Kei Shiramizu

Curved periacetabular osteotomy for treatment of dysplastic hip.

The Bernese periacetabular osteotomy has a considerable rate of postoperative complications such as reflex sympathetic dystrophy, motor nerve palsy, heterotopic ossification, and delayed union of the ilium, which are assumed to be caused by extensive exposure or asphericity of the osteotomy surfaces. To address these issues, we developed the curved periacetabular osteotomy, a modification of the Bernese periacetabular osteotomy which limits dissection, prevents the outside of the ilium from being exposed, and produces osteotomy surfaces with the same curvature. Curved periacetabular osteotomies were done on 128 hips in 118 patients whose average age at the time of surgery was 35.2 years (range, 16–59 years). The average followup was 46 months (range, 24–99 months). The average center-edge angles were 4° (range, −15°–5°) preoperatively and 35° (20°–55°) postoperatively, and union of the iliac osteotomy was achieved in all hips. We experienced three asymptomatic pubic nonunions. Dysesthesias occurred in 27 patients along the lateral femoral cutaneous nerve and symptoms resolved in 23 patients within 1 year. The average Harris hip score improved from 72 to 93 points. There were no major complications such as sciatic nerve palsy, abductor dysfunction, or heterotopic ossification. Level of Evidence: Therapeutic study, Level IV (case series—no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Prevalence of femoroacetabular impingement in Asian patients with osteoarthritis of the hip

Although femoroacetabular impingement (FAI) has recently been considered to be one of the causes of osteoarthritis (OA) of the hip, the exact pathogeneses and incidence of FAI and primary OA are unknown. The purposes of this study were to investigate the causes of hip OA in Japan and to clarify the prevalence of FAI in patients with hip OA. We retrospectively investigated 817 consecutive patients (946 hips) who underwent primary surgery with the diagnosis of OA of the hip. Clinical recordings and preoperative radiographs were evaluated to determine the cause of OA. There were 17 hips who had primary OA, of which six hips were determined to be FAI positive. The remaining 11 cases without FAI had primary OA of unknown aetiology. Our study has revealed that most hip OA cases were caused by developmental dysplasia of the hip. We only found a few cases (0.6%) with FAI in Japan.RésuméBien que le conflit fémoro acétabulaire (FAI) ait été récemment considéré comme l’une des causes de l’arthrose (OA) de la hanche, la pathogénie exacte et l’incidence du conflit dans l’arthrose primaire restent malgré tout peu connues. Le but de cette étude est d’étudier les causes de l’arthrose de hanche au Japon et de clarifier la prévalence du conflit fémoro acétabulaire chez les patients présentant une telle arthrose. Nous avons respectivement revu 817 patients consécutifs (946 hanches) qui avaient bénéficié d’une intervention primaire chirurgicale pour le diagnostic d’OA de la hanche. Les données cliniques et les radiographies per-opératoires ont également été étudiées pour déterminer les causes de cette arthrose. 17 hanches présentaient une arthrose primaire, 6 sur les 17 étaient secondaires à un conflit fémoro acétabulaire. Pour les 11 hanches restantes, sans conflit fémoro acétabulaire, nous n’avons pu déterminer l’étiologie de l’arthrose. Notre étude révèle que la plupart des arthroses de hanche sont causées par la dysplasie de la hanche. Nous avons trouvé qu’un nombre de cas peu important, 0,6% de conflit fémoro acétabulaire au Japon.

L-shaped caliper for limb length measurement during total hip arthroplasty

The existing methods of assessing limb lengthening during total hip arthroplasty (THA) are prone to error because the measurements are not parallel to the limb lengthening axis. In order to address this, we designed a caliper to estimate limb lengthening during THA and evaluated its accuracy compared with our previous device, the straight caliper. Limb lengths were measured in 100 patients. The L-shaped caliper was used in 50 cases and the straight caliper in 50. The correlation between intra-operative and post-operative radiographic measurements was significantly improved using the L-shaped device (p < 0.0001, r = 0.934). This method was extremely accurate in predicting changes in limb length due to surgery.

Postoperative acetabular retroversion causes posterior osteoarthritis of the hip.

We retrospectively reviewed 68 hips in 62 patients with acetabular dysplasia who underwent curved periacetabular osteotomy. Among the 68 hips, 33 had acetabular retroversion (retroversion group) and 35 had anteversion (control group) preoperatively. All hips were evaluated according to the Harris hip score. Radiographic evaluations of acetabular retroversion and posterior wall deficiency were based on the cross-over sign and posterior wall sign, respectively. The clinical scores of the two groups at the final follow-up were similar. In the retroversion group, 12 hips had anteverted acetabulum postoperatively. The posterior wall sign disappeared in these hips, but remained in 21 hips with retroverted acetabulum postoperatively. Among the 21 hips with retroverted acetabulum, posterior osteoarthritis of the hip developed postoperatively in five hips. When performing corrective osteotomy for a dysplastic hip with acetabular retroversion, it is important to correct the acetabular retroversion to prevent posterior osteoarthritis of the hip due to posterior wall deficiency.RésuméNous avons revu de façon rétrospective 68 hanches chez 62 patients présentant une dysplasie acétabulaire et ayant bénéficié d’une ostéotomie péri-acétabulaire. Parmi ces 68 hanches, 33 avaient en préopératoire une rétroversion acétabulaire (groupe rétroversion) et 35 une antéversion (groupe contrôle). Toutes les hanches ont été évaluées selon le score de Harris. L’évaluation radiographique de la rétroversion acétabulaire et du mur postérieur déficient ont été basées sur le signe du croisement et le signe du mur extérieur. Les scores cliniques des deux groupes au suivi final était semblable. Dans le groupe rétroversion, 12 hanches avaient antéversé leur acétabulum en post-opératoire le signe du mur postérieur disparaissant, mais celui-ci restant présent dans 21 hanches avec un acétabulum en rétroversion post-opératoire. Parmi les 21 hanches avec acétabulum rétroversé une coxarthrose postérieure s’est développée à 5 ans post-opératoire. Lorsque l’on réalise une correction par ostéotomie pour une hanche dysplasique avec un acétabulum rétroversé, il est important de corriger cette rétroversion de façon à prévenir une coxarthrose secondaire due à la déficience du mur postérieur.

Modified pubic osteotomy for medialization of the femoral head in periacetabular osteotomy: A retrospective study of 144 hips

Background and purpose Medial displacement of the femoral head reduces the force transmitted across the hip joint. Since 2005, we have performed a modified Ganzs osteotomy with curved periacetabular osteotomy (CPO) to obtain medialization of the femoral head. The modification involves cutting of the pubis at 30 degrees to the horizontal line. Here, we examined whether this modified CPO procedure medialized the femoral head more than the conventional CPO procedure. Patients and methods 69 patients (mean age 37 years, 72 hips) treated with the modified CPO procedure (the M group) were compared with 68 patients (mean age 38 years, 72 hips) previously treated with conventional CPO (the C group). All patients were operated because of dysplastic hips. We used radiographic measurements from anteroposterior radiographs. The magnitude of the resultant hip force normalized with respect to the body weight (R/WB) and hip contact joint stress (Pmax/ WB) was calculated in all cases. Results The average lateral center‐edge (CE) angle, acetabular roof obliquity (ARO), and acetabulum‐head index (AHI) improved in both groups. The CE angle, ARO, and AHI were similar in the 2 groups before and after surgery. Medialization of the femoral head was larger in the M group than in the C group (p < 0.001). The average value of the resultant hip force decreased from 3.2 to 2.9 in the M group and remained unchanged, at 3.1, in the C group. In addition, the average value of the peak contact stress decreased more in the M group (from 9.4 kPa/N to 3.4 kPa/N) than in the C group (from 9.1 kPa/N to 4.3 kPa/N). Interpretation In dysplastic hips, the modified CPO reduces the contact hip stress more than the conventional CPO because of better medialization of the femoral head.

Quantitative anatomic characterisation of the pelvic brim to facilitate internal fixation through an anterior approach

Purpose. To define the centre of the hip joint and the bone stock around the hip joint from the supra-acetabular portion or pelvic brim so as to avoid penetration of guidewire into the hip joint when performing internal fixation using the anterior approach. Methods. A total of 42 cadavers were utilised. Measurements were completed before and after cutting the pelvis into 4 pieces. Before cutting the pelvis, the centre of the hip joint was measured on the pelvic brim. After cutting the pelvis, the bone stock around the hip joint was measured in each section. The pelvic brim and the anteroinferior iliac spine were utilised as guide points in the measurements, because these parameters could be determined during an anterior surgical procedure. Results. On the pelvic brim, the reflected centre of the hip joint centre was located approximately 3.2 mm anterior to the distal edge of the anteroinferior iliac spine. The mean minimum bone stock of the pelvic brim was 14.0 mm in the centre of the hip joint section. Conclusion. This study described the anatomical reference points around the hip joint, and the ways in which they can be utilised to increase the safety of the anterior approach for internal fixation. It is important to define the centre of the hip joint from the supra-acetabular portion or pelvic brim, given that it is not visualised during surgery using an anterior approach.

A quantitative anatomic characterization of the quadrilateral surface for periacetabular osteotomy

The periacetabular osteotomy described by Ganz et al is used widely, and includes an outward osteotomy from the quadrilateral surface. Because intraarticular extension of the osteotomy can complicate the Ganz osteotomy, it is important to image the margin of the hip. To prevent this complication, and to do this procedure more safely, 32 hemipelves from cadavers were used in the current study. Some landmarks were selected that can be clarified on the quadrilateral surface during the periacetabular osteotomy. The acetabulum was hollowed out using an acetabular reamer of the same size as each femoral head, and the margin of the penetrated hole through the acetabulum was determined using these landmarks. The posterior margin of the hip is located approximately 2 cm anterior to the sciatic notch. The anatomic guidepoint for the osteotomy of the ischium averaged 14 mm inferior to the distal margin of the hip. By clarifying the margin of the hip presumed on the quadrilateral surface in this way, the periacetabular osteotomy can be done more safely, without causing complications such as intraarticular chisel penetration.

Intraoperative Muscle Damage in Total Hip Arthroplasty

Tenderness in the medial and posterior thigh is sometimes observed during the early postoperative period after total hip arthroplasty (THA). In this study, the possible correlations of preoperative hip range of motion, surgical approach, and limb lengthening with postoperative muscle strain injury in THA were investigated. Sixty primary THA patients given the posterolateral approach or direct-lateral approach were examined. For comparison of the muscle strain injury in the 2 groups, we used magnetic resonance imaging. There were significant differences in postoperative thigh pain between cases in the posterolateral group with reduction of internal rotation and those with no reduction, and between cases in the direct-lateral group with reduction of external rotation and those with no reduction.

Cementless Total Hip Arthroplasty Using an Autograft of the Femoral Head for Marked Acetabular Dysplasia: Case Series

Purpose. To assess the short-term outcome of cementless total hip arthroplasty involving an autograft of the femoral head in Japanese patients. Methods. Cementless total hip arthroplasty with autogenous bone block grafting was performed on 18 hips in 15 patients with marked acetabular dysplasia. The resected femoral head was used as a graft for the superior-lateral region of the true acetabulum. Clinical outcome was correlated with the placement of the acetabular component, as revealed in radiographs. Results. The 13 women and 2 men had a mean age of 60.2 years (range, 37.0–73.0 years) at primary surgery and a mean follow-up duration of 3.3 years (range, 2.0–5.3 years). According to the classification of Crowe, 4 hips were in group I, 3 were in group II, one in group III, and 10 in group IV. The mean Harris Hip Score preoperatively was 45.7 (range, 19–69) and that at follow-up was 82.5 (range, 44–100). All 15 cases showed a good clinical outcome. There were no major intra-operative complications in this series. The grafted bones united in all patients. Two patients need surgical revision because the lateral insertion of the acetabular component resulted in loosening of it. Conclusion. Medial insertion of the acetabular component provides satisfactory short-term outcomes. Lateral insertion of the acetabular component during total hip arthroplasty should be avoided in patients with marked acetabular dysplasia.

Curved periacetabular osteotomy for the dysplastic hip: cadaveric and radiological analyses of safe procedures

Curved periacetabular osteotomy is a modified Ganzs procedure and requires an intrapelvic osteotomy. In order to establish the osteotomy line and the chisel inserting angles during the procedure, 32 cadavers and 28 three-dimensional computed tomographs were utilized. The guidepoints for the osteotomy line were obtained from the cadaveric analysis and the inserting angles of the chisel were measured from the radiological analysis. On the supra-acetabular portion, the C-shaped osteotomy line, starting from the proximal end of the anteroinferior iliac spine, should pass above the intersection point of the arcuate line and the line passing from the proximal end of the anteroinferior iliac spine to that of the ischial spine, and the chisel inserting angle should be 17° to the anterior surface of the ilium. On the quadrilateral surface, the C-shaped line should locate one finger width anterior to the greater sciatic notch, and the chisel inserting angle should be 25° to the quadrilateral surface. On the anterior aspect of the ischium, the chisel should advance with an inserting angle of 60° to the ground at the level of one finger width below the distal joint edge.