Risk factors associated with periprosthetic joint infection after total elbow arthroplasty.

BACKGROUND: For patients undergoing total elbow arthroplasty (TEA), the present study aimed to investigate: (i) what risk factors are associated with periprosthetic elbow infection; (ii) what is the incidence of infection after TEA; and (iii) what is the acuity with which these infections present? METHODS: The Statewide Planning and Research Cooperative System database was used to identify all patients who underwent TEA between 2003 and 2012 in New York State. Admissions for prosthetic joint infection (PJI) were identified using ICD-9 (International Classification of Diseases, Ninth Revision, Clinical Modification) diagnosis code 996.66. Multivariate analysis was used to determine risk factors that were independently prognostic for PJI. RESULTS: Significant risk factors for PJI included hypothyroidism [odds ratio (OR) = 2.04; p = 0.045], tobacco use disorder (OR = 3.39; p = 0.003) and rheumatoid arthritis (OR = 3.31; p < 0.001). Among the 1452 patients in the study period who underwent TEA, 3.7% (n = 54) were admitted postoperatively for PJI. There were 30 (56%) early infections, 17 (31%) delayed infections and seven (13%) late infections. CONCLUSIONS: Pre-operative optimization of thyroid function, smoking cessation and management of rheumatoid disease may be considered in surgical candidates for TEA. The results of the present study add prognostic data to the literature that may be helpful with patient selection and risk profile analysis. LEVEL OF EVIDENCE: Level III: prognostic study.

Protocol-Driven Revision for Stiffness After Total Knee Arthroplasty Improves Motion and Clinical Outcomes.

BACKGROUND: Stiffness after revision total knee arthroplasty (TKA) is a difficult problem without a well-defined treatment algorithm. The purpose of this study was to evaluate the results of revision TKA for stiffness within the context of differential component replacement. METHODS: Consecutive patients who underwent revision TKA were retrospectively identified and included those who received debridement and polyethylene liner exchange alone, revision of only one of the femoral or tibial fixed components, or revision of all components. Preoperative and postoperative range of motion and Knee Society score (KSS) were collected. RESULTS: Sixty-nine knees were included in the study group with a mean follow-up of 43 months (range, 12-205 months). The mean prerevision flexion contracture of 17° improved to 5° after surgical intervention (P < .001). Similarly, mean flexion and motion arc improved from 70° to 92° and from 53° to 87°, respectively (P < .001). Mean KSS knee scores improved from 42 to 70 and KSS function scores improved from 41 to 68 (P < .001). Mean arc of motion improved by 45° in patients who underwent complete component revision, 32° with component retention, and 29° with single component revision (P = .046). KSS knee scores improved by 34, 25, and 28 points in these respective groups (P = .049). KSS function scores improved by 33, 27, and 25 points (P = .077). CONCLUSION: Revision surgery with or without component revision can improve motion and function in patients with stiffness after TKA. Complete component revision may offer the largest improvements in these outcome measures in properly selected patients.

Intra-abdominal migration of a k-wire during revision total hip arthroplasty.

Revision total hip arthroplasty in the setting of severe acetabular bone loss is a challenging problem that is becoming more common. Kirschner wires are often used during acetabular revision for temporary fixation of trial components. We describe an intraoperative migration of a Kirschner wire through the acetabulum into the peritoneal cavity, requiring acute laparoscopic removal.

Economic evaluation of access to musculoskeletal care: the case of waiting for total knee arthroplasty.

BACKGROUND: The projected demand for total knee arthroplasty is staggering. At its root, the solution involves increasing supply or decreasing demand. Other developed nations have used rationing and wait times to distribute this service. However, economic impact and cost-effectiveness of waiting for TKA is unknown. METHODS: A Markov decision model was constructed for a cost-utility analysis of three treatment strategies for end-stage knee osteoarthritis: 1) TKA without delay, 2) a waiting period with no non-operative treatment and 3) a non-operative treatment bridge during that waiting period in a cohort of 60 year-old patients. Outcome probabilities and effectiveness were derived from the literature. Costs were estimated from the societal perspective with national average Medicare reimbursement. Effectiveness was expressed in quality-adjusted life years (QALYs) gained. Principal outcome measures were average incremental costs, effectiveness, and quality-adjusted life years; and net health benefits. RESULTS: In the base case, a 2-year wait-time both with and without a non-operative treatment bridge resulted in a lower number of average QALYs gained (11.57 (no bridge) and 11.95 (bridge) vs. 12.14 (no delay). The average cost was $1,660 higher for TKA without delay than wait-time with no bridge, but $1,810 less than wait-time with non-operative bridge. The incremental cost-effectiveness ratio comparing wait-time with no bridge to TKA without delay was $2,901/QALY. When comparing TKA without delay to waiting with non-operative bridge, TKA without delay produced greater utility at a lower cost to society. CONCLUSIONS: TKA without delay is the preferred cost-effective treatment strategy when compared to a waiting for TKA without non-operative bridge. TKA without delay is cost saving when a non-operative bridge is used during the waiting period. As it is unlikely that patients waiting for TKA would not receive non-operative treatment, TKA without delay may be an overall cost-saving health care delivery strategy. Policies aimed at increasing the supply of TKA should be considered as savings exist that could indirectly fund those strategies.

Custom intramedullary intercalating device for treatment of supracondylar fracture between constrained total knee arthroplasty and well-fixed total hip arthroplasty.

Management of periprosthetic fractures between ipsilateral total knee arthroplasty (TKA) and total hip arthroplasty (THA) is difficult, and is further complicated in the setting of poor femoral bone stock. We present a case of supracondylar fracture between THA and long-stemmed TKA femoral components in a patient with rheumatoid arthritis, deficient metaphyseal bone stock, and recurrent fractures. A long custom intramedullary intercalating component was devised to link the well-fixed existing THA stem to a revision distal femoral component. The resulting construct was stable and allowed for full weight-bearing ambulation, representing a useful treatment option in the management of periprosthetic fractures between revision TKA and well-fixed THA.

Massive or 2-tendon rotator cuff tears in active patients with minimal glenohumeral arthritis: clinical and radiographic outcomes of reconstruction using dermal tissue matrix xenograft.

BACKGROUND: The management of irreparable massive or full-thickness 2-tendon rotator cuff tears in active patients with minimal glenohumeral arthritis remains a difficult challenge for the treating surgeon. Many different treatment options, with varied success, have been proposed. HYPOTHESES: (1) Patients undergoing reconstruction of irreparable massive or full-thickness 2-tendon rotator cuff tears by dermal tissue matrix xenograft would demonstrate improvements in pain, range of motion, strength, and subjective functional outcomes. (2) Postoperative ultrasonography would demonstrate intact repairs at a minimum 2-year follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-six patients (27 shoulders) underwent reconstruction of irreparable massive or full-thickness 2-tendon rotator cuff tears by dermal tissue matrix xenograft. Pain level (scale 0-10, 10 = severe pain), active range of motion, and supraspinatus and external rotation strength were assessed. Subjective outcome measures included American Shoulder and Elbow Score (ASES) and Short Form-12 (SF-12) score. Clinical and radiographic analyses were performed at an average 32-month follow-up period (minimum 2-year follow-up). Ultrasound imaging (static and dynamic) of the operative shoulder was performed at final follow-up to assess the integrity of the construct. RESULTS: Mean patient age was 60 years. Mean pain level decreased from 5.1 to 0.4 (P = .002). Mean active forward flexion and abduction improved from 138.8° to 167.3° (P = .024) and 117.9° to 149.3° (P = .001), respectively. Supraspinatus and external rotation strength improved from 7.2 to 9.4 (P = .001) and 7.4 to 9.5 (P = .001), respectively. Mean ASES improved from 62.7 to 91.8 (P = .0007), and mean SF-12 scores improved from 48.4 to 56.6 (P = .044). Twenty-one patients (22 shoulders) returned for a dynamic and static ultrasound of the operative shoulder at a minimum 2-year follow-up. Sixteen patients (73%) demonstrated a fully intact tendon-graft reconstruction, 5 patients (22%) had a partially intact reconstruction, and 1(5%) had a complete tear at the graft-bone interface caused by suture anchor pullout as a result of a fall. There were no cases of infection or tissue rejection. CONCLUSION: Active patients with massive or 2-tendon rotator cuff tears with minimal glenohumeral arthritis continue to be a subset of the population for whom there is no current standard of care. Results suggest that the use of porcine xenograft may be an effective means by which to treat these patients.

The withdrawn ASR™ THA and hip resurfacing systems: how have our patients fared over 1 to 6 years?

BACKGROUND: The Articular Surface Replacement™ (ASR™) metal-on-metal hip arthroplasty system (DePuy Orthopaedics, Inc, Warsaw, IN, USA) reportedly has a higher than anticipated early failure rate leading to a voluntary recall. This prompted us to evaluate all ASR™ components implanted at our center. QUESTIONS/PURPOSES: In all ASR™ components, we reported (1) revision rate, (2) blood metal ion levels, and (3) intraoperative findings for revisions related to adverse reaction to metal debris (ARMD). METHODS: We retrospectively reviewed all 172 patients (190 hips) who underwent THA (149 hips) or hip resurfacing (41 hips) with the ASR™ system. We determined failure rates. We obtained blood metal ion concentrations from 93 patients at last followup. We evaluated MRI studies and intraoperative histopathology. Minimum followup was 12 months (mean, 40 months; range, 12-74 months). RESULTS: At latest followup, we had revised 24 of 190 hips (13%): in 18 patients with THA and five patients with resurfacing. Mean time to revision was 45 months (range, 12-75 months). Mean blood concentrations were 13 µg/L (range, 0-150 µg/L) for cobalt and 6 µg/L (range, 0-87 µg/L) for chromium. Mean prerevision blood metal ion levels were higher in the revised group (cobalt: 48 µg/L; chromium: 18 µg/L) than in the nonrevised group (cobalt: 5 µg/L; chromium: 2 µg/L). ARMD was present in 14 of the 24 hips revised in this study. CONCLUSIONS: Surgeons must have a low threshold for concern for ARMD in patients with ASR™ systems. Blood metal ion levels and MRI can be used to evaluate patients with underperforming implants. Intraoperative histopathologic analysis and joint fluid cytology can help diagnose ARMD at the time of revision. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Creation of a femoral cortical window to facilitate total hip arthroplasty in patients with sickle cell hemoglobinopathies.

Patients with sickle cell hemoglobinopathies often have femoral head osteonecrosis with collapse, and can benefit greatly from total hip arthroplasty. However, numerous procedural challenges and perioperative complications make these cases difficult. More specifically, femoral canal preparation and proper component placement can be particularly challenging due to focal medullary sclerosis caused by repeated vascular insults to the bone. This study describes the creation of an anterior metaphyseal cortical bone window to aid in identification of the true femoral canal and to facilitate femoral component implantation.

Total knee arthroplasty in osteopetrosis using patient-specific instrumentation.

Osteopetrosis is an uncommon endocrine disease characterized by defective osteoclast resorption of bones. This causes a hard, sclerotic, and brittle bone throughout the skeleton. Fractures and unforgiving subchondral bone are common in this condition, both of which can lead to osteoarthritis. Total knee arthroplasty is often the treatment of choice but presents challenges due to the hard and sclerotic bone present throughout the metaphysis and diaphysis of the femur and the tibia. We present a case of knee osteoarthritis in a patient with osteopetrosis who underwent total knee arthroplasty using patient-specific instrumentation. This technique eliminates intramedullary alignment and minimizes drilling, reaming, and saw passes, making it attractive in the setting of diseases such as osteopetrosis to decrease operative time and potential complications.

Dermal tissue allograft for the repair of massive irreparable rotator cuff tears.

BACKGROUND: Massive irreparable rotator cuff tears in patients without advanced glenohumeral arthritis can pose a challenge to surgeons. Numerous management strategies have been utilized, and studies have shown varied results with regard to shoulder pain, range of motion, strength, and overall function. HYPOTHESIS: Patients undergoing repair of massive irreparable rotator cuff tears through a mini-open approach with the use of human dermal tissue matrix allograft would demonstrate an improvement in pain, range of motion, strength, and subjective functional outcomes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We performed a prospective observational study of 24 patients who underwent interposition repair of massive rotator cuff tears using human dermal allograft. All patients were evaluated preoperatively and postoperatively by the treating surgeon. Data were collected preoperatively and postoperatively for an average 3-year follow-up period (range, 29-40 months). Active range of motion as well as supraspinatus and infraspinatus strength was assessed. Subjective outcome measures included pain level (visual analog scale of 0-10, with 10 = severe pain), American Shoulder and Elbow Score (ASES), and Short-Form 12 (SF-12) score. Imaging evaluation to assess for repair integrity was performed using static and dynamic ultrasonography at final follow-up. RESULTS: Mean pain level decreased from 5.4 to 0.9 (P = .0002). Mean active forward flexion and external rotation motion improved from 111.7° to 157.3° (P = .0002) and from 46.2° to 65.1° (P = .001), respectively. Mean shoulder abduction improved from 105.0° to 151.7° (P = .0001). Supraspinatus and infraspinatus strength improved from 7.2 to 9.4 (P = .0003) and from 7.8 to 9.3 (P = .002), respectively. Mean ASES improved from 66.6 to 88.7 (P = .0003). Mean SF-12 scores improved from 48.8 to 56.8 (P = .03). One partial graft retear occurred because of patient noncompliance during postoperative rehabilitation. However, this patient still demonstrated improvement in pain, motion, and subjective outcomes at final follow-up. Ultrasonography demonstrated "fully intact" repairs in 76% of patients. All remaining patients had "partially intact" repairs. There were no complete tears. CONCLUSION: In our series of carefully selected candidates, all patients demonstrated a significant improvement in pain, range of motion, and strength. Subjective outcome measures, including mean ASES and SF-12 scores, also demonstrated significant improvement at an average 3-year follow-up.

Role of diabetes type in perioperative outcomes after hip and knee arthroplasty in the United States.

The objective of this study was to determine whether the type of diabetes mellitus (DM) affected the incidence of immediate perioperative complications following joint replacement. From 1988 to 2003, the Nationwide Inpatient Sample recognized 65,769 patients with DM who underwent total hip and knee arthroplasty in the United States. Bivariate and multivariate analyses compared patients with type 1 (n = 8728) and type 2 (n = 57,041) DM regarding common perioperative complications, mortality, and hospital course alterations. Type 1 DM patients had increased length of stays and inflation-adjusted costs after surgery (p < .001). Type 1 patients also had significant increases in the incidence of myocardial infarction, pneumonia, urinary tract infection, postoperative hemorrhage, wound infection, and death (p < .02). Perhaps because of the differences in the duration of disease and their underlying pathologies, patients with type 1 diabetes carry more significant overall perioperative risks and require more health care resources compared with patients with type 2 diabetes following hip and knee arthroplasty.

ARRB1-mediated regulation of E2F target genes in nicotine-induced growth of lung tumors.

BACKGROUND: Nicotine induces the proliferation of non-small cell lung cancer (NSCLC) cells via nicotinic acetylcholine receptors and the arrestin, ß1 (ARRB1) protein. However, whether ARRB1 translocates to the nucleus upon nicotinic acetylcholine receptor activation and how it regulates growth of human NSCLCs are not known. METHODS: We investigated nuclear localization of ARRB1 in human NSCLC cell lines (A549 and H1650), normal lung cell lines (NHBE and SAEC), and lung cancer tissue microarray. A549 cells were transfected with ARRB1-specific short hairpin RNA (A549-sh) to knockdown ARRB1 expression, or with empty vector (A549-EV), to examine the role of ARRB1 in the mitogenic and antiapoptotic effects of nicotine, binding of ARRB1 to E2F transcription factors, and the role of ARRB1 in nicotine-induced expression of E2F-regulated survival and proliferative genes cell division cycle 6 homolog (CDC6), thymidylate synthetase (TYMS), and baculoviral IAP repeat-containing 5 (BIRC5). Real-time polymerase chain reaction was performed for quantitative analysis of mRNA expression. Chromatin immunoprecipitation assays were performed on A549 cells and fresh-frozen human NSCLC tumors (n = 8) to examine the binding of ARRB1, E1A binding protein (EP300), and acetylated histone 3 (Ac-H3) on the E2F-regulated genes. All statistical tests were two-sided. RESULTS: Nicotine induced the nuclear translocation of ARRB1 in NSCLC and normal lung cells, and lung tumor tissues from smokers showed an increased nuclear localization. The mitogenic and antiapoptotic effects of nicotine were reduced in A549-sh cells. Nuclear ARRB1 bound to E2F transcription factors in normal lung cells, NSCLC cells, and tumors. Nicotine treatment induced a statistically significant increased expression of E2F-regulated genes in A549-EV but not in A549-sh cells; the maximum difference being observed in BIRC5 (A549-EV vs A549-sh, mean fold-increase in mRNA level upon nicotine treatment = 20.7-fold, 95% confidence interval = 19.2- to 22.2-fold, vs mean = 0.8-fold, 95% confidence interval= 0.78- to 0.82-fold, P < .001). Furthermore, nicotine induced the binding of ARRB1, EP300, and Ac-H3 on E2F-regulated genes. CONCLUSION: Nicotine induced the nuclear translocation of ARRB1 and showed increased expression of proliferative and survival genes, thereby contributing to the growth and progression of NSCLCs.

TRIM28 mediates primer binding site-targeted silencing of Lys1,2 tRNA-utilizing retroviruses in embryonic cells.

Murine leukemia viruses (MLVs) and related retroelements are potently restricted in embryonic cells by postintegration transcriptional silencing, likely to protect the germ line from insertional mutagenesis. This silencing is in large part attributable to the presence of a nuclear repression complex, which targets a sequence element of the proviral DNA, the repressor-binding site. The repressor-binding site closely overlaps the tRNA primer binding site, a highly conserved sequence essential for virus replication and defining the site of initiation of DNA synthesis during reverse transcription. We have recently demonstrated that the cellular corepressor TRIM28 is recruited to the proline tRNA primer-binding site used by many MLVs and is required to mediate this silencing. Here, we show that TRIM28 is also required for the restriction of retroviruses using a completely distinct tRNA for the priming of their DNA synthesis, namely Lys-1,2 tRNA. These results generalize the role of TRIM28 in retroviral restriction and suggest that this system has evolved to restrict multiple retroviruses.