Total Hip Replacement

Transcription

1 Total Hip Replacement FRANK E. STINCHFIELD,* M.D., ERIc S. WmTE,** M.D. From the New York Orthopaedic Hospital, Columbia-Presbyterian Medical Center, New York City OUR clinical experience with total hip replacement is based upon the work of Charnley.2' 6 In 1958, he departed from the anatomic approach to arthroplasty of the hip and designed a mechanical hip joint based upon biomechanical and engineering principles. The essential features of the low friction arthroplasty are: (1) A metal-to-plastic rather than metal-to-metal joint surface is used with a small diameter femoral head. The surface friction between metal and plastic is considerably less than metal-tometal and the small diameter head reduces the contact area between the articulating surfaces.3 (2) At the time of operation, the acetabulum is deepened in order to medially displace the center of rotation and the weight-bearing axis. This reduces the moment of force on the prosthetic components. In addition, the hip abductor muscles are transplanted laterally and distally to allow them to work at a more effective lever arm. (3) A self-curing cement, methylmethacrylate, is used to bond both the acetabular and femoral components to endosteal bone. Methymethacrylate has no adhesive properties, but acts as a filler or mechanical bond which allows a more uni- -'orm distribution of stress over a large surface area. These three features are designed to minimize wear and to prevent loosening of the prosthesis (Fig. 1). *161 Fort Washington Avenue, New York, New York * *622 West 168th Street, New York, New York Presented at the Annual Meeting of the American Surgical Association, March 24-26, 1971, Boca Raton, Florida. 655 Methylmethacrylate The unanswered question about the use of cement, which has led to conservatism in the United States, is the long-term tissue tolerance of this material in the human body. Charnley's monograph, Acrylic Cement in Orthopaedic Surgery, discusses this question in depth.4 Laboratory investigation has shown that the initial host response to methylmethacrylate in bone is a narrow margin of cell death, presumably caused by the heat of polymerization followed by a fibroblastic response with interspersed giant cells. After the passage of time, normal remodeling and bone marrow function take place adjacent to cement separated only by a thin layer of fibrous tissue."'5' 21 At The New York Orthopaedic Hospital, we have done in vivo studies utilizing the canine femur to try and separate the various factors which elicit the histological changes toward methylmethacrylate.13 Under conditions of a minimum shearing-load, histologic sections 6 months after implant show normal bone function directly adjacent, to cement with no residual fibrous lining. Further studies are being performed to study the relationship between increased shearing-loads, i.e., motion, and the amount of fibrous tissue lining between bone and cement. Operative Technic A short description of the operative technic would seem indicated. A lateral approach to the hip joint is used. Osteotomy of the greater trochanter is recommended to minimize muscle dissection to allow easier dislocation and to facilitate adequate acetabular exposure. This also permits lat-

2 656 STINCHFIELD AND WHITE FIG. 1. Low Friction Arthroplasty of Charnley. Barium sulfate is added to the cement to make it radiopaque. A wire outlines the outer surface of the plastic socket. Fixation holes are drilled into the acetabulum to produce maximum stability at the cement-bone interface. eral and distal displacement of the abductor muscle. A straight 8 to 10 inch incision is centered over or just posterior to the greater trochanter and extends along the femoral shaft towards the iliac crest. The fascia lata is incised and the tensor fascia femoris muscle is retracted anteriorly. The junction between the origin of the vastus lateralis and the insertion of the gluteus minimus and medius is identified. The fatty tissue and investing fibers of the vastus lateralis are then reflected from the joint capsule. The anterior capsule is incised in the direction of the femoral neck and a largs cholecystectomy clamp is introduced intracapsularly, superior to the femoral neck and just medial to the greater trochanter (Fig. 2). This allows placement of a Gigli saw which is used to osteotomized the greater tro- Ann. Surg. * Oct chanter. A limited capsular excision is usually necessary to allow anterior dislocation of the femoral head which is accomplished by flexion, adduction, and external rotation of the patient's leg. The Gigli saw is used again to resect the femoral head at the mid-neck level. Self-retaining retractors are used to expose the acetabulum which is deepened and widened with special reamers (Fig. 3). The high density polyethylene acetabular socket is cemented in the deepened acetabulum at a 45-degree angle from the horizontal and in neutral rotation. After the cement holding the acetabular component has hardened, attention is directed toward the femoral shaft. The medullary canal is then reamed for reception of the metal prosthesis. A trial prosthesis is introduced into the prepared shaft. The hip joint is relocated and a range of motion is carried out. Any osteophytes that impinge upon the prosthesis or restrict hip motion are removed. After placing horizontal and vertical trochanteric fixation wires, the permanent prosthesis is cemented in place. The hip is relocated a second time and the greater trochanter is secured in its new position with the two #18 gauge wires. FIG. A cholecystectomy clamp is used to route the Gigli saw intracapsularly, medial to the hip abductors prior to osteotomy of the greater trochanter.

3 Ann. Surg. Oct Vol. 174 * No. 4 Patient Selection Newness of the operative technic and the use of methylmethacrylate cement prompted us to restrict our indications for total hip replacement.9 Sixty years of age is the approximate lower limit for patients with unilateral hip disease. A slightly lower age limit is allowed for those patients with bilateral hip disease since disability is so much greater when both hips are involved. Many of the candidates for low friction arthroplasty have had previous attempts at conventional arthroplasty which have failed. The ideal candidate for the procedure is one in whom the only alternative is a Girdlestone resection. In all of the above situations pain is the primary indication for surgical treatment while limited range of motion and gait disturbance are only secondary considerations. An absolute contraindication to the procedure is a history of infection in the ipsilateral hip joint. Patients who have had multiple hip surgery in the past must undergo careful tests to rule out late, lowgrade infection. The surgeon must be prepared to abandon the procedure if during the operation a positive bacterial smear is obtained from the operative wound, or if suspicious granulation tissue is present. Relative contraindi@ations are patients having little disability or who are still able to work when their pain is relieved by analgesics. Table 1 lists the frequency of various hip disorders referred to our institution which warranted total hip replacement. Hip Assessment A prospective study has been established on all patients for low friction arthroplasty (LFA) at The New York Orthopaedic Hospital. The numerical grading system of D'Aubigne and Postel has been adopted to measure the degree of pain, function, and mobility in each hip.8 Grade 1 denotes the most severe condition while Grade 6 indicates the normal. Each patient is then placed in one of three groups TOTAL HIP REPLACEMENT 657 FIG. 3. The acetabulum is exposed laterally. After deepening it with reamers, fixation holes are drilled in the acetabulum to increase the contract area of cement and bone. according to the type of involvement. Group A indicates unilateral hip disease; Group B bilateral hip disease and Group C includes patients with either unilateral or bilateral hip disease who have some additional medical or orthopaedic condition which restricts function. Results of Surgery The first one hundred low friction arthroplasties were performed at The New York Orthopaedic Hospital between April 1969 and May This study group consisted of 93 patients, seven of whom had bilateral arthroplasties. Two died from unrelated causes before their follow-up visit. Eightyfour patients actually returned for examination. The shortest interval between surgery and the time of hip assessment was six months and the longest period was eighteen months. The average follow-up time was ten months. The actual time elapsed between surgery and the reading of this paper ranged from ten to twentythree months. This additional follow-up time is important when considering the incidence of posssible late wound infection. Pain. Every patient interviewed had significant and many times dramatic relief of pain. Table 2 shows that all but seven patients were graded 5 and 6, postoperatively.

4 658 STINCHFIELD AND WHITE Ann. Surg. * Oct Vol. 174 * No. 4 FIG. 4A. J. B., is a 56-year-old man with osteoarthritis secondary to congenitally subluxated hips. Five years ago he underwent bilateral osteotomies but did not obtain permanent relief from pain. At the time of evaluation for LFA, he had Grade 3 pain and was unable to work. FIG. 4B. The failed osteotomies were converted to low friction arthroplasties. At oneyear followup, he has returned to work as a traveling salesman and walks with no pain and no aids. Mobility. Table 3. The majority of patients had a striking increase in range of motion. A few patients having had multiple procedures and who formed heterotopic bone, did not have any increase in range of motion. No one, however, had less than his preoperative range of motion. Function. Table 4. Our analysis of function has been divided into the three previously mentioned categories, A, B, and C. It should be emphasized that function relates to gait pattern and overall activity. The patients in Group A did uniformly well. Those in Group B did not fare quite as well. Our interpretation of this finding is that many of the Group B patients are limited by arthritic involvement of their opposite hip. When those patients with symptomatic disease in the opposite hip come to surgery, the results in Group B should approach that of Group A. Improvement in Group C after surgery was quite variable. We believe that this reflects the degree of limitations imposed by systemic medical or orthopaedic conditions rather than hip function, per se. Complications Tables 5 and 6. The data on our complications have been updated to include -our first 200 procedures. Although the most

5 Ann. Surg. * Oct frequent postoperative complication was urinary retention requiring a Foley catheter, two more important problems warrant discussion. Thromboembolism. Because of the danger of deep wound hematoma and the risk of subsequent wound infection,7 we have been selectively rather than routinely, anticoagulating our patients with coumadin. After analyzing the results of our first 100 procedures, the incidence of thromboembolic complications was alarmingly high, 15 per cent. This prompted us to take very stringent measures during the postoperative period to prevent thrombophlebitis. In addition, we have instituted a controlled study to evaluate the use of Dextran-40 as a prophylactic anticoagulant. Although recent reports in the surgical literature have appeared favoring the use of Dextran," 10 our preliminary results based upon 60 treated and 60 controlled patients show just as many pulmonary emboli and episodes of thrombophlebitis in the treated groups as the control group.14 Further studies are now being carried out in respect to the use of Dextran 70. Infection. The most important and dangerous complication of LFA is postoperative deep wound infection. Fortunately, we have had little experience in this regard. Although we have had three superficial wound hematomas which drained and grew out an organism, there have been no early and no late deep wound infections. Charmley's wound infection rate in a large series of patients was unacceptable prior to the institution of stringent measures to prevent intraoperative contamination. These included the use of sterile laminar air flow system and the complete isolation of the surgeons' flora from the operative field.5 We currently do not have a laminar air flow operating room for implant surgery. Nevertheless, every effort is made to carry out the strictest aseptic technic in order to eliminate any potential source of intraoperative wound inoculation. Another factor to be considered in the TOTAL HIP REPLACEMENT TABLE 1. Diagnostic Categories Primary osteoarthritis 120 Failed previous surgery 36 Secondary osteoarthritis 16 Rheumatoid arthritis 15 Avascular necrosis postfracture 7 Mixed arthritis 6 TABLE 2. Pre- and Postoperative Pain (90 Hips) 659 Grade Preop Postop TABLE 3. Pre- and Postoperative Mobility (90 Hips) Grade Preop Postop TABLE 4. Pre- and Postoperative Function (84 Patients) Grade A Preop Postop B Preop Postop C Preop Postop TABLE 5. General Complications (200 Hips) Urinary retention 83 Urinary tract infection 36 Pulmonary embolus 15 Atelectasis 6 Paralytic ileus 5 Gastrointestinal bleed 3 TABLE 6. Local Complications (200 flips) Thrombophlebitis 12 Deep wound hematoma 10 Peroneal palsy (transient) 4 Subluxation 2 Dislocation 1 Deep wound infection 0

6 660 STINCHFIELD AND WHITE Ann. 8urg. * Oct FIG. 5A. L. J., is a 70 year-old woman with a congenital dislocation of her left hip. In recent years, her hip had become painful and limited her activity. prevention of wound infection is the use of prophylactic antibiotics. Our department published a paper in January 1970 advocating the use of prophylactic antibiotics in major hip and back surgery." This was recommended on the basis of a controlled comparison of postoperative wound infections utilizing Penicillin-G as the prophylactic antibiotic choice. Whenever selecting a prophylactic antibiotic, one must be familiar with his own hospital's infecting organisms and their sensitivities. All of the patients undergoing LFA received Penicillin-G or an alternate antibiotic before, during, and after operation. Technical Complications. Technical complications of LFA also can lead to a poor result. Most patients undergoing LFA as their initial surgical treatment for primary osteoarthritis present no difficulty for those properly trained in the technic. However, revision surgery for a previously failed arthroplasty is considerably more difficult. Dislocation of the hip joint, resection of heterotopic bone, preparation of the acetabulum and aligment of the prosthesis are all technical barriers with which one must contend. The following two examples illustrate difficulties imposed by a deficient acetabulum. The first patient (Fig. 4) represents failed bilateral osteotomies which previously had been performed for congenitally subluxated hips. Although hardware removal, dislocation, and acetabular preparation were difficult, a good end result was achieved. The second example (Fig. 5) is that of an elderly lady with a congenital Fic. 5B. An LFA was performed but the acetabular component was not well seated because of an inadequate bony roof.

7 Ann. Surg. Oct TOTAL HIP REPLACEMENT 661 r_r FiG,. 5G. Two months after operation, fixation of the acetabular socket was lost and the prosthesis dislocated. dislocation. No acetabulum is present. Attempts to create an acetabulum failed because of lack of bony support over the acetabular socket. Two months after operation and after a limited amount of weightbearing, this prosthesis loosened and dislocated. The entire prosthesis, including cement, had to be removed. The patient was in no way helped by her original operation. Summary The early results of our low friction arthroplasty series are very encouraging. We believe that total hip replacement is here to stay, but we know that this procedure carries with it the potential of many and major complications. Inherent in this method of low friction arthroplasty is the possibility of catastrophic results unless the principles laid down are carefully followed. We believe that thoughtful selection of patients and strict attention to operative FIG. 5D. The entire prosthesis had to be removed leaving the patient with her preoperative deformity, after two major surgical procedures. asepsis are the two most important factors in this procedure. Acknowledgment The authors wish to acknowledge the contribution of Nasseroddin S. Eftekhar, M. D. and Kenneth M. Kurokawa, M. D., in the initiation and continuation of this prospective study. References 1. Atik, M., Harkness, J. W. and Wichman, H. W.: Prevention Fatal Pulmonary Embolism. Surg. Gynec. Obstet., 130:403, Charnley, J.: Arthroplasty of the Hip. A New Operation. Lancet. 1:1129, Charnley, J., Kamangar, A. and Longfield, M. D.: The Optimum Size of Prosthetic Heads in Relation to the Wear of Plastic Sockets in Total Replacement of the Hip. Med. Biol. Engin., 7:31, Charnley, J.: Acrylic Cement in Orthopaedic Surgery. Balitmore, Maryland, Williams and Wllins Co., Charnley, J. and Eftekhar, N. S.: Postoperative Infection in Total Prosthetic Replacement Arthroplasty of the Hip Joint. Brit. J. Surg., 56:641, Charnley, J.: Total Hip Replacement by Low Friction Arthroplasty. Clin. Orthop., 72:7, 1970.

8 662 STINCHFIELD AND WHITE Ann. Surg. Oct Crawford, W. J., Hillman, F. and Charnley, J.: A Clinical Trial of Prophylactic Anticoagulant Therapy in Elective Hip Surgery, Center for Hip Surgery, Wrightington. Hospital Internal Publication, No. 14, May D'Aubigne, R. M. and Postel, M.: Functional Results of Hip Arthroplasty with Acrylic Prosthesis. J. Bone Joint Surg., 36A:451, Eftekhar, N. S.: Low Friction Arthroplasty: Indications, Contraindications, and Complications. Presented at The Section on Orthopaedic Surgery, 119 Annual Meeting, American Medical Association, Chicago, Illinois, June Evarts, C. M. and Feil, E. I.: Thromboembolism after Elective Surgery of the Hip. Orthop. Clin. N. Amer., 2:167, Fogelberg, E. V., Zitzmann, E. K. and Stinchfield, F. E.: Prophylactic Penicillin in Orthopaedic Surgery. J. Bone Joint Surg., 52A:95, Henrichsen, E., Jansen, K. and Krough-Poulson, W.: Experimental Investigation of the Tissue Reaction to Acrylic Plastics. Acta Orthop. Scand., 22:141, Kurokawa, K. M. and Pawluk, R.: Response of Canine Bone to Self-Curing Methylmethacrylate. In preparation. 14. Rothermel, J. E.: Personal communication. 15. Wiltse, L. L., Hall, R. H. and Stenejem, J. C.: Experimental Studies Regarding the Possible Use of Self-Curing Cement in Orthopaedic Surgery. J. Bone Joint Surg., 39A:961, DIscusSION PRESIDENT-ELECr MooRE: I would like to ask Dr. Stinchfield a couple of questions. What about Paget's disease? Is that a contraindication? How do you choose this, versus a cup or a prosthesis, or do you pretty much just go over this? Finally, our group, has been concerned over this late sepsis, and we wonder if the plastic sets up a reaction in the acetabulum which favors later localization of organisms from the bloodstream. In other words, could it be blood-borne to the site, rather than true, surgical infection? DR. KENNETH W. WARREN (Boston). Charnley gives considerable credit to the "greenhouse" in reducing the incidence of infection in total hip replacement. Do you feel that the "greenhouse" or some form of laminar air flow is a significant factor in controlling infection in this procedure? Do you use local antibiotic spray or irrigation during the operation? DR. EDWIN W. SALZMAN (Boston): We have recently completed a study of 169 patients with Vitallium mold arthroplasty, in whom we compared the efficacy of agents affecting platelet function with warfarin for the prophylaxis of venous thromboembolism. In that study dextran and aspirin were each as effective as warfarin, which was significantly more effective than the control. In a companion study of total hip arthroplasty which is still in progress, the incidence of thromboembolism appears higher than following the cups; perhaps Dr. Stinchfield would comment on this difference. The preliminary results of this second study appear to show that dextran is not as effective as warfarin in these high risk patients. DR. FRANK E. STINCHFDELD (Closing): We have operated upon five patients with Paget's Disease. However, this type of patient is not the ideal one on whom to operate-if one expects to obtain an excellent result. Paget's, per se, produces pain and one cannot eliminate the disease by doing a total hip replacement. In the five patients operated upon, two results were disappointing and three patients said they received relief from pain -but still had their Paget's pain. The question was asked-"when do you use cups?" I want to say that I still consider the mold operation to be an excellent one and continue to use it on patients in the younger age group-those between the ages of 20 to 55 years. Also, we use the cup arthroplasty in those patients where there has been previous infection. One should never attempt a total hip replacement where there has been prior infection. Late sepsis is something that I cannot comment on because we have been doing this procedure for but the past 2 years. We may experience this complication in another 1 to 3 years but to date we have had none. I think that when infection occurs it probably is introduced at the time of operation and is not blood borne. Actually, there is considerable evidence to prove that methylmethacrylate does not really give very much soft tissue reaction. The question by Dr. Warren relative to the 'greenhouse,' the laminar air flow, and the space suit, is very appropriate- as all of these contribute to discipline. There is no doubt of that. However, in our series, we have not found the 'greenhouse' to be essential. Relative to the use of antibiotics we have reported our findings in a previous study. In that study we reported on 236 patients who had had mold arthroplasties. The infection rate was reduced from 5.4 to 1.2 by the use of appropriate prophylactic antibiotics. Regarding the use of anticoagulants, I agree that anticoagulation is helpful. We anticoagulate all of our patients who have had a mold arthroplasty, in an effort to prevent thrombophlebitis. However, in the total hip replacement patient, we fear hematoma more than thromboembolism. Anticoagulation may cause bleeding and hematoma more than thromboembolism. Anticoagulation may cause bleeding and hematoma-which could lead to infection. Therefore, we do not routinely anticoagulate the total hip patient.