Revision Hip Arthroplasty Case Title: Acetabular Revision ‘Cup-Cage Techniques’

Demographics

 

Age: 73 Sex: Female BMI: 23

 

Relevant Past Medical History

 

Previous surgical procedures: Left hip—shelf arthroplasty 1962, THA 1985. Right hip THA 1989

Medication: Painkiller

Other: Rehabilitation

History of Presenting Complaint: Progressive groin pain over the last five years. Limping

 

Clinical Examination

 

Symptoms: Left groin pain for two years. Walk with two crutches for one year.

Range of motion: The range of motion was severely decreased (flexion 45, abduction 0).

Main disability: Leg length discrepancy close to 20 mm. Abductor muscle strength were quite sound (4/5). Two previous approaches: one Smith Petersen and one posterior approach.

Scoring: Harris Hip Score, 42.

Neurovascular evaluation: Normal.

Preoperative Radiological Assessment/Imaging (Figs. 20.6 and 20.7)

 

 

 

Fig. 20.6 Preoperative AP view of the pelvis

 

 

 

 

Fig. 20.7 CT scan with arteriography

 

Preoperative Planning

 

Diagnosis: Isolated aseptic cup loosening with acetabular protrusion (Paprosky IIIB) (Figs. 20.6 and 20.7).

Possible treatment options: Impaction grafting with a cage, massive allograft with a cage, a dedicated cage is an antiprotrusio cage (i.e. Burch-Schneider), cup-cage construct with porous tantalum components.

Chosen treatment method: Cup-cage construct with porous tantalum components.

Selection of implants if applicable and rational: Porous hemispheric tantalum-made cup with screws protected by a Burch-Schneider ring. Cementation of a UHMWPE Liner.

Expected difficulties: The joint access, the cup removal, a possible vascular injury and lengthening. Strategies to overcome difficulties: Extended trochanteric osteotomy may be used if the access

to the joint is impossible.

 

Surgical Note

 

Patient’s position: Lateral.

Type of anaesthesia: General.

Surgical approach: You may use any approach for hip revision. The posterior approach, however, is the best one to assess the posterior column that is mandatory to achieve the reconstruction in this case.

Main steps: Posterior approach to the joint and luxation. Femoral head and cup removal. The foramen obturator has to be found to locate the appropriate hip centre. Reaming of the cup to reach two points of contact with the ischium and the ilium. Find the proper size of the cup using a trial. The trial needs to be stable by pushing gently with a tool or fingers. If not, then use a bigger one. The dedicated final component is then impacted and if possible fixed with screws.

Prepare of the ischium with an osteotome to receive the Burch-Schneider ring with the appropriate inclination and anteversion. Use of multiples screws in the acetabular roof. Then cement of a liner in 15–20° of anteversion and 40° of inclination with the maximum possible inner diameter to avoid instability. Reduction of the femoral component with a femoral head trial (Fig. 20.8).

Reconstruction techniques: Cup-cage construct.

 

Intraoperative Challenges

 

Challenges and solutions: Obtain a stable fixation of the tantalum-made cup whilst remaining possible the insertion of the ring in the right position.

Unanticipated problems and solution: Instability of the hip or inability to achieve a hip reduction. It can be managed by restoring the hip centre as close to normal as possible. A femoral release can also be performed to lengthen the limb. If the reduction remains impossible, then consider femoral stem revision.

 

Postoperative Radiographs

(Fig. 20.8)

 

 

 

Fig. 20.8 Pelvis AP view

 

Postoperative Management

 

Chemoprophylaxis and anticoagulant treatment period: Low molecular weight heparin for a month

Gait/limb loading until full loading: Partial weight bearing with two crutches for six weeks

 

Follow-Up and Complications

 

Scoring: Harris Hip Score: 84.

 

Discussion

 

Advantages of the applied method: Bone ingrowth. No graft resorption. Postoperative weight bearing allowed.

Disadvantages of the method: More expensive. Short to midterm follow-up available only.

Alternative evidence-based techniques for the case: Impaction grafting, bulk allograft protected by an antiprotrusio ring, cementless high hip cup and cementless jumbo cup.

Why is the chosen technique better for this case? No graft resorption. Postoperative weight bearing allowed.

Indications and contraindications for your technique: No contraindication. The best indication is the implant loosening with protrusion (Paprosky IIIB or IIC) associated with a pelvic discontinuity.

Learning curve and how to manage complications: Its’ a modular system. Primary stability is mandatory as for any other cementless fixation. Gain this by using porous metal augmentation and screws.

Level of evidence concerning the superiority of this method against others: Few retrospective studies on limited number of patients (level 4). Some non-comparative prospective monocentric or multicentre studies. Two recent meta-analyses [1, 5, 14].