Todd M. Miner

Risk factors for delayed inpatient functional recovery after total knee arthroplasty

Purpose. To determine the predictive value of surgery-related variables for delayed inpatient functional recovery (i.e., ≥3 days to reach functional independence) after TKA. Method. 193 consecutive people undergoing TKA were included in this prospective cohort study. Inpatient functional recovery was measured daily using the Iowa Level of Assistance scale (ILAS). Two persons reviewed medical records to extract patient characteristics (i.e., age, sex, and BMI) and surgical factors (i.e., blood loss, tourniquet time, postoperative morphine use, and surgical experience). Odds ratios (OR) and area under the curves (AUC) were calculated to determine the predictive value of the putative factors and of the model on delayed functional recovery, respectively. Results. Delayed functional recovery was apparent in 76 (39%) people. Higher age, female sex, and higher BMI were all independent risk factors for delayed functional recovery (AUC (95%-CI); 0.72 (0.65–0.80)), whereas blood loss (OR (95%-CI); 1.00 (0.99–1.01)), tourniquet time (OR = 1.00 (0.98–1.02)), and postoperative morphine use (OR = 0.88 (0.37–2.06)) did not statistically improve the predictive value of the model, while surgical experience did (OR = 0.31 (0.16–0.64); AUC = 0.76 (0.69–83)). Conclusions. Surgery-related factors contribute little to the patient-related characteristics in a predictive model explaining delayed functional recovery after TKA in daily orthopaedic practice.

Early High-Intensity Versus Low-Intensity Rehabilitation After Total Knee Arthroplasty: A Randomized Controlled Trial

To examine the safety and efficacy of a high‐intensity (HI) progressive rehabilitation protocol beginning 4 days after total knee arthroplasty (TKA) compared to a low‐intensity (LI) rehabilitation protocol.

Determining False Positive Rates of Leukocyte Esterase Reagent Strip When Used as a Detection Tool for Joint Infection

BACKGROUND Use of leukocyte esterase (LE) testing of synovial fluid as an adjunct to the infection workup in total joint arthroplasty patients has been advocated. The purpose of this study was to determine the false positive rate of this test. METHODS Two hundred patients with the diagnosis of degenerative osteoarthritis undergoing a total knee arthroplasty were identified for this study. The knee joint was aspirated under sterile conditions before performing the total knee arthroplasty. The fluid was analyzed with an LE reagent strip. RESULTS There were 27 bloody and 17 dry aspirations. One hundred forty-nine patients produced an aspiration that allowed for LE testing. There was 1 positive LE result. The specificity of the LE test was found to be 99.3%. CONCLUSION These data suggest the LE strip as a part of the workup for infection in a native knee should yield few false positive results.

What Preoperative Radiographic Parameters Are Associated With Increased Medial Release in Total Knee Arthroplasty

BACKGROUND Preoperative varus deformity of the knee is a common malalignment in patients undergoing primary total knee arthroplasty (TKA). We are unaware of any studies that have correlated how various preoperative radiographic parameters can predict the amount of medial releases performed to achieve optimal coronal alignment and ligamentous balance. METHODS A retrospective review was performed on 67 patients who required at least a medial tibial reduction osteotomy (MTRO) during primary TKA to achieve coronal balance. This patient population was matched 1:1 to another cohort of TKA patients by age, gender, and body mass index who did not require an MTRO. A radiographic evaluation was used to compare the 2 cohorts. RESULTS Preoperatively, the MTRO cohort was noted to have significantly increased varus tibiofemoral (86.12° vs 93.43°), tibial articular surface (85.79° vs 87.54°), and medial tibial articular surface angles (75.22° vs 85.34°) compared to the control cohort. The MTRO cohort had 3.13 mm of medial tibial offset and 9.06 mm of lateral joint space opening and the control cohort had 0.09 mm and 4.07 mm, respectively. The medial tibial articular surface angle and lateral joint space widening were statistically associated with the MTRO cohort. The final tibiofemoral angle in the MTRO cohort was 92.43° and was 93.40° in the control cohort. CONCLUSION The MTRO cohort was noted to have several preoperative radiographic parameters that were significantly different than the control cohort. However, the medial tibial articular surface angle and lateral joint space widening were the only radiographic parameters that were statistically associated with requiring an MTRO.

False-positive Cultures After Native Knee Aspiration: True or False

BackgroundSynovial fluid aspiration is a routine practice used by most orthopaedic surgeons to aid in the diagnosis of joint infection. In patients for whom there is a low pretest probability of infection, a positive culture—particularly if it is a broth-only culture—may be considered a contaminant, especially if the bacterial species are skin pathogens. To our knowledge no study has evaluated the incidence of contamination of aspirations from the native knee.Questions/purposesWhat is the frequency of false-positive cultures among knee aspirations of the native knee?MethodsTwo hundred patients, with a total of 200 knees, with the diagnosis of degenerative osteoarthritis undergoing a total knee arthroplasty (TKA) were identified for this study. None of these patients had symptoms, signs, or laboratory studies to suggest the presence of joint infection; a positive culture in this population therefore would be considered contaminated. Thirty–two (16%) patients were excluded secondary to a dry aspiration. One patient was enrolled in the study but did not have the knee aspirated and another patient’s specimen was accidentally discarded. Each knee was aspirated under sterile conditions before performing the TKA. The fluid was sent for cell count and culture. If insufficient fluid was obtained for both cell count and culture, culture was performed rather than cell count.ResultsThere were no false-positive cultures (zero of 166 [0%]) in aspirations of native knees.ConclusionsOur study would indicate that when done properly under sterile technique, cultures taken from knee arthrocentesis in patients without prosthetic joints should not be affected by perceived contaminant species. A positive specimen finding on culture should raise a strong suspicion of bacterial septic arthritis. Future studies should include more specimens as well as knees with prior TKA to help further identify the rate of false-positive cultures in knee arthrocentesis in both populations.Level of EvidenceLevel I, diagnostic study.

Metal Artifact Reduction Sequence Mri Abnormalities in Asymptomatic Patients with a Ceramic-on-polyethylene Total Hip Replacement

Background: Magnetic resonance imaging (MRI) is a commonly utilized screening modality in patients with a metal-on-metal (MoM) total hip replacement. The prevalence of clinically important fluid collections may be overestimated since these collections have been reported to occur in asymptomatic patients with MoM and other bearing surfaces. The purpose of this study was to determine the frequency and types of MRI-documented adverse local tissue reactions in asymptomatic patients with a ceramic-on-polyethylene (CoP) total hip replacement. Methods: Forty-four patients (50 hips) with a minimum 2-year follow-up after total hip arthroplasty with CoP implants and a Harris hip score of >90 were enrolled in this study. The inclusion criteria were the absence of hip pain and the availability of appropriate follow-up radiographs. All patients underwent a metal artifact reduction sequence (MARS) MRI scan to determine the presence of fluid collections in asymptomatic patients with a CoP bearing surface. Results: Fluid collections were observed in 9 (18%) of 50 asymptomatic hips in this cohort. There were 5 hips with intracapsular synovitis, and 2 of these hips had a thickened synovium. Extra-articular fluid collections with direct intracapsular communication were identified in 4 additional hips. Two of these hips had a thickened synovium. No signs of osteolysis or evidence of adverse local tissue reactions were noted on radiographs at the most recent follow-up. Conclusions: This study revealed that fluid collections are not uncommon after total hip arthroplasty with CoP implants. Synovial thickening may be present and is more prevalent than has been reported in previous studies involving metal-on-polyethylene (MoP) bearing surfaces. The clinical importance and natural history of these findings remain unknown. Level of Evidence: Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Use of a computerized arthroplasty registry to generate operative reports decreases transcription errors

OBJECTIVES Despite the clear importance of the operative report in the electronic medical record, few studies have addressed the quality. METHODS We prospectively evaluated 300 consecutive patients undergoing primary total joint arthroplasties for operative report errors utilizing three different forms of documentation (standard dictation vs. templated dictation vs. a computer registry database generated operative report). The three types of reports were evaluated for errors which were classified as either major or minor. RESULTS There were significantly more total errors in the standard dictation group compared to both the computer registry database generated (p<0.001) and the templated operative reports (p<0.001). Major errors were significantly reduced in the database generated reports compared to the templated (p<0.001) and standard dictation groups (p<0.001). There were significantly more minor errors in the standard dictation group (p<0.001) compared to the other two groups. No statistically significant differences in major errors were noted when comparing standard vs. templated operative reports. There was no difference in minor or total errors between the database generated and templated operative reports. CONCLUSIONS The use of a computer registry database generated operative report resulted in fewer major errors versus a templated or standard dictated operative report. Further research is warranted in this area to validate these findings across subspecialties and institutions.

Reply to the Letter to the Editor: False-positive Cultures After Native Knee Aspiration: True or False

W e agree that a culturepositive specimen suggests that bacteria are present, and we agree that the term ‘‘false-positive’’ needs to be revisited. Clinicians cannot cavalierly dismiss any culture result that was properly obtained. This highlights the importance of meticulous harvesting and laboratory technique when handling specimens. The anaerobic conditions of an agar with kanamycin and vancomycin may affect the detection of Propionibacterium. Although not included in the manuscript, our laboratory used a blood agar without kanamycin and vancomycin, which would not interfere with the ability of these cultures to detect Propionibacterium.

Primary total knee arthroplasty in a patient with a chronic extensor mechanism deficiency

A 44-year-old female presented with a chief complaint of left knee pain and dysfunction. The patient had a complex surgical history including patellar fracture repair, subsequent patellar ligament repair, and ultimately allograft reconstruction which was complicated by septic arthritis requiring graft resection. On presentation to our clinic, she was noted to have significant degenerative disease in addition to chronic extensor mechanism deficiency. She underwent primary total knee arthroplasty with concomitant tibial tubercle osteotomy and advancement. The patient has had an excellent result postoperatively including return of full range of motion without residual extensor lag.