Mathys Ltd., Switzerland supports the funding of the clinical and radiological multicenter study.

The presented research has been performed in compliance with all institutional, national, and international guidelines for human welfare. Institutional review board approval has been obtained.
<ol>
	<li>Position the patient in supine position on a standard operating table with two separate leg supports. Allow the ipsilateral legs to remain mobile.</li>
	<li>Apply standard sterile coverage suitable for the antero-lateral approach in supine position.</li>
	<li>Slightly flex the ipsilateral side using a knee roll. In addition, hyperextend the contralateral side about 15&#176; for the femoral preparation.</li>
	<li>Locate the tip of the greater trochanter as well as the anterior superior iliac spine by palpation serving as orientation.</li>
	<li>Perform the skin- incision using a surgical knife (6 - 12 cm, depending on the patient&#39;s anatomy) centered on the tip of the greater trochanter aiming at the anterior superior iliac spine above the intermuscular septum between the gluteus medius and the tensor fasciae latae.</li>
	<li>After incision of subcutaneous fat, use two skin retractors anteriorly and posteriorly. Open the fascia without causing damage to the tensor fasciae latae.</li>
	<li>Do a blunt dissection using your index finger, pushing the gluteal muscles posteriorly without damage.</li>
	<li>Expose the joint capsule using three retractors.</li>
	<li>Perform the capsulectomy alongside the femoral neck. 
	NOTE: No sharp dissection of any muscle, in particular the gluteal muscles, is needed.</li>
	<li>After removal of the anterior joint capsule, expose the femoral neck in order to perform the osteotomy by placing the two facing curved retractors intracapsular around the femoral neck (Figure 1). 
	NOTE: The most important step in the implantation of a calcar-guided short stem is the choice of the individual level of the osteotomy. This way, stem-positioning can be done individually in a great variety, resulting in a large bandwidth of CCD-angles to be reconstructed (Figure 2; Figure 3). Consequently, a preoperative planning is mandatory to display the exact level (Figure 4: red line (OL: level of osteotomy)).</li>
	<li>For the surgeon&#39;s orientation, in order to determine the level of the osteotomy, perform a palpation of the lesser trochanter and the fossa piriformis. If a valgus position is desired according to the preexisting anatomy, perform the osteotomy distally by resecting most of the femoral neck (Figure 5a). In order to align the stem in a varus position, resect proximally, retaining most of the femoral neck, according to the preoperative planning (Figure 5c). Femoral offset and leg length can thus be maintained precisely (Figure 5).</li>
	<li>Perform the osteotomy (Figure 1) in slight external rotation of the ipsilateral leg according to the preoperative planning using a long stiff bladed oscillating saw.</li>
	<li>Remove the femoral head from the acetabulum using the femoral head extractor. To protect the gluteus medius, place a &#34;Langenbeck&#34;-retractor medially and pull proximally.</li>
	<li>During acetabular preparation, insert a &#34;Steinmann&#34;-pin in the proximal end of the acetabulum to protect the gluteal muscles.</li>
	<li>Expose the acetabulum using two extractors.</li>
	<li>Implant the acetabular component according to the preoperative planning and depending on the patient&#39;s individual anatomy.</li>
	<li>For femoral preparation, first remove the knee roll and hyperextend the contralateral leg about 15&#176;. Now perform a 90&#176; external rotation and a maximum of 90&#176; flexion of the knee joint. Have the assistant hold the subject&#39;s leg at maximal adduction (about 40&#176;).</li>
	<li>Position two retractors on the medial side of the proximal femoral neck and proximally at the posterior (medial) cortical end of the femoral neck. Avoid contact to the greater trochanter, to minimize the risk of possible damage to the bone and the muscle insertions.</li>
	<li>Apply the &#34;round-the-corner&#34; technique to open the proximal femur alongside the calcar with the curved opening awl. 
	NOTE: Posterior structures such as the greater trochanter or the gluteal muscles are not affected.</li>
	<li>Drive in gently specially curved, implant-shaped rasps in ascending sizes using a hammer in order to prepare the proximal femur and the femoral canal until cortical contact and a stable fit and fill are reached. Note that a double offset minimally-invasive rasp handle is available. Perform the insertion guided by the calcar in the &#34;round-the-corner&#34; technique (Figure 6).</li>
	<li>Choose one of the two available trial cones with different offset versions (standard and lateral offset) according to the preoperative planning.</li>
	<li>Assess an intraoperative fluoroscopy using a digital image intensifier after inserting a trial head and performing a trial reduction to compare the positioning of the rasp (trial implant) to the preoperative planning (Figure 7). Perform an anterior-posterior radiograph. To screen the second plane, also perform an axial view radiograph. Perform adjustments, if necessary. 
	NOTE: Reaching cortical contact is essential regarding the risk of postoperative subsidence. Avoid undersizing! (Figure 8)</li>
	<li>Remove the trial implants and insert the definitive implant containing the chosen offset version using the special implant impactor. Note that the original stem aligns itself exactly like the trial rasp (Figure 9).</li>
	<li>After the final reduction by applying axial tension combined with internal rotation of the leg, complete the procedure by standard wound closure.</li>
	<li>In most cases, allow full weight-bearing after surgery using 2 crutches under physiotherapeutic surveillance starting 4 h after the operation. 
	NOTE: In heavy patients, primary stability might be impaired, thus, weight bearing protocol must be adjusted accordingly.</li>
	<li>Provide analgesics according to the intensity of pain recorded, non-steroidal-anti-inflammatory-drugs (NSAID) to prevent heterotopic ossification, and venous thromboembolic prophylaxis.</li>
</ol>

<ol>
	<li>Jerosch, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Kurzschaftendoprothesen an der H&#252;fte. , (2017).</li><li>Kutzner, K. P., Donner, S., Schneider, M., Pfeil, J., Rehbein, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-stage+bilateral+implantation+of+a+calcar-guided+short-stem+in+total+hip+arthroplasty.">One-stage bilateral implantation of a calcar-guided short-stem in total hip arthroplasty.</a> Oper Orthop Traumatol. , (2017).</li><li>Anderl, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2-Jahres-Ergebnisse+mit+dem+Optimys-Kurzschaft+über+den+direkten+anterolateralen+Zugang.+JATROS.">2-Jahres-Ergebnisse mit dem Optimys-Kurzschaft über den direkten anterolateralen Zugang. JATROS.</a> Orthop&#228;die &amp; Rheumatologie 05/2015. 05, (2015).</li><li>Kutzner, K. P., Kovacevic, M. P., Roeder, C., Rehbein, P., Pfeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstruction+of+femoro-acetabular+offsets+using+a+short-stem.">Reconstruction of femoro-acetabular offsets using a short-stem.</a> Int Orthop. 39 (7), 1269-1275 (2015).</li><li>Matsushita, A., Nakashima, Y., Jingushi, S., Yamamoto, T., Kuraoka, A., Iwamoto, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+the+Femoral+Offset+and+the+Head+Size+on+the+Safe+Range+of+Motion+in+Total+Hip+Arthroplasty.">Effects of the Femoral Offset and the Head Size on the Safe Range of Motion in Total Hip Arthroplasty.</a> J Arthroplasty. 24, 646-651 (2009).</li><li>Asayama, I., Chamnongkich, S., Simpson, K. J., Kinsey, T. L., Mahoney, O. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstructed+hip+joint+position+and+abductor+muscle+strength+after+total+hip+arthroplasty.">Reconstructed hip joint position and abductor muscle strength after total hip arthroplasty.</a> J Arthroplasty. 20, 414-420 (2005).</li><li>Kutzner, K. P., Pfeil, J., Kovacevic, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preoperative+digital+planning+versus+postoperative+outcomes+in+total+hip+arthroplasty+using+a+calcar-guided+short+stem:+frequent+valgization+can+be+avoided.">Preoperative digital planning versus postoperative outcomes in total hip arthroplasty using a calcar-guided short stem: frequent valgization can be avoided.</a> Eur J Orthop Surg Traumatol. 27 (5), 643-651 (2017).</li><li>H&#246;hle, P., Schr&#246;der, S. M., Pfeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+between+preoperative+digital+planning+and+postoperative+outcomes+in+197+hip+endoprosthesis+cases+using+short+stem+prostheses.">Comparison between preoperative digital planning and postoperative outcomes in 197 hip endoprosthesis cases using short stem prostheses.</a> Clin Biomech. 30 (1), 46-52 (2015).</li><li>Kutzner, K. P., Freitag, T., Donner, S., Kovacevic, M. P., Bieger, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outcome+of+extensive+varus+and+valgus+stem+alignment+in+short-stem+THA:+clinical+and+radiological+analysis+using+EBRA-FCA.">Outcome of extensive varus and valgus stem alignment in short-stem THA: clinical and radiological analysis using EBRA-FCA.</a> Arch Orthop Trauma Surg. (3), 431-439 (2016).</li><li>Kutzner, K. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incidence+of+heterotopic+ossification+in+minimally+invasive+short-stem+THA+using+the+modified+anterolateral+approach.">Incidence of heterotopic ossification in minimally invasive short-stem THA using the modified anterolateral approach.</a> Hip Int. , (2017).</li><li>Kutzner, K. P., Kovacevic, M. P., Roeder, C., Rehbein, P., Pfeil, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstruction+of+femoro-acetabular+offsets+using+a+short-stem.">Reconstruction of femoro-acetabular offsets using a short-stem.</a> Int Orthop. , (2014).</li><li>Kutzner, K. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-stage+bilateral+versus+unilateral+short-stem+total+hip+arthroplasty:+comparison+of+migration+patterns+using+"Ein-Bild-Roentgen-Analysis+Femoral-Component-Analysis".">One-stage bilateral versus unilateral short-stem total hip arthroplasty: comparison of migration patterns using "Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis".</a> Int Orthop. 41 (1), 61-66 (2017).</li><li>Kutzner, K. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiographic+alterations+in+short-stem+total+hip+arthroplasty:+a+2-year+follow-up+study+of+216+cases.">Radiographic alterations in short-stem total hip arthroplasty: a 2-year follow-up study of 216 cases.</a> Hip Int. 26 (3), 278-283 (2016).</li><li>Kutzner, K. P., Kovacevic, M. P., Freitag, T., Fuchs, A., Reichel, H., Bieger, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+patient-related+characteristics+on+early+migration+in+calcar-guided+short-stem+total+hip+arthroplasty:+a+2-year+migration+analysis+using+EBRA-FCA.">Influence of patient-related characteristics on early migration in calcar-guided short-stem total hip arthroplasty: a 2-year migration analysis using EBRA-FCA.</a> J Orthop Surg Res. 11 (1), 29 (2016).</li><li>Kovacevic, M. P., Pfeil, J., Kutzner, K. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implantation+of+a+new+short+stem+in+simultaneous+bilateral+hip+arthroplasty+-+a+prospective+study+on+clinical+and+radiographic+data+of+54+consecutive+patients.">Implantation of a new short stem in simultaneous bilateral hip arthroplasty - a prospective study on clinical and radiographic data of 54 consecutive patients.</a> OUP. 10, 456-461 (2014).</li><li>Hochreiter, J., Hejkrlik, W., Emmanuel, K., Hitzl, W., Ortmaier, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+loss+and+transfusion+rate+in+short+stem+hip+arthroplasty.+A+comparative+study.">Blood loss and transfusion rate in short stem hip arthroplasty. A comparative study.</a> Int Orthop. , 1-7 (2016).</li><li>Bieger, R., Ignatius, A., Decking, R., Claes, L., Reichel, H., D&#252;rselen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+stability+and+strain+distribution+of+cementless+hip+stems+as+a+function+of+implant+design.">Primary stability and strain distribution of cementless hip stems as a function of implant design.</a> Clin Biomech. 27 (2), 158-164 (2012).</li><li>Loweg, L., Kutzner, K. P., Rehbein, P., Stephan, H., Pfeil, J., Schneider, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wertigkeit+der+intraoperativen+R&#246;ntgenkontrolle+in+der+prim&#228;ren+H&#252;ftendoprothetik.">Wertigkeit der intraoperativen R&#246;ntgenkontrolle in der prim&#228;ren H&#252;ftendoprothetik.</a> OUP. 5 (6), 334-338 (2016).</li></ol>

J. Pfeil is a medical advisor for Mathys Ltd., Switzerland.

Calcar-guided short stems provide many advantages in modern THA compared to conventional straight-stem designs in short-term follow-up. However, only a few results are published regarding mid- and long-term follow-up.
Due to the short and curved design of calcar-guided short stems, the soft-tissue sparing implantation appears to be technically easy. However, the individualized implantation technique requires distinct knowledge about the characteristics of different varus- and valgus positioning. A severe learning curve must be taken into account.
Modifications and Troubleshooting:
Given the individualized positioning of calcar-guided short stems, the preparation of a preoperative planning is absolutely mandatory8 (Figure 4). Besides the detection of the correct implant sizes, especially the alignment of the stem along with the desired level of the osteotomy can be determined. Intraoperatively, using the inserted trial rasp, after reduction of the hip a comparison to the preoperative planning can be done by performing intraoperative fluoroscopy19 (Figure 7). The lateral shoulder of the implant serves as orientation regarding leg length.
Limitations of the Technique:
Investigations suggest a broad bandwidth of different hip anatomies to be adequately reconstructed using calcar-guided short stems5,8 (Figure 2; Figure 3). Previous studies have investigated the outcome of extensive varus- and valgus stem alignment10. After 2 years no revision surgery was needed and the rate of radiographic alterations indicating abnormal stress distribution in total was low. However, especially for valgus-hips a pronounced initial subsidence was observed10.
Particularly for young and unexperienced surgeons the presented technique may come with undesired pitfalls.
Significance with Respect to Existing Methods:
The implantation technique of calcar-guided short stems with individualized neck resection differs from conventional straight stems and certain neck resecting and neck retaining short-stems. Conventional straight stems provide diaphyseal anchorage along with a mostly standardized level of osteotomy of the femoral neck. The preexisting hip anatomy can only be reconstructed by using different offset-versions of the implant5. In extensive varus anatomies for example, this often cannot be achieved properly (Figure 10). Valgization has been found to be the limiting factor in the successful reconstruction of hip geometry also in many previous short-stem designs, causing reduced offset and increased leg length9.
Critical Steps Within the Protocol:
The most critical step consists of choosing the right level of the osteotomy. Furthermore, in order to intraoperatively correctly realize the preoperative planning, a verification using fluoroscopy is needed.
Given a shortening of stem length in calcar-guided short-stem THA, primary stability potentially causes concerns18. The predominant type of fixation is metaphyseal anchoring, based on the fit-and-fill principle. However, due to the option of individualized positioning of these stem-designs, the type of anchoring might differ distinctly. In varus alignment three-point anchoring is common with cortical contact to the lateral cortex of the partially resected neck, the medial calcar, and the lateral cortex at the tip of the stem. However, depending on positioning and sizing, especially in extensive valgus alignment, pronounced diaphyseal anchorage is possible10. In those cases, a securely achieved cortical contact to the distal lateral cortex, as well as to the distal medial cortex is crucial. In valgus position a missing cortical contact of the tip has been frequently observed in the early collective including the learning curve, particularly in cases of undersizing. Therefore, surgeons should take into account, that particularly in valgus hips, undersizing accompanied with a lack of contact to the lateral cortex, might cause initial instability and subsequent implant micromovement10. The usage of intraoperative fluoroscopy to identify undersizing of the stem is therefore highly recommended19.
The present description of the technique, regarding reconstruction of offset, refers only to a two-dimensional analysis. However, given a partially retained femoral neck, short stems will position themselves almost automatically along the anteversion and anterior tilt of the preexisting proximal femoral bone. In particular in varus-hips, this leads to distinct anterior tilting in the axial plane with the stem&#39;s tip being positioned anteriorly (Figure 11). Thus, anterior offset can be reconstructed as well. Further monitoring of this new generation of short stems and the implantation technique in mid- and long-term follow-up is mandatory.

Modern calcar-guided short-stems have been increasingly used in THA in recent years1. New calcar-guided, metaphyseal anchoring short-stems are emerging that focus on sparing muscles, soft-tissue, and bone2,3, thus allowing minimally-invasive (MIS) techniques and approaches to be successfully applied4.
The possible benefits of calcar-guided short-stem THA can be accomplished through a special implantation technique, which differs from conventional techniques used with traditional straight-stem designs. The most important aspect, in this regard, is the anatomical curvature, which has been adapted from the calcar. The positioning of the stem follows the individual anatomy alongside the calcar curve, and permits individualized implantation5. Applying the so called &#34;round-the-corner&#34; technique, the greater trochanter region and most importantly the gluteal muscles, can be spared almost completely2.
Modern THA is largely dependent on the successful preservation of hip geometry. The accurate reconstruction of the hip joint anatomy is crucial for the clinical outcome. The femoro-acetabular offset has increasingly come into focus5. Reduced offset might lead to gluteal insufficiency along with instability of the hip joint and increased risk of dislocation6,7. On the other hand, a severe increase in offset can cause trochanteric bursitis. Given these findings, it appears that undesired changes of offset have great clinical relevance.
Reconstruction of the femoral offset is highly dependent on the ability to reproduce different CCD-angles8. However, valgization has been found to be the limiting factor in the successful reconstruction of hip geometry in many stem designs, causing reduced offset and increased leg length9. The reconstruction of different CCD-angles, in this regard, seems to be the key to accomplish the retainment of the hip anatomy.
In calcar-guided short-stem THA, stem alignment can be individualized, which supports the successful reconstruction of the femoral offset8. Guiding the stem alongside the calcar, the positioning of the stem in the proximal femur is dependent on the resection level of the femoral neck. Given a preexisting varus anatomy, a high resection also results in a varus position of the implant, maintaining a large femoral offset. On the other hand, given a preexisting valgus anatomy, a low resection results in a valgus position, causing a small femoral offset10 (Figure 1; Figure 2).
Consequently, the presented individualized implantation technique allows a broad reconstruction of CCD-angles and thus enables a precise preservation of hip geometry. The presented technique differs from conventional total hip arthroplasty and potentially includes a severe learning curve.

<table border="0" cellpadding="0" cellspacing="0" width="677">
	<tbody>
		<tr height="40">
			<td height="40" style="height:30.0pt;width:149pt" width="198">optimys short stem</td>
			<td style="width:173pt" width="230">Mathys Ltd., Switzerland</td>
			<td style="width:90pt" width="120"></td>
			<td style="width:97pt" width="129">Implant</td>
		</tr>
	</tbody>
</table>

individualized stem-positioning in calcar-guided short-stem total hip arthroplasty

Bone- and soft-tissue sparing short stems are increasingly used in total hip arthroplasty (THA). However, there are a large variety of models of short stems, differing in design and function. Calcar-guided short stems provide an anatomical curvature in the medial calcar region, thus, positioning is done individually alongside the calcar in the "round-the-corner" technique. Depending on the level of the neck's osteotomy, stems can be aligned individually in a large bandwidth of varus- and valgus anatomies. This differs from conventional total hip arthroplasty and potentially includes a severe learning curve. Given that a great variety of caput-collum-diaphyseal (CCD)-angles can be retained, the reconstruction of femoro-acetabular offsets can be achieved precisely. However, particularly extensive varus- and valgus positioning has raised concerns in regard to stability and bone remodeling. The purpose of the present manuscript is to showcase the implantation technique in calcar-guided short-stem THA and to summarize short-term clinical and radiological results.

Several short-term results of the investigated short-stem have previously been published, mostly arising from an ongoing observational study at the author&#39;s institution2,8,11,12,13,14,15,16. Using the presented technique, the reconstruction of different femoro-acetabular offsets can be accomplished precisely5. Particularly the ability to preserve the preexisting CCD-angle allows physiological hip geometry retainment8. After two years, only a few radiological alterations, such as stress-shielding and cortical hypertrophy were obvious14. The minimally-invasive technique caused low incidences of heterotopic ossifications11. Therefore, the blood loss and transfusion rate remains at a lower rate compared to the implantation technique using conventional straight stems17.
Excellent clinical results have led to successful usage of this technique in one-stage bilateral short-stem THA2. Ein-Bild-Roentgen-Analyses &#34;femoral component analysis&#34; (EBRA-FCA) of the presented implant have shown an increased initial axial subsidence especially in heavy and active male patients, given full weight bearing postoperatively, however, without any clinical consequences in the early stage13,15. Particularly stems that have been aligned in the valgus position result in increased early subsidence, but undersizing and insufficient cortical contact laterally, could be identified as the main cause18.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56905/56905fig1.jpg" /> 
Figure 1: Osteotomy of the femoral neck. The osteotomy is done according to the preoperative planning. The level of the osteotomy is determined by palpating the lesser trochanter and the tip of the greater trochanter, serving as a reference. From2,4.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56905/56905fig2.jpg" /> 
Figure 2: Valgus positioning. The stem is aligned in valgus position following a low osteotomy.
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56905/56905fig3.jpg" /> 
Figure 3: Varus positioning. The stem is aligned in varus position following a high osteotomy.
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56905/56905fig4.jpg" /> 
Figure 4: Preoperative planning. Blue: Template of the calcar-guided short stem; red: template of the cement-less cup. The level of osteotomy is determined according to the preoperative planning (OL). Intraoperatively, also the height of the lateral shoulder of the implant serves as orientation (SH). Most importantly the stem has to be upsized until cortical contact laterally is reached (CC).
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56905/56905fig5.jpg" /> 
Figure 5: Individualized level of osteotomy and stem alignment. The positioning of the stem in the proximal femur is dependent on the resection level of the femoral neck. Given a varus anatomy, a high resection also results in a varus position of the implant, maintaining a large femoral offset (c). On the other hand, given a valgus anatomy, a low resection results in a valgus position, causing a small femoral offset (a).10,12 From Kutzner et al.2 <a href="https://cloudflare.jove.com/files/ftp_upload/56905/56905fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56905/56905fig6.jpg" /> 
Figure 6: Round-the-corner technique. The insertion is done alongside the medial calcar, not affecting lateral structures. Especially the greater trochanter and the gluteal muscles can be spared. From Kutzner et al.2 <a href="https://cloudflare.jove.com/files/ftp_upload/56905/56905fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56905/56905fig7.jpg" /> 
Figure 7: Intraoperative fluoroscopy. After completing trial reduction, the assessment of intraoperative radiography in two planes using a digital image intensifier should be considered mandatory to be able to compare the positioning of the rasp (trial implant) to the preoperative planning. Potential adjustments can be performed subsequently. From Kutzner et al.2 <a href="https://cloudflare.jove.com/files/ftp_upload/56905/56905fig7large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/56905/56905fig8v2.jpg" /> 
Figure 8: Example of undersizing.&#160;Insufficient cortical contact&#160;and undersizing (a)&#160;results in subsequent subsidence in the 2 year follow-up (b). <a href="https://cloudflare.jove.com/files/ftp_upload/56905/56905fig8v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/56905/56905fig9v2.jpg" /> 
Figure 9: Implantation of the original calcar-guided short stem. The original implant positions itself exactly like the trial rasp. From Kutzner et al.2
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/56905/56905fig10v2.jpg" /> 
Figure 10: Examples of offset-reconstruction in varus-hips with different stem types. (a, b) Offset-reconstruction cannot be achieved due to diaphyseal anchorage and design of conventional straight stems. (c) Varus-alignment with a calcar-guided short stem accomplishes an exact reconstruction of offset. <a href="https://cloudflare.jove.com/files/ftp_upload/56905/56905fig10v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/56905/56905fig11.jpg" /> 
Figure 11: Example of the intraoperative fluoroscopy in two planes. (a) a.p. view; (b) axial view. Short stems will position themselves almost automatically along the anteversion and anterior tilt of the preexisting proximal femoral bone. Thus, anterior offset can also be restored. <a href="https://cloudflare.jove.com/files/ftp_upload/56905/56905fig11large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty at JoVE.com

Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty

This protocol describes the round-the-corner technique and the individualized stem-positioning of calcar-guided short stems alongside the medial calcar, depending on the level of the osteotomy. This differs from conventional total hip arthroplasty and includes a learning curve.

Bone- and soft-tissue sparing short stems are increasingly used in total hip arthroplasty (THA). However, there are a large variety of models of short ...

individualized-stem-positioning-calcar-guided-short-stem-total-hip

Research

JoVE Journal

Medicine

11.6K Views.  St. Josefs Hospital Wiesbaden. This protocol describes the round-the-corner technique and the individualized stem-positioning of calcar-guided short stems alongside the medial calcar, depending on the level of the osteotomy. This differs from conventional total hip arthroplasty and includes a learning curve.

Video: Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty

Reverse Total Shoulder Arthroplasty

Reverse total shoulder arthroplasty was initially approved for use in rotator cuff arthropathy and well as chronic pseudoparalysis without arthritis in patients who were not appropriate for tendon transfer reconstructions. Traditional surgical options for these patients were limited and functional results were sub-optimal and at times catastrophic. The use of reverse shoulder arthroplasty has been found to effectively restore these patients function and relieve symptoms associated with their disease. The procedure can be done through two approaches, the deltopectoral or the superolateral. Complication rates associated with the use of the prosthesis have ranged from 8-60% with more recent reports trending lower as experienced is gained. Salvage options for a failed reverse shoulder prosthesis are limited and often have significant associated disability. Indications for the use of this prosthesis continue to be evaluated including its use for revision arthroplasty, proximal humeral fracture and tumor. Careful patient selection is essential because of the significant risks associated with the procedure.

Reverse total shoulder arthroplasty is indicated for the treatment of conditions that cannot be treated with conventional arthroplasty or other procedures. These primarily include degenerative and incapacitating conditions with irreparable rotator cuff and loss of the normal biomechanical coupling of the shoulder.

Reverse total shoulder arthroplasty was initially approved for use in rotator cuff arthropathy and well as chronic pseudoparalysis without arthritis in ...

Implantation of the Syncardia Total Artificial Heart

With advances in technology, the use of mechanical circulatory support devices for end stage heart failure has rapidly increased. The vast majority of such patients are generally well served by left ventricular assist devices (LVADs). However, a subset of patients with late stage biventricular failure or other significant anatomic lesions are not adequately treated by isolated left ventricular mechanical support. Examples of concomitant cardiac pathology that may be better treated by resection and TAH replacement includes: post infarction ventricular septal defect,&#160;aortic root aneurysm / dissection, cardiac allograft failure, massive ventricular thrombus, refractory malignant arrhythmias (independent of filling pressures), hypertrophic / restrictive cardiomyopathy, and complex congenital heart disease. Patients often present with cardiogenic shock and multi system organ dysfunction. Excision of both ventricles and orthotopic replacement with a total artificial heart (TAH) is an effective, albeit extreme, therapy for rapid restoration of blood flow and resuscitation. Perioperative management is focused on end organ resuscitation and physical rehabilitation. In addition to the usual concerns of infection, bleeding, and thromboembolism common to all mechanically supported patients, TAH patients face unique risks with regard to renal failure and anemia. Supplementation of the abrupt decrease in brain natriuretic peptide following ventriculectomy appears to have protective renal effects. Anemia following TAH implantation can be profound and persistent. Nonetheless, the anemia is generally well tolerated and transfusion are limited to avoid HLA sensitization. Until recently, TAH patients were confined as inpatients tethered to a 500 lb pneumatic console driver. Recent introduction of a backpack sized portable driver (currently under clinical trial) has enabled patients to be discharged home and even return to work. Despite the profound presentation of these sick patients, there is a 79-87% success in bridge to transplantation.

The purpose of this manuscript is to briefly review indications, management, and outcomes for the total artificial heart. Video operative techniques for device implantation are presented.

With advances in technology, the use of mechanical circulatory support devices for end stage heart failure has rapidly increased. The vast majority of ...

Using Continuous Data Tracking Technology to Study Exercise Adherence in Pulmonary Rehabilitation

Pulmonary rehabilitation (PR) is an important component in the management of respiratory diseases. The effectiveness of PR is dependent upon adherence to exercise training recommendations. The study of exercise adherence is thus a key step towards the optimization of PR programs. To date, mostly indirect measures, such as rates of participation, completion, and attendance, have been used to determine adherence to PR. The purpose of the present protocol is to describe how continuous data tracking technology can be used to measure adherence to a prescribed aerobic training intensity on a second-by-second basis.
In our investigations, adherence has been defined as the percent time spent within a specified target heart rate range. As such, using a combination of hardware and software, heart rate is measured, tracked, and recorded during cycling second-by-second for each participant, for each exercise session. Using statistical software, the data is subsequently extracted and analyzed. The same protocol can be applied to determine adherence to other measures of exercise intensity, such as time spent at a specified wattage, level, or speed on the cycle ergometer. Furthermore, the hardware and software is also available to measure adherence to other modes of training, such as the treadmill, elliptical, stepper, and arm ergometer. The present protocol, therefore, has a vast applicability to directly measure adherence to aerobic exercise.

Pulmonary rehabilitation is widely recognized in the management of respiratory diseases. A key component to successful pulmonary rehabilitation is adherence to the recommended exercise training. The purpose of the present protocol is to describe how continuous data tracking technology can be used to precisely measure adherence to a prescribed aerobic training intensity.

Pulmonary rehabilitation (PR) is an important component in the management of respiratory diseases. The effectiveness of PR is dependent upon adherence to ...

Implantation of Total Artificial Heart in Congenital Heart Disease

In patients with end-stage heart failure (HF), a total artificial heart (TAH) may be implanted as a bridge to cardiac transplant. However, in congenital heart disease (CHD), the malformed heart presents a challenge to TAH implantation. 
In the case presented here, a 17 year-old patient with congenital transposition of the great arteries (CCTGA) experienced progressively worsening HF due to his congenital condition. He was hospitalized multiple times and received an implantable cardioverter defibrillator (ICD). However, his condition soon deteriorated to end-stage HF with multisystem organ failure. 
Due to the patient's grave clinical condition and the presence of complex cardiac lesions, the decision was made to proceed with a TAH. The abnormal arrangement of the patient's ventricles and great arteries required modifications to the TAH during implantation.
With the TAH in place, the patient was able to return home and regain strength and physical well-being while awaiting a donor heart. He was successfully bridged to heart transplantation 5 months after receiving the device. This report highlights the TAH is feasible even in patients with structurally abnormal hearts, with technical modification.

This is a case report of a patient with congenitally corrected transposition of the great arteries (CCTGA) who received a total artificial heart (TAH) as a bridge to heart transplant. The TAH was successfully implanted with modifications to accommodate the patient's congenitally malformed heart.

In patients with end-stage heart failure (HF), a total artificial heart (TAH) may be implanted as a bridge to cardiac transplant. However, in congenital ...

Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction

In orthopedic patients, foreign body-associated infections, especially periprosthetic joint infections (PJIs), are a devastating complication of arthroplasty. Infection requires complex treatment, may result in long hospitalization and causes considerable costs. Multiple surgical revisions can be necessary in these patients, with a loss in function as well as in quality of life.
The routine preoperative diagnostics include blood examination for C-reactive protein (CRP) and other biomarkers, as well as joint aspirate analysis for cell count, differentiation, and culture. Intraoperative specimens for histology and microbiology are also standard procedure. The microbiological examination of removed implants with sonication, in combination with the implementation of molecular biology techniques in microbiology, represent two novel techniques currently employed to enhance the differential diagnostics of PJI.
We present here the step-wise procedure of analyzing joint aspirate and sonication fluid, using a cartridge-based multiplex polymerase chain reaction (PCR) system. Results were matched against conventional cultures and consensus criteria for PJI. Conventional microbiological cultures from tissue biopsies, joint aspirate and sonication fluid showed a sensitivity of 66.7%, 66.7%, and 88.9%, respectively, and a specificity of 82.3%, 54.6%, and 61.5%, respectively. The PCR diagnostic of the sonication fluid and the joint fluid showed a sensitivity of 50.0% and 55.6%, respectively, and both a specificity of 100.0%. Both PCR diagnostics combined had a sensitivity of 66.7% and a specificity of 100.0%. The multiplex PCR therefore presents a rapid diagnostic tool with moderate sensitivity but high specificity in diagnosing PJI.

Differential diagnostics in painful arthroplasty is crucial for treatment success. Joint aspiration is routinely performed preoperatively. Multiplex polymerase chain reaction of the joint aspirate and the sonication fluid, a feasible tool for quick pathogen detection from these samples is described.

In orthopedic patients, foreign body-associated infections, especially periprosthetic joint infections (PJIs), are a devastating complication of ...

Use of Two Intracorporeal Ventricular Assist Devices As a Total Artificial Heart

Mechanical circulatory support (MCS) has been introduced as a viable alternative to heart transplantation primarily through the use of intracorporeal ventricular assist devices (VADs) for support of the left ventricle. However, certain clinical scenarios warrant biventricular mechanical support. One strategy for some patients is the excision of both ventricles and the implantation of two VAD pumps as a total artificial heart (TAH). This has recently been made possible by the improvements in device design and the small profile of centrifugal devices. This TAH approach remains experimental with many important challenges such as the device settings to balance the right and left circulation, the orientation of the devices and the outflow graft with their influence on hemolysis and stability, and the outcome of chronic support using such an orientation. This protocol aims to provide a reproducible approach for total artificial heart replacement with two intracorporeal centrifugal VADs in a cow model.

Here, we present a protocol using two centrifugal pumps as a total artificial heart replacement.

Mechanical circulatory support (MCS) has been introduced as a viable alternative to heart transplantation primarily through the use of intracorporeal ...

Generation of Human Nasal Epithelial Cell Spheroids for Individualized Cystic Fibrosis Transmembrane Conductance Regulator Study

While the introduction of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulator drugs has revolutionized care in Cystic Fibrosis (CF), the genotype-directed therapy model currently in use has several limitations. First, rare or understudied mutation groups are excluded from definitive clinical trials. Moreover, as additional modulator drugs enter the market, it will become difficult to optimize the modulator choices for an individual subject. Both of these issues are addressed with the use of patient-derived, individualized preclinical model systems of CFTR function and modulation. Human nasal epithelial cells (HNEs) are an easily accessible source of respiratory tissue for such a model. Herein, we describe the generation of a three-dimensional spheroid model of CFTR function and modulation using primary HNEs. HNEs are isolated from subjects in a minimally invasive fashion, expanded in conditional reprogramming conditions, and seeded into the spheroid culture. Within 2 weeks of seeding, spheroid cultures generate HNE spheroids that can be stimulated with 3',5'-cyclic adenosine monophosphate (cAMP)-generating agonists to activate CFTR function. Spheroid swelling is then quantified as a proxy of CFTR activity. HNE spheroids capitalize on the minimally invasive, yet respiratory origin of nasal cells to generate an accessible, personalized model relevant to an epithelium reflecting disease morbidity and mortality. Compared to the air-liquid interface HNE cultures, spheroids are relatively quick to mature, which reduces the overall contamination rate. In its current form, the model is limited by low throughput, though this is offset by the relative ease of tissue acquisition. HNE spheroids can be used to reliably quantify and characterize CFTR activity at the individual level. An ongoing study to tie this quantification to in vivo drug response will determine if HNE spheroids are a true preclinical predictor of patient response to CFTR modulation.

Here we describe a method to generate three-dimensional spheroid cultures of human nasal epithelial cells. Spheroids are then stimulated to drive Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)-dependent ion and fluid secretion, quantifying the change in the spheroid luminal size as a proxy for CFTR function.

While the introduction of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulator drugs has revolutionized care in Cystic Fibrosis (CF), the ...

An In Vivo Mouse Model of Total Intravenous Anesthesia During Cancer Resection Surgery

Anesthesia is a routine component of cancer care that is used for diagnostic and therapeutic procedures. The anesthetic technique has recently been implicated in impacting long-term cancer outcomes, possibly through modulation of adrenergic-inflammatory responses that impact cancer cell behavior and immune cell function. Emerging evidence suggests that propofol-based total intravenous anesthesia (TIVA) may be beneficial for long-term cancer outcomes when compared to inhaled volatile anesthesia. However, the available clinical findings are inconsistent. Preclinical studies that identify the underlying mechanisms involved are critically needed to guide the design of clinical studies that will expedite insight. Most preclinical models of anesthesia have been extrapolated from the use of anesthesia in in vivo research and are not optimally designed to study the impact of anesthesia itself as the primary endpoint. This paper describes a method for delivering propofol-TIVA anesthesia in a mouse model of breast cancer resection that replicates key aspects of clinical delivery in cancer patients. The model can be used to study mechanisms of action of anesthesia on cancer outcomes in diverse cancer types and can be extrapolated to other non-cancer areas of preclinical anesthesia research.

An In Vivo Mouse Model of Total Intravenous Anesthesia During Cancer Resection Surgery

This paper describes a method for modeling total intravenous anesthesia (TIVA) during cancer resection surgery in mice. The goal is to replicate key features of anesthesia delivery to patients with cancer. The method allows investigation of how anesthetic technique affects cancer recurrence after resection surgery.

Anesthesia is a routine component of cancer care that is used for diagnostic and therapeutic procedures. The anesthetic technique has recently been ...

In Vivo Quantification of Hip Arthrokinematics during Dynamic Weight-bearing Activities using Dual Fluoroscopy

Several hip pathologies have been attributed to abnormal morphology with an underlying assumption of aberrant biomechanics. However, structure-function relationships at the joint level remain challenging to quantify due to difficulties in accurately measuring dynamic joint motion. The soft tissue artifact errors inherent in optical skin marker motion capture are exacerbated by the depth of the hip joint within the body and the large mass of soft tissue surrounding the joint. Thus, the complex relationship between bone shape and hip joint kinematics is more difficult to study accurately than in other joints. Herein, a protocol incorporating computed tomography (CT) arthrography, three-dimensional (3D) reconstruction of volumetric images, dual fluoroscopy, and optical motion capture to accurately measure the dynamic motion of the hip joint is presented. The technical and clinical studies that have applied dual fluoroscopy to study form-function relationships of the hip using this protocol are summarized, and the specific steps and future considerations for data acquisition, processing, and analysis are described.

In Vivo Quantification of Hip Arthrokinematics during Dynamic Weight-bearing Activities using Dual Fluoroscopy

Dual fluoroscopy accurately captures in vivo dynamic motion of human joints, which can be visualized relative to reconstructed anatomy (e.g., arthrokinematics). Herein, a detailed protocol to quantify hip arthrokinematics during weight-bearing activities of daily living is presented, including the integration of dual fluoroscopy with traditional skin marker motion capture.

Several hip pathologies have been attributed to abnormal morphology with an underlying assumption of aberrant biomechanics. However, structure-function ...

Robot-assisted Total Mesorectal Excision and Lateral Pelvic Lymph Node Dissection for Locally Advanced Middle-low Rectal Cancer

Since their approval for clinical use, da Vinci surgical robots have shown great advantages in gastrointestinal surgical operations, especially in complex procedures. The high-quality 3-D visual, multijoint arm and natural tremor filtration allow the surgeon to expose and dissect more accurately with minimal invasion. Total mesorectal excision is the standard surgical technique for the treatment of resectable rectal cancer. To reduce the lateral recurrence rate, lateral pelvic lymph node dissection can be performed, as it is a safe and feasible procedure for locally advanced middle-low rectal cancer with a high possibility of metastasis to the lateral lymph nodes. However, the complexity of the anatomic structures and the high postoperative complication rate limit its application. Recently, several surgeons have increasingly used robotic techniques for total mesorectal excision and lateral pelvic lymph node dissection. Compared with open and laparoscopic surgery, the robotic technique has several advantages, such as less blood loss, fewer blood transfusions, minimal trauma, shorter postoperative hospitalization, and quicker recovery. A robotic approach is generally regarded as a reasonable alternative for complicated procedures such as lateral pelvic lymph node dissection, although there are a limited number of high-quality prospective randomized controlled studies reporting direct evidence. Here, we provide the detailed steps of robot-assisted total mesorectal excision and lateral pelvic lymph node dissection performed at the First Affiliated Hospital of Xi&#39;an Jiaotong University.

The robotic technique described herein aims to detail a stepwise approach to robot-assisted total mesorectal excision and lateral pelvic lymph node dissection for locally advanced (T3/T4) rectal cancer located below the peritoneal reflection.

Since their approval for clinical use, da Vinci surgical robots have shown great advantages in gastrointestinal surgical operations, especially in complex ...