A New Minimally Invasive Transsartorial Approach for Periacetabular Osteotomy

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1 This is an enhance PDF from The Journal of Bone an Joint Surgery The PDF of the article you requeste follows this cover page. A New Minimally Invasive Transsartorial Approach for Periacetabular Osteotomy A. Troelsen, B. Elmengaar an K. Søballe J Bone Joint Surg Am. 2008;90: oi: /jbjs.f This information is current as of March 3, 2008 Supplementary material Reprints an Permissions Publisher Information Commentary an Perspective, ata tables, aitional images, vieo clips an/or translate abstracts are available for this article. This information can be accesse at Click here to orer reprints or request permission to use material from this article, or locate the article citation on jbjs.org an click on the [Reprints an Permissions] link. The Journal of Bone an Joint Surgery 20 Pickering Street, Neeham, MA

2 493 COPYRIGHT Ó 2008 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED A New Minimally Invasive Transsartorial Approach for Periacetabular Osteotomy By A. Troelsen, MD, B. Elmengaar, MD, PhD, an K. Søballe, MD, DMSc Investigation performe at the Orthopaeic Research Unit, University Hospital of Aarhus, Aarhus, Denmark Backgroun: A new minimally invasive transsartorial approach for the Bernese periacetabular osteotomy was evelope. We investigate whether this technique was safe an successful with regar to minimizing tissue trauma an, more importantly, whether it was possible to obtain optimal reorientation of the acetabulum. Methos: Our experience with this approach was retrospectively assesse by means of atabase inquiry an the evaluation of raiographs. We assesse ninety-four proceures performe between April 2003 an August 2005 to etermine perioperative an early postoperative outcome measures, the achieve acetabular reorientation, an hip joint survival. Results: The mean uration of surgery was 73.1 minutes, the meian perioperative bloo loss was 250 ml, an the mean reuction in the hemoglobin level was 33 g/l. Bloo transfusion was require following 3% of the proceures. No injuries to the great vessels or nerves, arterial thromboses, unintene extension of the osteotomy, or eep infections occurre. The postoperative acetabular reorientation was assesse by measuring the center-ege an acetabular inex angles, the meians of which were 34 an 3, respectively. With total hip arthroplasty as the en point, the hip joint survival rate was estimate to be 98% at 4.3 years. Conclusions: Osteotomy with use of this minimally invasive transsartorial approach appears to be a safe, relatively short surgical proceure associate with a relatively small amount of bloo loss an minimal transfusion requirements. Optimal acetabular reorientation can be achieve with this technique. Level of Evience: Therapeutic Level IV. See Instructions to Authors for a complete escription of levels of evience. Ganz et al. escribe a technique of periacetabular osteotomy in It is an extensive surgical proceure performe in young aults with acetabular ysplasia The acetabulum is reoriente in orer to optimize its coverage of the femoral hea, thereby changing the pathological hip joint mechanics that can cause early osteoarthritis The learning curve associate with this proceure is well ocumente, an technical an neurovascular complications have been reporte by experience surgeons 1,7, The occurrence of complications is greatly influence by the experience of the surgeon an the choice of surgical approach 23,25. Several approaches for the Bernese periacetabular osteotomy are characterize by relatively extensive incisions an issection an may require muscle etachment 1,3-5,25-28.Themost commonly use approaches are the moifie Smith-Petersen (iliofemoral) an the ilioinguinal approaches 3-5,21,25,28. A new, minimally invasive, transsartorial approach for the periacetabular osteotomy was evelope by the senior au- Disclosure: The authors i not receive any outsie funing or grants in support of their research for or preparation of this work. One or more of the authors, or a member of his or her immeiate family, receive, in any one year, payments or other benefits of less than $10,000 or a commitment or agreement to provie such benefits from a commercial entity (the measuring evice use in the stuy is a commercially available prouct evelope by one of the authors). No commercial entity pai or irecte, or agree to pay or irect, any benefits to any research fun, founation, ivision, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immeiate families, are affiliate or associate. A vieo supplement to this article will be available from the Vieo Journal of Orthopaeics. A vieo clip will be available at the JBJS web site, The Vieo Journal of Orthopaeics can be contacte at (805) , web site: A commentary is available with the electronic versions of this article, on our web site ( an on our quarterly CD-ROM (call our subscription epartment, at , to orer the CD-ROM). J Bone Joint Surg Am. 2008;90:493-8 oi: /jbjs.f.01399

3 494 thor (K.S.). The primary aim of this approach was to minimize the tissue trauma uring issection. As a result, the uration of surgery, bloo loss, transfusion requirements, an length of hospital stay may be minimize. However, it is necessary for this approach to be safe, an the rate of complications shoul be lower or comparable with that of currently accepte techniques. The reorientation of the acetabulum shoul not be compromise, since it is the cornerstone of the proceure. The purpose of this stuy was to investigate if this new approach is safe an oes not aversely affect optimal acetabular reorientation. Materials an Methos We retrospectively assesse our experience with the minimally invasive transsartorial approach by means of atabase inquiry an evaluation of raiographs. Between April 2003 an August 2005, this approach was use in 122 patients (125 proceures, three of which were bilateral) unergoing periacetabular osteotomy. All patients were operate on by the senior author (K.S.). The approach was use in consecutive patients, with no selection. Our inications for the osteotomy were symptomatic acetabular ysplasia efine by persistent hip pain an a center-ege angle of Wiberg 29 of <25,acongruent hip joint, no or early signs of osteoarthritis (Tönnis grae 30 0or 1), hip flexion of >110, an internal rotation of >15. Stuy Group All patients who ha been operate on with use of the periacetabular osteotomy between April 2003 an August 2005 were eligible for inclusion. In orer to provie a well-efine stuy group, we exclue patients who ha not unergone surgery with hypotensive epiural anesthesia (three patients), patients who ha ha supplemental hip surgery (harware removal, intertrochanteric osteotomy, or cheilectomy; nine patients), an those with Legg-Calvé-Perthes isease (nineteen patients). Ninety-one patients who ha unergone a total of ninety-four proceures (three of which were bilateral) satisfie the criteria an comprise the stuy group. At the time of surgery, the mean age of the patients was 37.2 years (95% confience interval, 34.9 to 39.5 years), their mean weight was 68.5 kg (95% confience interval, 66.1 to 70.8 kg), an seventy-six (84%) were women. The uration of follow-up for assessment of hip joint survival in the stuy group range from 2.0 to 4.3 years. Clinical an Raiographic Evaluation The stuy group was assesse with respect to the uration of the surgery, perioperative bloo loss, reuction in hemoglobin level, transfusion requirements, complications, length of hospital stay, reorientation of the acetabulum, an nee for a subsequent total hip arthroplasty. Data regaring age, gener, weight, iagnosis, length of hospital stay, previous surgery, surgical approach, metho of anesthesia, uration of surgery, perioperative bloo loss, perioperative supplemental surgery, transfusion requirements, an complications ha been recore in a atabase assigne to the Danish Hip Arthroplasty Register. Furthermore, preoperative an postoperative bloo specimens ha been taken routinely from all patients for etermination of hemoglobin values, an anteroposterior pelvic raiographs ha been mae routinely for all patients. Patients who ha a subsequent total hip arthroplasty in a Danish hospital were registere in the Danish Hip Arthroplasty Register. Therefore, patients who were living outsie of Denmark (five patients treate with a total of seven proceures [two bilateral]) were not available for the hip joint survival analysis. The uration of surgery was measure from the start of the skin incision to the completion of the skin closure. The perioperative bloo loss was estimate on the basis of the volume of bloo in the suction bottles an swabs in the operating room. A bloo transfusion was not performe uring any of the proceures. Postoperative bloo transfusion was prescribe on the basis of clinical symptoms of anemia. Moerate an severe complications (that is, an injury to the great vessels or nerves, an arterial thrombosis, unintene extension of the osteotomy into the joint or through the posterior column, or eep infection) were recore in the atabase. Minor complications (such as ysesthesia of the lateral femoral cutaneous nerve, elaye union, or heterotopic ossification) were not. The orientation of the acetabulum was etermine by measuring the center-ege angle of Wiberg 29 an the acetabular inex angle of Tönnis 30. The center-ege angle is forme by two lines, both running through the center of the femoral hea. The first line is perpenicular to the pelvic reference line, an the secon line is rawn from the most lateral margin of the acetabular sclerotic roof. The acetabular inex angle is forme by two lines, both originating at the most meial margin of the sclerotic acetabular roof. The first line is parallel to the pelvic reference line, an the secon line is rawn to the most lateral margin of the sclerotic acetabular roof. The same observer (A.T.) mae the measurements on both preoperative an postoperative anteroposterior pelvic raiographs. Raiographs relate to seven proceures were missing or of inferior quality (excessive tilt or rotation) an were exclue from evaluation. The hemoglobin values relate to seven proceures were also exclue either because they were missing (one proceure) or because the patient ha ha a bilateral proceure. The weight ata for one patient were missing from the register. Data were complete for the remaining parameters. Surgical Technique The patient is place on a raiolucent operating room table in the supine position. The placement of the rapes allows full mobilization of the lower extremity on the operatively treate sie. Fluoroscopic evaluation is necessary throughout the operation, an therefore the pelvis is kept in a neutral position in orer to avoi excessive tilting or rotation. The fluoroscopy equipment is positione to facilitate the attainment of anteroposterior an 60 (false-profile) views. The skin incision begins at the anterior superior iliac spine an continues istally along the sartorius muscle. The length of the incision is approximately 7 cm. The fascia is carefully incise, an the lateral femoral cutaneous nerve is isolate an carefully retracte. To facilitate transverse retraction of the soft tissues, a semiflexe position of the hip joint

4 495 is maintaine uring performance of the osteotomies. A splint is use for this purpose. A periosteal elevator is place subperiosteally along the meial aspect of the ilium, starting at the anterior superior iliac spine, an is avance until it lies just below the linea terminalis. The inguinal ligament is cut at the attachment to the anterior superior iliac spine, allowing further mobilization of the soft tissues. The periosteal elevator is then pushe meially, splitting the sartorius muscle in the irection of its fibers, an the eep fascia of the muscle is cut. The periosteal elevator is then replace with a blunt retractor positione along the meial aspect of the ilium to retract the iliopsoas muscle an the meial part of the split sartorius muscle meially. At this point, the osteotomies are performe (Fig. 1). We estimate that approximately ten minutes is spent on the approach. A etaile technical escription of the periacetabular osteotomy is presente in the Appenix. Statistical Analysis Normally istribute ata are presente as means with 95% confience intervals. Data that are not normally istribute are presente as meians with interquartile ranges. The surgeon s learning curve with respect to the uration of surgery an perioperative bloo loss was analyze with linear regression analysis. Kaplan-Meier survival analysis was performe with a subsequent total hip arthroplasty as the en point. The level of significance was set at p < TABLE I Clinical Measures Associate with the Minimally Invasive Transsartorial Approach Measurement Meian length of hospital stay 8 (7-9) (interquartile range) (ays) Mean uration of surgery (95% 73.1 ( ) confience interval) (min) Meian perioperative bloo loss 250 ( ) (interquartile range) (ml) Mean preoperative hemoglobin level 138 ( ) (95% confience interval) (g/l) Mean reuction in hemoglobin level 33 (31-35) (95% confience interval) (g/l) No. (%) of proceures followe by transfusion 3 (3%) Meian no. of bloo units transfuse (range) 2 (2-3) Results Clinical Outcome The meian length of the hospital stay was eight ays (interquartile range, seven to nine ays), the mean uration of the surgery was 73.1 minutes (95% confience interval, 70.5 to 75.8 minutes), an the meian measure perioperative bloo loss was 250 ml (interquartile range, 150 to 350 ml) Fig. 1 Performance of the osteotomy through the minimally invasive transsartorial approach. A straight osteotome is use to perform the last step of the ilium osteotomy, with a retractor protecting the meial structures (see Appenix for etails).

5 496 TABLE II Raiographic Measurements Associate with the Minimally Invasive Transsartorial Approach Measurement Meian center-ege angle of Wiberg (interquartile range) (eg) Preoperative 15 (6-19) Postoperative 34 (29-36) Meian acetabular inex angle of Tönnis (interquartile range) (eg) Preoperative 17 (14-23) Postoperative 3 (0-7) (Table I). No particular learning curve for the surgeon was ientifie by the linear regression analysis, which emonstrate a negligible ecrease in the uration of surgery (r = 20.05). There was no significant relationship between the number of proceures performe an the uration of surgery (p = 0.35). Bloo transfusions were require following 3% (three) of the ninety-four proceures, with a meian of two (range, two to three) units of bloo (280 ml of erythrocyte suspension) transfuse. The mean preoperative hemoglobin level was 138 g/l (95% confience interval, 136 to 140 g/l). The mean reuction in the hemoglobin level was 33 g/l (95% confience interval, 31 to 35 g/l) (Table I). With conversion to total hip arthroplasty as the en point, the Kaplan-Meier analysis showe a hip joint survival rate of 98% at 4.3 years (range of follow-up, 2.0 to 4.3 years) (Fig. 2). There were two conversions to total hip arthroplasty, one at 1.8 years an one at 2.7 years after the osteotomy. Complications There were no arterial thromboses, injuries of the iliac or femoral artery or vein, injuries of the femoral or sciatic nerve, or irect injuries of the lateral femoral cutaneous nerve. There were no observe instances of unintene extension of the osteotomy through the posterior column or into the joint. There were no woun infections requiring surgical intervention. Raiographic Outcome The meian center-ege angle was 15 (interquartile range, 6 to 19 ) preoperatively an 34 (interquartile range, 29 to 36 ) postoperatively. The meian acetabular inex angle was 17 (interquartile range, 14 to 23 ) preoperatively an 3 (interquartile range, 0 to 7 ) postoperatively (Table II). The istributions of the preoperative an postoperative center-ege an acetabular inex angles are presente in the Appenix. Discussion Periacetabular osteotomy is an extensive surgical proceure, an the most commonly use approaches are associate with relatively extensive tissue trauma 1,5,25,28. In an attempt to minimize the tissue trauma cause by incision, issection, an etachment of muscles, the senior author (K.S.) evelope a minimally invasive approach for the proceure. In the pre- Fig. 2 Kaplan-Meier hip joint survivorship curve with 95% confience intervals for eighty-seven periacetabular osteotomies (seven proceures in patients living outsie of Denmark were exclue) with conversion to a total hip arthroplasty as the en point. The uration of follow-up was 2.0 to 4.3 years.

6 497 sent stuy, we attempte to etermine if this approach was safe an i not compromise the achieve reorientation of the acetabulum. The minimally invasive characteristics of this approach are evient at all stages of the proceure an are not efine by the length of the skin incision. No muscles are etache, an the only muscle that is irectly affecte is the sartorius, which issplitintheirectionofthefibers.thetissuetraumais further minimize by the relatively brief uration of the surgery (mean, 73.1 minutes), which is ue in part to the limite time spent on the approach an closure. The relatively small perioperative bloo loss an low transfusion requirements also suggest minimal soft-tissue trauma. However, all bloo loss may not be recognize with use of the methos for assessing perioperative bloo loss that we employe 31. The uration of the surgery, perioperative bloo loss, an transfusion requirements with our technique compare favorably with those associate with other techniques reporte in the literature 1-5,7,23,27. Trousale an Cabanela reporte an average bloo loss of 350 ml in patients treate through an iliofemoral approach 24. Siebenrock et al. reporte that the patients in their stuy require transfusion of a mean of four units (range, one to eleven units) of bloo, but approximately 25% of those patients ha simultaneous supplemental surgery 2. The uration of the hospital stay that we reporte is similar to the seven to ten-ay urations reporte by authors who ha use ifferent surgical approaches 4,5,27. When a transsartorial approach is use, the sartorius an iliopsoas muscles protect the femoral vessels an nerve against irect an inirect amage. The abuctor muscles are spare, an the acetabular bloo supply is therefore left intact. We observe no moerate or severe neurovascular or technical complications. When iliofemoral approaches are use, the prevalence of moerate or severe technical an neurovascular complications shoul be less than 2% to 3% 1,23,25. Minor complications were not registere in the atabase, an we i not evaluate them in this stuy. Such minor complications inclue ysesthesia of the lateral femoral cutaneous nerve, which was reporte to have occurre after approximately 30% of more than 700 periacetabular osteotomies performe through the moifie Smith-Petersen (iliofemoral) approach 25. The meian postoperative center-ege an acetabular inex angles of 34 an 3, respectively, show that acceptable acetabular reorientation was achieve. The istribution of the postoperative angle measurements shows that nearly normal alignment was obtaine in a high proportion of patients. We aim for an acetabular inex angle of 0 to 10 an a centerege angle of 30 to 40 ; however, this amount of correction might not be achieve if the hip is severely ysplastic. Since September 1999, we have use a measuring evice to assist in surgical ecision-making uring the reorientation proceure. The evice provies measurements of the perioperative centerege an acetabular inex angles with the use of fluoroscopy. Even though we o not perform an extensive soft-tissue issection, we have not experience technical problems, an the achieve angle measures are comparable with those reporte in what we believe are the largest stuy groups in the literature 2,3,7. Hip joint survivorship analysis with total hip arthroplasty as the en point estimate a survival rate of 98% at 4.3 years. There were only two short-term conversions to total hip arthroplasty (both in hips that were Tönnis grae 1 preoperatively). The high survival rate was likely ue to our inications for performing the periacetabular osteotomy. In a previous stuy 32 in which short-term hip joint survivorship was reporte with total hip arthroplasty or an aitional osteotomy as the en point, the lowest survival rates were foun in patients with moerate or severe osteoarthritis (Tönnis grae 2 or 3). The minimally invasive approach limits irect visualization of the osteotomies. This coul increase the risk of intraarticular extension of the osteotomy or extension of the osteotomy through the posterior column 22. However, with use of the fluoroscopic technique that we escribe (see Appenix), no such cases were observe. We estimate that the average fluoroscopy time was approximately thirty-five secons. It is not possible to access the labrum or other intraarticular structures with this approach, an some surgeons may fin this to be a major limitation. However, we o not consier intra-articular assessment to be necessary. It is important to recognize that there is a learning curve relate to this proceure 1, The experience of the surgeon is an important factor that greatly influences the result. When this minimally invasive approach was initiate, the senior author ha alreay accumulate great experience with respect to the etails of the reorientation proceure by previously performing 143 Bernese periacetabular osteotomies. Furthermore, this stuy i not emonstrate a significant relationship between the number of proceures performe an the uration of the surgery. We recommen that only a surgeon with previous experience with the performance of periacetabular osteotomy consier using our minimally invasive approach. Our results suggest that this minimally invasive approach is safe an successful in minimizing tissue trauma. There were no moerate or severe technical or neurovascular complications in our series. The postoperative center-ege an acetabular inex angles were highly satisfactory. All proceures were performe by an experience surgeon, an it is not known whether these results can be achieve by less experience surgeons. This an the full scope of benefits an isavantages of the approach will nee to be reveale in subsequent stuies. Appenix Details of the periacetabular osteotomy an the istributions of the center-ege an acetabular inex angles before an after the surgery are available with the electronic versions of this article, on our web site at jbjs.org (go to the article citation an click on Supplementary Material ) an on our quarterly CD-ROM (call our subscription epartment, at , to orer the CD-ROM). n NOTE: The authors thank Søren P. Johnsen, Aners Riis, an Alma B. Peersen, Department of Clinical Epiemiology, University of Aarhus, Denmark, for their great contribution to the evelopment an construction of the atabase an for their assistance with the statistical analyses of patient ata.

7 498 A. Troelsen, MD B. Elmengaar, MD, PhD K. Søballe, MD, DMSc Orthopaeic Research Unit, University Hospital of Aarhus, Builings 7B (A.T. an B.E.) an 1B (K.S.), Tage-Hansens Gae 2, DK-8000 Aarhus, Denmark. aress for A. Troelsen: aress for B. Elmengaar: aress for K. Søballe: References 1. Ganz R, Klaue K, Vinh TS, Mast JW. A new periacetabular osteotomy for the treatment of hip ysplasias. Technique an preliminary results. Clin Orthop Relat Res. 1988;232: Siebenrock KA, Scholl E, Lottenbach M, Ganz R. Bernese periacetabular osteotomy. Clin Orthop Relat Res. 1999;363: Trumble SJ, Mayo KA, Mast JW. The periacetabular osteotomy. Minimum 2 year followup in more than 100 hips. Clin Orthop Relat Res. 1999;363: Matta JM, Stover MD, Siebenrock K. Periacetabular osteotomy through the Smith-Petersen approach. Clin Orthop Relat Res. 1999;363: Pogliacomi F, Stark A, Wallensten R. Periacetabular osteotomy. Goo pain relief in symptomatic hip ysplasia, 32 patients followe for 4 years. 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