Osteoarthritis (OA) is a Degenerative Joint Disease (DJD) which involves the cartilage and many of its surrounding tissues. In addition to the damage and loss of articular cartilage, there is subarticular bone remodeling, formation of osteophytes, ligamentous laxity, periarticular muscles weakening, and, in some cases, inflammation of the synovium. These changes may occur as a result of an imbalance in the equilibrium between the breakdown and repair of joint tissue.¹ There is no known cure for OA, so treatments are for reducing pain and other symptoms, maintain and/or improve joint mobility, and limit functional disability, with the overall management goal of improving the patients' quality of life. So far, one of the main objectives of treatment is to manage knee pain.²

Orthopedic surgeons began performing Total Knee Arthroplasty (TKA) in the 1970s. Today, it is a commonly performed surgical procedure that is beneficial to a majority of recipients and is cost effective for quality of life assessments. It is indicated for disability, pain, limited function from osteoarthritis, rheumatoid arthritis, or any type of arthritic deformity about the knee. The goals of TKA include reduction of pain, returning to activities of daily living, restoring mechanical alignment, preserving the joint line, balancing the ligaments, and restoring a normal Q angle.³

The single biggest reason to consider replacement by most patients is pain relief. Results of the larger series do show that the vast majority are pain free, or have minimal aches and pains, in the longer term. Overall, a knee replacement is not quite as pain free as a hip replacement, and it certainly does not recover as fast.⁴ This may be because the knee is relatively superficial, and not surrounded by muscle like the hip. It may also be because of the complexity of this joint in comparison to a hip. Either way, the results, at least in the short term (the first year), are not quite as good as a hip replacement. After that, however, the results do approach that of hip replacement.⁴ Managing pain after knee replacement is key for obtaining better function and earlier recovery from that surgery.

Epidural anesthesia provides very good pain relief. It  is often used as an accessory to general or regional anesthesia. Most usually, this is used when both knees are replaced at the same time. The advantage of an epidural anesthetic is that a catheter is usually left in situ, making it easy to top up. The disadvantages come down to difficulty of insertion and reliability.⁴ It often affects one leg more than the other, and it can be difficult to get it to spread to the side where it is required. To try and correct the spread, and to get it to an area of need, may require being rolled right onto the side for a while so that the anesthetic will move across the space.⁴

Recently, Periarticular Injection (PAI) has gained popularity as an additional tool in the multimodal approach to the management of joint arthroplasty pain. PAI has been shown to reduce surgical pain, less intravenous and parenteral opiod consumption, and provides pain control comparable to that of epidural anesthesia but without the associated complications of this modality.⁵ Periarticular infiltration with long acting liposomal bupivacaine is an effective method of controlling preoperative pain after TKA. Concentrating the PAI in the areas of the knee with increased innervation is necessary to maximize benefits from periarticular injection, and can aid in improving postoperative pain control in TKA.⁶  However, in order to achieve maximal benefit, surgeons must be familiar with the correct injection technique. Failure to comply with this technique will lead to suboptimal pain control and potentially dangerous complications.⁵

Hence, this study was compared to assess the efficiency of epidural injection and periarticular cocktail infiltration in total knee replacement patients in early operative rehabilitation period.

2.1 SOURCE OF DATA The study was conducted on patients who have undergone Primary total knee replacement in Department of Orthopaedics, kempegowda institute of medical sciences and research centre, Bangalore 2.2 INCLUSION CRITERIA  Age group 40 to 85 years  Patients with Primary osteoarthritis  Patients with secondary osteoarthritis  Patients undergoing primary TKR 2.3 EXCLUSION CRITERIA  Patients undergoing revision TKR  Patient having drug allergic reaction  Coagulopathy disorders  Severe cardiac ailments  Severe spinal deformities  Respiratory distress 2.4 PRE OP EVALUATION Inpatients meeting the inclusion and exclusion criteria are selected for the study. All the patients were explained about the aims of the study, the methods involved and an informed written consent was obtained before being included in the study. The patients were randomly divided into 2 groups of 20 patients each. 2.5 OPERATIVE PROCEDURE AND POST OPERATIVE PERIOD All patients after thorough pre-op evaluation were taken up for surgery under spinal anesthesia with standard surgical technique. Anterior midline incision, median parapatellar retinacular Approach, component cemented using either posterior cruciate substituting design without patellar resurfacing. GROUP 1: Periarticular infiltration. COCKTAIL PREPARATION: Bupivacaine 0.5% 2mg/kg, morphine sulphate(8mg) 0.8cc,adrenaline1/1000 0.3cc,antibiotic 750mg,steriods 40mg and normal saline 22cc PROCEDURE: Before components implantation, infiltrated in deep tissue which includes collateral ligaments, post capsule, quadriceps tendon, patellar tendon, fat pad, periosteum and synovial lining. GROUP 2: Epidural infiltration: Epidural catheter no. 18 passed under aseptic precautions, in lateral position after proper ascertaining of epidural space with loss of resistance technique. Bupivacaine 0.125%, 5 ml/hr by infusion was administered epidurally during intraoperative period and with the help of infusion pump post operatively In all patients knee was immobilised in a Jones compressive bandage and a knee immobiliser immediately post op. The patients were started on IV antibiotics and DVT prophylaxis. Patient were advised to continue static quadriceps exercises, Knee flexion and extension exercises, To walk full weight bearing within the limits of pain with the knee immobiliser in place. 2.6 FOLLOW UP The patient will be assessed for first 72 hours after post operatively 1. To assess the pain control and Pain relief post-operatively using VAS score 2. To assess the improvement in quadriceps function – capacity to perform a straight leg raise and knee extension 3. To assess functional outcome-knee range of function

Table 1: Age, Gender and side distribution of patients undergoing early rehabilitation post knee replacement using either periarticular cocktail injection or epidural infiltration using bupivacaine

* Chi-square test

Table 2: Comparison on post-operative day-1 between two study groups

*Mann-Whitney U test

Table 3: Comparison on post-operative day-2 between two study groups

*Mann-Whitney U test

Table 4: Comparison on post-operative day-3 between two study groups

*Mann-Whitney U test

Table 5: Comparison of result on post-operative day three between study groups

*Chi-squared test

4. 
   ILLUSTRATION:

PERIARTICULAR INJECTION:

RADIOLOGICAL ILLUSTRATION:

Pre op x ray                                                      Immediate post op x ray

Total knee replacements (TKRs) are known to be very successful procedures they are often associated with lengthy and painful recoveries. Great strides have been made in the last several years in minimizing patient discomfort and enhancing their recovery. Less invasive surgical approaches, more selective soft tissue balancing, improved patient education, and perhaps instrument and implant design have all contributed to an overall easier recovery for a patient undergoing TKR. However, improvements in pain control deserve the greatest credit for the more rapid recoveries that are now being seen.7 Post-operative pain control after TKR offers a clinical challenge. Pain contributes to immobility related complications, prolonged hospital stay and interferes with optimal post-operative knee rehabilitation. Arthrofibrosis and diminished range of movements are closely related to degree of post-operative pain.8 Hence, pain control after total knee arthroplasty (TKA) is of prime importance in the immediate postoperative period for early rehabilitation. Numerous different methods of postoperative analgesia are available, but each has its own risk of adverse side effects. Epidural/spinal anesthesia provides excellent analgesia but can be associated with postoperative headaches, intraoperative hypotension, risk of spinal infection, and delayed use of deep venous thrombosis (DVT) prophylaxis medications. Regional anesthesia carries the risk of injury to the neurovascular structures, infection, and hematoma formation. Narcotics routinely administered for pain control may cause nausea, vomiting, somnolence, respiratory depression, decreased gut motility, and urinary retention.9 In this study we have compared between two analgesic technique (peri-articular infiltration and epidural infiltration) in terms of the analgesic effect (using VAS score), early motor activities after total knee arthroplasty. Periarticular injection with long acting liposomal bupivacaine is an effective method of controlling postoperative pain after TKA while decreasing the amount of opioid consumption and its related side-effects. It has the potential benefit of increased muscle control with rehabilitation, while eliminating complications associated with opiates and peripheral nerve blockade. Careful attention to the infiltration method is necessary to prevent leaching from the soft tissues, and care should be taken to avoid intravascular injection. Concentrating the periarticular injection in the areas of the knee with increased innervation is necessary to maximize benefits from periarticular injection, and can aid in improving postoperative pain control in TKA.10 In the present study, out of 40 study subjects, 50.0% were in Periarticular cocktail injection group and another 50.0% were in Epidural infiltration group. Majority of the study subjects in both the groups i.e., 80% and 65% respectively were in the age group of 60 years and above. There was no significant difference in the age group between the two groups (P>0.05) which is similar to the findings of Hanjagi MYet al., who noted that there was no significant difference in the mean age group between the Local Infiltration Analgesia (LIA) group and Epidural Analgesia (EA) group. (P>0.05).11 Similarly another study by YaDeau JT et al., also noted no significant difference in the mean age group beween Local Infiltration Analgesia and patient-controlled epidural analgesia (PCEA) plus femoral nerve block.12 Majority of the study subjects were females i.e., 55.0% and 65.0% in Periarticular cocktail injection and Epidural infiltration group respectively and there was no significant difference in the distribution of gender between the two groups (P>0.05) which is similar to the findings of Hanjagi MYet al., where majority of the study subjects were females and there was no significant difference in the distribution of gender between the groups.11 In the Periarticular cocktail injection group, majority ie., 65.0% had left knee joint involvement whereas in Epidural infiltration group, majority ie., 55.0% had right knee joint involvement and there was no significant difference in the side of knee joint involvement between the two groups (P>0.05) whereas according to Hanjagi MY et al there was no significant difference between the groups in terms of side of operation.11 In the present study, there was no significant difference in the median of standing VAS scores on post-operative day one and three (P>0.05) whereas a significant difference in the median of standing VAS scores on post-operative day two (P< 0.05) between the Periarticular cocktail injection group and Epidural infiltration group which is similar to the study findings of a systematic review and meta-analysis by Yan H et al 13which included 9 RCTs. Yan H et al noted that there was no significant difference between local infiltration and epidural analgesia VAS scores at rest at 12 hours postoperatively (MD = −0.42; 95% CI = −1.03-0.20) in five studies14-18 and at 24 hours postoperatively (MD = −0.08; 95% CI = −0.49-0.33) in nine studies14-22 whereas the results combined from four studies showed that in TKA local infiltration significantly reduced the VAS score at 48 and 72 hours.15,17,19,20 Median of walking VAS scores of Periarticular cocktail injection group on post-operative day one, two and three were slightly lower than Epidural infiltration group but this difference was statistically significant (P<0.05) only on day two and day three and on day one the difference was not significant (P>0.05) as per the current study. Yan H et al in his systematic review and meta-analysis noted that there was no significant difference in the VAS scores on movement between local infiltration and epidural analgesia at 24 hours (MD = 0.38; 95% CI = −0.37-1.12) whereas at 48 hours postoperatively local infiltration had lowered VAS score on movement at (MD = −1.08; 95% CI = −1.86 to −0.29).13 In the present study, degree of movement on post-operative day one, two and three were slightly more ie.,70 degrees (60-75), 90 degrees (80-90) and 100 degrees (90-110) respectively in the Periarticular cocktail injection group compared to 65 degrees (50-70), 80 degrees (70-90) and 90 degrees (80-100) in Epidural infiltration group respectively and the difference was not statistically significant (P>0.05) whereas according to the Tsukada S et al., in the periarticular injection group, the mean knee flexion angle was small but significantly better at postoperative day 1 (64.2° versus 54.6°; p = 0.0072) and postoperative day 2 (70.3° versus 64.6°; p = 0.021) than in the epidural analgesia group.17 In the present study, degree of straight leg raise on post-operative day one, two and three were 50 degrees (40-60), 65 degrees(55-70) and 60 degrees(70-80) respectively in the Periarticular cocktail injection group which was almost equal compared to 50 degrees (40-60), 60 degrees (50-75) and 60 degrees (70-80) in Epidural infiltration group respectively and the difference was not statistically significant (P>0.05). In a study by Chaumeron A et al., who studied, capacity to perform a straight leg raise between periarticular anesthetic infiltration (PAI) and femoral nerve block noted that on days 1 to 3, subjects in the PAI group experienced better capacity to perform the straight leg raise.23 According to Davies AF et al., who compared epidural infusion or combined femoral and sciatic nerve blocks as perioperative analgesia for knee arthroplasty found no significant difference in degree of straight leg raise between the groups.24 In the current study, there was no statistically significant difference in the post-operative outcome between the Periarticular cocktail injection group and Epidural infiltration group and hence both the groups were comparable indicating Periarticular cocktail injection to be noway inferior compared to Epidural infiltration whereas Hanjagi M Y et al., similarly has found local infiltration analgesia provides simple, safe comparable analgesic efficacy and earlier ambulation than epidural analgesia post-operatively after total knee replacement surgery.8 Tsukada S et al., has also noted that Periarticular injection was associated with better outcome in terms of pain relief during the first twenty-four hours following simultaneous bilateral total knee arthroplasty compared with epidural analgesia. Periarticular injection may be preferable to epidural analgesia for pain relief after simultaneous bilateral total knee arthroplasty.15 LIMITATIONS: In this study, we focused on the pain score, degree of movement shortly after TKA; longer follow-up would be preferable to evaluate the results, especially in terms of long-term knee motion and complications. A study about the long-term outcome of peri-articular infiltration is needed to confirm the advantage of local infiltration. Sampling procedure being purposive, the selection of representative sample and generalizability becomes a limitation. Hence, the study needs to be conducted in a larger sample and in a community based setting to generalize the obtained results.

• The pain control and relief in peri-articular cocktail injection group was slightly better compared to epidural infiltration group post-operatively.
• The improvement in peri-articular cocktail injection group quadriceps function – capacities to perform a straight leg raise and knee extension was as good as epidural infiltration post-operatively
• The overall functional outcomes in peri-articular cocktail injection group were comparable to the epidural infiltration group.
• Though both peri articular cocktail injection and epidural infiltration outcomes are comparable, we can achieve excellent analgesia in peri articular cocktail injection on first and second day without side effects of epidural infiltration like hypotension, vomiting, constipation  ,sleep apnea , institution of low molecular heparin and provision of pump

DECLARATIONS:

Funding: None

Conflict of interest: None declared

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