Hip fractures are devastating injuries that most often affect the elderly population and have a tremendous impact on the health care system and the society in general. It has been shown that hip fractures occur a decade earlier in Indians in comparison with western Caucasian counterparts. The life expectancy at birth in 2010 was 65.1 years for Indian and as it shows an upward trend, increasing proportion of our population would face these problems. Osteoporosis, co-morbidities, increased incidence of trivial trauma increases the incidence and complicates the treatment of these fractures. This high incidence is due to weak bones and increased incidence of trivial trauma. People in this age group suffer from numerous illnesses that can aggravate the morbidity following fractures and complicate the treatment of these fractures. The treatment goal is to return the patient to his or her pre-morbid status of function. Increase in the average lifespan and improved medical facilities have greatly increased the incidence of these fractures. More over the awareness of osteoporosis in India is poor and the screening facilities for identifying is poor. Management of femoral neck fractures in elderly patients has been controversial. Femoral neck fractures have been considered 'unsolvable fractures' in the older era of orthopaedics1 due to the high rate of associated complications, which include nonunion, lack of rigid fixation and avascular necrosis of the femoral head, among others. Presently, there are multiple surgical treatment options (cannulated screws, dynamic hip screw systems, blade plates, hemi and total hip arthroplasty) available. Intracapsular extent of the fracture, tenuous blood supply to the femoral head going through the neck and difficulty in maintaining fracture reduction have been cited as reasons for failure of fixation. Although treatment methods have been refined over the years, a consensus on the ideal treatment remains elusive.[1,2]

Important factors to consider in choosing any treatment modality are intrinsic, viz. patient age, general medical condition, type of fracture; and extrinsic, viz. availability of facilities and socio-economic status. Though non-operative treatment of these fractures has been documented, there are currently very few indications for the same (being limited to terminally ill patients or those who are bedridden and non-ambulatory). Surgical treatment has been established as the gold standard; however, the surgical option remains a dilemma. Open reduction and internal fixation has been shown to have a high rate of revision surgery due to nonunion and avascular necrosis Hip replacement arthroplasty (partial or total) is emerging as the most viable treatment option.

Orthopaedic surgeon in India (also in other developing countries) has to treat patients from different economic strata from very rich to a very poor person who may not be able to afford even one meal a day. Majority of the patients have no health insurance and have to pay from their own pocket. Government resources are limited and can at the most subsidize the treatment. The life style of the patients requiring them to squat or sit in Buddha position makes it desirable to preserve the patients own hip joint. The range of movements at the Hip required to adopt these postures are neither possible nor permissible in any artificial joint available at present. Quite often the patients report late for treatment may be after many weeks or even months when internal fixation alone has high failure rate.

Replacement arthroplasty (total hip arthroplasty, bipolar prosthesis and hemi-arthroplasty) are very useful procedures and have to be carried out when it is not possible to achieve union of fracture or in old people who have to be put on their feet without loss of time. These procedures have to be offered to those who can afford and are capable of modifying their life style so that the artificial joint lasts for longer period. Prosthetic replacement allows immediate weight bearing to return elderly patients to activity and help avoid complications of recumbency and inactivity. When the concept of prosthetic replacement was first introduced, this perhaps was the most important advantage.

As a primary procedure, prosthetic replacement eliminates osteonecrosis and nonunion as complications of femoral neck fractures. There still is no completely reliable way of identifying femoral heads with a significantly damaged blood supply before definitive surgery. Developing technology may allow definitive preoperative identification of these avascular femoral heads and provide useful information in making the decision between prosthetic replacement and internal fixation.[3,4]

Prosthetic replacement of displaced femoral neck fractures reduces the incidence of re operation compared with internal fixation. This argument applies only to elderly individuals with a limited life expectancy because the cumulative rate of re operation for prosthetic replacement increases with time. The decision to perform hemi arthroplasty using a unipolar or bipolar prosthesis remains controversial, with proponents on either side. Advantages of the unipolar prosthesis include lower cost and no risk of polyethylene wear debris. Proposed advantages of the bipolar prosthesis include less acetabular wear and potentially less hip/groin pain. The choice between unipolar and bipolar prostheses is less clear. The main theoretical advantage of a bipolar over a unipolar prosthesis is the reduction of acetabular erosion due to movement taking place within the implant rather than between the head of the prosthesis and the acetabulum, although there is variation in the comparative distribution of the movement. Movement within the prosthesis may also reduce the pain caused by the prosthesis moving against the acetabulum.

It is a Comparitive, Prospective study between Austin Moore prosthesis and Bipolar prosthesis in Fracture neck Femur‖-A Prospective Comparitive Study was conducted at Government medical college, Mancherial, in the period from January 2022 to December 2023, in all Male\Female patients aged 60 or more admitted in the hospital. 52 elderly patients who were admitted had fulfilled the inclusion criteria, were enrolled for this study. Patients operated with Austin Moore‘s prosthesis were allocated to Group A and operated with Bipolar Prosthesis were allocated to Group B. 26 patients each were allocated into 2 groups A and B according to randomized tables. 3 patients from group A were lost to follow up. 1 from group A died. 48 patients who completed follow up till one and half year postoperatively were included in this study.

Inclusion Criteria: Cases of fracture neck Femur of Age group above 60 years in all patients medically fit for surgery even with hypertension and diabetes mellitus in all types of fractures under Gardens Classification are considered in Closed Fracture within 3 weeks.

Exclusion Criteria: Seriously ill patients and Pts not fit for surgery, Fracture due to tumour or any other pathological cause, Compound Fractures, Other limb fractures and diseases, Neurovascular injuries

In this study primary hemi replacement arthroplasty of hip is done in 52 cases of fracture neck of femur, using bipolar prosthesis for 26cases and Austin Moore‘s Prosthesis for 26 cases. The operative procedure is meticulously followed; the results are evaluated and compared.

Preoperative Management

Patients were admitted to the ward. Detailed history was taken with particular emphasize on mode of injury and associated medical illness. In depth, clinical assessment was carried out in each case.

Routine blood investigations, blood grouping and typing, urine routine, RBS, serum urea, creatinine, HbsAg, HIV, chest x-ray, ECG, 2D ECHO were done in all cases.

Postoperatively patient is kept in recovery room for 3 hours later shifted to post-operative ward for 24 hours. IV fluids given. After 6 hours oral fluids are given. Intravenous antibiotics were continued for 5 days.  In case of spinal anaesthesia, foot end elevation was given depending on the patients postoperative blood pressure.  Every half an hour blood pressure, pulse rate, temperature, and respiratory rate were monitored for the first 24 hours. Whenever necessary, postoperative blood transfusion was given Intramuscular analgesics were given as per patient‘s compliance. Buck's skin traction was continued for 24 hours with both the lower limbs kept in abducted position, with a pillow in between both the legs. Drain removal was done after 48 hours. Check radiograph was taken after 48 hours. After 24 hours, Position of patient is changed once in 3 hours with pillows kept between the legs.  Exercises like deep breathing exercises, quadriceps exercises and movements are taught.  Patients were made to sit up on the second day, standup with support (walker), third day, and were allowed to full weight bear and walk with the help of a walker on the fourth postoperative day depending on his/her pain tolerance and were encouraged to walk thereafter. Sitting cross-legged and squatting were not allowed.  Suture removal was done on the twelfth postoperative day. The patients were assessed for any shortening or deformities if any and discharged from the hospital. Patients who had infection and bedsores were treated accordingly before discharging them from the hospital. Patients were followed up at an interval of 6 weeks, 3 months, 6 months and one year. Functional outcome was analyzed by modified Harris hip scoring system. At each follow up radiograph of the hip was taken for radiological analysis. At the time of discharge the patients were asked to come for follow up after 6 weeks and for further follow up at 3 months, 6 months and one year. The patients who turned for follow up or whose details could be collected were finally taken up for the assessment of functional results.

At follow up, detailed clinical examination was done systematically. Patients were evaluated according to Harris hip scoring system for pain, limp, the use of support, walking distance, ability to climb stairs, ability to put on shoes and socks (in our study for some patients ability to cut toenail was enquired) sitting on chair, ability to enter public transportation, deformities, leg length discrepancy and movements. All the details were recorded in the follow up chart. The radiograph of the operated hip was taken at regular intervals, at each follow up. Harris Hip Scoring System: Formulated by W.H.Harris. It incorporates all-important variable into single reliable figure, which is both reproducible and reasonably objective.

Harris Hip Score -Interpretation

90-100 -excellent results,

80-89 - good,

70-79- fair,

60-69 -poor, and

Below 60- a failed result

During each follow up functional outcome measured according to Harris hip score and clinico radiological assessment was done. The Harris Hip scores were analyzed and compared statistically using Chi square test and Fischer ̳t ̳test at follow up of 3 months, 6 months and 1 year.

Table 6 –Age Incidence

Out of 52 cases enrolled in the study 3 cases from Group A were excluded from the study as they were lost to follow up and 1 patient died due to Chronic Kidney disease. So at the end 48 patients finished the study with 22 in AMP group and 26 in Bipolar group. Of the 48 patients 28 were females and 20 were males. The youngest patient in our series was 60 years old and the oldest patient was 91 years old. The average age of the patient in group A was 69.1 years and in group B was 70.4 years. In our study Group A patients were mobilised on an average of 4.04 post-operative day whereas Group B were mobilised on 3.76 post op day.

Table-2: Association of Age Group with Outcome

This study signifies that with age group ranging 60 –70, 92.9% of the cases in Group A had Excellent to good outcome which was more compared to 86.7% of the cases in Group B, but the difference was insignificant. Age group ranging from 71- 80, 83.3% of the cases in Group A had excellent to good as their outcome which was less compared to 100% results in Group B. Whereas age group belonging to >81years, 50.0% of the cases in Group A had excellent to good outcome which was less compared to 100% in Group B, but the difference was not significant.

Table-3: Association of Outcome with Sex

In our study 27.2% of male patients in group A had excellent to good results which was less compared to 54.5% of females with excellent to good results, but the difference was statistically insignificant.(p=0.2129). Similarly, in Group B both males and females had 96.7% excellent to good results. (p=0.549). In our study the average post op days in Group A is 14.9 and in Group B is 13.3.  In our study 43mm was the most commonly used prosthesis in Group A whereas 41mm was the most commonly used prosthesis in Group B.

Table-4: Post op Mobilisation

The patients walked (partial weight bearing) on an average 3.64 days after surgery.

2 patients in group A and 3 patients in group B developed superficial infection. All of them settled with IV antibiotics according to culture and sensitivity.5 people developed haematoma probably due to early removal of drain. Deep seated infections were seen in 2 patients in Group A and 1 patient in Group B. Acetabular erosion was noted in 2 patients of Group A, there were no incidences of posterior dislocation or peri prosthetic fractures in our study.

Table-5: Assessment of functional results

The patients were enquired about the kind of pain they experienced during their daily activity and recorded according to the grades and scores.73.1% of Bipolar Group and 40.1% of AMP Group had no pain. The difference in pain is statistically significant with a p value=0.0095.

All the patients the study were enquire about the distance that they are able to walk and recorded and graded accordingly. 65.4% of Bipolar group were able to walk unlimited and 45.5% of AMP group were able to walk unlimited. Difference in distribution of distance walked is statistically insignificant. (p=0.2592). 68.9% of patients in Group AMP wore shoes with difficulty where as 53.9% of patients in Group Bipolar wore shoes with difficulty. Wear shoe and socks is easy in Group B but the difference is statistically insignificant.(p=0.0995). 69.23% of bipolar group were able to use the public transport compared to only 54.5% of AMP group, and the difference is statistically significant {p=0.0452 (Fischer t test)}

Table-6: Use of support

In our study, 50.0% of Bipolar group used no support for walking whereas 31.8% of AMP group used no support for walking. None of the cases used two canes. The difference is statistically insignificant. (p=0.4000)

Table-7: Ability to climb Stairs and sit

All patients analyzed for the ability to walk stairs and scored accordingly. 61.5% of Bipolar group climb with help of support and68.8% of AMP Group can climb with the help of support. Distribution of ability to climb stairs with or without support is statistically insignificant. (p=0.4251). In our study 59.09% patients in group A were able to sit for more than an hour which was less when compared to 80.8% in Group B, but the difference was statistically insignificant{p=0.1219(Fischer t test)}

Table-8: Radiological Assessment

At the end of 6 months all patients X-ray was taken and assessed

Table-9: Complications

We noticed acetabular erosion in 2 cases in AMP group.

The average age of the patient in group A was 69.1 years and in group B was 70.4 years. Majority of the patients were between 60-70 years. The physiological age of our patients is more than the chronological age in all our patients.  The elderly females are more prone to fracture neck of femur. Female preponderance has been reported in several series John E. Kenzora [5] 77.4%, Carl Johan Hedbeck [7] 76%, Bhushan MS [8] 78.5%. Male femoral neck fracture patients are in general younger than female patients. In our study female preponderance was 65.8%. [9] Left sided hip was fractured in 60.9% of our cases. 65% of bipolar group and 57.1% of AMP were left sided fracture. In our study we reported 63.6% right sided fractures in Group A and 53.8% in group B.

Depending on the anteroposterior view in internal rotation the fracture pattern is classified among Garden type 1 to 4. Majority of the fractures in our study belong to types 2 and 3 59.1% in Group A and 53.8 % in Group B. The types of displacement (Gardens III and IV) are not taken as the criteria to choose the procedure for the management of fracture neck of the femur. The age of the patient are taken into consideration while selecting hemiarthroplasty for the management of fracture neck of femur. 100.0% of our patients had trivial trauma (self-fall). This is in accordance with majority of the series reported and several other authorities believe that the intracapsular fracture are stress fractures through pathological bone secondary to osteoporosis or osteomalacia. We had no operative deaths in our series. Totally 1 patient (4.5%) expired during the follow in our series, from Group A. The death was due to Chronic Kidney disease.

Table-11: The following are the studies showing mortality rates.

Nather et al[15] reported on a series of 110 patients with mean age of 78 years, treated by unipolar, found a one year mortality of 15%. Su et al[16] reviewed the in-hospital mortality rates of patient‘s age greater than 65 years. They reported greater than 50,000 patients and found overall mortality rate of 5.6%. Clyer and Bruckner[17] found mortality rates of 22%,63% and 81% at 1, 5 and 10 years after hemi arthroplasty using AMP. Nottage et al[18] showed mean age, 65 years; mortality, 11%.

In our series, all the patients were discharged after the patient is trained for active mobilisation and when fit were for discharge. Most of our patients, 57.7% of Bipolar and 54.5% of AMP group stayed between 10-15 days. But 19.2% of Bipolar were discharges within 10 days because of their active recovery when compared to 13.6% in AMP group. Post-operative stay is statistically similar.  According to Cornell[19] there was no differences in the postoperative complication rates or lengths of hospitalization were seen between the two groups. All our patients were mobilised as early as possible depending on patient compliance. Most of the patients were mobilised within 3 days in both groups, 61.5% in bipolar and 63.6% in AMP.  Two patients (9%) from AMP group when followed up to one year presented with painful hip and acetabular erosion. Shortening of 2 cm was noted and gross restricted range of motion was observed, thereby limiting his functional activity. It was classified as grade 2 in both cases, according to Baker.

Baker et al[20] reported acetabular erosion in 21 out of 32 patients treated with a unipolar HA after a mean follow-up of 39 months, giving an overall rate of acetabular erosion of 66%.Acetabular erosion occurs as a result of impact causing injury to the acetabular cartilage at the time of the accident, especially as the elderly often sustain injury by a fall directly on the hip. Excessive pressure on the acetabular cartilage after arthroplasty also produces erosion when insufficient femoral neck is resected in the anxiety to obtain a firm, stable reduction. It is felt that the exact matching of the size of the prosthetic head is particularly important, too large a head producing ring wear of the acetabulum and too small a head increased point bearing with subsequent wear. Finally, the cemented metal implant within the upper part of the femoral shaft will be more likely to transmit the impact of each footfall with greater stress across the prosthesis to bone interface than would normal bone in which there is considerable resilience. Skala-Rosenbau [21] observed that prosthesis migration depended on the position of the head, CE angle and position of the prosthetic stem in the medullary canal. The resection level of the femoral neck and resulting from it the position of the prosthetic head is a significant factor influencing the progress of acetabular erosion James and Gallannaugh [22] reported no evidence of acetabular erosion in 323 patients treated with bipolar prosthesis followed for more than 7 years. The theoretical advantage of the bipolar design was to dissipate the joint forces through the inner bearing surfaces, thereby decreasing the rate of superior acetabular erosion. Cadler [23] described acetabular erosion after hip hemiarthroplasty is a longer- term problem in younger patients. There were three cases in the unipolar group and none in the bipolar, which may demonstrate the theoretical benefit of the bipolar prosthesis, although the differences were not statistically significant. Acetabular erosion was graded according to the criteria of Baker et al. as grade 0 (no erosion), grade 1(narrowing of articular cartilage, no bone erosion), grade 2(acetabular bone erosion and early migration), and grade 3(protrusion acetabuli).     

 In our study, we had 5 cases of superficial infection, 3 (11.5%) in bipolar and 2 (9%) in AMP group. It was managed conservatively with IV antibiotics, based on the culture growth. 3 (13.6%) patients in AMP Group and 2 (7.6%) patients in Bipolar Group developed Haematoma. Some of these patients had incidents of accidental drain removal. We believe that proper suturing of drain is important for preventing haematoma. We had 3 cases of Deep infection 2(9%) in Group A and 1(3.8%) in Group B probably due to poor hygiene and uncontrolled diabetes.  Increased incidence of infection has been reported with using posterior Moore‘s approach for hemiarthroplasty. Reported incidences of superficial infection after primary prosthetic arthroplasty include. The infection was no ways related to the prosthesis. Overall, the incidence of complication rate is more noted with AMP group. In our series, 73.1% of bipolar and 40.1% of AMP had no pain. Distribution of pain is less in Bipolar group and the difference is statistically significant p=0.009. Studies showing with no pain. 80.8% of bipolar group and 59.09% of AMP group were able to sit in a chair comfortable for more than a hour. Statistically both the groups are similar with p value=0.1219. In our series, 69.2% of bipolar group were able to use public transport compared to 54.5% of AMP group (p=0.0452) and the difference was statistically significant. Maximum of our patients, 68.9% of AMP and 61.5% of bipolar group use support for climbing stairs. Statistically both the groups are similar with p=0.4251.  Mean Range of motion of bipolar was 234.6 compared to 221.3 in AMP.  Cornell et al[19]who reported that patients with bipolar prosthesis did better on walk tests and had better range of motion at 6 months. Distance walked 65.4% of bipolar were able to walk unlimited compared to only 45.5% of AMP. There was no statistical difference between the two groups (p=0.2592). Bhushan M Sabnis, Ivan J Brenkel 100 reported 14 % unipolar walking unaided compared 54% of bipolar walking alone outside.

All the cases in our series were assessed according to Harris Hip Score and graded accordingly as Excellent, Good, Fair, Poor and Failure. We got 65.3% excellent result with Bipolar group and 40.9% with AMP group. The mean HHS was 90.03 in Bipolar and 84.4 in AMP group. Distribution of result is statically similar in both groups (p=0.3283) but the mean score is statistically more associated with patients with bipolar prosthesis. Yamagata et al, in their classical study of, reviewed 1001 cases of hip hemi arthroplasty, there were 682 unipolar and 319 bipolar cases. Patients undergoing bipolar exhibited higher hip score and lower acetabular erosion rates compared to unipolar patients.

Lestrange [24] reviewed 496 patients with bipolar replacements for displaced femoral neck fractures and compared them with patients having fixed-head prosthesis. He found that the bipolar prosthesis offered advantages over one-piece designs in terms of stability, decreased acetabular erosion, and improved function.

According to Wathne [25], based on the results of this study, there does not appear to be any advantage to the use of bipolar end oprosthesis for the treatment of femoral neck fractures in the elderly patient. Calder et al [23] published the results of a study including 250 patients, all aged 80 years or more, with a 1.5–2-year follow-up. A higher proportion of patients returning to their preinjury condition was found in the unipolar HA group, but no other differences were found. In 2001, Davison et al[14] presented the results from the same study for the 187 patients aged 65–79 years with a minimum two-year follow-up. No differences between randomization groups were reported, but the interpretation is limited by the fact that 18% of the patients were lost to follow-up. According to Ong BC et al[26] there was no significant differences were found between the unipolar and bipolar groups. Finally, in Raia et al [27], reported the results of a study including 115 patients randomized to a more modern cemented unipolar HA or bipolar HA with identical stems. At the one-year assessment there were no significant differences between the groups in terms of surgical complications, functional outcome.

Table-11: The results of studies investigation.

Hence, compared to previous studies, in our study there appears to be a significant difference between the two groups functionally; better function with range of movement, use of public transport and pain, are associated better with bipolar group. And also, mean HHS is better with bipolar group.

Primary Hemi arthroplasty is an efficient way for treatment of displaced intra capsular neck of femur in elderly patients. The success of hemi arthroplasty depends on proper pre-operative planning, aseptic precautions, co-morbid conditions and attention to surgical details. At the end of 1 year the percentage of patients achieving good to excellent outcome with Bipolar prosthesis were more than those with AMP though the difference was not statistically significant.  After the end of 1 year mean Harris Hip score was 84.4 in Group A which was less when compared to 90.03 of Group B.  Incidence of complications also were more in Group A when compared to Group B though the difference was not statistically significant. The mortality, post op stay and time of mobilisation also was similar between the two groups. There was no significant radiological difference between the two groups. Comparing the functional assessment, all the parameters were similar except for use of public transport being better with bipolar group. Pain also was better in Group B when compared to Group A. Which type of hemiarthroplasty should we select for the most elderly patients with displaced fractures of the femoral neck? Based on the results of our study and previous ones, there appears to be any statistical difference between the two groups, that is bipolar being better in functional aspects. On the other hand, the results of our study showed that incidence of complication were lower after the bipolar HA, which in turn may indicate an advantage in the longer term. Some of the western literature, report that disadvantage of Bipolar being a higher cost but it was not considered in our institution, as there not much cost difference between the two prosthesis.

Limitation of the study is that the period of study is less, and sample is small number. Although an unbiased observer assessed all clinical variables except hip motion, this observer was not blinded to the type of surgical intervention, which may add a risk of bias.

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