Jean-Manuel Aubaniac

Modern unicompartmental knee arthroplasty with cement: a three to ten-year follow-up study.

Background: Unicompartmental arthroplasty is a treatment alternative when only one compartment of the knee is affected with arthritis, but the reported results of this procedure have been variable. The purpose of the present study was to evaluate the results of a modern unicompartmental knee arthroplasty performed with use of a cemented metal-backed prosthesis and surgical instrumentation comparable with that used for total knee replacement.Methods: The indications for the procedure were osteonecrosis or osteoarthritis associated with full-thickness loss of cartilage that was limited to one tibiofemoral compartment as evaluated on standing and stress radiographs. One hundred and sixty consecutive cemented metal-backed Miller-Galante prostheses in 147 patients were evaluated after a mean duration of follow-up of sixty-six months (range, thirty-six to 112 months). The mean age of the patients at the time of the index procedure was sixty-six years.Results: Three knees were revised because of progression of osteoarthritis in the patellofemoral joint (two knees) or the lateral tibiofemoral compartment (one knee). Two knees had revision of the polyethylene liner. The average Hospital for Special Surgery knee score improved from 59 points preoperatively to 96 points at the time of the review. According to Kaplan-Meier analysis, the ten-year survival rate (with twenty-nine knees at risk) was 94% ± 3% with revision for any reason or radiographic loosening as the end point.Conclusions: A modern unicompartmental knee arthroplasty is a valid alternative for patients with unicompartmental tibiofemoral noninflammatory disease. The patient selection must be strict with regard to the status of the patellofemoral joint. The preoperative planning includes stress radiographs to assess the correction of the deformity and the status of the uninvolved compartment. Continued long-term follow-up is necessary to evaluate long-term polyethylene wear.

Is there a place for patellofemoral arthroplasty

Indications for patellofemoral arthroplasty were studied based on a 2− to 10-year followup review. Of 183 patellofemoral prostheses implanted between 1980 and 1990,104 were associated with unicompartmental arthroplasty, and 79 were implanted alone. Thirteen patients were lost to followup. The results of 66 patellofemoral arthroplasties are reported at an average followup of 66 months. The mean age of the patients at surgery was 57 years. Underlying causes of the osteoarthritis included patellar dislocation or dysplasia (22), patellar fracture (20), and primary osteoarthritis (24). A metallic femoral groove was associated with a polyethylene patella with no metal backing. Two (9%) prostheses were revised in the dysplasia group, 1 (5%) in the posttraumatic group, and 7 (29%) in the primary osteoarthritis group. In this latter group, the indications of patellofemoral arthroplasty must be restricted to lesions of the patellofemoral joint in a knee in neutral axis evaluated preoperatively on full standing and stress radiographs. The best results of patellofemoral arthroplasty were obtained in osteoarthritis after patellar dislocation or patellar fracture.

A 12-28-year followup study of closing wedge high tibial osteotomy.

Current indications for high tibial osteotomy (HTO) are controversial although several risk factors have been associated with HTO survival. We ascertained the influence of preoperative variables in a consecutive series of patients who had closing wedge HTO at a minimum of 12 year followup (mean 18-year, range 12 to 28 years). Three hundred one of an initial 372 high tibial osteotomies (313 patients) were included (81% followup); 71 knees were eliminated because patients died (30 knees) or were lost to followup (41 knees). The mean age was 42 years (range, 15-76 years), 194 were men and 119 were women. The osteotomy was fixed by a Blount staple and an AO half-tube plate with three screws. Forty-three knees (14%) in 39 patients were revised for progression of osteoarthritis at an average of 102 months. Survival was 85% at 20 years with revision as the endpoint. Knee function was considered satisfactory by 77% of patients. At final followup, ½ of the knees showed radiographic signs of medial osteoarthritis. The most important risk factors predicting revision were age greater than 50 years and a preoperative arthritis Ahlback grade of 3 or more. Level of Evidence: Level IV, therapeutic study (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Patellofemoral arthroplasty: an update.

The rationale for presenting this updated study is to report long-term clinical and survival results of patellofemoral arthroplasty and to ascertain whether the preoperative diagnosis influenced outcomes and therefore indications. We retrospectively updated a previous evaluation of 66 patients who had unilateral patellofemoral arthroplasty between 1972 and 1990. The mean age of the patients at the initial surgery was 57 years (range, 21-82 years). The patients had an average followup of 16.2 years (range, 12-20 years). Preoperative diagnosis included instability, fracture, and primary arthritis. Revision surgery was done in 14 patients for femorotibial osteoarthritis, in 11 for loosening, and in four for stiffness. Survivorship was 58% at 16 years. The knee function score improved from 40 points preoperatively to 81 points at last followup. The best results were in patients with preoperative instability and corrected alignment of the extensor mechanism. Stiffness occurred only in those patients with osteoarthritis from previous fracture. Progressive degeneration of the tibiofemoral joint was noted mainly in the primary osteoarthritis etiologic group. This long-term evaluation of patellofemoral arthroplasty showed the importance of patient selection while excluding knees with significant frontal tibiofemoral malalignment. Level of Evidence: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

A high flexion total knee arthroplasty design replicates healthy knee motion.

Deep flexion affects both femorotibial contact pattern and the patellofemoral articulation. The purpose of this study was to compare the patellofemoral motion of nonimplanted and implanted knees and to analyze femorotibial kinematics after total knee replacement designed for deep flexion. Three-dimensional patellofemoral kinematics were evaluated during a deep knee bend using fluoroscopy for five control patients with a healthy knee, five patients with an anterior-cruciate-ligament-deficient knee, and 20 patients who had a high flexion total knee arthroplasty. Less translation of patellofemoral contact position was seen in patients who had knee replacements than in patients with healthy knees, but the average motion and the patella tilt angles were similar to the healthy knees. On average, patients who had a total knee arthroplasty had 4.9° normal axial rotation, and all patients had at least −4.4 mm of posterior femoral rollback. The average weightbearing range of motion of the patients in the total knee arthroplasty group was 125°. In this study, patients implanted with a high-flexion knee replacement design had kinematic patterns that were similar to the healthy knee. It can be hypothesized that forces acting on the patella were not substantially increased for patients who had a total knee arthroplasty compared with the control patients.

Anatomy of the Dysplastic Hip and Consequences for Total Hip Arthroplasty

Total hip arthroplasty in dysplastic hips is challenging because of the modified anatomy of the proximal femur and acetabulum. We studied three-dimensional anatomic parameters in 247 dysplastic hips from 218 adult patients using radiographs and computed tomography, and analyzed the consequences for total hip arthroplasty. A cohort of 310 primary osteoarthritic hips was used as a control group. According to the classification of Crowe et al, 78 of the dislocated hips were graded Class I, 26 as Class II, 20 as Class III or IV, and 169 dysplastic hips had no subluxation. Compared with primary osteoarthritis, the intramedullary femoral canal had reduced mediolateral and anteroposterior dimensions. With high grade subluxations the femoral neck shaft angle decreased but with low grades, especially in Class II, the neck shaft angle increased. The proximal femur had more anteversion with individual variations ranging from 1° to 80°. The true acetabulum had a reduced anteroposterior diameter. The large individual morphologic variability across all levels of dysplastic hips suggests the femoral prosthesis cannot be chosen on the basis of the severity of the subluxation alone.

Modern unicompartmental knee arthroplasty with cement: a concise follow-up, at a mean of twenty years, of a previous report.

We previously evaluated the three to ten-year results of 160 consecutive unicompartmental knee arthroplasties that had been performed by two surgeons in 147 patients with use of the cemented metal-backed Miller-Galante prosthesis. The average age of the patients at the time of the index procedure was sixty-six years. The purpose of the present study was to report the updated results of this series after a mean duration of follow-up of twenty years. Sixty-two patients (seventy knees) were living, and seven had been lost to follow-up. Eleven knees had undergone conversion to total knee arthroplasty, three had had an addition of a patellofemoral prosthesis, and five had had polyethylene exchange. Ten knees had had revision since the three to ten-year evaluation. The reasons for revision included progression of osteoarthritis in twelve knees, aseptic loosening (which had been absent at the three to ten-year evaluation) in two knees, and polyethylene wear (which was treated with liner exchange at an average of twelve years) in five knees. The average clinical and functional Knee Society scores were 91 and 88 points, respectively, at the time of the latest follow-up. The average flexion was 127° (range, 80° to 145°). We concluded that modern cemented metal-backed unicompartmental implants, evaluated at a mean of twenty years of follow-up in patients with osteoarthritis that was limited to one tibiofemoral compartment of the knee, provided durable pain relief and long-term restoration of knee function without compromising future conversion to conventional total knee arthroplasty.

Medial unicompartmental knee replacement in the under-50s

We retrospectively reviewed 35 cemented unicompartmental knee replacements performed for medial unicompartmental osteoarthritis of the knee in 31 patients </=50 years old (mean 46, 31 to 49). Patients were assessed clinically and radiologically using the Knee Society scores at a mean follow-up of 9.7 years (5 to 16) and survival at 12 years was calculated. The mean Knee Society Function Score improved from 54 points (25 to 64) pre-operatively to 89 (80 to 100) post-operatively (p < 0.0001). Six knees required revision, four for polyethylene wear treated with an isolated exchange of the tibial insert, one for aseptic loosening and one for progression of osteoarthritis. The 12-year survival according to Kaplan-Meier was 80.6% with revision for any reason as the endpoint. Despite encouraging clinical results, polyethylene wear remains a major concern affecting the survival of unicompartmental knee replacement in patients younger than 50.

Three-dimensional anatomy of the hip in osteoarthritis after developmental dysplasia

Using radiography and computer tomography (CT) we studied the morphology of 83 hips in 69 Caucasian adults with osteoarthritis secondary to developmental dysplasia of the hip (DDH). A previously published series of 310 hips with primary osteoarthritis was used as a control group. According to the Crowe classification, 33 of the dysplastic hips were graded as class I, 27 as class II and 23 as class III or class IV. The intramedullary femoral canal had reduced mediolateral and anteroposterior dimensions in all groups compared with the control group. Only in Crowe class II hips was the femoral neck-shaft angle increased. The proximal femur had more anteversion in all the developmental dysplasia of the hip groups, ranging from 2 degrees to 80 degrees. Templated measurement of acetabular dimensions for plain radiography closely matched measurements taken by CT. The results of our study confirm the observations previously confined to the Japanese population.

Unicompartmental knee arthroplasty for avascular osteonecrosis.

The data analyzing clinical and radiological outcomes after modern unicompartmental knee arthroplasty (UKA) for spontaneous and secondary avascular osteonecrosis are limited. We determined whether: (1) UKA for osteonecrosis was as reliable for alleviating pain and improving function (measured by Knee Society scores) as it is for osteoarthritis, (2) lower limb alignment could be restored after UKA for osteonecrosis, and (3) UKA for osteonecrosis is as durable as UKA for osteoarthritis (measured by survivorship at 12 years). We retrospectively reviewed 30 patients (31 knees) with osteonecrosis; 21 knees had spontaneous osteonecrosis and 10 had secondary osteonecrosis. Mean patient age was 71 years. Clinical and radiological evaluations were performed by an independent observer at a minimum followup of 3 years (mean, 7 years; range, 3-16 years). Reliable pain relief and function improvement were obtained in 30 knees (96%). Restoration of an appropriate lower-limb mechanical axis was achieved for 27 knees (88%). The Kaplan-Meier survivorship was 96.7% at 12 years. Our data suggest UKA is a reasonable solution for restoring clinical function and radiological lower-limb alignment for spontaneous or secondary osteonecrosis limited to one compartment of the knee, with a durable survivorship.Level of Evidence: Level IV, retrospective study. See the Guidelines for Authors for a complete description of levels of evidence.