Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence Patients.

ABSTRACT: There has yet to be a consensus on the appropriate technique for mandibular distraction in the infant Pierre Robin population nor is their sufficient data on sensory nerve outcomes. The purpose of this study is to validate the safety of the horizontal osteotomy by: (1) determining mandibular foramen location in infant Pierre Robin patients relative to the dentoalveolar plane and (2) evaluate long-term function of the inferior alveolar nerve in previously distracted Pierre Robin patients. Preoperative 3D Computed tomography (CT) scans of Pierre Robin patients < 1 year old were reviewed. A line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen was then measured. Semmes-Weinstein monofilaments of the lower lip and chin bilaterally was performed on mandibular distraction patients in clinic. Inclusion criteria was patients >6 years of age having undergone bilateral mandibular distraction at <1 year of age. Fifteen patients' CT studies were examined. The mandibular foramen was consistently below the level of the dentoalveolar plane at an average distance of 4.7 mm. Eight patients were included in the prospective arm. Average age was 12.2. All patients had normal sensation at 2.83 through all areas. The mandibular foramen reliably exists below the dentoalveolar plane. In addition, all patients reviewed postoperatively with >10 years of follow up demonstrated normative sensation. The horizontal corticotomy performed just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in young Pierre Robin patients undergoing distraction.

Total Femur Antibiotic Spacers: Effective Salvage for Complex Periprosthetic Joint Infections.

BACKGROUND: A simultaneous periprosthetic joint infection (PJI) of an ipsilateral hip and knee arthroplasty is a challenging complication of lower extremity reconstructive surgery. We evaluated the use of total femur antibiotic-impregnated polymethylmethacrylate (PMMA) bone cement spacers in the staged treatment of such limb-threatening PJIs. METHODS: Thirteen patients were treated with a total femur antibiotic spacer. The mean age at the time of spacer placement was 65 years. Nine patients had polymicrobial PJIs. All spacers incorporated vancomycin (3.0 g/40 g PMMA) and gentamicin (3.6 g/40 g PMMA), while 8 also included amphotericin (150 mg/40 g PMMA). Eleven spacers were biarticular. Twelve spacers were implanted through one longitudinal incision, while 8 of 12 reimplantations occurred through 2 smaller, separate hip and knee incisions. Mean follow-up after reimplantation was 3 years. RESULTS: Twelve (92%) patients underwent reimplantation of a total femur prosthesis at a mean of 26 weeks. One patient died of medical complications 41 days after spacer placement. At latest follow-up, 3 patients had experienced PJI recurrence managed with irrigation and debridement. One required acetabular component revision for instability. All 12 reimplanted patients retained the total femur prosthesis with no amputations. Eleven (91%) were ambulatory, and 7 (58%) remained on suppressive antibiotics. CONCLUSION: Total femur antibiotic spacers are a viable, but technically demanding, limb-salvage option for complex PJIs involving the ipsilateral hip and knee. In the largest series to date, there were no amputations and 75% of reimplanted patients remained infection-free. Radical debridement, antimicrobial diversity, prolonged spacer retention, and limiting recurrent soft tissue violation are potential tenets of success. LEVEL OF EVIDENCE: IV.

Comparison of Three Commercial Tools for Metagenomic Shotgun Sequencing Analysis.

Metagenomic shotgun sequencing for the identification of pathogens is being increasingly utilized as a diagnostic method. Interpretation of large and complicated data sets is a significant challenge, for which multiple commercial tools have been developed. Three commercial metagenomic shotgun sequencing tools, CosmosID, One Codex, and IDbyDNA, were compared to determine whether they result in similar interpretations of the same sequencing data. We selected 24 diverse samples from a previously characterized data set derived from DNA extracted from biofilms dislodged from the surfaces of resected arthroplasties (sonicate fluid). Sequencing data sets were analyzed using the three commercial tools and compared to culture results and prior metagenomic analysis interpretation. Identical interpretations from all three tools occurred for 6 samples. The total number of species identified included 28 by CosmosID, 59 by One Codex, and 41 by IDbyDNA. All of the tools performed similarly in detecting those microorganisms identified by culture, including polymicrobial mixes. These data show that while all of the tools performed well overall, there were some differences, particularly in their predilection for identifying low-abundance or contaminant organisms as present.

Aseptic Reoperations Within 1 Year of Primary Total Knee Arthroplasty Markedly Increase the Risk of Later Periprosthetic Joint Infection.

BACKGROUND: Despite the high rate of success of primary total knee arthroplasty (TKA), some patients are candidates for early aseptic reoperation. The goal of this study is to evaluate the risk of subsequent periprosthetic joint infection (PJI) in patients treated with an aseptic reoperation within 1 year of primary TKA. METHODS: A retrospective review of our total joint registry compared 249 primary TKAs requiring an aseptic reoperation within 1 year following index arthroplasty to a control group of 17,867 TKAs not requiring reoperation within 1 year. Patients were divided into groups based on time from index TKA: (1) 90 days or less (114 TKAs) and (2) 91 to 365 days (135 TKAs). Mean age was 68 years with 57% female. Mean follow-up was 7 years. RESULTS: At 2 years postoperatively, patients undergoing an aseptic reoperation within 90 days subsequently had a 9% PJI rate, while patients undergoing an aseptic reoperation between 91 and 365 days subsequently had a 3% PJI rate. The control group had a 0.4% PJI rate. Compared to the control group, patients undergoing an aseptic reoperation within 90 days had an elevated risk of PJI (hazard ratio, 9; P < .0001), as did patients who had a reoperation between 91 and 365 days (hazard ratio, 4; P < .0001). CONCLUSION: Aseptic reoperation within 1 year of primary TKA was associated with a notably increased risk of subsequent PJI.

The Lawrence D. Dorr Surgical Techniques & Technologies Award: Aseptic Reoperations Within One Year of Primary Total Hip Arthroplasty Markedly Increase the Risk of Later Periprosthetic Joint Infection.

BACKGROUND: Despite the success of primary total hip arthroplasties (THAs), some patients will require an aseptic reoperation within 1 year of the index THA. The goal of this study is to evaluate the risk of subsequent periprosthetic joint infection (PJI) in patients undergoing an aseptic reoperation within 1 year of a primary THA. METHODS: A retrospective review utilizing our institutional joint registry identified 211 primary THAs requiring aseptic reoperation within 1 year following index arthroplasty. A control group of 15,357 primary THAs not requiring reoperation within 1 year was identified. Patients were divided into groups based on time from primary THA to reoperation: (1) within 90 days (n = 112 THAs; 40% for dislocation, 34% for periprosthetic fracture) or (2) 91-365 days (n = 99 THAs; 37% for dislocation, 29% for periprosthetic fracture). Mean follow-up was 7 years. RESULTS: Patients undergoing an aseptic reoperation within 90 days had a PJI rate of 4.8% at 2 years, while the 91-365 day group had a PJI rate of 3.2% at 2 years. The control group had a PJI rate of 0.2% at 2 years. Employing a multivariate analysis, reoperation within 90 days of index arthroplasty had an elevated risk of PJI (hazard ratio 8, P < .001) as did a reoperation between 91 and 365 days (hazard ratio 13, P < .001). CONCLUSION: Aseptic reoperations within 1 year following primary THA resulted in an 8- to 13-fold increased risk of subsequent PJI. The risk was similar whether the aseptic reoperation was early (within 90 days) or later (91-365 days). LEVEL OF EVIDENCE: Level III (Prognostic).

Elevated Infection and Complication Rates in Patients Undergoing a Primary THA With a History of a PJI in a Prior Hip or Knee Arthroplasty: A Matched Cohort Study.

BACKGROUND: There are little data on the outcomes of primary total hip arthroplasties (THAs) in patients with a prior surgically treated hip or knee periprosthetic joint injection (PJI). The goal of this study was to compare the risk of infection in this population with matched controls. METHODS: We retrospectively reviewed 48 patients whom underwent 50 primary THAs from 2000 to 2014 with a history of a PJI in a total knee arthroplasty or contralateral THA. Thirteen patients (27%) were on chronic antibiotic suppression at the time of primary THA. Mean age was 67 years, and mean body mass index was 35 kg/m2. Mean follow-up was 6 years. We 1:3 matched (age, sex, body mass index, cemented vs cementless femoral fixation, and surgical year) these cases to 150 primary THAs. Competing risk analysis, with death as the competing risk, was performed. RESULTS: The cumulative incidence of PJI with death as a competing risk was 1.5-fold higher in the study cohort (2.0%) compared with matched controls (1.4%) (hazards ratio, 1.5; P = .75). The cumulative incidence of any infection with death as a competing risk was 2-fold higher in the study cohort (4.0%) compared with matched controls (2.1%) (hazards ratio, 2.0; P = .45). However, these were both statistically similar given the relatively small cohort. The overall complication rate, including infections and reoperations, was 17% in the study cohort. CONCLUSION: Patients undergoing a clean primary THA with a history of a total knee arthroplasty or contralateral THA PJI in another joint have a 2% and 4% risk of PJI and any infection, respectively. Moreover, nearly 1 in 5 patients experience at least 1 complication.

Measuring the Position of the Mandibular Foramen in Relation to the Dentoalveolar Plane in Pierre Robin Patients: Establishing Safety of the Horizontal Osteotomy.

BACKGROUND: Mandibular distraction with horizontal osteotomy of the ramus and vertical distraction vector has successfully treated airway obstruction in young Pierre Robin patients. Placing the osteotomy just above the dentoalveolar plane can minimize damage to the inferior alveolar nerve. This study maps the position of the mandibular foramen relative to the height of the dentoalveolar plane to demonstrate the safety of this technique in Pierre Robin neonates. METHODS: Retrospective review of 3D CT scans of Pierre Robin patients was performed with inclusion criteria: ≤1 year of age, bilateral micrognathia requiring surgical intervention for airway (ie, tracheostomy versus mandibular distraction), no prior mandible surgery, and pre-operative 3D CT study. Demographic information collected included: age at CT scan, age at surgery, and genetic diagnosis. Using the 3D study of each patient's right mandible, a line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen at a length perpendicular to the dentoalveolar plane line was then measured. RESULTS: Fifteen patients were included in the study (at least 9 Pierre Robin). Average age at time of CT scan was 71.4 days old. The mandibular foramen was below the level of the dentoalveolar plane in all cases at an average distance of 4.7 mm. Average ramus height 46.2±13.4 CONCLUSIONS:: The dentoalveolar plane was consistently above the mandibular foramen in all patients. Thus, the horizontal corticotomy at a level just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in neonatal Pierre Robin patients undergoing vertical vector mandibular distraction.

Infection After Unicompartmental Knee Arthroplasty: A High Risk of Subsequent Complications.

BACKGROUND: Unicompartmental knee arthroplasty restores function and improves pain in appropriately selected patients. Scant evidence exists regarding the treatment of periprosthetic joint infection (PJI) after unicompartmental knee arthroplasty (UKA). QUESTIONS/PURPOSES: (1) What was the overall survivorship free from reinfection? (2) What is the survivorship free of all-cause revision? (3) What are the Knee Society scores (KSS) and complications after surgical treatment of UKA PJI? METHODS: This retrospective study with data drawn from a longitudinally maintained institutional registry identified 15 UKA PJIs between 1992 and 2014. The median age at PJI diagnosis was 58 years (range, 41-82 years), nine of 15 were men, and the median body mass index was 29 kg/m (range, 23-36 kg/m). Ten patients (10 of 15) satisfied major Musculoskeletal Infection Society diagnostic criteria. There were five patients (five of 15) with early postoperative infections, five (five of 15) with acute hematogenous infections, and five (five of 15) with chronic PJIs. Two-stage exchange was performed in four patients with PJIs (four of 15), and débridement, antibiotics, and implant retention (DAIR) was performed in 11 patients (11 of 15) with PJIs. We performed Kaplan-Meier survivorship analysis for reinfection and revision procedures. Thirteen patients had a minimum of 2 years' followup and were included in the clinical analysis. Median followup was 4 years (range, 2-6 years). We calculated KSS. RESULTS: Infection-free survivorship was 71% at 5 years (95% confidence interval [CI], 46%-96%). Treatment success was higher for patients undergoing two-stage exchange (100% at 5 years; 95% CI, 100%-100%) versus DAIR (61% at 5 years; 95% CI, 31%-92%). Four of 11 patients undergoing DAIR had developed a reinfection at final followup. Survivorship free of any revision was 49% at 5 years (95% CI, 19%-79%). One patient from the two-stage exchange cohort underwent femoral component revision for aseptic loosening 5 years after PJI treatment, and two patients from the DAIR group were converted to TKA for disease progression at a mean of 4 years. In patients with a minimum of 2 years' followup, median KSS improved from 73 (range, 50-93) before index UKA to 94 (range, 55-100; p = 0.016). CONCLUSIONS: Treatment of UKA PJI with DAIR was associated with a lower infection-free survivorship at 5 years compared with two-stage exchange with conversion to TKA. Among those patients who were infection-free, a number needed reoperations for disease progression (in the DAIR group) or component loosening (in both groups). UKA PJI results in substantial morbidity, and patients with these infections should be followed closely for aseptic causes of failure in addition to infection recurrence. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Molecular pathology of total knee arthroplasty instability defined by RNA-seq.

Total knee arthroplasty (TKA) is a durable and reliable procedure to alleviate pain and improve joint function. However, failures related to flexion instability sometimes occur. The goal of this study was to define biological differences between tissues from patients with and without flexion instability of the knee after TKA. Human knee joint capsule tissues were collected at the time of primary or revision TKAs and analyzed by RT-qPCR and RNA-seq, revealing novel patterns of differential gene expression between the two groups. Interestingly, genes related to collagen production and extracellular matrix (ECM) degradation were higher in samples from patients with flexion instability. Partitioned clustering analyses further emphasized differential gene expression patterns between sample types that may help guide clinical interpretations of this complication. Future efforts to disentangle the effects of physical and biological (e.g., transcriptomic modifications) risk factors will aid in further characterizing and avoiding flexion instability after TKA.

Cost Analysis of Dual-Mobility Versus Large Femoral Head Constructs in Revision Total Hip Arthroplasty.

BACKGROUND: The purpose of this study is to report healthcare payer costs of dual-mobility (DM) and large femoral head (LFH) constructs in revision total hip arthroplasties (THAs). METHODS: A Markov model was constructed to analyze costs of re-interventions incurred by Medicare and private payers over a 3-year time horizon in patients who underwent unilateral revision THA with DM (n = 126) or LFH (n = 176) implants. Model states and probabilities were derived from prospectively collected registry data. Medicare costs were estimated as the weighted-average national Medicare payment for revision THA. Private payer costs were estimated by using a multiplier of Medicare costs. RESULTS: Over a 3-year period following revision THA, re-interventions were performed in 11 (9%) DM patients and 34 (19%) LFH patients, costing $263-$1898 in DM THAs and $1285-$3946 in LFH THAs for Medicare. When compared to LFH implants, DM constructs were less costly to Medicare and private payers, resulting in cost differentials of $1536 and $2611, respectively. CONCLUSIONS: At mid-term follow-up, DM constructs utilized in revision THAs were associated with 11% lower absolute risk of re-intervention and payer savings of $1500-$2500 per case when compared to LFH constructs. LEVEL OF EVIDENCE: Economic and decision analysis, Level III.

Mild Coronal Stem Malalignment Does Not Negatively Impact Survivorship or Clinical Results in Uncemented Primary Total Hip Arthroplasties With Dual-Tapered Implants.

BACKGROUND: Proper component positioning in total hip arthroplasty (THA) is crucial for implant fixation and hip stability. The purpose of this study is to assess if neutral coronal stem alignment (0° ± 3°) improved long-term survivorship in uncemented femoral components. METHODS: Between 2005 and 2010, 1028 primary THAs were performed with 2 contemporary dual-tapered, proximally coated uncemented stem types. Alignment was measured immediately postoperatively and at most recent follow-up. In total, 978 femoral stems (95%) were within 0° ± 3° of the neutral anatomic coronal axis, and the 50 stems (5%) outside that range were considered outliers (3.1° of valgus to 4.8° of varus). Outcomes analyzed included implant survivorship, Harris Hip Scores, and incidence of dislocation. Mean follow-up was 5 years. RESULTS: Survivorship free of aseptic femoral component loosening was 99.3% and 98.2% at 5 and 8 years in the neutral group vs 100% at 5 and 8 years in the outlier group (P = .98). Survivorship free of femoral component revision for any reason was 99.1% and 97.3% at 5 and 8 years vs 100% at 5 and 8 years, respectively (P = .80). Harris Hip Scores were similar (89 in both groups; P = .84) at most recent follow-up. The incidence of mild to moderate thigh pain was also similar in both groups (6.1% vs 6%, P = .85). The incidence of dislocation was 1.5% at 8 years, and similar between both groups (P = .77). CONCLUSION: Slight malalignment of contemporary dual-tapered uncemented THA femoral components does not appear to negatively impact survivorship or clinical outcomes, which is in contrast to cemented femoral components. LEVEL OF EVIDENCE III: Case-control study.

Identification of Prosthetic Joint Infection Pathogens Using a Shotgun Metagenomics Approach.

Background: Metagenomic shotgun sequencing has the potential to change how many infections, particularly those caused by difficult-to-culture organisms, are diagnosed. Metagenomics was used to investigate prosthetic joint infections (PJIs), where pathogen detection can be challenging. Methods: Four hundred eight sonicate fluid samples generated from resected hip and knee arthroplasties were tested, including 213 from subjects with infections and 195 from subjects without infection. Samples were enriched for microbial DNA using the MolYsis basic kit, whole-genome amplified, and sequenced using Illumina HiSeq 2500 instruments. A pipeline was designed to screen out human reads and analyze remaining sequences for microbial content using the Livermore Metagenomics Analysis Toolkit and MetaPhlAn2 tools. Results: When compared to sonicate fluid culture, metagenomics was able to identify known pathogens in 94.8% (109/115) of culture-positive PJIs, with additional potential pathogens detected in 9.6% (11/115). New potential pathogens were detected in 43.9% (43/98) of culture-negative PJIs, 21 of which had no other positive culture sources from which these microorganisms had been detected. Detection of microorganisms in samples from uninfected aseptic failure cases was conversely rare (7/195 [3.6%] cases). The presence of human and contaminant microbial DNA from reagents was a challenge, as previously reported. Conclusions: Metagenomic shotgun sequencing is a powerful tool to identify a wide range of PJI pathogens, including difficult-to-detect pathogens in culture-negative infections.

Direct Detection and Identification of Prosthetic Joint Infection Pathogens in Synovial Fluid by Metagenomic Shotgun Sequencing.

Metagenomic shotgun sequencing has the potential to transform how serious infections are diagnosed by offering universal, culture-free pathogen detection. This may be especially advantageous for microbial diagnosis of prosthetic joint infection (PJI) by synovial fluid analysis since synovial fluid cultures are not universally positive and since synovial fluid is easily obtained preoperatively. We applied a metagenomics-based approach to synovial fluid in an attempt to detect microorganisms in 168 failed total knee arthroplasties. Genus- and species-level analyses of metagenomic sequencing yielded the known pathogen in 74 (90%) and 68 (83%) of the 82 culture-positive PJIs analyzed, respectively, with testing of two (2%) and three (4%) samples, respectively, yielding additional pathogens not detected by culture. For the 25 culture-negative PJIs tested, genus- and species-level analyses yielded 19 (76%) and 21 (84%) samples with insignificant findings, respectively, and 6 (24%) and 4 (16%) with potential pathogens detected, respectively. Genus- and species-level analyses of the 60 culture-negative aseptic failure cases yielded 53 (88%) and 56 (93%) cases with insignificant findings and 7 (12%) and 4 (7%) with potential clinically significant organisms detected, respectively. There was one case of aseptic failure with synovial fluid culture growth; metagenomic analysis showed insignificant findings, suggesting possible synovial fluid culture contamination. Metagenomic shotgun sequencing can detect pathogens involved in PJI when applied to synovial fluid and may be particularly useful for culture-negative cases.

Otto Aufranc Award: Dual-mobility Constructs in Revision THA Reduced Dislocation, Rerevision, and Reoperation Compared With Large Femoral Heads.

BACKGROUND: Dislocation is one of the most common complications after revision THA. Dual-mobility constructs and large femoral heads (ie, 40 mm) are two contemporary, nonconstrained bearing options used in revision THA to minimize the risk of dislocation; however, it is not currently established if there is a clear benefit to using dual-mobility constructs over large femoral heads in the revision setting. QUESTIONS/PURPOSES: We sought to determine if dual-mobility constructs would provide a reduction in dislocation, rerevision for dislocation, and reoperation or other complications as compared with large femoral heads in revision THA. METHODS: From 2011 to 2014, a series of 355 THAs underwent revision for any reason and received either a dual-mobility construct (146 THAs) or a 40-mm large femoral head (209 THAs). Indications for either construct were based on surgeon judgment; however, there is a preference to use dual-mobility constructs in patients believed to be at higher risk of dislocation. In the dual-mobility group, 20 of 146 (14%) were excluded because of loss of followup before 2 years or because they had a dual-mobility shell cemented into a preexisting acetabular component. In the large head group, 33 of 209 (16%) were lost to followup before 2 years. Followup in the dual-mobility group was 3.3 ± 0.8 years and followup in the large head group was 3.9 ± 0.9 years. Primary endpoints included dislocation, rerevisions for dislocation, and reoperations, which were determined through our institution's total joint registry and verified by individual patient chart review. Age and body mass index were not different with the numbers available between the groups, but there was a slight predominance of females in the dual-mobility group (52% [66 of 126] female) versus the 40-mm large head group (41% [72 of 176] female) (p = 0.05). Notably, 33% (41 of 126) of patients receiving the dual-mobility constructs had the index revision THA done for a diagnosis of recurrent dislocation versus 9% (17 of 176) in the 40-mm large head group. Mean effective head size in the dual-mobility group was 47 mm (range, 38-58 mm). RESULTS: The subsequent frequency of dislocation in the dual-mobility construct group was less (3% [four of 126] dual-mobility versus 10% [17 of 176] in the 40-mm large head group; hazard ratio, 3.2 [1.1-9.4]; p = 0.03). Rerevision for dislocation in the dual-mobility construct group was less frequent (1% [one of 126] dual-mobility versus 6% [10 of 176] in the 40-mm large head group; hazard ratio, 7.1 [0.9-55.6]; p = 0.03). Reoperation for any cause in the dual-mobility construct group was less frequent (6% [eight of 126] dual-mobility versus 15% [27 of 176] in the 40-mm large head group; hazard ratio, 2.5 [1.1-5.5]; p = 0.02); there were no differences between the groups in terms of the overall percentage of complications in each group. CONCLUSIONS: When compared with patients treated with a 40-mm large femoral head, patients undergoing revision THA who received a dual-mobility construct had a lower risk of subsequent dislocation, rerevision for dislocation, and reoperation for any reason in the first several years postoperatively. Those findings were present despite selection bias in this study to use the dual-mobility construct in patients at the highest risk for subsequent dislocation. Given the lower risk of subsequent dislocation, rerevision, and reoperation with the dual-mobility construct, some surgeons may wish to consider whether the role of dual-mobility should be judiciously expanded in contemporary revision THA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Two-Stage Revision Total Hip Arthroplasty With a Specific Articulating Antibiotic Spacer Design: Reliable Periprosthetic Joint Infection Eradication and Functional Improvement.

BACKGROUND: Two-stage revision utilizing spacers loaded with high-dose antibiotic cement prior to reimplantation remains the gold standard for treatment of periprosthetic joint infections (PJI) in total hip arthroplasty (THA) in North America, but there is a paucity of data on mid-term outcomes. We sought to analyze the survivorship free of infection, clinical outcomes, and complications of a specific articulating spacer utilized during 2-stage revision. METHODS: One hundred thirty-five hips (131 patients) undergoing a 2-stage revision THA for PJI with a specific articulating antibiotic spacer design from 2005 to 2013 were retrospectively reviewed. Infections were classified according to the Musculoskeletal Infection Society criteria. Mean age at resection was 65 years and mean follow-up was 5 years (rang, 2-10). RESULTS: Survivorship free of any infection after reimplantation was 92% and 88% at 2 and 5 years, respectively. Patients with a host-extremity grade of C3 compared to all patients with a host grade of A [hazard ratio (HR) 4.1, P = .05] were significant risk factors for poorer infection-free survivorship after reimplantation. Harris hip scores improved from a mean of 58 to a mean of 71 in the spacer phase (P = .002) and a mean of 81 post-reimplantation (P = .001). Fourteen (10%) patients dislocated after reimplantation, 9 (7%) of which required re-revision. Trochanteric deficiency (HR 19, P < .0001), dislocation of the articulating spacer prior to reimplantation [which occurred in 7 (5%) patients, 5 of whom subsequently dislocated the definitive implant] (HR 16, P < .0001), and female gender (HR 5, P = .002) were significant risk factors for post-reimplantation dislocation. CONCLUSION: Insertion of an articulating antibiotic spacer during a 2-stage revision THA for PJI demonstrates reliable infection eradication and improvement in clinical function, including the spacer phase. Patients with trochanteric deficiency and an articulating spacer dislocation are at high risk of post-reimplantation dislocation; judicial use of a dual-mobility or constrained device should be considered in these patients.

High Rate of Positive Cultures in Patients Referred With Antibiotic Spacers as Part of 2-Stage Exchange.

BACKGROUND: Two-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains the gold standard treatment in North America. Occasionally, patients with knee PJI are referred for definitive management after resection and antibiotic spacer placement. Currently, little literature exists to suggest how these patients should be managed. The purpose of this study is to report the clinical outcomes of these patients. METHODS: We retrospectively identified 54 patients (54 knees) from 2000 to 2012 treated for PJI with initial TKA resection and spacer placement performed somewhere other than the definitive treatment center. The mean age at reimplantation was 64 years, with 59% being male. Redebridement and antibiotic spacer exchange was performed for all patients. Mean follow-up was 6.5 years. RESULTS: Of the 54 knees, 22 (41%) grew an organism from a culture taken at the time of redebridement and spacer exchange. The most common organism identified at redebridement was Staphylococcus aureus (41%). Obtaining positive cultures at redebridement was not associated with presenting erythrocyte sedimentation rate (P = .46), C-reactive protein (P = .57), or the presence of retained cement (P = .13). Forty-nine of 54 (91%) knees were ultimately reimplanted. Two-year survivorship free of infection in reimplanted knees was 98%. CONCLUSION: Patients referred with an antibiotic knee spacer for PJI have a high rate of positive cultures at the time of redebridement. Neither the presenting serology nor the identification of retained cement was associated with obtaining positive cultures at the time of redebridement. Nevertheless, this unique cohort of patients has favorable outcomes when redebrided with spacer exchange prior to reimplantation.

Periprosthetic Joint Infection With Fungal Pathogens.

BACKGROUND: Although there is abundant information about bacterial periprosthetic joint infections (PJIs), there is a notable paucity of information about fungal PJIs. The goals of this study are to describe the patient demographics, diagnostic findings, and treatment results of fungal PJIs after total joint arthroplasty. METHODS: We identified 31 fungal PJIs (13 total hip arthroplasties and 18 total knee arthroplasties) in 31 patients treated between 1996 and 2014. This represented 0.9% of the 3525 PJIs treated at our institution during this time period. Candida species accounted for 81% of infections. The mean patient age at diagnosis of fungal PJI was 68 years. Mean follow-up after initiation of treatment was 4 years. RESULTS: In the total hip arthroplasty cohort, survivorship free from all-cause revision or implant removal was 44% at 2 years. Survivorship free from reinfection was 38% at 2 years. Mean Harris hip score was 27 at final follow-up.In the total knee arthroplasty cohort, survivorship free from all-cause revision was 70% at 2 years. Survivorship free from reinfection was 76% at 2 years. Mean Knee Society scores were 36 at final follow-up. CONCLUSION: Fungal PJIs are rare (0.9% of diagnosed PJIs). Survivorship free of all-cause revision or implant removal was very low in the hip group (44% at 2 years), but slightly better in the knee group (70% at 2 years). Moreover, clinical outcomes were poor with high perioperative complication rates. Improved treatment regimens are needed for this unsolved clinical problem.

Improvement of Color Vision Following Posterior Cranial Vault Distraction for Crouzon Syndrome.

Crouzon syndrome (CS) is one of the craniosynostosis syndromes that leads to early fusion of cranial sutures and increased intracranial pressure. Intracranial hypertension is a serious complication that may lead to vision loss and cognitive impairment. Early detection and management are necessary to prevent complications. The authors present a patient with CS who underwent posterior cranial vault reconstruction with internal distraction after multiple episodes of headache and papilledema. The patient was unaware of any loss of color vision before the surgery; however, he noted an improvement in his color vision after the surgery. Color vision deficits may be an early sign of intracranial hypertension and finding these deficits using noninvasive testing methods may be an indication for early intervention.

Unilateral Orticochea Pharyngoplasty for Unilateral Velopharyngeal Dysfunction: Long-Term Outcomes Data.

A unilateral deficit in velopharyngeal closure during speech production is an unusual presentation of velopharyngeal dysfunction (VPD) and few solutions have been described for this problem. This report details the long-term outcomes using this technique. We performed a retrospective chart review of all the patients who underwent a unilateral Orticochea pharyngoplasty for VPD. The authors identified 10 patients treated with 11 unilateral pharyngoplasty at a single tertiary care institutional setting. The mean age at repair was 8.6 years. The mean length of follow-up was 7.6 years. All the patients demonstrated improvement in velopharyngeal closure and speech resonance with 4 showing complete resolution of VPD. There were no revisions required or complications. One patient, after 10.7 years, required a unilateral procedure on the contralateral side which resulted in complete resolution of VPD postoperatively.

Computer Simulation and Optimization of Cranial Vault Distraction.

OBJECTIVE: The objective of this study was to validate the proof of concept of a computer-simulated cranial distraction, demonstrating accurate shape and end volume. DESIGN: Detailed modeling was performed on pre- and postoperative computed tomographic (CT) scans to generate accurate measurements of intracranial volume. Additionally, digital distraction simulations were performed on the preoperative scan and the resultant intracranial volume and shape were evaluated. SETTING: Tertiary Children's Hospital. PATIENTS, PARTICIPANTS: Preoperative and postoperative CT images were used from 10 patients having undergone cranial distraction for cephalocranial disproportion. INTERVENTIONS: None; computer simulation. MAIN OUTCOME MEASURE: Computer simulation feasibility of cranial vault distraction was demonstrated through creation of digital osteotomies, simulating distraction through translating skull segments, followed by simulated consolidation. Accuracy of the model was evaluated through comparing the intracranial volumes of actual and simulated distracted skulls. RESULTS: The developed digital distraction simulation was performed on the CT images of 10 patients. Plotting the relationship between the actual and simulated postdistraction volumes for the 10 patients yielded a slope of 1.0 and a correlation coefficient of 0.99. The average actual resultant volume change from distraction was 77.0 mL, compared to a simulated volume change of 76.9 mL. CONCLUSIONS: Digital simulation of cranial distraction was demonstrated through manipulation of the CT images and confirmed by comparing the actual to simulated volume change. This process may provide objective data in designing an individual distraction plan to optimize volume expansion and resultant cranial shape as well as patient education.