Revision Hip Arthroplasty Case Title: Revision THA Acetabulum Paprosky Type IIIA. ARMD with Metallosis with Severe Periacetabular Osteolysis and Co-Cr Levels >7 μg/L

 Revision THA Acetabulum Paprosky Type IIIA. ARMD with Metallosis with Severe Periacetabular Osteolysis and Co-Cr Levels >7 μg/L

 

 

1. Demographics

    

   Age: 79 Sex: Male BMI: 28

    

2. Relevant Past Medical History

    

   Principal pathologies: Pain, inability to walk, limitation of ROM, non-weight bearing on the right side

   Previous surgical procedures: Bilateral THAs 10 (right) and 15 (left) years back using uncemented proximally coated and cylindrically tipped stems and XLP poly in metal shell back in the acetabulum

   Medication: Antihypertensives, NSAIDs

   History of presenting complaint: Pain, inability to walk, and dysfunction of the right hip

    

3. Clinical Examination

    

   Symptoms: Pain and functional Trendelenburg due to the inability to bear weight on the left

   Range of motion: Flexion: 70; extension: 0; internal/external rotation very painful and limited; abduction: 25; adduction painful and impossible

   Specific tests: Unable to perform on the right

   Main disability: Inability to walk Scoring if available: HHS: 60 Neurovascular evaluation: Intact

    

4. Preoperative Radiological

   Assessment/Imaging (Fig. 19.1)

    

    

    

   Fig. 19.1 Right THA acetabular component loose with severe osteolysis at the roof and the ischial tuberosity. Bobble-shaped roof osteolysis is typical of the polyethylene debris-related osteolysis. Also, the small wire fragment adjacent to the teardrop indicated that the marking wire of the polyethylene wass broken; thus, the head rubs against the metal liner. It is expected that some degree of metallosis and ARMD will be present

    

5. Preoperative Planning

    

   Diagnosis: Osteolysis and need for acetabular revision with some augmentation to support the socket (Fig. 19.1).

   Possible treatment options: This is an uncontained defect Paprosky type IIIA that requires solid reconstruction with augments and revision trabecular metal shell to press fit the periphery of the acetabulum.

   Chosen treatment method: Exclusion of an infection via biochemical testing and joint aspiration. The tap sample was negative for microorganisms. ESR was elevated; the CRP was normal with WCC normal. Cobalt and chromium serum levels

   were just below seven μg/L; the patient was having, however, symptoms; the diagnosis of ARMD with extensive hard and soft tissue local destruction was suspected. Tantalum augment 54 mm by 10 mm thickness and bone graft, jumbo shell tantalum size 68 mm, and a liner size 59 mm with cement with a 32 mm diameter head.

   Selection of implants if applicable and rational: Trabecular metal augments and shell for better bone integration. A solid allograft could also do for the reconstruction of the uncontained defect.

   Expected difficulties: Stable reconstruction of the acetabular defect. Coordination of the augment placement and the acetabular shell insertion.

   Strategies to overcome difficulties: Variability of augments to match the defect.

   Templating: Performed preoperatively.

    

6. Surgical Note

    

   With the patient in lateral decubitus position, a posterior approach of the hip was used. The joint was aspirated again but no fluid could be extracted easily. Entering the joint a creamy fluid dark colored came through confirming the diagnosis of metallosis and ARMD. Extensive removal of the affected tissues led to the exposure of the lateral pelvic aspect with the acetabulum easily viewed. Six tissue samples were sent for microbiology and biopsy to detect ALVAL. The stem was stable, and decision was made to leave it in situ. The femoral head was removed easily to allow access and better visualisation of the acetabulum. The femoral part of the joint was then moved anteriorly in front of the anterior acetabular wall, and the acetabulum was exposed. The implant was holding well from the screws; however, the bone all around it was severely compromised and eroded. The liner was removed using a liner elevator, and the shell was exposed. The screws were removed and the cup carefully extracted utilising the explant device (Zimmer). The defect

    

   was detected and was large enough to justify the use of a large augment to the roof. Reaming of the defected roof to shape it to the size of the appropriate augment and to remove the debris and the scar tissue until exposure of bleeding cancellous bone occurred. Then attention was turned to the acetabulum below. The teardrop and transverse ligament were identified, and concentric reaming started to bring the reamer up to 66 mm. Full tantalum revision socket goes up to 68 mm; thus, the reaming was stopped and the acetabular defect was reconstructed using dummy implants. A roof wedge tantalum augment 54 mm by 10 mm thickness and bone graft used to reconstruct the roof. The augment was inserted tightly and then stabilized with 2.6 mm screws through the augment screw holes. The dummy socket was again tested below the inserted augment and was measured 66 mm. To allow some distraction and better fitting, a jumbo shell tantalum size 68 mm was elected. One mix of Palacos cement was prepared and was applied in the interface between the augment and the shell. The 68 mm shell was then inserted tightly, and the cement was scrapped off the interface quickly. Then several long screws were passed through the shell to the augment to the bone of the roof for interdigitating stability. Using the diamond-tipped speed burr, extra screw holes were opened up against the roof and extra screws inserted including an iliac screw below. The appropriate HXLP size 59 mm (Zimmer) was cemented in place with a 32 mm inner diameter for the appropriate ceramic head to be used. Fresh frozen allograft filled the ischial defect and the upper part of the femoral metaphysis that was mildly osteolyzed. Stability and leg length were found satisfactory (Fig. 19.2).

    

7. Intraoperative Challenges

    

   Challenges and solutions: Coordination of the roof augment and the shell insertion with the cement interface and screw insertion and stabilization.

   Unanticipated problems and solution: Increasing the acetabular reaming to a jumbo

   size must be resisted when the fit to the anterior and posterior is good. The roof must be addressed separately and reconstructed. Increasing the reaming size may risk fracture of the walls that will compromise the acetabular integrity severely.

   Thorough description of decision-making, including the reason for the final decision: Uncemented reconstruction was elected for the acetabular part as there is good evidence that trabecular metal shell can fit tightly into compromised acetabular defects and allow bone ingrowth. For the roof part of the reconstruction, a solid fresh frozen allograft could do the job as the defect is uncontained and the solidity is important for early stability. Trabecular augments can do the same, as it can be filled with morselized fresh frozen allograft or occasionally can be combined with a solid part of allograft if the defect is not concentric.

    

8. Postoperative Radiographs

   (Fig. 19.2)

    

    

    

   Fig. 19.2 Acetabular reconstruction using tantalum augment and shell. Screws through the shell and the augment up to the iliac wing. Jumbo-sized shell with good fit to the periphery of the acetabulum down to the teardrop maintaining the leg length equality to the contralateral side

    

9. Postoperative Management

    

   Chemoprophylaxis and anticoagulant treatment period: Cefuroxime 750 mg (one dose preoperatively and two doses postoperatively), vancomycin 500 mg (one dose preoperatively and two doses postoperatively), and LMWH during hospitalization then rivaroxaban 10 mg for 30 days.

   Gait/limb loading until full loading: Partial weight bearing for eight weeks and then as tolerated.