Extensile Acetabular Exposure for the Direct Anterior Approach to the Hip.

The direct anterior approach to the hip is immediately extensile for complex acetabular reconstruction including placement of augments, cages, and bone graft both on the outer and inner table of the iliac wing. This approach is also useful for exposure and removal of intrapelvic implants.

Extensile Femoral Exposure for the Direct Anterior Approach to the Hip.

The direct anterior approach to the hip is immediately extensile to access the entire femur for a wide range of conversion hip replacement and revision hip replacement scenarios. Multiple types of trochanteric osteotomies and complex procedures including proximal femoral replacement can be accomplished through extension of the direct anterior approach distally.

Proximal Femoral Replacement Using the Direct Anterior Approach to the Hip.

Proximal femoral replacement is the salvage procedure for the most severe hip arthroplasty problems. We presented a straightforward approach to this complex procedure using the direct anterior approach to the hip. This allows for accurate fluoroscopic confirmation of acetabular implant placement and direct comparison of leg lengths. It also allows the patient to be supine during the surgery which facilitates the anesthesia care of this challenging patient population.

Periprosthetic Fractures and Conversion Hip Replacement Using the Direct Anterior Approach to the Hip.

Periprosthetic fractures of the femur and the acetabulum around a hip replacement are unfortunately relatively common as is failed acetabular and hip fracture fixation. This chapter will detail the use of the direct anterior approach to the hip to manage periprosthetic fractures of the femur and the acetabulum. We will also address the use of the direct anterior approach to the hip for conversion hip replacement in cases of failed femoral and acetabular fracture fixation.

Extensile Direct Anterior Approach to the Hip for Severe Acetabular Defects.

Although total hip arthroplasty (THA) surgery is one of the most successful procedures in orthopaedics, the number of revision procedures is predicted to increase by 137% over the next two decades.1 Implant failure modes such as instability, infection, loosening, and wear are becoming more prevalent.2 Instability, infection, extensive bony defects, and soft-tissue damage are the most important concerns and complications associated with revision surgery. More than 50% of revisions involve the acetabular implant.2 Paprosky et al described a classification of acetabular defects that occur in cases of implant failure.3 Treating type 2 and 3 uncontained defects can be technically challenging because the surgeon has to use extensive reconstruction techniques to adequately restore the biomechanics of the hip, structural stability, and leg length. Furthermore, neurovascular structures can be in jeopardy when complex pelvic reconstructive procedures are being conducted. In an attempt to optimize the access to the pelvic bone, to minimize soft-tissue damage and to protect the pelvic neurovascular structures, we use an extensile anterior approach to the acetabulum. This approach has been described by Ganz et al to conduct periacetabular osteotomies (PAO).4,5 This approach uses the Smith Petersen interval and exposes the anterior column and the acetabulum along with its defects. To our knowledge, the approach has not been used or described yet to conduct complex reconstructive surgeries for extensive acetabular defects in THA. The following is a description of a modified extensile surgical technique for challenging acetabular defects that may be encountered in certain revision THA reconstructions, as well as certain primary THA. This is an enhanced technical description of a technique presented by these authors in a previously described series of 48 patients who underwent revision using these techniques.6.

Does Surgical Stabilization of Lateral Compression-type Pelvic Ring Fractures Decrease Patients' Pain, Reduce Narcotic Use, and Improve Mobilization?

BACKGROUND: Debate remains over the role of surgical treatment in minimally displaced lateral compression (Young-Burgess, LC, OTA 61-B1/B2) pelvic ring injuries. Lateral compression type 1 (LC1) injuries are defined by an impaction fracture at the sacrum; type 2 (LC2) are defined by a fracture that extends through the posterior iliac wing at the level of the sacroiliac joint. Some believe that operative stabilization of these fractures limits pain and eases mobilization, but to our knowledge there are few controlled studies on the topic. QUESTIONS/PURPOSES: (1) Does operative stabilization of LC1 and LC2 pelvic fractures decrease patients' narcotic use and lower their visual analog scale pain scores? (2) Does stabilization allow patients to mobilize earlier with physical therapy? METHODS: This retrospective study of LC1 and LC2 fractures evaluated patients treated definitively at one institution from 2007 to 2013. All patients treated surgically, all nonoperative LC2, and all nonoperative LC1 fractures with complete sacral injury were included. In general, LC1 or LC2 fractures with greater than 10 mm of displacement and/or sagittal/axial plane deformity on static radiographs were treated surgically. One hundred fifty-eight patients in the LC1 group (107 [of 697 screened] nonoperative, 51 surgical) and 123 patients in the LC2 group (78 nonoperative, 45 surgical) met inclusion criteria. The surgical and nonoperative groups were matched for fracture type. To account for differences between patients treated surgically and nonoperatively, we used propensity modeling techniques incorporating treatment predictors. Propensity scores demonstrated good overlap and were used as part of multiple variable regression models to account for selection bias between the surgically treated and nonoperative groups. Patient-reported pain scores and narcotic administration were tallied in 24-hour increments during the first 24 hours of hospitalization, at 48 hours after intervention, and in the 24 hours before discharge. Time from intervention to mobilization out of bed was recorded; intervention was defined as the date of definitive surgical intervention or the day the surgeon determined the patient would be treated without surgery. RESULTS: There was no difference in the narcotics distributed to any of the groups with the exception that the patients with surgically treated LC2 fractures used, on average (mean [95% confidence interval]) 40.2 (-72.9 to -7.6) mg morphine less at the 48-hour mark (p = 0.016). In general, there were no differences between the groups' pain scores. The surgically treated patients with LC1 fractures mobilized 1.7 (-3.3 to -0.01) days earlier (p = 0.034) than their nonoperative counterparts. There was no difference in the LC2 cohort in terms of time to mobilization between those treated with and without surgery. CONCLUSIONS: There were few differences in pain scores and morphine use between the surgical and nonoperative groups, and the differences observed likely were not clinically important. We found no evidence that surgical stabilization of certain LC1 and LC2 pelvic fractures improves patients' pain, decreases their narcotic use, and improves time to mobilization. A randomized trial of patients with similar fractures and similar degrees initial displacement would help remove some of the confounders present in this study. LEVEL OF EVIDENCE: Level III, therapeutic study.

Immediate weightbearing is safe after revision total hip arthroplasty for Vancouver B2/B3 periprosthetic femur fractures.

INTRODUCTION: Modular fluted, tapered stems provide a reliable treatment for Vancouver B2/B3 fractures. Historically, these patients had weightbearing restrictions postoperatively. Although full immediate postoperative weightbearing may provide benefits in this patient population, stem subsidence is a concern. QUESTIONS/PURPOSES: The objective of this study was to investigate the effect of post-operative weight-bearing status on stem subsidence in patients treated with modular tapered stems for Vancouver B2 and B3 periprosthetic fractures. We sought to answer two questions: (1) Does full immediate postoperative weightbearing after revision total hip arthroplasty for periprosthetic femur fracture lead to increased stem subsidence compared to protected weightbearing? (2) Is there a mortality difference between these two groups of patients with different weightbearing restrictions? METHODS: From 2009 to 2015 all patients who underwent revision for Vancouver B2/B3 fractures were made non-weightbearing (NWB) for six weeks postoperatively. After 2015, immediate weightbearing as tolerated (WBAT) was allowed postoperatively. We compared stem subsidence between immediate postoperative and final radiographs. Additionally, we performed a Kaplan-Meijer analysis with one-year mortality as an endpoint. RESULTS: The final cohort included forty-seven patients with an average follow-up of 254 days. The average stem subsidence was 1.0 mm (95 % CI, 0.5-1.5 mm) in the NWB cohort and 0.3 mm (95 % CI, 0-0.7 mm) in the WBAT cohort (P = 0.10). In our survivorship analysis, we noted no deaths in the WBAT cohort compared to 17 % mortality in the NWB cohort at the one-year timepoint. CONCLUSION: Allowing patients to weight bear immediately after revision does not increase stem subsidence. Further studies are needed to determine whether early weightbearing provides a mortality benefit.

Venous thromboembolism testing practices after orthopaedic trauma: prophylaxis regimen does not influence testing patterns.

Objectives: To determine venous thromboembolism (VTE) testing patterns in an orthopaedic trauma population and to evaluate for differences in VTE surveillance by prophylaxis regimen through a secondary analysis of the ADAPT trial. Design: Prospective randomized trial. Setting: Level I trauma center. Patients: Three hundred twenty-nine adult (18 years and older) trauma patients presenting with an operative extremity fracture proximal to the metatarsals/carpals or any pelvic or acetabular fracture requiring VTE prophylaxis. Intervention: VTE imaging studies recorded within 90 days post injury. Main Outcome Measurements: Percentage of patients tested for VTE were compared between treatment groups using Fisher's exact test. Subsequently, multivariable regression was used to determine patient factors significantly associated with risk of receiving a VTE imaging study. Results: Sixty-seven patients (20.4%) had VTE tests ordered during the study period. Twenty (29.9%) of these 67 patients with ordered VTE imaging tests had a positive finding. No difference in proportion of patients tested for VTE by prophylaxis regimen (18.8% on aspirin vs. 22.0% on LMWH, P = 0.50) was observed. Factors associated with increased likelihood of VTE testing included White race (adjusted odds ratio [aOR]: 2.61, 95% CI: 1.26-5.42), increased Injury Severity Score (aOR for every 1-point increase: 1.10, 95% CI: 1.05-1.15), and lower socioeconomic status based on the Area Deprivation Index (aOR for every 10-point increase: 1.14, 95% CI: 1.00-1.30). Conclusions: VTE surveillance did not significantly differ by prophylaxis regimen. Patient demographic factors including race, injury severity, and socioeconomic status were associated with differences in VTE surveillance. Level of Evidence: Level I, Therapeutic.

The Role of Dual-Mobility Components in Total Hip Arthroplasty.

➤: Dual mobility (DM) refers to a now widely available option for total hip articulation. DM implants feature a small inner head, a hard bearing, that connects via a taper fit onto the femoral trunnion. This head freely rotates but is encased inside a larger, outer polyethylene head that articulates with a smooth acetabular component. ➤: DM acetabular components are available in the form of a monoblock shell or as a liner that is impacted into a modular shell, providing a metal articulation for the polyethylene outer head. ➤: DM is designed to increase hip stability by providing the arthroplasty construct with a higher jump distance, head-to-neck ratio, and range of motion prior to impingement. ➤: The use of DM in total hip arthroplasty continues to increase in the United States for both primary and revision arthroplasty. Surgeons should be aware of the potential benefits and pitfalls. ➤: Long-term data are lacking, especially for modular DM implants. Points of concern include a potential for accelerated polyethylene wear, intraprosthetic dislocation, and modular backside fretting corrosion.

Outcomes of Tibiotalocalcaneal Hindfoot Fusion Nails Used for Acute Lower Extremity Trauma in a High-Risk Patient Population.

OBJECTIVE: To determine the outcomes of high-risk patients treated with tibiotalocalcaneal hindfoot fusion nails. DESIGN: Retrospective case series. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Between January 2007 and December 2016, 50 patients with significant medical comorbidities treated with a tibiotalocalcaneal hindfoot fusion nail in the setting of acute distal tibia and ankle trauma considered to be limb-threatening. INTERVENTION: Tibiotalocalcaneal hindfoot fusion nail. MAIN OUTCOME MEASUREMENTS: Two-year cumulative incidence of unplanned reoperation and estimated survival with limb salvage at 2 years. RESULTS: Of the 50 patients, 20 (38%) had an unplanned reoperation (mean: 2.5 reoperations), including 19 for implant removal, 11 for irrigation and debridement and/or placement of an antibiotic delivery device, and 4 for revision fusion. Three patients required amputation and 3 patients died within 2 years of injury, resulting in an estimated survival with limb salvage at 2 years of 79% (95% confidence interval: 67%-91%). After accounting for the competing risk of death and incomplete follow-up, the 2-year cumulative incidence of unplanned reoperation was 64% (95% confidence interval: 62%-67%). CONCLUSIONS: Patients in this series experienced a high rate of return to the operating room but a relatively low rate of amputation. Because patients were indicated for this course of treatment on the basis of comorbidities felt to put them at high risk of loss of limb with traditional treatment, acute hindfoot fusion nailing might represent a viable option in select high-risk patients and injuries. Clinicians should be aware that complications are still common. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Proximal femoral replacement using the direct anterior approach to the hip.

OBJECTIVE: Proximal femoral replacement (PFR) is a salvage procedure originally developed for reconstruction after resection of sarcomas and metastatic cancer. These techniques can also be adapted for the treatment of non-oncologic reconstruction for cases involving massive proximal bone loss. The direct anterior approach (DAA) is readily utilized for revision total hip arthroplasty (THA), but there have been few reports of its use for proximal femoral replacement. INDICATIONS: Aseptic, septic femoral implant loosening, periprosthetic femoral fracture, oncologic lesions of the proximal femur. The most common indication for non-oncologic proximal femoral placement is a severe femoral defect Paprosky IIIB or IV. CONTRAINDICATIONS: Infection. SURGICAL TECHNIQUE: In contrast to conventional DAA approaches and extensions, we recommend starting the approach 3 cm lateral to the anterior superior iliac spine and performing a straight incision directed towards the fibular head. After identification and incision of the tensor fasciae lata proximally and the lateral mobilization of the iliotibial tract distally, the vastus lateralis muscle can be retracted medially as far as needed. Special care should be taken to avoid injuries to the branches of the femoral nerve innervating the vastus lateralis muscle. If required, the distal extension of the DAA can continue all the way to the knee to allow implantation of a total femoral replacement. The level of the femoral resection is detected with an x­ray. In accordance with preoperative planning, the proximal femur is resected. Ream and broach the distal femoral fragment to the femoral canal. With trial implants in place, leg length, anteversion of the implant and hip stability are evaluated. It is crucial to provide robust reattachment of the abductor muscles to the PFR prosthesis. Mesh reinforcement can be used to reinforce the muscular attachment if necessary. POSTOPERATIVE MANAGEMENT: We typically use no hip precautions other than to limit combined external rotation and extension for 6 weeks. In most cases, full weight bearing is possible after surgery. RESULTS: A PFR was performed in 16 patients (mean age: 55.1 years; range 17-84 years) using an extension of the DAA. The indication was primary bone sarcoma in 7 patients, metastatic lesion in 6 patients and massive periprosthetic femoral bone loss in 3 patients. Complications related to the surgery occurred in 2 patients (both were dislocation). Overall, 1 patient required reoperation and 1 patient died because of his disease. Mean follow-up was 34.5 months.

Open reduction and internal fixation alone versus open reduction and internal fixation plus total hip arthroplasty for displaced acetabular fractures in patients older than 60 years: A prospective clinical trial.

INTRODUCTION: The optimal treatment of elderly patients with an acetabular fracture is unknown. We conducted a prospective clinical trial to compare functional outcomes and reoperation rates in patients older than 60 years with acetabular fracture treated with open reduction and internal fixation (ORIF) alone versus ORIF plus concomitant total hip arthroplasty (ORIF + THA). Our hypothesis was that patients who had ORIF + THA would have better patient reported outcomes and lower reoperation rates postoperatively. METHODS: Inclusion criteria were patients older than 60 years with acetabular fracture plus at least one of three fracture characteristics: dome impaction, femoral head fracture, or posterior wall component. Eligible patients were operative candidates based on fracture displacement, ambulatory status, and physiological appropriateness. Patients received either ORIF alone or ORIF + THA (accomplished at same surgery through same incision). Outcome measurements included Western Ontario and McMaster Universities Osteoarthritis Index hip score, Short Form 36, Harris Hip Score, and Patient Satisfaction Questionnaire Short Form scores. Additionally, patients were monitored for any unplanned reoperation within 2 years. RESULTS: Forty-seven of 165 eligible patients with an average age of 70.7 years were included. The mean Harris Hip Score difference favored ORIF + THA (mean difference, 12.3, [95% confidence interval (CI), -0.3 to 24.9, p = 0.07]). No clinically important differences were detected in any other validated outcome score or patient satisfaction score 1 year after surgery. ORIF + THA decreased the absolute risk of reoperation by 28% (95% CI, 13% to 44%, p < 0.01). No postoperative hip dislocation occurred in either group. CONCLUSIONS: In patients older than 60 years with an operative displaced acetabular fracture with specific fracture features (dome impaction, femoral head fracture, or posterior wall component), treatment with ORIF + THA resulted in fewer reoperations than treatment with ORIF alone. No differences in patient satisfaction and other validated outcome measures were detected.

Pelvic Ring Injury Mortality: Are We Getting Better?

OBJECTIVES: To determine if changes in pelvic trauma care and treatment protocols have affected overall mortality rates after pelvic ring injury. DESIGN: Retrospective cohort study. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: A total of 3314 patients with pelvic ring injuries who presented to a single referral center from 1999 to 2018 were included in the study. INTERVENTION: Pelvic ring management, years 1999-2006 versus years 2007-2018. MAIN OUTCOME MEASUREMENTS: In hospital mortality. Other examined variables included change in patient demographics, fracture characteristics, date of injury, associated injuries, length of hospital stay, Abbreviated Injury Severity Score. RESULTS: The composite mortality rate was 6.5% (214/3314). The earliest cohort presented a mortality rate of 9.1% [111/1224; 95% confidence interval (CI), 7.6%-10.8%] compared with the more recent cohort mortality rate of 4.9% (103/2090; 95% CI, 4.1%-5.9%). Overall mortality was significantly lower in the more recent period, a risk difference of 4.1% (95% CI, 2.3%-6.1%; P < 0.01). After adjusting for age and Abbreviated Injury Severity Score of the brain, chest, and abdomen, the mortality reduction was more pronounced with an adjusted risk difference of 6.4% (95% CI, 4.7%-8.1%; P < 0.01). CONCLUSION: Significant improvement in the mortality rate of pelvic ring injuries has been demonstrated in recent years (4.9% vs. 9.1%) and the difference is even large when accounting for known confounders. Improvement appears to coincide chronologically with changes in trauma resuscitation and implementation of adjuvant treatments for managing patients with severe hemorrhagic shock. Although the exact benefit of each treatment awaits further research, these data might indicate improved care over time for these difficult patients. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Poor Agreement Between Next-Generation DNA Sequencing and Bacterial Cultures in Orthopaedic Trauma Procedures.

BACKGROUND: Next-generation DNA sequencing (NGS) detects bacteria-specific DNA corresponding to the 16S ribosomal RNA gene and can identify bacterial presence with greater accuracy than traditional culture methods. The clinical relevance of these findings is unknown. The purpose of the present study was to compare the results from bacterial culture and NGS in order to characterize the potential use of NGS in orthopaedic trauma patients. METHODS: A prospective cohort study was performed at a single academic, level-I trauma center. Three patient groups were enrolled: (1) patients undergoing surgical treatment of acute closed fractures (presumed to have no bacteria), (2) patients undergoing implant removal at the site of a healed fracture without infection, and (3) patients undergoing a first procedure for the treatment of a fracture nonunion who might or might not have subclinical infection. Surgical site tissue was sent for culture and NGS. The proportions of culture and NGS positivity were compared among the groups. The agreement between culture and NGS results was assessed with use of the Cohen kappa statistic. RESULTS: Bacterial cultures were positive in 9 of 111 surgical sites (110 patients), whereas NGS was positive in 27 of 111 surgical sites (110 patients). Significantly more cases were positive on NGS as compared with culture (24% vs. 8.1%; p = 0.001), primarily in the acute closed fracture group. No difference was found in terms of the percent positivity of NGS when comparing the acute closed fracture, implant removal, and nonunion groups. With respect to bacterial identification, culture and NGS agreed in 73% of cases (κ = 0.051; 95% confidence interval, -0.12 to 0.22) indicating only slight agreement compared with expected chance agreement of 50%. CONCLUSIONS: NGS identified bacterial presence more frequently than culture, but with only slight agreement between culture and NGS. It is possible that the increased frequency of bacterial detection with molecular methods is reflective of biofilm presence on metal or colonization with nonpathogenic bacteria, as culture methods have selection pressure posed by restrictive, artificial growth conditions and there are low metabolic activity and replication rates of bacteria in biofilms. Our data suggest that NGS should not currently substitute for or complement conventional culture in orthopaedic trauma cases with low suspicion of infection. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Inpatient compliance with venous thromboembolism prophylaxis after orthopaedic trauma: results from a randomized controlled trial of aspirin versus low molecular weight heparin.

OBJECTIVES: To compare inpatient compliance with venous thromboembolism prophylaxis regimens. DESIGN: A secondary analysis of patients enrolled in the ADAPT (A Different Approach to Preventing Thrombosis) randomized controlled trial. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Patients with operative extremity or any pelvic or acetabular fracture requiring venous thromboembolism prophylaxis. INTERVENTION: We compared patients randomized to receive either low molecular weight heparin (LMWH) 30 mg or aspirin 81 mg BID during their inpatient admission. MAIN OUTCOME MEASUREMENTS: The primary outcome measure was the number of doses missed compared with prescribed number of doses. RESULTS: A total of 329 patients were randomized to receive either LMWH 30 mg BID (164 patients) or aspirin 81 mg BID (165 patients). No differences observed in percentage of patients who missed a dose (aspirin: 41.2% vs LMWH: 43.3%, P = .7) or mean number of missed doses (0.6 vs 0.7 doses, P = .4). The majority of patients (57.8%, n = 190) did not miss any doses. Missed doses were often associated with an operation. CONCLUSIONS: These data should reassure clinicians that inpatient compliance is similar for low molecular weight heparin and aspirin regimens.

Patient Satisfaction After Discharge Is Discordant With Reported Inpatient Experience.

Patient satisfaction measures are commonly used to evaluate clinical performance. However, research on the correlation between patient satisfaction scores and actual patient experience is limited. This study aimed to determine the concordance between patient satisfaction reported as an inpatient and patient satisfaction reported after discharge. The study enrolled 231 adult orthopedic patients at least 48 hours after admission to an academic hospital. Study participants rated their overall inpatient experience on a scale of 0 to 10, followed by open-ended questions on their hospital experience. Participants were then randomized to a second survey by either phone or mail at 4 to 6 weeks after discharge. Statistical and qualitative techniques were used to assess concordance in satisfaction scores and the agreement and association between patient experiences and patient satisfaction scores. The median overall patient satisfaction scores were 9.5 as inpatients (interquartile range [IQR], 8-10) and 10 at follow-up (IQR, 8-10), with a poor concordance between the inpatient and follow-up satisfaction scores (ρc=0.28). This study raises concerns regarding the validity of patient satisfaction measures to accurately quantify inpatient experience and the limitations related to its modes of administration. The authors observed poor agreement between the reported experience as an inpatient and the recollection of the inpatient experience after discharge. [Orthopedics. 2021;44(3):e427-e433.].

A Prospective Clinical Trial Comparing Surgical Fixation Versus Nonoperative Management of Minimally Displaced Complete Lateral Compression Pelvis Fractures.

OBJECTIVE: To compare the early pain and functional outcomes of operative fixation versus nonoperative management for minimally displaced complete lateral compression (LC; OTA/AO 61-B1/B2) pelvic fractures. DESIGN: Prospective clinical trial. SETTING: Two academic trauma centers. PATIENTS: Forty-eight adult patients with LC pelvic ring injuries with <10 mm of displacement were treated nonoperatively and 47 with surgical fixation. Sixty percent of participants were randomized. Seventy-three percent of the fractures were displaced <5 mm, and 71% were LC-1 patterns. INTERVENTION: Operative fixation versus nonoperative management. MAIN OUTCOME MEASUREMENTS: The primary outcome was patient-reported pain using the 10-point Brief Pain Inventory. Functional outcome was measured using the Majeed pelvic score. Outcomes were analyzed using hierarchical Bayesian models to compare the average treatment effect from injury to 12 and 52 weeks postinjury. The probability of the mean treatment benefit exceeding a clinically important difference was determined. RESULTS: The 3-month average treatment effect of surgery compared with nonoperative management was a 1.2-point reduction in pain [95% credible interval (CrI): 0.4-1.9] and an 8% absolute improvement in the Majeed score (95% CrI: 3%-14%). Similar results persisted to 1 year. Patients with initial fracture displacement ≥5 mm experienced a larger reduction in pain (2.2, 95% CrI: 0.9-3.5) compared with those patients with less initial displacement (0.9, 95% CrI: 0.1-1.8). CONCLUSION: On average, surgical fixation likely provides a small improvement in pain and functional outcome for up to 12 months. Patients with ≥5 mm of posterior pelvic ring displacement are more likely to experience clinically important improvements in pain. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

PREVENTion of CLots in Orthopaedic Trauma (PREVENT CLOT): a randomised pragmatic trial protocol comparing aspirin versus low-molecular-weight heparin for blood clot prevention in orthopaedic trauma patients.

INTRODUCTION: Patients who sustain orthopaedic trauma are at an increased risk of venous thromboembolism (VTE), including fatal pulmonary embolism (PE). Current guidelines recommend low-molecular-weight heparin (LMWH) for VTE prophylaxis in orthopaedic trauma patients. However, emerging literature in total joint arthroplasty patients suggests the potential clinical benefits of VTE prophylaxis with aspirin. The primary aim of this trial is to compare aspirin with LMWH as a thromboprophylaxis in fracture patients. METHODS AND ANALYSIS: PREVENT CLOT is a multicentre, randomised, pragmatic trial that aims to enrol 12 200 adult patients admitted to 1 of 21 participating centres with an operative extremity fracture, or any pelvis or acetabular fracture. The primary outcome is all-cause mortality. We will evaluate non-inferiority by testing whether the intention-to-treat difference in the probability of dying within 90 days of randomisation between aspirin and LMWH is less than our non-inferiority margin of 0.75%. Secondary efficacy outcomes include cause-specific mortality, non-fatal PE and deep vein thrombosis. Safety outcomes include bleeding complications, wound complications and deep surgical site infections. ETHICS AND DISSEMINATION: The PREVENT CLOT trial has been approved by the ethics board at the coordinating centre (Johns Hopkins Bloomberg School of Public Health) and all participating sites. Recruitment began in April 2017 and will continue through 2021. As both study medications are currently in clinical use for VTE prophylaxis for orthopaedic trauma patients, the findings of this trial can be easily adopted into clinical practice. The results of this large, patient-centred pragmatic trial will help guide treatment choices to prevent VTE in fracture patients. TRIAL REGISTRATION NUMBER: NCT02984384.

Does fracture pattern predict death with lateral compression type 1 pelvic fractures?

BACKGROUND: Our goal was to analyze whether radiographic fracture pattern correlates with mortality of patients with lateral compression type 1 (LC1) fractures. METHODS: We conducted a retrospective case-controlled study at a Level I trauma center. Radiographs and outcome data were obtained for 52 patients with LC1 fractures who died and 63 who lived. LC1 fractures were classified by Denis zone of sacral injury and presence of fracture displacement. Our main outcome measurement was mortality during index hospital admission. RESULTS: No difference was observed in frequency of higher energy Denis zone II sacral fractures between patients with LC1 fractures who died (73.1%) and those who lived (69.8%, p = 0.86, χ²). No difference was observed in number of displaced fractures (50.0% vs. 34.9%, p = 0.15, χ²). Patients who died were more likely to have significant brain injury (69.2% vs. 14.2%, p < 0.0001, χ²), chest injury (73.1% vs. 49.2%, p < 0.05, χ²), or abdominal injury (30.8% vs. 9.5%, p < 0.05, χ²) than those who lived. CONCLUSION: Sacral fracture pattern does not seem to be predictive of mortality for patients with LC1 pelvic fractures The presence of associated injuries seems to be the key driver of mortality.

Unicondylar knee retrieval analysis.

Unicondylar knee arthroplasty (UKA) is considered an alternative to total knee arthroplasty for patients who have arthritis limited to one compartment of the knee. This study examined surface damage of 3 contemporary UKA designs that were retrieved at revision surgery. Two of the UKA designs were fixed bearing and one was mobile bearing. Demographic information was collected, as well as information about the implants used at revision surgery. Articular surface damage was greater in the fixed-bearing designs as compared to the mobile bearing, although the mobile-bearing implants had significantly shorter length of implantation. Backside damage was also graded for the mobile bearing and when combined with articular wear resulted in overall damage scores higher than both fixed-bearing designs. The fixed-bearing designs showed delamination and surface deformation, whereas the mobile bearing had no evidence of these damage modes. However, mobile-bearing components showed other types of wear, and significant wear damage was present on the bearing surfaces of the mobile-bearing implants despite a short time of implantation. At the time of conversion to a total knee arthroplasty, more than 50% of cases required the use of stems, augments, or constrained inserts for the tibial reconstruction. In conclusion, wear modes differed among UKA prosthesis designs. Revision of a UKA to a total knee arthroplasty remains complex with the tibial preparation more complicated than in the primary setting.