BILATERAL SIMULTANEOUS TWO-INCISION MINIMALLY INVASIVE TOTAL HIP ARTHROPLASTY

Abstract

The two-incision technique uses strategically located incisions to insert the prosthesis components in to specific intermuscular or internervous planes in an effort to minimize damage to these tissues. Even though there are many reports about safety and benefits of bilateral simultaneous total hip arthroplasty (THA), none of them has reported about either one-incision or two-incision bilateral simultaneous minimally invasive (MI) THA. This study aimed to assess the feasibility of bilateral simultaneous MI two-incision THA in terms of clinical, radiological and functional outcomes.

Sixty two patients, in the age of 24 to 69 years were operated for bilateral simultaneous THA using modified two-incision technique and followed for average 41 months. In the technique of two-incision THA described by Mears, they used modification of Smith Peterson approach for insertion of acetabular component and femoral component is inserted through a small incision situated between greater trochanter and iliac crest, centered directly in line with the femoral shaft. We modified this technique and used part of Watson Jones approach for insertion of acetabular component with patient in lateral position. The posterior incision for insertion of femoral component is through intermuscular interval between gluteus medius and piriformis.

The average Harris Hip score improved from 41.8 (range 10 to 59) preoperatively to 95.3 (range 73 to 100) postoperatively (P < 0.05). WOMAC score improved from median of 66.2 (range 31 to 96) preoperatively to 5.0 (range 0 to 19) postoperatively (P < 0.05). Forty-nine (79.03%) patients were pain-free at the time of first follow up (6 weeks after surgery) and remained pain-free till the last follow up, while remaining 13 (20.97%) had only slight pain. Out of those 13, 3 patients complained of occasional mild pain at last follow up. Fifty (80.64%) patients were walking without limp, while remaining 12 (19.35%) had only slight limp at 6 months. Out of those 12, 2 patients had persistent limp at final follow up. Fifty-eight (93.53%) patients were walking without support, 56 (90.32%) were able to walk unlimited distance and 55 (88.70%) were able to climb stairs without using a railing. Walking with walker was started on average 3.7 days (range 1 to14 days) and walking with crutches was started on average 10.3 days (range 1 to 49 days) postoperatively. Patients were able to walk without support on an average 48 days (range 14 to 120 days) and use stairs without support and without any discomfort on an average of 50 days (range 5 to 150 days). The average lateral opening angle of acetabulum was 40 ° and anteversion was 12 °. All femoral components were implanted in neutral to 5 ° valgus position. None of the femoral component showed subsidence of more than 3 mm. The filling of the femoral canal by the prosthesis was excellent in all cases. Post-operative periprosthetic fracture occurred in 2 patients and delayed infection occurred in 1 patient.

In conclusion, bilateral simultaneous two-incision minimally invasive THA gives satisfactory clinical and radiological results in comparison with conventional THA. It is safe in experienced hands, without any additional risk of complications. It provides excellent functional outcome and patient satisfaction.