The relative advantages and disadvantages of two-stage versus one-stage management of infected total hip arthroplasties are the current subject of intense debate. To understand the merits of each approach detailed information on the short and, importantly, longer-term outcomes of each must be known. The purpose of this study was to assess the long-term results of two-stage exchange arthroplasty for THAs in one of the largest series to date. We identified 331 infected THAs treated with a two-stage exchange arthroplasty between 1993 and 2021 at a single institution. Patients were excluded if they had prior treatment for infection. Mean age at reimplantation was 66 years, 38% were female, and mean BMI was 30 kg/m2. PJI diagnosis was based on the 2011 MSIS criteria. A competing risk model accounting for death was utilized. Mean follow up was 8 years. The cumulative incidence of reinfection was 7% at 1 year and 11% at 5 and 10 years. Factors predictive of reinfection included BMI>30 kg/m2 (HR 2; p=0.049), and need for a spacer exchange (HR 3.2; p=0.006). The cumulative incidence of any revision was 13% at 5 and 10 years. The cumulative incidence of aseptic revision was 3% at 1 year, 7% at 5 years, and 8% at 10 years. Dislocation occurred in 33 hips (11% at 10 years; 45% required revision). Factors predictive of dislocation were female sex (HR 2; p=0.047) and BMI<30 kg/m2 (HR 3; p=0.02). The mean HHS improved from 54 to 75 at 10 years. In this series of 331 two-stage exchange arthroplasties performed for infected hips, we found a low aseptic revision rate (8%) and a low rate of reinfection (11%) at 10 years. These long-term mechanical and infection data must be kept in mind when considering a paradigm shift to one-stage exchanges. Level of Evidence: Level III
Angular proximal femoral deformities increase the technical complexity of primary total hip arthroplasties (THAs). The goals were to determine the long-term implant survivorship, risk factors, complications, and clinical outcomes of contemporary primary THAs in this difficult cohort. Our institutional total joint registry was used to identify 119 primary THAs performed in 109 patients with an angular proximal femoral deformity between 1997 and 2017. The deformity was related to previous femoral osteotomy in 85%, and developmental or metabolic disorders in 15%. 53% had a predominantly varus angular deformity. The mean age was 44 years, mean BMI was 29 kg/m2, and 59% were female. An uncemented metaphyseal fixation stem was used in 30%, an uncemented diaphyseal fixation stem in 28%, an uncemented modular body stem with metaphyseal fixation sleeve in 24%, and a cemented stem in 18%. Simultaneous corrective femoral osteotomy was performed in 18%. Kaplan-Meier survivorships and Harris hip scores were reported. Mean follow-up was 8 years. The 10-year survivorships free of femoral loosening, aseptic femoral revision, any revision, and any reoperation were 95%, 93%, 90% and 88%, respectively. Revisions occurred in 13 hips for: aseptic femoral component loosening (3), stem fracture (2), dislocation (2), aseptic acetabular loosening (2), polyethylene liner exchange (2), and infection (2). Preoperative varus angular deformities were associated with a higher risk of any revision (HR 10, p=0.03), and simultaneous osteotomies with a higher risk of any reoperation (HR 3.6, p=0.02). Mean Harris hip scores improved from 52 preoperatively to 82 at 10 years (p<0.001). In the largest series to date of primary THAs in patients with angular proximal femoral deformities, we found a good 10-year survivorship free from any revision. Varus angular deformities, particularly those treated with a simultaneous osteotomy due to the magnitude or location of the deformity, had a higher reoperation rate. Keywords: Proximal femoral deformity; dysplasia; femoral osteotomy; survivorship; revision Level of evidence: Level III, comparative retrospective cohort
Cup-cage constructs are one of several methods commonly used to treat severe acetabular bone loss during contemporary revision total hip arthroplasty. The purpose of this study was to provide a long-term results of the technique with emphasis on implant survivorship, radiographic results, and clinical outcomes for both full and half cup-cage reconstructions. We identified 57 patients treated with a cup-cage reconstruction for major acetabular bone loss between 2002–2012. All patients had Paprosky Type 2B through 3B bone loss, with 60% having an associated pelvic discontinuity. Thirty-one patients received a full cup-cage construct, and 26 a half cup-cage. Mean age at reconstruction was 66 years, 75% were female, and the mean BMI was 27 kg/m2. Mean follow-up was 10 years. The 10-year cumulative incidences of any revision were 14% and 12% for the full and half cup-cage construct groups, respectively. Of the 9 revisions, 3 were for dislocation, 2 for aseptic loosening and construct failure (both were pelvic discontinuities), 1 for adverse local tissue reaction, and 1 for infection with persistent pelvic discontinuity. The 10-year cumulative incidences of revision for aseptic loosening were 4.5% and 5% for the full and half cup-cage constructs, respectively. Of the unrevised cases, incomplete and non-progressive zone 3 radiolucent lines were observed in 10% of patients in each group. Three patients experienced partial motor and sensory sciatic nerve palsies (2 in the full and 1 in the half cup-cage group). Both the full and half cup-cage cohorts demonstrated significantly improved Harris hip scores. Full and half cup-cage reconstructions for major acetabular defects were successful at 10 years in regards to acetabular fixation without appreciable differences between the two techniques. However, zone 3 radiolucent lines were not uncommon in association with discontinuities, and dislocation continues to be a problem.
There is a paucity of long-term data on modular fluted tapered (MFT) stems for two-stage reimplantation following periprosthetic joint infection (PJI). The purpose of this study was to evaluate implant survivorship, radiographic results, and clinical outcomes in a large cohort of reimplantation THAs using MFT stems. We identified 236 reimplantation THAs from a single tertiary care academic institution from 2000 to 2020. Two designs of MFT stems were used as part of an established two-stage exchange protocol for the treatment of PJI. Mean age at reimplantation was 65 years, mean BMI was 32 kg/m2, and 46% were female. Median stem diameter was 19 mm, and median stem length was 195 mm. Mean follow-up was 7 years. A competing risk model accounting for death was utilized. The 15-year cumulative incidence of any revision was 24%. There were 48 revisions, with the most common reasons being dislocation (n=25) and PJI (n=16). The 15-year cumulative incidence of any reoperation was 28%. Only 13 revisions involved the fluted tapered portion of the component (FTC), for a 15-year cumulative incidence of any FTC revision of 8%. Only 2 FTCs were revised for aseptic loosening, resulting in a 15-year cumulative incidence of FTC revision for aseptic loosening of 1%. Stem subsidence >5 mm occurred in 2% of unrevised cases, and all stems were radiographically stable at most recent follow-up. Mean HHS was 77 at most recent follow-up. This series demonstrated that MFT stems were durable and reliable even in the setting of two-stage reimplantation for infection. While the incidence of aseptic loosening was very low, the incidence of any revision was 24% at 15 years, primarily caused by dislocation and recurrent PJI. Level of Evidence: IV
The last two decades have seen remarkable technological advances in total hip arthroplasty (THA) implant design. Porous ingrowth surfaces and highly crosslinked polyethylene (HXLPE) have been expected to dramatically improve implant survivorship. The purpose of the present study was to evaluate survival of contemporary cementless acetabular components following primary THA. 16,421 primary THAs performed for osteoarthritis between 2000 and 2019 were identified from our institutional total joint registry. Patients received one of 12 contemporary cementless acetabular designs with HXLPE liners. Components were grouped based on ingrowth surface into 4 categories: porous titanium (n=10,952, mean follow-up 5 years), porous tantalum (n=1223, mean follow-up 5 years), metal mesh (n=2680, mean follow-up 6.5 years), and hydroxyapatite (HA) coated (n=1566, mean follow-up 2.4 years). Kaplan-Meier analyses were performed to assess the survivorship free of acetabular revision. A historical series of 182 Harris-Galante-1 (HG-1) acetabular components was used as reference. The 15-year survivorship free of acetabular revision was >97% for all 4 contemporary cohorts. Compared to historical control, porous titanium (HR 0.06, 95% CI 0.02–0.17, p<0.001), porous tantalum (HR 0.09, 95%CI 0.03–0.29, p<0.001), metal mesh (HR 0.11, 95%CI 0.04–0.31, p<0.001), and HA-coated (HR 0.14, 95%CI 0.04–0.48, p=0.002) ingrowth surfaces had significantly lower risk of any acetabular revision. There were 16 cases (0.1%) of acetabular aseptic loosening that occurred in 8 (0.07%) porous titanium, 5 (0.2%) metal mesh, and 3 (0.2%) HA-coated acetabular components. 7 of the 8 porous titanium aseptic loosening cases occurred in one known problematic design. There were no cases of aseptic loosening in the porous tantalum group. Modern acetabular ingrowth surfaces and HXLPE liners have improved on historical results at the mid-term. Contemporary designs have extraordinarily high revision-free survivorship, and aseptic loosening is now a rare complication. At mid-term follow-up, survivorship of contemporary uncemented acetabular components is excellent and aseptic loosening occurs in a very small minority of patients.
As has been shown in larger animal models, knee immobilization can lead to arthrofibrotic phenotypes. Our study included 168 C57BL/6J female mice, with 24 serving as controls, and 144 undergoing a knee procedure to induce a contracture without osteoarthritis (OA). Experimental knees were immobilized for either four weeks (72 mice) or eight weeks (72 mice), followed by a remobilization period of zero weeks (24 mice), two weeks (24 mice), or four weeks (24 mice) after suture removal. Half of the experimental knees also received an intra-articular injury. Biomechanical data were collected to measure passive extension angle (PEA). Histological data measuring area and thickness of posterior and anterior knee capsules were collected from knee sections.Aims
Methods
Outcomes of current operative treatments for arthrofibrosis after total knee arthroplasty (TKA) are not consistently positive or predictable. Pharmacological in vivo studies have focused mostly on prevention of arthrofibrosis. This study used a rabbit model to evaluate intra-articular (IA) effects of celecoxib in treating contracted knees alone, or in combination with capsular release. A total of 24 rabbits underwent contracture-forming surgery with knee immobilization followed by remobilization surgery at eight weeks. At remobilization, one cohort underwent capsular release (n = 12), while the other cohort did not (n = 12). Both groups were divided into two subcohorts (n = 6 each) – one receiving IA injections of celecoxib, and the other receiving injections of vehicle solution (injections every day for two weeks after remobilization). Passive extension angle (PEA) was assessed in live rabbits at 10, 16, and 24 weeks, and disarticulated limbs were analyzed for capsular stiffness at 24 weeks.Aims
Methods
Diagnosing acute postoperative periprosthetic joint infections (PJIs) after primary total knee arthroplasties (TKAs) remains difficult. Published diagnostic thresholds for ESR, CRP, and synovial fluid analysis have not been replicated. We aimed to validate the optimal cutoffs for detecting acute postoperative PJIs in a large series of primary TKAs. We retrospectively identified 27,066 primary TKAs performed between 2000–2019. Within 12 weeks, 171 knees (170 patients) had a synovial fluid aspiration. Patients were divided into two groups: evaluation <6 weeks or 6–12 weeks. The 2011 MSIS criteria for PJI diagnosed infection in 22 knees. Mann-Whitney U tests compared medians; ROC analyses determined optimal thresholds. Mean follow-up was 5 years.Introduction
Methods
Patients undergoing primary total hip arthroplasty (THA) following pelvic radiation have historically had poor survivorship free of aseptic acetabular component loosening. However, several series have reported improved results with tantalum acetabular components. The purpose of this study was to assess implant survivorship, radiographic results, and clinical outcomes of contemporary, non-tantalum, porous acetabular components in the setting of prior pelvic radiation. We retrospectively reviewed 33 patients (38 hips) with prior therapeutic pelvic radiation between 2006 and 2016 who underwent primary THA. The mean overall pelvic radiation dose was 6300 cGy with a mean latency period to THA of 5 years. The most common acetabular component was Pinnacle (Depuy-Synthes) in 76%, followed by Trident (Stryker) in 8%, Tritanium (Stryker) in 8%, Trilogy (Zimmer-Biomet) in 5%, and G7 (Zimmer-Biomet) in 3%. Eighty-seven percent of cups were fixed with screws, of which the mean number used was 3. The mean age at primary THA was 74 years, 76% were male, and the mean BMI was 30 kg/m2. Mean follow-up was 5 years.Introduction
Methods
Arthrofibrosis remains a persistent complication following total knee arthroplasty (TKA). Although manipulation under anesthesia (MUA) is an effective early treatment, the risks and value of this procedure beyond 3 months after TKA remain controversial. The purpose of this study was to examine the safety and efficacy of late MUAs for arthrofibrosis. From our institutional total joint registry, 82 TKAs (77 patients) who underwent MUA >3 months after primary (83%) or revision (17%) TKA were identified. Mean time to MUA was 7 months: 66% performed between 4–6 months, 18% between 7–12 months, 16% beyond 12 months. MUAs were coupled with arthroscopic assistance in 26% (12% limited lysis of adhesions, 13% formal arthroscopic debridement). Mean age was 61 years, 59% females, and mean BMI was 33kg/m2. Mean follow-up was 5 years.Introduction
Methods
Septic arthritis of the native knee often results in irreversible joint damage leading to the need for a total knee arthroplasty (TKA). This study examines the mid-term risk of periprosthetic joint infection (PJI), aseptic revision, any revision, and any reoperation in primary TKAs after septic arthritis of the native knee compared to a control cohort of primary TKAs performed for osteoarthritis (OA). We retrospectively identified 215 primary TKAs performed between 1971 and 2016 at a single institution following septic arthritis of the native knee. Eighty-two percent (177 cases) were treated in a single setting, whereas a two-stage exchange arthroplasty protocol was utilized in 18% (39 cases) for ongoing or suspected active native knee septic arthritis. Each case was matched 1:1 based on age, sex, body mass index (BMI), and surgical year to a primary TKA for OA. Mean age and BMI were 63 years and 30 kg/m2, respectively. Mean follow-up was 9 years.Introduction
Methods
Instability remains a common complication following total hip arthroplasty (THA) and continues to account for the highest percentage of revisions in numerous registries. Many risk factors have been described, yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to apply a machine learning algorithm to develop a patient-specific risk score capable of dynamic adjustment based on operative decisions. 22,086 THA performed between 1998–2018 were evaluated. 632 THA sustained a postoperative dislocation (2.9%). Patients were robustly characterized based on non-modifiable factors: demographics, THA indication, spinal disease, spine surgery, neurologic disease, connective tissue disease; and modifiable operative decisions: surgical approach, femoral head size, acetabular liner (standard/elevated/constrained/dual-mobility). Models were built with a binary outcome (event/no event) at 1-year and 5-year postoperatively. Inverse Probability Censoring Weighting accounted for censoring bias. An ensemble algorithm was created that included Generalized Linear Model, Generalized Additive Model, Lasso Penalized Regression, Kernel-Based Support Vector Machines, Random Forest and Optimized Gradient Boosting Machine. Convex combination of weights minimized the negative binomial log-likelihood loss function. Ten-fold cross-validation accounted for the rarity of dislocation events.Introduction
Methods
The prevalence of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is rising in concert with life expectancy, putting more patients at risk for interprosthetic femur fractures (IPFF). Our study aimed to assess treatment methodologies, implant survivorship, and clinical outcomes of patients with IPFF. 77 patients treated for an IPFF from 1985–2017 at a single large referral center were reviewed. Prior to the fracture, at the hip/knee sites respectively 46 femurs had primary/primary, 21 had revision/primary, 3 had primary/revision and 7 had revision/revision components. Mean age and BMI were 74 years and 30 kg/m2, respectively. Mean follow-up after fracture treatment was 7 years.Introduction
Methods
Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits. A group of 12 skeletally mature rabbits were randomly divided into two groups. One group received subcutaneous (SQ) saline, and a second group received SQ ketotifen injections. Biomechanical data were collected at eight, ten, 16, and 24 weeks. At the time of necropsy, posterior capsule tissue was collected for histopathological and gene expression analyses (messenger RNA (mRNA) and protein).Aims
Methods
Trochanteric fractures account for up to 20% of all periprosthetic fractures occurring during or after total hip arthroplasties (THAs). They are frequently managed conservatively except in cases with significant displacement. There is a paucity of literature describing the indications and results of operative or non-operative management of these fractures. 173 trochanteric fractures occurred in 171 patients, after all primary THAs performed from 1989–2017. Mean age at fracture was 64-years, with 65% being female. Mean follow-up was 7.6-years. Patient's radiographs and Harris Hip Scores (HHS) were recorded. There were 85 (49%) intraoperative and 88 postoperative fractures. Mean time from THA to fracture was 66 months for the postoperative group. 79 (46%) cases were fixed (68 intraoperative, 11 postoperative). Fixation was considered at the discretion of the surgeon. Within the 88 postoperative fractures, 30 were associated with polyethylene wear and osteolysis. 77 were initially treated conservatively and 11 were immediately fixed (8 revisions due to osteolysis, and 3 fracture fixations due to disability associated to displacement >1cm). 19 of the 30 postoperative fractures associated with polyethylene wear and osteolysis, eventually underwent revision.Background
Methods
Metaphyseal cones with cemented stems are frequently used in revision total knee arthroplasties (TKAs). However, if the diaphysis has been previously violated (as in revision of a failed stemmed implant), the resultant sclerotic canal can impair cemented stem fixation, which is vital for cone ingrowth and long-term fixation. We report the outcomes of our novel solution to this problem, in which impaction grafting and a cemented stem in the diaphysis was combined with an uncemented metaphyseal cone for revision TKAs with severely compromised bone. A metaphyseal cone was combined with diaphyseal impaction grafting and cemented stems in a novel fashion for 35 revision TKAs. Mean age at revision TKA was 70 years, with 63% being male. Patients had a mean of 4 prior knee arthroplasty procedures. Indications for the revision with this construct were aseptic loosening (80%) and two-stage re-implantation for periprosthetic infection (PJI; 20%). Mean follow-up was 3 years.Introduction
Methods
Pelvic discontinuity is a challenging complication. One treatment option that has garnered enthusiasm is acetabular distraction. This method obtains stability via distraction of the discontinuity and placement of an oversized socket (± augments) and elastic recoil of the pelvis. The aims of this study were to report implant survivorship, radiographic results, clinical outcomes, and complications of acetabular distraction for pelvic discontinuity in the largest series to date. We retrospectively identified all revision THAs with a Paprosky 3B defect and pelvic discontinuity between 2005 and 2017. Of the 162 patients, 32 were treated with distraction. The mean distraction achieved was 5mm (range, 3–8mm). In addition to distraction with a hemispherical cup, augments were utilized in 3 and cages in 19. The mean age at revision was 68 years with 75% female. Mean follow-up was 3 years.Introduction
Methods
Dual mobility bearings are an attractive treatment option to obtain hip stability during challenging primary and revision total hip arthroplasty (THA) cases. Despite growing enthusiasm in the United States, long-term results of modern dual mobility implants are lacking. The purpose of this study is to analyze data submitted to the American Joint Replacement Registry (AJRR) to characterize utilization trends of dual mobility bearings in the United States. All primary and revision THA procedures reported to AJRR from 2012–2018 were analyzed. Patients of all ages were included and subdivided into dual mobility and traditional bearing surface cohorts. Independent variables included patient demographics, geographic region, hospital size, and teaching affiliation. Associations were determined by chi-square analysis and a logistic regression was performed to assess the association between dual mobility and independent variables.Background
Methods
Revision total knee arthroplasty (revision TKA) occurs for a wide variety of indications and along with revision total hip arthroplasty is billed for using Diagnosis-Related Groups (DRGs) 466, 467, and 468 in the United States. However, DRGs do not account for revision etiology, a potentially substantial driver of cost. This study investigates revision TKA costs and 30-day complications by indication, employing both local granular as well as national standardized databases. Hospitalization costs and complication rates for 1,422 aseptic revision TKAs performed at a high-volume center between 2009 and 2015 were retrospectively reviewed. Additionally, charges for 28,173 revision TKAs in the National Inpatient Sample (NIS) were converted to costs using the Healthcare Cost and Utilization Project cost-to-charge ratios. 30-day complication rates for 3,450 revision TKAs were obtained using the American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP). Costs and complications were compared between revision TKAs performed for the indication of fracture, wear/loosening, and instability with use of simultaneous and pairwise comparisons and a multivariable model accounting for American Society of Anesthesiologists (ASA) score, age, and sex.Introduction
Methods
Cementation of a new liner into an existing well-fixed acetabular component is common during revision total hip arthroplasties (THAs) for many indications, but most commonly for lack of a modern compatible crosslinked polyethylene liner. However, little is known about the long-term durability of this strategy. The purpose of this study was to evaluate the long-term implant survivorship, risk of complications, clinical outcomes, and radiographic results of cementing a new highly cross-linked polyethylene (HXLPE) liner into a well-fixed acetabular component. We retrospectively identified 326 revision THAs where a non-constrained HXLPE liner was cemented into a well-fixed acetabular component. Mean age at revision THA was 63 years, with 50% being female. The most common indications for revision THA were wear and osteolysis (49%), aseptic femoral loosening (35%), and instability (8%). Mean follow-up was 10 years.Introduction
Methods
