The Ranawat Award. Comparison of surgical approaches in total knee arthroplasty

A series of 123 revision total knee replacements performed at three centers and followed up for 2 to 4 years was evaluated. In cases in which exposure could be obtained with undue tension on the patellar tendon, the surgical approach was modified using either quadriceps turndown (14 cases) or tibial tubercle osteotomy (15 cases). The remaining 94 patients underwent a standard operative approach that consisted of a medial parapatellar capsular incision which in 31 cases was combined with a quadriceps snip. The results were compared using the Knee Society clinical score, a patient satisfaction survey, and a patellofemoral questionnaire. Postoperatively, the group of patients who had a quadriceps snip was equivalent to the group of patients who underwent a standard approach in every parameter measured, and the groups therefore were combined for comparison purposes. The patients who had quadriceps turndown and the tibial tubercle osteotomy had equivalent scores postoperatively both of which were significantly lower than the standard group. The group of patients who had quadriceps turndown had a significantly greater increase in arc of motion than the tibial tubercle osteotomy group. The tibial tubercle osteotomy group had a lower degree of extension lag but a higher percentage of patients who had difficulty with kneeling and stooping and a higher percentage of patients who had difficulty with kneeling and stooping and a higher percentage of patients who thought the surgery was unsuccessful in relieving pain and unsuccessful in returning them to normal daily activities.     

The John Charnley Award. Prophylaxis of fat and bone marrow embolism in cemented total hip arthroplasty

The efficiency of a new cementing technique developed to prevent the risk of intraoperative pulmonary embolism was assessed. Seventy patients with coxarthrosis entered into a prospective, randomized clinical trial. In the control group of 35 cases the total hip replacement was cemented conventionally. In the second group a proximal drainage placed along the Linea aspera, and a distal drainage placed in the diaphysis, created a vacuum in the medullary cavity of the femur during the insertion of the stem. The operation was performed with the patient under blood gas analysis and hemodynamic and transesophageal echocardiography monitoring. Severe transatrial embolic events were observed during the insertion of the femoral component in 94% of the cases of the control group and in 14% of the cases of the vacuum group; the difference is statistically significant. A significant decrease of arterial partial pressure of O2 (-40.8 mm Hg) and increase of the pulmonary shunt values (+28.3%) occurred 5 minutes after the observation of embolic events in the cases operated on conventionally, but these parameters showed minimal changes in the vacuum group. The rise of intramedullary pressure in the femur is the most decisive pathogenic factor of pulmonary embolism during total hip arthroplasty. The logical prophylactic measure to prevent intravasation of fat and bone marrow is to create sufficient drainage. The cohorted investigation showed the value of the vacuum cementing technique for a substantial reduction of intraoperative embolism and pulmonary impairment.     

The Rotaglide total knee arthroplasty. Prosthesis design and early results

The Rotaglide knee (Cozim Medical, UK) is a three-part knee containing a mobile polyethylene meniscal platform, imparting reduced loosening forces to the tibia. The femoral component design provides a high degree of congruency throughout the range of motion from 0 degree to 110 degrees, and both femoral and tibial components ensure minimal bone removal. The system is versatile, including a large number of component options, and it may be used in both primary and revision arthroplasties. The first results in 170 cemented knees (161 patients) with 2- to 5-year follow-up periods (average, 3.1 years) were very encouraging (excellent or good in 95% of knees, based on the British Orthopaedic Association knee assessment system). Poor results were seen only in revision cases. There have been no mechanical implant failures and no platform bearing dislocations, and the platforms continue to move as documented by postoperative roentgenograms, which show the metal markers of the platforms moving anteriorly in flexion and posteriorly in extension.     

Survivorship of cemented total knee arthroplasty

The survivorship method of analysis was used to compare the failure rate and overall success of 2629 cemented primary total knee arthroplasties during a 22-year period by the senior surgeon. There were 215 Total Condylar prostheses with a polyethylene tibia, 265 of the Posterior Stabilized type with an all polyethylene tibia, 2036 Posterior Stabilized with a metal backed tibial component, 49 Posterior Stabilized with modular augmented components, and 64 with the Constrained Condylar system. Failure was considered revision or planned revision. The Total Condylar series had an average annual failure rate of 0.46% and a 21-year success rate of 90.77%. The Posterior Stabilized prosthesis with an all polyethylene tibia had an average annual rate of failure of 0.38% and a 16-year success rate of 94.10%, and this prosthesis with a metal backed tibial component had an annual failure rate of 0.14% and a 14-year success rate of 98.10%. The Posterior Stabilized series with modular components had an average annual rate of failure of 0.59% and a 10-year success rate of 93.63%. The Constrained Condylar knee series had an average annual failure rate of 0.26% and a 7-year success rate of 98.12%. This review represents a retrospective analysis of consecutive series of cemented, total knee arthroplasties, whose annual failure and success rates were done during differing time spans. The overall success rate was not influenced by gender, age, diagnosis, or percentage of ideal body weight. Failure was considered revision or planned revision. The best and worse case scenarios were calculated for each series. Long term results of cemented, total knee arthroplasty with a relatively conforming articular surface has been shown to be a reliable procedure with excellent survivorship.     

Flexion space configuration in total knee arthroplasty

Equal resection of the posterior femoral condyles combined with a 90 degree tibial resection results in a trapezoidal flexion space. Two groups of patients were studied; in one group, the flexion space was allowed to remain trapezoidal, whereas in the other group, the anteroposterior femoral resections were externally rotated to allow rectangularization of the flexion space. In the second group, the range of flexion was increased and the incidence of medial tibial pain and zone I radiolucencies decreased. Other than for knees in a hypervalgus position before surgery, the mean amount of rotation required was 3 degrees +/- 0.2 degrees.     

Patellofemoral complications in symmetrical total knee arthroplasty

A review of 356 Kinemax (Howmedica, Inc, Rutherford, NJ) cemented posterior cruciate ligament-retaining condylar total knee arthroplasties employing a symmetrical femoral component articulating with a medially offset symmetrical dome patella component was carried out to examine the results and determine the incidence and nature of the patellofemoral complications. Follow-up was from 3 to 8 years, with a mean of 5.1 years. A review of patellofemoral complications in previously reported homogeneous series of symmetrical and asymmetrical implants is presented. Mean postoperative Knee Society scores improved to 91, function scores to 86, and Hospital of Special Surgery scores to 90 yielding 95% good and excellent results. Mean postoperative range of motion was -1.5 degrees extension to 113 degrees flexion. There were five patellofemoral complications (1.4%), including two symptomatic subluxations, two distal pole avulsion fractures, and one lateral facet fracture. There were two reoperations necessary for patellofemoral problems (0.56%), one to correct subluxation and one for excision of the fractured lateral facet. These rates are lower than those previously reported for asymmetrical implants as well as current and phased-out symmetrical designs of total knee arthroplasty in the intermediate term. This review suggests that cemented total knee arthroplasty with symmetrical patellofemoral resurfacing with an offset patella dome and posterior cruciate ligament retention yields low patellofemoral complications and reoperations. The symmetrical femoral component appears to be a satisfactory compromise of "normal" femoral anatomy, which decreases inventory and cost without adversely affecting patellofemoral function and complications.     

Polycentric total knee arthroplasty. A two-year follow-up study

Polycentric total knee arthroplasty provided significant relief of pain in 86 per cent of 500 knees. The independence and activity levels of the patients increased dramatically. The frequency of major complications as reflected by reoperation was 10 per cent in this series. There was a 2.8 per cent deep infection rate. One-third of the infected knees were salvaged and two-thirds required arthrodesis. Loosening of a component was noted in 2.4 per cent. After operation the average range of motion was from 6 to 101 degrees of flexion, for a range of 95 degrees; this was a 5-degree increase over average preoperative motion. Ninety-six per cent of the patients expressed satisfaction with the surgical result.     

Prediction of postoperative knee flexion in Insall-Burstein II total knee arthroplasty

Postoperative knee flexion in patients undergoing Insall-Burstein-II total knee arthroplasty at 2 years was evaluated regarding two basic questions: what groups of patients gain or lose the most flexion and what groups of patients have the best or worst postoperative flexion. Thirteen preoperative variables (maximum flexion, flexion arc, tibiofemoral angle, quadriceps strength, extensor lag, Knee Society score, Knee Society patient assessment, gender, age, height, weight, diagnosis, and surgeon) and four postoperative variable (leg length change, tibiofemoral angle, distance from patella to the joint line, and the tibial prosthesis anteroposterior translation on a lateral radiograph) were used in an attempt to explain postoperative flexion. The analysis was performed on 164 consecutive Insall-Burstein-II total knees in which the data were gathered prospectively on a time oriented medical record database. A regression tree analysis was used to identify several groups of patients, characterized by preoperative factor values, who had markedly above average performance on postoperative flexion. The preoperative factors identified include preoperative flexion, flexion arc, tibiofemoral angle, extensor lag, diagnosis, and age. The only postoperative variable of significance was tibiofemoral angle. Among the potential determinants of postoperative flexion that failed to appear predictive were the Knee Society scores and surgeon. Preoperative flexion is known to be a critical determinant of postoperative flexion in total knee replacement. However, in the current study, preoperative flexion accounted for only half of the difference between the best (122 degrees) and the worst (88 degrees) group, as determined with regression tree analysis.     

Thickness of tibial inserts in total knee arthroplasty

The thickness of the ultrahigh-molecular-weight polyethylene used in the tibial inserts of total knee arthroplasties has become topical in recent years. A discrepancy has been found between the nomenclature of tibial inserts and the actual minimum thickness of polyethylene. Although the recommended minimum thickness is being discussed, it is important to clarify what is actually being used, with an indication to change and unify how these inserts are named.     

Clinical pathway management of total knee arthroplasty

Using a retrospective cohort study design, the authors examined complications, readmissions, morbidity and mortality, and function scores in two groups of patients attended by the same surgeon for the year before and the year after the implementation of an outcomes management program with clinical pathways for patients undergoing total knee arthroplasty at an academic health center. The effectiveness of the pathway constantly was adjusted using variance analysis and continuous quality improvement techniques. This program reduced the length of stay by 57% from a premanagement value of 10.9 +/- 5.4 days in 1994 (Group 1) to 4.7 +/- 1.4 days in 1996 (Group 2). Hospital costs (based on an inflation adjusted cost to charge ratio) for all total knees were reduced 11% from $13,328 +/- $3905 in 1994 to $11,862 +/- $4763 in 1996. Preoperative and postoperative knee scores were 41.1 +/- 16.3 and 84.2 +/- 16.0 for Group 1 and 42.5 +/- 13.0 and 87.0 +/- 10.4 for Group 2, respectively. There was no statistically significant difference between the preoperative or the postoperative knee scores of Groups 1 and 2. The application of clinical pathways, variance analysis, and continuous quality improvement toward the treatment of patients who had total knee arthroplasty at an academic health center resulted in significant savings in length of stay without adversely affecting overall outcome.     

Cement versus cementless fixation in total knee arthroplasty

A prospectively studied group of 55 uncemented Press Fit Condylar total knee arthroplasties was compared retrospectively with a matched group of 51 cemented Press Fit Condylar total knee arthroplasties at a mean of 10 years after operation. For the cemented group, the pain and function scores improved from 32 and 45 preoperatively to 95 and 77, respectively. For the uncemented group the scores improved from 33 and 50 preoperatively to 93 and 60, respectively. There were 10 revisions in the uncemented group for femoral or tibial aseptic loosening or osteolysis compared with two revisions in the cemented group. Exclusive of problems related to patellar metal backing, survival to revision for aseptic failure or radiographic loosening was 72% in the uncemented group and 94% in the cemented group at 10 years. A significantly higher revision rate was found in the uncemented compared with cemented total knee arthroplasty of the Press Fit Condylar design.     

The need for a dual rating system in total knee arthroplasty

The sequential course of the knee score and functional score of the Knee Society rating system of 276 press fit condylar modular unconstrained total knee arthroplasties performed for osteoarthritis between June 1988 and December 1992 was documented prospectively. The knee score increased significantly and stayed on a constant level from 2 years on, whereas the function score reached a maximum at 2 years and declined subsequently. Multiple regression analysis was performed testing the statistical significance and correlation of preoperative predictors with criteria at followup to determine their influence on outcome. Preoperative predictors were knee score and function score, body mass index, age, gender, patient category, and implant factors. Criteria studied were pain, knee score, and function score at 2 years followup. The function score is influenced significantly by the walking distance, age, body mass index, and patient category correlating moderately. The knee score is not affected by any of these factors. Pain was found to correlate low with the walking distance. Rating systems are influenced by numerous factors linked to the patient's general health and condition. Their impact on the overall result can be controlled by separate rating of the knee score and function score as the dual Knee Society rating system does. Scoring systems adding up knee and functional rating to an overall result should not be used. There is a need for additional improvement of total knee arthroplasty rating such as patient based evaluation and establishing reliability and validity.     

Simultaneous bilateral versus unilateral total knee arthroplasty. Outcomes analysis

One hundred consecutive, primary simultaneous bilateral total knee arthroplasties were prospectively compared with 100 consecutive, primary unilateral total knee arthroplasties in reference to relative risk, complications, cost, and need for rehabilitation. All procedures were performed using identical preoperative, intraoperative, and postoperative protocols. Postoperative confusion was approximately four times greater in the simultaneous bilateral total knee arthroplasties group (29% versus 7%), which was thought to represent an increased incidence of fat embolism. Cardiopulmonary complications were approximately three times greater after simultaneous bilateral total knee arthroplasties (14% versus 5%), and most commonly involved arrhythmias. The increased stress on the cardiopulmonary system with simultaneous bilateral total knee arthroplasties may make this procedure contraindicated in certain patients with preexisting disease. There was an approximately 17 times greater need for banked blood in the simultaneous bilateral total knee arthroplasties group (17% versus 1%), which is alarming given the persistent concerns of transfusion related disease transmission. Although the length of hospitalization was similar (6.4 days simultaneous bilateral total knee arthroplasties versus 6 days unilateral total knee arthroplasty), 89% of the patients in the simultaneous bilateral total knee arthroplasties group required a rehabilitation stay versus 45% of the patients in the unilateral total knee arthroplasty group. Total hospital charges averaged $53,168 for simultaneous bilateral total knee arthroplasties versus $32,598 for unilateral total knee arthroplasty. Total rehabilitation charges were similar. The relative cost savings implicit by doing simultaneous bilateral total knee arthroplasties seem to be at least partially offset by the approximately two times greater need for rehabilitation in this group. The true safety, efficacy, relative risk, and total cost analysis of simultaneous bilateral total knee arthroplasties demands further critical evaluation.     

The John Charnley Award. Inhibition of wear debris mediated osteolysis in a canine total hip arthroplasty model

In this study the efficacy of an oral bisphosphonate therapy to inhibit wear debris mediated bone resorption was evaluated in a canine total hip replacement model. Adult canines were randomized to three groups (n = 8 each) with a right uncemented total hip replacement performed on each animal. Group I (control) received no particulate debris. In Groups II and III, a mixture of 1 x 10(9) particles were introduced into the proximal femoral gap intraoperatively. The particle mixture consisted of fabricated ultra high molecular weight polyethylene (mean 2.3 microns, 90% by number), titanium alloy (mean 3.1 microns, 5%), and cobalt chrome alloy (mean 0.8 micron, 5%). Group III canines additionally received oral drug therapy (5 mg once a day, alendronate sodium) which was begun on postoperative Day 7 and continued until the time of sacrifice. Postoperatively, all animals were allowed 24 weeks of full ambulation before euthanasia. Radiographs obtained preoperatively, postoperatively, and at time of sacrifice were evaluated for periprosthetic osteolysis. Interfacial tissues were examined histologically and placed in organ culture and the supernatants were assayed for prostaglandin E2 and interleukin-1. One animal receiving debris (Group II) suffered a periprosthetic fracture and was sacrificed from the study. Radiographically, one of eight Group I (control) and six of seven canines from Group II (debris) had periprosthetic radiolucencies with endosteal scalloping develop. In contrast, only one of eight animals from Group III (debris + alendronate) had periprosthetic radiolucencies develop. Whereas tissues from control animals were mostly fibrous and acellular, tissues from both experimental groups had significant macrophage infiltration. Levels of prostaglandin E2 and interleukin-1 were elevated significantly in periprosthetic tissues from both experimental groups compared with controls. Continuous administration of alendronate effectively inhibited bone lysis for the 24-week duration of the study. This is consistent with the literature indicating that alendronate is incorporated in the mineralizing matrix making it refractory to osteoclastic resorption. This report has significant clinical implications for controlling the most common cause of implant failure.     

Effect of polyethylene quality on wear in total knee arthroplasty

During evaluation of 29 Ortholoc II tibial polyethylene components retrieved at revision surgery, the authors noticed that components with a lot number prefix of CP (Custom Product) consistently had minimal wear and those with a standard lot number had severe wear, regardless of patient age, weight, gender, and activity level. Non-CP components had earlier and more severe wear than CP components in service for the same amount of time. Microscopic evaluation of the polyethylene revealed major differences in the material. Large subsurface cracks, fusion defects, and intergranular cracks were present in the non-CP components, but these defects were minimal or nonexistent in the CP components. The components with defects had a significantly greater delamination rate than those without defects. Gamma irradiation did not seem to accelerate wear or delamination, because irradiated components that had minimal microscopic signs of fusion defects performed as well as nonirradiated components with a similar microscopic appearance. The manufacturing details disclosed that different materials and processing methods were used for the 2 groups. The results from this study suggest that improved quality control of polyethylene material would greatly decrease wear and delamination of total knee arthroplasty components.     

Role of the posterior cruciate ligament in total knee arthroplasty

Accumulating evidence indicates that protein kinase C (PKC)-dependent, Ca2+-independent smooth muscle contraction plays the central role in the occurrence of chronic vasospasm following aneurysmal subarachnoid hemorrhage. As far as we know, the nitric oxide/ cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) system comprises the most efficacious inhibitory mechanism against the PKC-dependent contractile mechanism, and the myogenic tonus of normal cerebral arteries is thought to be maintained on the balance between these systems. Recent studies indicate that in spastic cerebral arteries, the rise in the intracellular diacylglycerol level causes PKC activation presumably owing to the overexpression of endothelin (ET)-1 as well as the generation of free radicals, whereas the cGMP level is inversely reduced owing to the inactivation of soluble guanylate cyclase through some as yet unknown mechanism. The resultant loss of balance between the two systems is considered to culminate in the occurrence of chronic vasospasm lasting for nearly 2 weeks. Based on the above concept, recent papers concerning the effects of reactive oxygen species on the arterial smooth muscle, alterations of various membrane ion channels, particularly of adenosine triphospate (ATP)-activated potassium channels in spastic arteries, the preventive effects of ET antagonists on vasospasm, and the causative role of ET-1 were reviewed in the present article. The roles of the above spasmogenic factors or mechanisms may be more clearly understood on the basis of the antagonistic interrelation between the PKC and the PKG systems, which exert diverse influences on the force-generating system as well as on its multifarious regulatory mechanisms in smooth muscle cells.     

Treatment of major defects of bone with bulk allografts and stemmed components during total knee arthroplasty

We reviewed the results an average of fifty months (range, twenty-four to 120 months) after the use of thirty-five allografts in thirty patients during primary or revision total knee replacement. Twenty-nine femoral-head allografts, five distal femoral allografts, and one proximal tibial allograft were used in conjunction with a long-stemmed implant to reconstruct large osseous defects. The patients were evaluated clinically, radiographically, and subjectively (with use of a questionnaire). Twenty-six (87 per cent) of the thirty patients had a good or excellent clinical result, and no revisions were necessary. As none of the patients had collapse of the graft, subsidence of the implant, or revision, we believe that the outcome of treatment with a femoral-head allograft, particularly in association with a component inserted with cement, is excellent. Four non-porous-coated components were placed without cement on structural allografts. Radiographically, three of those components subsided, but none of the three needed revision and two were associated with a good clinical result. Our current practice is to cement components in all arthroplasties involving grafting. Our findings suggest that the use of a stemmed component reduces the stress on the allograft, host bone, and fixation interface. In addition, such a component contributes to the longevity of a total knee replacement associated with a bone graft. Additional studies with long-term follow-up are necessary to confirm this outcome.     

Intravenous regional analgesia using morphine. The effect on postoperative pain following total knee arthroplasty

BACKGROUND: We hypothesised that any peripheral action of morphine may contribute to improved postoperative analgesia. The aim of this study was to evaluate the analgesic efficacy of morphine administered preoperatively into an exsanguinated limb prior to total knee arthroplasty. METHODS: A randomised, double-blind, controlled study was performed in 50 patients having total knee arthroplasty surgery. Patients were divided into two groups. In the study group, 0.125 mg/kg morphine in 60 ml of saline was administered intravenously (iv) into the exsanguinated operative limb via a cannula in the foot. A saline intramuscular (im) injection was administered into the opposite leg. The control group received 60 ml saline iv into the operative leg and 0.125 mg/kg morphine im into the opposite leg. Pain was assessed postoperatively using a 10-point visual analogue scale and by comparing morphine requirements and demand:delivery ratios from a patient-controlled analgesic pump. RESULTS: We found no statistically significant difference between the groups in relation to any of the analgesic measures employed. CONCLUSIONS: Intravenous regional analgesia using morphine provides no analgesic advantage over the intramuscular route from 6-24 h postoperatively.