthroplasty.

METHODS

A large population-based study was conducted with use of the California Patient Discharge Database, which allows serial linkage of all discharge data from nonfederal hospitals in the state over time. Patients undergoing primary unilateral total knee arthroplasty during 2005 to 2009 were identified. Principal outcomes were partial or complete revision arthroplasty due to periprosthetic joint infection or due to aseptic mechanical failure within one year. Multivariate analysis included risk adjustment for important demographic and clinical variables. The effect of hospital total knee arthroplasty volume on the outcomes of infection and mechanical failure was analyzed with use of hierarchical modeling.

RESULTS

At one year, 983 (0.82%) of 120,538 primary total knee arthroplasties had undergone revision due to periprosthetic joint infection and 1385 (1.15%) had undergone revision due to aseptic mechanical failure. The cumulative incidence in patients younger than fifty years of age was 1.36% for revision due to periprosthetic joint infection and 3.49% for revision due to aseptic mechanical failure. In risk-adjusted models, the risk of periprosthetic joint infection was 1.8 times higher in patients younger than fifty years of age (odds ratio = 1.81, 95% confidence interval = 1.33 to 2.47) compared with patients sixty-five years of age or older, and the risk of aseptic mechanical failure was 4.7 times higher (odds ratio = 4.66, 95% confidence interval = 3.77 to 5.76). The rate of revision due to infection at hospitals in which a mean of more than 200 total knee arthroplasties were performed per year was lower than the expected (mean) value (p = 0.04).

CONCLUSIONS

Patients younger than fifty years of age had a significantly higher risk of undergoing revision due to periprosthetic joint infection or to aseptic mechanical failure at one year after primary total knee arthroplasty.

Management of incarcerating pincer-type femoroacetabular impingement with hip arthroscopy

This report describes the arthroscopic management of a case of incarcerating pincer-type femoroacetabular impingement. The hip joint had a marked restriction of range of motion and secondary pain as a result of osteophytes wrapping around the femoral head down the femoral neck. The patient was treated with staged bilateral hip arthroscopy. The procedures were initially performed through the peripheral compartment to remove the incarcerating acetabular rim, followed by arthroscopy of the central compartment with acetabuloplasty and femoral head osteochondroplasty. The patient's treatment has led to an excellent clinical and radiographic result at 24 months' follow-up despite an unrelated pelvic fracture sustained in the postoperative period. This technique emphasizes the capabilities of hip arthroscopy in advanced cases of femoroacetabular impingement as an alternative to arthroplasty for patients with healthy articular cartilage.

What is normal femoral head/neck anatomy? An analysis of radial CT reconstructions in adolescents

BACKGROUND

Cam morphology in femoroacetabular impingement has been implicated in the development of osteoarthritis. The alpha angle and femoral head/neck offset are widely used to determine femoral head asphericity. To our knowledge, no study has evaluated the alpha angle circumferentially using three-dimensional imaging in a population of healthy individuals of adolescent age.

QUESTIONS/PURPOSES

We sought to (1) determine normal values for the alpha angle in adolescents, (2) define the location along the neck with the highest alpha angle, and (3) determine normal femoral head and neck radii and femoral head/neck offset.

METHODS

Fifty CT scans from a database of scans obtained for reasons not related to hip pain were studied. The average age of the subjects was 15 years (range, 14-16 years). Alpha angle and femoral head/neck offset were measured circumferentially.

RESULTS

The alpha angle averaged 40.66 ± 4.46 mm for males and 37.77 ± 5.65 mm for females. The alpha angle generally was highest between the 11:40 and 12:40 o'clock and between the 6:00 and 7:40 o'clock positions. The femoral head radius was 24.53 ± 1.74 mm for males and 21.94 ± 1.13 mm for females, and the femoral neck radius was 16.14 ± 2.32 mm for males and 13.82 ± 2.38 mm for females. The mean femoral head/neck offset was 8.39 ± 1.97 mm for males and 8.13 ± 2.27 mm for females.

CONCLUSIONS

In this healthy population of 14- to 16-year-old subjects, the highest alpha angle was at the superior and inferior aspects of the heads rather than at the anterosuperior aspect. This information will provide benchmark values for distinction between normal and abnormal morphologic features of the femoral head.

Surgical treatment of trochanteric and cervical hip fractures in the United States: 2000-2009

The objective of this study was to evaluate the most common treatments performed for hip fractures over the last decade in the United States. The leading treatment for trochanteric fractures was internal fixation, accounting for 96%-98% of surgical treatments each year. For cervical fractures, hemiarthroplasty (HA), total hip arthroplasty (THA), and internal fixation were performed nearly 61%, 5%, and 33% of the time, respectively, each year without any sign of change during the period assessed. The surgical choice for cervical fractures varied greatly by patient age. In 2009, two-thirds of patients younger than 60 years underwent internal fixation while two-thirds of patients 60 years or older underwent HA. Regardless of patient age, HA was performed more often than THA for cervical hip fractures.

Epidemiology of primary hip and knee arthroplasties in Germany: 2004 to 2008

The objective of this study was to describe the trend in utilization of primary joint arthroplasties in Germany. Between 2004 and 2008, the number of total knee arthroplasties (TKAs) increased faster than that of total hip arthroplasties (THAs). In 2008, 159000 primary THAs and 146000 primary TKAs were performed. This represented a 15% increase in THAs and a 33% increase in TKAs compared to 2004. The annual increase in number of surgeries was 4500 for THAs and 9,000 for TKAs. Although older adults remained the main recipients of joint arthroplasties, incidence rate increased faster in non-elderly(18-64 years) compared with elderly (≥65 years) in both THAs and TKAs. Obesity, more strongly associated with TKAs than with THAs, could be a contributor to the recent steeper growth in TKAs in Germany.

Hip fractures in the United States: 2008 nationwide emergency department sample

OBJECTIVE

To evaluate the recent epidemiology of hip fractures in the US.

METHODS

We identified hip fracture cases from the 2008 Nationwide Emergency Department Sample, which contains more than 28 million emergency department (ED) records.

RESULTS

In 2008, approximately 341,000 (95% confidence interval 323,000-358,000) patients visited EDs with hip fractures. Of those, 90% were age >60 years. Between ages 60-85 years, the risk of fracture doubled for every 5- to 6-year increase in age. However, the hip fracture risk increased slowly after age 85 years. The overall trochanteric-to-cervical fracture ratio was nearly 2:1. The risk of trochanteric fracture increased faster with age compared with the risk of cervical fracture. At age 85 years, the rates of trochanteric and cervical fractures (per 100,000) were 1,300 and 700, respectively, among women and 800 and 500, respectively, among men.

CONCLUSION

The slowed growth of hip fracture risk after age 85 years suggests that the eldest old group may have a distinct hip fracture risk. Our study showed that trochanteric fractures were twice as common as cervical fractures. Because trochanteric fractures are more closely related to severe and generalized bone loss than cervical fractures, we hypothesize that the high incidence rate of trochanteric fractures in the US suggests that osteoporosis is a health problem that is linked to hip fracture. In addition to improved safety measures to reduce falls, rigorous preventive treatments of osteoporosis may be needed.

A population-based comparison of the incidence of adverse outcomes after simultaneous-bilateral and staged-bilateral total knee arthroplasty

BACKGROUND

It is unclear whether simultaneous-bilateral total knee arthroplasty is as safe as staged-bilateral arthroplasty is. We are aware of no randomized trials comparing the safety of these surgical strategies. The purpose of this study was to retrospectively compare these two strategies, with use of an intention-to-treat approach for the staged-bilateral arthroplasty cohort.

METHODS

We used linked hospital discharge data to compare the safety of simultaneous-bilateral and staged-bilateral knee arthroplasty procedures performed in California between 1997 and 2007. Estimates were generated to take into account patients who had planned to undergo staged-bilateral arthroplasty but never underwent the second procedure because of death, a major complication, or elective withdrawal. Hierarchical logistic regression modeling was used to adjust the comparisons for patient and hospital characteristics. The principal outcomes of interest were death, a major complication involving the cardiovascular system, and a periprosthetic knee infection or mechanical malfunction requiring revision surgery.

RESULTS

Records were available for 11,445 simultaneous-bilateral arthroplasty procedures and 23,715 staged-bilateral procedures. On the basis of an intermediate estimate of the number of complications that occurred after the first procedure in a staged-bilateral arthroplasty, patients who underwent simultaneous-bilateral arthroplasty had a significantly higher adjusted odds ratio (OR) of myocardial infarction (OR = 1.6, 95% confidence interval [CI] = 1.2 to 2.2) and of pulmonary embolism (OR = 1.4, 95% CI = 1.1 to 1.8), similar odds of death (OR = 1.3, 95% CI = 0.9 to 1.9) and of ischemic stroke (OR = 1.0, 95% CI = 0.6 to 1.6), and significantly lower odds of major joint infection (OR = 0.6, 95% CI = 0.5 to 0.7) and of major mechanical malfunction (OR = 0.7, 95% CI = 0.6 to 0.9) compared with patients who planned to undergo staged-bilateral arthroplasty. The unadjusted thirty-day incidence of death or a coronary event was 3.2 events per thousand patients higher after simultaneous-bilateral arthroplasty than after staged-bilateral arthroplasty, but the one-year incidence of major joint infection or major mechanical malfunction was 10.5 events per thousand lower after simultaneous-bilateral arthroplasty.

CONCLUSIONS

Simultaneous-bilateral total knee arthroplasty was associated with a clinically important reduction in the incidence of periprosthetic joint infection and malfunction within one year after arthroplasty, but it was associated with a moderately higher risk of an adverse cardiovascular outcome within thirty days. If patients who are at higher risk for cardiovascular complications can be identified, simultaneous-bilateral knee arthroplasty may be the preferred surgical strategy for the remaining lower-risk patients.

Intermediate-term radiographic and patient outcomes in revision hip arthroplasty with a modular calcar design and porous plasma coating

This study is a retrospective evaluation of the intermediate-term results of 26 consecutive revision total hip arthroplasties performed with a modular titanium, uncemented femoral component. The average patient age at the time of revision total hip arthroplasty was 72 years, and there were an equal number of males and females. The mean follow-up was 5.7 years (ranging from 4 to 11 years). No re-revision was necessary during this follow-up time. The mean Harris hip score improved significantly (preoperative and postoperative score was 50.7 and 89.6, respectively; P < .001). Postoperatively, Short Form 36 functional scores averaged 67.7 across 9 functional parameters. Our observed low revision rate and favorable patient-reported outcome scores support the continuous use of modular titanium, uncemented femoral components in revision total hip arthroplasty.

Operative risk of staged bilateral knee arthroplasty is underestimated in retrospective studies

To find a safer surgical option, a number of studies have compared postoperative complications after bilateral total knee arthroplasty vs staged total knee arthroplasty (STKA) by contrasting postoperative complications collected retrospectively. However, we believe that a comparison based on retrospective studies could be biased. The purpose of this study was to demonstrate the misclassification bias associated with a retrospective study in comparing operative outcomes. Our analysis indicates that any conclusions based simply on retrospective analysis of subjects who successfully completed STKA is biased because it includes only cases that recovered after the first operation, rather than all of the patients who had planned STKA. In the absence of a prospective study to date, published studies should be interpreted with caution.

Local antibiotic therapy in osteomyelitis

The local delivery of antibiotics in the treatment of osteomyelitis has been used safely and effectively for decades. Multiple methods of drug delivery have been developed for the purposes of both infection treatment and prophylaxis. The mainstay of treatment in this application over the past 20 years has been non-biodegradable polymethylmethacrylate, which has the advantages of excellent elution characteristics and structural support properties. Biodegradable materials such as calcium sulfate and bone graft substitutes have been used more recently for this purpose. Other biodegradable implants, including synthetic polymers, are not yet approved for use but have demonstrated potential in laboratory investigations. Antibiotic-impregnated metal, a recent development, holds great promise in the treatment and prophylaxis of osteomyelitis in the years to come.

Increase in outpatient knee arthroscopy in the United States: a comparison of National Surveys of Ambulatory Surgery, 1996 and 2006

BACKGROUND

This study was proposed to investigate the changes in the utilization of knee arthroscopy in an ambulatory setting over the past decade in the United States as well as its implications.

METHODS

The National Survey of Ambulatory Surgery, last carried out in 1996, was conducted again in 2006 by the Centers for Disease Control and Prevention. We analyzed the cases with procedure coding indicative of knee arthroscopy or anterior cruciate ligament reconstruction. To produce estimates for all arthroscopic procedures on the knee in an ambulatory setting in the United States for each year, we performed a design-based statistical analysis.

RESULTS

The number of arthroscopic procedures on the knee increased 49% between 1996 and 2006. While the number of arthroscopic procedures for knee injury had dramatically increased, arthroscopic procedures for knee osteoarthritis had decreased. In 1996, knee arthroscopies performed in freestanding ambulatory surgery centers comprised only 15% of all orthopaedic procedures, but the proportion increased to 51% in 2006. There was a large increase in knee arthroscopy among middle-aged patients regardless of sex. In 2006, >99% of arthroscopic procedures on the knee were in an outpatient setting. Approximately 984,607 arthroscopic procedures on the knee (95% confidence interval, 895,999 to 1,073,215) were performed in an outpatient setting in 2006. Among those, 127,446 procedures (95% confidence interval, 95,124 to 159,768) were for anterior cruciate ligament reconstruction. Nearly 500,000 arthroscopic procedures were performed for medial or lateral meniscal tears.

CONCLUSIONS

This study revealed that the knee arthroscopy rate in the United States was more than twofold higher than in England or Ontario, Canada, in 2006. Our study found that nearly half of the knee arthroscopic procedures were performed for meniscal tears. Meniscal damage, detected by magnetic resonance imaging, is commonly assumed to be the source of pain and symptoms. Further study is imperative to better define the symptoms, physical findings, and radiographic findings that are predictive of successful arthroscopic treatment.

Failure of interpositional membrane to prevent recurrent arthrofibrosis

Silicone has been used in numerous health care roles, from catheters to finger joint arthroplasties, with proven success. Its use as an interpositional membrane for the prevention of adhesions has been attempted in various anatomic sites with unpredictable results. We present a case report of a patient with recurrent arthrofibrosis requiring multiple operative procedures including manipulations under anesthesia, arthroscopies, and unicompartmental and eventual total knee replacement. After developing stiffness after total knee arthroplasty, the patient received placement of a silicone interpositional membrane with the goal of minimizing scar formation. Arthrofibrosis recurred, and only eventual removal of the membrane and correction of the underlying overstuffed patellofemoral compartment has allowed for maintained functional improvement in motion after 3 years.

Osteochondroma of the femoral neck: a rare cause of sciatic nerve compression

A 39-year-old man presented with weakness and a nonmobile mass in the buttock of 5 months' duration. Hip flexion was limited to 70 degrees. Strength was diminished for both ankle/foot plantar and dorsiflexion. Sensation was decreased on the plantar and dorsal foot. A pedunculated osseous mass measuring 6x4 cm on the posterior femoral neck was seen on plain radiographs and magnetic resonance imaging. Electromyography showed moderate sciatic neuropathy of the peroneal and tibial branches. The patient underwent excision of the tumor through a posterior approach. Due to the risk of weakening the neck, two 7.3-mm cannulated screws were passed percutaneously into the head with fluoroscopic guidance. The final pathological report indicated the tumor was an osteochondroma. At 22-month follow-up, he had full resolution of the neurologic findings. Postoperatively, the patient reported improvement in numbness and tingling in the leg but continued to have moderate buttock pain. Left hip flexion increased to 115 degrees at last follow-up.The importance of protecting the medial femoral circumflex artery during approaches to the hip is paramount. In this case, the tumor arose from the central aspect of the quadratus femoris, with the superior muscle protecting the medial femoral circumflex artery from harm. Although osteochondromas are a rare cause of mass effect, they should be considered in the differential diagnosis of sciatic nerve compression in this anatomical location.

Minimally invasive bone grafting of cysts of the femoral head and acetabulum in femoroacetabular impingement: arthroscopic technique and case presentation

Femoroacetabular impingement (FAI) has been recently established as a risk factor in the development of osteoarthritis of the hip. Intraosseous cysts are commonly seen on imaging of FAI. In most cases these cysts are incidental and do not require specific treatment at the time of surgical treatment of hip impingement. However, in some cases the cysts may mechanically compromise the acetabular rim or femoral neck. We present a technique for treating such cysts with an all-arthroscopic technique using a commercially available bone graft substitute composed of cancellous bone and demineralized bone matrix placed within an arthroscopic cannula for direct delivery into the cysts. This technique may be of benefit to surgeons treating FAI with an all-arthroscopic technique.

Femoral neck exostosis, a manifestation of cam/pincer combined femoroacetabular impingement

We present 2 cases of cam/pincer combined femoroacetabular impingement treated arthroscopically with labral debridement, acetabuloplasty, and femoral head recontouring. In both cases there was essentially no evidence of osteoarthritis of the hip. However, in both cases raised exostoses were evident on the anterolateral femoral neck in the region that commonly comes into contact with the acetabular rim. On the basis of 3-dimensional dynamic reconstructions, we surmise that these exostoses are a direct result of linear contact between the femoral neck and acetabular rim. We recommend that the presence of these exostoses be carefully noted by the arthroscopic hip surgeon and that they be a geographic marker of the zone of contact between the head-neck junction and the acetabular rim and a guide for the area of head osteochondroplasty in combination with appropriate treatment of the acetabular rim.

Closing wedge retrotubercular tibial osteotomy and TKA for posttraumatic osteoarthritis with angular deformity

Posttraumatic osteoarthritis of the knee can be associated with angular deformities and alterations in the joint line as a result of the initial trauma and subsequent surgical procedures. These deformities can be characterized as extra-articular or intra-articular or can involve aspects of both. Conversion to total knee arthroplasty (TKA) may require either a staged or a simultaneous corrective osteotomy to restore the limb alignment and proper knee function. This article describes a closing wedge retrotubercular tibia osteotomy performed concurrently with TKA in an effort to correct an extra-articular varus deformity and to improve the patella tendon height in relation to the reconstructed joint line. A 57-year-old man previously treated for a Schatzker type 6 tibia plateau fracture presented with symptoms of arthritis pain and instability as a result of a varus thrust with weight bearing. Radiographs revealed posttraumatic osteoarthritis, a 35 degrees varus deformity, and patella infera. Maintaining the tibia tubercle continuity with the distal tibia allowed for correction of the varus deformity and improvement in the patella tendon height relative to the joint line. At 5-year follow-up, the patient had osteotomy healing, clinically neutral limb alignment, and improvement in joint line biomechanics with resolution of symptoms of pain and instability.

Minimally invasive management of a floating prosthesis injury with locking plates

Periprosthetic fractures involving a total knee arthroplasty pose a challenging treatment problem with a prevalence of up to 2.5% in the literature (Instr Course Lect 2001;50:379-389). The supracondylar region of the femur is commonly involved, often with minimal available bone in contact with the components. The clinical challenges are particularly more complex in the case of a combined distal femoral and proximal tibial periprosthetic fracture. This injury is considered a "floating prosthesis" injury because of the complete separation of the prosthesis from the remaining skeleton. In this report, a floating prosthesis injury, in combination with a femoral shaft fracture, is treated with 2 locking plates using a minimally invasive technique, with limited blood loss, immediate pain relief after surgery, and successful healing of all fractures with minimal deformity.

Knee fusion using dual platings with the locking compression plate

Knee arthrodesis is often used as a salvage procedure for infected, nonreconstructable total knee arthroplasties. We report 3 cases of infected total knee arthroplasties treated with knee fusion using locking compression plates. After at least 2 years of follow-up, these patients have healed with improvement in both symptoms and mobility.