Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Knee Arthroplasty.

BACKGROUND: Frailty can predict adverse outcomes after various orthopaedic procedures, but is not well-studied in revision total knee arthroplasty (rTKA). We investigated the correlation between the Hospital Frailty Risk Score (HFRS) and post-rTKA outcomes. METHODS: Using the Nationwide Readmissions Database, we identified rTKA patients discharged from January 2017 to November 2019 for the most common diagnoses (mechanical loosening, infection, and instability). Using HFRS, we compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients with multivariate and binomial regressions. The 30-day complication and reoperation rates were compared using univariate analyses. We identified 25,177 mechanical loosening patients, 12,712 infection patients, and 9,458 instability patients. RESULTS: Frail patients had higher rates of 30-day readmission (7.8 versus 3.7% for loosening, 13.5 versus 8.1% for infection, 8.7 versus 3.9% for instability; P < .01), longer length of stay (4.1 versus 2.4 days for loosening, 8.1 versus 4.4 days for infection, 4.9 versus 2.4 days for instability; P < .01), and greater cost ($32,082 versus $27,582 for loosening, $32,898 versus $28,115 for infection, $29,790 versus $24,164 for instability; P < .01). Frail loosening patients had higher 30-day complication (6.8 versus 2.9%, P < .01) and reoperation rates (1.8 versus 1.2%, P = .01). Frail infection patients had higher 30-day complication rates (14.0 versus 8.3%, P < .01). Frail instability patients had higher 30-day complication (8.0 versus 3.5%, P < .01) and reoperation rates (3.2 versus 1.6%, P < .01). CONCLUSIONS: The HFRS may identify patients at risk for adverse events and increased costs after rTKA. Further research is needed to determine causation and mitigate complications and costs.

Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Total Hip Arthroplasty.

BACKGROUND: Frailty has been associated with poor outcomes and higher costs after primary total hip arthroplasty. However, frailty has not been studied in relation to outcomes after revision total hip arthroplasty (rTHA). This study examined the relationship between the Hospital Frailty Risk Score (HFRS), postoperative outcomes, and cost profiles following rTHA. METHODS: In this retrospective cohort study, we identified patients who underwent rTHA from January 2017 to November 2019 in the Nationwide Readmission Database. The 3 most frequently reported diagnosis codes for rTHA were then selected: dislocation; mechanical loosening; and infection. We calculated the HFRS for each patient to determine frailty status. We compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients, using multivariate logistic and negative binomial regressions to adjust for covariates. We identified 36,243 total patients who underwent rTHA. Overall, 15,448 patients had a revision for dislocation, 11,062 for mechanical loosening, and 9,733 for infection. RESULTS: Compared to nonfrail patients, frail patients had higher rates of 30-day readmission, longer length of stay, and higher hospitalization cost. Frail patients had significantly higher rates of 30-day complication and 30-day reoperation. CONCLUSIONS: Frailty, measured using HFRS, is associated with increased postoperative complications and costs after rTHA. The HFRS has the ability to efficiently identify frail patients at-risk for perioperative complications enabling care teams to better focus optimization interventions on this patient cohort.

The Microbiome of Osteoarthritic Hip and Knee Joints: A Prospective Multicenter Investigation.

BACKGROUND: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients. METHODS: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed. RESULTS: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages. CONCLUSIONS: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Intractable Bleeding After Revision Hip Arthroplasty Because of Angiosarcoma: A Report of 2 Cases.

CASE: Two cases of revision total hip arthroplasty (THA) for pseudotumor and infection with persistent postoperative bleeding because of angiosarcoma are presented. After surgery, both patients' health deteriorated because of hypovolemic shock despite transfusion, pressors, embolization, and prothrombotics. Diagnosis was obscure and delayed despite extensive imaging. Standard and computed tomography angiogram were nondiagnostic and did not localize the tumors or bleeding. Repeat surgeries and biopsies requiring special staining ultimately revealed epithelioid angiosarcoma. CONCLUSION: A diagnosis of angiosarcoma was etiologic for persistent postoperative bleeding after revision THA and should be considered in such cases.

Frailty is Associated With Increased Complication, Readmission, and Hospitalization Costs Following Primary Total Knee Arthroplasty.

BACKGROUND: Frailty has been associated with poor postoperative outcomes in various medical conditions and surgical procedures. However, the relationship between frailty and outcomes after primary total knee arthroplasty (TKA) has not been well-described. This study investigated the association of the Hospital Frailty Risk Score (HFRS) with postoperative events and hospitalization costs after primary TKA. METHODS: Using a nationwide readmissions database, we identified 884,479 patients discharged after primary TKA for osteoarthritis between January 2017 and November 2019. HFRS was calculated for each patient to determine frailty status. We used multivariate logistic regressions to evaluate the association of frailty with 30-readmission rate and negative binomial regressions to evaluate lengths of hospital stay and hospitalization costs. The 30-day reoperation and complication rates were compared using chi-square tests. RESULTS: Frailty was associated with increased odds of 30-day readmissions (odds ratio [OR]: 1.89, 95% confidence interval [CI]: 1.82-1.96), longer lengths of stay (OR: 1.43, 95% CI: 1.43-1.44), and higher hospitalization costs (OR: 1.16, 95% CI: 1.16-1.17). Frail patients also had significantly higher rates of 30-day reoperations (0.6 versus 0.4%), surgical complications (0.6 versus 0.4%), medical complications (3.4 versus 1.3%), and other complications (0.9 versus 0.5%) (P < .01). CONCLUSIONS: Frailty, as measured using HFRS, was associated with increased adverse events and health care burdens in patients undergoing TKA. The HFRS could be used to swiftly identify high-risk patients undergoing TKA and to potentially help optimize patients prior to elective TKA. TYPE OF STUDY: Level III retrospective cohort study.

Impact of State Opioid Regulation on Postoperative Opioid Prescribing Patterns for Total Knee Arthroplasty: A Retrospective Analysis.

BACKGROUND: Limited studies have assessed the impact of state regulations on opioid prescribing patterns for patients undergoing total knee arthroplasty (TKA). This study evaluates how Florida House Bill 21 (FL-HB21) affected postoperative opioid prescribing for patients after TKA. METHODS: Institutional review board approval was obtained to retrospectively review all patients who underwent TKA during 3 months of 2017 (pre-law) and 2018 (post-law) by five arthroplasty surgeons in Florida. Prescribed opioid quantity in morphine milligram equivalents (MME), quantity of refills, and number of prescribers were recorded for each patient's 90-day postsurgical episode. The differences between pre-law and post-law prescription data and short-term postoperative pain levels were compared. RESULTS: The average total MME was notably reduced by over 30% for all time periods for the post-law group. The average MME per patient decreased by 169 MME at the time of discharge, by 245 MME during subsequent postoperative visits, and by 414 MME for the 90-day postsurgical episode ( P < 0.001 for all). The quantity of refills was unchanged (1.6 vs. 1.6, P = 0.885). The total number of prescribers per patient for the 90-day postsurgical episode was unchanged (1.31 vs. 1.24 prescribers/patient, P = 0.16). Postoperative pain levels were similar at discharge (3.6 pre-law vs. 3.3 post-law, P = 0.272). DISCUSSION: Restrictive opioid legislation was associated with notably reduced postoperative opioid (MME) prescribed per patient after TKA at the time of discharge and for the entire 90-day postsurgical episode. There was no increase in the number of prescribers or refills required by patients. LEVEL OF EVIDENCE: Level III retrospective cohort.

Total Knee Arthroplasty Complicated by Diffuse Large B-Cell Lymphoma.

A 74-year-old male with a prior left total knee arthroplasty presented with deformity, loosening, pain, and stiffness associated with multiple raised, erythematous, cutaneous nodules about the anterior knee. Workup was concerning for infection, but the skin nodules were atypical. The patient was sent for biopsy which revealed cutaneous diffuse large B-cell lymphoma. The revision surgery was delayed, and the patient underwent chemotherapy/radiation with complete resolution of his lymphoma. He then underwent a successful aseptic revision total knee arthroplasty. Proper identification and treatment of rare cutaneous skin lesions about a prior surgical site can limit morbidity and result in more desirable outcomes.

Total Hip Arthroplasty With Subtrochanteric Osteotomy for Developmental Hip Dysplasia: A Long-term Follow-up Study.

Background: Total hip arthroplasty (THA) for developmental hip dysplasia (DDH) often requires a subtrochanteric shortening derotational osteotomy (SDO) to limit leg lengthening, mitigate risk of peripheral nerve palsy, and reduce excessive femoral anteversion. Few studies exist detailing long-term clinical outcomes and survivorship. The aim of this study is to analyze the long-term outcomes and survivorship of an SDO-THA cohort. Methods: We retrospectively reviewed all patients who underwent cementless THA with femoral osteotomy due to Crowe I-IV DDH between 1991 and 2001. Primary outcome measures included revision surgery for any reason and functional outcome measures using modified Harris Hip scores. Secondary outcome measures included mode of implant failure and radiographic assessment for osteotomy union, polyethylene wear, osteolysis, and implant loosening. Results: Our review resulted in 24 SDO-THA cases in 20 patients with a mean follow-up of 19 years (range, 8-27 years). Overall survivorship was 67%. All 8 failures were treated with acetabular revision at a mean time to revision of 11 years (range, 1-25 years). Of the failures, there were 5 cases due to polyethylene wear (62.5%), 2 cases due to acetabular loosening (25%), and 1 case due to recurrent instability (12.5%). The mean postoperative modified Harris Hip score was 76 (range, 52-91) with long-term improvement of 43 points maintained (P < .001). Conclusions: THA with SDO can produce durable long-term outcomes for the patient with DDH. It is important to consider some common reasons for revision, namely polyethylene wear and osteolysis, acetabular loosening, and recurrent acetabular dislocations.

An Enhanced Understanding of Culture-Negative Periprosthetic Joint Infection with Next-Generation Sequencing: A Multicenter Study.

BACKGROUND: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI. METHODS: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis. RESULTS: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections. CONCLUSIONS: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial. LEVEL OF EVIDENCE: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Efficacy and Durability of Opioid Restrictive State Legislation Two Years After Implementation for Total Knee Arthroplasty.

BACKGROUND: To curtail the U.S. opioid crisis, many states have instituted regulations that mandate time and/or dosage limits for opioid prescriptions. This study evaluates the impact of one such law, Florida House Bill 21, on postoperative opioid prescribing patterns for patients undergoing total knee arthroplasty (TKA) and the durability of the law's impact over time. METHODS: All patients who underwent TKA at a single institution during the same three-month period in 2017 (pre-law), 2018 (post-law), and 2020 (2 years post-law) were identified. Outcomes and measures included: prescribed morphine milligram equivalents (MME) at discharge and for the 90-day surgical episode, refill quantity with associated MME, and quantity of opioid prescribers. Patients with established chronic pain or those who underwent contralateral TKA during the 90-day window were excluded. Data was compared using a one-way analysis of variance. Significance was set at alpha <0.05. RESULTS: The average MME of filled opioid prescriptions per patient during the 90-day post-surgical episode decreased from 1310 MME in 2017 to 891 MME in 2018 (P < .001). The average MME in 2020 was 814 MME, which was significantly lower than the average in 2017 (P < .001), and statistically stable compared to the average in 2018 (P = .215). CONCLUSION: Restrictive opioid state policy implementation was associated with reduced overall MME prescription to patients undergoing TKA at discharge and for the 90-day surgical episode. There was no increase in the number of opioid refills or opioid prescribers. Durable change and continued improvement were observed 2 years after implementation of law.

A Short-Term Multicenter Analysis of Radiolucent Lines in a Single Uncemented Rotating Platform Implant for Total Knee Arthroplasty.

Background: Uncemented total knee arthroplasty is increasing as a potential solution for aseptic loosening via biologic fixation and to increase operative efficiency. However, postoperative radiolucent lines (RLLs) remain a concern for some clinicians. We report on a multicenter analysis of these RLLs over a 2-year period to identify their incidence, progression, and clinical significance. Material and methods: Institutional review board approval was obtained for this retrospective, multicenter case series. A total of 312 patients treated with a single cruciate-retaining, fully porous coated femoral and tibial component design were included in the study. All patients were evaluated clinically and radiographically in the early postoperative period and at final follow-up (average 2.0 years). Average age of the study group was 58.2 years, and average body mass index was 30.7. Of the total, 66% were male, and 34% were female. Two independent surgeons evaluated the radiographs at the initial postoperative visit and at the most recent follow-up for RLLs. Knee Society Scores and range of motion (ROM) were collected at each visit. Results: We identified RLLs in 25% of patients. All RLLs were less than 1 mm in size and located at the periphery of the tibial implant. None of the RLLs were progressive. At the final follow-up, compared with early postoperative imaging, no new RLLs were identified. Average ROM in flexion was 124 degrees, and the average Knee Society Scores at the most recent clinical follow-up was 96. Conclusion: RLLs are commonly seen following cementless TKA, most commonly underneath the tibial tray. Based on this data set, there does not appear to be progression of these RLLs with time, and they do not appear to have an effect on ROM or clinical outcome at 2 years.

Is it Safe to Continue Clopidogrel in Elective Hip and Knee Arthroplasty?

BACKGROUND: No evidence-based guidelines exist for the perioperative use of clopidogrel in elective hip and knee arthroplasty patients. This study compares the preoperative, intraoperative, and postoperative outcomes of total hip and knee arthroplasty in patients maintained on clopidogrel and with patients whose clopidogrel was held before surgery. METHODS: We retrospectively identified 158 patients taking clopidogrel before undergoing elective total hip or knee arthroplasty. Patients were stratified for having clopidogrel held or continued, based on the interval between latest dose and date of surgery. The primary end points were receipt of transfusion and readmission within 90 days of surgery. Secondary end points were the incidence of complications such as bleeding, infection, re-operation, and major cardiac or neurologic events such as myocardial infarction or stroke during the 90-day postoperative period. RESULTS: The two cohorts had similar demographics. Patients who continued clopidogrel were more likely to receive a blood transfusion postoperatively (9.1% vs 0%, P = .005), but there was no difference in wound drainage (P = .65), wound infection (P = .24), readmission (P = .74), major complications (P = .64), length of stay (P = .70), or mortality (P = .42). Patients who continued clopidogrel before surgery were more likely to have received general anesthesia (P < .001) per anesthesia protocol, however, three such patients did receive spinal anesthesia without any complications. With cementless implants, blood loss was not different between clopidogrel groups. CONCLUSION: Patients undergoing elective total hip and knee arthroplasty may be safely maintained on clopidogrel without an increased risk of wound complications, infections, length of stay, readmission, reoperation, major medical complications, or mortality. Further prospective research is warranted to confirm the effects of continuing clopidogrel in patients undergoing elective hip and knee arthroplasty.

Complex Total Hip Arthroplasty in a Patient with Klippel-Trénaunay Syndrome: A Case Report.

CASE: Klippel-Trénaunay syndrome (KTS) carries manifestations including skeletal dysplasia and prominent vascular malformations. This report details a case of hip dysplasia in the setting of KTS treated with total hip arthroplasty (THA) requiring preoperative embolization, intraoperative angiography for placement of an iliac artery occlusive balloon, and modular hip arthroplasty components for femoral and acetabular dysplasia. Perioperatively, the patient rehabilitated well and was walking painlessly and unassisted at 3 and 12 months postoperatively. CONCLUSION: Successful THA for dysplasia and degenerative changes associated with KTS is possible but requires a complex multidisciplinary perioperative approach.

Comparison of Cruciate-Sacrificing vs Posterior-Stabilized Total Knee Replacement Using a Contemporary Total Knee System.

BACKGROUND: The use of highly conforming polyethylene tibial inserts in cruciate-retaining total knee arthroplasty (TKA) often requires posterior cruciate ligament (PCL) release/sacrifice for balancing (CS TKA). The CS TKA relies on the posterior capsule, collateral ligaments, and articular conformity without a cam or post to achieve stability. Using prospectively collected data we compared clinical outcomes of CS TKA to posterior-stabilized (PS) TKA utilizing a contemporary TKA system. METHODS: Sixty-nine consecutive CS TKAs were compared to 45 consecutive PS TKAs at 2-year minimum follow-up. CS knees were balanced with the PCL released. Preoperative/postoperative range of motion (ROM), Knee Society Scores (KSS), stair function, and squatting ROM were analyzed. RESULTS: At minimum 2-year follow up, CS and PS TKA demonstrated significant improvement in ROM (P < .001), KSS (Pain, P < .001; Function, P < .001), and KSS stair function (P < .001), with no revisions. There was no difference in preoperative to postoperative improvements for passive knee ROM (10° (0°-20°) vs 13° (5°-25°); P = .16), KSS Pain (34 (21-42) vs 38 (24-46); P = .22), KSS Function (35 (30-50) vs 35 (18-50); P = .34), and KSS stair function (10 (10-20) vs 10 (0-20); P = .37) for CS and PS TKA, respectively. CS TKA had higher squatting ROM (P = .02) at minimum 2-year follow-up compared to PS TKA. CONCLUSION: Both PS and CS TKA provided significant improvement in clinical outcomes, with no differences in passive ROM, KSS, or stair function postoperatively. Our data support that with proper articular conformity and balancing, cruciate-retaining TKA in a PCL-deficient knee (CS TKA) is appropriate. This may be design specific and further prospective randomized studies are needed to corroborate these findings.

Evidence-Supported HBO Therapy in Femoral Head Necrosis: A Systematic Review and Meta-Analysis.

Although many studies have shown that hyperbaric oxygen (HBO) therapy can significantly improve symptoms and quality of life of patients affected by femoral head necrosis, this therapy is not worldwide approved yet. This meta-analysis was performed to evaluate its clinical effect. Relevant studies published before May 2020 were systematically searched using terms related to HBO and femoral head necrosis. Fixed and random-effects models were used to estimate the odds ratio (OR) with 95% confidence intervals (CI). Subgroup analyses and publication bias tests were carried out to explore potential study heterogeneity and bias. Ten studies involving 353 controls and 368 HBO-treated cases were included, most of which were conducted on Asian population. The clinical effect in the HBO therapy group was 3.84 times higher than in the control group (OR = 3.84, 95% CI (2.10, 7.02), p < 0.00001). Subgroup analyses showed that the clinical effect of HBO therapy was statistically significant in the Asian subpopulation which represented most of the subjects (OR = 3.53, 95% CI (1.87, 6.64), p < 0.00001), but not in the non-Asian subpopulation, probably because of insufficient numerosity (OR = 7.41, 95% CI (0.73, 75.71), p = 0.09). The results of this meta-analysis suggest that patients with femoral head necrosis treated with HBO therapy can achieve a significant clinical improvement.

Practical Surgical Techniques for Revision Total Hip Arthroplasty.

Although total hip arthroplasty is an extremely successful procedure, the continual increase in the number of total hip arthroplasties that are performed is associated with the substantial burden of revision total hip arthroplasty. Modes of total hip arthroplasty failure include instability, aseptic loosening, infection, periprosthetic fracture, hardware failure, and component wear, all of which are indications for revision total hip arthroplasty. Surgeons must have a sound preoperative revision total hip arthroplasty plan and must be familiar with a variety of component removal and exposure techniques, such as the extended trochanteric osteotomy. Alternative surgical plan(s) and extra implants for reconstruction on both the acetabular and femoral sides should be available in anticipation of unexpected findings. Component removal and exposure techniques can be refined to avoid complications and achieve a successful outcome in patients who undergo revision total hip arthroplasty.

Complete Eradication of Biofilm From Orthopedic Materials.

BACKGROUND: Interest exists in finding alternatives to current management strategies in periprosthetic joint infections, which typically include a 2-stage revision with placement of an antibiotic spacer and delayed placement of a new implant. We studied the efficacy of autoclaving, ultrasonication, and mechanical scrubbing for sterilization and biofilm eradication on infected cobalt-chrome discs. METHODS: Strains of Staphylococcus aureus MRSA252 or Staphylococcus epidermidis RP62A were grown on the discs. For each strain, discs were divided into 5 groups (5 discs each) and exposed to several sterilization and biofilm eradication treatments: (1) autoclave, (2) autoclave + sonication, (3) autoclave + saline scrub, (4) autoclave + 4% chlorhexidine (CHC) scrub, and (5) autoclave + sonication + CHC scrub. Sterilization and biofilm eradication were quantified with crystal violet assays and scanning electron microscopy. RESULTS: Relative to nontreated controls, autoclaving alone reduced biofilm load by 33.9% and 54.7% for MRSA252 and RP62A strains, respectively. Biofilm removal was maximized with the combined treatment of autoclaving and CHC scrub for MRSA252 (100%) and RP62A (99.5%). The addition of sonication between autoclaving and CHC scrubbing resulted in no statistically significant improvement in biofilm removal. High-resolution scanning electron microscopy revealed no cells or biofilm for this combined treatment. CONCLUSION: Using 2 commonly encountered bacterial strains in periprosthetic joint infection, infected cobalt-chrome discs were sterilized and eradicated of residual biofilm with a combination of autoclaving and CHC scrubbing.

Knee strength retention and analgesia with continuous perineural fentanyl infusion after total knee replacement: randomized controlled trial.

PURPOSE: Despite providing adequate pain relief, a femoral nerve block can induce postoperative muscle weakness after total knee arthoplasty (TKA). Fentanyl has been shown to have peripheral effects but has not been used as a perineural infusate alone after TKA. METHODS: Sixty patients scheduled for TKA were randomized to one of three blinded groups: a continuous 24 h infusion of either fentanyl 3 µg/ml, ropivacaine 0.1%, or 0.9% normal saline through a femoral nerve sheath catheter at 10 ml/h. The main outcome was maximum voluntary isometric contraction (MVIC) in the quadriceps femoris (knee extension), measured by a handheld dynamometer (Nm/kg). Other variables assessed were preoperative and postoperative visual analog scale (VAS) scores, hamstrings MVIC (knee flexion), active range of motion of the operative knee, distance ambulated, incidence of knee buckling, supplemental morphine usage, postoperative side effects, and serum fentanyl levels. RESULTS: Quadriceps MVIC values were significantly greater in the fentanyl group compared to the group that received ropivacaine (median values, 0.08 vs. 0.03 Nm/kg; p = 0.028). The incidence of postoperative knee buckling upon ambulation was higher in the ropivacaine group compared to the fentanyl group, although not statistically significant (40% vs. 15 %, respectively; p = 0.077). VAS scores while ambulating were not significantly different between the fentanyl group and the ropivacaine group (p = 0.270). Postoperative morphine consumption, nausea and vomiting, and resting VAS scores were similar among the three groups. CONCLUSIONS: A continuous perineural infusion of fentanyl produced greater strength retention than ropivacaine post-TKA.

Failure analysis of knee arthrodesis with the WichitaFusion Nail.

Arthrodesis is a salvage procedure for failed total knee arthroplasty with the intent to create a stable, pain-free limb on which to ambulate or transfer. For many patients, the alternative to arthrodesis may be an above-knee amputation. Available techniques for knee arthrodesis include compression plating, external fixators, and intramedullary fixation. The purpose of this study was to report the knee fusion rate of consecutive patients at 1 institution using an intramedullary fusion nail and to identify patient risk factors for fusion failure. Between November 1998 and November 2008, twenty-eight patients undergoing knee arthrodesis with an average follow-up of 18 months (range, 3-64 months) were retrospectively studied. Demographic information, presence of fusion, clinical function, pain level, and bone defect data were collected and analyzed. Eighty-two percent (23/28) of patients had radiographic evidence of successful fusion with an average time to fusion of 21 weeks (range, 10-58 weeks). When examining patient variables that could correlate with fusion rates, patients with an Anderson Orthopaedic Research Institute type 3 femoral or type 3 tibial defect had a statistically significant lower fusion rate. The intramedullary fusion nail is an effective device for knee arthrodesis that offers ease of insertion through the knee wound with the advantages of initial bone compression and rigid fixation. Although the use of intramedullary fusion nails leads to a high fusion rate, significant bone deficiency limits successful fusion.

Risk factors for soft tissue knee injuries in active duty U.S. Army soldiers, 2000-2005.

BACKGROUND: There is a scarcity of analytic research on active duty Army (ADA) knee injuries (KI), such as soft tissue knee injuries (STKI), which are the predominant ADA KI pattern. PURPOSE: To quantify the independent adjusted association of significant ADA STKI risk factors, 2000-2005. MATERIALS/METHODS: Using the Total Army Injury and Health Outcomes Database, we (1) captured absolute STKI numbers and rates (N = 83,323) and (2) developed regression models to determine significant STKI risk factors. Models included STKI overall and subcategories: meniscus, patella, anterior/posterior cruciate ligament, and medial/lateral cruciate ligament. RESULTS: Eight risk factors significantly increased STKI. They are: (1) prior KI (within 2 years) (odds ratio [OR] 9.83, 95% confidence interval [CI] 9.67-10.00); (2) increasing length of service (OR 1.83, 95% CI 1.76-1.90); (3) increasing age (OR 1.57, 95% CI 1.50-1.65); (4) prior deployment (OR 1.39, 95% CI 1.36-1.41); (5) prior ankle injury (OR 1.16, 95% CI 1.14-1.19); (6) Infantry occupation (OR 1.12, 95% CI 1.04-1.21); (7) marital status (OR 1.10, 95% CI 1.08-1.12); (8) and prior hip injury (OR 1.08, 95% CI 1.03-1.12). MAJOR CONCLUSION: Soldiers with a prior KI have nearly a 10-fold increased relative risk of developing a subsequent STKI.