Evaluation of the biomechanics of the hip following a triple osteotomy of the innominate bone

Risk factors associated with non-union after triple pelvic osteotomy (Toennis and Kalchschmidt technique): a case-control study and review of the literature

INTRODUCTION

Dysplasia of the hip is a well known cause of secondary osteoarthritis of the hip. The triple pelvic osteotomy (TPO), according to the technique described by Toennis and Kalchschmidt, is a well established procedure to address dysplasia of the hip joint. Non-unions after triple pelvic osteotomies are rare and can occur at each of these osteotomies. The literature is lacking in studies investigating larger group of patients with non-unions after triple pelvic osteotomy. The aim of this study is to evaluate risk factors leading to a non-union after triple pelvic osteotomy.

METHODS

A total of 53 patients with a non-union after triple pelvic osteotomy were included in this retrospective case-control. In addition, we identified a cohort of randomly selected patients undergoing hardware removal after triple pelvic osteotomy ("union" group) but had not developed non-union as the control group. This control group underwent the same procedure by the same group of surgeons in the same time period. The variables obtained from the review of the two groups were analyzed using appropriate statistical methods including Bivariable Analysis (p < 0.005) and Multivariable logistic regression analysis (p < 0.015).

RESULTS

We identified a total of 53 patients out of the 3269 who had undergone TPO and had developed a non-union. The control group consisted of 117 patients who did not experience a non-union. Bivariable analysis of basic demographic characteristics demonstrated that gender, BMI, smoking, preoperative CE angle and degree of surgical correction did not differ significantly between the groups. There was a statistically significant (p < 0.05) difference between age (31.5 ± 9.4 vs. 27.5 ± 9.0 in the non-union and union groups, respectively; p = < 0.001) and postoperative CE angle (34.4 ± 5.0 vs. 32.8 ± 3.5 in the non-union and union groups, respectively; p = 0.02). Multivariable analysis demonstrated that an age over 30 was significantly associated with non-union (p = 0.01, OR 2.6, 95% CI 1.3-5.3).

CONCLUSION

Non-unions after TPO are rare. A higher age and higher degree of surgical correction might be associated risk factors for developing a non-union. Furthermore, smoking, obesity and previous hip surgeries might also contribute to developing a non-union after triple pelvic osteotomy.

Modified triple pelvic osteotomy for adult symptomatic acetabular dysplasia: clinical and radiographic results at midterm follow-up

Background

Acetabular dysplasia is the most common cause of secondary arthritis of the hip joint. Achieving maximum restoration of the acetabular coverage and medialization of the femoral head remains difficult with the original Steel triple pelvic osteotomy for acetabular dysplasia in children and adults. This study intended to answer the following questions: (1) Are the midterm functional results of our modified procedure favorable, particularly in relation to Harris scores? and (2) On the basis of the Tönnis grade, does this procedure has a different effect on radiographic parameters and functional results at midterm follow-up?

Methods

This study included 26 consecutive adult patients with symptomatic acetabular dysplasia (28 hips) who underwent modified triple pelvic osteotomy through two incisions between July 2005 and June 2012. According to the preoperative Tönnis grade, the patients were divided into T0 (Tönnis grade 0), T1 (Tönnis grade 1), and T2 (Tönnis grade 2) groups. Wiberg center-edge (CE) angle, Sharp acetabular angle, lateralization, and Harris scores were analyzed to assess the radiographic and clinical outcomes.

Results

The mean CE angle (28.43° [± 3.58°], p < 0.05), Sharp acetabular angle (36.39° [± 3.26°], p < 0.05), lateralization (16.82 mm [± 3.10 mm], p < 0.05), and Harris scores (89.07 [± 4.97], p < 0.05) at the last follow-up significantly improved compared to those preoperatively. Multiple comparisons of radiographic outcomes among the three groups indicated no significant difference (p < 0.05). Harris scores in group T2 were significantly lower than those in groups T0 (p < 0.05) and T1 (p < 0.05). No major complication was observed.

Conclusions

Our modified triple pelvic osteotomy for adult symptomatic acetabular dysplasia with early-stage osteoarthritis could lead to excellent radiographic outcomes, good clinical results, and lower complication rates.

Gait and lower limb muscle strength in women after triple innominate osteotomy

Background

In adult patients with developmental hip dysplasia, a surgical procedure (triple innominate osteotomy) of the pelvic bone can be performed to rotate the acetabulum in the frontal plane, establishing better acetabular coverage. Although common clinical hip scores demonstrate significant improvements after surgery, they provide only overall information about function. The purpose of this study was to quantify the long-term outcome of triple innominate osteotomy in more detail using gait analyses and muscle strength measurements.

Methods

We performed gait analyses at self-selected walking speed as well as isometric hip and knee muscle strength tests in twelve women who had undergone a unilateral triple innominate osteotomy (age: 34 ± 12 y, time post surgery: 80 ± 18 m). We compared the results to reference values obtained from eight healthy peers (age: 33 ± 10 y).

Results

The patients exhibited slight asymmetries in step length (smaller steps) and stance time (longer stance) as well as lower hip abduction moments in the operated limb in early stance compared to the non-operated limb. However, there were no differences in gait compared to healthy controls, even though the patients showed reduced bilateral hip abduction strength compared to controls.

Conclusions

Our results indicate that the patients’ gait pattern had generally recovered very well, despite slight asymmetries in spatiotemporal parameters. Subtle deviations in hip abduction moments were observed during gait, whereas hip abduction strength was substantially reduced. Hence, the patients walked at a higher percentage of their maximal capacity. They may, therefore, be prone to fatigue and adopt compensatory gait strategies more quickly than healthy peers when walking long distances.

A comparison of biomechanical changes on femoral head following rotational acetabular osteotomy and eccentric rotational acetabular osteotomy in normal cadaveric hip

PURPOSE

Both rotational acetabular osteotomy (RAO) and eccentric rotational acetabular osteotomy (ERAO) are effective procedures for young patients with developmental dysplasia of the hip. However, no comparative study of biomechanical changes has been reported following these two procedures. We therefore explored the stress changes on femoral head after RAO and ERAO under different load conditions.

MATERIALS AND METHODS

Twelve female cadaveric hips without deformity were divided into RAO group and ERAO group. Stress value on femoral head was measured preoperatively and postoperatively after the vertical force was loaded on the cadaveric spine from 0 to 500 N. Stress change value was then calculated base on the measurements.

RESULTS

In the RAO group, preoperative stress increased when loading on spine became larger, but postoperative stress changed its increasing trend into decreasing when the load was greater than 200 N (turning point). Same phenomenon was found in the ERAO group (turning point was 300 N). However, the difference between preoperative and postoperative stress was not statistically significant in both RAO and ERAO groups. Stress change value from each procedure showed similar trends. With the load growth, stress change increased firstly and then decreased, but the difference between RAO and ERAO was not statistically significant.

CONCLUSIONS

Both RAO and ERAO could correct the abnormal biomechanical effect of dysplastic hip; moreover, they may have similar biomechanical effects on femoral head, obtaining the same clinical outcomes. Non-biomechanical factors (surgical trauma, technical complexity, etc.) also play important roles in procedure selection.

Periacetabular osteotomy reduces the dynamic instability of dysplastic hips

We compared the dynamic instability of 25 dysplastic hips in 25 patients using triaxial accelerometry before and one year after periacetabular osteotomy. We also evaluated the hips clinically using the Harris hip score and assessed acetabular orientation by radiography before surgery and after one year. The mean overall magnitude of acceleration was significantly reduced from 2.30 m/s(2) (sd 0.57) before operation to 1.55 m/s(2) (sd 0.31) afterwards. The mean Harris hip score improved from 78.08 (47 to 96) to 95.36 points (88 to 100). The radiographic parameters all showed significant improvements. This study suggests that periacetabular osteotomy provides pain relief, improves acetabular cover and reduces the dynamic instability in patients with dysplastic hips.

Triple pelvic osteotomy as treatment for osteoarthritis secondary to developmental dysplasia of the hip

Joint-preserving osteotomies are an established treatment for adult hip pain secondary to developmental dysplasia of the hip. However, their value for advanced osteoarthritis is unclear. Therefore this study addresses the question of long-term results of triple pelvic osteotomy in patients with second grade osteoarthritis. Thirty-two patients with second grade osteoarthritis secondary to developmental dysplasia of the hip before triple pelvic osteotomy were clinically and radiographically assessed 11.5 years postoperatively. Five patients required conversion to total hip replacement. Kaplan-Meier survivorship analysis predicted a survival rate of 85.3%. The mean Harris hip score increased significantly with more than 56% good or very good results. A preoperative BMI > 25 and Harris hip score < 70 resulted in worse outcome or early conversion into total hip arthroplasty. The results indicate that developmental dysplasia of the hip even in second grade osteoarthritis can be treated with triple pelvic osteotomy.

Multiple drillings of the acetabular fossa induce early joint remodeling after rotational acetabular osteotomy for hip dysplasia

INTRODUCTION

We previously observed medial and/or lateral expansion of the subchondral bone in the acetabulum 3 years postoperatively in two out of three cases in which rotational acetabular osteotomy (RAO) was performed. Then we performed multiple drillings at the acetabular fossa in order to induce expansion of the medial subchondral bone in the acetabulum. The purpose of this study is to evaluate the effect of multiple drillings on early joint remodeling after RAO.

PATIENTS AND METHODS

Twenty-one women (21 joints) who had undergone RAO with multiple drillings at acetabular fossa (group D) were included. As a control group, 12 women (14 joints) without drillings in RAO procedure were observed (group C). The center-edge angle (CE angle), acetabular roof obliquity (AC angle), head lateralization index (HLI), and the angle between medial and lateral edge of acetabular roof (LOM angle) were measured on the radiographs preoperatively, at 1 month, 2 years postoperatively, and at the last follow-up.

RESULTS

As regards the mean CE angle, AC angle, and HLI, there was no significant difference between the two groups. The mean LOM angle at 2 years and the last follow-up demonstrated significant difference between the two groups.

INTERPRETATION

Biomechanical and anatomical changes after RAO cause increasing stress to the medial side of the acetabulum. Moreover, bone marrow-stimulating procedure at acetabular fossa might be beneficial to develop early joint remodeling affected by bone marrow derived cells such as mesenchymal stem cells.

Triple osteotomy of the pelvis for acetabular dysplasia: age at operation and the incidence of nonunions and other complications influence outcome

We investigated the variables which determine the outcome after triple osteotomy of the pelvis for the treatment of congenital dysplasia of the hip. We reviewed 51 patients (61 hips) with a median age at operation of 23 years who were treated with a Tönnis triple osteotomy. The median follow-up was six years with a minimum of two years. Eight patients (eight hips) required a revision procedure. Of the remaining 53 hips, the results were good or excellent in 36 (68%) when evaluated according to the Harris hip score (median 90 points), and 33 patients (65%) were satisfied with the procedure. Logistic regression analysis indicated that the incidence of complications such as nonunion at an osteotomy site influenced patient satisfaction (p = 0.079). The incidence of complications correlated positively with increasing patient age at operation (p = 0.004). The amount of acetabular correction did not correlate with patient satisfaction. In univariate analysis, the groups of 'satisfied' and 'not satisfied' patients differed significantly in Harris hip score, age, incidence of nonunion at the osteotomy sites, complications and late revisions. In conclusion, the patient's age at operation and the incidence of complications influence patient satisfaction after triple osteotomy, but the amount of radiologically evident acetabular correction shows no correlation to outcome.

Triple osteotomy of the innominate bone. 1973

In forty-five patients, twenty-three with congenital dislocations and the rest with paralytic or other disturbances, this new displacement osteotomy of the hip joint was done when other iliac osteotomies were considered ineffective. The patients, seven to seventeen years old, were followed two to ten years. Of the fifty-two procedures, forty were satisfactory. Most of the unsatisfactory results were in cases of myelodysplasia, peroneal atrophy, and cerebral palsy.

Rotational acetabular osteotomy in patients forty-six years of age or older: comparison with younger patients

BACKGROUND

Satisfactory intermediate and long-term results of periacetabular rotational osteotomy for early osteoarthritis secondary to dysplasia of the hip have been reported for patients in the third and fourth decades of life. The purpose of the present study was to examine the usefulness of rotational acetabular osteotomy in patients older than forty-six years of age.

METHODS

A retrospective review of two groups of patients who had been treated with a rotational acetabular osteotomy was conducted. The older group consisted of twenty-four patients (twenty-six hips) with early-stage osteoarthritis who had a mean age at the time of surgery of 50.9 years (range, forty-six to fifty-eight years) and a mean duration of follow-up of 8.2 years (range, five to thirteen years), and the younger group consisted of sixty patients (sixty-three hips) who had a mean age at the time of surgery of 34.4 years (range, thirteen to forty-five years) and a mean duration of follow-up of 8.3 years (range, five to fourteen years). Clinical follow-up was based on the system of Merle d'Aubigne and Postel. The center-edge angle, acetabular roof angle, and head lateralization index were measured on radiographs made preoperatively, postoperatively, and at the time of follow-up. Preoperative and postoperative joint congruencies were classified into four grades.

RESULTS

Preoperatively, the mean Merle d'Aubigne clinical score was 13.9 points in the older group and 14.1 points in the younger group. In both groups, this score improved significantly to a mean postoperative follow-up score of 16.6 points (p < 0.0001), with no significant difference between the two groups. The mean center-edge angle improved from 3.2 degrees preoperatively to 34 degrees postoperatively (p < 0.0001) in the older group and from -2.1 degrees preoperatively to 34 degrees postoperatively (p < 0.0001) in the younger group. The mean acetabular roof angle improved from 29 degrees to 5.9 degrees (p < 0.0001) in the older group and from 31 degrees to 2.9 degrees (p < 0.0001) in the younger group. The mean head lateralization index improved from 0.67 to 0.64 (p < 0.01) in the older group and from 0.66 to 0.61 (p < 0.0001) in the younger group. Progression of osteoarthritis was observed radiographically at the time of follow-up in five hips in the older group and in four hips in the younger group. Kaplan-Meier survivorship analysis, with radiographic progression of osteoarthritis as the end point, predicted a ten-year survival rate of 70.0% in the older group and 93.7% in the younger group; this difference was not significant, with the numbers available (p = 0.062, log-rank test).

CONCLUSIONS

Our results indicate that rotational acetabular osteotomy for elderly patients can prevent progression of osteoarthritis (as indicated by a survival rate of 70% at ten years) and that in selected cases it is worthwhile at least as a temporizing operation.

Endoscopic pelvic osteotomy for the treatment of hip dysplasia

Adolescent and adult hip dysplasia can be surgically treated by rotating the acetabulum into a better weight-supporting position; however, open pelvic osteotomies are among the most invasive of all pediatric orthopaedic procedures. Endoscopic pelvic osteotomy offers the theoretical advantages of magnified visualization of the bone cuts, minimized surgical dissection, and rapid postoperative recovery. The technique of endoscopically assisted triple innominate osteotomy requires the combination of endoscopic skills and facility with more standard surgical approaches.

Rotational acetabular osteotomy for hip dysplasia: spontaneous medial enlargement of the acetabulum

We followed 56 patients (63 joints) who had undergone rotational acetabular osteotomy (RAOs) between 1987 and 1993, mean 7 (5-12) years. The Merle d'Aubigné score increased by 15 points or more in 59 and decreased in 4 hips. The arthrosis progressed in 5 joints. In about 2/3 of the cases, we observed some medial and/or lateral expansion of the subchondral bone in the acetabulum 3 years postoperatively, suggesting enlargement of the load-bearing area.

Pre- and postoperative three-dimensional computed tomography analysis of triple innominate osteotomy for hip dysplasia. J Pediatr Orthop. 2000;20:116-123. [PMID: 10641700 DOI: 10.1097/01241398-200001000-00023]

Traditional methods of analysis and surgical techniques for hip dysplasia concentrate on frontal-plane analysis of the hip. More recent studies on imaging and operative correction of hip dysplasia recommend three-dimensional (3D) analysis, and some have mentioned but not emphasized the importance of transverse-plane acetabular anatomy (anteversion/retroversion). In this study we found that failure to analyze and understand transverse-plane acetabular anatomy can contribute to complications after triple innominate osteotomy (TIO). A subset of seven patients (eight hips) who were treated with TIO for deficient acetabular coverage resulting from hip dysplasia or Legg-Calvé-Perthes disease had both pre- and postoperative 3D computed tomography (CT) studies. Most of the postoperative studies were obtained to analyze complications (external limb rotation, nonunion). Analysis of the 3D CT studies showed a change in the position of the acetabular fragment after osteotomy into greater adduction, anterior rotation (extension), and external rotation, improving femoral head coverage. All of the hips had increased external rotation of the acetabulum after TIO. Excessive external rotation (>10 degrees) was noted in five hips, and these included two hips with pubic osteotomy nonunion, two with ischial nonunion, and one with marked external rotation of the lower limb. External rotation of the acetabular fragment during redirectional pelvic osteotomy can result in (a) excessive external rotation of the lower limb, (b) decreased posterior coverage, (c) increased gaps at the pubic and/or ischial osteotomy sites with resultant higher rates of nonunion, and (d) lateralization of the joint center. The surgical technique for TIO should be designed to avoid excessive external rotation of the acetabular fragment.

Acetabular coverage of the femoral head after triple pelvic osteotomy: no relation to outcome in 51 hips followed for 8-15 years

In developmental dysplasia of the hip in adolescents and young adults, pelvic osteotomies aim to improve acetabular coverage of the femoral head by reorienting the acetabulum. We determined whether acetabular coverage is related to long-term clinical results after triple osteotomy of the pelvis. We used a previously published computer program (Konishi and Mieno 1993) which calculates three-dimensional coverage of the femoral head from plain anteroposterior radiographs. We studied the pelvic radiographs of 51 hips in 43 patients and the results were correlated with studies on clinical outcome (de Kleuver et al. 1997). Total acetabular coverage improved from a mean of 56% to 70%. We did not find a relationship between total acetabular coverage and long-term outcome, nor could we determine an optimal coverage. Reduced coverage of the posterolateral quadrant of the femoral head was related to a reduced score for walking ability (p = 0.03), and therefore care should be taken not to overcorrect the acetabulum forwards when attempting to improve the deficient anterior coverage. We challenge the concept that total acetabular coverage is a prerequisite for a good long-term outcome after triple pelvic osteotomy, and hypothesize that other factors such as the change in load across the hip are probably more important in determining the outcome.

Three-dimensional displacement of the hip joint after triple pelvic osteotomy. A postmortem radiostereometric study

Triple pelvic osteotomy reorients the acetabulum relative to the pelvis in order to improve acetabular coverage of the femoral head in cases of acetabular dysplasia. We undertook a radiostereometric analysis (RSA) on 6 osteotomized cadaver hips to determine the actual three-dimensional reorientation obtained. The centers of the femoral head were all translated posteriorly between 11 and 41 mm, and distally up to 13 mm. 4 were lateralized up to 8 mm, and 2 were medialized up to 5 mm. All acetabuli rotated anteriorly about the lateral to medial axis (X-axis), and 4 rotated outwards around the distal to proximal axis (Y-axis). The correlations between measurements performed on conventional anteroposterior radiographs and the RSA measurements were poor: variations in the lateral-medial direction ranged from -16 to +6 mm, and in the distal-proximal direction between -10 and +12 mm. The changes in orientations measured will significantly affect the load across the hip joint, since the dimensions of the pelvis change and the moment arms of the muscles, their lengths and lines of action are changed as well. We conclude that, with the procedures presently performed, the loads across the hip joint are bound to change, and that the reorientation can hardly be checked with conventional radiographs.