Abdel, Matthew P

Background: Removal of well-fixed femoral components during revision total hip arthroplasty (THA) can be difficult and time-consuming 1 , leading to numerous complications, such as femoral perforation, bone loss, and fracture. Extended trochanteric osteotomies (ETOs), which provide wide exposure and direct access to the femoral canal under controlled conditions, have become a popular method to circumvent these challenges. ETOs were popularized by Wagner (i.e., the anterior-based osteotomy), and later modified by Paprosky (i.e., the lateral-based osteotomy) 2 . Description: The decision to utilize the laterally based Paprosky ETO versus the anteriorly based Wagner ETO is primarily based on surgeon preference, the location and type of in situ implants, and the osseous anatomy. Typically, a laterally based ETO is most facile in conjunction with a posterior approach and an anteriorly based ETO is most commonly paired with a lateral or anterolateral approach. Attention must be paid to maintaining vascularity to the osteotomy fragment, including minimizing stripping of the vastus lateralis from the osteotomy fragment and maintaining abductor attachments to the osteotomy fragment. When utilizing a laterally based ETO, the posterior border of the vastus lateralis must be carefully elevated to provide exposure for performance of the osteotomy. When an anteriorly based osteotomy is performed, the surgeon may instead extend the abductor tenotomy proximally with use of a longitudinal split of the vastus lateralis distally, which helps to keep the anterior and posterior sleeves of soft tissue in continuity. In either approach, dissection of the vastus lateralis involves managing several large vascular perforators. We prefer performing careful blunt dissection to identify the perforators and prophylactically controlling them, with ligation of large vessels and electrocautery of smaller vessels. Vascular clips are also available in case difficult-to-control bleeding is encountered. In general, an oscillating saw (with preference for a thin blade) is utilized to complete the posterior longitudinal limb of the ETO, extending approximately 12 to 16 cm distally from the tip of the greater trochanter. Although a 12 to 16-cm zone is required to maintain maximum vascularity to the osteotomized fragment, the osteotomy length must ultimately be determined by (1) the length of the femoral component to be removed; (2) the presence of distal bone ingrowth, ongrowth, or cement; and (3) the presence of distal hardware or stemmed knee components. A smaller oscillating saw is then utilized to complete the transverse limb at the previously identified distal extent. A high-speed pencil-tip burr is utilized to complete the corners of the osteotomy in a rounded configuration, and a combination of saws and pencil-tip burrs is utilized to create partial proximal and distal anterior longitudinal limbs of the osteotomy to the extent allowed by the soft-tissue attachments. The anterior longitudinal limb may be further weakened in a controlled fashion with use of serial drill holes. The anterior longitudinal limb then undergoes controlled fracture by placement of 2 to 4 broad straight osteotomes in the posterior longitudinal limb. These osteotomes are carefully levered anteriorly in unison with a gentle, steady force. After the ETO is completed, intramedullary prostheses, hardware, and cement are removed; the acetabulum is addressed as needed; and a final femoral stem is implanted, if appropriate. After completion of the osteotomy, the osteotomized fragment must be retracted gently, with care taken to avoid a fracture and maintain vascularity. To this end, debridement of the endosteum of the osteotomized fragment, including any cement removal, should be avoided until the end of the procedure, when the osteotomy is ready to be closed. Our preferred method for closure is to place 1 prophylactic cable 1 cm distal to the osteotomy, 1 to 2 cables along the diaphyseal segment of the osteotomy, and 1 Luque wire above the less trochanter. A Luque wire is our specific choice for the location above the lesser trochanter because it sits in the effective joint space; however, the use of Luque wires distal to the lesser trochanter is also acceptable. A strut allograft or locking plate can be utilized to reinforce the osteotomy in rare cases or to bridge interprosthetic stress risers. Trochanteric implants are typically avoided because of the low rate of clinically relevant trochanteric migration with this closure technique and because of the high rate of symptomatic implants with trochanteric claws or plates. Alternatives: An alternative osteotomy of similar exposure is the transfemoral osteotomy. Additionally, a variety of non-extended trochanteric osteotomies, such as trochanteric slide osteotomies, offer more limited exposure. Rationale: Femoral surgical exposure for revision THA can be aided by performing transfemoral osteotomies, but these provide less precise control of the separate proximal femoral osteotomized segment(s), and healing and fixation can be less reliable. Less invasive osteotomies such as non-extended trochanteric osteotomies typically do not provide adequate exposure in challenging cases for which ETO is being considered. Expected Outcomes: ETOs have high union rates, and notable trochanteric migration is infrequent. The most common complications are fracture of the osteotomy fragment intraoperatively or postoperatively. Radiographic and clinical union is achieved in 98% of patients. The mean proximal trochanteric osteotomy fragment migration prior to union is 3 mm. ETO fragment migration of >1 cm occurs in just 7% of hips. Postoperative greater trochanter fractures occur in 9% of hips. The 10-year survivorship free of revision for aseptic femoral loosening, free of femoral or acetabular component removal or revision for any reason, and free of reoperation for any reason is 97%, 91%, and 82%, respectively 3 . Important Tips: Attention should be paid to patient anatomy, deformity, surgical approach, and implant type when choosing to perform a laterally based Paprosky or anteriorly based Wagner ETO. Appropriate length of the posterior longitudinal limb of the ETO is approximately 12 to 16 cm distally from the tip of the greater trochanter. Attention must be paid to maintaining vascularity to the osteotomy fragment, including minimizing stripping of the vastus lateralis from the osteotomy fragment and maintaining abductor attachments to the osteotomy fragment. A high-speed pencil-tip burr should be utilized to complete the corners of the osteotomy in a rounded configuration in order to avoid stress risers. The anterior longitudinal limb is completed by controlled fracture of the remaining intervening segment in order to maintain vastus lateralis attachments and vascular supply to the osteotomy fragment. The ETO is closed with use of cerclage cables and/or double-stranded Luque wires, typically utilizing a total of 3 to 4 in order to obtain secure fixation without compromising local biology. Acronyms and Abbreviations: MFT = modular fluted tapered

Background: Dual-mobility (DM) implants reduce the risk of dislocation in patients who have undergone total hip arthroplasty (THA); however, DM implants are at risk for large-head dislocation and intraprosthetic dissociation (IPD), where the inner femoral head dissociates from the outer polyethylene head. This study aimed to report the incidence of DM dislocation and IPD, evaluate the rate of recognition of IPD before and after reduction, investigate the outcomes of these complications, and provide treatment recommendations for their management. Methods: Between 2010 and 2021, 695 primary and 758 revision THAs were performed with DM constructs at a single institution. There were 44 large-head dislocations (3.0%) and 10 IPDs (0.7%). Four additional IPDs occurred during attempted closed reduction, increasing the IPD incidence to 0.96%. We reviewed prior instability history, dislocation management, success of reduction, recognition of IPD, and subsequent rates of revision and complications. The mean follow-up was 2.5 years. Results: Nine of 10 IPDs were missed at presentation and thus not treated as such. Sixty-three percent of attempted closed reductions in the emergency department failed and led to 4 IPDs and 1 periprosthetic fracture. Reduction success was associated with the following factors: use of general anesthesia with paralysis (p = 0.02), having the reduction performed by an orthopaedist (p = 0.03), and undergoing only 1 reduction attempt (p = 0.015). Two-thirds of dislocations required revision. The rate of redislocation was 33%, and 5 hips required subsequent revision at a mean of 1.8 years after the initial dislocation. Conclusions: We present an evaluation of DM-implant dislocation and dissociation along with management recommendations based on these data. Given the low success and high complication rates of attempted closed reduction and the need for eventual revision, we recommend that all patients with dislocated DM implants be brought to the operating room for closed reduction as well as potential revision if the reduction fails. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

AimsContemporary outcomes of primary total hip arthroplasties (THAs) with highly cross-linked polyethylene (HXLPE) liners in patients with inflammatory arthritis have not been well studied. This study examined the implant survivorship, complications, radiological results, and clinical outcomes of THA in patients with inflammatory arthritis.MethodsWe identified 418 hips (350 patients) with a primary diagnosis of inflammatory arthritis who underwent primary THA with HXLPE liners from January 2000 to December 2017. Of these hips, 68% had rheumatoid arthritis (n = 286), 13% ankylosing spondylitis (n = 53), 7% juvenile rheumatoid arthritis (n = 29), 6% psoriatic arthritis (n = 24), 5% systemic lupus erythematosus (n = 23), and 1% scleroderma (n = 3). Mean age was 58 years (SD 14.8), 66.3% were female (n = 277), and mean BMI was 29 kg/m2 (SD 7). Uncemented femoral components were used in 77% of cases (n = 320). Uncemented acetabular components were used in all patients. Competing risk analysis was used accounting for death. Mean follow-up was 4.5 years (2 to 18).ResultsThe ten-year cumulative incidence of any revision was 3%, and was highest in psoriatic arthritis patients (16%). The most common indications for the 15 revisions were dislocations (n = 8) and periprosthetic joint infections (PJI; n = 4, all on disease-modifying antirheumatic drugs (DMARDs)). The ten-year cumulative incidence of reoperation was 6.1%, with the most common indications being wound infections (six cases, four on DMARDs) and postoperative periprosthetic femur fractures (two cases, both uncemented femoral components). The ten-year cumulative incidence of complications not requiring reoperation was 13.1%, with the most common being intraoperative periprosthetic femur fracture (15 cases, 14 uncemented femoral components; p = 0.13). Radiological evidence of early femoral component subsidence was observed in six cases (all uncemented). Only one femoral component ultimately developed aseptic loosening. Harris Hip Scores substantially improved (p < 0.001).ConclusionContemporary primary THAs with HXLPE in patients with inflammatory arthritis had excellent survivorship and good functional outcomes regardless of fixation method. Dislocation, PJI, and periprosthetic fracture were the most common complications in this cohort with inflammatory arthritis.Cite this article: Bone Joint J 2023;105-B(7):768–774.

AimsKnowledge on total knee arthroplasties (TKAs) in patients with a history of poliomyelitis is limited. This study compared implant survivorship and clinical outcomes among affected and unaffected limbs in patients with sequelae of poliomyelitis undergoing TKAs.MethodsA retrospective review of our total joint registry identified 94 patients with post-polio syndrome undergoing 116 primary TKAs between January 2000 and December 2019. The mean age was 70 years (33 to 86) with 56% males (n = 65) and a mean BMI of 31 kg/m2 (18 to 49). Rotating hinge TKAs were used in 14 of 63 affected limbs (22%), but not in any of the 53 unaffected limbs. Kaplan-Meier survivorship analyses were completed. The mean follow-up was eight years (2 to 19).ResultsThe ten-year survivorship free from revision was 91% (95% confidence interval (CI) 81 to 100) in affected and 84% (95% CI 68 to 100) in unaffected limbs. There were six revisions in affected limbs: three for periprosthetic femoral fractures and one each for periprosthetic joint infection (PJI), patellar clunk syndrome, and instability. Unaffected limbs were revised in four cases: two for instability and one each for PJI and tibial component loosening. The ten-year survivorship free from any reoperation was 86% (95% CI 75 to 97) and 80% (95% CI 64 to 99) in affected and unaffected limbs, respectively. There were three additional reoperations among affected and two in unaffected limbs. There were 12 nonoperative complications, including four periprosthetic fractures. Arthrofibrosis occurred in five affected (8%) and two unaffected limbs (4%). Postoperative range of motion decreased with 31% achieving less than 90° knee flexion by five years.ConclusionTKAs in post-polio patients are complex cases associated with instability, and one in four require constraint on the affected side. Periprosthetic fracture was the main mode of failure. Arthrofibrosis rates were high and twice as frequent in affected limbs.Cite this article: Bone Joint J 2023;105-B(6):635–640.

Aims The aim of this study was to determine the prevalence of depressive and anxiety disorders prior to total hip (THA) and total knee arthroplasty (TKA) and to assess their impact on the rates of any infection, revision, or reoperation. Methods Between January 2000 and March 2019, 21,469 primary and revision arthroplasties (10,011 THAs; 11,458 TKAs), which were undertaken in 15,504 patients at a single academic medical centre, were identified from a 27-county linked electronic medical record (EMR) system. Depressive and anxiety disorders were identified by diagnoses in the EMR or by using a natural language processing program with subsequent validation from review of the medical records. Patients with mental health diagnoses other than anxiety or depression were excluded. Results Depressive and/or anxiety disorders were common before THA and TKA, with a prevalence of 30% in those who underwent primary THA, 33% in those who underwent revision THA, 32% in those who underwent primary TKA, and 35% in those who underwent revision TKA. The presence of depressive or anxiety disorders was associated with a significantly increased risk of any infection (primary THA, hazard ratio (HR) 1.5; revision THA, HR 1.9; primary TKA, HR 1.6; revision TKA, HR 1.8), revision (THA, HR 1.7; TKA, HR 1.6), re-revision (THA, HR 2.0; TKA, HR 1.6), and reoperation (primary THA, HR 1.6; revision THA, HR 2.2; primary TKA, HR 1.4; revision TKA, HR 1.9; p < 0.03 for all). Patients with preoperative depressive and/or anxiety disorders were significantly less likely to report “much better” joint function after primary THA (78% vs 87%) and primary TKA (86% vs 90%) compared with those without these disorders at two years postoperatively (p < 0.001 for all). Conclusion The presence of depressive or anxiety disorders prior to primary or revision THA and TKA is common, and associated with a significantly higher risk of infection, revision, reoperation, and dissatisfaction. This topic deserves further study, and surgeons may consider mental health optimization to be of similar importance to preoperative variables such as diabetic control, prior to arthroplasty. Cite this article: Bone Joint J 2023;105-B(5):526–533.

AbstractPurposeThis pilot study aimed to use proteomic profiling of sonicate fluid samples to compare host response during Staphylococcus aureus‐associated periprosthetic joint infection (PJI) and non‐infected arthroplasty failure (NIAF) and identify potential novel biomarkers differentiating the two.Experimental designIn this pilot study, eight sonicate fluid samples (four from NIAF and four from S. aureus PJI) were studied. Samples were reduced, alkylated, and trypsinized overnight, followed by analysis using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) on a high‐resolution Orbitrap Eclipse mass spectrometer. MaxQuant software suite was used for protein identification, filtering, and label‐free quantitation.ResultsPrincipal component analysis of the identified proteins clearly separated S. aureus PJI and NIAF samples. Overall, 810 proteins were identified based on their detection in at least three out of four samples from each group; 35 statistically significant differentially abundant proteins (DAPs) were found (two‐sample t‐test p‐values ≤0.05 and log2fold‐change values ≥2 or ≤−2). Gene ontology pathway analysis found that microbial defense responses, specifically those related to neutrophil activation, to be increased in S. aureus PJI compared to NIAF samples.Conclusion and clinical relevanceProteomic profiling of sonicate fluid using LC‐MS/MS differentiated S. aureus PJI and NIAF in this pilot study. Further work is needed using a larger sample size and including non‐S. aureus PJI and a diversty of NIAF‐types.

AbstractArthrofibrosis, which is characterized by excessive scar tissue and limited motion, can complicate the daily functioning of patients after total knee arthroplasty (TKA). Molecular hallmarks of arthrofibrosis include pathologic accumulation of myofibroblasts and disproportionate collagen deposition. Epigenetic mechanisms, including posttranslation modification of histones, control gene expression and may regulate fibrotic events. This study assessed the role of the bromodomain and extra‐terminal (BET) proteins on myofibroblast differentiation. This group of epigenetic regulators recognize acetylated lysines and are targeted by a class of drugs known as BET inhibitors. RNA‐seq analysis revealed robust mRNA expression of three BET members (BRD2, BRD3, and BRD4) while the fourth member (BRDT) is not expressed in primary TKA knee outgrowth fibroblasts. RT‐qPCR and western blot analyses revealed that BET inhibition with the small molecule JQ1 impairs TGFβ1‐induced expression of ACTA2, a key myofibroblast marker, in primary outgrowth knee fibroblasts. Similarly, JQ1 administration also reduced COL3A1 mRNA levels and collagen deposition as monitored by picrosirius red staining. Interestingly, the inhibitory effects of JQ1 on ACTA2 mRNA and protein expression, as well as COL3A1 expression and collagen deposition, were paralleled by siRNA‐mediated depletion of BRD4. Together, these data reveal that BRD4‐mediated epigenetic events support TGFβ1‐mediated myofibroblast differentiation and collagen deposition as seen in arthrofibrosis. To our knowledge, these are the first studies that assess epigenetic regulators and their downstream events in the context of arthrofibrosis. Future studies may reveal clinical utility for drugs that target epigenetic pathways, specifically BET proteins, in the prevention and treatment of arthrofibrosis.

Background: Although cellularity is traditionally assessed morphologically, deep sequencing approaches being used for microorganism detection may be able to provide information about cellularity. We hypothesized that cellularity predicted using CIBERSORTx (Stanford University), a transcriptomic-based cellular deconvolution tool, would differentiate between infectious and non-infectious arthroplasty failure. Methods: CIBERSORTx-derived cellularity profiles of 93 sonicate fluid samples, including 53 from subjects who underwent failed arthroplasties due to periprosthetic joint infection (PJI) (abbreviated for the purpose of this study as PJIF) and 40 from subjects who had undergone non-infectious arthroplasty failure (abbreviated NIAF) that had been subjected to bulk RNA sequencing were evaluated. Results: Samples from PJIF and NIAF subjects were differentially clustered by principal component analysis based on the cellularity profile. Twelve of the 22 individual predicted cellular fractions were differentially expressed in the PJIF cases compared with the NIAF cases, including increased predicted neutrophils (mean and standard error, 9.73% ± 1.06% and 0.81% ± 0.60%), activated mast cells (17.12% ± 1.51% and 4.11% ± 0.44%), and eosinophils (1.96% ± 0.37% and 0.42% ± 0.21%), and decreased predicted M0 macrophages (21.33% ± 1.51% and 39.75% ± 2.45%), M2 macrophages (3.56% ± 0.52% and 8.70% ± 1.08%), and regulatory T cells (1.57% ± 0.23% and 3.20% ± 0.34%). The predicted total granulocyte fraction was elevated in the PJIF cases (32.97% ± 2.13% and 11.76% ± 1.61%), and the samples from the NIAF cases had elevated predicted total macrophage and monocyte (34.71% ± 1.71% and 55.34% ± 2.37%) and total B cell fractions (5.89% ± 0.30% and 8.62% ± 0.86%). Receiver operating characteristic curve analysis identified predicted total granulocytes, neutrophils, and activated mast cells as highly able to differentiate between the PJIF cases and the NIAF cases. Within the PJIF cases, the total granulocyte, total macrophage and monocyte, M0 macrophage, and M2 macrophage fractions were differentially expressed in Staphylococcus aureus compared with Staphylococcus epidermidis -associated samples. Within the NIAF cases, the predicted total B cell, naïve B cell, plasma cell, and M2 macrophage fractions were differentially expressed among different causes of failure. Conclusions: CIBERSORTx can predict the cellularity of sonicate fluid using transcriptomic data, allowing for the evaluation of the underlying immune response during the PJIF and NIAF cases, without a need to phenotypically assess cell composition.

Aims We have previously reported the mid-term outcomes of revision total knee arthroplasty (TKA) for flexion instability. At a mean of four years, there were no re-revisions for instability. The aim of this study was to report the implant survivorship and clinical and radiological outcomes of the same cohort of of patients at a mean follow-up of ten years. Methods The original publication included 60 revision TKAs in 60 patients which were undertaken between 2000 and 2010. The mean age of the patients at the time of revision TKA was 65 years, and 33 (55%) were female. Since that time, 21 patients died, leaving 39 patients (65%) available for analysis. The cumulative incidence of any re-revision with death as a competing risk was calculated. Knee Society Scores (KSSs) were also recorded, and updated radiographs were reviewed. Results The cumulative incidence of any re-revision was 13% at a mean of ten years. At the most recent-follow-up, eight TKAs had been re-revised: three for recurrent flexion instability (two fully revised to varus-valgus constrained implants (VVCs), and one posterior-stabilized (PS) implant converted to VVC, one for global instability (PS to VVC), two for aseptic loosening of the femoral component, and two for periprosthetic joint infection). The ten-year cumulative incidence of any re-revision for instability was 7%. The median KSS improved significantly from 45 (interquartile range (IQR) 40 to 50) preoperatively to 70 (IQR 45 to 80) at a mean follow-up of ten years (p = 0.031). Radiologically, two patients, who had not undergone revision, had evidence of loosening (one tibial and one patellar). The remaining components were well fixed. Conclusion We found fair functional outcomes and implant survivorship at a mean of ten years after revision TKA for flexion instability with a PS implant. Recurrent instability and aseptic loosening were the most common indications for re-revision. Components with increased constraint, such as a VVC or hinged, should be used in these patients in order to reduce the risk of recurrent instability. Cite this article: Bone Joint J 2022;104-B(10):1126–1131.

Abstract Background The optimal duration of antibiotic therapy after debridement and implant retention (DAIR) for periprosthetic joint infections (PJIs) is debated. Furthermore, the best antibiotic regimens for staphylococcal PJI are also unclear. In this study, we evaluated the impact of antibiotic therapy duration on the risk of failure. We assessed the utility of rifampin-based regimens for staphylococcal PJI managed with DAIR. Methods We performed a retrospective cohort study of patients 18 years and older diagnosed with hip and knee PJI who underwent DAIR between January 1, 2008 and 31 December 31, 2018 at Mayo Clinic, USA. The outcome was failure of DAIR. For statistical analysis, joint-stratified Cox regression models adjusted for age, sinus tract, symptom duration, and primary/revision arthroplasty were performed. Results We examined 247 cases of PJI with a median follow-up of 4.4 years (interquartile range [IQR], 2.3–7) after DAIR. The estimated 5-year cumulative incidence of failure was 28.1% (n = 65). There was no association between the duration of intravenous (IV) antibiotics (median 42 days; IQR, 38–42) and treatment failure (P = .119). A shorter duration of subsequent oral antibiotic therapy was associated with a higher risk of failure (P = .005; eg, 90-day vs 1-year duration; hazard ratio [HR], 3.50; 95% confidence interval [CI], 1.48–8.25). For staphylococcal knee PJI, both the use and longer duration of a rifampin-based regimen were associated with a lower risk of failure (both P = .025). There was no significant association between fluoroquinolone (FQ) use and failure (HR, 0.62; 95% CI, .31–1.24; P = .172). Conclusions The duration of initial IV antibiotic therapy did not correlate with treatment failure in this cohort of patients. Rifampin use is recommended for staphylococcal knee PJI. There was no apparent benefit of FQ use in staphylococcal PJI.