Results of Unicompartmental Knee Arthroplasty With Cemented,Fixed-Bearing Prosthesis Using Minimally Invasive Surgery

The aim of this study was to evaluate the intermediate-term survivorship of cemented fixed-bearing unicompartmental knee arthroplasty (UKA). One hundred twenty-eight consecutive UKAs in 98 patients were performed by a single surgeon with “Allegretto” UKA prostheses. Six patients died and 5 were lost to follow-up, leaving 87 patients (116 knees) with an average follow-up of 5.7 years (range, 3-8 years). At the latest follow-up, the survival rate was 92.2%; average clinical and functional knee society scores improved from 50 and 64 points preoperatively to 89 and 88 points, respectively; and average total knee score was 171 (range, 94-200). Radiographic follow-up demonstrated average alignment of 3° valgus (range, 6° varus to 7° valgus). Ninety-two percent of the patients indicated satisfaction with the procedure. Nine knees failed requiring revision at an average of 40.4 months. We are encouraged with the satisfactory results, considering the broader spectrum of selected patients.     

The use of structural allograft for uncontained defects in revision total knee arthroplasty. A minimum five-year review

BACKGROUND: To our knowledge, the medium to long-term outcome after revision knee arthroplasty with structural allograft augmentation for reconstruction of uncontained defects has not been determined. The purpose of the present study was to assess the outcome for patients managed with such a procedure. METHODS: We prospectively followed fifty patients who had fifty-two revision knee replacements with sixty-six structural grafts performed at three institutions. Twenty-nine knees (twenty-seven patients) were independently evaluated at a mean of 96.9 months (range, sixty to 189 months) by an investigator who had not been involved in the index procedure. Twelve knees (23%) had a repeat revision at a mean of 70.7 months (range, twenty-six to 157 months). The allograft was retained in two of these patients. Eleven patients died at a mean of ninety-three months (range, sixty-one to 128 months) after the procedure; the structural allograft and implants were intact, and the patients were not awaiting revision at the time of death. RESULTS: Clinical evaluation revealed that the mean modified Hospital for Special Surgery knee score had improved from 32.5 points preoperatively to 75.6 points at the time of the review and the mean range of motion had increased from 60.5 degrees preoperatively to 88.6 degrees. Failure was defined as an increase of less than 20 points in the modified Hospital for Special Surgery knee score at the time of the review or the need for an additional operation related to the allograft. Thirteen knee replacements failed, yielding a 75% success rate. Five knees had graft resorption, resulting in implant loosening. Four knee replacements failed because of infection, and two knees had nonunion between the host bone and the allograft. Two knees (one patient) did not have a 20-point improvement in the knee score. The survival rate of the allografts was 72% (95% confidence interval, 69% to 75%) at ten years. On radiographic analysis, none of the surviving grafts had severe resorption, one had moderate resorption, and two had mild resorption. One knee had a loose tibial component, and three knees had nonprogressive tibial radiolucent lines. All four knees were asymptomatic. CONCLUSIONS: Our results demonstrate that allografts used in revision knee replacement in patients with the difficult problem of massive bone loss have an encouraging medium-term rate of survival.     

Advantage of Minimal Anterior Knee Pain and Long-term Survivorship of Cemented Single Radius Posterior-Stabilized Total Knee Arthroplasty without Patella Resurfacing

BackgroundThe single radius total knee prosthesis was introduced with the advantage of reduced patellar symptoms; however, there is no long-term follow-up study of the same. The purpose of this study was to determine the survival rate of single radius posterior-stabilized total knee arthroplasty and patellofemoral complication rates in a consecutive series.MethodsSeventy-one patients (103 knees) who underwent arthroplasty without patellar resurfacing using a single radius posterior-stabilized total knee prosthesis were followed up for a minimum 10 years. Clinical evaluation using Knee Society knee and function scores and radiologic evaluation were performed at regular intervals. Anterior knee pain as well as patellofemoral complications were evaluated with a simple questionnaire. The Kaplan-Meier product-limit method was used to estimate survival.ResultsSeventeen patients (23 knees) were excluded due to death (12 knees) or lost to follow-up (11 knees). Of the 80 knees enrolled, all femoral components and 78 tibial components were well fixed without loosening at final follow-up. Two revisions were performed because of tibial component loosening and periprosthetic joint infection. One patient with tibial component loosening refused to have revision surgery. No obvious tibial insert polyethylene wear was observed. The survivorships at 132 months were 96.7% using revision or pending revision as end points. Anterior knee pain was present in 6 patients (6 knees, 7.5%) at the latest follow-up. No patellofemoral complication requiring revision was encountered.ConclusionsThe single radius posterior-stabilized total knee prosthesis demonstrated an excellent minimum 10-year survivorship. The low rates of implant loosening and 7.5% of anterior knee pain as a patellofemoral complication are comparable with those reported for other modern total knee prosthesis.     

Osteolysis of the distal femur after total knee arthroplasty

An 11.1% incidence of femoral osteolysis (30 cases in 28 patients) was identified in a series of 271 primary total knee arthroplasties. Two minimally constrained total knee designs (Synatomic [Depuy, Warsaw, IN] and Porous-Coated Anatomic [PCA, Howmedica, Rutherford, NJ]) were used in this patient population. Femoral osteolysis was observed in 26 Synatomic and 4 PCA knees. The average follow-up period was 52 months (range, 24–96 months). Osteolytic lesions were identified radiographically, adjacent to the nonporous-coated (smooth) regions of the anterior and posterior flanges of the Synatomic and PCA femoral components. The average time to the diagnosis of femoral osteolysis was 31 months (range, 7–96 months). The average patient age at the time of primary total knee arthroplasty was 63 years (range, 43–83 years) and the average weight was 180 lb. (range, 107–278 lb.). Sixteen of the 30 cases were in men. All of the cases with femoral osteolysis had cementless implantation. Tissue specimens were obtained from the 18 cases requiring revision. Implants remained in situ an average of 66 months (range, 15–96 months) prior to revision. In 16 of the 18 cases revised, the femoral component was clinically and radiographically stable. Six of 18 cases were revised for severe osteolysis. The remaining 12 cases were revised for failed metal-backed patellae, failed cementless tibial fixation, or advanced polyethylene wear. Wear of the thin tibial inserts and patellar components were the two sources of particulate polyethylene. Polyethylene debris was observed in all tissue specimens. In cases with failed metal-backed patellae or impingement of the tibial locking pin-and-clip, fine metallic debris was also noted in tissue specimens. Microscopic evaluation of the osteolytic tissue revealed a florid histiocytic response with occasional giant cells. Intracellular submicron particulate polyethylene was identified with polarized light microscopy and oil-red-O staining techniques. In the study population, statistically significant factors associated with femoral osteolysis included male gender (P < .05), younger age (P < .05), increased patient weight (P < .05), positive tibial osteolysis (P < .001), osteoarthritis (P < .07), and length of time in situ (P < .001). In addition, patients with a Synatomic prosthesis were at increased risk for osteolysis compared to patients with a PCA device (P < .02). The authors postulate that histiocytic granuloma gained access to the proximal femur primarily via the unbonded interface between the smooth metal and bone.     

Influence of polyethylene constraint on tibial component fixation in total knee arthroplasty: follow-up report after 5 years

The influence of articulating surface design of AMK total knee prosthesis (DePuy, Johnson & Johnson) on migration and radiographic outcome at 5 years was evaluated. The knees were randomly allocated to receive a flat or a concave insert with retention of the posterior cruciate ligament when preoperative deformity was less severe and either a concave or a posterior-stabilized insert with resection of the posterior cruciate ligament when deformity was more pronounced. In 64 knees, migration was measured with radiostereometry. The posterior-stabilized component displayed more varus-valgus tilting than the concave insert. Other statistically significant differences in migration were not seen. Radiolucent lines were frequently seen without differences between prosthesis groups.     

Medial-to-Lateral Ratio of Tibiofemoral Subchondral Bone Area is Adapted to Alignment and Mechanical Load

Malalignment is known to affect the medial-to-lateral load distribution in the tibiofemoral joint. In this longitudinal study, we test the hypothesis that subchondral bone surface areas functionally adapt to the load distribution in malaligned knees. Alignment (hip–knee–ankle angle) was measured from full limb films in 174 participants with knee osteoarthritis. Coronal magnetic resonance images were acquired at baseline and 26.6 ± 5.4 months later. The subchondral bone surface area of the weight-bearing tibiofemoral cartilages was segmented, with readers blinded to the order of acquisition. The size of the subchondral bone surface areas was computed after triangulation by proprietary software. The hip–knee–ankle angle showed a significant correlation with the tibial (r ² = 0.25, P < 0.0001) and femoral (r ² = 0.07, P < 0.001) ratio of medial-to-lateral subchondral bone surface area. In the tibia, the ratio was significantly different between varus (1.28:1), neutral (1.18:1), and valgus (1.13:1) knees (analysis of variance [ANOVA]; P < 0.00001). Similar observations were made in the weight-bearing femur (0.94:1 in neutral, 0.97.1 in varus, 0.91:1 in valgus knees; ANOVA P = 0.018). The annualized longitudinal increase in subchondral bone surface area was significant (P < 0.05) in the medial tibia (+0.13%), medial femur (+0.26%), and lateral tibia (+0.19%). In the medial femur, the change between baseline and follow-up was significantly different (ANOVA; P = 0.020) between neutral, varus, and valgus knees, with the increase in surface area being significantly greater (P = 0.019) in varus than in neutral knees. Tibiofemoral subchondral bone surface areas are shown to be functionally adapted to the medial-to-lateral load distribution. The longitudinal findings indicate that this adaptational process may continue to take place at advanced age.     

High tibial valgus osteotomy for medial gonarthrosis: a 10- to 21-year study

This retrospective study reviewed the long-term experience with high tibial osteotomy and determined which factors influence the results. Between 1980 and 1989, 120 closing wedge high tibial osteotomies for varus gonarthrosis were performed in 102 patients. Twenty-nine knees were excluded because the patients died (17 knees), were bedridden (7 knees), or lost to follow-up (5 knees). Thirty of the remaining 91 knees had a conversion to total knee replacement (TKR) after 11 years on average, leaving 61 knees with a high tibial osteotomy available for clinical and radiographic evaluation at an average follow-up of 15 years (range: 10-21 years). Of the 91 knees, excellent/good results were found in 49% and fair/poor in 51%. Anatomical femorotibial angle in the 61 knees at follow-up averaged 4.7 degrees +/- 5 degrees of valgus (range: 3 degrees varus to 23 degrees valgus). Alignment obtained at consolidation changed with varus recurrence at follow-up in 14% of 61 knees and did not correlate with the clinical results. Twelve (19%) knees showed a patella baja (Caton ratio <0.6) at follow-up, which correlated with patients immobilized postoperatively by a cylinder cast (P=.04). A valgus alignment at consolidation between 8 degrees and 15 degrees, good muscle strength, and male gender correlated with better results (P<.05). Survivorship analysis, considering an unsatisfactory result or revision to TKR as the endpoint, was 96% at 5 years, 88% at 7 years, 78% at 10 years, and 57% at 15 years. High tibial osteotomy provides symptomatic relief for approximately 10 years, but is unlikely to provide permanent relief.     

Revision total knee arthroplasty by impaction bone grafting

The presence of bone loss in a failed total knee arthroplasty can present a significant reconstructive challenge. Experience with the technique of using impacted morselized allograft with revision components having fixed stems is presented. Nineteen knees (21 patients) were reconstructed using impacted bone graft alone in 14 knees, bone graft plus methylmethacrylate in five knees (including one knee in which the replacement failed), and in three knees morselized bone graft was used in conjunction with structural bone allograft. Minimum followup ranged from 6 months to 62 months for the patients in the current series. These patients represent a relatively small, but growing portion of this surgeon's population of patients undergoing revision knee arthroplasty. Patients with large defects were selected for the study. Histologic specimens from the one failed knee arthroplasty revealed viable, incorporated bone graft. Excluding the replacement that failed, the average improvement in Knee Society combined knee and function scores was 87 points. The principles of revision and primary total joint arthroplasty are applied for achieving a stable implant. Specific to this technique, solid support of the implant-graft interface, graft-host bone interface, and the use of a tight, supportive stem is imperative. The author's experience provides additional support for the use of bone grafting techniques in patients with large bone defects who are undergoing revision total knee replacement.     

The effects of varus tibial alignment on proximal tibial surface strain in total knee arthroplasty

The aim of this study was to determine the effect of varus tibial alignment on proximal tibial strain in total knee arthroplasty. Fourteen paired fresh-frozen cadaver tibiae had photoelastic coating applied. The right tibiae were cut in neutral alignment, and the left tibiae were cut in 5° of varus. Components were cemented and loaded with 3× body weight, varying medial to lateral load. Surface microstrain was measured. There was a statistically increased hot spot of highly concentrated strain in the posteromedial quadrant of the proximal tibia in varus-cut bones (P<.05). In neutral alignment, the strain was nearly equal medial and lateral. The increased strain observed helps elucidate the mechanism of increased failure rates of a total knee arthroplasty inserted in varus alignment. Neutral alignment may have a protective effect.     

Ten- to 12-year followup of the Insall-Burstein I total knee prosthesis

The Insall-Burstein Posterior Stabilized knee prosthesis (Insall-Burstein I), developed at The Hospital for Special Surgery in 1978, has a metal-backed nonmodular tibial component. The polyethylene articular surface was directly molded. The purpose of the current study was to evaluate long-term wear with this design. The first 100 total knee arthroplasties (86 patients) performed by the senior author were followed prospectively. The average age of the patients at the time of surgery was 69.7 years (range, 45-89 years). The primary diagnoses were osteoarthritis in 77 knees (66 patients), inflammatory arthritis in 17 knees (14 patients), and posttraumatic arthritis in the remaining six knees (six patients). Thirty-eight knees (35 patients) had varus angulation, 14 knees (13 patients) had valgus angulation, and 48 knees (40 patients) had a 0 degrees to 10 degrees tibiofemoral angle preoperatively. All patients were evaluated at 10 to 12 years followup. Knee Society scores and radiographs were obtained. Thirty-six knees were in 30 patients who had died and two knees were in two patients who were infirm. Telephone evaluation only was available for eight knees (seven patients), leaving 54 knees (47 patients) for direct clinical and radiographic evaluation. No patients were lost to followup. The average Knee Society clinical score at latest followup was 91.6 points. The average function score was 69 points. One knee arthroplasty failed because of tibial loosening, one failed because of patella wear and fracture, two failed because of sepsis, and two failed because of nonspecific pain. There were seven patella fractures (7%) in the 100 knees. One of the fractures resulted in a total knee revision (noted above), two resulted in patellar component revision, and another resulted in patellar component removal. The remaining three patella fractures were discovered incidentally and were asymptomatic. There were no patellar dislocations. At long-term radiographic analysis, valgus alignment averaged 6 degrees (range, 0 degrees-11 degrees). Polyethylene wear averaged 0.40 mm. There was no catastrophic wear of tibial polyethylene. Thirty-two knees in 32 patients (65%) had radiolucencies in at least one zone; no lucency filled a zone, and none was wider than 2 mm. The absence of clinically significant tibial polyethylene wear at long-term followup is of particular interest. The performance of the molded, nonmodular polyethylene articulation is encouraging and needs to be analyzed critically against the more widely used machined, modular components used today.     

Cemented and ingrowth fixation of the Miller-Galante prosthesis. Clinical and roentgenographic comparison after three- to six-year follow-up studies

One hundred thirty-nine cemented and 132 cementless Miller-Galante total knee prostheses were followed between three and six years (average, 43-44 months). The fixation technique was based on patient age, bone quality, and ability to delay full-weight bearing. Clinical follow-up studies were possible on 116 cemented knees. Fifteen knees were lost because of death before the three-year follow-up study, and eight knees required component removal. One hundred twenty-three cementless knees were available for clinical follow-up studies; there were three deaths, and six failures required component removal. No cemented failure was due to fixation, and three cementless failures were due to lack of tibial ingrowth in two and pain of undetermined etiology in one. Preoperative knee scores were slightly significant with cemented knees averaging 48 points and cementless knees averaging 52 points. A similar significant difference was maintained at the final follow-up study. No significant differences were noted for pain, limp, or support scores. Average range of motion was similar in the two groups. Radiolucent lines about the femoral component were rare. Cementless tibial radiolucencies were partial in up to 20% of examined zones, and complete tibial tray radiolucency was seen in only three patients. No correlation between radiolucency and knee scores was seen.     

Is bone density in the distal femur affected by use of cement and by femoral component design in total knee arthroplasty?

The objective of this study was to evaluate changes in bone density in the distal femur 2 years after total knee arthroplasty with four different implant designs using cemented or cementless femoral components. Bone density was measured retrospectively from radiographs of 114 knees, using a densitometer. A decrease in bone density of up to 57% was identified in the distal femora with a cemented femoral component 2 years after surgery, compared with a decrease of up to 28% with a cementless, porous-coated component of the same design. The differences between the four implant designs in the changes in bone density in the anterior distal femur were significant at 2 years (P < 0.001). A possible cause of this result may be a difference in load transfer due to the different methods of fixation. The surgeon should expect decreased bone density in the distal femur at the time of revision surgery, especially with a cemented femoral component. Received for publication on June 5, 1998; accepted on Dec. 11, 1998     

Survivorship of AGC knee replacement in juvenile chronic arthritis: 13-year follow-up of 77 knees

This study analyzed the survivorship and results of 77 knee replacements in 52 patients with juvenile chronic arthritis using the nonconstrained Anatomically Graduated Components (AGC; Biomet, Warsaw, IN) prosthesis design. Patients were operated on between the years 1985 and 1995. The mean duration of the general disease was 24 years (range, 10-56 years), and the mean age of the patients at the time of surgery was 33 years (range, 16-64 years). Bone-grafts were installed into 15 knees, custom-made components were used in 5 knees, and cemented fixation in 4 knees. The patella was resurfaced in 23 knees. Clinical follow-up examinations were conducted 3 months, 1 year, 4 years, and 8 years postoperatively. An interview was arranged at the end of 1998, 3 to 13 years after surgery; 2 patients were not reached, and 2 died during the follow-up. Fifty-five of 73 (75%) knees were subjectively excellent, 18 (25%) were fair, and none was poor. Radiolucent lines of 1.0 to 1.5 mm were found under 14 tibial trays but not adjacent to femoral components. No deep infections were detected. One knee was revised 4 years after the implantation. The overall survival was 99% (95% confidence interval, 92-100) at 5 years. We consider these results excellent in this demanding patient material. The nonconstrained AGC prosthesis with cementless fixation proved to be feasible in knee replacement in patients with juvenile chronic arthritis.     

Osteolysis in a surface-cemented, primary, modular Freeman-Samuelson total knee replacement

We analysed at a mean follow-up of 7.25 years the clinical and radiological outcome of 117 patients (125 knees) who had undergone a primary, cemented, modular Freeman-Samuelson total knee replacement. While the tibial and femoral components were cemented, the patellar component was uncemented. A surface-cementing technique was used to secure the tibial components. A total of 82 knees was available for radiological assessment. Radiolucent lines were seen in 41 knees (50%) and osteolytic lesions were seen in 13 knees (16%). Asymptomatic, rotational loosening of the patellar implant was seen in four patients and osteolysis was more common in patients with a patellar resurfacing. Functional outcome scores were available for 41 patients (41 knees, 35%) and the mean Western Ontario McMasters Universities score was 77.5 (sd 19.5) and the cumulative survival was 93.4% at ten years with revision for aseptic loosening as an endpoint. Increased polyethylene wear from modular components, a rotationally-loose patella, and the surface-cementing technique may have contributed to the high rate of osteolysis seen in our study.     

Isolated Polyethylene Insert Exchange for Flexion Instability After Primary Total Knee Arthroplasty Demonstrated Excellent Results in Properly Selected Patients

BackgroundHistorically, isolated polyethylene exchange (IPE) for flexion instability after total knee arthroplasty (TKA) has demonstrated generally poor and unpredictable results. The purpose of this study is to evaluate the results of a single surgeon’s strict indications and protocol for IPE for flexion instability after primary TKA.MethodsBetween 2009 and 2016, 418 revision TKAs were performed by the senior author. Patients were considered for IPE if they demonstrated excellent radiographic alignment and component positioning preoperatively. Intraoperatively, if component rotation, sizing, and fixation were all excellent and the flexion and extension gaps could be balanced, then IPE was performed.We retrospectively reviewed 31 knees in 30 patients who were treated with IPE specifically for flexion instability after primary TKA. The mean follow-up was 41 months (range, 24-85 months). Nineteen knees were cruciate-retaining TKAs revised to a more constrained “deep-dish” ultracongruent insert, and 12 posterior-stabilized TKAs were revised to thicker posterior-stabilized insert.ResultsAt a mean follow-up of 41 months, only 2 of 31 knees (6.5%) required subsequent component revision surgery for recurrent instability. Knee Society pain scores improved from 70 preoperatively to 86 postoperatively (P < .0001), and function scores improved from 39 points preoperatively to 44 points postoperatively (P = .015).ConclusionIPE for flexion instability in carefully selected patients was successful in over 90% of patients for a mean follow-up of 41 months. Pain and function scores significantly improved. Longer-term follow-up is necessary to determine whether these results are durable over time.     

Tibial post failures in a condylar posterior cruciate substituting total knee arthroplasty

In posterior-stabilized total knee arthroplasties, a femoral cam and polyethylene tibial post are commonly used to restore posterior stability after sacrifice of the posterior cruciate ligament. This article reports a high incidence of early tibial post failures in one design of prosthesis and examines the variables that may have contributed to such. Five hundred sixty-four consecutive posterior-stabilized total knees were implanted in 512 patients, using a total knee prosthesis with a polyethylene tibial post and femoral cam. Clinical and radiographic outcomes were measured at a mean follow-up of 40 months after surgery (range, 24-83 months). At follow-up, 70 knees in 62 patients (12%) had undergone revision surgery because of symptoms related to catastrophic failure of the tibial post.     

Clinical and radiographic results of the total condylar III and constrained condylar total knee arthroplasty

The Total Condylar III (Johnson and Johnson, Braintree, MA) and Constrained Condylar (Zimmer, Warsaw, IN) knee prostheses are nonlinked, semi-constrained prosthetic alternatives to rigid or rotating hinge prostheses for use in complex knee reconstructions. Forty-six Total Condylar III or Constrained Condylar prostheses were implanted with cement in 36 patients and followed for a mean of 5 years (range, 2–9 years). There were 25 primary total knee arthroplasties and 21 revision total knee arthroplasties. The knees were evaluated using The Hospital for Special Surgery 100-point knee rating system. Overall, 40 knees (87%) had a good or excellent clinical result, 2 knees (4%) had a fair result, and 4 knees (9%) had a poor result. There was one revision for loosening of a cemented, nonmodular Constrained Condylar prosthesis, and one knee had a debridement for a late, metastatic infection, but the components were retained. There were no mechanical failures in those knees that were primary arthroplasties, but two mechanical failures occurred in those knees that were revision arthroplasties. Radiographic review showed one asymptomatic loosening of a Constrained Condylar tibial component with an uncemented press-fit stem, and only 8 knees had scattered nonprogressive tibial bone—cement radiolucent lines. The Total Condylar III and Constrained Condylar semiconstrained prostheses are successful when used in complex knee reconstructions.     

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.