Effect of inverse kinematic alignment total knee arthroplasty on coronal alignment of the ankle joint in patients with varus knee deformity.

INTRODUCTION: Varus or valgus knee deformities influence ankle coronal alignments. The impact of Total Knee Arthroplasty (TKA) on ankle joint alignment has not been entirely illustrated. Inverse Kinematic Alignment (iKA) is a surgical philosophy that aims to restore soft tissue balance, function, and native anatomy within validated boundaries to restore restrictive native kinematics. Therefore, this study aimed to investigate the postoperative association of patient-specific alignment on the coronal alignment of the ankle in patients with varus knee deformity who underwent iKA TKA. We hypothesized that greater preoperative varus malalignments would correlate with significant postoperative ankle coronal alignment changes. METHODS: This retrospective study of a prospective collected cohort assessed patients who underwent imageless navigation assisted robotic TKA using a single implant design for primary osteoarthritis between January 2022 and August 2023. Preoperative and postoperative full-length standing anteroposterior X-ray imaging was used to measure Hip-Knee-Ankle (HKA), Tibial Plafond Inclination (TPI), Talar inclination (TI), and Tibiotalar Tilt (TTT) angles. Patients were subsequently divided into groups of neutral varus) < 10°) and severe varus (≥ 10°) according to the preoperative HKA angle. RESULTS: Significant changes in preoperative and postoperative HKA angles were found in the severe varus (14.5° vs. 6.4°, p < 0.001) group. Changes were also significant between preoperative and postoperative TPI and TI angles in the severe varus group; however, TTT did not reach statistical significance. Delta change from pre- to postoperative HKA was significantly higher for the severe varus group (8.1° vs. 0.8°, p < 0.019). Delta change of TPI, TI and TTT did not differ between groups. CONCLUSION: Coronal knee alignment after TKA affects coronal alignment of the ankle. iKA technique in TKA for varus knee deformity preserves or minimizes substantial coronal alignment changes of the ankle joint. These findings may add to the benefits reported for patient specific alignment TKA techniques. LEVEL OF EVIDENCE: III.

Higher rates of intraoperative fractures with compaction broaching compared to conventional broaching during hip hemiarthroplasty for femoral neck fractures.

PURPOSE: Intraoperative periprosthetic femoral fracture (IPFF) is a known iatrogenic complication during hemiarthroplasty (HA) which may lead to inferior outcomes. The risk factors for IPFF during HA in displaced femoral neck fractures (FNF) remains to be fully elucidated. This study aims to compare IPFF rates between compaction broaching and conventional broaching techniques for cementless HA in FNF. METHODS: We retrospectively reviewed institutional surgical data of patients who underwent cementless HA for displaced FNF from January 2010 to January 2022. Patients were stratified into two groups based on the broaching system: conventional broaching and compaction broaching. The presence, location, and treatment of IPFF were assessed for both groups. Effect of IPFF on postoperative weight-bearing status, mortality readmission and revision rates were compared between groups. RESULTS: A total of 1,586 patients included in the study. 1252 patients (78.9%) in the conventional broaching group and 334 patients (21.1%) in the compaction broaching group. A total of 104 IPFF were found (6.5%). As compared to conventional broaching, compaction broaching was associated with significant higher IPFF rates (12.9% vs. 4.9%, p < 0.001, OR 2.84, CI 1.88-4.30). The location of the IPFF was similar between groups (p = 0.366), as well as the intraoperative treatment (p = 0.103) and postoperative weight-bearing status (p = 0.640). Surgical time, mortality rates, readmission rates and revision rates were comparable between groups. In a multivariate regression analysis, compaction broaching (OR, 4.24; p < 0.001) was independently associated with IPFF. CONCLUSIONS: This study reveals higher rates of IPFF associated with compaction broaching. Although this finding may have minimal clinical relevance, surgeons should consider these results when considering implant selection.

Mid-term outcomes of total hip arthroplasty in patients younger than 30 years.

INTRODUCTION: Total hip arthroplasty (THA) has predominantly been utilized to treat older patients with primary osteoarthritis. However, recent improvements in surgical technique and implant materials have increased implant longevity, making THA a viable option for younger patients (< 30 years old). While trend analyses indicate an expanding utilization of THA in younger patients with non-OA diagnoses, current data on mid- and long-term THA outcomes in this population are limited. This study aims to describe the demographics, perioperative data, and implant survivorship of patients younger than 30 years undergoing THA. METHODS: A retrospective study across two large urban academic medical institutions identified 135 patients aged < 30 years who underwent 155 primary THAs between 2012 and 2017, with up to 10-year clinical follow-up. Baseline demographics, surgical indications, intraoperative details, and postoperative outcomes were analyzed. RESULTS: The mean age at surgery was 24.9 years (range 18-29). Osteonecrosis of the femoral head (55.5%), developmental hip dysplasia (28.3%), and arthritis (15.5%) were the primary indications. Most surgeries utilized the posterior approach (64.5%), manual technique (65.8%), and Ceramic-on-Polyethylene articulation (71.6%). Seven patients (4.5%) were readmitted within 90-days of surgery, including three non-orthopedic-related readmissions (1.9%) and four orthopedic-related readmissions (2.6%). Dislocations were reported in two patients (1.3%). There were six all-cause revisions (3.9%), four aseptic (2.6%) and two septic (1.3%). Kaplan-Meier analysis showed 10-year survival from implant retaining reoperation was 98.7%, 10-year survival from all-cause revision was 96.1%, and 10-year survival from aseptic revision was 97.4%. CONCLUSION: With a 10-year aseptic implant survivorship rate of 97.4%, THA is a reliable surgical intervention for patients younger than 30 years of age who have severe hip pathology. Further studies are warranted for a more comprehensive understanding of mid- and long-term survivorship risk factors in this demanding population, facilitating improved risk assessment and informed surgical decisions.

Better restoration of joint line obliquity in tibia first restricted kinematic alignment versus mechanical alignment TKA.

INTRODUCTION: In total knee arthroplasty (TKA), suboptimal restoration of joint line obliquity (JLO) and joint line height (JLH) may lead to diminished implant longevity, increased risk of complications, and reduced patient reported outcomes. The primary objective of this study is to determine whether restricted kinematic alignment (rKA) leads to improved restoration of JLO and JLH compared to mechanical alignment (MA) in TKA. MATERIALS AND METHODS: This retrospective study assessed patients who underwent single implant design TKA for primary osteoarthritis, either MA with manual instrumentation or rKA assisted with imageless navigation robotic arm TKA. Pre- and post-operative long standing AP X-ray imaging were used to measure JLO formed between the proximal tibial joint line and the floor. JLH was measured as the distance from the femoral articular surface to the adductor tubercle. RESULTS: Overall, 200 patients (100 patients in each group) were included. Demographics between the two groups including age, sex, ASA, laterality, and BMI did not significantly differ. Distribution of KL osteoarthritis classification was similar between the groups. For the MA group, pre- to post-operative JLO significantly changed (2.94° vs. 2.31°, p = 0.004). No significant changes were found between pre- and post-operative JLH (40.6 mm vs. 40.6 mm, p = 0.89). For the rKA group, no significant changes were found between pre- and post-operative JLO (2.43° vs. 2.30°, p = 0.57). Additionally, no significant changes were found between pre- and post-operative JLH (41.2 mm vs. 42.4 mm, p = 0.17). Pre- to post-operative JLO alteration was five times higher in the MA group compared to the rKA group, although this comparison between groups did not reach statistical significance (p = 0.09). CONCLUSION: rKA-TKA results in high restoration accuracy of JLO and JLH, and demonstrates less pre- and post-operative JLO alteration compared to MA-TKA. With risen interest in joint line restoration accuracy with kinematic alignment, these findings suggest potential advantages compared to MA. Future investigation is needed to correlate between joint line restoration accuracy achieved by rKA and enhanced implant longevity, reduced risk of post-operative complications, and heightened patient satisfaction.

The impact of posterior-stabilized vs. constrained polyethylene liners in revision total knee arthroplasty.

AIM: Posterior stabilized (PS) and varus valgus constrained (VVC) knee polyethylene liners have been shown to confer excellent long-term functional results following revision total knee arthroplasty (rTKA). The purpose of this study was to compare outcomes of patients who underwent rTKA using either a PS or VVC liner. METHODS: A retrospective comparative study of 314 rTKA with either PS or VVC liner and a minimum follow-up time of two years was conducted. Patient demographics, complications, readmissions, and re-revision etiology and rates were compared between groups. Kaplan-Meier survivorship analysis was performed to estimate freedom from all-cause revision. RESULTS: Hospital LOS (3.41 ± 2.49 vs. 3.34 ± 1.93 days, p = 0.793) and discharge disposition (p = 0.418) did not significantly differ between groups. At a mean follow-up of 3.55 ± 1.60 years, the proportion of patients undergoing re-revision did not significantly differ (19.1% vs. 18.7%, p = 0.929). In subgroup analysis of re-revision causes, the VVC cohort had superior survival from re-revision due to instability compared to the PS cohort (97.8% vs. 89.4%, p = 0.003). Freedom from re-revision due to aseptic loosening did not significantly differ between groups (85.2% vs. 78.8%, p = 0.436). Improvements in range of motion (ROM) from preoperative to latest follow-up were similar as well. CONCLUSIONS: PS and VVC liners confer similar survivorship, complication rates, and overall knee ROM in rTKA. VVC liners were not associated with increased postoperative aseptic loosening and demonstrated superior freedom from re-revision due to instability. Future studies with longer follow-up are warranted to better determine significant differences in clinical outcomes between the two bearing options. LEVEL III EVIDENCE: Retrospective Cohort Study.

Does addition of gentamicin for antibiotic prophylaxis in total knee arthroplasty reduce the rate of periprosthetic joint infection?

BACKGROUND: First-generation cephalosporins are used as antibiotic prophylaxis in total joint arthroplasty patients. However, this regimen does not address Gram-negative bacteria causing periprosthetic joint infection (PJI). Previous studies have suggested that the addition of an aminoglycoside as antibiotic prophylaxis in THA reduces surgical site infection (SSI), and less is known on its effect in TKA. This study aimed to investigate if the addition of a single-dose gentamicin, administered pre-operatively, is associated with lower rates of infection in TKA patients. PATIENTS AND METHODS: This is a retrospective study of patients who underwent primary TKA as treatment for osteoarthritis between January 2011 and April 2021, with a minimum 1-year follow-up. The mean age was 69.9 (± 9.8), the mean BMI was 29.7 (± 5.5), and most patients had American Society of Anaesthesiology (ASA) score of 2-3 (92.9%). Patients were stratified based on the peri-operative antibiotic prophylaxis they received: cefazolin with addition of gentamicin (case group) or cefazolin (control group). Our primary study endpoints were rates of PJI and SSI, which were compared between groups using the chi-square test. Statistical significance was set as p < 0.05. RESULTS: The final study population consisted of 1590 patients, 1008 (63.4%) in the control group and 582 (36.6%) patients in the case group. The total infection rate for patients that received gentamicin dropped by 34%; however, this finding did not reach statistical significance (1.3% (control) vs. 0.86% (case), p = 0.43). The same drop was seen after subdivision of infections to PJI (0.5% vs. 0.34%, 32% drop, p = 0.66) and SSI (0.8% vs. 0.52%, 35% drop, p = 0.52). CONCLUSIONS: A single dose of gentamicin administered pre-operatively to a standard antibiotic prophylaxis was not associated with a statistically significant lower rate of PJI. Although the difference in infection rate did not reach statistical significance, the current study noted a drop in the rate of infection by 1/3 in the gentamicin cohort. Further investigation to evaluate the potential benefit of adding gentamicin to a peri-operative antibiotic regimen is warranted.

Increased postoperative glycemic variability is associated with increased mortality in diabetic patients undergoing hip arthroplasty for hip fracture.

BACKGROUND: Increased glycemic variability (GV) during hospitalization has been associated with increased rates of surgical site and periprosthetic joint infections (PJI) following elective total joint arthroplasty. Uncertainty exists surrounding GV as a predictor for complications in urgent arthroplasty cases following hip fractures. In this study, we evaluated the association between GV and postoperative complications in diabetic patients undergoing total hip arthroplasty (THA) and hemiarthroplasty (HA) for hip fractures. METHODS: We analyzed data on 2421 consecutive patients who underwent THA or HA at our institution from 2011 to 2020. Patients with a known diagnosis of diabetes mellitus who had a minimum of three postoperative glucose values taken within the first week after surgery were included. GV was assessed using a coefficient of variation. Outcomes included short- and long-term mortality, reoperations, prosthetic joint infection (PJI) requiring revision and readmissions for any cause. RESULTS: The final cohort consisted of 482 patients (294 females, 188 males). Higher GV was associated with an increased 90-day mortality (p = 0.017). GV was not associated with 30-day mortality (p = 0.45), readmissions of any cause at 30 or 90 days (p = 0.99, p = 0.91, respectively), reoperation of any cause (p = 0.91) or PJI requiring revision surgery (p = 0.42). CONCLUSIONS: Higher GV in the postoperative period is associated with increased rates of mortality in diabetic patients following THA and HA for hip fractures. Efforts should be made to monitor and control glucose variability in the postoperative period.

Comparison of canal fill and radiolucent line formation between two fully coated, hydroxyapatite tapered stems: a 2-year follow-up after total hip arthroplasty.

INTRODUCTION: Comparison between fully hydroxyapatite (HA)-coated stems with differing geometry are lacking in the total hip arthroplasty (THA) literature. This study aimed to compare femoral canal fill, radiolucency formation, and 2-year implant survivorship between two commonly used, HA-coated stems. METHODS: All primary THAs performed with two fully HA-coated stems (Polar stem, Smith&Nephew, Memphis, TN and Corail stem, DePuy-Synthes, Warsaw, IN) with a minimum 2-year radiographic follow-up were identified. Radiographic measures of proximal femoral morphology based on the Dorr classification and femoral canal fill were analyzed. Radiolucent lines were identified by Gruen zone. Perioperative characteristics and 2-year survivorship were compared between stem types. RESULTS: A total of 233 patients were identified with 132 (56.7%) receiving the Polar stem (P) and 101 (43.3%) receiving the Corail stem (C). No differences were observed with respect to proximal femoral morphology. Femoral stem canal fill at the middle third of the stem was greater for P stem patients than for C stem patients (P stem; 0.80 ± 0.08 vs. C stem; 0.77 ± 0.08, p = 0.002), while femoral stem canal fill at the distal third of the stem and presence of subsidence were comparable between groups. A total of six and nine radiolucencies were observed in P stem and C stem patients, respectively. Revision rate at 2-year (P stem; 1.5% vs C stem; 0.0%, p = 0.51) and latest follow-up (P stem; 1.5% vs C stem; 1.0%, p = 0.72) did not differ between groups. CONCLUSION: Greater canal fill at the middle third of the stem was observed for the P stem compared to the C stem, however, both stems demonstrated robust and comparable freedom from revision at 2-year and latest follow-up, with low incidences of radiolucent line formation. Mid-term clinical and radiographic outcomes for these commonly used, fully HA-coated stems remain equally promising in THA despite variations in canal fill.

Addressing posterior tilt displacement during surgery to lower failure risk of sub-capital Garden types 1 and 2 femoral fractures.

INTRODUCTION: Sub-capital femoral fractures (SCFF) are impacted or non-displaced in Garden types 1 and 2, respectively. Non-surgical treatment is protected weight-bearing combined with physiotherapy and radiographic follow-up in selected patients. Traditionally, in situ pinning is the surgical treatment of choice. The aim of this study was to estimate whether the valgus deformity in Garden types 1 and 2 (AO classification 31B1.1 and 31B1.2) SCFF is a virtual perception of a posterior tilt deformity and if addressing this deformity improves patients' outcomes. MATERIALS AND METHODS: The records of 96 patients with Garden Types 1 and 2 SCFF treated in tertiary medical center between 1/2014 and 9/2017 were retrospectively reviewed. They all had preoperative hip joint anteroposterior and lateral radiographic views. 75 patients had additional computed tomography (CT) scans. Femoral head displacement was measured on an anteroposterior and axial radiograph projections and were performed before and after surgery. Preoperative 3D reconstructions were performed for a better fracture characterization, and assessment of the imaging was performed by the first author. RESULTS: The average age of the study cohort was 73 years (range 28-96, 68% females). There were 58 right-sided and 38 left-sided fractures. Ninety patients had Type 1 and six patients had Type 2 fractures. The average preoperative posterior tilt was 15 degrees and the average valgus displacement was 10 degrees on plain radiographs compared to 28 degrees and 11 degrees, respectively, on CT scans. Posterior tilt was found with a virtual perception as valgus-impacted fractures. The postoperative posterior tilt was corrected to an average of 3 degrees and the valgus displacement to 5 degrees. CONCLUSION: CT provides an accurate modality for measuring femoral head displacement and fracture extent. The posterior tilt displacement should be addressed during surgery to lower failure risk and the need for additional procedures. IRB APPROVAL: TLV-0292-15. LEVEL OF EVIDENCE: IV.

Good clinical and radiological outcomes of the varus-valgus constrained mobile-bearing implant in revision total knee arthroplasty.

PURPOSE: Knee instability is one of the most common indications for having to undergo revision total knee arthroplasty (RTKA) and can be prevented with adequate implant selection and good surgical technique. Varus-valgus constrained implants (VVC) are indicated for cases of RTKA with absent ligament function in order to provide the necessary stability. While mobile-bearing articulations are thought to decrease the risk of aseptic loosening in comparison to their fixed-bearing counterparts, there is limited data on their outcomes. The purpose of our study is to present the clinical and radiological outcomes for patients undergoing an RTKA procedure with the mobile-bearing VVC implant. METHODS: Between January 2008 to January 2018, 93 patients underwent RTKA with the use of varus-valgus mobile-bearing (VVCMB) prosthesis. The main indications for RTKA were instability 38.7% (n = 36), aseptic loosening 31.2% (n = 29), infection in 26.9% (n = 25), and other 3.3%. The mean follow-up time was 56 months. Clinical outcomes were assessed by knee society scores, range of motion, and rate of re-operation. RESULTS: The mean knee society score increased significantly from 65.52 pre-operatively to 89.65 post-operatively (p < 0.001). The five year cumulative incidence of re-operation in our study was 7.53% (n = 7). Our study reported no cases of aseptic loosening or mobile-bearing spin-out. The number of flexion contractures decreased from n = 23 (24.7%) pre-operatively to n = 11 (11.8%) post-operatively (p < 0.05). CONCLUSION: The VVC mobile-bearing prosthesis demonstrated good clinical outcomes and mid-term survivorship in patients undergoing RTKA. Additional follow-up is required in the long term.

Digital templating in total hip arthroplasty using contralateral healthy hip results in decreased accuracy.

The accuracy of pre-operative digital templating for total hip arthroplasty (THA) using the diseased versus unaffected contralateral joint remains unclear. As such, we devised a study to compare templating precision between the operated hip joint versus the healthy side for patients with osteoarthritis (OA). The study hypothesis was that preoperative templating accuracy of THA on the ipsilateral diseased hip joint would be higher compared to the contralateral healthy hip in patients with OA. We retrospectively reviewed 100 patients who underwent THA for unilateral OA at our center from January 2018 to January 2020. Retrospective preoperative digital templating was performed separately on both the operated hip joint and the healthy contralateral hip joint by a single surgeon who was blinded by the in-situ components sizes. Accuracy of each group was compared to the implanted components. Assessment of the 100 included cases demonstrated superior acetabular component size prediction when templating was performed using the diseased hip compared to the healthy contralateral side (68.0% versus 51.0%, p<0.001). No differences between the cohorts were found regarding templating accuracy of femoral stem sizes (72.0% and 69.0%, p=0.375) or neck offset (73.0% and 69.0%, p=0.289). Templating acetabular cup size using the ipsilateral diseased hip is more accurate than using the contralateral healthy hip in patients with unilateral OA.

Effects of surgeon experience and patient characteristics on accuracy of digital pre-operative planning in total hip arthroplasty.

BACKGROUND: The effect of surgeon experience on accuracy of digital pre-operative planning for total hip arthroplasty (THA) remains unclear. The aims of our study were to compare pre-operative planning accuracy between fellow-trained orthopaedic surgeons and residents and to explore whether surgery indication effects the prediction accuracy. METHODS: We prospectively reviewed 101 patients who underwent pre-operative digital templating for THA in our center from January 2019 to January 2020 with King Mark device. Extracted data included baseline characteristics and indication for primary arthroplasty. Pre-operative digital templating was performed separately by both a fellow-trained surgeon and a resident. Accuracy of each group was compared with the implanted components. RESULTS: The overall adequate pre-operative planning of the acetabular cup (exact or +/-1 size match) by the fellow-trained group was higher compared with the resident's group (77.2 and 64.3% respectively, p = 0.037), whereas the overall adequate pre-operative planning of the femoral stem (exact or +/-1 size match) was higher in the resident's group compared with the fellow-trained group (83.2 and 61.4% respectively, p < =0.001). The fellow-trained group showed better pre-operative planning of complex cases (developmental dysplasia of the hip and avascular necrosis of femoral head) than the resident's group. CONCLUSIONS: The experience of the planner does not significantly affect the accuracy of correctly predicting component sizes. However, in complex cases, fellow-trained surgeons should assist residents in digital pre-operative templating for THA.

Is continuation of anti-platelet treatment safe for elective total hip arthroplasty patients?

INTRODUCTION: Acetylsalicylic acid (aspirin) is a commonly prescribed medication, especially in the age group of individuals who undergo elective total hip arthroplasty (THA). Preoperative discontinuation of aspirin is believed to reduce intraoperative bleeding and other complications, but it may increase the risk of perioperative cardiovascular events. In this study we have sought to evaluate the safety of continuous aspirin treatment in patients undergoing elective THA. MATERIALS AND METHODS: This is a retrospective analysis of a consecutive cohort who underwent elective THA in a tertiary medical center between 2011 and 2018. The cohort was divided into two groups-one that received continuous preoperative aspirin treatment and one that did not. Blood loss, peri- and postoperative complications, readmissions, and short- and long-term mortality were compared between groups. RESULTS: Out of 757 consecutive patients (293 males, 464 females) who underwent elective primary THA, 552 were in the "non-aspirin" group and 205 were in the "aspirin" group and were not treated preoperative with other medication affecting hemostasis. Perioperative continuation of aspirin treatment did not significantly increase perioperative bleeding, as indicated by changes in hemoglobin levels (P = 0.72). There were no significant differences in short- and long-term mortality (P = 0.47 and P = 0.4, respectively) or other perioperative complications, such as readmission (P = 0.78), deep or superficial infection (P = 1 and P = 0.47, respectively), and cardiovascular events (none in both groups). CONCLUSION: Peri-operative continuation of aspirin treatment in patients undergoing elective primary THA did not increase perioperative complications or mortality compared to the non-aspirin-treated patients. The protective effects of aspirin from postoperative thrombotic and cardiovascular events are well documented. The current findings dispute the need to preoperatively withhold aspirin treatment in patients undergoing elective primary THA.

Total Hip Arthroplasty in Human Immunodeficiency Virus-Positive Patients: A Concise Follow-Up at 10 to 14 Years.

BACKGROUND: Advancements in the management of human immunodeficiency virus (HIV) now permit HIV-positive patients to have longer life spans, increasing their cumulative risk of developing an advanced degenerative joint disease, necessitating total hip arthroplasty (THA). The purpose of this study was to provide an extended follow-up on a previously published study on a cohort of HIV-positive THA recipients in an effort to confirm the safety and longevity of THA in this population. METHODS: This study is a follow-up on a previous study comprised of 41 hips in 31 HIV-positive THA recipients. At this follow-up, 5 patients from the original cohort required contralateral THA. Postoperative complications were recorded up to the patient's last follow-up date. A survivorship analysis was performed using the Kaplan-Meier method with revision THA as the end point. RESULTS: Since the last report, 2 additional hips were revised (one for aseptic loosening and one for a periprosthetic fracture), and 5 patients underwent contralateral THA. This resulted in a total of 5 (13.8%) hips requiring revision THA at the latest follow-up. The mean follow-up interval for the original cohort and for the contralateral 5 hips was 78.9 ± 50.2 months and 54.6 ± 45.3 months, respectively. Kaplan-Meier survivorship analysis with revision THA for any reason as the end point demonstrated survivorship of 93% (2 years), 90% (5 years), and 81% (10 and 14 years) after primary THA, respectively. CONCLUSION: Our study suggests that it is possible to achieve a low incidence of postoperative infection in HIV-positive THA recipients. In addition, our study demonstrates that non-hemophiliac HIV-positive patients have comparable revision rates to previously published reports on HIV-negative patients of similar age, underscoring the clinical efficacy of highly active antiretroviral therapy.

Surgical approach for open reduction and internal fixation of clavicle fractures: a comparison of vertical and horizontal incisions.

PURPOSE: This study was designed to compare the results of clavicle fracture open reduction internal fixation (ORIF) with standard horizontal incision versus vertical incision. METHODS: ORIF surgery performed between October 2012 and August 2016 was included. The surgical approach was chosen according to surgeon preference as vertical or horizontal. Functional outcomes, fracture union, complications, scar appearance, skin irritation, and denervation around the scar were assessed at a minimum follow-up of three months. RESULTS: Thirty-eight patients, age 39 ± 12 years, were operated upon, 22 through vertical incisions and 16 through horizontal incisions. There were no significant group differences in functional scores, fracture union, or complications. Two patients in the vertical incision group had a post-operative haematoma. The scar length was significantly shorter when a vertical incision was used (6.75 ± 1.25 cm vs 8.9 ± 2.3 cm, P = 0.001). The typical distribution of hypoesthetic skin area distal and lateral to the scar represented iatrogenic damage to the supraclavicular nerves and was found in 66% of patients. The mean hypoesthetic surface area was smaller in the vertical incision group (38 ± 29 cm2 vs 48 ± 28 cm2, P = non-significant). CONCLUSION: Vertical incision results in shorter scars but may be associated with increased incidence of haematomas. Meticulous closure of the subcutaneous tissue is recommended.

Inhibition of nucleotide pyrophosphatase/phosphodiesterase 1: implications for developing a calcium pyrophosphate deposition disease modifying drug.

Objectives: Calcium pyrophosphate deposition (CPPD) is associated with osteoarthritis and is the cause of a common inflammatory articular disease. Ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (eNPP1) is the major ecto-pyrophosphatase in chondrocytes and cartilage-derived matrix vesicles (MVs). Thus, eNPP1 is a principle contributor to extracellular pyrophosphate levels and a potential target for interventions aimed at preventing CPPD. Recently, we synthesized and described a novel eNPP1-specific inhibitor, SK4A, and we set out to evaluate whether this inhibitor attenuates nucleotide pyrophosphatase activity in human OA cartilage. Methods: Cartilage tissue, chondrocytes and cartilage-derived MVs were obtained from donors with OA undergoing arthroplasty. The effect of SK4A on cell viability was assayed by the XTT method. eNPP1 expression was evaluated by western blot. Nucleotide pyrophosphatase activity was measured by a colorimetric assay and by HPLC analysis of adenosine triphosphate (ATP) levels. ATP-induced calcium deposition in cultured chondrocytes was visualized and quantified with Alizarin red S staining. Results: OA chondrocytes expressed eNPP1 in early passages, but this expression was subsequently lost upon further passaging. Similarly, significant nucleotide pyrophosphatase activity was only detected in early-passage chondrocytes. The eNPP1 inhibitor, SK4A, was not toxic to chondrocytes and stable in culture medium and human plasma. SK4A effectively inhibited nucleotide pyrophosphatase activity in whole cartilage tissue, in chondrocytes and in cartilage-derived MVs and reduced ATP-induced CPPD. Conclusion: Nucleotide analogues such as SK4A may be developed as potent and specific inhibitors of eNPP1 for the purpose of lowering extracellular pyrophosphate levels in human cartilage with the aim of preventing and treating CPPD disease.

Up to 18-Year Follow-Up Wear Analysis of a First-Generation Highly Cross-Linked Polyethylene in Primary Total Hip Arthroplasty.

BACKGROUND: The advent of highly cross-linked polyethylene (HCLPE) has significantly improved total hip arthroplasty survivorship. HCLPE has been shown to improve wear properties in midterm outcomes when compared to traditional polyethylene liners; however, there is a paucity of studies evaluating long-term outcomes. In addition, there is concern that wear rates may accelerate as the implant ages. Thus, the aims of this study are to report on the longest-to-date follow-up of a specific first-generation HCLPE liner and to determine whether there is a change in the annual wear rate over time. METHODS: Forty hips in 38 patients which were previously reported on in a midterm study were included in this long-term follow-up study. Patients in this cohort all received total hip arthroplasty between March 1999 and August 2004 using the Crossfire HCLPE liner. Annual wear rates (mm/y) were calculated for this cohort. Patients were contacted and asked about complications or revision procedures they may have had since the index procedure. RESULTS: Clinical follow-up averaged 12.9 years with a range of 7-18 years. The average follow-up duration was 12.5 years with a range of 10-17 years. Linear wear was found to be 0.056 ± 0.036 mm/y. Osteolysis was not observed in any of the patients with greater than 10-year radiographic follow-up. Furthermore, only 1 patient required revision surgery following a mechanical fall. CONCLUSION: Our study demonstrates the long-term wear rates associated with HCLPE liners continue to match rates published in midterm studies. Previously, we have reported that this cohort had an average annual wear rate of 0.05 mm/y over 10 years. This most recent report demonstrates a similar wear rate with up to 18-year follow-up.

Functional outcomes after removal of hardware in patellar fracture: are we helping our patients?

PURPOSE: Functional outcomes after Open Reduction Internal Fixation (ORIF) of the patella are variable. Common complications of patella ORIF include persistent anterior knee pain, limited range of motion and symptomatic hardware. The purpose of this study was to evaluate if removal of hardware is beneficial to symptomatic patients after patellar fracture fixation. METHODS: Patients who presented to our institution between December 2006 and November 2014 with patella fractures treated with ORIF were eligible for inclusion. Patella ORIF was performed using (1) K-wires (KW) with a tension band construct or (2) Cannulated Screws (CS) with a tension band construct. Radiological analyses included (1) AO classification and (2) measurements of prominent hardware length. Patient medical charts were reviewed for demographic and intraoperative data as well as peri/postoperative complications. All patients completed the SF-12 score, visual analog scale, Kujala score, Lysholm score and questionaries' regarding return to previous activity levels. RESULTS: Forty-seven patients met the inclusion criteria. The average time from fracture fixation to removal of hardware was 15.8 (SD ± 14.9) months. The mean follow-up was 43.1 (SD ± 27.1) months. Patella fixation was accomplished using tension band constructs with KW in 28 patients (59.5%) or with CS in 19 patients (40.5%). Patient reported quality of life and pain outcomes improved significantly after removal of hardware (p = 0.001, and p = 0.002 respectively). Functional outcome scores (Kujala and Lysholm) did not improve significantly after hardware removal in the KW or CS groups. Significantly more patients in the KW group returned to pre-injury activity (p = 0.005). CONCLUSIONS: Hardware removal after patella ORIF significantly improves patient reported pain and quality of life outcomes but not functional outcomes. Patients should be counseled regarding the expected outcome of hardware removal following patella ORIF and diabetic patients should be given special consideration before undergoing this procedure.

Does a non-stemmed constrained condylar prosthesis predispose to early failure of primary total knee arthroplasty?

PURPOSE: The use of unlinked constrained condylar components (CCK) has been extended to primary total knee arthroplasty (TKA); however, there is limited literature on its outcomes. The purpose of this retrospective cohort study was to assess clinical outcomes of one particular design of primary, non-stemmed, unlinked constrained TKA and to compare them with a control group of PS-TKA utilizing the same implant design. METHODS: The clinical and radiographic outcomes of 486-cemented, non-stemmed, primary TKA's performed by two surgeons at one institution using similar surgical algorithm, technique and prosthetic design were retrospectively reviewed. Primary TKA components were used in all knees; the only difference between groups was the type of polyethylene inserts used (CCK vs PS). Pre-operative deformity, knee society scores (KSS), range-of-motion (ROM), radiographic data and revision rates were compared. RESULTS: Both groups had comparable demographics, pre-operative coronal plane alignment, ROM and KSS. At a mean follow-up of 3.5 years, no difference was found in ROM, KSS, radiographic outcomes and revision rates. CONCLUSIONS: Cemented, primary, non-stemmed CCK-TKA offered comparable clinico-radiographic results to PS-TKA at short-term follow-up. Use of a semi-constrained insert without additional stems did not predispose to failure due to aseptic loosening with this implant design. Moreover, the rate of revision due to instability was lowered. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.

Primary vs Conversion Total Hip Arthroplasty: A Cost Analysis.

INTRODUCTION: Increasing hip fracture incidence in the United States is leading to higher occurrences of conversion total hip arthroplasty (THA) for failed surgical treatment of the hip. In spite of studies showing higher complication rates in conversion THA, the Centers for Medicare and Medicaid services currently bundles conversion and primary THA under the same diagnosis-related group. We examined the cost of treatment of conversion THA compared with primary THA. Our hypothesis is that conversion THA will have higher cost and resource use than primary THA. METHODS: Fifty-one consecutive conversion THA patients (Current Procedure Terminology code 27132) and 105 matched primary THA patients (Current Procedure Terminology code 27130) were included in this study. The natural log-transformed costs for conversion and primary THA were compared using regression analysis. Age, gender, body mass index, American Society of Anesthesiologist, Charlson comorbidity score, and smoker status were controlled in the analysis. Conversion THA subgroups formed based on etiology were compared using analysis of variance analysis. RESULTS: Conversion and primary THAs were determined to be significantly different (P<.05) and greater in the following costs: hospital operating direct cost (29.2% greater), hospital operating total cost (28.8% greater), direct hospital cost (24.7% greater), and total hospital cost (26.4% greater). CONCLUSIONS: Based on greater hospital operating direct cost, hospital operating total cost, direct hospital cost, and total hospital cost, conversion THA has significantly greater cost and resource use than primary THA. In order to prevent disincentives for treating these complex surgical patients, reclassification of conversion THA is needed, as they do not fit together with primary THA.