Address for Correspondence:

Dr.P.Gopinathan, MS(Ortho);DNB;MNAMS
Asst.Professor of Orthopaedics
Medical College, Calicut 673008
Kerala,India
E-Mail: drpgopinath@yahoo.com

ABSTRACT
Background:
Total Knee Replacement (TKR) is one of the greatest invention of the last century. The surgical technique is simple and easily reproducible with consistent results. But infection remains a significant issue even in the best set up. The objective of the study was to analyse the result of TKR done without the use of surgical diathermy - with reference to the rate of infection and wound healing. 
Patients and Methods:
We analysed the result of 22 consecutive primary total knee replacement surgeries regarding wound healing and incidence of infection. Duration of the study was from June 1999 to August 2003. All case of primary TKR done in the Department of Orthopaedics, Medical College, Calicut during the above mentioned period were selected. Analysis were adjusted to the age, sex, diagnosis, co-morbid conditions and previous surgical interventions. Pneumatic tourniquet were routinely used. Surgical diathermy was never used.
Observation and Results:
Twenty two case of TKR in 20 patients were selected for the study. Two cases were bilateral. Six patients had diabetes mellitus, which was controlled at the time of admission. Four patient had IHD, 12 cases had lateral instabilityand 10 cases had medial instability. Semi constrained PCL sacrificing prosthesis was used in all patients. The average range of post operative flexion was 110^o.
The average follow up period was 2 years. 
Discussion:
Primary TKR is a rewarding surgery,as far as the patient satisfaction and the functional outcome are concerned. But infection remains as an unsolved misery, in any set up. The average rate of infection after primary TKR is 2% even in the best set up. Any efforts aimed at reducing or eliminating it should be given its due credit. Avoiding surgical diathermy at any stage of surgery reduces the tissue death and definitely reduces the chances of infection. In this study, we could achieve 0% infection rate with a short term follow up. The infection in any surgical procedure is multifactorial in origin. We need further studies in identical set up in future for further confirmation of this claim. 
Conclusion:
Making all the tissues around the prosthesis viable and living by not using a surgical diathermy is the best way to avert infection after TKR.
Keywords:Yotal Knee Replacement,surgical diathermy


Introduction

Total Knee Replacement (TKR) is one of the successful surgeries invented in the last century. The Procedure is simple and easily reproducible with consistent results regarding patient satisfaction and functional outcome. But infection remains as a greatest issue even in the best set up. The rate of infection ranges from 1% to 3% with an average of 2% according to international standard.
The objective of the study was to analyse the results of primary TKR done without the use of surgical diathermy regarding the rate of infection and wound healing.

Patients and Methods

We analysed the results of 22 consecutive primary total knee replacement surgeries regarding infection rate and wound healing. The study was done at the Department of Orthopaedics, Medical College, Calicut from June 1999 to August 2003. Analysis was adjusted to the age, sex, diagnosis, co-morbid conditions and previous surgical interventions. Of the 22 cases, in 20 patients 15 were females and 5 were males - 2 cases were bilateral. 12 cases were on the right side and 6 cases were on the left side. All cases were operated using anterior midline parapatellar approach. All were done with pneumatic tourniquet. The average time from skin incision to skin closure was 2 hours and 10 minutes. Surgical diathermy was not used in any patients. Haemostasis during surgery was achieved using pneumatic tourniquet. Post operative compression bandage along with suction drain was applied routinely. There were no cases of delayed wound healing or wound infection. Imported prosthesis were used in 12 cases,while 10 cases were operated with Indian prosthesis. Patella was preserved in all cases. All prosthesis were semi constrained. Routine pre operative and post operative antibiotics were given. Fixed bearing prosthesis was done in all cases. The prosthesis was fixed using bone cement. Intramedullary alignment guide was used in all cases on the femoral side and external alignment guide in the tibial segments. Ligament reconstruction was not done in any case. In severe ligamentous laxity, we opted for a bigger polyethylene. All patients were pre operatively assessed using a standing 3-joint AP and lateral view X-rays. Lateral release was done routinely in imported prosthesis. Lateral release was done in Indian prosthesis only in valgus deformity. Patellar tracking was assessed preoperatively with a skyline view. Three-degree external rotation was given on the femoral segment in Indian prosthesis, but not in imported prosthesis (FST3). 

Observations and Results

Twenty-two cases in twenty patients operated were followed up for an average period of two years. There were 15 females and 5 males. Two cases were bilateral, 12 cases were on the right side and 6 cases were on the left side. 12 cases had varus deformities with lateral instability. 10 cases had severe valgus deformity with medial instability. 6 patients had diabetes mellitus, but were controlled at the time of admission. 4 patients had ischaemic heart disease (not recent). Fixed flexion deformity of 10-20^o was present in 6 cases and fixed flexion deformity of 20-35^o was present in 16 cases. Varicosity of the limb was present in 4 cases. 2 cases had dynamic recurvatum deformity. Preoperative range of motion was free flexion of 20-50^o in 6 cases, 30-60^o in 14 cases. Two cases had range of flexion from 0-70^o. Post operatively, Indian prosthesis had range of motion from 0-90^o, imported prosthesis had free flexion from 0-120⁰ in 10 cases, 2 cases had 0-130^o flexion. Routine lateral release was done in all patients with imported prosthesis. In Indian prosthesis, lateral release was done in 4 cases of valgus deformity only. 3^o external rotation was given on the femoral segment in all Indian patients but not in imported prothesis (FST3). Tibia was cut perpendicular to the anatomical axis in all cases. PCL was sacrificed in all cases.

Post operative X-rays were taken on the second day , at 4 weeks and there after at 3 month intervals to look for any instability or osteolysis at the cement bone junction, which could be an early evidence of subacute infection. But there was no case of bone cement junction osteolysis in the study. Suture removal was done on the 12th post operative day. There was no case of delayed wound healing or wound infection. Non weight bearing mobilization was done on the 3rd post operative day. Partial weight bearing with a pair of crutches was started on the 7th day. Full weight bearing was started on 14th day. In bilateral cases, unprotected weight bearing started on 24th day after surgery. Bilateral cases were done in 2 sittings,the second sitting  7 days after the first one.


Discussion:

Primary TKR is a rewarding surgery as far as the patient satisfaction and functional outcome are concerned, but infection remains as an unsolved problem if it sets in. The rate of infection ranges from 1-4% even in the best set up with an average infection of 2%. Any efforts at reducing the rate of infection and eliminating it should be given its due importance. Surgical diathermy either used for cutting the tissues or for coagulating the bleeding points kills the tissues and produces a cooked meat media around the prosthesis. Cooked meat media gives a viable atmosphere for the bacteria to set in and multiply and such a situation leads on to establish infection. The aim of not using surgical diathermy is avoiding a cooked meat media around the prosthesis so that only a viable tissue around the prosthesis with vascular supply remains. In old patients the vascularity the around the knee is always compromised either due to arterio sclerosis or atherosclerosis. In highly vascular areas, the colonization of the wound by bacteria may not lead on to infection. The bacteria are taken care of by the macrophages in the circulation. In areas, which are not very vascular, the colonized bacteria settle for an established infection. 

No surgical procedure should create a viable atmosphere around the prosthesis for the colonized bacteria to settle there for infection and so dead tissue around the prosthesis should be avoided at any cost. In the study there were no cases of infection or delayed wound healing. We attribute 0% infection rate to the technique of non cauterized total knee replacement, ie not using surgical diathermy at any stage of surgery. The absence of infection may also be due to the short term nature of the study or because of the use of a relatively less constrained prosthesis. The infection rate is common in more constrained prosthesis. Infection in any surgical procedure is multifactorial in origin. The surgeon should take all the precautions to reduce the rate of infection at different levels. In this study we did not do a comparison with and without surgical diathermy. We need further studies in future regarding the use of diathermy in a setting like Knee Replacement surgery. The lack of infection in our setting calls for further studies and encourages avoidance of surgical diathermy in Knee Replacement Surgery.


Conclusion:

Infection plays the single most unsolved misery in total knee replacement. The technique of non cauterized TKR has reduced the infection rate to 0%. The use of surgical diathermy improves the surgeon's convenience during surgery, but is definitely harmful for the patient. Pneumatic tourniquet with a bloodless field helps the surgeon to finish the surgery fast. By not using surgical diathermy, only viable and living tissue covers the prosthesis which does not produce a fertile media for the bacteria to multiply. The future total knee replacement surgery may be by using the technique of non cauterized TKR. Since infection is multifactorial in origin, we need further studies in this settings, but initial results are definitely encouraging.


References:

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