Osteoarthritis is one of the most common disabling diseases of old age with prevalence of 22-30% in Indian population. ¹ Incidence of osteoarthritis is on rise because of changes in lifestyle, increase in longevity of the population, and obesity. The increase in prevalence of osteoarthritis suggests that this disease will have a significant impact in the health care and public health system.

Although various treatment options are available for osteoarthritis, which range from conservative treatment like medical therapy, physiotherapy, intra articular injections with steroids, biologicals like PRP or bone marrow aspirate to operative treatments like knee debridement, high tibial osteotomies, interpositional arthroplasty and surface arthroplasties, total knee arthroplasty provides a reliable and better results in Kellger Lawrence grade IV Osteoarthritis knee.

Various types of prosthetic designs and surgical approaches for total knee replacement were proposed and executed. So, it became necessary to conduct studies for assessing the outcome of various prosthesis &approaches for knee replacement. It can be measured by the Knee Society Scoring system. The Knee Society Score System is subdivided into two, a knee scores that rates only knee joint itself, a functional score which rates patient’s ability to walk and stair climbing. This eliminates problem of decreased knee scores associated with infirmity of patients.

This study aims to evaluate the functional outcome of total knee replacement in grade IV osteoarthritis treated with standard medial parapatellar approach and posterior stabilized prosthesis using the knee society score and WOMAC score.

This is a prospective study conducted in department of orthopaedics NRIIMS, Visakhapatnam, during period of July 2022 to June 2024. After taking clearance from institutional ethics committee, A total of 25 patients with KL grade IV OA knee were included in this study.

Inclusion Criteria:

• Both male and female patients of age between 50 to 85 years with K-L grade IV osteoarthritis having disabling knee pain even after failed conservative treatment.

• Patients with intact medial and lateral collateral ligaments.

Exclusion Criteria

• Patients With Rheumatoid arthritis/ Inflammatory arthritis.
• Patients with local or systemic infections and any neurological deficit.

Patients who fulfilled the above criteria were evaluated clinically, radiologically to ascertain the need for surgery and fitness to undergo the procedure. Informed consent is taken from the patients to participate in the study. All patients were treated with the same category of medication, similar anesthesia (combined spinal and epidural anesthesia), and intraoperative technique with standard medial para patellar approach and PS(posterior stabilized) knee of same company. All the subjects were evaluated preoperatively and postoperatively at follow-ups on post-operative day 14 to16, at 1 month, 3 months, 6 months, and 12 months to monitor recovery and progress using the Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Final scores at end of 12 months and pre-operative scores were compared in this study

In this study 12 patients (48.0%) were in the age group of 51-60 years, 11 patients (44.0%) were in the age group of 61-70 years, and 2 patients (8.0%) were older than 71 years. With youngest being 51 years and eldest being 78 years and mean age group is 61.68 years. Out of 25 patients who underwent total knee replacementt 11 were males and 14 were females

Out of 25 patients, 11 patients (44.0%) had the surgery on the left knee, while 14 patients (56.0%) had the surgery on the right knee. In this study even though patients have symptoms in opposite knee, the knee with only grade 4 osteoarthritic changes and significant disability was taken to consideration. The BMI distribution was as follows: 2 patients (8.0%) were underweight, 7 patients (28.0%) had a normal BMI, and 16 patients (64.0%) were overweight. Mean BMI of 24.64. Baesd on duration of symptoms, 4 patients (16.0%) had disease symptoms of less than 5 years, 8 patients (32.0%) had disease duration between 5 to 10 years, and 13 patients (52.0%) had been suffering from the disease for more than 10 years. Mean duration of symptoms being 9.4 years.

Distribution of patients based on pre operative and post operative KSS (knee score)

Table 1: Distribution of patients based on pre-operative and post-operative KSS (knee score)

The study evaluated the knee scores of patients before and after total knee replacement surgery using the KSS (knee score). The preoperative KSS (knee score) had a mean of 32.60 with a standard deviation (SD) of 5.12, while the postoperative KSS (knee score) had a significantly improved mean of 85.96 with an SD of 4.29. The T-test value was -49.91, with a P-value of 0.001.

Distribution of patients based on pre-operative and post-operative KSS (functional score)

Table 2: Distribution of patients based on pre-operative and post-operative KSS functional score

The study assessed the functional scores of patients before and after total knee replacement surgery. The preoperative KSS functional score had a mean of 32.20 with a standard deviation (SD) of 3.90, while the postoperative KSS functional score significantly improved to a mean of 85.28 with an SD of 5.02. The T-test value was -45.57, with a P-value of 0.001.

Distribution of patients based on pre-operative and post-operative WOMAC

Table 3: Distribution of patients based on pre-operative and post-operative WOMAC

The study evaluated the WOMAC scores of patients before and after TKR. The preoperative WOMAC score had a mean of 84.68 with a standard deviation (SD) of 4.80, indicating a high level of pain, stiffness, and functional limitations. Postoperatively, the WOMAC score significantly improved to a mean of 15.76 with an SD of 3.59, reflecting substantial relief in symptoms and functional enhancement. The T-test value was 70.97, with a P-value of 0.001. Among these 25 patients, 23 (92.0%) experienced no complications. 2 patients(8%) had post-operative residual stiffness this is due to persistence of residual FFD in one patient, the other patient has FFD of 10 degree & decreased flexion range from 10-90 degree.

The majority of the patients, accounting for 92.0%, were between 51 and 70 years old, with mean age group of 61.68 years indicating that severe osteoarthritis requiring surgical intervention is most prevalent in this age range. Only small proportions (8.0%) of the patients were above 71 years, which could suggest either a lower incidence of patients opting for surgery at an older age or potential exclusion due to other health factors. This age distribution underscores the importance of focusing on middle-aged to early elderly populations in managing advanced osteoarthritis. Nguyen et al² found that patients aged 65-74 years had the highest rates of total knee replacement. Kundu IK et al³ reported that the average age for knee replacement patients was around 60 years, with a trend towards younger patients over time.Jeyaraman M et al⁴ found that patients mean age of around 54years in stage 4 osteoarthritis were the most frequent recipients of knee replacement surgeries.

The gender distribution of 11 males (44.0%) and 14 females (56.0%), in this study population indicates a slightly higher prevalence of severe osteoarthritis necessitating surgical intervention among females compared to males. The increased incidence of osteoarthritis around the time of menopause suggest the development of OA is linked with menopausal withdrawal of ovarian hormones⁵.Similar findings were shown in studies conducted by Patil J et al⁶ with male and female ratio 1:1.66 showing females having higher rate of getting total knee replacement for osteoarthritis.Kundu et al³ showed that women have a higher risk of developing severe osteoarthritis, leading to knee replacement, compared to men with ratio of 1:1.5 .Oliveria⁷ showed that the incidence of severe osteoarthritis, requiring surgical intervention, is higher in women than in men.

Among 25 patients, 11 patients (44.0%) had the surgery on the left knee, while 14 patients (56.0%) had the surgery on the right knee. This distribution shows a slightly higher incidence of severe osteoarthritis requiring surgical intervention on the right knee compared to the left knee. Even though most of the patients have pain in opposite knee or early grade osteoarthritis we have considered the knee with grade 4 osteoarthritic changes and greater symptoms. Understanding the side predominance in knee osteoarthritis can be useful for clinicians in diagnosing and planning treatment strategies.Shakoor et al⁸ Found that the dominant leg is more prone to osteoarthritis due to greater mechanical stress and repetitive movements.Hart et al⁹ reported that the dominant knee (right knee in right-handed individuals) is often more affected by osteoarthritis due to higher load and activity levels.Eckstein et al¹⁰ indicated that the higher incidence of right knee osteoarthritis may be related to biomechanical factors associated with limb dominance.

In this study, BMI distribution was as follows: 2 patients (8.0%) were underweight, 16 patients (64.0%) had a normal BMI, and 7 patients (28.0%) were overweight. The majority of the patients, 64.0%, had a normal BMI, indicating that severe osteoarthritis requiring surgical intervention can occur across a range of BMI categories but is most prevalent in those with a normal BMI. However, a significant portion of patients (28.0%) were overweight, suggesting that higher body weight might contribute to the severity of osteoarthritis. Similar findings were documented by Kundu et al³  , Patil J et al⁶ and jeyaraman et al⁴ in their studies. Anandacoomarasamy et al¹¹ found a strong association between obesity and the development of knee osteoarthritis, indicating that higher BMI is a significant risk factor.Jiang et al¹² showed that patients with higher BMI have a greater risk of developing severe knee osteoarthritis and undergoing knee replacement surgery.Messier et al¹³ Indicated that obesity significantly increases the risk of knee osteoarthritis and that weight loss can reduce symptoms and delay the need for surgery.Cooper et al¹⁴ found a strong link between obesity and the risk of knee osteoarthritis, suggesting that overweight individuals are more likely to undergo knee replacement.Murphy et al¹⁵ Indicated that obesity is a major risk factor for the development and progression of knee osteoarthritis, leading to a higher need for surgical intervention.

In this study, 4 patients (16.0%) had disease symptoms of less than 5 years, 8 patients (32.0%) had disease duration between 5 to 10 years, and 13 patients (52.0%) had been suffering from the disease for more than 10 years. The majority of the patients, 52.0%, had been living with osteoarthritis for more than a decade, indicating that the progression to severe osteoarthritis requiring surgical intervention typically occurs after a long duration of the disease. A substantial portion of patients (32.0%) had the disease for 5 to 10 years, while only a small percentage (16.0%) had the disease for less than 5 years. These findings suggest that the severity of osteoarthritis that necessitates total knee replacement is often a result of prolonged disease duration, emphasizing the chronic and progressive nature of osteoarthritis.Loeser et al¹⁶ found that the progression to severe osteoarthritis and the subsequent need for knee replacement surgery are strongly associated with the duration of the disease.Murphy et al¹⁵ found that the likelihood of requiring knee replacement increases with the duration of osteoarthritis, with most patients requiring surgery after having the disease for over 10 years.Bijlsma et al¹⁷ indicated that longer disease duration is associated with more severe symptoms and a higher likelihood of undergoing knee replacement.Zhang and Jordan¹⁸ reported that the duration of osteoarthritis is a critical factor in the progression to severe disease and the need for knee replacement, with longer durations associated with worse outcomes.

KSS (KNEE SCORE)

This study evaluated the knee scores of patients before and after total knee replacement surgery using the Knee score. The preoperative KSS (knee score) had a mean of 32.60 with a standard deviation (SD) of 5.12, while the postoperative KSS(knee score) had a significantly improved mean of 85.96 with an SD of 4.29. The T-test value was -49.91, with a P-value of 0.001. This significant increase in KSS (knee score) from preoperative to postoperative assessments (P < 0.001) indicates a substantial improvement in knee function and overall patient outcomes following total knee replacement. The results demonstrate that the surgery is highly effective in enhancing knee functionality for patients with grade IV osteoarthritis.Similar findings were observed by Jeyaraman et al⁴ in his study where he observed significant improvement in KSS (knee score) pre op score 57.3 and post op 97.4.Dasgupta S et al¹⁹ in his study to review outcome of total knee replacement in osteoarthritis knee observed significant improvement in mean knee society score (knee score) from 27.4 pre operatively to 81 post operatively.Shihora et al²⁰ also observed similar improvement in knee society score (knee score) from 49.4 to 86.08 post operatively.

KSS (FUNCTIONAL SCORE)

This study assessed the functional scores of patients before and after total knee replacement surgery. The preoperative functional score (KSS) had a mean of 32.20 with a standard deviation (SD) of 3.90, while the postoperative functional score (KSS) significantly improved to a mean of 85.28 with an SD of 5.02. The T-test value was -45.57, with a P-value of 0.001. This significant increase in functional scores (KSS) from preoperative to postoperative assessments (P < 0.001) highlights a dramatic improvement in the functional abilities of patients following total knee replacement. The results clearly indicate that the surgical intervention significantly enhances the functional outcomes for patients with grade IV osteoarthritis, contributing to a better quality of life and greater independence in daily activities.Jeyaraman et al⁴ in his study where he observed significant improvement in functional score (KSS) pre op score 36.3 and post op 85.2.Dasgupta S et al¹⁹ observed significant improvement in mean functional score (KSS) from 30 pre operatively to 79.3 post operatively in his study. Shihora et al²⁰ also observed similar improvement in functional score (KSS) from 32.75 to 84.43 post operatively. Bourne et al²² also found that functional score (KSS) improvement from 34 to 87.

Western Ontario and Mcmaster Universities Osteoarthritis Index (Womac) Scores

This study evaluated the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores of patients before and after total knee replacement surgery. The preoperative WOMAC score had a mean of 84.68 with a standard deviation (SD) of 4.80, indicating a high level of pain, stiffness, and functional limitations. Postoperatively, the WOMAC score significantly improved to a mean of 15.76 with an SD of 3.59, reflecting substantial relief in symptoms and functional enhancement. The T-test value was 70.97, with a P-value of 0.001. This significant decrease in WOMAC scores from preoperative to postoperative assessments (P < 0.001) demonstrates a considerable reduction in pain and improvement in joint function following total knee replacement. The results highlight the surgery's effectiveness in alleviating the symptoms of severe osteoarthritis and improving patients' overall quality of life. Heleder et al²² in his study had significant improvement in womac scores from 62.52 to post op 24.24 co releating to our study.TL Kahn et al²³ in his study had similar improvement in WOMAC scores after total knee replacement from a pre operative score of 35 to post operative 12.6.In our study higher pre op WOMAC scores were observed. This can be due to inclusion of only grade IV knee osteoarthritis patients who had significant pain and disability in our study.

In this study, 23 (92.0%) experienced no complications, indicating a high success rate and favorable outcome for the majority of the cohort. However, 2 patients (8.0%) developed postoperative stiffness, this is due to persistence of residual FFD in one patient whose pre-operative rom is significantly low, the other patient had residual FFD of 10 degree and decreased flexion range from 10-90 degree only this may be due to pre-operative FFD, pre op decreased rom and poor adherence to the post op rehab protocol. Other complications like Infections, delayed wound healing etc. were not seen in this study as the patients who underwent this study were medically fit and having only primary osteoarthritis, patients with other conditions like rheumatoid arthritis on DMARDs and long term medications were excluded. This highlights a potential area for postoperative care and rehabilitation. The overall low complication rate demonstrates the effectiveness and safety of total knee replacement surgery in managing severe osteoarthritis, with postoperative stiffness being the most notable complication to monitor and address. Kundu et al³ Found that the overall complication rate in total knee replacement surgeries ranged from around 10% with postoperative stiffness being a significant issue. Chetan et al²⁴ in his study observed 2 complications out of 34 patients of tkr with complication rate of 5.8% with complications stiffness and post op infection.Dasgupta et al¹⁹ in his study to review outcome in tkr in osteoarthritis found the complication rate of 5%.

Postoperative results revealed a high success rate and the substantial improvements in Knee Society Scores (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores highlight the effectiveness of total knee replacement in enhancing knee function and alleviating symptoms. The usage of two scoring systems increase the reliability of the study and limits the confounders. These findings affirm that total knee replacement is a highly effective surgical intervention that significantly improves functional status, pain relief, and overall quality of life for patients suffering from severe osteoarthritis.

Conflict of Interest: None

Funding Support: Nil

LIMITATIONS

The study was conducted on a relatively small sample size of 25 patients, which limits the generalizability of the findings. Larger studies are needed to validate these results across diverse populations. The follow-up period in this study was limited to 12 months. Longer follow-up periods are necessary to assess the durability of the surgical outcomes and the long-term effectiveness of total knee replacement. The study relied on patient-reported outcomes such as the WOMAC and Knee Society Scores, which are subjective measures. Objective assessments such as gait analysis or functional performance tests could provide additional insights into postoperative improvements.

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