Comparison of acetabular shell position using patient specific instruments vs. standard surgical instruments: a randomized clinical trial.
TL;DR: Use of 3D preoperative planning along with PSIs resulted in significantly greater anteversion accuracy than traditional planning and instrumentation.
Abstract: Total hip arthroplasty (THA) survivorship relies largely upon appropriate acetabular cup placement. The purpose of this prospective randomized controlled trial was to determine whether the use of a preoperative 3D planning software in combination with patient specific instrumentation (PSI) results in improved cup placement compared with traditional techniques. Thirty-six THA patients were randomized into standard (STD) or PSI technique. Standard approach was completed using traditional techniques, while PSI cases were planned and customized surgical instruments were manufactured. Postoperative CT scans were used to compare planned to actual results. Differences found between planned and actual anteversion were -0.2° ± 6.9° (PSI) and -6.9°±8.9° (STD) (P = 0.018). Use of 3D preoperative planning along with PSIs resulted in significantly greater anteversion accuracy than traditional planning and instrumentation.
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TL;DR: The research suggests that there are several advantages to 3D-printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology.
Abstract: Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes. Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans. 227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure. 3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D-printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost–effectiveness analysis.
698 citations
TL;DR: Three-dimensional assessment of glenoid anatomy and implant templating and the use of these images at the time of surgery improve the surgeon's ability to place the glenoids implant in the desired location.
Abstract: Background: Preoperative quantitative assessment of glenoid bone loss, selection of the glenoid component, and definition of its desired location can be challenging. Placement of the glenoid component in the desired location at the time of surgery is difficult, especially with severe glenoid pathological conditions.
Methods: Forty-six patients were randomly assigned to three-dimensional computed tomographic preoperative templating with either standard instrumentation or with patient-specific instrumentation and were compared with a nonrandomized group of seventeen patients with two-dimensional imaging and standard instrumentation used as historical controls. All patients had postoperative three-dimensional computed tomographic metal artifact reduction imaging to measure and to compare implant position with the preoperative plan.
Results: Using three-dimensional imaging and templating with or without patient-specific instrumentation, there was a significant improvement achieving the desired implant position within 5° of inclination or 10° of version when compared with two-dimensional imaging and standard instrumentation.
Conclusion: Three-dimensional assessment of glenoid anatomy and implant templating and the use of these images at the time of surgery improve the surgeon’s ability to place the glenoid implant in the desired location.
Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
149 citations
TL;DR: There are numerous orthopaedic applications of threeD printing for the pelvis and acetabulum and custom-made metal 3D printed patient-specific implants and instruments are increasingly being studied for pelvic oncologic resection and reconstruction of resected defects as well as for revision hip arthroplasties with favourable results.
Abstract: There are numerous orthopaedic applications of three-dimensional (3D) printing for the pelvis and acetabulum. The authors reviewed recently published articles and summarized their experience. 3D printed anatomical models are particularly useful in pelvic and acetabular fracture surgery for planning, implant templating and for anatomical assessment of pathologies such as CAM-type femoroacetabular impingement and rare deformities. Custom-made metal 3D printed patient-specific implants and instruments are increasingly being studied for pelvic oncologic resection and reconstruction of resected defects as well as for revision hip arthroplasties with favourable results. This article also discusses cost-effectiveness considerations when preparing pelvic 3D printed models from a hospital 3D printing centre.
73 citations
TL;DR: The purpose of this review was to assess the current status of patient‐specific orthopaedic implants, to explore their future direction, and to summarize any comparative published studies that measure definitive surgical characteristics of patient-specific orthopedic implant use such as patient outcomes, biomechanical implant alignment, surgical cost, patient blood loss, or patient recovery.
Abstract: Patient-specific orthopaedic implants are emerging as a clinically promising treatment option for a growing number of conditions to better match an individual's anatomy. Patient-specific implant (PSI) technology aims to reduce overall procedural costs, minimize surgical time, and maximize patient outcomes by achieving better biomechanical implant fit. With this commercially-available technology, computed tomography or magnetic resonance images can be used in conjunction with specialized computer programs to create preoperative patient-specific surgical plans and to develop custom cutting guides from 3-D reconstructed images of patient anatomy. Surgeons can then place these temporary guides or "jigs" during the procedure, allowing them to better recreate the exact resections of the computer-generated surgical plan. Over the past decade, patient-specific implants have seen increased use in orthopaedics and they have been widely indicated in total knee arthroplasty, total hip arthroplasty, and corrective osteotomies. Patient-specific implants have also been explored for use in total shoulder arthroplasty and spinal surgery. Despite their increasing popularity, significant support for PSI use in orthopaedics has been lacking in the literature and it is currently uncertain whether the theoretical biomechanical advantages of patient-specific orthopaedic implants carry true advantages in surgical outcomes when compared to standard procedures. The purpose of this review was to assess the current status of patient-specific orthopaedic implants, to explore their future direction, and to summarize any comparative published studies that measure definitive surgical characteristics of patient-specific orthopaedic implant use such as patient outcomes, biomechanical implant alignment, surgical cost, patient blood loss, or patient recovery.
68 citations
TL;DR: This is the first study in which CT data acquired for the pre-operative planning of a custom-made revision acetabular implant have been compared with CT data on the post-operative position and the results are encouraging.
Abstract: We evaluated the accuracy with which a custom-made
acetabular component could be positioned at revision arthroplasty
of the hip in patients with a Paprosky type 3 acetabular defect. A total of 16 patients with a Paprosky type 3 defect underwent
revision surgery using a custom-made trabecular titanium implant.
There were four men and 12 women with a median age of 67 years (48
to 79). The planned inclination (INCL), anteversion (AV), rotation
and centre of rotation (COR) of the implant were compared with the post-operative
position using CT scans. A total of seven implants were malpositioned in one or more parameters:
one with respect to INCL, three with respect to AV, four with respect
to rotation and five with respect to the COR. To the best of our knowledge, this is the first study in which
CT data acquired for the pre-operative planning of a custom-made
revision acetabular implant have been compared with CT data on the
post-operative position. The results are encouraging. Cite this article: Bone Joint J 2015; 97-B:780–5.
48 citations
References
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TL;DR: It was found that anterior dislocations were associated with increased acetabular-component anteversion and there was no significant correlation between cup-orientation angle and posterior dislocation.
Abstract: In a series of 300 total hip replacements, nine (3 per cent) dislocated. Precise measurements of the orientation of the acetabular cup were made and it was found that anterior dislocations were associated with increased acetabular-component anteversion. There was no significant correlation between cup-orientation angle and posterior dislocation. The dislocation rate for cup orientation with anteversion of 15 +/- 10 degrees and lateral opening of 40 +/- 10 degrees was 1.5 per cent, while outside this "safe" range the dislocation rate was 6.1 per cent. Other factors that were documented include time after surgery (with the greatest risk in the first thirty days) and surgical history (with a greater risk in hips that have had prior surgery).
2,407 citations
"Comparison of acetabular shell posi..." refers background or methods in this paper
...Accurate acetabular cup positioning in THA decreases the risk of dislocation [12–15], impingement [16,17], and all component wear rate [18–20]....
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...Historically the recommended range of values for anteversion is 15° ± 10° and abduction is 40 ± 10° as originally described by Lewinneck [15]....
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...001) that is closer to 15°, defined by Lewwineck et al [15] as a “safe zone”....
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...However, Yoon et al [26] determined that the correct safe zone changes according to the amount of version and abduction as shown by a circle with a radius of 14° from 39° abduction and 21° anteversion, as opposed to the classic rectangle represented safe zones [13,15]....
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TL;DR: Revision TKA procedures were most commonly performed in large, urban, nonteaching hospitals in Medicare patients ages 65 to 74, and the average length of hospital stay was 5.1 days, the average total charges were $49,360, however, average LOS, average charges, and procedure frequencies varied considerably by census region, hospital type, and Procedure performed.
Abstract: Understanding the cause of failure and type of revision total knee arthroplasty (TKA) procedures performed in the United States is essential in guiding research, implant design, and clinical decision making in TKA. We assessed the causes of failure and specific types of revision TKA procedures performed in the United States using newly implemented ICD-9-CM diagnosis and procedure codes related to revision TKA data from the Nationwide Inpatient Sample (NIS) database. Clinical, demographic, and economic data were reviewed and analyzed from 60,355 revision TKA procedures performed in the United States between October 1, 2005 and December 31, 2006. The most common causes of revision TKA were infection (25.2%) and implant loosening (16.1%), and the most common type of revision TKA procedure reported was all component revision (35.2%). Revision TKA procedures were most commonly performed in large, urban, nonteaching hospitals in Medicare patients ages 65 to 74. The average length of hospital stay (LOS) for all revision TKA procedures was 5.1 days, and the average total charges were $49,360. However, average LOS, average charges, and procedure frequencies varied considerably by census region, hospital type, and procedure performed.
1,067 citations
"Comparison of acetabular shell posi..." refers background in this paper
...2 days and hospital charges of $54,553 in 2006 and is the leading cause of early revision in THA [25]....
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TL;DR: It is recommended that the operative definitions should be used to describe the orientation of prostheses and that the anatomical definitions be used for dysplastic acetabula.
Abstract: The orientation of an acetabulum or an acetabular prosthesis may be described by its inclination and anteversion. Orientation can be assessed anatomically, radiographically, and by direct observation at operation. The angles of inclination and anteversion determined by these three methods differ because they have different spatial arrangements. There are therefore three distinct definitions of inclination and anteversion. This paper analyses the differences between the definitions and provides nomograms to convert from one to another. It is recommended that the operative definitions be used to describe the orientation of prostheses and that the anatomical definitions be used for dysplastic acetabula.
951 citations
TL;DR: A technique of positioning the acetabulum by bony landmarks of the pelvis in the standing position was developed using a standing lateral preoperative roentgenogram with the X-ray tube centered over the trochanter to prevent impingement and dislocation.
Abstract: In this prospective study, a technique of positioning the acetabulum by bony landmarks of the pelvis in the standing position was developed using a standing lateral preoperative roentgenogram with the X-ray tube centered over the trochanter. Since 1984, 441 total hip arthroplasties (THAs) were done through the posterior approach with a 1.14% dislocation rate through 1988 and no dislocations in 1989. To prevent impingement and dislocation, it was determined that the safest range for cup position was 30 degrees-50 degrees abduction and 20 degrees-40 degrees flexion from the horizontal. To measure postoperative cup position, a standing true lateral roentgenogram of the operated hip allowed direct measurement of cup flexion and was reproducible within 10 degrees. No special instruments are necessary for this technique, which can be used with any THA system.
685 citations
"Comparison of acetabular shell posi..." refers background in this paper
...Designing PSIs based on a patient's unique bony morphologic features of the acetabulum from a computed tomography (CT) scan is an improvement over generic instruments by minimizing sources of error from standard surgical instruments that depend on appropriate patient positioning, pelvis orientation [8,33], exposure [34], and surgeon experience [21]....
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...However, malpositioning of the acetabular cup can result in premature implant failure requiring revision [4–10]....
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TL;DR: Steeply-inclined acetabular components, with abduction angles greater than 55 degrees, combined with a small size of component are likely to give rise to higher serum levels of cobalt and chromium ions, probably due to a greater risk of edge-loading.
Abstract: We examined the relationships between the serum levels of chromium and cobalt ions and the inclination angle of the acetabular component and the level of activity in 214 patients implanted with a metal-on-metal resurfacing hip replacement. Each patient had a single resurfacing and no other metal in their body. All serum measurements were performed at a minimum of one year after operation. The inclination of the acetabular component was considered to be steep if the abduction angle was greater than 55°.
There were significantly higher levels of metal ions in patients with steeply-inclined components (p = 0.002 for chromium, p = 0.003 for cobalt), but no correlation was found between the level of activity and the concentration of metal ions. A highly significant (p < 0.001) correlation with the arc of cover was found. Arcs of cover of less than 10 mm were correlated with a greater risk of high concentrations of serum metal ions. The arc of coverage was also related to the design of the component and to size as well as to the abduction angle of the acetabular component. Steeply-inclined acetabular components, with abduction angles greater than 55°, combined with a small size of component are likely to give rise to higher serum levels of cobalt and chromium ions. This is probably due to a greater risk of edge-loading.
536 citations
"Comparison of acetabular shell posi..." refers background in this paper
...Accurate acetabular cup positioning in THA decreases the risk of dislocation [12–15], impingement [16,17], and all component wear rate [18–20]....
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