Ottopelvis

Ottopelvis

1. OTTO PELVIS Dr. Pratik Dhabalia Resident in Orthopedics Dr DY Patil Hospital, Navi Mumbai

2. The German pathologist Otto first described Protrusio acetabuli in 1824. also known as ‘ arthrokatadysis ’ Hence also known as Otto Pelvis

3. Protusio Acetabuli Two types: Primary Protusio AKA Otto pelvis AKA arthrokatadysis Secondary Protusio

4. ETIOLOGY PRIMARY PROTUSIO ACETABULI Remains a diagnosis of exclusion As such many of the cases reported in the past may have in fact been secondary to undiagnosed conditions. Following three headings: An inflammatory or destructive condition of the hip joints; A qualitative deficiency of acetabular bone; A developmental abnormality or growth disturbance.

5. Secondary protusio acetabuli

6. Clinical Features Marked female predilection More common in middle aged persons The condition is characteristically bilateral Typically, patients with primary protrusio acetabuli present with increasing stiffness rather than pain Deepening of the acetabulum leads to painful limitation of abduction as the femoral neck impinges on the superior acetabular margin Further progression leads to adductor spasm, and fixed flexion deformities develop Untreated, the patient ultimately develops ankylosis of the affected hip.

7. RADIOGRAPHS Kohler’s Line Protrusio acetabuli is identified on anteroposterior (AP) radiographs of the pelvis with an acetabular line projecting medial to the ilioischial line 3 mm in males or 6 mm in females.

8. If central edge angle is greater than 40 degrees protrusio is present. Radiographic differences between protrusion hips and the OA group: In the protrusio group, the medial joint space was decreased and the superior joint space was increased when compared to the OA group. All hips in the protrusio group had an ilioischial line lateral to the acetabular fossa, whereas the opposite was observed in the hips of the OA group. The posterior rim was lateral to the center of rotation in greater percentage of the hips in the protrusion group than in the OA group. Parameters that measure lateral coverage, center edge, and Sharp’s angle were greater in the protrusion group compared to the OA group. The center of rotation of the femoral head was lower than the tip of the greater trochanter in 93% of cases in the protrusion. The OA group, in contrast, had a center of rotation of the femoral head lower than the tip of the trochanter in 69% of the hips. The neck-shaft angle of the protrusio group was substantially Less than OA group.

9. ACETABULAR TEAR DROP

10. MANAGEMENT The management of protusio acetabuli depends on age and degree of degenerative change. In the young, skeletally immature patient with progressive secondary protrusio aceTabuli , early surgical fusion of the triradiate cartilage with or without valgus intertrochanteric oste - otomy is appropriate. As it is not possible to anticipate which patients with primary protrusio acetabuli in the younger age group will progress to a severe deformity, fusion of the triradiate cartilage cannot be recommended for primary protrusio acetabuli . Valgus intertrochanteric osteotomy is recommended in skeletally mature patients with no degenerative change under 40 years of age. Over 40 years, this procedure can still be carried out in patients with no degenerative changes in their hip joint and who are capable of undertaking the associated rehabilitation. In older patients, total hip arthroplasty with medial bone grafting and meticulous attention to returning the hip joint to its anatomical center is the procedure of choice.

11. Joint Preserving Surgery • For young adult without arthritic changes. • Valgus intertrochanteric proximal femoral osteotomy. • Rarely arthrodesis for young with heavy manual work. Joint Replacement in Protrusio Joint replacement surgery may be necessary in the case of severe pain or substantial joint restriction A lot of intraoperative problems may be encountered in protrusion hips. Hence, it is called as “Problem in depth”. Protrusio is matter of concerns. The concerns are both mechanical and biological.

12. Mechanical Concerns Bone can be inherently structurally impaired to provide stable prosthesis fixation Preoperative limitation of movement range can be problematic for exposure and dislocation of hip Higher risk of impingement leading to subluxation or dislocation, or wear Limb length discrepancy is a problem Abducter insufficiency.

13. Biological Concerns Failure to achieve ingrowth into porous implant In case of cemented acetabulum there may be lack of stable interface with cement. Correction of protrusio is important and objectives of total hip arthroplasty in a protrusio are as follow: Strengthen medial wall and restore acetabular integrity Lateralize acetabular component to restore hip biomechanics and center of hip rotation Ensure acetabular component coverage Secure rigid prosthesis fixation Reconstruct the defect.

14. TREATMENT OPTIONS Restoration of the hip center can be accomplished by a variety of surgical techniques. • Cement augmentation • Bone grafts: Auto or allografts With bipolar prosthesis With cementless • Support rings Burch-Schneider’s ring Müller’s ring. Surgical technique of total hip arthroplasty is demanding in case of protrusio . Careful preoperative planning and evaluation is vital for successful outcome. The aim in protrusio surgery is to achieve two important objectives: 1. Restitution of bone stock 2. Lateralization of the hip center to the anatomic position to maximize the chances of successful long-term outcome.