Does the dGEMRIC Index Recover 3 Years After Surgical FAI Correction and an Initial dGEMRIC Decrease at 1-Year Follow-up? A Controlled Prospective Study.

BACKGROUND: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) allows objective and noninvasive assessment of cartilage quality. An interim analysis 1 year after correction of femoroacetabular impingement (FAI) previously showed that the dGEMRIC index decreased despite good clinical outcome. PURPOSE: To evaluate dGEMRIC indices longitudinally in patients who underwent FAI correction and in a control group undergoing nonoperative treatment for FAI. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This prospective, comparative longitudinal study included 39 patients (40 hips) who received either operative (n = 20 hips) or nonoperative (n = 20 hips) treatment. Baseline demographic characteristics and presence of osseous deformities did not differ between groups. All patients received indirect magnetic resonance arthrography at 3 time points (baseline, 1 and 3 years of follow-up). The 3-dimensional cartilage models were created using a custom-developed deep learning-based software. The dGEMRIC indices were determined separately for acetabular and femoral cartilage. A mixed-effects model was used for statistical analysis in repeated measures. RESULTS: The operative group showed an initial (preoperative to 1-year follow-up) decrease of dGEMRIC indices: acetabular from 512 ± 174 to 392 ± 123 ms and femoral from 530 ± 173 to 411 ± 117 ms (both P < .001). From 1-year to 3-year follow-up, dGEMRIC indices improved again: acetabular from 392 ± 123 to 456 ± 163 ms and femoral from 411 ± 117 to 477 ± 169 ms (both P < .001). The nonoperative group showed no significant changes in dGEMRIC indices in acetabular and femoral cartilage from baseline to either follow-up point (all P > .05). CONCLUSION: This study showed that 3 years after FAI correction, the dGEMRIC indices improved compared with short-term 1-year follow-up. This may be due to normalized joint biomechanics or regressive postoperative activation of the inflammatory cascade after intra-articular surgery.

Retrotilt of the Pelvis During Periacetabular Osteotomy: How to Avoid a Systematic Error Resulting in Acetabular Retroversion and Possible Femoroacetabular Impingement.

BACKGROUND: Pelvic tilt directly influences acetabular version on radiographs. Changes of pelvic tilt potentially affect acetabular reorientation after periacetabular osteotomy (PAO). PURPOSE: (1) To compare the ratio of the pubic symphysis height to the sacroiliac width (PS-SI) between hips with dysplasia and acetabular retroversion, uni- and bilateral PAO, and male and female patients. (2) To evaluate pelvic tilt (quantified using the PS-SI ratio) in patients after PAO by tracking it from preoperative to intra- and postoperative and short- and middle-term follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective and radiographic study was conducted evaluating pelvic tilt in 124 patients (139 hips) with dysplasia and 46 patients (57 hips) with acetabular retroversion who were undergoing PAO (January 2005-December 2019). Patients were excluded if they had insufficient radiographic data, previous or concomitant hip surgery, posttraumatic or pediatric deformities, or combined dysplasia and retroversion (90 patients, 95 hips). Dysplasia was defined as a lateral center-edge angle <23°; retroversion was defined by simultaneous appearance of a retroversion index 30% and positive ischial spine and posterior wall signs. Anteroposterior pelvic radiographs were taken in the supine position preoperatively, during PAO, postoperatively, and at short- and middle-term follow-up (mean ± SD [range]; 9 ± 3 weeks [5-23 weeks] and 21 ± 21 weeks [6-125 months]). The PS-SI ratio was calculated at 5 observation periods (preoperatively to middle-term follow-up) for different subgroups (dysplasia vs retroversion, uni- vs bilateral surgery, male vs female) and validated with intra- and interobserver agreement (intraclass correlation coefficients, 0.984 (95%CI, 0.976-0.989) and 0.991 (95% CI, 0.987-0.994), respectively). RESULTS: The PS-SI ratio differed between dysplasia and retroversion at all observation periods (P = .041 to P < .001). Male dysplastic hips had a lower PS-SI ratio when compared with female dysplastic hips at all observation periods (P < .001 to P = .005). In hips with acetabular retroversion, the PS-SI ratio was lower in men than women at short- and middle-term follow-up (P = .024 and .003). No difference was found between uni- and bilateral surgery (P = .306 to P = .905) except for short-term follow-up in dysplasia (P = .040). The PS-SI ratio decreased in all subgroups preoperatively to intra- or postoperatively (P < .001 to P = .031). At short- and middle-term follow-up, the PS-SI ratio increased as compared with intraoperatively (P < .001 to P = .044) and did not differ from preoperatively in all subgroups (P = .370 to P = .795). CONCLUSION: A lower PS-SI ratio was found for male or dysplastic hips. In all subgroups, the PS-SI ratio decreased during surgery, indicating retrotilt of the pelvis. Correct pelvic orientation during surgery is crucial for accurate acetabular reorientation. Retrotilt during surgery results in underestimation of acetabular version and iatrogenic retroversion of the acetabulum at follow-up, with the pelvis in the correct and more forward-tilted orientation. Not taking into account retrotilt during PAO potentially results in femoroacetabular impingement. Therefore, we changed our intraoperative setting with adjustment of the central beam to compensate for retrotilt of the pelvis.

Surgical hip dislocation with relative femoral neck lengthening and retinacular soft-tissue flap for sequela of Legg-Calve-Perthes disease.

OBJECTIVE: Correction of post-LCP (Legg-Calve-Perthes) morphology using surgical hip dislocation with retinacular flap and relative femoral neck lengthening for impingent correction reduces the risk of early arthritis and improves the survival of the native hip joint. INDICATIONS: Typical post-LCP deformity with external and internal hip impingement due to aspherical enlarged femoral head and shortened femoral neck with high riding trochanter major without advanced osteoarthritis (Tönnis classification ≤ 1) in the younger patient (age < 50 years). CONTRAINDICATIONS: Advanced global osteoarthritis (Tönnis classification ≥ 2). SURGICAL TECHNIQUE: By performing surgical hip dislocation, full access to the hip joint is gained which allows intra-articular corrections like cartilage and labral repair. Relative femoral neck lengthening involves osteotomy and distalization of the greater trochanter with reduction of the base of the femoral neck, while maintaining vascular perfusion of the femoral head by creation of a retinacular soft-tissue flap. POSTOPERATIVE MANAGEMENT: Immediate postoperative mobilization on a passive motion device to prevent capsular adhesions. Patients mobilized with partial weight bearing of 15 kg with the use of crutches for at least 8 weeks. RESULTS: In all, 81 hips with symptomatic deformity of the femoral head after healed LCP disease were treated with surgical hip dislocation and offset correction between 1997 and 2020. The mean age at operation was 23 years; mean follow-up was 9 years; 11 hips were converted to total hip arthroplasty and 1 patient died 1 year after the operation. The other 67 hips showed no or minor progression of arthrosis. Complications were 2 subluxations due to instability and 1 pseudarthrosis of the lesser trochanter; no hip developed avascular necrosis.

A Bibliometric Analysis of Fragility Fractures: Top 50.

Background and Objectives: The population is aging and fragility fractures are a research topic of steadily growing importance. Therefore, a systematic bibliometric review was performed to identify the 50 most cited articles in the field of fragility fractures analyzing their qualities and characteristics. Materials and Methods: From the Core Collection database in the Thomson Reuters Web of Knowledge, the most influential original articles with reference to fragility fractures were identified in February 2021 using a multistep approach. Year of publication, total number of citations, average number of citations per year since year of publication, affiliation of first and senior author, geographic origin of study population, keywords, and level of evidence were of interest. Results: Articles were published in 26 different journals between 1997 and 2020. The number of total citations per article ranged from 12 to 129 citations. In the majority of publications, orthopedic surgeons and traumatologists (66%) accounted for the first authorship, articles mostly originated from Europe (58%) and the keyword mostly used was "hip fracture". In total, 38% of the articles were therapeutic studies level III followed by prognostic studies level I. Only two therapeutic studies with level I could be identified. Conclusions: This bibliometric review shows the growing interest in fragility fractures and raises awareness that more high quality and interdisciplinary studies are needed.

Application of the reversed LISS-DF technique in an elderly patient to salvage infection-related failure of trochanteric fracture fixation.

Failure of cephalomedullary fixation in geriatric trochanteric fractures is a potential complication. Attempts have been made to optimize the implant fixation (e. g. cement augmentation) and several factors (e. g. malreduction, tip apex distance) have been identified as risk factors for failure. Nevertheless, if intramedullary fixation fails, it is often associated with bone defects in mostly preexisting poor bone-stock. Accordingly, conversion to total hip arthroplasty (THA) is recommended by some authors as the only valid treatment option. However, in specific situations (e. g. implant associated infection) conversion to THA might be less reasonable than an attempt to re-osteosynthesis. This article reports on the successful use of a reversed contralateral LISS-DF (LISS for the distal femur, DePuy Synthes, Zuchwil, Switzerland) application after failed cephalomedullary fixation and failed re-osteosynthesis using a blade plate in a trochanteric fracture in an elderly patient with additional implant associated infection.

Acetabular Cartilage Thickness Differs Among Cam, Pincer, or Mixed-Type Femoroacetabular Impingement: A Descriptive Study Using In Vivo Ultrasonic Measurements During Surgical Hip Dislocation.

OBJECTIVE: To investigate acetabular cartilage thickness among (1) 8 measurement locations on the lunate surface and (2) different types of femoroacetabular impingement (FAI). DESIGN: Prospective descriptive study comparing in vivo measured acetabular cartilage thickness using a validated ultrasonic device during surgical hip dislocation in 50 hips. Measurement locations included the anterior/posterior horn and 3 locations on each peripheral and central aspect of the acetabulum. The clock system was used for orientation. Thickness was compared among cam (11 hips), pincer (8 hips), and mixed-type (31 hips) of FAI. Mean age was 31 ± 8 (range, 18-49) years. Hips with no degenerative changes were included (Tönnis stage = 0). RESULTS: Acetabular cartilage thickness ranged from 1.7 mm to 2.7 mm and differed among the 8 locations (P < 0.001). Thicker cartilage was found on the peripheral aspect at 11 and 1 o'clock positions (mean of 2.4 mm and 2.7 mm, respectively). At 5 out of 8 locations of measurement (anterior and posterior horn, 1 o'clock peripheral, 12 and 2 o'clock central), cartilage thickness was thinner in hips with pincer impingement compared to cam and/or mixed-type of FAI (P ranging from <0.001 to 0.031). No difference in thickness existed between cam and mixed-type of impingement (P = 0.751). CONCLUSION: Acetabular cartilage thickness varied topographically and among FAI types. This study provides first baseline information about topographical cartilage thickness in FAI measured in vivo. Thinner cartilage thickness in pincer deformities could be misinterpreted as joint degeneration and could therefore have an impact on indication for hip preserving surgery.

The use of the E-PASS scoring system in determining complication development in patients with isolated acetabular fractures.

BACKGROUND: The decision to treat acetabular fractures is occasionally deferred or foregone in patients perceived to be unfit for surgery. The previously validated estimation of physiologic ability and surgical stress (E-PASS) score has been shown to predict outcome in a variety of fractures, and consists of a preoperative risk score (PRS), a surgical stress score (SSS), and a comprehensive risk score (CRS). PURPOSE: To correlate E-PASS and its components with postoperative complication to quantify risk for individual surgical and patient factors in acetabular fracture management. METHODS: A retrospective review of patient records was performed for all patients with acetabular fractures surgically treated between January 2013 and June 2018 in a level 1 Trauma Centre. Patients with multiple injuries and/or malignancies were excluded. E-PASS scores were determined with standard demographic data and subscores were correlated with complication development. RESULTS: Of the included 106 patients (mean age 61 years, range 17-93), complications were reported in 37 (34.9%) patients and 3 (2.8%) died. Hospital postoperative morbidity and mortality rates increased significantly with the PRS and CRS. The SSS did not correlate significantly with frequency of complications. Age was found to be the only significant independent risk factor (p value = 0.031, OR = 1.03 per year of age). CONCLUSION: Latent patient factors have a clear influence on adverse outcomes in contrast to controllable factors such as surgical stress indicating an important role for perioperative care in reducing postoperative complications. Integrated orthogeriatric care with assessment of comorbidities, prevention or early recognition, and treatment of perioperative complications is essential.

Comparison of the Primary Stability of Porous Tantalum and Titanium Acetabular Revision Constructs.

Adequate primary stability of the acetabular revision construct is necessary for long-term implant survival. The difference in primary stability between tantalum and titanium components is unclear. Six composite hemipelvises with an acetabular defect were implanted with a tantalum augment and cup, using cement fixation between cup and augment. Relative motion was measured at cup/bone, cup/augment and bone/augment interfaces at three load levels; the results were compared to the relative motion measured at the same interfaces of a titanium cup/augment construct of identical dimensions, also implanted into composite bone. The implants showed little relative motion at all load levels between the augment and cup. At the bone/augment and bone/cup interfaces the titanium implants showed less relative motion than tantalum at 30% load (p < 0.001), but more relative motion at 50% (p = n.s.) and 100% (p < 0001) load. The load did not have a significant effect at the augment/cup interface (p = 0.086); it did have a significant effect on relative motion of both implant materials at bone/cup and bone/augment interfaces (p < 0.001). All interfaces of both constructs displayed relative motion that should permit osseointegration. Tantalum, however, may provide a greater degree of primary stability at higher loads than titanium. The clinical implication is yet to be seen.

Rehabilitation protocols in unstable trochanteric fractures treated with cephalomedullary nails in elderly: current practices and outcome.

BACKGROUND: Optimal rehabilitation treatment after surgery for fixation of unstable trochanteric fractures is challenging in elderly patients. PURPOSE: The objective of this study is to analyse the existing literature on available rehabilitation protocols with regards to permitting or restricting early weight bearing following fixation of unstable trochanteric fractures treated by the use of cephalomedullary nails in patients at least 65 years of age. METHODS: A systematic review was performed based on the checklist of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Studies published between 1948 and 2018 on elderly patients with unstable trochanteric fractures treated with cephalomedullary nails that offered information on the postoperative rehabilitation protocol have been selected. Subsequently, the results and complications have been analysed according to the protocols. RESULTS: Fifteen of the 7056 initial articles have been selected for analysis. Authors who did not restrict weight bearing to their patients reported a shorter hospitalization time and a lower orthopaedic complication rate but a greater systemic complication rate, worse functional scores, and a higher reoperation and mortality rates. Those results should be taken with caution because of the heterogeneity of provided clinical information and the fact that none of the included studies considered the different rehabilitation protocols as study variables to analyse its influence on the results. CONCLUSION: With evidence available to date, there is no clear agreement on the postoperative rehabilitation protocol following fixation of an unstable trochanteric fracture by cephalomedullary nail in the elderly.

Femoral osteotomies for the treatment of avascular necrosis of the femoral head.

OBJECTIVE: Unloading of the area of necrosis out of the weight-bearing region by shifting healthy bone in the main weight-bearing area, which may delay the progression of the necrosis and enable healing. INDICATIONS: Circumscribed osteonecrosis of the femoral head without advanced degenerative signs (Tönnis grade ≤ 1) in the relatively young patient (age < 50 years). CONTRAINDICATIONS: Radiographic joint degeneration (> Tönnis grade 1); extensive avascular necrosis (Kerboul angle > 240°); advanced lesions (≥ Association Research Circulation Osseous [ARCO] classification 3b). SURGICAL TECHNIQUE: By performing a surgical hip dislocation, full access to the hip joint is gained. A femoral varus osteotomy is used to turn the necrotic lesion of the femoral head out of the central weight-bearing area and more medially. Osteosynthesis is performed with an angular stable screw or a blade plate. Via a trapdoor procedure, direct debridement and autologous bone grafting from the trochanter major is possible. The cartilage flap is preserved whenever possible or supplanted by an autologous matrix-induced chondrogenesis (AMIC). POSTOPERATIVE MANAGEMENT: A passive motion device is installed during hospital stay beginning immediately after surgery to prevent capsular adhesions. After surgery, patients are mobilized with partial weight-bearing of 15 kg with the use of crutches for at least 8 weeks. Forced abduction and adduction as well as flexion of more than 90° are restricted to protect the trochanteric osteotomy. After radiographic confirmation of healing at the 8­week follow-up, stepwise return to full weight-bearing is allowed and abductor training is initiated. RESULTS: Nine patients (10 hips) with osteonecrosis of the femoral head were treated with surgical hip dislocation and varus osteotomy. Six hips were treated with autologous bone grafting, four hips with antegrade drilling. Chondral lesions were sutured in four cases, whereas two cases needed an AMIC treatment. The mean age at operation was 29 ± 9 years (20-49), and the mean follow-up time for all patients was 3 ± 2 years (1-7). Conversion to a total hip prosthesis was required for one hip with progressing arthrosis. The other nine hips showed no progression of necrosis and an improved clinical outcome. Complications were pseudarthrosis of the femoral osteotomy and pseudarthrosis of the greater trochanter.

The pararectus approach-a versatile option in pelvic musculoskeletal tumor surgery.

BACKGROUND: Pelvic tumors are usually resected through the utilitarian pelvic incision, an extended ilioinguinal/iliofemoral approach. The pararectus approach, an intrapelvic anatomical approach with extraperitoneal access to the pelvis, has been established previously for the treatment of pelvic and acetabular fractures. However, it has not been used to address pelvic tumors. The study aimed at investigating the feasibility of this approach for pelvic tumor surgery and the possibilities of combining this approach with standard approaches to the hip joint. METHODS: Thirteen patients that underwent pelvic tumor resections were retrospectively reviewed. Tumor resections were performed through the pararectus (n = 10) or extended pararectus approach (n = 3). In six of those cases, the pararectus approach was combined with extrapelvic approaches including the modified Gibson (n = 4), the Kocher-Langenbeck (n = 1), and the trochanteric flip approach (n = 1). The mean follow-up was 32.6 ± 9.1 months. RESULTS: In all cases, the tumor resections were carried out according to the preoperative plan. In seven of 13 cases, wide resections were performed; six of 13 cases were planned close resections. Four cases of major complications were observed (vascular injury, deep infection, iliac vein thrombosis, total hip arthroplasty dislocation). Minor complications were observed in two cases. One tumor recurred locally. At the final follow-up, 10 patients were alive, eight of those without evidence of disease. CONCLUSION: The study demonstrated the suitability of the pararectus approach for pelvic tumor resections. The possibility to combine the approach with standard approaches to the hip joint allowed for single-stage reconstructions of the pelvis and the hip joint without sacrificing surgical margins and function. The pararectus approach is a versatile option adding to the established approaches for musculoskeletal tumor surgery of the pelvis.

[Femoroacetabular Impingement - Current Understanding]. / Femoroazetabuläres Impingement ­ aktuelles Verständnis.

Femoroacetabular impingement (FAI) is a painful and early contact between the proximal femur and the acetabular rim or the pelvis. The pathological bony abutment typically leads to a characteristic pattern of chondrolabral damage and is one of the main reasons for development of early osteoarthritis in the young hip joint. Classically, FAI was described as an intraarticular problem but the extraarticular impingement has recently gained in importance. This article provides an overview of the concept of FAI, the clinical presentation, the radiological assessment including its coxometric parameters and the treatment options currently available.

Surgical Hip Dislocation for Exposure of the Posterior Column.

BACKGROUND: Surgical hip dislocation is performed for safe and efficient management of acetabular fractures predominantly involving the posterior column. The dislocation of the femoral head allows for direct visualization of the hip joint during fracture treatment. DESCRIPTION: The patient is placed in the lateral decubitus position with sterile preparation and draping of the ipsilateral leg to allow for dislocation. The skin incision is straight and centered over the greater trochanter. After the skin incision, the interval between the gluteus maximus and medius muscles is developed. The sciatic nerve is identified, and special attention to the course of the medial circumflex femoral artery is given during dissection of the piriformis and triceps coxae muscles (obturator internus and superior and inferior gemelli muscles). The latter are incised 2 cm posterior to their insertion on the posterior aspect of the greater trochanter. The vastus lateralis muscle belly is elevated from the lateral femoral shaft, and a trochanteric osteotomy is performed. The trochanteric medallion is rotated 90°, and the gluteus minimus muscle is released from the capsule. After complete exposure of the hip capsule, a z-shaped capsulotomy is performed whereby any injury to the posterior capsular attachments of a posterior wall fragment is avoided. The posterior column and the greater and lesser sciatic notches are exposed, with the sciatic nerve under protection. The femoral head is dislocated either anteriorly or posteriorly to obtain direct visualization of the hip. Reduction begins at the articular surface, in cases of marginal impaction, and proceeds to the posterior wall and/or posterior column and the anterior column, when involved. For fixation, 3.5-mm cortical screws acting as positioning or lag screws and reconstruction plates are used. The capsule is sutured, the trochanteric fragment is reduced anatomically and stabilized with two 3.5-mm cortical screws, the piriformis and triceps coxae muscles are sutured, and a layered closure is performed. ALTERNATIVES: The Kocher-Langenbeck approach might be used instead. RATIONALE: Surgical hip dislocation facilitates assessment of cartilage damage at the acetabulum, marginal impaction, labral tears and femoral head lesions, removal or reinsertion of free intra-articular fracture fragments, direct visualization of the accuracy of reduction, and verification of extra-articular screw placement.

Open Reduction and Internal Fixation of Acetabular Fractures Using the Modified Stoppa Approach.

BACKGROUND: The modified Stoppa approach is performed for safe and efficient management of acetabular fractures involving the anterior column. This approach avoids dissection of the inguinal canal, the femoral nerve, and the external iliac vessels as seen in the "second window" of the ilioinguinal approach and has thus been shown to be less invasive than the ilioinguinal approach1. As an intrapelvic approach, it facilitates the management of medial displacement fracture patterns involving the quadrilateral plate and dome impaction that typically occur in the elderly2,3. The reduced morbidity of this approach is of particular relevance for elderly patients who must respond to the stresses of injury and surgery with diminished physiological reserves. DESCRIPTION: The specific surgical steps include preoperative planning, patient positioning and setup, a Pfannenstiel incision, superficial and deep dissection, development of the Retzius space and retraction of the bladder, exposure of the superior pubic ramus and iliopectineal eminence, dissection and ligation of a potential corona mortis, exposure of the obturator nerve and vessels, subperiosteal preparation of the pubic ramus with retraction of the external iliac vessels, subperiosteal exposure of the quadrilateral plate with detachment of the internal obturator muscle and exposure of the posterior column, assessment of residual displacement by fluoroscopic views, longitudinal soft-tissue or lateral skeletal traction (optional) for reduction of medial displacement of the femoral head, disimpaction of the acetabular dome fragment and grafting of the supra-acetabular void (optional) under fluoroscopic and arthroscopic (optional) control, and reduction and fixation of extra-articular components (iliac wing posteriorly and pubic ramus anteriorly), the posterior column (infra-acetabular screw), and the quadrilateral plate (buttress plate). Before wound closure, the urine output is checked for occurrence of hematuria, an indication of bladder penetration. The anterior lamina of the rectus sheath is then sutured, and a layered closure performed. ALTERNATIVES: The ilioinguinal approach might be used instead. RATIONALE: The modified Stoppa approach avoids dissection within the inguinal canal, the second window of the ilioinguinal approach. Therefore, this approach is less invasive and might be an alternative for joint-preserving surgery, especially in the elderly.

The Pararectus Approach: A New Concept.

BACKGROUND: Even 50 years after the introduction of the extrapelvic ilioinguinal approach for open reduction and internal fixation of acetabular fractures involving predominantly the anterior column, this approach is still acknowledged as being the so-called gold standard1. The pattern of acetabular fractures has changed within the last 10 to 20 years2,3, with a greater prevalence of quadrilateral plate fractures that is due in part to the increase in elderly trauma. The intrapelvic approach, also called the modified Stoppa approach4-6, was introduced as a less invasive alternative to the extrapelvic ilioinguinal approach, mostly combined with the first window of the ilioinguinal approach. The Pararectus approach also offers intrapelvic surgical access and has demonstrated safe surgical dissection with enhanced exposure and favorable outcome compared with the Stoppa approach7-10. DESCRIPTION: The skin incision runs along the lateral border of the rectus abdominis muscle to develop the anterior rectus sheath. The retroperitoneal space lateral to the rectus abdominis muscle is entered and the inferior epigastric vessels and the round ligament in females or the spermatic cord in males are identified. The superior pubic ramus and the iliopectineal eminence are exposed. If the corona mortis vessels (a vascular anastomosis between the obturator vessels and the external iliac artery) are present, they are ligated. The obturator nerve and vessels are exposed. The dissection is then directed posteriorly under retraction of the external iliac vessels with further subperiosteal exposure of the pubic ramus, the quadrilateral plate, and the posterior column. Any nonessential iliolumbar vessels are ligated. Residual displacement is assessed with fluoroscopic views. For reduction of a medially displaced femoral head, longitudinal extremity soft tissue or lateral skeletal traction (optional), with a Schanz pin in the greater trochanter, is used. For disimpaction of acetabular dome fragments and grafting of a supra-acetabular void (optional), a fluoroscopy unit is used to assess reduction and identify the void; in addition, arthroscopy can be used. The scope is introduced through the fracture gap to check for reduction without any water or specific setup. For reduction and fixation of extra-articular components (iliac wing posteriorly and superior pubic ramus anteriorly), the posterior column, and the quadrilateral plate, the fluoroscopy unit is used. The anterior lamina of the rectus sheath is sutured, and a layered closure performed. ALTERNATIVES: The ilioinguinal or modified Stoppa approach might be used instead. RATIONALE: The Pararectus approach combines the advantages of the ilioinguinal approach and the Stoppa approach. The Pararectus approach facilitates surgical access directly above the hip joint, which is comparable with the access obtained through the second window of the ilioinguinal approach, but without dissection of the inguinal canal. Moreover, the Pararectus approach provides intrapelvic visualization that is at least equivalent to that offered by the Stoppa approach but without losing any direct access to the hip joint.

Comparison of Fixation Techniques for Acetabular Fractures Involving the Anterior Column with Disruption of the Quadrilateral Plate: A Biomechanical Study.

BACKGROUND: In elderly patients who have sustained an acetabular fracture involving disruption of the quadrilateral plate (QLP), postoperative loading of the joint beyond the level of partial weight-bearing can result in medial redisplacement of the QLP. The purpose of this biomechanical study was to compare the performances of 4 different fixation constructs intended to prevent medial redisplacement of the QLP. METHODS: Anterior column posterior hemitransverse (ACPHT) fractures with disruption of the QLP were created on synthetic hemipelves (fourth-generation Sawbones models) and subsequently stabilized with (1) a 12-hole plate bridging the QLP (Group 1), (2) the plate with added periarticular screws along the QLP (Group 2), (3) the plate combined with an infrapectineal buttress plate (Group 3), or (4) the plate with the added periarticular screws as well as the buttress plate (Group 4). The point of load application on the acetabulum was defined to be the same as the point of application of maximum vertical hip contact force during normal walking. Loads were applied to simulate either partial weight-bearing (20 cycles, from 35 to 350 N) or inadvertent supraphysiologic loads (linearly increasing loads until the onset of failure, defined as fragment displacement of >3 mm). A universal testing machine was synchronized with a digital image correlation system to optically track redisplacement at the QLP. The level of significance was set at p < 0.05. RESULTS: During experimental simulation of partial weight-bearing, maximum fracture step openings never exceeded 2 mm. During simulation of inadvertent supraphysiologic load, the median load to failure was higher (p < 0.05) in Group 2 (962 N; range, 798 to 1,000 N) and Group 4 (985 N; range, 887 to 1,000 N) compared with Group 1 (445 N; range, 377 to 583 N) and Group 3 (671 N; range, 447 to 720 N). CONCLUSIONS: All 4 fixation constructs performed in an acceptable manner on testing with simulated partial weight-bearing. Only additional periarticular screws along the QLP increased the fixation strength. CLINICAL RELEVANCE: Redisplacement of the QLP resulting in an incongruency of the hip joint has been associated with poor long-term outcomes. Within the constraints of this study, periarticular long screws were superior to infrapectineal buttress plates in preventing medial redisplacement of the QLP.

One-third of Hips After Periacetabular Osteotomy Survive 30 Years With Good Clinical Results, No Progression of Arthritis, or Conversion to THA.

BACKGROUND: Since its first description in 1984, periacetabular osteotomy (PAO) has become an accepted treatment for hip dysplasia. The 30-year survivorship with this procedure has not been reported. Because these patients are often very young at the time of surgery, long-term followup and identification of factors associated with poor outcome could help to improve patient selection. QUESTIONS/PURPOSES: Looking at the initial group of patients with hip dysplasia undergoing PAO at the originator's institution, we asked: (1) What is the cumulative 30-year survival rate free from conversion to THA, radiographic progression of osteoarthritis, and/or a Merle d'Aubigné-Postel score < 15? (2) Did hip function improve and pain decrease? (3) Did radiographic osteoarthritis progress? (4) What are the factors associated with one or more of the three endpoints: THA, radiographic progression of osteoarthritis, and/or Merle d'Aubigné-Postel score < 15? METHODS: We retrospectively evaluated the first 63 patients (75 hips) who underwent PAO for hip dysplasia between 1984 and 1987. At that time, hip dysplasia was the only indication for PAO and no patients with acetabular retroversion, the second indication for a PAO performed today, were included. During that period, no other surgical treatment for hip dysplasia in patients with closed triradiate cartilage was performed. Advanced osteoarthritis (≥ Grade 2 according to Tönnis) was present preoperatively in 18 hips (24%) and 22 patients (23 hips [31%]) had previous femoral and/or acetabular surgery. Thirty-nine patients (42 hips [56%]) were converted to a THA and one patient (one hip [1%]) had hip fusion at latest followup. Two patients (three hips [4%]) died from a cause unrelated to surgery 6 and 16 years after surgery with an uneventful followup. From the remaining 21 patients (29 hips), the mean followup was 29 years (range, 27-32 years). Of those, five patients (six hips [8%]) did not return for the most recent followup and only a questionnaire was available. The cumulative survivorship of the hip according to Kaplan-Meier was calculated if any of the three endpoints, including conversion to THA, progression of osteoarthritis by at least one grade according to Tönnis, and/or a Merle d'Aubigné-Postel score < 15, occurred. Hip pain and function were assessed with Merle d'Aubigné-Postel score, Harris hip score, limp, and anterior and posterior impingement tests. Progression of radiographic osteoarthritis was assessed with Tönnis grades. A Cox regression model was used to calculate factors associated with the previously defined endpoints. RESULTS: The cumulative survivorship free from conversion to THA, radiographic progression of osteoarthritis, and/or Merle d'Aubigné-Postel score < 15 was 29% (95% confidence interval, 17%-42%) at 30 years. No improvement was found for either the Merle d'Aubigné-Postel (15 ± 2 versus 16 ± 2, p = 0.144) or Harris hip score (83 ± 11 versus 85 ± 17, p = 0.602). The percentage of a positive anterior impingement test (39% versus 14%, p = 0.005) decreased at 30-year followup, whereas the percentage of a positive posterior impingement test (14% versus 3%, p = 0.592) did not decrease. The percentage of positive limp decreased from preoperatively 66% to 18% at 30-year followup (p < 0.001). Mean osteoarthritis grade (Tönnis) increased from preoperatively 0.8 ± 1 (0-3) to 2.1 ± 1 (0-3) at 30-year followup (p < 0.001). Ten factors associated with poor outcome defined as THA, radiographic progression of osteoarthritis, and/or Merle d'Aubigné-Postel score < 15 were found: preoperative age > 40 years (hazard ratio [HR] 4.3 [3.7-4.9]), a preoperative Merle d'Aubigné-Postel score < 15 (HR 4.1 [3.5-4.6]), a preoperative Harris hip score < 70 (HR 5.8 [5.2-6.4]), preoperative limp (HR 1.7 [1.4-1.9]), presence of a preoperative positive anterior impingement test (HR 3.6 [3.1-4.2]), presence of a preoperative positive posterior impingement test (HR 2.5 [1.7-3.2]), a preoperative internal rotation of < 20° (HR 4.3 [3.7-4.9]), a preoperative Tönnis Grade > 1 (HR 5.7 [5.0-6.4]), a postoperative anterior coverage > 27% (HR 3.2 [2.5-3.9]), and a postoperative acetabular retroversion (HR 4.8 [3.4-6.3]). CONCLUSIONS: Thirty years postoperatively, 29% of hips undergoing PAO for hip dysplasia can be preserved, but more than 70% will develop progressive osteoarthritis, pain, and/or undergo THA. Periacetabular osteotomy is an effective technique to treat symptomatic hip dysplasia in selected and young patients with closed triradiate cartilage. Hips with advanced joint degeneration (osteoarthritis Tönnis Grade ≥ 2) should not be treated with PAO. Postoperative anterior acetabular overcoverage or postoperative acetabular retroversion were associated with decreased joint survival. LEVEL OF EVIDENCE: Level III, therapeutic study.

Evaluation of Constant Thickness Cartilage Models vs. Patient Specific Cartilage Models for an Optimized Computer-Assisted Planning of Periacetabular Osteotomy.

Modern computerized planning tools for periacetabular osteotomy (PAO) use either morphology-based or biomechanics-based methods. The latter relies on estimation of peak contact pressures and contact areas using either patient specific or constant thickness cartilage models. We performed a finite element analysis investigating the optimal reorientation of the acetabulum in PAO surgery based on simulated joint contact pressures and contact areas using patient specific cartilage model. Furthermore we investigated the influences of using patient specific cartilage model or constant thickness cartilage model on the biomechanical simulation results. Ten specimens with hip dysplasia were used in this study. Image data were available from CT arthrography studies. Bone models were reconstructed. Mesh models for the patient specific cartilage were defined and subsequently loaded under previously reported boundary and loading conditions. Peak contact pressures and contact areas were estimated in the original position. Afterwards we used a validated preoperative planning software to change the acetabular inclination by an increment of 5° and measured the lateral center edge angle (LCE) at each reorientation position. The position with the largest contact area and the lowest peak contact pressure was defined as the optimal position. In order to investigate the influence of using patient specific cartilage model or constant thickness cartilage model on the biomechanical simulation results, the same procedure was repeated with the same bone models but with a cartilage mesh of constant thickness. Comparison of the peak contact pressures and the contact areas between these two different cartilage models showed that good correlation between these two cartilage models for peak contact pressures (r = 0.634 ∈ [0.6, 0.8], p < 0.001) and contact areas (r = 0.872 > 0.8, p < 0.001). For both cartilage models, the largest contact areas and the lowest peak pressures were found at the same position. Our study is the first study comparing peak contact pressures and contact areas between patient specific and constant thickness cartilage models during PAO planning. Good correlation for these two models was detected. Computer assisted planning with FE modeling using constant thickness cartilage models might be a promising PAO planning tool when a conventional CT is available.