Introduction

Total hip arthroplasty (THA) is the most widely accepted surgical management for the treatment of avascular necrosis of femoral head, with favourable clinical outcomes reported in numerous studies [1–5]. THA is also considered as most effective and definitive treatment for osteoarthritis and other hip pathologies, such as rheumatoid arthritis, ankylosing spondylitis and osteonecrosis [6,7].

Approximately 20% of all patients who underwent THA will need surgery of the contralateral hip, at some time [8]. Studies suggest that since THA is most commonly done for primary osteoarthritis, which is usually a bilaterally involving hip pathology, and so patients, with unilateral THA could need a contralateral THA within 10 years [9,10]. Literature lacks in mid-term outcomes of bilateral THA in the Indian population.

Many surgical approaches to the hip are described, each with its distinctive advantages and disadvantages [11]. While some studies have found statistical associations between approach and outcome, most consider the individual surgeon’s comfort and proficiency with an approach as most important [12].

The posterolateral (Moore’s) approach which is most commonly used approach, permits quick access to hip joint with lesser tissue dissection and blood loss, but raising the risk of neurovascular injury and postoperative dislocation of the prosthesis [13-18]. In view of lack of literature on outcomes of bilateral THA, we evaluated the outcome of bilateral THA operated by posterolateral approach.

Material and Method

This longitudinal study was conducted from January 2018 to Jan 2020 in Orthopaedic department of our tertiary care centre in 25 patients with 50 arthritic hips who were operated by a single surgeon (1st Author) with bilateral THA via posterolateral approach (Southern Moore). Institutional ethical committee clearance and informed written consent was obtained before the study.

All patients of age more than 18 years with bilateral osteoarthritis or avascular necrosis of hip with grade III or IV were included in the study. Patients age less than 18 years, unilateral hip pathology, unfit for surgery or ankylosed hip were excluded from the study. In all the cases bilateral THA was performed, which was done as staged surgery and the second hip was replaced within 2 months of first THA.

All the patients were subjected to thorough history, clinical examination and investigations which include routine pre-operative profile, ESR and CRP. Standard pelvic roentgenogram true AP view with both hips including the upper third of femur, 15 degrees of internal rotation AP view and lateral X-rays of the hip were taken to estimate the anatomic relationship of the femur and pelvis, so that accurate restoration of combined anatomy and biomechanics of hip can be achieved. Aspirin, anticoagulants and other anti-inflammatory drugs, if patient was on, were stopped 7 days before the surgery.

Static quadriceps exercises were started and patient was mobilized in bed from day one. Weight bearing and walking with support was started from 2nd day postoperatively. Suture removal was done at 2 weeks. The contralateral hip was operated within 2 months of the primary THA. Patients were assessed functionally by Modified Harris hip scoring and radiologically by x rays for component placement and complications if any.

Results

25 patients (50 hips) with mean age 34.92 years (range 19 to 59 years), who underwent bilateral total hip arthroplasty were included in the study. Out of these patients 20 (80%) were male and 5 (20%) were females. Most common cause of AVN was idiopathic as seen in 13 (52.0%) patients, followed by steroid induced as seen in 6 (24.0%) patients, in 4 (16.0%) patients it was alcohol induced and one each had AVN due to post traumatic fracture neck of femur and sickle cell disease. Three patients had associated co-morbidities in form of diabetes mellitus alone in one patient, hypertension alone in one and both diabetes and hypertension in one patient. In rest of the patients no co-morbidities were present. Mean blood loss was 350 ml in surgery.

The mean pre-operative HHS was 28.28 ± 2.97 and 26.40 ± 2.31 for right and left hip which improved significantly to 89.96 ± 3.32 and 88.08 ± 12.53 respectively after 6 months of bilateral THA suggesting excellent outcome.

Peri-prosthetic fracture and radiculopathy occurred in one patient each, leg length discrepancy (LLD) was seen in 2 cases whereas in 3 cases unilateral dislocation was seen, all of which were treated accordingly. Hip dislocations were reduced on the same day under general anaesthesia. Maximum LLD was 2 cm which was treated by appropriate shoe raise.

Figure 2: Antero-posterior X ray of pelvis preoperative (a), after right THA (b), after left THA (c) and 6 months followup showing good position of components.

2(8%) of our patients had posterior hip dislocations postoperatively within one month, but were managed on same day with closed reduction performed under general anaesthesia. The functional outcome didn’t alter after the dislocation and was as good as other patients even at 6 months follow up.

Other complications in our series were periprosthetic fracture and radiculopathy occurred in one patient each, leg length discrepancy (LLD) was seen in 2 cases, the incidence of which is acceptable and comparable to other studies.

In our study, we tried to reduce the influence of confounding variables by selecting a homogeneous and undiversified cohort of patients who received the similar type of uncemented total hip prosthesis and all were operated on by a single surgeon. The study is limited by shorter follow up and small number of patients.

Conclusion

Bilateral THA can be employed in patients with mid-term excellent to good functional outcome, high satisfaction rate and lower rate of complications. Patients returned to their work after surgery, who previously were unable to do so and started doing most of the activities of daily living without any difficulties. Longer follow-up and multicentric studies with larger sample size are necessary to establish confirmatory results.

References