Millis, Michael

Siebenrock, Klaus

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SYMPOSIUM: ABJS CARL T. BRIGHTON WORKSHOP ON HIP PRESERVATION SURGERYReport of Breakout SessionDefining Parameters for Correcting the Acetabulum During a PelvicReorientation OsteotomyMichael B. Millis MD (Moderator),Klaus A. Siebenrock MD (Scribe),Session ParticipantsPublished online: 10 July 2012 The Association of Bone and Joint Surgeons1 2012Where Are We Now?Treatment of typical developmental dysplasia of the hip(DDH) addresses instability and abnormal load transmis-sion to the hyaline cartilage based on acceptedbiomechanical concepts. The treatment goal is to obtain adurably pain-free and functional hip. It remains unclearwhether surgery can delay or prevent early osteoarthritis [5,7, 10, 11] and if so in which patients.We believe adolescent and young patients with pain in adysplastic hip in the absence of advanced osteoarthriticsigns and a good ROM are the best candidates for surgicalcorrection of the deformity [2, 10, 11]. There is agreementthat a pelvic osteotomy with reorientation of the acetabu-lum is the procedure of choice. Preoperative imagingshould include an AP pelvis radiograph, a lateral view, anda false-profile view. In patients with joint incongruency onthe AP pelvis view, we recommend an AP pelvis radio-graph with bilateral hip abduction, internal rotation, andabout 15 of flexion. This functional view can provide asense of the joint geometry after a surgical reorientation ofthe acetabulum. Radiographic analysis includes evaluationfor joint instability [2], which seems to be represented bythe following: lateral and cranial migration of the femoralhead best seen by a superomedial widening of the jointspace and a marked difference between the center of thehead and the acetabulum, a broken Shenton’s line, andcranial narrowing and posterior widening of the joint spaceon a false-profile view.Further radiographic analysis must implement estab-lished parameters for measuring a deficient acetabularcoverage and abnormal version: the lateral center-edgeangle (LCE); orientation of the roof (anterior center-edge[ACE] angle); lateralization of the head center in respect tothe ilioischial line; version of the acetabulum defined bythe outline of the anterior and posterior rim, as well as thepresence or absence of a crossover sign; and alpha angle toidentify an abnormal head-neck junction.Frequently used reorientation procedures of the acetab-ulum are a triple osteotomy, a spherical or rotationalosteotomy, and a Bernese periacetabular osteotomy. Weagree intraoperative evaluation of the reoriented acetabu-lum should be mandatory. Commonly, an intraoperativeAP pelvis radiograph is taken to judge correction. Plainpelvic radiographs during surgery in a supine position canbe compared to pre- and postoperative radiographs. As arule, the tube-to-film distance typically is 1.20 m, with thecentral beam located in the middle between the upperSession Participants: William Jiranek MD, Yuji Yasunaga MD, PhD.W. JiranekDepartment of Orthopaedic Surgery, Virginia CommonwealthUniversity, Richmond, VA, USAY. YasunagaDepartment of Orthopaedic Surgery, Hiroshima UniversityKasumi, Minami-ku Hiroshima, JapanEach author certifies that he or she, or a member of his or herimmediate family, has no commercial associations (eg, consultancies,stock ownership, equity interest, patent/licensing arrangements, etc)that might pose a conflict of interest in connection with the submittedarticle.All ICMJE Conflict of Interest Forms for authors and ClinicalOrthopaedics and Related Research editors and board members areon file with the publication and can be viewed on request.M. B. MillisDepartment of Orthopaedic Surgery, Harvard Medical SchoolChildren’s Hospital, Boston, MA, USAK. A. Siebenrock (&)Department of Orthopaedic Surgery, Universityof Bern, Inselspital, Bern, Switzerlande-mail: klaus.siebenrock@insel.ch123Clin Orthop Relat Res (2012) 470:3453–3455DOI 10.1007/s11999-012-2426-0Clinical Orthopaedicsand Related Research®A Publication of  The Association of Bone and Joint Surgeons®border of the symphysis and a line connecting the twoanterior superior iliac spines [9]. Deviation of the tip of thecoccyx from the middle of the symphysis indicates mal-orientation of the pelvis, and after repositioning of thepatient, the radiograph should be repeated. With the use ofadditional tools or more sophisticated orientation of thex-ray beam, fluoroscopy also can be used for intraoperativeevaluation of the corrected acetabulum [6, 14].Spatial acetabular orientation can be identified by out-lining the contours of the anterior and posterior rim.Recommendations for defining the correction parameterscan only be given in ranges and not to the exact degree andshould be adapted to the individual pathomorphology.There is general agreement about the useful parameters andrecommended goals: an LCE angle of between 20 and35, preferably in the upper 20s; an ACE angle of between0 and 10, preferably in the upper range; head medial-ization with a distance of the medial femoral head to theilioischial line of less than 10 mm; restoration of Shenton’sline; a weightbearing dome centered over the head; ante-version of the acetabulum as defined by the absence of acrossover sign and the outlines of the anterior and posteriorrim meeting at the lateral acetabular edge; and restorationof hip congruency [1, 4, 11, 13].Two additional issues seem essential after reorientationand preliminary fixation of the dysplastic acetabulum.(1) In cases of joint incongruency, intraoperative functionalviews in abduction or adduction should be added to con-sider the need for further improvement of acetabularreorientation or an additional intertrochanteric osteotomy.(2) Improvement of anterior coverage bears the risk foranterior femoroacetabular impingement. Thus, the need foradditional improvement of the head-neck offset in hipswith a restricted internal rotation (IR) should be considered[8, 15]. However, this issue is controversial at this time. Onthe one hand, while most authors agree restricted IR shouldlead to an exclusion of impingement of the neck against theanterior rim or anterior inferior spine, there is no agreementas to the exact degree of IR needed; an IR of less than 15to 30 could be considered crucial for initiating anarthrotomy. On the other hand, some authors do not con-sider improvement of the offset a necessary step duringacetabular reorientation and question its influence on finaloutcome [14].Where Do We Need To Go?We are aware, in the majority of cases, not all parameterscan be idealized due to the deficient nature of a dysplastichip. In the future, predictive values and the adequate rangeof the recommended parameters must be analyzed andvalidated in regard to long-term survival of operated hips.This may include new and easily applicable parameters forquantification of anterior and posterior wall coverage ordome orientation. We should analyze to what degree cor-rection of acetabular version and especially improvementof the head-neck offset will influence long-term functionand durability of the hip. The key question will be howwell we can delay progression to disabling osteoarthritis inthese patients.We also believe ideal correction in the future should betailored to the individual hip. Pathomorphologic features ofthe proximal femur in DDH seem underestimated [11] andpublished studies largely ignore potential important factorssuch as torsional deformities of the femur. Objectivemeasurements of achieved head coverage and the mor-phology of the femur are mandatory.How Do We Get There?More long-term (20 years or more) studies will be neededto answer questions concerning the degree and duration offunctional improvement. Ultimately, these studies willprovide an answer concerning the efficiency of delaying orpreventing osteoarthritis when compared to publishedstudies about the natural course of osteoarthritis in DDH [5,7]. Multicenter studies might speed up this process since alarger number of patients could be gathered in a shorterperiod of time. Postoperative analysis should include rou-tine measurement of acetabular and femoral torsion, aswell as head sphericity and head-neck offset [8] and theirinfluence on outcome. An identified list of predictive fac-tors will likely improve patient selection and help to find aconsensus for the key parameters to achieve more favor-able results. This would also give hints as to whetherselected individual hips might benefit from a differentdegree of acetabular orientation.We also believe there is a place for more elaboratethree-dimensionally based planning and navigation tools inthe future. This also would include the amount and effectof torsional deformities of the femur and acetabulum.Computer-animated motion of individual hips may help toidentify a potential postoperative impingement conflictand/or allow for more sophisticated preoperative planning[12]. An efficient and simple navigation tool during ace-tabular reorientation likely would facilitate the procedureand make reorientation more reproducible.Ultimately, modern imaging techniques such as delayedgadolinium-enhanced MRI of cartilage (dGEMRIC) scansof the hip may predict early failure in preoperative analysisof the cartilage condition. Low dGEMRIC indexes corre-late with failure of the osteotomy and might be animportant tool in the future for noninvasive analysis of thehip condition [3].3454 Millis et al. Clinical Orthopaedics and Related Research1123References1. Clohisy JC, Barrett SE, Gordon JE, Delgado ED, Schoenecker PL.Medial translation of the hip joint center associated with the Ber-nese periacetabular osteotomy. Iowa Orthop J. 2004;24:43–48.2. Clohisy JC, Barrett SE, Gordon JE, Delgado ED, SchoeneckerPL. Periacetabular osteotomy for the treatment of severe ace-tabular dysplasia. J Bone Joint Surg Am. 2005;87:254–259.3. Cunningham T, Jessel R, Zurakowski D, Millis MB, Kim YJ.Delayed gadolinium-enhanced magnetic resonance imaging ofcartilage to predict early failure of Bernese periacetabular oste-otomies for hip dysplasia. J Bone Joint Surg Am. 2006;88:1540–1548.4. Czubak J. Periacetabular osteotomy in the treatment of devel-opmental hip dysplasia in adolescents and adults. OrtopTraumatol Rehabil. 2006;8:12–15.5. Hartofilikdis G, Karachalios T, Slamos KG. Epidemiology,demographics, and natural history of congenital hip disease inadults. Orthopedics. 2000;23:823–827.6. Matta JM, Stover MD, Siebenrock KA. Periacetabular osteotomythrough the Smith-Petersen approach. Clin Orthop Relat Res.1999;363:21–32.7. Murphy SB, Ganz R, Mu¨ller ME. The prognosis in untreateddysplasia of the hip: a study of radiographic factors that predictthe outcome. J Bone Joint Surg Am. 1995;77:985–989.8. Myers SR, Eijer H, Ganz R. Anterior femoroacetabularimpingement after periacetabular osteotomy. Clin Orthop RelatRes. 1999;363:93–99.9. Siebenrock KA, Kalbermatten DF, Ganz R. Effect on pelvic tilton acetabular retroversion: a study of pelves from cadavers. ClinOrthop Relat Res. 2003;407:241–248.10. Siebenrock KA, Scho¨ll E, Lottenbach M, Ganz R. Berneseperiacetabular osteotomy. Clin Orthop Relat Res. 1999;363:9–20.11. Steppacher SD, Tannast M, Ganz R, Siebenrock KA. Mean 20-year followup of Bernese periacetabular osteotomy. Clin OrthopRelat Res. 2008;466:1633–1644.12. Tannast M, Kubiak-Langer M, Langlotz F, Puls M, Murphy SB,Siebenrock KA. Noninvasive assessment of femoroacetabularimpingement. J Orthop Res. 2007;25:122–131.13. Troelsen A, Elmengaard B, Romer L, Soballe K. Reliable angleassessment during periacetabular osteotomy with a new device.Clin Orthop Relat Res. 2008;466:1169–1176.14. Troelsen A, Elmengaard B, Soballe K. A new minimally invasivetranssartorial approach for periacetabular osteotomy. J Bone JointSurg Am. 2008;90:493–498.15. Ziebarth K, Balakumar J, Domayer S, Kim YJ, Millis MB.Bernese periacetabular osteotomy in males: is there an increasedrisk of femoroacetabular impingement (FAI) after Bernese peri-acetabular osteotomy? Clin Orthop Relat Res. 2011;469:447–453.Volume 470, Number 12, December 2012 Parameters for Acetabular Osteotomy Correction 3455123

Report of Breakout Session: Defining Parameters for Correcting the Acetabulum During a Pelvic Reorientation Osteotomy

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Report of Breakout Session: Defining Parameters for Correcting the Acetabulum During a Pelvic Reorientation Osteotomy

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