Atraumatic Fracture of Cemented Vanguard Total Knee Arthroplasty Femoral Component.

The authors report the case of an atraumatic femoral component fracture 10 years after primary total knee arthroplasty (TKA) with a modern cemented fixed bearing system. The patient, a 70-year-old man, had the complication without inciting trauma, and he subsequently had severe pain and disability. This rare mode of TKA failure occurred at the superolateral aspect of the femoral component's anterior flange. At the time of revision, no femoral osteolysis was seen and the backside of the prosthesis fracture fragment was found to be free of cement. To the authors' knowledge, this is the first case of femoral component fracture in a Vanguard TKA (Biomet, Warsaw, Indiana), and the first case of fracture in a modern cobalt-chrome alloy femoral component associated with aseptic cement debonding. Femoral component stress fracture is a rare but serious complication of TKA. Reports of femoral component fracture in early designs were attributed to geometric design flaws, whereas modern TKA designs appear to fail when ingrowth failure, aseptic debonding, or osteolysis result in inadequate bony support of the prosthesis. Careful attention to bone cuts in porous-coated uncemented TKA systems and proper cementing technique in cemented TKA systems may preclude this rare complication. In the case of severe osteolysis, early revision may prevent catastrophic implant failure. [Orthopedics. 2020;43(5):e476-e479.].

Acetabular Reconstruction With the Medial Protrusio Technique for Complex Primary and Revision Total Hip Arthroplasties.

BACKGROUND: In the setting of acetabular deficiency during total hip arthroplasty (THA), the medial protrusio technique (MPT) allows for increased component coverage while avoiding excessive component abduction or elevation of the hip center. The technique involves controlled reaming through the medial acetabular wall while maintaining the continuity of the anterior and posterior columns. The purpose of this study is to analyze the results of the largest reported series to date of primary and revision THAs using the MPT. METHODS: A retrospective review of THAs performed by a single surgeon from July 2004 to July 2010 identified 102 patients who underwent THA necessitating the use of the MPT (primary 86 and revision 16), with at least 2 years follow-up. RESULTS: This study reports the largest series to date of primary and revision THAs using the MPT for acetabular deficiency. Postoperatively, mean Harris hip score was 86 (range 31-96). There was no correlation with degree of medialization and change in Harris hip score (P = .12). At mean follow-up of 41.1 months (range 24-92 months), there were no intrapelvic structure injuries and no acetabular components required revision. The MPT provided a safe and effective method for addressing acetabular deficiency and avoiding component malposition. CONCLUSION: The MPT provided a safe and effective method for addressing acetabular deficiency in this large series of patients. The technique was successful at improving component coverage while maintaining an anatomic hip center and avoiding excessive component abduction. Fixation remained durable with no cases of loosening at final follow-up.

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.

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

BACKGROUND: Synovial 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/PURPOSES: What is the frequency of false-positive cultures among knee aspirations of the native knee? METHODS: Two 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. RESULTS: There were no false-positive cultures (zero of 166 [0%]) in aspirations of native knees. CONCLUSIONS: Our 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 EVIDENCE: Level I, diagnostic study.