Extensor mechanism allograft reconstruction for extensor mechanism failure following total knee arthroplasty.

Background: Extensor mechanism disruption following total knee arthroplasty is a rare but devastating complication. The purpose of this study was to report our experience with extensor mechanism allograft reconstruction for chronic extensor mechanism failure.

Methods: Fifty consecutive extensor mechanism allograft reconstructions were performed in forty-seven patients with a mean age of 67.

Intraprosthetic Dislocation of Dual-Mobility Bearings Associated with Closed Reduction: A Report of Two Cases.

Case: We present two patients with dual-mobility total hip arthroplasty components who underwent closed reduction of posterior dislocations with conscious sedation in the emergency room. Following closed reduction, both patients had immediate pain, clicking, and grinding of the hip. Radiographs identified intraprosthetic dislocation of the dual-mobility components, and revision surgery was required.

Metal ion levels in maternal and placental blood after metal-on-metal total hip arthroplasty.

There is concern regarding elevated metal ion levels in the blood during pregnancy and the potential fetal effects in women with metal-on-metal (MOM) implants. We obtained maternal and umbilical cord blood samples from 3 patients with a MOM hip arthroplasty and 7 control subjects without any metallic implants. Serum metal ion levels including chromium, cobalt, titanium, and nickel were tested using high-resolution sector-field inductively-coupled plasma-mass spectrometry.

The impact of total joint arthroplasty on sexual function in young, active patients.

There is limited information regarding sexual function following total hip (THA) and knee arthroplasty (TKA). A multicenter study of 806 THA, 542 TKA, and 181 control patients less than 60 years of age was conducted using an independent survey center to question subjects about their sexual function. Only 1.

Periprosthetic joint infection: modern aspects of prevention, diagnosis, and treatment.

Periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) is a devastating complication. Despite improvements in our understanding of PJI, the prevalence of this complication has not decreased in recent years, with various authors reporting rates of 1 to 2% after primary TJA and up to 7% following revision TJA. While the volume of publications, symposiums, and presentations on PJI is vast, controversy still remains regarding the prevention, diagnosis, and treatment of patients with PJI.

Do serologic and synovial tests help diagnose infection in revision hip arthroplasty with metal-on-metal bearings or corrosion?

Background: The diagnosis of periprosthetic joint infection (PJI) in patients with failed metal-on-metal (MoM) bearings and corrosion reactions in hip arthroplasties can be particularly difficult, because the clinical presentation of adverse local tissue reactions may mimic that of PJI, because it can also occur concurrently with PJI, and because common laboratory tests used to diagnose PJI may be elevated in patients with MoM THAs.

Questions/purposes: We sought to determine the test properties of the serum erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), synovial fluid white blood cell (WBC) count, and synovial fluid differential (percent polymorphonuclear cells [PMNs]) in diagnosing PJI in either MoM hips undergoing revision for a variety of indications or in non-MoM hips undergoing revision for either corrosion reaction or full-thickness wear. Additionally, we sought to describe how MoM bearings, metal debris, and corrosion reactions can confound the analysis of the synovial fluid WBC count and affect its diagnostic use for PJI.

Is synovial C-reactive protein a useful marker for periprosthetic joint infection?

Background: Serum C-reactive protein (CRP) is a general marker of inflammation, and recent studies suggest that measurement of CRP in synovial fluid may be a more accurate method for diagnosing periprosthetic joint infection (PJI).

Questions/purposes: We aimed to (1) determine if there is a correlation between serum and synovial CRP values, (2) establish cutoff values for diagnosing infection based on serum and synovial CRP, and (3) compare the utility of measuring CRP in synovial fluid versus serum for the diagnosis of PJI using standard assay equipment available at most hospitals.

Methods: Between February 2011 and March 2012, we invited all 150 patients scheduled for revision TKA (84) or THA (66) to participate in this prospective study, of whom 100% agreed.

Modular tapered implants for severe femoral bone loss in THA: reliable osseointegration but frequent complications.

Background: Modular tapered stems have been suggested as the optimal implants for patients with severe femoral bone loss (Paprosky Type IIIB and IV) undergoing revision total hip arthroplasty (THA); however, there are few data describing survivorship and hip scores associated with this treatment.

Questions/purposes: At minimum 2 years, we sought to determine the (1) survivorship of these implants; (2) radiographic evidence of osseointegration; and (3) the Harris hip scores of patients revised with a modular tapered stem for severe femoral bone loss including the complications associated with their use.

Methods: Between 1999 and 2010, we performed 1124 femoral revisions; of those, 135 (12%) were performed using a modular tapered stem.

Revising an HTO or UKA to TKA: is it more like a primary TKA or a revision TKA?

Forty-nine patients revised from UKA to TKA and 43 from HTO to TKA were matched to 43 aseptic, both component revision TKAs (rTKA) and 97 primary TKAs. At a mean of 4.8 years, the KSS and function scores in the UKA to TKA, HTO to TKA and primary TKA cohorts were similar.

New total knee arthroplasty designs: do young patients notice?

Background: Although the volume of total knee arthroplasties (TKAs) performed in the United States continues to increase, recent reports have shown the percentage of patients who remain "unsatisfied" is as high as 15% to 30%. Recently, several newer implant designs have been developed to potentially improve patient outcomes.

Questions/purposes: The purpose of this study was to determine the impact of high-flex, gender-specific, and rotating-platform TKA designs on patient satisfaction and functional outcomes.

Dislocation of a total hip arthroplasty: acute management in the ED.

Dislocation is one of the most common complications of total hip arthroplasty (THA). Because of the growing number of patients undergoing THA annually and the immense number of patients who have previously undergone the procedure, familiarity with the diagnosis and treatment of this complication is critical. Although the most common direction of dislocation is posterior, anterior dislocations do occur, and correctly identifying the direction of dislocation is important before attempted closed reduction as both the reduction maneuvers used and the postoperative instructions afterward are distinct for an anterior as opposed to a posterior dislocation.

Is potential malnutrition associated with septic failure and acute infection after revision total joint arthroplasty?

Background: Although malnutrition has been hypothesized to increase the risk of periprosthetic joint infection (PJI), strong evidence linking the two is lacking.

Questions/purposes: The purposes of this study were to determine (1) if one or more laboratory values suggestive of malnutrition is independently associated with being revised for an infected joint arthroplasty as opposed to for an aseptic failure; (2) the relationship between laboratory parameters suggestive of malnutrition and obesity; and (3) if one or more laboratory parameters suggestive of malnutrition is independently associated with acute PJI complicating an aseptic revision procedure.

Methods: Between 2002 and 2010, one surgeon performed 600 revision total joint arthroplasties in 547 patients; during that time, nutritional parameters (including serum albumin, total lymphocyte count, and transferrin) were routinely obtained preoperatively; complete data sets were available on 454 patients (501 procedures [84%]).

Let's do a revision total knee arthroplasty.

Numerous steps are required to successfully complete a revision total knee arthroplasty. A review of the technical details of each step will be helpful to arthroplasty surgeons, along with a discussion of reoperative planning, complex surgical exposure techniques, component removal, and the choice of prosthetic components. A review of common difficult issues, including bone loss, ligamentous instability, and management of the extensor mechanism, will also aid in achieving a successful revision total knee arthroplasty.

The inter-observer and intra-observer reliability of the Paprosky femoral bone loss classification system.

The Paprosky classification provides a straightforward algorithm for defining bone loss and directing treatment for femoral revision. The purpose of this study was to test the inter-observer and intra-observer reliability of this system. Four arthroplasty surgeons reviewed radiographs of 205 consecutive femoral revisions.

Evaluation of malnutrition in orthopaedic surgery.

Malnutrition can increase the risk of surgical site infection in both elective spine surgery and total joint arthroplasty. Obesity and diabetes are common comorbid conditions in patients who are malnourished. Despite the relatively high incidence of nutritional disorders among patients undergoing elective orthopaedic surgery, the evaluation and management of malnutrition is not generally well understood by practicing orthopaedic surgeons.

Culture-negative periprosthetic joint infection.

➤ Negative results on culture still pose a real challenge in the diagnosis of periprosthetic joint infection.➤ There are numerous reasons for the inability to isolate the infecting organism from the affected joint, the most important of which is the administration of antibiotics prior to obtaining culture samples.➤ For patients suspected of having a periprosthetic joint infection, antibiotics should not be given until the diagnosis is confirmed or aspiration of the joint should be delayed for at least two weeks after the last dose of antibiotics.

The natural progression of synovial fluid white blood-cell counts and the percentage of polymorphonuclear cells after primary total knee arthroplasty: a multicenter study.

Background: Assessments of the synovial fluid white blood-cell (WBC) count and percentage of polymorphonuclear cells (PMNs) have been reported to be useful in the diagnosis of periprosthetic joint infection. The purpose of this multicenter retrospective study was to evaluate the natural progression of the synovial fluid WBC count, PMN percentage, and total neutrophil count in patients who underwent knee aspiration during the first two years after primary total knee arthroplasty and had no evidence of periprosthetic joint infection.

Methods: From April 1999 to March 2012, 571 patients who presented within the first two years after primary total knee arthroplasty underwent knee aspiration as part of an evaluation for periprosthetic joint infection.

Outcomes and complications of unicondylar arthroplasty.

Unicompartmental knee arthroplasty has experienced resurgence in popularity because of the lower morbidity of the procedure and the proposed benefits over total knee replacement in appropriately selected patients. Improved component designs and advanced surgical techniques have promoted excellent results. Expanded indications to include the very young and the elderly have yielded comparable clinical outcomes.

Dual mobility in total hip arthroplasty.

Dual-mobility articulations have shown promising results. Postoperative instability remains the most common reason for revision of a total hip arthroplasty (THA). Dual-mobility cups have been shown to decrease the rate of dislocation in primary THA and have been used to treat and prevent instability in revision THA.

High level of residual symptoms in young patients after total knee arthroplasty.

Background: TKA is among the fastest growing interventions in medicine, with procedure incidence increasing the most in younger patients. Global knee scores have a ceiling effect and do not capture the presence of difficulty or dissatisfaction with specific activities important to patients.

Questions/purposes: We quantified the degree of residual symptoms and specific functional deficits in young patients who had undergone TKA.

Acute hematogenous infection following total hip and knee arthroplasty.

Forty consecutive patients (42 joints; 22 TKA, 20 THA) treated for acute hematogenous infections were reviewed. All patients underwent irrigation and debridement and exchange of the modular components. At a mean of 56 months (range, 25-124 months) recurrent infection, requiring surgery, developed in 9 of the 42 joints (21%); 8 of the 9 recurrent infections were in patients with a staphylococcal infection (P = 0.

Should draining wounds and sinuses associated with hip and knee arthroplasties be cultured?

We assessed the utility of culturing draining wounds or sinuses in evaluating periprosthetic joint infection (PJI). Fifty-five patients with a draining wound or sinus after total joint arthroplasty (28 knees, 27 hips) who had not received antibiotics for at least two weeks were prospectively studied. Superficial wound cultures were compared to intra-articular cultures to determine accuracy in isolating infecting organism(s).

Increased complication rate following conversion total hip arthroplasty after cephalomedullary fixation for intertrochanteric hip fractures: a multi-center study.

Cephalomedullary devices (CMN) have become an increasingly popular for treatment of intertrochanteric hip fractures compared to sliding hip screw and side plate (SHS) devices. Failed fixation is often treated with conversion total hip arthroplasty (THA). We performed a multi-institutional study in which 60 patients with SHS devices and 31 patients with CMN devices were converted to THA.

Revision of unicompartmental arthroplasty to total knee arthroplasty: not always a slam dunk!

Objective: As the number of UKA performed in the world continues to increase, so will the number of failures. A better understanding of the outcomes after revision UKAto TKA is warranted. The objective of this study is to report the outcomes of modern UKA revised to TKA in three US centers.

The 2013 Frank Stinchfield Award: Diagnosis of infection in the early postoperative period after total hip arthroplasty.

Background: Diagnosis of periprosthetic joint infection (PJI) can be difficult in the early postoperative period after total hip arthroplasty (THA) because normal cues from the physical examination often are unreliable, and serological markers commonly used for diagnosis are elevated from the recent surgery.

Questions/purposes: The purposes of this study were to determine the optimal cutoff values for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), synovial fluid white blood cell (WBC) count, and differential for diagnosing PJI in the early postoperative period after primary THA.

Methods: We reviewed 6033 consecutive primary THAs and identified 73 patients (1.