Aaron G. Rosenberg

Results of Unicompartmental Knee Arthroplasty at a Minimum of Ten Years of Follow-up

BACKGROUND There is a renewed interest in unicompartmental knee arthroplasty. The present report describes the minimum ten-year results associated with a unicompartmental knee arthroplasty design that is in current use. METHODS Sixty-two consecutive unicompartmental knee arthroplasties that were performed with cemented modular Miller-Galante implants in fifty-one patients were studied prospectively both clinically and radiographically. All patients had isolated unicompartmental disease without patellofemoral symptoms. No patient was lost to follow-up. Thirteen patients (thirteen knees) died after less than ten years of follow-up, leaving thirty-eight patients (forty-nine knees) with a minimum of ten years of follow-up. The average duration of follow-up was twelve years. RESULTS The mean Hospital for Special Surgery knee score improved from 55 points preoperatively to 92 points at the time of the final follow-up. Thirty-nine knees (80%) had an excellent result, six (12%) had a good result, and four (8%) had a fair result. At the time of the final follow-up, thirty-nine knees (80%) had flexion to at least 120 degrees . Two patients (two knees) with well-fixed components underwent revision to total knee arthroplasty, at seven and eleven years, because of progression of patellofemoral arthritis. At the time of the final follow-up, no component was loose radiographically and there was no evidence of periprosthetic osteolysis. Radiographic evidence of progressive loss of joint space was observed in the opposite compartment of nine knees (18%) and in the patellofemoral space of seven knees (14%). Kaplan-Meier analysis revealed a survival rate of 98.0% +/- 2.0% at ten years and of 95.7% +/- 4.3% at thirteen years, with revision or radiographic loosening as the end point. The survival rate was 100% at thirteen years with aseptic loosening as the end point. CONCLUSIONS After a minimum duration of follow-up of ten years, this cemented modular unicompartmental knee design was associated with excellent clinical and radiographic results. Although the ten-year survival rate was excellent, radiographic signs of progression of osteoarthritis in the other compartments continued at a slow rate. With appropriate indications and technique, this unicompartmental knee design can yield excellent results into the beginning of the second decade of use.

Primary total hip reconstruction with a titanium fiber-coated prosthesis inserted without cement

A prospective study was done of the intermediate-term clinical and radiographic results of 121 total hip arthroplasties in which a Harris-Galante porous titanium-fiber-coated prosthesis was inserted without cement in 110 patients. The average age at the time of the operation was forty-nine years (range, twenty to seventy years). The average duration of follow-up was sixty-seven months (range, fifty-five to seventy-nine months). The average preoperative Harris hip score was 55 points, and the average postoperative score was 93 points. One acetabular component was revised due to recurrent dislocation. Eleven femoral implants were unstable, and of these, four were revised. Cortical erosion was present around the distal part of the femoral stem in nine patients (8 per cent) who had stable implants, and one of these femoral implants was revised because the erosion was extensive. Survivorship analysis at five years revealed a 97 per cent chance of survival (95 per cent confidence limit, 0.937 to 1.0) of the Harris-Galante femoral-stem implant inserted without cement.

Rapid rehabilitation and recovery with minimally invasive total hip arthroplasty.

To assess the potential recovery rate of a minimally invasive total hip replacement technique with minimal soft tissue disruption, an accelerated rehabilitation protocol was implemented with weightbearing as tolerated on the day of surgery. One hundred consecutive patients were enrolled in this prospective study. Ninety-seven patients (97%) met all the inpatient physical therapy goals required for discharge to home on the day of surgery; 100% of patients achieved these goals within 23 hours of surgery. Outpatient therapy was initiated in 9% of patients immediately, 62% of patients by 1 week, and all patients by 2 weeks. The mean time to discontinued use of crutches, discontinued use of narcotic pain medications, and resumed driving was 6 days postoperatively. The mean time to return to work was 8 days, discontinued use of any assistive device was 9 days, and resumption of all activities of daily living was 10 days. The mean time to walk ½ mile was 16 days. Furthermore, there were no readmissions, no dislocations, and no reoperations. Therefore, a rapid rehabilitation protocol is safe and fulfills the potential benefits of a rapid recovery with minimally invasive total hip arthroplasty.

Unicompartmental knee arthroplasty. Clinical experience at 6- to 10-year followup.

Sixty-two consecutive cemented modular unicompartmental knee arthroplasties in 51 patients were studied prospectively. At surgery, the other compartments had at most Grade 2 chondromalacia. The average age of the patients at arthroplasty was 68 years (range, 51-84 years). One patient was lost to followup and 10 died with less than 6 years followup. The average followup of the remaining 51 knees was 7.5 years (range, 6-10 years). The preoperative Hospital for Special Surgery knee score of 55 points (range, 30-79 points) improved to 92 points (range, 60-100 points) at followup; 78% (40 knees) had excellent and 20% (10 knees) had good results. The mean range of motion at followup was 120 degrees with 26 knees (51%) having range of motion greater than 120 degrees. One patient underwent revision surgery for retained cement, one patient underwent knee manipulation, and one patient underwent revision surgery at 7 years for opposite compartment degeneration and pain. Radiographically, 26 knees (51%) had at least one partial radiolucency. There were no complete femoral radiolucencies, but there were three complete tibial radiolucencies, all less than 2 mm. No component was loose as seen on radiographs. At final followup, five of the opposite compartments (10%) and three of the patellofemoral joints (6%) had some progressive radiographic joint space loss; this was less than a 25% loss in all but one knee component that was revised. At 6- to 10-years followup, cemented unicompartmental knee arthroplasty yielded excellent clinical and radiographic results. The 10-year survival using radiographic loosening or revision as the end point was 98%. Using stringent selection criteria, unicompartmental knee replacement can yield excellent results and represents a superb alternative to total knee replacement.

Changing demographics of patients with total joint replacement.

There has been a substantial change in the population demographics of patients who potentially will require total joint replacements. We studied data regarding temporal trends in physical condition, life expectancy, education, and other population demographics of individuals most likely to receive total joint replacements. Changes in this population during the last several decades correlate with temporal changes in the prevalence of joint disease and the incidence of total hip and knee replacements. Compared with several decades ago, patients currently receiving total joint replacements are almost 20% heavier, more physically active, three times more likely to have a high school or college education, and live more than 25% longer. Patients needing total joint replacements are more likely to be female, and twice as likely to receive a total knee replacement than a total hip replacement. Treatment choices and outcome expectations are best determined with accurate knowledge of current surgical science and current patient demographics. Therefore, it is important to realize that todays population most likely to receive total joint replacements is demographically different than in the past.

Patellar component failure in cementless total knee arthroplasty.

One hundred twenty-two total knee arthroplasties were performed with porous ingrowth fixation of the patellar component between February 1984 and February 1987. Twelve subsequently have experienced fatigue fracture of the patellar component at the peg-plate junction. All fractured patellar components demonstrated excellent ingrowth and fixation of the porous titanium fiber mesh-peg surfaces with no ingrowth into the porous plate underlying the polyethylene patellar surface. While the initial group of 122 arthroplasties was only slightly greater than one-third male, the preponderance of patellar fractures was in males (ten of 12). Patients with patellar component failure were on average younger and heavier and had a greater range of knee motion than the index group. The average time from implantation to recognition of fracture was 24 months. Biomechanical analysis of the force system about a domed patella demonstrated that loading of the patellofemoral joint results in eccentric loading of the dome surface. Peg fixation not accompanied by fixation of the overlying plate allows these high eccentric forces to load the peg-plate junction in shear with consequent fatigue at the peg-plate junction. These results indicate that the shear forces are sufficiently high to warrant caution in the use of peg-plate systems in which peg ingrowth without plate ingrowth occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

Second-generation cementless total hip arthroplasty. Eight to eleven-year results.

Background: Second-generation cementless femoral components were designed to provide more reliable ingrowth and to limit distal osteolysis by incorporating circumferential proximal ingrowth surfaces. We examined the eight to eleven-year results of total hip arthroplasty with a cementless, anatomically designed femoral component and a cementless hemispheric acetabular component. Methods: Ninety-two consecutive primary total hip arthroplasties with implantation of a femoral component with a circumferential proximal porous coating (Anatomic Hip) and a cementless hemispheric porous-coated acetabular component (Harris-Galante II) were performed in eighty-five patients. These patients were prospectively followed clinically and radiographically. Six patients (seven hips) died and five patients (seven hips) were lost to follow-up, leaving seventy-four patients (seventy-eight hips) who had been followed for a mean of ten years (range, eight to eleven years). The mean age at the time of the arthroplasty was fifty-two years. Results: The mean preoperative Harris hip score of 51 points improved to 94 points at the time of final follow-up; 86% of the hips had a good or excellent result. Thigh pain was reported as mild to severe after seven hip arthroplasties. No femoral component was revised for any reason, and none were loose radiographically at the time of the last follow-up. Two hips underwent acetabular revision (one because of dislocation and one because of loosening). Kaplan-Meier survivorship analysis was performed with revision or loosening of any component as the end point. The ten-year survival rate was 96.4% ± 2.1% for the total hip prosthesis, 100% for the femoral component, and 96.4% ± 2.1% for the acetabular component.Radiolucencies adjacent to the nonporous portion of the femoral component were seen in sixty-eight (93%) of the -seventy-three hips with complete radiographic follow-up. Femoral osteolysis proximal to the lesser trochanter was noted in four hips (5%). No osteolysis was identified distal to the lesser trochanter. Periacetabular osteolysis was identified in twelve hips (16%). Five patients underwent exchange of the acetabular liner because of polyethylene wear. Conclusions: This second-generation cementless, anatomically designed femoral component provided excellent clinical and radiographic results with a 100% survival rate at ten years. The circumferential porous coating of this implant improved ingrowth and prevented distal osteolysis at a mean of ten years after the arthroplasty.

Prevention of Deep-Vein Thrombosis after Total Hip Arthroplasty. Comparison of Warfarin and Dalteparin*

The effectiveness and safety of warfarin were compared with those of a low-molecular-weight heparin (dalteparin) for the prevention of deep-vein thrombosis after total hip arthroplasty in a prospective, randomized, multi-institutional trial. Patients who were older than eighteen years of age and were scheduled to have an elective primary or revision total hip arthroplasty were eligible; 580 patients were randomized, 550 had the operation and received prophylaxis, and 382 had evaluable venograms. Prophylaxis was provided either with warfarin beginning the night before the operation or with dalteparin beginning two hours before the operation and was continued until venography was performed. Bleeding was assessed on the basis of intraoperative blood loss, transfusion requirements, a decrease in hematocrit, and clinically identified bleeding complications. The prevalence of deep-vein thrombosis was found to be significantly lower in the patients who had received dalteparin than in those who had received warfarin (twenty-eight [15 per cent] of 192 patients compared with forty-nine [26 per cent] of 190 patients; p = 0.006). Deep-vein thrombosis occurred in the calf veins of twenty-one patients (11 per cent) who had received dalteparin and of forty-three patients (23 per cent) who had received warfarin; this difference was significant (p = 0.003). Proximal deep-vein thrombosis occurred in ten patients (5 per cent) who had received dalteparin and in sixteen patients (8 per cent) who had received warfarin; however, with the numbers available, no significant difference could be detected (p = 0.185). We also could not detect a significant difference with regard to the intraoperative and postoperative blood loss, the decrease in hematocrit, and the prevalence of major bleeding complications between the two groups; however, the patients who had received dalteparin had a significantly higher prevalence of bleeding complications involving the operative site (p = 0.03), and a significantly greater percentage required postoperative transfusions (p = 0.001). We concluded that preoperative prophylaxis with dalteparin is significantly more effective than that with warfarin in preventing deep-vein thrombosis after total hip arthroplasty. The greater effectiveness of dalteparin must be considered, however, in light of an increased need for postoperative transfusions and an increase in the prevalence of wound-related bleeding complications.

Long-term followup of the Miller-Galante total knee replacement

One hundred seventy-two consecutive cemented Miller-Galante-I total knee arthroplasties in 155 patients were compared with 109 consecutive cemented Miller-Galante-II total knee arthroplasties in 92 patients. The average followup was 11 years (range, 8–15 years) and 9 years (range, 8–10 years), respectively. Of the 172 Miller-Galante-I arthroplasties, there have been 21 revisions; 15 patellar revisions; two included femoral revisions attributable to abrasion. Six additional well-fixed femoral and tibial components were revised: two for early instability, one for pain, one for periprosthetic fracture, and two for infection. No component had aseptic loosening or osteolysis. Using revision or loosening of any components as the end point, the Kaplan-Meier 10-year survivorship was 84.1% ± 4.1%. Of the 109 Miller-Galante-II arthroplasties, there have been no component revisions, no aseptic loosening, and no osteolysis. Using revision or loosening of any components as the end point, the Kaplan-Meier 10-year survivorship was 100%. The Miller-Galante knee systems showed excellent fixation with no loosening and no osteolysis at as many as 15 years. Additionally, there have been no component revisions for late instability at as many as 15 years. Finally, the high prevalence of patellofemoral complications with the Miller-Galante-I design has been obviated with the Miller-Galante-II design.

Revision of the acetabular component without cement after total hip arthroplasty. Three to six-year follow-up.

One hundred and thirty-eight consecutive revisions of an acetabular component were performed in 132 patients between 1983 and 1986. The revision prosthesis was a hemispherical component that was coated with porous titanium mesh and was secured to the pelvis with a variable number of screws. There were seventy-five women and fifty-seven men, and the mean age at the time of the revision was fifty-two years (range, twenty to seventy-nine years). Due to defects in the acetabulum, 80 per cent of the hips were treated with bone grafts, usually a mixture of local autogenous graft and freeze-dried allograft. One hundred and twenty-four patients (129 hips) were available for follow-up, at a mean of forty-four months (range, thirty-six to eighty months). Seven hips (5 per cent) were revised again: four because of infection and three because of instability. There were no revisions for loosening without infection, and none of the components migrated in the absence of infection. Radiolucent lines were common and usually corresponded to regions in which allograft had been used. All bone grafts united by twelve months. Non-contained medial grafts underwent a phenomenon of resorption, consolidation, and remodeling to a sclerotic rim by twenty-four months. There were no complications related to placement of the screws. The results in this series were superior to results of revisions of acetabular components with the use of cement, which were associated with rates of failure of almost 10 per cent after a similar duration of follow-up. The technique of maximization of host-bone coverage and of packing of all defects with cancellous autogenous graft or allograft, or both, was successful for all classes of acetabular deficiencies.