Changes in load-bearing area after Ganz periacetabular osteotomy

Background and purpose?Implant dislocation is one of the commonest complications following primary total hip replacement (THR). We investigated the effect of body mass index (BMI) and tobacco use on the risk of this complication.

Subjects and methods?Through linkage between the Swedish Construction Workers’ cohort and the Swedish Inpatient Register, 2,106 male patients who had undergone primary THR between 1997 and 2004 were identified. We used Cox multivariable regression analysis to study the association between BMI and tobacco use and the risk of implant dislocation.

Results?53 patients (2.5%) developed implant dislocation during a mean of 2 (0–3) years of follow-up. We found overweight and obesity to be associated with increased risk of implant dislocation (HR = 2.5,95% CI: 1.1–5.5 and HR = 3.7, 95% CI: 1.5–9.3, respectively as compared to those of normal weight). There was no statistically significant association between tobacco use and the risk of dislocation.

Interpretation?Greater attention should be given to high BMI as a risk factor for implant dislocation following THR.     

The natural history of the periacetabular fragment following Ganz osteotomy

The vascularity of the acetabular free fragment in Ganz osteotomies has remained a concern. This study aims to assess the role of MR imaging in the postoperative evaluation of Ganz osteotomies. Twenty patients (19 females, 1 male), average age 24 years (range, 12-36 years), had sequential magnetic resonance imaging studies of the pelvis at 6 weeks and 6 months following Ganz osteotomies. Normal healing with no evidence of periosteotomy edema was seen in 17 patients at 6 weeks. Three patients showed evidence of reduced vascularity. In two of these, there were focal changes suggestive of subclinical ischemia. The other had gross signal changes in the osteotomy fragment suggestive of diffuse ischemia. The patients with focal changes were asymptomatic and had normal 6-month scans. The patient with diffuse changes complained of persistent groin pain, which resolved after 4 months. The 6-month scan showed some persistent vascular changes. The scan at 1 year showed complete resolution. The study suggests that Ganz osteotomy has minimal effect on the vascularity of the acetabular free fragment.     

Changes in load-bearing area after Ganz periacetabular osteotomy evaluated by multislice CT scanning and stereology

BACKGROUND: We used a stereologic method based on 3D CT scanning to estimate the projected load-bearing surface in the hip joint. PATIENTS AND METHODS: 6 normal hip joints and 6 dysplastic hips were examined. The latter were CT-scanned before and after periacetabular osteotomy. RESULTS: We found that the average area of the projected load-bearing surface of the femoral head preoperatively was 7.4 (6.5-8.4) cm2 and postoperatively 11 (9.8-14) cm2, which was similar to the load-bearing surface in the normal control group. We performed double measurements and the coefficient of error of the mean was estimated at 1.6%. Due to overprojection, an overestimation of about 3.8% on the projected load-bearing surface occurred. Consequently, the stereologic method proved to be precise and unbiased. INTERPRETATION: Our findings indicate that this method is of value for monitoring the load-bearing area in the hip joint of patients undergoing periacetabular osteotomy.     

Comparison of two methods of screw fixation in periacetabular osteotomy

The optimal method of fixation during periacetabular osteotomy is unknown. Periacetabular osteotomies were created on both sides of six whole pelves from fresh cadavers and were fixed randomly either with three long 4.5-mm cortical screws from the iliac crest to the osteotomized fragment (iliac fixation) or with two such screws supplemented by a transverse screw from the acetabular segment to the ilium (transverse fixation). Pelvis loading in simulated push-off phase of the gait cycle was accomplished using a custom-made fixture. Linear potentiometers measured displacements at the pubic and ischial osteotomies. Fracture site stiffness was calculated from actuator force and pubic osteotomy displacement data. Displacement of the pubic osteotomy averaged 12.8 mm in the iliac fixation group and average 12.45 mm in the transverse group fixation. The ultimate loads beyond which catastrophic failure occurred were measured from 531.27 N to 1103.3 N (mean, 741.5 N) and 660.9 N to 1273.9 N (mean, 930.8 N), respectively. Effective stiffness ranged from 38.9 N/mm to 117 N/mm in the iliac fixation group (mean, 77.8 N/mm), and from 99 N/mm to 315 N/mm in the transverse construct (mean, 182 N/mm). Although the transverse screw provided statistically significantly greater local stiffness to the periacetabular construct fixation, neither type of fixation provided enough stability to allow immediate weightbearing after periacetabular osteotomy.     

Evaluation of acetabular versions after a curved periacetabular osteotomy for dysplastic hips

The purpose of this study is to investigate the early clinical and radiographic findings related to acetabular orientation after a curved periacetabular osteotomy (CPO). 106 dysplastic hips of 88 patients underwent CPO were investigated retrospectively with an average follow-up of 3.6 years. Conventional anteroposterior radiographs were used to measure the radiographic findings and range of motion were used for clinical evaluations. A significant improvement was noted in radiographic measurements including lateral centre-edge angle, acetabular index, and acetabular angle of Sharp. However, a high rate of postoperative acetabular retroversion was observed (62% hips) and a marked decrease in free flexion was noted. The Tönnis scale revealed a one-grade progression in most retroversion hips. Acetabular retroversion is a high risk factor leading to degenerative osteoarthritis of hip. Therefore, special consideration must be taken in surgical planning and careful intraoperative confirmation is required whilst manoeuvring the acetabular fragment in CPO.     

Late foreign-body reaction to PLLA screws used for fixation of acetabular osteotomy

A 31-year-old woman underwent rotational acetabular osteotomy for acetabular dysplasia. At surgery, the acetabular fragment and the grafted bone were fixed with PLLA screws. One year 7 months after surgery, the patient returned to our clinic with acute swelling and pain with sinus formation. Based on the diagnosis of an infection, local debridement was performed. Histological examination of the debrided tissue revealed inflammatory cells; however no organism was found growing on the bacterial culture. During subsequent attempts to drain the lesion, we found small PLLA particles. Thus, we diagnosed the condition as a continued inflammatory process due to foreign-body reaction to the fragmented screw material. After a repeat debridement, the inflammation subsided. At the final follow-up two years after the last procedure, there was no recurrence and the patient had returned to regular activities. This report represents the first case of a severe local reaction to PLLA implants at and around the major joints.     

Anterior femoro-acetabular impingement due to acetabular retroversion. Treatment with periacetabular osteotomy

BACKGROUND: This study was performed to evaluate whether symptomatic anterior femoro-acetabular impingement due to acetabular retroversion can be treated effectively with a periacetabular osteotomy. METHODS: The diagnosis of femoro-acetabular impingement was based on clinical symptoms, a positive anterior impingement test, and findings of acetabular rim lesions on magnetic resonance imaging. The radiographic diagnosis of acetabular retroversion was based on the cross-over and posterior wall signs. Twenty-nine hips in twenty-two patients (average age, twenty-three years) underwent a periacetabular osteotomy. An arthrotomy was performed in twenty-six hips in order to visualize intra-articular lesions and, in selected cases, to improve a low femoral head-neck offset. The range of motion of the hip was measured, clinical evaluation was performed with use of the score described by Merle d'Aubigné and Postel, and the anterior center-edge angle of Lequesne and de Sèze was measured on radiographs preoperatively and at the time of the latest follow-up. RESULTS: The duration of follow-up averaged thirty months (range, twenty-four to forty-nine months). The anterior center-edge angle of Lequesne and de Sèze decreased significantly from a preoperative average of 36 degrees (range, 26 degrees to 52 degrees ) to a postoperative average of 28 degrees (range, 16 degrees to 46 degrees ) (p = 0.002). There was a significant increase in the average range of internal rotation (10 degrees, p = 0.006), flexion (7 degrees, p = 0.014), and adduction (8 degrees, p = 0.017). The average Merle d'Aubigné score increased from 14.0 points (range, 12 to 16 points) preoperatively to 16.9 points (range, 15 to 18 points) postoperatively (p < 0.001), and the result was good or excellent for twenty-six hips. Three hips underwent subsequent surgery: one, because of early postoperative loss of reduction; one, for correction of posteroinferior impingement; and one, because of recurrent signs of anterior impingement. CONCLUSION: Periacetabular osteotomy is an effective way to reorient the acetabulum in young adults with symptomatic anterior femoro-acetabular impingement due to acetabular retroversion     

Press-fit cementless acetabular fixation with and without screws

Purpose

Cementless acetabular fixation for total hip arthroplasty (THA) is widely used. The question of using screws for a better primary and secondary acetabular fixation has been discussed in the literature in recent years. The aim of this meta-analysis was to compare fixation of acetabular cups with and without screws in total hip arthroplasty.

Methods

Electronic databases Embase, PubMed and Cochrane Library were used to search for randomised controlled trials reported through May 2013 of cementless acetabular fixation for THA with and without screws. Two independent reviewers assessed the trials for eligibility and quality. All related data matching our standards were abstracted for meta-analysis by RevMan 5.0. Evaluation criteria included revisions, migration and osteolysis.

Results

A total of 1,130 THAs enrolled into five trials were included in this meta-analysis. All studies compared fixation of acetabular cups with and without screws, and our pooled data showed no statistical significance between the two surgical methods in revision, migration and osteolysis.

Conclusion

There is no significant difference between cementless acetabular fixation for THA with and without screws in revisions, migration or osteolysis.     

Incisional hernia after periacetabular osteotomy

The incidence of incisional abdominal hernias, an unreported complication after a Bernese periacetabular osteotomy, was evaluated. Two cases of an incisional hernia above the iliac crest were detected in a series of 950 cases since 1984. Although the incidence has been small, risk factors may be obesity, weak abdominal muscle strength, or increased abdominal pressure attributable to chronic coughing or obstipation. The surgeon should recognize the importance of restoring continuity of the abdominal fascia in patients with such factors.     

Metatarsal osteotomy using internal fixation with compression screws

Forty-six metatarsal osteotomies in 25 feet were performed in order to treat forefoot deformity. The authors used an exacting operative procedure based on oblique osteotomies of the metatarsal and rigid internal fixation. All osteotomies healed and only one patient was not satisfied with the operation. This technique provided predictable long-term results in the authors' hands, and also involved an easier postoperative course than conventional methods.     

Anterior femoroacetabular impingement after periacetabular osteotomy.

As experience with the Bernese periacetabular osteotomy has grown, an unexpected observation in a group of patients has alerted the authors to the risk of a secondary impingement syndrome that may occur some time after the periacetabular osteotomy. This possibly may explain residual pain and limited range of motion in a larger group of patients. The impingement is produced by abutment of the femoral head or head to neck junction on the anterior rim of the properly aligned acetabulum. The symptoms are those of restricted flexion, and limited or absent internal rotation in flexion, with variable groin pain. Magnetic resonance imaging studies may reveal acetabular labral disease and adjacent cartilage damage associated with the impingement. Lack of anterior or anterolateral offset between the femoral neck and head results in neck to rim contact when the hip is flexed and/or internally rotated. Before the periacetabular osteotomy this is compensated by the lack of anterior acetabular coverage, but after proper correction the mismatch becomes apparent. The authors recently have devised a routine during the periacetabular osteotomy procedure whereby after the acetabular fragment is corrected into the desired position, the joint is opened, visually inspected, and palpated for impingement with the hip flexed and internally rotated. When necessary, a resection osteoplasty of the femoral neck to head junction is performed to improve the head and neck offset and reduce the anterior contact. This, in the short term, has provided satisfactory prevention of postoperative impingement.     

Rotational acetabular osteotomy using biodegradable internal fixation

We used biodegradable poly-l-lactide screws in rotational acetabular osteotomy in 41 hips of 41 patients, and studied the complications after an average follow-up of 4.9 years (range 1.0–7.7 years). There were 39 females and 2 males, their average age at the time of the operation was 32 years (range 12–55 years). A small subcutaneous abscess appeared around the non-absorbable sutures in 2 patients after surgery. There was 1 case of thrombophlebitis and 1 of local dermatitis. The small subcutaneous abscess resolved after the removal of the suture material in the 2 cases, and the thrombophlebitis resolved with aspirin. The local dermatitis persisted but was cured by local steroid therapy over 5.8 years. The incidence of local dermatitis after the use of biodegradable implants should be further investigated.

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Résumé Nous avons utilisé des vis biodégradables en poly L lactide pour les ostétomies acétabulaires rotatoires des 41 hanches de 41 patients et nous avons étudié les complications possibles sur un suivi moyen de 4.9 ans (de 1 à 7.7 ans). L’échantillon comportait 39 femmes et 2 hommes. L’age moyen au moment de l’opération était de 32 ans (12 à 55 ans). Nous avons noté 2 cas de complication post-opératoire sous la forme d’un petit abcès sous-cutané autour des sutures irrésorbables, 1 cas de thrombophlébite et 1 cas d’eczéma local. Le petit abcès souscutané s’est résorbé après enlèvement du matériau de suture dans les 2 cas, la thrombophlébite a été traiteé l’aspirine et l’eczéma local a été soigné par une thérapie locale aux stéroides en 5.8 ans. La fréquence des dermatites locales après l’utilisation des implants biodégradables devrait être étudiée sur un plus grand nombre de cas.

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Accepted: 20 October 1998     

Prevention of nerve injury after periacetabular osteotomy

Background  

The Bernese periacetabular osteotomy (PAO) is the preferred pelvic osteotomy in many centers treating symptomatic acetabular dysplasia in the young adult. Major nerve injury has been reported as a complication that can occur with this complex procedure, but the incidence and circumstances associated with such injury are not well known.     

Association between total hip arthroplasty following periacetabular osteotomy and acetabular component overhang

European Journal of Orthopaedic Surgery & Traumatology - There is limited understanding of anterior acetabular component overhang, which induces groin pain, in post-periacetabular osteotomy...     

Radiographic and magnetic resonance imaging findings of polylevolactic acid screws after rotational acetabular osteotomy

Introduction Biodegradable polylevolactic acid implants have become more commonly used for the treatment of fractures and osteotomies over the past few years. In the present study, the biocompatibility and degradation of polylevolactide screws used for rotational acetabular osteotomy were assessed on the basis of radiographic and MRI findings.Materials and methods Forty-nine hips of 47 patients were analyzed for this study. The average age of the patients at the time of surgery was 38.0 years (range 18–62 years). The original diagnosis was osteoarthritis in 43 hips and osteonecrosis in 6 hips. The mean duration of follow-up was 2.8 years (range 1.5–5.5 years). Anteroposterior radiographs obtained at 1 week, 6 months, 1 year after the operation, as well as the most recent radiographs, were used to assess bony union, the radiolucent tract of each screw, and the sclerotic rim around each screw. Fifteen patients were chosen randomly to undergo MRI.Results Union of the osteotomized surfaces occurred in all patients within 6 months of surgery. Radiographs showed no osteolysis, no formation of bone cysts, and no displacement of the osteotomized acetabulum in any of the 49 hips. None of the patients was found to have any complications caused by problems with the biocompatibility of the implants. At the final postoperative examination, a central radiolucent tract and a sclerotic rim around the screws were seen in 34/49 hips (69%) and 23/49 hips (47%), respectively. On MRI findings, we were able to detect significant resorption of the screws in two patients after 1.2 and 1.7 years of follow-up. Though localized low-intensity areas on T1-weighted images and high-intensity areas on T2-weighted images were observed at the top of the screws in 5 patients, there was no development of pain, tenderness, or a sinus during the follow-up period.Conclusion Although absorption of polylevolactic acid screws did not occur in a large majority of cases, rotational acetabular osteotomy appears to be a good indication for the use of polylevolactic acid screws.     

Effect of periacetabular osteotomy for acetabular dysplasia clarified by three-dimensional finite element analysis

Background  

Finite element analysis (FEA) has been applied for the biomechanical analysis of acetabular dysplasia, but not for biomechanical studies of periacetabular osteotomy (PAO) or those performing analysis taking into consideration the severity of acetabular dysplasia. This study aimed to perform biomechanical evaluation of changes in stress distribution following PAO and to determine the effect of the severity of developmental dysplasia of the hip (DDH) using three-dimensional FEA.     

经骨盆内髋臼周围截骨术治疗成人髋臼发育不良

目的介绍经髂腹股沟入路在骨盆内壁行伯尔尼髋臼周围截骨术治疗成人髋臼发育不良。方法1997年10月～2001年4月,共有51例患者(53髋)因髋臼发育不良造成髋关节疼痛而接受经髂腹股沟入路髋臼周围截骨术(Berneseperiacetabularosteotomy)。患者平均年龄30.6岁(13～48岁,其中1例13岁患者的髋臼骨骺已完全闭合),男∶女=1∶10。术前患者平均疼痛3.4年(3个月～15年);髋关节活动度正常或基本正常(235°～360°,平均300°)。术前X线片显示CE角?15°～15°,平均1.1°;臼顶倾斜角为15°～55°,平均28°;髋关节间隙正常或轻度狭窄。53%的髋关节伴有不同程度的半脱位(Shenton线不连续)。结果24例(24髋)有12～38个月(平均26个月)的随访结果。24髋术后疼痛明显减轻,髋关节活动度保持正常。Harris评分从术前平均79.8分(64～83分)提高到术后平均93.8分(75～100分)。术后CE角平均为40°(20°～60°),臼顶倾斜角平均为9°(0°～20°),Shenton线不连续率降为33%。术中及术后并发症包括股神经损伤1例,膀胱功能障碍1例,切口疝2例。结论骨盆内髋臼周围截骨术治疗成人髋臼发育不良可以获得良好疗效。该术式的特点为:在保持骨盆环和髋外展肌完整的基础上,可以最大限度地改善髋关节畸形,恢复髋关节的解剖关系。患者术后髋关节功能恢     

Complications and patient satisfaction after periacetabular pelvic osteotomy

Periacetabular osteotomy (PAO) is a well established method to treat hip dysplasia in the adult. There is, however, a lack of information on the subjective outcome of patients with complications after PAO. The purpose of this study was therefore to assess the influence of complications on the patients' post-operative wellbeing and function: 60 PAOs on 50 patients were investigated retrospectively after a mean follow-up of 7.4 years. The patients' self-reported assessment of health and function was evaluated by the Medical Outcomes Short Form-36 (SF-36) and the Western Ontario and McMaster Universities (WOMAC) questionnaires at last follow-up. Forty healthy persons served as a control group. Of the 60 interventions 13 had no complications. Minor complications occurred in 25 (41%) and in 22 (37%) at least one major complication occurred. SF-36 summary measure was 76.4 for PAO patients and 90.3 for the control group. Mean WOMAC score was 25.1. Patients with major complications had a similar subjective outcome as patients with minor or without complications, but persistent dysaesthesia due to lateral femoral cutaneous nerve dysfunction led to a worse subjective function. Lesions of the lateral femoral cutaneous nerve have much greater influence on patients' self-assessed functional outcome after PAO than previously reported and greater attention has to be given to this supposedly minor complication.