Evaluation and Management of a Painful Knee After Total Knee Arthroplasty.

Pain after total knee arthroplasty (TKA) is not infrequent and may be indicative of a broad spectrum of prosthesis-related, intra-articular, or extra-articular pathologies. To diagnose and treat the underlying cause of a painful TKA, systematic evaluation of the patient is critical to ensure that they are managed appropriately and expeditiously. This evidence-based review presents current concepts regarding the pathophysiology, etiology, and diagnosis of painful TKA and our recommended approach for management. [Orthopedics. 2021;44(6):341-352.].

Delirium Reduced With Intravenous Acetaminophen in Geriatric Hip Fracture Patients.

INTRODUCTION: Postoperative delirium is associated with opioid use in the elderly and is a common complication of geriatric hip fractures, with reported incidences from 16% to 70%. Intravenous (IV) acetaminophen is a safe and efficacious medication in elderly patients and has been shown to reduce use of opioids after hip fracture. At our institution, IV acetaminophen was implemented for the first 24 hours postoperatively as part of a multimodal pain control regimen for geriatric hip fracture patients. METHODS: A retrospective review of 123 hip fragility fracture patients older than 60 years from January 2016 to December 2016 was performed. Delirium was identified using a validated chart-based review tool. The rate of delirium, as well as length of stay, pain scores, opioid administration, need for one-to-one supervision, and readmissions were analyzed. RESULTS: Sixty-five patients (52.8%) received IV acetaminophen during this period. No notable differences were found in baseline characteristics between groups. Ten of 65 patients receiving IV acetaminophen postoperatively experienced delirium compared with 19 of 58 who did not receive the medication (15.4% versus 32.8%, P = 0.024). The IV acetaminophen group also required fewer doses of IV opioids on postoperative day 1 (0.37 versus 1.19 doses, P = 0.008), were less likely to require one-to-one supervision (9.2% versus 24.1%, P = 0.025), and had shorter lengths of hospital stay (6.37 versus 8.47 days, P = 0.037). Readmission rates and discharge dispositions did not vary with significance between the two groups. CONCLUSION: The inclusion of IV acetaminophen as part of a multimodal pain regimen led to fewer episodes of delirium in this study. The reduced use of opioids immediately after surgery may have been a large factor in this outcome. Lower delirium rates may reduce the utilization of inpatient resources for direct patient supervision and provide for shorter hospital stays.

Timing of Operative Debridement in Open Fractures.

The optimal treatment of open fractures continues to be an area of debate in the orthopedic literature. Recent research has challenged the dictum that open fractures should be debrided within 6 hours of injury. However, the expedient administration of intravenous antibiotics remains of paramount importance in infection prevention. Multiple factors, including fracture severity, thoroughness of debridement, time to initial treatment, and antibiotic administration, among other variables, contribute to the incidence of infection and complicate identifying an optimal time to debridement.

Direct anterior total hip arthroplasty: Comparative outcomes and contemporary results.

Direct anterior total hip arthroplasty has become increasingly more popular among arthroplasty surgeons, in large part due to the use of an intramuscular interval and desire to reduce soft tissue damage. Several studies have now been published comparing the anterior intramuscular to other commonly used approaches, and many studies have published complication rates on large series of patients. Review of comparative studies indicates direct anterior hips tend towards shorter hospital stays and high rates of patients discharged to home. Although some studies show evidence of early benefit in functional outcomes, there is no strong evidence that the anterior approach provides any long term functional improvements compared to other approaches. Additionally, evidence to support reduced damage to soft tissue may not translate to certain clinical significance. Rates of intra-operative femur fracture, operative time and blood loss rates are notably higher for those developing familiarity with this approach. However, when surgeons have performed a modest number of procedures, the complication rates tend to markedly decrease in most studies to levels comparable to other approaches. Accuracy of component positioning also favors the anterior approach in some studies. This review summarizes the available literature comparing the direct anterior to other approaches for total hip arthroplasty and provides a comprehensive summary of common complications.

Direct anterior total hip arthroplasty: Literature review of variations in surgical technique.

The direct anterior approach to the hip has been suggested to have several advantages compared to previously popular approaches through its use of an intra-muscular and intra-nervous interval between the tensor fasciae latae and sartorius muscles. Recent increased interest in tissue-sparing and minimally-invasive arthroplasty has given rise to a sharp increase in the utilization of direct anterior total hip arthroplasty. A number of variations of the procedure have been described and several authors have published their experiences and feedback to successfully accomplishing this procedure. Additionally, improved understanding of relevant soft tissue constraints and anatomic variants has provided improved margin of safety for patients. The procedure may be performed using specially-designed instruments and a fracture table, however many authors have also described equally efficacious performance using a regular table and standard arthroplasty tools. The capacity to utilize fluoroscopy intra-operatively for component positioning is a valuable asset to the approach and can be of particular benefit for surgeons gaining familiarity. Proper management of patient and limb positioning are vital to reducing risk of intra-operative complications. An understanding of its limitations and challenges are also critical to safe employment. This review summarizes the key features of the direct anterior approach for total hip arthroplasty as an aid to improving the understanding of this important and effective method for modern hip replacement surgeons.

Fractures Due to Gunshot Wounds: Do Retained Bullet Fragments Affect Union?

BACKGROUND: Many types of projectiles, including modern hollow point bullets, fragment into smaller pieces upon impact, particularly when striking bone. This study was performed to examine the effect on time to union with retained bullet material near a fracture site in cases of gunshot injury. METHODS: All gunshot injuries operatively treated with internal fixation at a Level 1 Trauma Center between March 2008 and August 2011 were retrospectively reviewed. Retained bullet load near the fracture site was calculated based on percentage of material retained compared to the cortical diameter of the involved bone. Analyses were performed to assess the effect of the lead-cortical ratio and amount of comminution on time to fracture union. RESULTS: Thirty-two patients (34 fractures) met the inclusion criteria, with an equal number of comminuted (17) and non-comminuted fractures (17). Seventeen of 34 fractures (50%) united within 4 months, 16/34 (47%) developed a delayed union, and 1/34 (3%) developed a nonunion requiring revision surgery. Sixteen of 17 fractures (94%) that united by 4 months had a cumulative amount of bullet fragmentation retained near the fracture site of less than 20% of the cortical diameter. Nine out of 10 fractures (90%) with retained fragments near the fracture site was equal to or exceeding 20% of the cortical diameter had delayed or nonunion. Fracture comminution had no effect on time to union. CONCLUSIONS: The quantity of retained bullet material near the fracture site was more predictive of the rate of fracture union than was comminution. Fractures with bullet fragmentation equal to or exceeding 20% of the cortical width demonstrated a significantly higher rate of delayed union/nonunion compared to those fractures with less retained bullet material, which may indicate a local cytotoxic effect from lead on bone healing. These findings may influence decisions on timing of secondary surgeries. LEVEL OF EVIDENCE: Level III.

Retained bullet removal in civilian pelvis and extremity gunshot injuries: a systematic review.

BACKGROUND: Although gunshot injuries are relatively common, there is little consensus about whether retained bullets or bullet fragments should be removed routinely or only in selected circumstances. QUESTIONS/PURPOSES: We performed a systematic review of the literature to answer the following questions: (1) Is bullet and/or bullet fragment removal from gunshot injuries to the pelvis or extremities routinely indicated? And, if not, (2) what are the selected indications for removal of bullets and/or bullet fragments? METHODS: A search of the English-language literature on the topic of gunshot injury and bullet removal was performed using the National Library of Medicine and MEDLINE(®) and supplemented by hand searching of bibliographies of included references. Studies were included if they provided clinical data on one or both of our study questions; included studies were evaluated using the levels of evidence rubric. Most studies on the subject were expert opinion (Level V evidence), and these were excluded; one Level III study and seven Level IV studies were included. RESULTS: No studies provided a rationale for routine bullet removal in all cases. The studies identified bullet fragment removal as indicated acutely for those located within a joint, the palm, or the sole. Chronic infection, persistent pain at the bullet site, and lead intoxication were reported as late indications for bullet removal. CONCLUSIONS: The evidence base for making clinical recommendations on the topic of bullet and bullet fragment removal after gunshot injury is weak. Level I and II evidence is needed to determine the indications for bullet removal after gunshot injury.

Overexpression of RbfA in the absence of the KsgA checkpoint results in impaired translation initiation.

KsgA, a universally conserved small ribosomal subunit (SSU) rRNA methyltransferase, has recently been shown to facilitate a checkpoint within the ribosome maturation pathway. Under standard growth conditions removal of the KsgA checkpoint has a subtle impact on cell growth; yet, upon overexpresssion of RbfA, a ribosome maturation factor, KsgA becomes essential. Our results demonstrate the requirement of KsgA, in the presence of excess RbfA, both for the incorporation of ribosomal protein S21 to the developing SSU, and for final maturation of SSU rRNA. Also, when SSU biogenesis is perturbed by an imbalance in KsgA and RbfA, a population of 70S-like particles accumulates that is compositionally, functionally and structurally distinct from mature 70S ribosomes. Thus, our work suggests that KsgA and RbfA function together and are required for SSU maturation, and that additional checkpoints likely act to modulate malfunctional 70S particle formation in vivo.

Sensitivity and specificity of noncontrast magnetic resonance imaging reports in the diagnosis of type-II superior labral anterior-posterior lesions in the community setting.

BACKGROUND: Magnetic resonance imaging (MRI) has been suggested to be of high accuracy at academic institutions in the identification of superior labral tears; however, many Type-II superior labral anterior-posterior (SLAP) lesions encountered during arthroscopy have not been previously diagnosed with noncontrast images. This study evaluated the accuracy of diagnosing Type-II SLAP lesions in a community setting with use of noncontrast MRI and analyzed the effect that radiologist training and the scanner type or magnet strength had on sensitivity and specificity. METHODS: One hundred and forty-four patients requiring repair of an arthroscopically confirmed Type-II SLAP lesion who had a noncontrast MRI examination performed within twelve months before the procedure were included in the sensitivity analysis. An additional 100 patients with arthroscopically confirmed, normal superior labral anatomy were identified for specificity analysis. The transcribed interpretations of the images by the radiologists were used to document the diagnosis of a SLAP lesion and were compared with the operative report. The magnet strength, type of MRI system (open or closed), and whether the radiologist had completed a musculoskeletal fellowship were also recorded. RESULTS: Noncontrast MRI identified SLAP lesions in fifty-four of 144 shoulders, yielding an overall sensitivity of 38% (95% confidence interval [CI] = 30%, 46%). Specificity was 94% (95% CI = 87%, 98%), with six SLAP lesions diagnosed in 100 shoulders that did not contain the lesion. Musculoskeletal fellowship-trained radiologists performed with higher sensitivity than those who had not completed the fellowship (46% versus 19%; p = 0.009). CONCLUSIONS: Our results demonstrate a low sensitivity and high specificity in the diagnosis of Type-II SLAP lesions with noncontrast MRI in this community setting. Musculoskeletal fellowship-trained radiologists had significantly higher sensitivities in accurately diagnosing the lesion than did radiologists without such training. Noncontrast MRI is not a reliable diagnostic tool for Type-II SLAP lesions in a community setting.

Deconstructing ribosome construction.

The ribosome is an essential ribonucleoprotein enzyme, and its biogenesis is a fundamental process in all living cells. Recent X-ray crystal structures of the bacterial ribosome and new technologies have allowed a greater interrogation of in vitro ribosome assembly; however, substantially less is known about ribosome biogenesis in vivo. Ongoing investigations are focused on elucidating the cellular processes that facilitate biogenesis of the ribosomal subunits, and many extraribosomal factors, including modification enzymes, remodeling enzymes and GTPases, are being uncovered. Moreover, specific roles for ribosome biogenesis factors in subunit maturation are now being elaborated. Ultimately, such studies will reveal a more complete understanding of processes at work in in vivo ribosome biogenesis.

Mechanistic insight into the ribosome biogenesis functions of the ancient protein KsgA.

While the general blueprint of ribosome biogenesis is evolutionarily conserved, most details have diverged considerably. A striking exception to this divergence is the universally conserved KsgA/Dim1p enzyme family, which modifies two adjacent adenosines in the terminal helix of small subunit ribosomal RNA (rRNA). While localization of KsgA on 30S subunits [small ribosomal subunits (SSUs)] and genetic interaction data have suggested that KsgA acts as a ribosome biogenesis factor, mechanistic details and a rationale for its extreme conservation are still lacking. To begin to address these questions we have characterized the function of Escherichia coli KsgA in vivo using both a ksgA deletion strain and a methyltransferase-deficient form of this protein. Our data reveal cold sensitivity and altered ribosomal profiles are associated with a DeltaksgA genotype in E. coli. Our work also indicates that loss of KsgA alters 16S rRNA processing. These findings allow KsgAs role in SSU biogenesis to be integrated into the network of other identified factors. Moreover, a methyltransferase-inactive form of KsgA, which we show to be deleterious to cell growth, profoundly impairs ribosome biogenesis-prompting discussion of KsgA as a possible antimicrobial drug target. These unexpected data suggest that methylation is a second layer of function for KsgA and that its critical role is as a supervisor of biogenesis of SSUs in vivo. These new findings and this proposed regulatory role offer a mechanistic explanation for the extreme conservation of the KsgA/Dim1p enzyme family.