Michael J. Taunton

The Fate of Acute Methicillin-Resistant Staphylococcus aureus Periprosthetic Knee Infections Treated by Open Debridement and Retention of Components

The success of open irrigation and debridement with component retention (ODCR) for acute periprosthetic knee joint infection varies widely. The species and virulence of the infecting organism have been shown to influence outcome. This multicenter, retrospective study identified 19 cases of acute periprosthetic methicillin-resistant Staphylococcus aureus (MRSA) knee infections managed by ODCR and at least 4 weeks of postoperative intravenous vancomycin therapy. At minimum follow-up of 2 years, the treatment failed to eradicate the infection in 16 cases (84% failure rate). Of those 16 failures, 13 patients required a 2-stage exchange arthroplasty, 2 patients required repeat incision and debridement with antibiotic suppression, and 1 patient died of MRSA sepsis. In addition, a systematic review of the literature revealed failure to eradicate infection in 10 of 13 patients managed with a similar protocol. The total success rate of ODCR in acute periprosthetic MRSA knee infection was 18%.

Total shoulder arthroplasty with a metal-backed, bone-ingrowth glenoid component: Medium to long-term results

BACKGROUND Loosening of a cemented glenoid component is an important cause of failure in shoulder arthroplasty. This study was developed to examine the outcome of patients managed with a metal-backed, bone-ingrowth glenoid component as an alternative to a cemented component. METHODS The study group included eighty-three total shoulder arthroplasties with a metal-backed, bone-ingrowth glenoid component performed between 1989 and 1994. Seventy-four shoulders had a diagnosis of primary osteoarthritis, and nine shoulders had other diagnoses. All patients were followed radiographically and clinically for a minimum of two years or until the time of revision surgery. Kaplan-Meier survival estimates were performed with revision and/or radiographic failure as the end points. RESULTS The mean clinical follow-up was 9.5 years, and the mean radiographic follow-up was 7.1 years. Pain ratings (on a scale of 1 to 5) decreased from a mean of 4.7 preoperatively to 2.0 postoperatively. The mean range of motion in active elevation increased from 102 degrees preoperatively to 135 degrees postoperatively; the mean external rotation increased from 27 degrees to 56 degrees . Glenohumeral joint instability developed in fourteen shoulders. Radiographic changes consistent with glenoid component loosening were present in thirty-three shoulders. Polyethylene wear with metal wear of the glenoid component was noted in twenty-one shoulders, and humeral component loosening was seen in fifteen shoulders. Revision procedures were performed in twenty-six shoulders. There were no identifiable patient, disease, or surgical characteristics associated with failure, either clinically or radiographically. The five-year survival estimate free of revision or radiographic failure was 79.9% (95% confidence interval, 71.6% to 89.3%), and the ten-year survival estimate was 51.9% (95% confidence interval, 41.0% to 65.8%). CONCLUSIONS The high rate of failure of total shoulder arthroplasties performed with this metal-backed, bone-ingrowth glenoid component raises concerns as to its use, and perhaps the use of other types of metal-backed components, in shoulder arthroplasty, other than for special situations. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Direct Anterior Total Hip Arthroplasty Yields More Rapid Voluntary Cessation of All Walking Aids: A Prospective, Randomized Clinical Trial

This study sought to prospectively examine the clinical and radiographic differences between direct anterior (DA-THA) and mini-posterior approach total hip arthroplasty (MPA-THA). Fifty-four patients were prospectively randomized to either MPA or DA-THA. Patient recorded diaries were collected. Radiographs were reviewed. SF-36, WOMAC and HHS scores were tabulated. Time to ambulation without any assistive device favored DA-THA (22 vs. 28 days, P=0.04). Three week SF mental scores favored MPA-THA (60.66 vs. 58.43, P=0.01). In a randomized prospective trial, patients undergoing DA-THA voluntarily quit use of all walking aids on average 6 days earlier than patients with a MPA-THA. Little additional clinical or radiographic benefit was seen between the cohorts.

Bariatric surgery does not improve outcomes in patients undergoing primary total knee arthroplasty

Bariatric surgery has been advocated as a means of reducing body mass index (BMI) and the risks associated with total knee arthroplasty (TKA). However, this has not been proved clinically. In order to determine the impact of bariatric surgery on the outcome of TKA, we identified a cohort of 91 TKAs that were performed in patients who had undergone bariatric surgery (bariatric cohort). These were matched with two separate cohorts of patients who had not undergone bariatric surgery. One was matched 1:1 with those with a higher pre-bariatric BMI (high BMI group), and the other was matched 1:2 based on those with a lower pre-TKA BMI (low BMI group). In the bariatric group, the mean BMI before bariatric surgery was 51.1 kg/m(2) (37 to 72), which improved to 37.3 kg/m(2) (24 to 59) at the time of TKA. Patients in the bariatric group had a higher risk of, and worse survival free of, re-operation (hazard ratio (HR) 2.6; 95% confidence interval (CI) 1.2 to 6.2; p = 0.02) compared with the high BMI group. Furthermore, the bariatric group had a higher risk of, and worse survival free of re-operation (HR 2.4; 95% CI 1.2 to 3.3; p = 0.2) and revision (HR 2.2; 95% CI 1.1 to 6.5; p = 0.04) compared with the low BMI group. While bariatric surgery reduced the BMI in our patients, more analysis is needed before recommending bariatric surgery before TKA in obese patients.

Seronegative infections in hip and knee arthroplasty: periprosthetic infections with normal erythrocyte sedimentation rate and C-reactive protein level

The aim of our study was to describe the characteristics, treatment, and outcomes of patients with periprosthetic joint infection (PJI) and normal inflammatory markers after total knee arthroplasty (TKA) and total hip arthroplasty (THA). In total 538 TKAs and 414 THAs underwent surgical treatment for PJI and met the inclusion criteria. Pre-operative erythrocyte sedimentation rate (ESR) and C-reactive protein level (CRP) were reviewed to identify the seronegative cohort. An age- and gender-matched cohort was identified from the remaining patients for comparison. Overall, 4% of confirmed infections were seronegative (21 TKA and 17 THA). Of those who underwent pre-operative aspiration, cultures were positive in 76% of TKAs (n = 13) and 64% of THAs (n = 7). Cell count and differential were suggestive of infection in 85% of TKA (n = 11) and all THA aspirates (n = 5). The most common organism was coagulase-negative Staphylococcus. Seronegative infections were associated with a lower aspirate cell count and a lower incidence of Staphylococcus aureus infection. Two-stage revision was performed in 35 cases (95%). At a mean of five years (14 to 162 months) following revision, re-operation for infection occurred in two TKAs, and one THA. From our study we estimate around 4% of patients with PJI may present with normal ESR and CRP. When performed, pre-operative aspirate is useful in delivering a definitive diagnosis. When treated, similar outcomes can be obtained compared with patients with positive serology.

Diagnosis of adverse local tissue reactions following metal-on-metal hip arthroplasty

Metal-on-metal (MOM) bearing surfaces in hip arthroplasty have distinct advantages that led to the increase in popularity in North America in the early 2000s. However, with their increased use, concerns such as local cytotoxicity and hypersensitivity reactions leading to soft tissue damage and cystic mass formation (known collectively as adverse local tissue reactions (ALTR)) became apparent. The clinical presentation of ALTR is highly variable. The diagnosis of ALTR in MOM articulations in hip arthroplasty can be challenging and a combination of clinical presentation, physical examination, implant track record, component positioning, serum metal ion levels, cross-sectional imaging, histopathologic analysis, and consideration of alternative diagnoses are essential.

Long term outcomes of cemented endoprosthetic reconstruction for periarticular tumors of the distal femur

BACKGROUND In order to achieve an oncological margin during limb salvage surgery for tumors of the distal femur, part or the entire knee joint is frequently sacrificed. Endoprosthetics make limb salvage possible through restoration of a functional extremity. Currently there remains a paucity of data concerning their long-term outcomes and associated risk factors for failure. METHODS We identified 152 patients who underwent an endoprosthetic reconstruction for an oncological process of the distal femur between 1972 and 2013. The mean follow-up was 10years. Mean age and body mass index (BMI) were 39years and 25.8 respectively. The most common pathology was osteosarcoma (n=78, 48%). Outcomes were compared to a control group of 20,643 patients undergoing total knee arthroplasty (TKA) for degenerative joint disease (DJD) during the same time period. RESULTS The mean five-, 10-, 15-, 20-, and 25-year revision-free survival for an endoprosthesis was 76%, 63%, 51%, 36%, and 28%. Compared to the five-, 10-, 15-, 20-, and 25-year survival of 95%, 90%, 82%, 74%, and 67% for control TKAs (p<0.0001 at all-time points). Overall limb survival was 93%, with 11 patients undergoing amputation. There was no difference in implant survival comparing modular and custom endoprostheses. CONCLUSION The results of this study show that given the complexity of these operations, the rate of revision surgery following endoprosthetic replacement is high. Nevertheless, the use of these modular reconstructions leads to a high rate of limb salvage (93%) over a 25-year period at our institution. LEVEL OF EVIDENCE Level III.

Insulin Dependence Increases the Risk of Failure After Total Knee Arthroplasty in Morbidly Obese Patients

UNLABELLED The aims of this study were to compare the outcomes between nondiabetic (n=1284), type II diabetic (n=530), and insulin-dependent type II diabetic (n=164) morbidly obese (body mass index ≥40 kg/m(2)) patients undergoing primary total knee arthroplasty at 6-year follow-up. Patients with type II diabetes mellitus (DM) had similar outcomes when compared with non-DM patients. However, patients with insulin dependence had an increased risk of reoperation (hazard ratio [HR], 1.8; P=.005), revision (HR, 2; P=.02), and periprosthetic joint infection (HR, 2.1; P=.03), as well as decreased 10-year implant survivorship (84% vs 92%; P=.01) when compared to non-DM patients. Prospective studies should further evaluate outcomes and optimization measures within this population. LEVEL OF EVIDENCE Level III-prognostic study.

A Three-arm Randomized Clinical Trial Comparing Continuous Femoral Plus Single-injection Sciatic Peripheral Nerve Blocks versus Periarticular Injection with Ropivacaine or Liposomal Bupivacaine for Patients Undergoing Total Knee Arthroplasty

Background: Multimodal analgesia is standard practice for total knee arthroplasty; however, the role of regional techniques in improved perioperative outcomes remains unknown. The authors hypothesized that peripheral nerve blockade would result in lower pain scores and opioid consumption than two competing periarticular injection solutions. Methods: This three-arm, nonblinded trial randomized 165 adults undergoing unilateral primary total knee arthroplasty to receive (1) femoral catheter plus sciatic nerve blocks, (2) ropivacaine-based periarticular injection, or (3) liposomal bupivacaine-based periarticular injection. Primary outcome was maximal pain during postoperative day 1 (0 to 10, numerical pain rating scale) in intention-to-treat analysis. Additional outcomes included pain scores and opioid consumption for postoperative days 0 to 2 and 3 months. Results: One hundred fifty-seven study patients received peripheral nerve block (n = 50), ropivacaine (n = 55), or liposomal bupivacaine (n = 52) and reported median maximal pain scores on postoperative day 1 of 3, 4, and 4.5 and on postoperative day 0 of 1, 4, and 5, respectively (average pain scores for postoperative day 0: 0.6, 1.7, and 2.4 and postoperative day 1: 2.5, 3.5, and 3.7). Postoperative day 1 median maximal pain scores were significantly lower for peripheral nerve blockade compared to liposomal bupivacaine-based periarticular injection (P = 0.016; Hodges–Lehmann median difference [95% CI] = −1 [−2 to 0]). After postanesthesia care unit discharge, postoperative day 0 median maximal and average pain scores were significantly lower for peripheral nerve block compared to both periarticular injections (ropivacaine: maximal −2 [−3 to −1]; P < 0.001; average −0.8 [−1.3 to −0.2]; P = 0.003; and liposomal bupivacaine: maximal −3 [−4 to −2]; P < 0.001; average −1.4 [−2.0 to −0.8]; P < 0.001). Conclusions: Ropivacaine-based periarticular injections provide pain control comparable on postoperative days 1 and 2 to a femoral catheter and single-injection sciatic nerve block. This study did not demonstrate an advantage of liposomal bupivacaine over ropivacaine in periarticular injections for total knee arthroplasty.

No Correlation Between Serum Markers and Early Functional Outcome After Contemporary THA

BackgroundSerum markers of inflammation and muscle damage have shown clinical utility in some areas of medicine, but their value in determining the invasiveness or in predicting the early functional outcomes after total hip arthroplasty (THA) has not been demonstrated.Questions/purposes(1) Do serum markers of inflammation/muscle damage predict pain or early functional outcomes after contemporary THA performed through a direct anterior or miniposterior approach? (2) Do early functional outcomes as measured by in-hospital outcomes and clinical milestones differ between a contemporary direct anterior and miniposterior approach for THA?MethodsBetween August 31, 2013, and September 1, 2014, all patients presenting as candidates for THA at our institution who had not already had preoperative blood draws (161) were recruited for this study. Forty-two patients failed these exclusion criteria, eight patients declined enrollment, and 11 were consented but did not complete the required preoperative blood tests. Recruitment stopped when 50 patients had been enrolled in both the direct anterior group and the miniposterior group (2n = 100) based on a priori power analysis. One high-volume surgeon performed all of the direct anterior approaches and three high-volume surgeons performed the miniposterior approaches. Groups did not differ with the numbers available in mean age (63 years; SD 10; range, 35–86 years), sex (52% female), or mean body mass index (mean 31 kg/m2; SD 7 kg/m2; range, 20–73 kg/m2). Serum markers measured including hemoglobin, hematocrit, myoglobin, creatine kinase (CK), C-reactive protein, interleukin-6, and tumor necrosis factor-α were collected at the preoperative clinic visit and on postoperative days 1 and 2 and compared with operative details, in-hospital complications, therapy progress, pain scores, and functional results from a milestone diary. Functional results evaluated included time to discontinue all narcotics and gait aids, independence with activities of daily living, return to driving a motor vehicle, and return to work.ResultsSerum markers after contemporary THA were not correlated with early functional outcomes either in-hospital or postdischarge. Specifically, no serum marker was predictive of the time to discontinue gait aids or narcotics, return to driving, climb stairs, or independence in activities of daily living (all p > 0.08). The patients receiving the direct anterior approach did have lesser elevations of CK levels than the patients undergoing the miniposterior approach (436 ± 312 [direct anterior {DA}] versus 1071 ± 459 [miniposterior {MP}], difference in means: −635; 95% confidence interval [CI], −809 to −462; p < 0.001), myoglobin levels (168 ± 114 [DA] versus 378 ± 151 [MP], difference in means: −210, 95% CI, −269 to −151; p < 0.001), C-reactive protein (79 ± 57 [DA] versus 124 ± 58 [MP], difference in means: −46, 95% CI, −71 to −21; p < 0.001), and interleukin-6 (45 ± 34 [DA] versus 80 ± 53 [MP], difference in means: −35, 95% CI, −54 to −16; p < 0.001), but not in other serum markers. In the hospital, patients undergoing the direct anterior approach ambulated 35 steps farther with physical therapy (178 feet DA versus 142 feet MP, p < 0.01, difference in means: 35, 95% CI, 9–62; p = 0.009) and had visual analog scale pain scores 1.1 less (4.8 DA versus 5.9 MP, difference in means: −1.1, 95% CI, 2.0 to −0.2; p = 0.02) than patients undergoing the miniposterior approach. There were no differences between approaches in other in-hospital outcomes or in posthospital clinical milestones.ConclusionsSerum markers including CK, myoglobin, C-reactive protein, interleukin-6, and tumor necrosis factor-α did not predict early pain/function after contemporary THA approaches. Although lesser elevations in myoglobin, CK, C-reactive protein, and interleukin-6 were found after direct anterior THA, that difference was not clinically meaningful. Further reporting of serum biomarkers as a measure of physiological burden after orthopaedic surgical procedures should be viewed as suspect until clear linear or threshold values are established.Level of EvidenceLevel III, diagnostic study.