In-hospital costs for total hip replacement performed using the supercapsular percutaneously-assisted total hip replacement surgical technique.

PURPOSE: The supercapsular percutaneously-assisted total hip (SuperPath) surgical technique for total hip replacement (THR) is a tissue-sparing approach that has been shown to improve key variables associated with the economic burden of THR (e.g., length of stay, readmissions). To date, no studies have examined the economic impact of using this technique in the United States. The objective of this study was to compare the in-hospital costs of this technique to all other THRs performed in a large hospital system in the United States. METHODS: The costing database for a large hospital system was retrospectively searched for all in-hospital costs associated with primary THRs performed between January 2013 and September 2015. Data for all SuperPath THRs (group A) were compared to that of all other THRs performed at centres within the hospital system (group B). RESULTS: Use of the SuperPath technique resulted in significant overall in-hospital cost reductions of 15.0 % (p < 0.000), including reductions in operating room costs of 17.3 % (p < 0.000), physical/occupational therapy costs of 26.8 % (p = 0.005), and pharmacy costs of 25.3 % (p < 0.000). Length of stay (1.2 vs. 2.6 days), transfusion rates (1.9 vs. 15.8 %), and 30-day readmission rates (0.4 vs. 2.9 %) were also lower in group A. CONCLUSIONS: The use of this tissue-sparing surgical technique resulted in reductions in in-hospital costs, length of stay, and readmissions when compared to all other THRs performed in a large hospital system in the United States.

In-hospital cost comparison between the standard lateral and supercapsular percutaneously-assisted total hip surgical techniques for total hip replacement.

PURPOSE: The purpose of this study was to compare the in-hospital costs associated with the tissue-sparing supercapsular percutaneously-assisted total hip (SuperPath) and traditional Lateral surgical techniques for total hip replacement (THR). METHODS: Between April 2013 and January 2014, in-hospital costs were reviewed for all THRs performed using the SuperPath technique by a single surgeon and all THRs performed using the Lateral technique by another surgeon at the same institution. RESULTS: Overall, costs were 28.4% higher in the Lateral group. This was largely attributable to increased costs associated with transfusion (+92.5%), patient rooms (+60.4%), patient food (+62.8%), narcotics (+42.5%), physical therapy (+52.5%), occupational therapy (+88.6%), and social work (+92.9%). The only costs noticeably increased for SuperPath were for imaging (+105.9%), and this was because the SuperPath surgeon performed intraoperative radiographs on all patients while the Lateral surgeon did not. CONCLUSIONS: The use of the SuperPath technique resulted in in-hospital cost reductions of over 28%, suggesting that this tissue-sparing surgical technique can be cost-effective primarily by facilitating early mobilisation and patient discharge even during a surgeon's initial experience with the approach.

Thirty-day readmission rate and discharge status following total hip arthroplasty using the supercapsular percutaneously-assisted total hip surgical technique.

PURPOSE: Recent studies have reported nearly 40% of costs associated with a 30-day episode-of-care for total joint replacements are due to post-discharge activities and 81% of those are specifically due to unplanned readmissions and discharging patients to post-acute care facilities. The purpose of this study was to determine these two key variables for total hip arthroplasty (THA) patients implanted using a tissue-sparing surgical technique and to see how these values compare to those previously reported in the United States. METHODS: The healthcare databases at three institutions were searched for primary THA patients implanted using the supercapsular percutaneously-assisted total hip (SuperPath) surgical technique between January 2013 and July 2014. Data elements included 30-day all-cause readmission rate, discharge status, transfusion rate, complications, and length of stay (LOS). RESULTS: Data were available for 479 THAs. The 30-day all-cause readmission rate, transfusion rate, and average LOS was 2.3, 3.3%, and 1.6 days, respectively. Over 91% of patients were discharged routinely home, 4.1% to skilled nursing facilities, 3.8% to home health care, and 0.6% to inpatient rehabilitation facilities. Complications included dislocation (0.8%), periprosthetic fracture (0.8%), and deep vein thrombosis (0.2 %). There were no infections reported. CONCLUSIONS: Patients implanted using this tissue-sparing technique experienced reduced 30-day all-cause readmission rates (2.3% vs. 4.2%) and more were routinely discharged home (91.5% vs. 27.3%) than have been previously reported for patients in the United States. Use of this tissue-sparing technique has the potential to significantly reduce post-discharge costs.

Long-term survivorship and complication rate comparison of a cementless modular stem and cementless fixed neck stems for primary total hip replacement.

PURPOSE: Modular necks used in total hip replacement (THR) have become an increasingly discussed topic with the recent recall of multiple modular systems, but it is anticipated that outcomes for these devices are highly design-specific. The objectives of this study were to determine if the survivorship and complication rates of a specific modular femoral stem (PROFEMUR® Z, MicroPort Orthopedics Inc., Arlington, TN, USA) were significantly lower than those of all cementless fixed neck stems in an arthroplasty registry. METHODS: The database of an arthroplasty registry was searched for all patients implanted with a specific modular stem and all those implanted with cementless fixed neck stems. Kaplan-Meier survivorship and complication rates were compared between the two groups. RESULTS: The 12-year survivorship of the modular stem (95.8%) was not significantly less than that of all cementless fixed neck stems (96.1%). There was also no difference in revision rates for dislocation, periprosthetic fractures, aseptic loosening or septic loosening between the two groups. CONCLUSIONS: The use of the specific modular stem did not adversely affect long-term component survivorship or complication rates when compared to all cementless fixed neck THRs in an arthroplasty registry.

Midterm clinical and radiographic results of the medial pivot total knee system.

PURPOSE: The ADVANCE® Medial Pivot Knee System was designed with a highly congruent medial compartment and a less conforming lateral compartment to more closely mimic the kinematics of the normal knee. The purpose of this study was to evaluate the midterm clinical and radiographic outcomes of this total knee arthroplasty (TKA) system. METHODS: Between January 1998 and December 2006, 421 primary TKAs were performed in 373 subjects using this system and a surgical technique that resects the posterior cruciate ligament. Of these, 365 TKAs in 320 subjects were available for a follow-up visit occurring at a mean of 5.3 years. Subjects were evaluated using Knee Society Scores, range of motion, and radiographic review. RESULTS: The average Knee Society clinical score was 95.5 at final follow-up, with 358 (98%) TKAs having excellent or good results. Range of motion increased from a preoperative mean of 115 to 119° at final follow-up. Component survivorship, excluding revisions for infection or trauma, was 96.6% at five years. CONCLUSIONS: This study demonstrates subjects implanted with the ADVANCE® Medial Pivot Knee System achieved satisfactory clinical and radiographic midterm outcomes.

Esophageal electric fields are predictive of atrial defibrillation thresholds.

BACKGROUND: Atrial fibrillation (AF) is a common cardiac arrhythmia characterized by disorganized cardiac electrical activity. Defibrillation electrode placement has been shown to affect the amount of energy and number of shocks required to defibrillate. The objective of this study was to investigate the relationship between esophageal electric fields (EEFs) and atrial defibrillation thresholds (ADFTs) to determine the feasibility of using EEFs during a low-strength shock to predict patient-specific defibrillation electrode placements. METHODS: AF was induced and defibrillated according to a Bayesian four-shock protocol for 12-electrode placements in six pigs. EEFs were measured during each of the four shocks of the protocol and during a 1-J shock for each electrode placement. Squared EEFs (EEF(2) s) during all shocks were compared to the ADFTs using a linear regression. RESULTS: There was a negative relationship between EEF(2) s during the 1-J shocks and ADFTs, with median R(2) values of 0.863 and 0.840 for anterior-anterior (AA) and anterior-posterior (AP) electrode placements, respectively. There was a strong, positive relationship between applied energy and EEF(2) s, with median R(2) values of at least 0.866 for all animals. The placement with the highest EEF(2) resulted in the lowest ADFT for both AA and AP placements in four of six pigs. In the other two animals, this held for one electrode set but not both. CONCLUSIONS: There was a strong negative relationship between EEF(2) s during 1-J shocks and ADFTs for both AA and AP electrode placements. These preliminary results suggest that using EEF(2) s to predict patient-specific electrode placements is feasible.

Long-term Autograft Harvest Site Pain After Ankle and Hindfoot Arthrodesis.

BACKGROUND: Pain following autograft harvest has been studied; however, published literature has typically focused on the iliac crest with follow-up limited to only a few years. It remains unknown if pain continues or improves over time. The purpose of this study was to evaluate long-term pain associated with autograft harvest to supplement hindfoot or ankle arthrodesis. METHODS: Subjects in the control arm of a previously conducted trial comparing autograft with a synthetic bone graft for hindfoot or ankle arthrodesis were invited back for a single visit at a minimum of 5 years following their initial surgery. Harvest site, fusion site, and weight-bearing pain were evaluated using a 100-point visual analog scale (VAS). Of the 130 invited subjects, 60 (46.1%) returned for assessment, 58 of whom completed pain assessments. RESULTS: At a mean follow-up of 9.0 years (range, 7.8-10.5), more than a third (36.6%) of subjects had some level of harvest site pain. Using VAS greater than 20 mm as a threshold of clinical significance, pain remained clinically significant in 5.2% of subjects. There was a significant correlation between harvest site pain and both weight-bearing and fusion site pain. There was not a significant correlation between harvest site pain and volume of graft harvested. CONCLUSION: Autograft harvest can result in chronic, clinically significant pain that can last up to 10 years. In the era of shared decision making, this information will help surgeons and patients quantify the risks of chronic pain after arthrodesis procedures that include a secondary operative incision for graft harvest. LEVEL OF EVIDENCE: Level II, prospective comparative study.

The Impact of Patient Age on Foot and Ankle Arthrodesis Supplemented with Autograft or an Autograft Alternative (rhPDGF-BB/ß-TCP).

A recent survey of orthopaedic surgeons asking about risk factors for nonunion following foot and ankle arthrodesis revealed that patient age is considered to be a relatively low risk factor, despite the potential for autologous graft quality to deteriorate with increasing age. The purpose of the current study was to evaluate the impact of patient age and graft type on fusion rates following hindfoot and ankle arthrodesis. METHODS: In this study, we analyzed data from a previously published clinical trial, comparing fusion success in 397 subjects who underwent hindfoot or ankle arthrodesis (597 joints) supplemented with either autograft or an osteoinductive autograft alternative, recombinant human platelet-derived growth factor-BB homodimer carried in beta-tricalcium phosphate (rhPDGF-BB/ß-TCP). The odds of fusion success were compared among subjects older or younger than age thresholds of 55, 60, 65, 70, and 75 years. The odds of fusion success were also compared between autograft and rhPDGF-BB/ß-TCP among subjects older than each age threshold. RESULTS: In the autograft group, the joints of subjects who were younger than the age thresholds of 60 and 65 years had >2 times the odds of successful fusion compared with those of older subjects. There was no significant difference in the odds of fusion success between the older and younger subjects at the age threshold of 55 years. In the rhPDGF-BB/ß-TCP group, there was no significant difference in the odds of successful fusion between older and younger subjects at any age threshold. When the odds of fusion success were compared between the 2 graft materials in subjects who were older than each age threshold, rhPDGF-BB/ß-TCP had approximately 2 times the odds of fusion success compared with autograft for all thresholds, except 55 years. CONCLUSIONS: The presented evidence suggests that age is an identifiable and concerning risk factor for hindfoot and ankle arthrodesis nonunion, a finding in contrast to the wider perception in the surgeon community. Notably, patients ≥60 years of age had significantly lower odds of fusion success with the use of autograft. The data reveal that use of rhPDGF-BB/ß-TCP as an alternative bone-healing adjunct may help mitigate the risk of nonunion when these procedures are performed in the elderly population. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Long-term survivorship of a medial-pivot total knee system compared with other cemented designs in an arthroplasty registry.

BACKGROUND: The Orthopaedic Data Evaluation Panel (ODEP) monitors the performance of primary total knee arthroplasty (TKA) implants against guidance provided by the National Institute for Health and Care Excellence (NICE) and issues ratings based upon survivorship data meeting or exceeding 95 % at 10-year follow-up. The objectives of the current study were to determine if the survivorship for the ADVANCE Medial-Pivot System in an arthroplasty registry exceeds this threshold and if its survivorship is significantly different than that of all other cemented bi-, tricompartmental, minimally stabilized, and fixed bearing TKAs in the same registry. METHODS: The database of an arthroplasty registry was searched for all TKAs performed with the subject system and all other cemented TKAs. The Kaplan-Meier survivorship for the subject system was compared to the NICE criteria and also that of all other cemented TKAs. Complication modes were also examined for the two groups. RESULTS: The 10-year survivorship for the included 506 TKAs using the subject system (96.3 %) exceeded the NICE guidelines of 95 % at 10 years. Survivorship also exceeded that of all other cemented TKAs (95.7 %) in the same registry, but the difference was not significantly different. CONCLUSIONS: The subject system was associated with survivorship that exceeds the NICE guidelines at 10 years and is similar to that of other cemented TKA systems. The use of this unique tibial insert design does not negatively impact component survivorship.

Patient satisfaction at 2 months following total knee replacement using a second generation medial-pivot system: follow-up of 250 consecutive cases.

BACKGROUND: Patient dissatisfaction following total knee replacement (TKR) has been reported as high as 24%. Most previous studies have focused on satisfaction for TKR overall, with few reporting satisfaction for specific implant designs. The purpose of this study was to assess patient satisfaction for TKRs performed using a second generation medial-pivot system (EVOLUTION®, MicroPort Orthopedics Inc., Arlington, TN, USA). METHODS: Of a single surgeon's first 250 consecutive TKRs performed using the subject system, 224 completed a patient satisfaction assessment, the Knee Injury and Osteoarthritis Outcome Score (KOOS), range of motion, and radiographs at 2 months follow-up. RESULTS: The overall very satisfied/satisfied rate was 94.6% at 2 months. Following the first 50 TKRs, the satisfied rate improved to 99.4% suggesting a bias towards the initial cases potentially due to learning the system and instrumentation. Overall KOOS, range of motion, and radiographic outcomes were satisfactory at final follow-up. CONCLUSIONS: In conclusion, more subjects implanted with a second generation medial-pivot system were satisfied compared to previous reports for TKR.

Use of the supercapsular percutaneously assisted total hip approach for femoral neck fractures: surgical technique and case series.

BACKGROUND: Femoral neck fractures are common injuries in the geriatric population associated with high morbidity and mortality rates. Studies have shown outcomes can be positively influenced by early postoperative mobilization. The supercapsular percutaneously assisted total hip (SuperPath) surgical technique has been shown to lead to early mobilization for osteoarthritic total hip replacement patients and as such has the potential to provide similar benefits in fracture patients. This manuscript provides a detailed description of this technique using hemiarthroplasty to treat femoral neck fractures and presents the first case series of this application. METHODS: Seventeen patients with femoral neck fractures managed with this technique at two separate institutions were reviewed. In an attempt to minimize blood loss and enhance early mobilization, hemiarthroplasty utilizing the SuperPath technique was performed. The authors noticed decreased blood loss, operative time, and postoperative narcotic usage when compared to their previous experiences using traditional techniques. CONCLUSIONS: Early mobilization following femoral neck fractures has been shown to decrease mortality and morbidity. There is little existing literature on the use of tissue-sparing surgical techniques for this application, and none details the use of the SuperPath technique for it. The described case reports suggest the technique is a viable option for bipolar hemiarthroplasty to treat femoral neck fractures. Appropriately designed future studies are needed to confirm findings and definitively compare outcomes to traditional approaches.

Esophageal electric fields are predictive of atrial cardioversion success-a finite element analysis.

BACKGROUND: Atrial fibrillation (AF) is a debilitating cardiac arrhythmia, one potential treatment of which is external cardioversion. Studies have shown external cardioversion success is affected by electrode placement and that esophageal electric fields (EEFs) during low strength shocks have the potential to be used in determining patient-specific optimal electrode placements during animal experiments. The objective of this study was to determine the relationship between EEFs and atrial defibrillation thresholds (ADFTs) during computer simulations using an anatomically realistic computer model of a human torso. METHODS: Over 600 electrode placements were simulated during which EEFs were compared to ADFTs. RESULTS: There was no single optimal electrode placement with multiple electrode placements resulting in similarly low ADFTs. There was over 40% difference in the ADFTs between the most and least optimal electrode configurations. There was no correlation between EEFs and ADFTs for all electrode placements, but a strong negative correlation when small shifts from clinically relevant electrode placements were performed. CONCLUSIONS: These results suggest a small shifts protocol from clinically relevant electrode placements has the potential to increase the probability of successful cardioversion on the first shock and reduce the cumulative number of shocks and energy to which patients are exposed.

Supercapsular percutaneously-assisted total hip arthroplasty: radiographic outcomes and surgical technique.

BACKGROUND: The supercapsular percutaneously-assisted total hip (SuperPATH(®)) approach for total hip arthroplasty (THA) was developed to promote early mobilization and greater range of motion, physiologic gait kinematics and improved pain control. The superpath approach is a hybrid of the Superior Capsulotomy (SuperCap(®)) approach and the percutaneously assisted total hip (PATH(®)) technique. METHODS: Postoperative radiographs of 66 consecutive patients from the first 100 patients who underwent the SuperPATH approach were analysed by an independent third party for component position and seating, femoral offset and leg length. A detailed description of preoperative and postoperative preparation, soft tissue dissection, preparation of the femoral canal and acetabulum, and implant positioning is also provided with figures to illustrate. RESULTS: All components in this case series were well seated and position deemed optimal. Leg lengths were measured to within 5 mm of the contralateral side and mean acetabular abduction angle was 40.13° (SD 6.30°). CONCLUSIONS: Through preservation of the external rotators, hip capsule, and abductor integrity, the SuperPATH approach for THA maximally preserves the surrounding soft tissue envelope. Implant position was optimal within the 'learning curve' of the first 100 cases for described THA safe zones. Long term outcome data for the SuperPATH approach are being collected as part of an ongoing study to compare to favourable short and mid-term results.

Early surgical and functional outcomes comparison of the supercapsular percutaneously-assisted total hip and traditional posterior surgical techniques for total hip arthroplasty: protocol for a randomized, controlled study.

BACKGROUND: Total hip arthroplasty (THA) is one of the most commonly performed and successful orthopaedic surgeries. While the long-term success of THA is well documented, there is still significant room for improving patient speed of recovery and return to activities. The surgical technique used during THA has the potential to affect these early outcomes. METHODS: The described design is a single center, prospective, randomized, controlled study. Subjects will be randomized to receive THA using either the supercapsular percutaneously-assisted total hip (SuperPath) or traditional posterior surgical techniques. Subjects will be evaluated using Timed Up and Go (TUG), Timed Stair Climb (TSC), Hip Dysfunction and Osteoarthritis Outcome Score (HOOS), and Visual Analog Scale (VAS) for pain level estimation preoperatively, during the hospital stay, and at 2, 6 weeks, and 100 days post-discharge. Other endpoints to be evaluated include: length of stay (LOS); discharge status; transfusion rates; readmission rates; complication rates; operative time; date returned to work; and acetabular component anteversion and inclination angles. DISCUSSION: The described study will determine the effect of a tissue-sparing surgical technique on short term subject recovery following THA in comparison to the most commonly used technique in clinical practice.

An esophageal probe for measuring three-dimensional electric fields during external cardiac defibrillation.

External defibrillation is a common treatment for the cardiac arrhythmia atrial fibrillation. Electrode placement has been shown to affect defibrillation efficacy and required energy levels. We suggest investigating the relationship between esophageal electric fields (EEFs) and atrial defibrillation thresholds to determine the feasibility of creating patient-specific electrode placements using EEFs. This study presents the design and implementation of an esophageal probe (EP) that accurately measures three-dimensional electric fields. The root-mean-square error of the EP was 1.69% as determined by measurements performed in an electrolytic tank. The EP also performed well during in vivo testing in a pig. There was a strong positive relationship between EEF(2)s and applied energy during defibrillation strength shocks. The EEF measurements were also repeatable, with less than 4.24% difference between repeated shocks. This is the first description of a probe designed specifically for measuring electric fields in the esophagus.

Thermal phantom of the intervertebral disc for evaluating intradiscal electrothermal therapies.

STUDY DESIGN: a silicone material was evaluated as an intervertebral disc thermal phantom. Temperature mapping was performed during the intradiscal electrothermal therapy (IDET) procedure and compared with results from the cadaver studies. OBJECTIVE: to determine whether a silicone material can be used as an intervertebral disc thermal phantom for evaluating thermal distributions of intradiscal electrothermal therapies and for reducing the need for cadaver and animal studies. SUMMARY OF BACKGROUND DATA: studies mapping thermal profiles of intradiscal heating therapies have been performed in cadavers and animal models. These studies are expensive, require special facilities and institutional reviews, and are susceptible to intercadaver and/or interanimal variation. A search of published data yielded no proposed thermal phantoms of the intervertebral disc. METHODS.: The thermal conductivity of a silicone material was measured and compared with that of an intervertebral disc. Thermal distributions were mapped in the material during the IDET procedure and compared with the distributions seen in cadaver studies. Logarithmic regression was performed to predict temperatures at certain distances from the IDET catheter. Mapping and regression were also performed for a decompression catheter. RESULTS: the thermal conductivity of the silicone material, 0.587 W/m · °C, was similar to that previously reported for the intervertebral disc, 0.595 W/m · °C. Thermal distributions during the IDET procedure were comparable with those seen in previous cadaver studies. Logarithmic regression analysis predicted temperatures greater than 42°C and 60°C at distances of 14.10 and 2.31 mm, respectively, for the IDET catheter. These distances were 12.98 and 3.30 mm, respectively, for the decompression catheter. CONCLUSION: the silicone material has a thermal conductivity similar to that of intervertebral disc. Temperature distributions in the material during IDET treatment are similar to that seen in cadaver studies. The material provides an alternative to cadaver and animal studies when determining thermal distributions of intradiscal electrothermal therapies.

Esophageal electric fields are correlated to atrial defibrillation thresholds: towards patient-specific optimization of external atrial defibrillation.

Studies have investigated the effect of defibrillator paddle position on the efficacy of external electrocardioversion of atrial fibrillation, without agreeing upon an optimal placement. We wish to investigate using esophageal electric fields (EEFs) to predict atrial defibrillation thresholds (ADFTs) on a patient-specific basis. We propose to (1) investigate the relationship between EEFs and ADFTs using computer simulations, (2) develop an esophageal probe that can accurately measure three-dimensional electric fields and (3) investigate the relationship between EEFs and ADFTs values in-vivo. Sixteen anterior-anterior and eleven anterior-posterior placements were simulated yielding a negative relationship between EEFs and ADFTs (R2=0.91 and 0.93, respectively). An esophageal probe was developed that accurately measures EEFs. Animal studies showed a negative relationship between EEFs and ADFTs. This data suggests using EEFs to predict ADFTs on a patient-specific basis is plausible.