Introduction

Avascular necrosis (AVN) of the femoral head is one of the common causes of painful hip in a young adult. The natural course of this disease is one of relentless progression with eventual collapse of the femoral head, followed by secondary osteoarthritic changes in the hip.¹

The disease occurrence is more in men than in women. Most studies have attributed the disease process to the combined effects of genetic predisposition, metabolic factors, corticosteroid and excessive alcohol intake and local factors affecting blood supply such as vascular damage, increased intraosseous pressure, and mechanical stress.^2,3 This results in bone ischemia and infarction leading to bone death. Lastly, direct cellular insult may result from irradiation, chemotherapy, or oxidative stress may lead to AVN.

Total hip arthroplasty is the only effective treatment of AVN of the femoral head when the disease process has reached Ficat and Arlet stage 3 and 4. The primary indication for Total Hip Replacement in AVN is severe pain and the limitation in activities of daily living that it causes. To warrant doing total hip replacement, pain must be refractory to conservative measures such as oral nonsteroidal anti-inflammatory medication, weight reduction, activity restriction, and the use of supports such as a cane. Uncemented implants are most frequently used in young patients with high physical demands, where a revision surgical procedure in the future will be more likely.

Material and methods

The study was carried out on 50 hips of AVN Hip patients operated by uncemented total hip replacement in the Department of Orthopaedics, R.D. Gardi Medical College, Ujjain from August 2020 to August 2023. Information on the patients was compiled from clinical details, case files and operation theatre records. This is a prospective study. Patient follow up was for a minimum of 6 months to a maximum of 30 months (2 and a half years). Inclusion criteria was all the patients of Stage 3 and 4 of avascular necrosis of femoral head, patients in the age group more than 20 years and less than 70 years, patients willing to give informed consent and exclusion criteria was patients who had deformities or pathologies of other joints of the lower limb, which may have had an adverse bearing on the functional outcome of the surgery, the patients with systemic and local infections, patients who are not medically fit for surgery and patients not willing to give consent. Clinical presentation of osteonecrosis typically is asymptomatic in early stages, although patients may develop groin pain that can radiate to the knee or ipsilateral buttock. On physical examination, patients usually present with a limited range of motion at the hip and complain of pain particularly with forced internal and external rotation. A Thorough pre operative assessment like history, clinical and radiological examination and routine investigations of the patient done. Pre operative modified harris hip score was also evaluated. Current diagnosis is dependent upon plain AP and lateral radiographs of the hip, followed by MRI.

The AP radiographs will usually demonstrate the primary area of involvement, once changes can be viewed. Generally, the first radiographic changes seen by radiograph will be cystic and sclerotic changes in the femoral head. Early delamination of the cartilage from the underlying bone will most likely be demonstrated by the crescent sign[5].

All Total Hip Arthroplasty were performed under spinal anaesthesia. In all cases, the posterior approach (Southern or moore approach) was used, with the patient placed on the contralateral side.

Post Operative Protocol: The hip is positioned in approximately 15 degrees of abduction while the patient is recovering from the anesthesia using a triangular pillow to maintain abduction and long knee brace to prevent extremes of flexion. First post op day, check X-rays are taken. The patient is taught static quadriceps exercises, knee and ankle mobilization exercises and made to sit. On Second post op day drain was removed and dressing done and physiotherapy started. IV antibiotics were given for 48 hours later switched over to oral antibiotics for further 5 days more. On 13^th post op day sutures are removed and patient was discharged from the hospital to be reviewed after 4 weeks. At the time of discharge, they were advised to not to squat, not to sit cross legged, not to use Indian toilets, and to not to cross the lower limb across the midline. The patients were followed up at 6 weeks, 3 months, 6 months, 1 year and at yearly intervals. Patient follow up was for a minimum of 6 months to a maximum of 30 months (2 and a half years). The clinical and functional outcomes were evaluated by modified harris hip score. Based on a total of 100 points possible, each question is awarded a certain number of points. Questions are further grouped into categories. The score is reported as 90-100 for excellent results, 80-90 being good, 70-79 fair, 60-69 poor, and below 60 a failed result. A radiograph was taken at the end of the procedure and during follow up visits. The standard radiograph was an anteroposterior view of pelvis including both hips and sufficient length of femur. The radiological assessment included positioning and alignment of the acetabular and femoral components and complications such as periprosthetic fractures, loosening, osteolysis, dislocation, subsidence and heterotrophic ossification.

Preoperative problems like protrusio acetabuli was seen in 5 hips and fixed flexion deformity is seen two patients. Intraoperative problem like periprosthetic fracture was seen in one patient. Postoperative complication like limb length discrepancy was seen in 6 patients, foot drop in one patient, posterior dislocation of hip in one patient, superficial infection in 2 patients, deep infection in one patient and periprosthetic fracture in one patient. Protrusio acetabuli is a central acetabular defect resulting from migration of femoral head medially. This results in medialization of the center of rotation of the hip. Primary uncemented total hip replacement (THR) in such situations can be technically demanding due to associated significant medial and proximal migration of the center of the joint, deficient bone medially and reduced bony support to the acetabular component peripherally. Cemented total hip arthroplasty resulted in promoting bone lysis and implant loosening.

Limb-length discrepancy can result from a poor preoperative patient evaluation as well as intraoperative technical errors with regard to the level of resection of the femoral neck, the prosthetic neck length, or the failure to restore offset. Up to one centimeter shortening or lengthening can be compensated by pelvis. More than 1 cm discrepancy can be treated by shoe raise on other side.

Sciatic nerve palsy in form of EHL weakness/ foot drop was seen in one patient. The patient recovered in 6 months; all is needed that reassurance. Nerve conduction studies and EMG are needed, if there is no recovery in 6 months. In certain cases, early surgical exploration and release of nerve is indicated.

Figure 7: Periprosthetic fracture treated by SS wiring

Figure 8: Distal femur peri prosthetic fracture treated by long term immobilization

Figure 9: Posterior dislocation of hip treated by close reduction

Table 3: Cause of AVN distribution of the cases

Table 4: Pre operative problems

Table 5: Intra operative complications

Out of 50 cases, in one case develop Fracture Proximal femur- periprosthetic, in one case develop peri prosthetic Fracture shaft femur and 48(96.0%) had no intra operative complications

Table 6: Post operative complications distribution of the cases

Out of 50 cases, 6(12.0%) cases had limb length discrepancy post operative complication, 3(6.0%) had superficial infection, 1(2.0%) Anterior thigh pain, 1(2.0%) Deep infection, 1(2.0%) EHL weakness, 1(2.0%) Peri-prosthetic fracture and in 37(74.0%) cases no post operative complications.

Table 7: Pre and post operative mean scores comparison

Table indicate that, post operative mean pain score 41.48±4.71 was significantly higher as compare to pre-operative pain score 13.40±4.79 with p<0.05. Post operative mean Function-Gait score 30.74±2.16 was significantly higher as compare to pre-operative Function-Gait score 22.56±3.48 with p<0.05.

In the study by Kakaria et al, there were 20 patients and out of which there were 16 males and 4 females. The overall male to female ratio was 4:1. Majority of patients were between 31-40 years (45%) and 41-50 years (25%), which had similar distribution of age groups like our study ⁽¹⁵⁾. In our study the analysis of patients for the etiology of AVN showed that in 43 (86%) of the patients developed AVN oh hip joint the cause was idiopathic, 5 (10%) of patients developed AVN secondary to corticosteroid use, and secondary to post trauma 2 (4%) patients developed AVN of the hip joint. In a study by Koo and Kim et al showed 65% of AVN due to idiopathic cause and 10% to 30% cases due to corticosteroid therapy which is quite similar to our study ⁽¹⁶⁾. The Harris hip score is the most commonly used scoring system for evaluating hip replacement. We used Harris hip score to assess the functional outcome in our study. Excellent results are seen in 43 (86%) cases, good results are seen in 6(12%) cases, Fair result is seen in 1 (2%) case and poor results are seen in none case. The mean Harris Hip Score during preoperative period was 52.84 and during post operative stage was 94.09. Almost similar results are seen in other studies ^{(11-14,16,17,18)}. Bourne et al ⁽¹⁹⁾, in a study of 101 total hip replacements with the uncemented (porous-coated anatomic) prosthesis, reported an average Harris hip score of 96 points, but only patients who were free of pain were evaluated. When patients who had pain were included, the overall average score was 90 points. Heekin et al ⁽²⁰⁾ reported an average score of 93 points after a minimum of five years of follow-up of 91 hips that had been treated with the non-cemented prosthesis. In a study by Katz et al⁽²¹⁾, the results of 14 arthroplasties, in which the stem had been fixed without cement, the hip score averaged 84 points at forty-six months. Barrack and Lebar ⁽²²⁾ reported an average Harris hip score of 93 points after 49 arthroplasties in which the Uncemented prosthesis had been used.

The study by Mullaji et al (29) suggests that the use of impacted morsellised autograft in conjunction with porous coated cementless acetabular component restored hip biomechanics after an intermediate duration follow up. 30 primary THR’s were conducted with a 4.2 year follow up which showed excellent outcome in 90% patients, fair in 7 % patients and poor in 3% patients. A study by Mohanty et al (30) showed that using only cement for acetabular reconstruction in protrusio acetabuli has had unacceptably high rates of recurrence, with components migration into the acetabulum and occurrence of thermal necrosis of the thinned out medial wall due to heat polymerisation of the cement. Uncemented THR with morsellised autograft in Protrusio acetabuli with AVN hip produces good results. It helps in restoring biomechanics of hip joint and preventing recurrence of protrusio. There was no evidence of progression of protrusio or socket loosening or osteolysis in any of our cases. Our results are comparable to the results of other studies. But a larger sample size and a longer follow up is required to ascertain this fact. Pre operative problem like fixed flexion deformity of hip is seen in 2 patients. Management of fixed flexion deformity of hip is done by removal of all the osteophytes from anterior side of acetabulum, release of the pericapsular adhesions of hip joint, elongation of Iliopsos tendon by sequential cutting, release of TFL distally from Gluteus Medius insertion and adductor tenotomy,

The outcome of THR of hip joint is determined by the design of component, the selection of the patients, and the operative technique.

The outcome of the THR is determined by the design of component, the selection of the patients, and the operative technique. The results of the procedure needs long term studies for evaluating the complete effect. Current generation of uncemented implants provide satisfactory clinical and radiographic outcomes in intermediate duration of follow up. Even though the procedure is not free of complications, the overall functional and clinical outcome had shown good to excellent result. In future, cases of AVN hip may increase because of excessive use of steroids in covid 19 treatment.

References