The pathophysiology of pelvic ring injuries: a review.

Traumatic pelvic ring injuries continue to represent a major challenge due to the high rates of post-injury mortality of around 30-40% in the peer-reviewed literature. The main root cause of potentially preventable mortality relates to the delayed recognition of the extent of retroperitoneal hemorrhage and post-injury coagulopathy. The understanding of the underlying pathophysiology of pelvic trauma is predicated by classification systems for grading of injury mechanism and risk stratification for developing post-injury coagulopathy with subsequent uncontrolled exsanguinating hemorrhage. This review article elaborates on the current understanding of the pathophysiology of severe pelvic trauma with a focus on the underlying mechanisms of retroperitoneal bleeding and associated adverse outcomes.

Minimally invasive femoral head fracture fixation using three-dimensional navigation: a technical note.

Femoral head fractures are rare traumatic injuries that are usually associated with hip dislocations. Open reduction and internal fixation are performed when indicated, but can be associated with a higher risk of avascular necrosis. We report the case of a 24-year-old patient with a Pipkin type II fracture dislocation of the femoral head fixed via a minimally invasive three-dimensional navigated internal fixation technique. This technique minimizes deep soft tissue dissection to the hip capsule and associated vascularity and allows for accurate implant positioning.Level of evidence: Therapeutic case report Level IV.

Trans-sacral screw fixation of posterior pelvic ring injuries: review and expert opinion.

Posterior pelvic ring injuries (i.e., sacro-iliac joint dislocations, fracture-dislocations, sacral fractures, pelvic non-unions/malunions) are challenging injury patterns which require a significant level of surgical training and technical expertise. The modality of surgical management depends on the specific injury patterns, including the specific bony fracture pattern, ilio-sacral joint involvement, and the soft tissue injury pattern. The workhorse for posterior pelvic ring stabilization has been cannulated iliosacral screws, however, trans-sacral screws may impart increased fixation strength. Depending on injury pattern and sacral anatomy, trans-sacral screws can potentially be more beneficial than iliosacral screws. In this article, the authors will briefly review pelvic mechanics and discuss their rationale for ilio-sacral and/or trans-sacral screw fixation.

A novel intramedullary nail to control interfragmentary motion in diaphyseal tibial fractures.

Numerous animal and human studies have demonstrated the benefit of controlled interfragmentary motion on fracture healing. In this study, we quantified interfragmentary motion and load transfer in tibial fractures fixed using a novel intramedullary nail (IMN) that allows controlled axial motion. Fifty composite tibias with various fracture patterns were utilized. For all test conditions, two interlocking screws were used to fix the nail in the proximal metaphysis, and two interlocking screws through the distal metaphysis. The nail allowed either no motion (static mode) or 1 mm (dynamic mode) of cyclic axial motion between the two fracture fragments for every fracture pattern tested. As expected, strain shielding was more prominent under static nail conditions. In contrast, specimens tested under dynamic nail conditions transferred axial load between the fracture fragments such that strains near the fracture site were generally similar to those measured on an intact tibia. Maximum shear strains proximal to the fracture were significantly lower in specimens with oblique or butterfly fracture patterns (p < 0.01) compared to intact specimens. This decrease in shear strain indicates that strain shielding effects were likely present due to the implant. However, strain shielding appeared to be reduced in tensile and compressive principal strains. In summary, the novel IMN allowed controlled axial motion between the fragments in a variety of common diaphyseal tibial fracture patterns. Clinical Significance: The present in vitro biomechanical study investigated a novel intramedullary nail capable of controlled axial interfragmentary motion which may potentially enhance fracture healing.

Outcomes after surgical treatment of acetabular fractures: a review.

Acetabular fractures are fractures that extend into the hip joint and pose a challenge for orthopaedic trauma surgeons. The first known descriptions of surgical fixation of acetabular fractures were case reports in 1943. In 1964, Robert Judet, Jean Judet, and Émile Letournel published a landmark article describing a classification system and surgical approaches to treat acetabular fractures. These teachings had a significant effect on clinical outcomes after surgical fixation of acetabular fractures. In 1980, Letournel demonstrated 80% good-to-excellent results in 492 hips, and in 2012, Joel Matta demonstrated 79% survivorship in 816 patients follow surgical acetabular fixation. Both Letournel and Matta have definitively shown that anatomic reduction of the fracture is the most influential factor predictive of clinical outcome. The intent of this review is to summarize the salient factors affecting clinical outcomes after surgical treatment of acetabular fractures.

Ten- and 20-year Survivorship of the Hip After Periacetabular Osteotomy for Acetabular Dysplasia.

INTRODUCTION: Acetabular dysplasia is a multifactorial condition characterized by a shallow hip socket with predisposition to osteoarthritis of the hip. The Bernese periacetabular osteotomy (PAO), developed by Reinhold Ganz in 1984, reorients the dysplastic hip joint to provide more uniform coverage of the femoral head and to extend the longevity of the native hip. Since 1987, the senior author performed the Bernese PAO on more than 430 patients. We performed a cross-sectional retrospective study on this cohort of patients to determine the 10- and 20-year survivorship after PAO in addition to assessing functional outcomes and radiographic parameters. METHODS: Four hundred thirty-four patients were treated for acetabular dysplasia with PAO by the senior surgeon from 1987 to 2014. Data were obtained for 302 hips in 258 patients in a retrospective fashion from medical records and/or mail-in/phone questionnaires. Functional outcome data consisted of postoperative Hip Osteoarthritis Outcome Score and University of California-Los Angeles Activity Score. Pre- and postoperative radiographs were used to determine lateral center-edge angle, anterior center-edge angle, Tönnis angle/grade, and head-to-ilioischial line distance. Survivorship of the native hip was determined by Kaplan-Meier analysis. RESULTS: Of the 302 hips analyzed, 248 were still surviving native hips and 54 had gone on to a total hip arthroplasty (THA) at the time of data acquisition. The average age of patients in the entire cohort at PAO was 32.7 years (range, 13 to 63 years). Of the 258 patients, 215 were female patients (83.3%) and 43 male patients (16.8%). The average age of patients in the surviving group at PAO was 32.3 years, and the average age of patients in the THA group was 36.6 years (P < 0.01). At the time of data acquisition, follow-up ranged from 2 to 27 years (average, 11.2 years). Hip Osteoarthritis Outcome Score and University of California-Los Angeles Activity Score are reported for the surviving native hips after PAO. Radiographic analyses for surviving and failed hips are described, with pre- and postoperative Tönnis grade being statistically significant predictors for conversion to THA (P < 0.01). Survivorship of the native hip was 86% at 10 years and 60% at 20 years in the surviving cohort. Survivorship stratified by age at the time of PAO demonstrated a 10-year survivorship of 93.3%, 90.1%, 81.6%, and 63.2% at ages 20, 30, 40, and 50 years, respectively. No notable difference exists in survivorship between male and female patients; however, male patients had a trend toward lower survivorship compared with female patients at 15 years. CONCLUSION: The 10- and 20-year survivorship of the native hip after PAO is approximately 86% and 60%, respectively, in our cohort of 302 hips. Older age at the time of PAO and higher Tönnis grade are negative prognostic factors for joint survival after PAO. Surviving hips after PAO have good functional outcomes even up to 20 years after surgery. This survivorship analysis represents one of the largest and longest survival studies of patients after PAO, and our results are consistent with other published studies. LEVEL OF EVIDENCE: Level III.

Is the Anterior Approach Safe? Early Complication Rate Associated With 5090 Consecutive Primary Total Hip Arthroplasty Procedures Performed Using the Anterior Approach.

BACKGROUND: Few publications have raised concern with the safety of the anterior approach (AA) to total hip arthroplasty (THA). The purpose of this study is to report the early complications with AA THA in a combined, multicenter patient population from three different institutions. METHODS: The study cohort consisted of 5090 consecutive primary procedures in 4473 patients who had undergone THA utilizing the anterior approach between August 2006 and July 2013. Surgeries were performed by five surgeons at three sites that maintain prospective databases. Preoperative, intraoperative, and postoperative data were recorded on all patients. Demographic data including age, gender, and BMI were queried, as well as all intraoperative and postoperative complications in the first 90 days. RESULTS: The 5090 patients had a mean body mass index of 27.5, and mean age of 63.6 years. The overall 90-day complication rate was 1.9%. There were 41 intraoperative femur fractures including 29 calcar fractures, 9 greater trochanter fractures and 3 femoral shaft fractures. There were 7 postoperative femur fractures including 3 greater trochanter fractures, 2 calcar fractures, and 2 femur fractures. Other complications included 15 superficial infections, 5 deep infections, 12 dislocations, 8 hematomas, 3 cases of cellulitis, 2 sciatic nerve palsies, 1 peroneal nerve palsy, and intrapelvic bleed. The nonsurgical complication rate was 1.4%. Deep vein thrombosis occurred in 0.3% of cases. CONCLUSION: This large multicenter study of consecutive AA THAs demonstrates an acceptable risk profile within the first 90 days after surgery.

Relationship Between the Superior Gluteal Vessels and Nerve at the Greater Sciatic Notch.

Bleeding from the superior gluteal (SG) blood vessels at the greater sciatic notch is frequently encountered during acetabular fracture surgery. The purpose of this study is to define the positional anatomy of the superior gluteal vessels and nerve (SGVAN) at the greater sciatic notch. Twenty-three hemipelvi were dissected in whole human cadavers. The greater sciatic notch and SGVAN were visualized via a posterior surgical approach, identified deep in the greater sciatic notch, and traced superficially. Branches of the SGVAN and their anatomical relationship to each other were recorded. In the notch, SG arteries comprised a single vessel in 18 (78%) of 23 specimens, with all of these dividing at varying distances (1-3.5 cm) along the lateral ilium after dividing into superior and inferior branches. The SG artery branches were contiguous with periosteum of the bony notch in all specimens. More than 1 SG nerve branch was seen in the greater sciatic notch of all specimens, including an inferior branch that exited caudal or caudal-superficial to the SG vessels. The caudal-most SG nerve branch was directly adjacent to the bony notch's periosteum in 15 (65%) of 23 specimens. The SGVAN are at risk in patients undergoing acetabular fracture surgery. Individuals performing surgery along the acetabulum's posterior column would expect to encounter a major SG nerve branch (deep inferior) before encountering the SG vessels in all cases. Iatrogenic injuries to the SGVAN might be prevented by avoiding use of cautery in this area if hemorrhage is encountered.

Safe surgical technique: iliac osteotomy via the anterior approach for revision hip arthroplasty.

Robert Judet first performed hip arthroplasty via the anterior approach (AA) in 1947 on an orthopaedic table. Our center has a near 20-year experience on more than 3500 patients operated by AA hip arthroplasty. While primary AA total hip arthroplasty techniques have been discussed in the literature, revision AA total hip arthroplasty techniques are relatively new. The current article in the Journal's "Safe Surgical Technique" series describes the successful application of an adjunctive iliac osteotomy to improve femoral exposure in two selected patients undergoing AA revision hip arthroplasty. The potential risk/complications of an iliac osteotomy include iatrogenic fracture, malunion/nonunion, infection, and pain. These potential risks should be weighed against the potential benefits of improved surgical exposure and/or risks of other revision techniques. Future prospective longitudinal studies will be helpful to determine efficacy and risk profile compared to other revision techniques.

The 'Ziran' wrap: reconstruction of critical-sized long bone defects using a fascial autograft and reamer-irrigator-aspirator autograft.

Reconstruction of critical-size bony defects remains a challenge to surgeons despite recent technological advances. Current treatments include distraction osteogenesis, cancellous autograft, induced membranes (Masquelet procedure), polymeric membranes, and titanium-mesh cages filled with bone graft. In this article, the authors presents two cases in which critical-sized defects were reconstructed using a meshed fascial autograft encasing reamer-irrigator-aspirator (RIA) autograft and cancellous allograft. This article will discuss the clinical outcomes of the technique, comparison to other current techniques, and technical insight into the potential biological mechanism.

Associated lateral process and posteromedial tubercle talus fractures:a case report and literature review.

This article describes the case of a 39-year-old man who sustained both a lateral process and posteromedial tubercle talus fracture. Both fractures were treated with open reduction and internal fixation resulting in a satisfactory clinical outcome. Although this combination of injuries has been described in the literature, this is the first reported case to describe surgical fixation of both fractures.

Femoral artery thrombosis after internal fixation of a transverse acetabular fracture in a patient with osteogenesis imperfecta type I.

Osteogenesis imperfecta is a genetic disorder characterized by increased susceptibility to fractures and vascular injuries due to connective tissue fragility. In this case report, we present a patient with osteogenesis imperfecta type I who sustained a transverse fracture of the right acetabulum while transferring from bed to chair. The fracture was repaired through an ilioinguinal approach. During the surgery, an iatrogenic injury to the femoral artery and vein occurred. This intraoperative complication was salvaged by immediate vascular repair. We discuss the possible causes of iatrogenic vascular injuries in patients with osteogenesis imperfecta. Orthopaedic surgeons should be aware of this potentially devastating complication in this particular patient cohort.

Onset, progression, and plateau of skeletal lesions in fibrous dysplasia and the relationship to functional outcome.

UNLABELLED: Most lesions in FD and their attendant functional disability occur within the first decade; 90% of lesions are present by 15 years, and the median age when assistive devices are needed is 7 years. These findings have implications for prognosis and determining the timing and type of therapy. INTRODUCTION: Fibrous dysplasia of bone (FD) is an uncommon skeletal disorder in which normal bone is replaced by abnormal fibro-osseous tissue. Variable amounts of skeletal involvement and disability occur. The age at which lesions are established, the pace at which the disease progresses, if (or when) the disease plateaus, and how these parameters relate to the onset of disability are unknown. To answer these questions, we performed a retrospective analysis of a group of subjects with FD. MATERIALS AND METHODS: One hundred nine subjects with a spectrum of FD were studied for up to 32 years. Disease progression was assessed in serial (99)Tc-MDP bone scans by determining the location and extent of FD lesions using a validated bone scan scoring tool. Physical function and the need for ambulatory aids were assessed. RESULTS: Ninety percent of the total body disease skeletal burden was established by age 15. Disease was established in a region-specific pattern; in the craniofacial region, 90% of the lesions were present by 3.4 yr, in the extremities, 90% were present by 13.7 yr, and in the axial skeleton, 90% were present by 15.5 yr. Twenty-five of 103 subjects eventually needed ambulatory aids. The median age at which assistance was needed was 7 yr (range, 1-43 yr). The median bone scan score for subjects needing assistance was 64.3 (range, 18.6-75) compared with 23.1 (range, 0.5-63.5) in the unassisted subjects (p < 0.0001). Among subjects needing assistance with ambulation, 92% showed this need by 17 yr. CONCLUSIONS: The majority of skeletal lesions and the associated functional disability occur within the first decade of life. The implication is that the window of time for preventative therapies is narrow. Likewise, therapeutic interventions must be tailored to where the patient is in the natural history of the disease (i.e., progressive disease [young] versus established disease [older subjects]). These findings have implications for prognosis, the timing and type of therapy, and the development of trials of new therapies and their interpretation.

Circulating connective tissue precursors: extreme rarity in humans and chondrogenic potential in guinea pigs.

Using a variety of cell separation techniques and cultivation conditions, circulating, adherent, connective tissue, clonogenic cells were found in just 3 donors out of 66, demonstrating that these precursors are extremely rare in postnatal human blood. Contrary to humans, guinea pig blood shows much more reproducible connective tissue colony formation; it was therefore chosen to study the differentiation potential of adherent blood-derived clonogenic cells. Out of 22 single colony-derived strains of various morphologies, only 5 spindle-shaped strains showed extensive proliferative capacity in vitro. None of these strains formed bone upon in vivo transplantation, whereas two strains formed cartilage in high-density pellet cultures in vitro. Both chondrogenic strains included cells expressing aggrecan, whereas nonchondrogenic strains did not. Out of four polyclonal strains studied, one formed both cartilage and abundant bone accompanied by hematopoiesis-supporting stroma. Evidently, there are cells in adult guinea pig blood capable of both extensive proliferation and differentiation toward cartilage: circulating chondrogenic precursors. Although some of these cells lack osteogenic potential and therefore represent committed chondrogenic precursors, others may be multipotential and consequently belong to the family of skeletal stem cells. This is the first demonstration of postnatal circulating chondrogenic precursors, as well as of precursor cells with chondrogenic but not osteogenic potential. Disclosure of potential conflicts of interest is found at the end of this article.

Repetitive posterior iliac crest autograft harvest resulting in an unstable pelvic fracture and infected non-union: case report and review of the literature.

Fractures of the pelvic ring have been well studied, and the biomechanical relationship between the anterior and posterior elements is an important concept to understand these complex injuries. The vast majority of these injuries are due to trauma. However, in rare circumstances, autogenous bone graft harvesting may lead to an unstable pelvic ring. In this case report, we describe a rare complication in a 70-year old female patient who developed an unstable pelvis and an infected non-union secondary to repeated posterior iliac graft harvest. The orthopaedic surgeon should be aware of this detrimental complication associated with extensive or repeated posterior iliac crest graft harvest.

Differential regulation of EP receptor isoforms during chondrogenesis and chondrocyte maturation.

Regulation of chondrogenesis and chondrocyte maturation by prostaglandins has been a topic of interest during recent years. Particular focus on this area derives from the realization that inhibition of prostaglandin synthesis with non-steroidal anti-inflammatory drugs could impact these cartilage-related processes which are important in skeletal development and are recapitulated during bone healing either post-trauma or post-surgery. In addition to reviewing the relevant literature focused on prostaglandin synthesis and signaling through the G-protein coupled EP receptors, we present novel findings that establish the expression profile of EP receptors in chondroprogenitors and chondrocytes. Further, we begin to examine the signaling that may be involved with the transduction of PGE2 effects in these cells. Our findings suggest that EP2 and EP4 receptor activation of cAMP metabolism may represent a central axis of events that facilitate the impact of PGE2 on the processes of mesenchymal stem cell commitment to chondrogenesis and ultimate chondrocyte maturation.

The interplay of osteogenesis and hematopoiesis: expression of a constitutively active PTH/PTHrP receptor in osteogenic cells perturbs the establishment of hematopoiesis in bone and of skeletal stem cells in the bone marrow.

The ontogeny of bone marrow and its stromal compartment, which is generated from skeletal stem/progenitor cells, was investigated in vivo and ex vivo in mice expressing constitutively active parathyroid hormone/parathyroid hormone-related peptide receptor (PTH/PTHrP; caPPR) under the control of the 2.3-kb bone-specific mouse Col1A1 promoter/enhancer. The transgene promoted increased bone formation within prospective marrow space, but delayed the transition from bone to bone marrow during growth, the formation of marrow cavities, and the appearance of stromal cell types such as marrow adipocytes and cells supporting hematopoiesis. This phenotype resolved spontaneously over time, leading to the establishment of marrow containing a greatly reduced number of clonogenic stromal cells. Proliferative osteoprogenitors, but not multipotent skeletal stem cells (mesenchymal stem cells), capable of generating a complete heterotopic bone organ upon in vivo transplantation were assayable in the bone marrow of caPPR mice. Thus, PTH/PTHrP signaling is a major regulator of the ontogeny of the bone marrow and its stromal tissue, and of the skeletal stem cell compartment.

Primary murine limb bud mesenchymal cells in long-term culture complete chondrocyte differentiation: TGF-beta delays hypertrophy and PGE2 inhibits terminal differentiation.

In vitro models of endochondral bone formation using both primary and immortalized cells have provided insight regarding factors and signaling pathways involved in chondrocyte maturation and endochondral bone formation. However, primary murine cell culture models of chondrocyte differentiation have not been established but have enormous potential due to the possible use of cells from transgenic and knockout animals. Here, we show that stage E11.5 embryonic murine limb bud mesenchymal stem cells in micromass cell culture progress through the stages of chondrogenesis, chondrocyte hypertrophy, terminal differentiation, and matrix calcification. This cell culture system recapitulated the sequential expression of genes that characterize chondrocyte differentiation, including Sox9, col2, colX, MMP13, VEGF, and osteocalcin. TGF-beta treatment for up to 21 days markedly delayed the rate of chondrocyte maturation and inhibited matrix calcification and its related gene expression. In TGF-beta-treated cultures, the hypertrophic and terminal differentiation markers colX, VEGF, MMP13, and osteocalcin were reduced or absent. PGE2 had minimal effects on chondrocyte hypertrophy but delayed terminal differentiation and matrix calcification. Thus, primary murine mesenchymal cells sequentially differentiate through the various stages of chondrocyte maturation and establish a model whereby the role of specific signaling molecules can be examined in cells derived from transgenic or knockout mice.

Ribbing disease: radiographic and biochemical characterization, lack of response to pamidronate.

Ribbing disease is a rare form of sclerosing dysplasia characterized by benign endosteal and periosteal bone growth confined to the diaphyses of the long bones, usually the tibiae and femora. The onset is usually after puberty and the most common presentation is pain that is usually self-limited, but may progress. The etiology and optimal treatment for the disease are unknown. We present the case of a 39-year-old Hispanic man with clinical and radiological manifestations of Ribbing disease. Radiographs and CT imaging demonstrated typical cortical thickening in the mid-diaphyses of the tibiae bilaterally that correlated with intense tracer uptake on (99m)Tc-MDP bone scans. MRI demonstrated cortical thickening and abnormal marrow signal consistent with marrow edema. Bone marrow edema may explain the pain frequently associated with the disease. Multiple serum and urine markers of bone metabolism were within normal limits. In an effort to ameliorate pain, the patient was treated with the bisphosphonate, pamidronate. In spite of treatment, pain increased, requiring additional and larger doses of analgesics. Serial radiographs, CT, bone scans, and MRI all demonstrated disease progression with pamidronate treatment. In this report we present for the first time the finding of bone marrow edema with MRI as well as disease progression during intravenous pamidronate treatment.