Early Radiographic and Clinical Outcomes of an Additive-Manufactured Acetabular Component.

Background: Additive manufacturing has recently gained popularity and is widely adopted in the orthopaedic industry. However, there is a paucity of literature on the radiographic and clinical outcomes of these relatively novel components. The aim of this study was to assess the 2-year clinical and radiographic outcomes of a specific additive-manufactured acetabular component in primary total hip arthroplasty. Methods: We performed a retrospective review of 60 patients who underwent primary total hip arthroplasty with the use of the Stryker's TRIDENT II acetabular component. Evaluation of radiographs was performed at 6 weeks, 1 year, and 2 years postoperatively. Radiographs were evaluated for radiolucencies in Charnley and DeLee zones, signs of biologic fixation, and acetabular inclination and anteversion measurements. Patient-reported outcomes and complications were also obtained. Results: There were no cases of component loosening or changes in component position during follow-up, with an average follow-up time of 1.7 years. A radiolucent line was identified in one patient in zone 1 at 6 weeks; this was absent at 1 year. Radiographic signs of cup biologic fixation were present in 85% of cases by final follow-up. The average inclination was 45.1 (SD = 4.0), and the average anteversion was 26.9 (SD = 5.2). Patient-Reported Outcomes Measurement Information System scores significantly increased at the final follow-up, and there were no complications in this cohort. Conclusions: This study demonstrated excellent radiographic and clinical outcomes with this novel additive-manufactured acetabular component at early follow-up. Although longer-term follow-up is warranted, this additively manufactured highly porous titanium acetabular component demonstrated excellent biologic fixation and reliable fixation at mid-term follow-up.

Discharge to a Skilled Nursing Facility After Hip Fracture Results in Higher Rates of Periprosthetic Joint Infection.

BACKGROUND: Femoral neck fractures (FNFs) in elderly patients are associated with major morbidity and mortality. The influence of postoperative discharge location on recovery and outcomes after arthroplasty for hip fractures is not well understood. METHODS: A multisite retrospective cohort from 9 academic centers identified patients who had FNF treated with hemiarthroplasty or total hip arthroplasty between 2010 and 2019. Patients who had diagnoses of dementia, stroke, age > 80 years, or high energy fracture were excluded. Discharge location was identified, including home-based health services (HHS), inpatient rehabilitation (IPR), or a skilled nursing facility (SNF). Rates of reoperation, periprosthetic joint infection (PJI), and mortality were compared between cohorts. Multivariate logistic regressions were performed, adjusting for age, American Society of Anesthesiologists (ASA) score, body mass index, sex, and tobacco use. Statistical significance was defined as P < .05. RESULTS: A total of 672 patients (315 HHS, 144 IPR, and 213 SNF) were included in this study. The average follow-up was 30 months. The SNF cohort was significantly older (P < .0001) with higher ASA scores (P < .0001) than the HHS cohort. In a logistic regression model adjusting for age, ASA score, and body mass index, the SNF cohort had higher mortality rates than the HHS cohort (P = .0296) and were more likely to have PJI within 90 days (odds ratio = 4.55, 95% confidence interval = 1.40, 4.74) and within 1 year (odds ratio = 3.08, 95% confidence interval = 1.08, 8.78). Time to PJI was significantly shorter in the SNF cohort (SNF 38 versus HHS 231 days, P = .0155). No differences were seen in dislocation or reoperation rates between the SNF and HHS cohorts. No differences were seen in complication rates between the IPR and HHS cohorts. CONCLUSIONS: Discharge to a SNF after arthroplasty for FNF is associated with increased mortality and higher rates of PJI. Hip fracture care pathways that uniformly discharge patients to SNFs may need to be re-evaluated, and surgeons should consider discharge to home with HHS when possible.

The Empty Ischial Fossa Sign: A Visual Representation of Relative Inadequate Anteversion in the Posteriorly Tilted Pelvis.

Background: Instability is a known complication following total hip arthroplasty (THA) and is influenced by spinopelvic alignment. Radiographic markers have been investigated to optimize the acetabular cup position. This study evaluated if the empty ischial fossa (EIF) sign and the position of the trans-teardrop line were predictive of postoperative instability. Methods: All patients who underwent THA from 2011 to 2018 at a single institution were retrospectively reviewed. Pelvic tilt was measured using a trans-teardrop line compared to the superior aspect of the pubic symphysis on standing anteroposterior pelvis radiographs. Postoperative dislocations were identified through chart review and radiographic review. The EIF sign was determined by the presence of uncovered bone below the posterior inferior edge of the acetabular component at the level of the native ischium and posterior wall on standing postoperative anteroposterior radiographs. Results: One thousand seven hundred fifty patients (952 anterior approach and 798 posterior approach) were included. The EIF sign was present in 458 patients (26.2%) and associated with an increased dislocation rate (3.9% vs 0.9%, P < .0001). Patients with spondylosis/instrumented fusion, and positive EIF sign had a dislocation risk of 5.1% vs 1.3% (P = .001). A postoperative outlet pelvis was not significant for increased dislocation risk (odds ratio 2.16, P = .058). Patients with combined spondylosis/fusion, posterior approach, outlet pelvis, and EIF sign had a dislocation rate of 14.5%. Conclusions: The EIF sign was an independent risk factor for postoperative instability and may represent failure to account for pelvic tilt. Avoidance of the EIF sign during cup positioning may help reduce dislocations following THA.

A Novel Method to Calculate Functional Pelvic Tilt Using a Standing Anteroposterior Pelvis Radiograph.

Background: Functional patient-specific acetabular component positioning is important in total hip arthroplasty. We preoperatively evaluate the pelvic tilt (PT) on standing anteroposterior (AP) pelvis radiographs using a novel measurement and then recreate this intraoperatively using imaging. The purpose of this study was to determine if there is a linear correlation between this novel measurement and the actual PT. Methods: A retrospective study of 200 patients was performed, measuring PT on standing lateral radiographs as the angle between the anterior superior iliac spines and the pubic symphysis. On the AP pelvis radiographs, the trans-teardrop (TT) line was drawn between the teardrops. The vertical distance between the TT line and the top of the pubic symphysis (TTPS) was then measured. A ratio was made between the lengths of both lines to account for the overall size of the pelvis (TTPS/TT). Linear regression analysis was then performed between PT and TTPS/TT. Results: There was a strong linear correlation between the TTPS/TT ratio on AP pelvis radiographs and PT on lateral radiographs (r = 0.785, r2 = 0.616, P < .001). On subanalysis of the female cohort, the correlation became even stronger (r = 0.864, r2 = 0.747, P < .001). Using regression analysis, a linear equation was created (PT = 97.32 [TTPS/TT] - 5.51), to calculate the PT using the TTPS/TT ratio. Conclusions: There is a strong linear correlation between the TTPS/TT ratio and PT. Using this information, a surgeon can reliably use the distance between the TT line and the superior pubic symphysis on an AP radiograph to recreate the patient's functional PT intraoperatively, allowing for a more accurate patient-specific placement of the acetabular component.

Displaced Versus Nondisplaced Femoral Neck Fractures: Is Arthroplasty the Answer for Both?

BACKGROUND: Traditionally, nondisplaced geriatric femoral neck fractures (FNFs) have undergone operative fixation, while displaced geriatric FNFs have undergone hip arthroplasty. The purpose of this study was to evaluate differences between outcomes in patients with nondisplaced (Garden I and II) fractures and displaced (Garden III and IV) fractures that were treated with arthroplasty. METHODS: This was a retrospective review of patients who had a minimum of 1 year follow-up from nine academic medical centers who underwent arthroplasty for FNFs between 2010 and 2020. Chi-square, Fisher's Exact, and t-tests were used to compare demographics and outcomes between patients who had a displaced fracture and those who had a nondisplaced fracture. We included 1,620 patients, with 131 in the nondisplaced cohort and 1,497 in the displaced cohort. The mean follow-up in the study was 26.4 months. Both groups were similar in terms of demographic variables. RESULTS: At 1-year follow-up, the overall reoperation rate was 7% and was not different between patients who had nondisplaced compared to displaced FNFs who underwent arthroplasty. Heterotopic ossification (HO) was significantly higher in displaced (23.6%) versus nondisplaced fractures (11.7%) (P = .0021). Operative times and blood loss were higher in nondisplaced than displaced fractures that underwent arthroplasty. CONCLUSION: Hip arthroplasty is an excellent treatment option for nondisplaced and displaced geriatric FNFs with relatively low and similar reoperation rates at 1 year. Compared to previously published reoperation rates of internal fixation of nondisplaced FNFs, hip arthroplasty is a reasonable treatment option for nondisplaced FNFs to potentially decrease reoperations in a frail patient population.

Accelerometer-Based Navigation in Primary Total Knee Arthroplasty Leads to Improved Alignment but No Change in Patient-Reported Outcomes.

BACKGROUND: Computer and accelerometer-based navigation (ABN) tools have demonstrated improved mechanical alignment in primary total knee arthroplasty (TKA). ABN, in particular, is attractive due to avoidance of pins and trackers. Prior literature has yet to demonstrate an associated improvement in functional outcomes using ABN compared to conventional instrumentation (CONV). The purpose of this study was to compare alignment and functional outcomes between CONV and ABN in primary TKA in a large patient series. METHODS: A retrospective study of 1,925 TKAs performed by a single surgeon sequentially was performed. There were 1,223 TKAs performed with CONV and measured resection technique. There were 702 TKAs performed with distal femoral ABN and restricted kinematic alignment goals. We compared radiographic alignment, Patient-Reported Outcomes Measurement Information System scores, rates of manipulation under anesthesia, and needs for aseptic revisions between cohorts. Chi-squared, Fisher's exact, and t-tests were used to compare demographics and outcomes. RESULTS: The ABN cohort had higher rates of neutral alignment postoperatively than the CONV cohort (ABN 74% versus CONV 56%, P < .001). Rates of manipulation under anesthesia (ABN 2.8% versus CONV 3.4%, P = .382) and aseptic revision (ABN 0.9% versus CONV 1.6%, P = .189) were similar. The Patient-Reported Outcomes Measurement Information System physical function (ABN 42.6 versus CONV 42.9, P = .4554), physical health (ABN 63.4 versus CONV 63.3, P = .944), mental health (ABN 51.4 versus CONV 52.7, P = .4349), and pain (ABN 32.7 versus CONV 30.9, P = .256) scores were similar. CONCLUSION: ABN is valuable in its ability to improve postoperative alignment but does not improve complication rates or patient-reported functional outcomes.

Outcomes are Compromised When Revising Patellofemoral Arthroplasties for Patellar Component Failures.

BACKGROUND: Outcomes of patellofemoral arthroplasty (PFA) to total knee arthroplasty (TKA) conversion are reported to be similar to primary cases. The purpose of this study was to determine whether the cause for conversion from PFA to TKA correlated to outcomes when compared to a matched cohort. METHODS: A retrospective chart review was performed to identify aseptic PFA to TKA conversions between 2000 and 2021. A cohort of primary TKAs was matched by patient sex, body mass index, and American Society of Anesthesiology score. Clinical outcomes, including range of motion, complication rates, and patient reported outcomes measurement information systems scores, were compared. Chi-squared, Fisher's Exact, and t-tests were performed. There were 20 PFA to TKA conversions that met inclusion criteria and were matched to 60 primary cases. RESULTS: There were 7 cases revised for arthritis progression, 5 for femoral component failure, 5 for patellar component failure, and 3 for patellar maltracking. PFA to TKA conversions for patellar failure (fracture, component loosening) had worse postoperative flexion (115 versus 127°, P = .023) and more complications of stiffness (40 versus 0%, P = .046) than primary TKAs. Conversions for failed patellar components had worse patient reported outcomes measurement information systems physical function (32 versus 45, P = .0046), physical health (42 versus 49, P = .0258), and pain scores (45 versus 24, P = .0465). No differences were found in rates of infection, manipulations under anesthesia, or reoperations. CONCLUSION: PFA to TKA conversion outcomes were similar to primary TKA, except in patients who had failed patellar components and demonstrated worse postoperative range of motion and patient-reported outcomes. Surgeons should avoid thin patellar resections and extensive lateral releases to minimize patellar failures.

Conservatively Treated Symptomatic Rotator Cuff Tendinopathy May Progress to a Tear.

Purpose: To determine the likelihood of, and risk factors for, progression of rotator cuff tendinopathy to tear on magnetic resonance imaging (MRI) in patients treated conservatively for minimum 1 year. Methods: Patients in the Veterans Health Administration (VHA) Corporate Data Warehouse with a diagnosis of rotator cuff injury and sequential MRI of the same shoulder at least 1 year apart were identified. Presenting MRIs were reviewed to select patients with tendinopathy, while excluding those with a normal appearing cuff, tear, or prior repair. Tear progression was defined as development of a partial or full-thickness tear on follow-up MRI. Chart review was performed for demographic and clinical data. Descriptive statistics and inter-observer and intra-observer reliability were calculated. Discrete and continuous variables were compared between patients who progressed and those who did not using chi-square, Fisher's Exact, Student's t, and Mann-Whitney U-test. Results: In the VHA database, 135 patients had an initial MRI demonstrating rotator cuff tendinopathy. On subsequent MRI at mean 3.4 year follow-up, 39% of patients had progressed to a tear. When grouped on the basis of time between scans as 1 to 2 years, 2 to 5 years, or over 5 years, the rate of progression was 32%, 37%, and 54% respectively. No factors were associated with progression. Conclusions: Among patients with symptomatic rotator cuff tendinopathy that remained symptomatic at a minimum of 1 year and obtained a follow-up MRI, 39% progressed to a partial or full-thickness tear. None of the factors evaluated in this study correlated with progression from tendinopathy to tear. When patients were grouped based on time between scans as 1 to 2 years, 2 to 5 years, or more than 5 years, the rate of progression from tendinopathy to tear was 32%, 37%, and 54%, respectively.

Symptomatic Rotator Cuff Tear Progression: Conservatively Treated Full- and Partial-Thickness Tears Continue to Progress.

Purpose: To determine the likelihood of and risk factors for tear progression among patients with a symptomatic partial or full-thickness rotator cuff tears (RCTs) who return with continued shoulder pain and obtain subsequent magnetic resonance imaging (MRI) and to identify various patient factors and MRI findings associated with rotator cuff tear progression. Methods: We performed a retrospective review of MRI studies from Veteran's Affair patients with conservatively treated partial- or full-thickness rotator cuff tears. Patient characteristics and demographics were obtained via chart review. Tear characteristics were measured on MRI obtained a minimum of 1 year apart. We defined progression as either (1) an increase from a partial to a full-thickness tear or (2) an increase in tear width or retraction of at least 5 mm. Statistical analysis using χ2, Fisher exact, Student t, and Mann-Whitney U test was then performed as appropriate, looking for factors involved in RCT progression. Results: We evaluated 412 MRI studies from 206 Veteran's Affair patients with conservatively treated partial- or full-thickness rotator cuff tears from October 1999 to March 2020. Overall, 61% of RCTs had progressed at a mean of 3.2 ± 2.3 years follow-up. Among all patients, 74% of full-thickness tears progressed in size, 42% of partial-thickness tears progressed in size, and 29% of partial-thickness tears progressed to full-thickness tears. On univariate analysis, full-thickness tears (P < .001), disruption of the anterior rotator cuff cable (P = .001), subscapularis involvement (P = .004), tear retraction (P < .001), and tear width (P < .001) all increased the likelihood of progression. On multivariate analysis, full-thickness tears (P < .001) and subscapularis involvement (P = .045) were correlated with progression. Conclusions: RCTs progress over time in terms of size of tear and from partial- to full-thickness tears. There is an increased risk of tear progression in patients with full-thickness tears when compared with partial-thickness tears along with subscapularis tear involvement. Rates of progression are larger than previously reported rates for both partial- and full-thickness tears, noting that our study population were those patients who continued to be symptomatic from their tears. Level of Evidence: Level IV, prognostic case series.

Anterior-Based Approaches to Total Hip Arthroplasty: Beyond the Learning Curve.

BACKGROUND: Anterior-based approaches for total hip arthroplasty (THA) have gained popularity over the last decade. At our institution, anterior-based approaches are preferentially utilized, including both anterior-based muscle-sparing (ABMS) and direct anterior (DA) for primary THA. As there are higher complication rates during the transition to an anterior approach, we compared the outcomes and complications between ABMS and DA approaches beyond the learning curve. METHODS: A retrospective study of all ABMS and DA primary THA patients performed at a single institution was performed, excluding the first 100 anterior cases done by any surgeon. In total, 813 DA and 378 ABMS THA cases were included. Demographics, complications, and patient-reported outcomes (PROMIS and HOOS) were obtained for each patient. RESULTS: There was a 4.5% overall complication rate (4.1% in DA and 5.6% in ABMS, P = .248), with the most common complication being infection at 1.7% (1.5% vs 2.1%, P = .423). A revision was performed in 3.4% of cases overall (1.8% aseptic, 1.6% septic). There was no difference in complication rates between approaches. Length of surgery was shorter for ABMS (94.5 vs 116.0 minutes, P < .001). Both DA and ABMS had significant improvements in PROMIS and HOOS Jr. scores, without any significant difference between the groups. CONCLUSIONS: Anterior-based approaches for primary THA demonstrated excellent clinical results and low complication rates overall. Beyond the learning curve, excellent results can be obtained with either ABMS or DA approach for primary THA.

Occupational Hazards to the Joint Replacement Surgeon: Radiation Exposure.

BACKGROUND: Intraoperative fluoroscopy is an essential tool to assist orthopedic surgeons in accurately and safely implanting hardware. In arthroplasty cases, its use is on the rise with the increasing popularity of the direct anterior (DA) approach for THA. However, exposure of ionizing radiation poses a potential health risk to surgeons. While the benefits of intraoperative fluoroscopy in DA THA is becoming clearer, and are well-described in the literature, the potential health dangers associated with career-long cumulative radiation exposure are rarely discussed. METHODS: In this article, we review the available literature to discuss radiation safety in orthopedics with a focus on total joint arthroplasty. We present the basic science of radiation, discuss the amount of radiation exposure in orthopedic surgery, and review the potential health risks associated with long-term exposure. CONCLUSION: Overall, the radiation dose exposure to arthroplasty surgeons is low and within recommendations for occupation exposure limits. However, due to the stochastic health impacts of ionizing radiation, there is no threshold dose below which radiation exposure is truly safe. Therefore, it is imperative that surgeons practice proper fluoroscopy safety habits, such as wearing proper protective equipment, minimizing fluoroscopy time and magnification, and maximizing distance from the radiation source to minimize the life-long cumulative radiation exposure and associated health risks.

Neocortex Formation in a Tapered Wedge Stem is Not Indicative of Complications or Worse Outcomes.

BACKGROUND: The formation of sclerotic bone, a neocortex, distally surrounding total hip arthroplasty (THA) stems may commonly be seen on radiographs around proximally porous coated stems but can be confused with loosening. The goal of this study was to determine the prevalence of the neocortex finding and whether it associated with worse outcomes after THA. METHODS: A retrospective review of 825 patients with a single tapered wedge stem was performed. Radiographs at 1-year, as well as final follow-up were reviewed for evidence of sclerotic bone (neocortex) surrounding the stem in all 14 Gruen zones. The final attending radiology read of lucency was also recorded. Patients were grouped by the presence of the neocortex. PROMIS Physical Function scores and complications were compared between neocortex groups. RESULTS: The neocortex group had 558 (68%) patients compared to 267 (32%) in the no neocortex group. The most common Gruen zones for evidence of neocortex were 10 (55%), 11 (52%), and 12 (51%). Seven percent of patients had a finding of lucency on radiology read. There was no difference between groups in terms of dislocations (P = .61), infection (P = .79), fracture rates (P = .54), revision surgery (P = .73), and reoperation for any cause (P = .62). PROMIS PF scores were significantly higher in the neocortex group (P < .0001). CONCLUSION: The presence of a distal neocortex is a common finding on radiographs after THA with this proximally porous-coated tapered wedge stem and does not portend worse outcomes, nor is it a sign of aseptic loosening, increased revision rates, infection, dislocation, or periprosthetic fracture risk.

Managing Hip-Spine Concepts in the Direct Anterior Approach With Use of Fluoroscopy.

BACKGROUND: The spinopelvic relationship in regard to total hip arthroplasty has become a topic of increasing interest in recent years. Hip arthritis and a stiff lumbar spine create a situation where the spinopelvic junction has decreased mobility, which in turn increases the risk of instability after total hip arthroplasty as the femoral acetabular joint must undergo increased motion. Regardless of the approach, surgeons should be aware of the risk of instability in patients with a stiff spinopelvic junction and the necessary modifications to component positioning to avoid postoperative instability. As many direct anterior approach surgeons use fluoroscopy for intraoperative navigation, anterior approach surgeons must also understand how to best use this technology to improve component positioning. METHODS: In this article, we address the basic concepts surrounding spinopelvic stiffness, the intraoperative component adjustments necessary for optimizing stability, and how to appropriately use fluoroscopy for navigation in the direct anterior approach. CONCLUSIONS: Appropriate use of intraoperative fluoroscopy includes understanding the impact of parallax and distortion, properly recreating the patient's standing functional pelvic plane intraoperatively and adjusting the cup's target position based on a preoperative understanding of the patient's spinopelvic motion.

Conjoint tendon release for persistent anterior shoulder pain following reverse total shoulder arthroplasty.

BACKGROUND: Persistent anterior shoulder pain is an under-reported complication after reverse total shoulder arthroplasty (RTSA). The purpose of this study was to determine the effectiveness of open conjoint tendon release in patients with anterior shoulder pain due to conjoint tendinitis after RTSA. METHODS: Open conjoint tendon release was performed by the senior author from June 2014 to November 2018 in patients with persistent anterior shoulder pain after RTSA. Patients were evaluated preoperatively and at a minimum of 1 year postoperatively by phone interview with patient-reported outcome scores including a visual analog scale score for pain and the American Shoulder and Elbow Surgeons score. RESULTS: We evaluated 11 of 12 patients (92% follow-up) at a minimum of 1 year (average, 27 ± 11 months) after conjoint tendon release. American Shoulder and Elbow Surgeons and visual analog scale pain scores improved from 29.0 ± 22.1 and 7.3 ± 2.0, respectively, preoperatively to 58.2 ± 30.6 and 3.1 ± 3.5, respectively, postoperatively, after open conjoint tendon release (P = .02 and P = .003, respectively). Of the patients, 45% (5 of 11) reported improvement but with some coracoid pain after the release whereas 55% (6 of 11) reported no coracoid pain after the release. No complications occurred as a result of the release, and no patients required reoperation. CONCLUSION: Our results suggest that conjoint tendinitis may be a cause of persistent postoperative anterior shoulder pain after RTSA and open conjoint tendon release is a successful treatment.