Patellofemoral arthroplasty has been utilized as a treatment for isolated patellofemoral arthritis for more than 30 years. However, the use of this procedure remains controversial, as many surgeons prefer to use total knee arthroplasty, even for isolated patellofemoral arthritis. While historically, the results with this procedure have been inconsistent, recent developments in prosthesis design and surgical indications have improved the outcomes of patellofemoral arthroplasty. Potential advantages of patellofemoral arthroplasty include a less invasive approach, less bone resection, less tissue destruction, shorter operative time, less blood loss, shorter rehabilitation, and more normal knee kinematics. However, proper indications and surgical technique are crucial in order to obtain optimal results. Some future modifications have the potential to further improve the outcomes of the procedure, although additional investigations are needed to further explore some of these aspects. This report will describe current knowledge regarding the indications and contraindications for patellofemoral arthroplasty, present the results and complications of this procedure, discuss alternative treatments for patellofemoral disease, and explore future directions for arthroplasty of the patellofemoral compartment.

BACKGROUND Several studies have described equivalent performance on radiostereometric analysis at two years for metal-backed compared with all-polyethylene stemmed tibial implants. The purpose of this study was to determine the ten-year survivorship results of these two designs from a large randomized controlled trial. METHODS Patients who were fifty years old or more, with no history of infection, and were undergoing primary total knee arthroplasty were randomized at the time of surgery to receive either an all-polyethylene or a metal-backed tibial component. Patients were assessed preoperatively and at one, three, five, eight, and ten years postoperatively. All assessments included a clinical history, a physical examination, and a radiographic evaluation. A total of 510 consecutive patients (566 knees) were recruited from August 1993 to January 1997. The mean age of the patients at the time of the index arthroplasty was 69.3 years, and 299 (59%) were women. The primary diagnosis was osteoarthritis for 458 knees (80.9%) and rheumatoid arthritis for 108 knees (19.1%). RESULTS Two hundred and ninety-three patients returned for the ten-year follow-up evaluation. A total of twenty-eight knees had been revised. Ten-year survivorship, with revision for any reason (or the time at which patients were documented as requiring revision but were unfit for surgery) as the end point, was 94.5%(95% confidence interval, 90.4% to 96.8%) for the all-polyethylene design and 96%(95% confidence interval, 92.6% to 97.8%) for the metal-backed design. Ten-year survivorship, with aseptic failure as the end point, was 97%(95% confidence interval, 93.3% to 98.7%) for the all-polyethylene design and 96.8%(95% confidence interval, 93.6% to 98.4%) for the metal-backed design. On the basis of the numbers available at ten years, there was no significant difference in survivorship between the two designs (p > 0.05). CONCLUSIONS The long-term results demonstrate excellent survivorship, with revision as the end point, for both the metal-backed and the all-polyethylene tibial component designs with no differences noted between the two.

We describe a cohort of patients with a high rate of mid-term failure following Kinemax Plus total knee replacement inserted between 1998 and 2001. This implant has been recorded as having a survival rate of 96% at ten years. However, in our series the survival rate was 75% at nine years. This was also significantly lower than that of subsequent consecutive series of PFC Sigma knee replacements performed by the same surgeon. No differences were found in the clinical and radiological parameters between the two groups. At revision the most striking finding was polyethylene wear. An independent analysis of the polyethylene components was therefore undertaken. Scanning electron microscopy revealed type 2 fusion defects in the ultra-high molecular weight polyethylene (UHMWPE), which indicated incomplete boundary fusion. Other abnormalities consistent with weak UHMWPE particle interface strength were present in both the explanted inserts and in unused inserts from the same period. We consider that these type 2 fusion defects are the cause of the early failure of the Kinemax implants. This may represent a manufacturing defect resulting in a form of programmed polyethylene failure.

The St. Leger total knee replacement (Zynergy Orthopaedics Ltd, Rotherham, UK) was developed as a cheaper alternative to similar implants of its time. Between October 1993 and June 1999, 144 St. Leger total knee replacements were implanted into 114 patients. Seventy-three patients (99 knees) were recalled for assessment (mean follow-up of 10.2 years). Eighteen patients had had their prostheses revised, 11 had died and 12 were lost to follow-up. Functional Score showed 90% poor results and the Objective Knee Score showed 31% poor results. Radiological assessment identified 12 arthroplasties that had failed and 58 that required close follow. Kaplan-Meier cumulative survivorship was 87% at 10 years. The St. Leger knee replacement did not perform as well as others of the same generation and was not worth the initial financial savings.

As part of the government's initiative to reduce waiting times for major joint surgery in Wales, the Cardiff and Vale NHS Trust sent 224 patients (258 knees) to the NHS Treatment Centre in Weston-Super-Mare for total knee replacement. The Kinemax total knee replacement system was used in all cases. The cumulative survival rate at three years was 79.2%(95% confidence interval (CI) 69.2 to 86.8) using re-operation for any cause as an endpoint and 85.3%(95% CI 75.9 to 91.8) using aseptic revision as an endpoint. This is significantly worse than that recorded in the published literature. These poor results have resulted in a significant impact on our service.

In a prospective study, 194 knees undergoing total knee arthroplasty (110 knees with alumina ceramic prostheses; 84 knees with Co-Cr alloy prostheses) were clinically and radiologically evaluated. Average follow-up period was 66 months (36-124 months). Average age at the time of surgery was 66 years. In the ceramic prostheses, two revision surgeries were performed because of breakage of the tibial tray and late infection, whereas two revisions of the Co-Cr alloy prostheses were carried out due to loosening and late infection. In the other patients, there were no significant differences in clinical parameters (HSS knee score and range of motion) between the two prostheses. In radiological evaluation, we could not find any radiolucent lines around the femoral ceramic component while radiolucency was present in three knees (3.6%) around the Co-Cr femoral component. Beneath the tibial tray, three knees (2.7%) showed a radiolucent line around the former prosthesis while eight knees (9.5%) demonstrated a radiolucent line around the latter prosthesis. Chi-square tests showed a significant difference in the occurrence of radiolucent line around both of the femoral and tibial prosthesis. This study demonstrated that clinical results of the alumina ceramic PCL retaining total knee prosthesis are comparable to the standard Co-Cr alloy PCL retaining total knee prosthesis. Although we could not draw any conclusions regarding the superiority of the ceramic prosthesis with respect to UHMWPE wear and long-term survivorship, this report encouraged a long-term follow-up study on ceramic prostheses.

Revision total knee arthroplasty using a second generation modular rotating hinge design was done on thirty two knees in 30 patients over an 8-year period. Twenty-nine knees in 29 patients were followed up for 4.5-11 years (mean, 58 months). Four prostheses failed and two patients had died and one patient was lost to followup. Indications for revision were recurrent sepsis (five knees), component failure (four knees), ligamentous instability (two knees), aseptic loosening (10 knees), fracture (six knees), and gross bone loss (five knees). Early results have demonstrated improvement in both the Knee Society knee and function Scores and range of movement. The Knee Society knee score improved from 26 preoperatively to 68 postoperatively. The function score improved from 27 preoperatively to 75 postoperatively. One patient had evidence of aseptic loosening on radiographs, and the patellofemoral complication rate was low at 6%. This short-term clinical and radiographic review has demonstrated encouraging results in the use of a custom-made second generation rotating hinge component when used in revision knee surgery.

Porous tantalum represents an alternative metal for primary and revision total knee arthroplasty (TKA) with several unique properties. Tantalum is a transition metal, which in its bulk form has shown excellent biocompatibility and is safe to use in vivo as evidenced by its current application in pacemaker electrodes, cranioplasty plates, and as radiopaque markers. Current designs for orthopedic implants maintain a high volumetric porosity (70%-80%), low modulus of elasticity (3 MPa), and high frictional characteristics, making this metal conducive to biologic fixation. The low modulus of elasticity of such components allows for more physiologic load transfer and relative preservation of bone stock. Its more bioactive nature and ingrowth properties have led to its use in primary as well as revision knee components with good early clinical results reported. In revision arthroplasty, it has been used as a structural bone graft substitute. Formation of a bone-like apatite coating in vivo affords strong fibrous ingrowth properties and allows for substantial soft-tissue attachment with the potential for use in cases such as mega-prostheses and patella salvage. Although porous tantalum is in its early stages of evolution, the initial clinical data and basic science studies support its use as an alternative to traditional orthopedic implant materials.

Ninety-seven patients with 99 total knee arthroplasties were operated on by a surgeon in the first 3 years of his surgical career. Complete survival data were available for all 99 knees. The cases were reviewed at a minimum of 10 years after their initial operation, but as 37 patients had died before reaching 10 years, the average follow-up was 8 years 8 months with a maximum of 12 years 4 months. Ninety-one patients had osteoarthritis, five had rheumatoid arthritis, and three had juvenile chronic arthritis. No patients were lost to follow-up. Four required revision. The 10-year survival rate, using revision for all causes as an end-point, was 94.96%. The survival rate for aseptic loosening was 97.04%. The survival rate for loose joints that had not been revised was 94.13%. Three of the four revisions occurred in the first 6 patients operated upon, suggesting there may be a learning curve for surgeons at this stage in their career.

We report the mid-term results of a new patellofemoral arthroplasty for established isolated patellofemoral arthritis. We have reviewed the experience of 109 consecutive patellofemoral resurfacing arthroplasties in 85 patients who were followed up for at least five years. The five-year survival rate, with revision as the endpoint, was 95.8%(95% confidence interval 91.8% to 99.8%). There were no cases of loosening of the prosthesis. At five years the median Bristol pain score improved from 15 of 40 points (interquartile range 5 to 20) pre-operatively, to 35 (interquartile range 20 to 40), the median Melbourne score from 10 of 30 points (interquartile range 6 to 15) to 25 (interquartile range 20 to 29), and the median Oxford score from 18 of 48 points (interquartile range 13 to 24) to 39 (interquartile range 24 to 45). Successful results, judged on a Bristol pain score of at least 20 at five years, occurred in 80%(66) of knees. The main complication was radiological progression of arthritis, which occurred in 25 patients (28%) and emphasises the importance of the careful selection of patients. These results give increased confidence in the use of patellofemoral arthroplasty.

Revision total knee arthroplasty using a second generation modular rotating hinge design was done on thirty two knees in 30 patients over an 8-year period. Twenty-nine knees in 29 patients were followed up for 4.5-11 years (mean, 58 months). Four prostheses failed and two patients had died and one patient was lost to followup. Indications for revision were recurrent sepsis (five knees), component failure (four knees), ligamentous instability (two knees), aseptic loosening (10 knees), fracture (six knees), and gross bone loss (five knees). Early results have demonstrated improvement in both the Knee Society knee and function Scores and range of movement. The Knee Society knee score improved from 26 preoperatively to 68 postoperatively. The function score improved from 27 preoperatively to 75 postoperatively. One patient had evidence of aseptic loosening on radiographs, and the patellofemoral complication rate was low at 6%. This short-term clinical and radiographic review has demonstrated encouraging results in the use of a custom-made second generation rotating hinge component when used in revision knee surgery.

In skeletally immature patients, resection of bone tumours and reconstruction of the lower limb often results in leg-length discrepancy. The Stanmore non-invasive extendible endoprosthesis, which uses electromagnetic induction, allows post-operative lengthening without anaesthesia. Between 2002 and 2009, 55 children with a mean age of 11.4 years (5 to 16) underwent reconstruction with this prosthesis; ten patients (18.2%) died of disseminated disease and one child underwent amputation due to infection. We reviewed 44 patients after a mean follow-up of 41.2 months (22 to 104). The mean Musculoskeletal Tumor Society score was 24.7 (8 to 30) and the Toronto Extremity Salvage score was 92.3%(55.2% to 99.0%). There was no local recurrence of tumour. Complications developed in 16 patients (29.1%) and ten (18.2%) underwent revision. The mean length gained per patient was 38.6 mm (3.5 to 161.5), requiring a mean of 11.3 extensions (1 to 40), and ten component exchanges were performed in nine patients (16.4%) after attaining the maximum lengthening capacity of the implant. There were 11 patients (20%) who were skeletally mature at follow-up, ten of whom had equal leg lengths and nine had a full range of movement of the hip and knee. This is the largest reported series using non-invasive extendible endoprostheses after excision of primary bone tumours in skeletally immature patients. The technique produces a good functional outcome, with prevention of limb-length discrepancy at skeletal maturity.

Purpose: We reviewed all tumours of the sternum referred to The London Bone and Soft Tissue Tumour Service between 1956 and 1997 inclusive.Patients and results: There were eight patients with this pathology, the male to female ratio was 3:1 and their mean age was 53 years. Of these patients, three are alive and disease free, one is alive with recurrence, and four have died, two of the consequences of the disease and two of unrelated causes. Surgery is the principal treatment of these tumours both for excision and subsequent reconstruction.Discussion: Extended disease-free survival is possible with correct diagnosis, complete excision at the first operation, appropriate skeletal reconstruction, adequate skin cover and appropriate postoperative support and follow-up.

Large osteoarthritic cysts can sometimes be difficult to distinguish from primary osseous and soft tissue tumours. We present such a case involving a cyst arising from the hip joint and eroding the acetabulum which presented as a soft tissue malignancy referred to a tertiary bone and soft tissue tumour centre. We discuss the diagnostic problems it may pose, and present a literature review of the subject.

We prospectively randomised 104 consecutive patients undergoing primary cemented total knee arthroplasty into two groups of 52 patients each, with one group to receive a standard suction drain (Redivac) and the other, an autologous transfusion drain (Bellovac). Randomisation was achieved using the software programme MINIM:, which was set to randomly allocate patients to either of the two groups based on their age, sex and body mass index (BMI). All procedures were performed under pneumatic tourniquet. Drains were released in the recovery room 20 min after surgery and removed 24 h following surgery. Blood collected in the standard suction drain (control group) was discarded, while blood collected in the autologous transfusion drains (study group) was transfused unwashed back to the patient within 6 h of collection. Thirteen patients (25%) in the study group had two or more units of homologous blood transfused in addition to the blood collected postoperatively and re-transfused (average: 438 ml). Twelve patients (23%) in the control group had two or more units of homologous blood transfused. No sepsis, transfusion reactions or coagulopathies were associated with the autologous blood transfused in the study group. The use of the autologous transfusion system (Bellovac) proved to be safe but failed to reduce the need for postoperative homologous blood transfusion following uncomplicated total knee arthroplasty.

Component angles of 198 Kinemax total knee replacements were measured from standard short leg radiographs. An ideal tibio-femoral angle of between 4 and 10 degrees of valgus was achieved in 64.6% of patients. After an average follow-up of 6.5 years (range 4.5 to 9.5), there was no significant difference between knees in acceptable and suboptimal alignment in terms of pre- and post-operative knee and function scores and prevalence of radiolucent lines. Varus placement of the tibial component was significantly more common by trainee surgeons (P<0.001).

We performed a functional analysis of massive knee replacements after extra-articular resection of primary bone tumors. Patients did not score as highly on the Musculoskeletal Tumour Society Score and Knee Society Score (P < or =.01) as patients who had undergone intra-articular resection. Lower scores were achieved for emotional acceptance (P < or =.01), functional restriction (P < or =.05), walking distance (P < or =.05), and managing stairs (P < or =.05). These patients had a significantly greater extension lag (P < or =.01) and greater fixed flexion (P < or =.05). This functional deficit is primarily due to a compromised extensor mechanism inherent in the type of surgical resection necessary to achieve adequate removal of the tumor.

To combat the high incidence of aseptic loosening for young patients and for patients with failed implants after resection for bone tumors, intramedullary cementless fixation of massive tumor implants was investigated. These implants consist of a hydroxyapatite coated titanium stem. To date, 47 of these prostheses have been inserted for the treatment of primary bone tumors. Radiographs indicate that the stems are osseointegrated. Radiolucent lines have not been seen between the implant and the bone. Bone remodeling changes have been observed. In several cases in which the implant was not seated properly on the transaction site, bone grew to the shoulder of the implant. Bone remodeling was particularly evident in stems that were coated over their entire surface. In these cases, the implant induced local bone resorption so that the bone around the midstream region became thinner, with resorption of cortical bone on the periosteal surface and maintenance of bone on the endosteal surface adjacent to the stem. This effect was attributed to stress shielding, and a three-dimensional finite element model using loading data obtained from a telemetry study indicated that, where the stem was bonded to the bone over the entire surface, stresses in the outer cortex became reduced. In the finite element model, reducing the region of hydroxyapatite coating to approximately 1/3 of the stem length reduced the extent of the low-stress area in the outer cortex. Subsequently, prostheses have been coated with hydroxyapatite over only approximately 1/3 of their stem. This method of fixing the massive endoprosthesis to the bone is thought to be successful in the short-term and offers an alternative to cemented fixation.

Although rarely required, extendable reconstruction devices for replacing the entire femur offer children with malignant bone tumors the opportunity of a nearly normal development by overcoming an expected leg length discrepancy. Femoral integrity can be restored, allowing most patients to walk without the use of aids. There are no data available to provide evidence regarding long term results and morbidity in such patients. Six patients (range 2-12 years of age), three with osteogenic osteosarcoma and three with Ewing's sarcoma, were treated between 1988 and 1996 with custom made Stanmore extendable prosthetic total femoral replacements. One patient died 12 months after surgery because of complications relating to pulmonary metastasis. The remaining five patients were observed between 2.7 and 8.9 years (average, 5 years). No tumor recurrence has been recorded and no amputation has been performed. All surviving patients underwent an average of 9.4 operative procedures (range, 4-16 procedures) including 6.4 extension procedures (range, 3-10 procedures), and one prosthetic revision (range, 0-3 procedures). Five revisions in two patients were necessary because of infection, loosening of the prosthesis, mismatch between femoral head and acetabulum, or full extension of the extending mechanism. The functional results were measured in accordance with the Musculoskeletal Tumor Society rating score, with an average result of 77.3%. Total femoral replacement in a growing individual achieves good functional results yet has various risks for an uncertain outcome. Careful selection of the patient and realistic appraisal of the long term prospects are essential for successful treatment.

BACKGROUND For some surgeons, rotating-platform total knee designs are an intellectually appealing option to use for total knee arthroplasty because of the contention that they can self-align and accommodate small mismatches in the rotational position of the tibial and femoral components. We carried out a randomized clinical trial to determine if a posterior-stabilized, rotating-platform knee design provided better maximum knee flexion, better function, or better durability at five years of follow-up when compared with a fixed-bearing design. METHODS This randomized clinical trial of 240 primary total knee arthroplasties involved a single type of distal femoral implant (posterior-stabilized) and three different types of tibial implant (all-polyethylene fixed-bearing, modular-metal-backed fixed-bearing, and rotating-platform). The three tibial implant groups were balanced dynamically with a computerized randomization process that accounted for patient age, sex, and body mass index; surgeon; and implant type. Patients returned for examination and radiographs at three months, one year, two years, and five years postoperatively. RESULTS Knee range of motion was not significantly different among the all-polyethylene, modular-metal-backed, and rotating-platform tibial component groups at two years (mean, 111°, 111°, and 110°, respectively) or five years (mean, 110°, 109°, and 109°, respectively). Function, as measured with Knee Society scores, was not significantly different among the all-polyethylene, modular-metal-backed, and rotating-platform groups at two years (mean, 90, 91, and 91 points, respectively) or five years (mean, 88, 89, and 88 points, respectively). Stair-climbing scores were not significantly different among the three groups at two years (mean, 39, 40, and 39 points, respectively) or five years (mean, 37, 40, and 36 points, respectively). There were four revisions: one in the all-polyethylene group (patellar fracture), two in the modular-metal-backed group (aseptic loosening), and one in the rotating-platform group (deep infection). CONCLUSIONS In this randomized clinical trial, the rotating-platform total knee design was reliable and durable but did not provide better maximum knee flexion, better function, or better durability at five years postoperatively when compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component.

BACKGROUND Total knee arthroplasty (TKA) is a common form of treatment to relieve pain and improve function in cases of rheumatoid arthritis (RA). Good clinical outcomes have been reported with a variety of TKA prostheses. The cementless Hi-Tech Knee II cruciate-retaining (CR)-type prosthesis, which has 6 fins at the anterior of the femoral component, posterior cruciate ligament (PCL) retention, flat-on-flat surface component geometry, all-polyethylene patella, strong initial fixation by the center screw of the tibial base plate, 10 layers of titanium alloy fiber mesh, and direct compression molded ultra high molecular weight polyethylene (UHMWPE), is appropriate for TKA in the Japanese knee.The present study was performed to evaluate the clinical results of primary TKA in RA using the cementless Hi-Tech Knee II CR-type prosthesis. MATERIALS AND METHODS We performed 32 consecutive primary TKAs using cementless Hi-Tech Knee II CR-type prosthesis in 31 RA patients. The average follow-up period was 8 years 3 months. Clinical evaluations were performed according to the American Knee Society (KS) system, knee score, function score, radiographic evaluation, and complications. RESULTS The mean postoperative maximum flexion angle was 115.6°, and the KS knee score and function score improved to 88 and 70 after surgery, respectively. Complications, such as infection, occurred in 1 patient and revision surgery was performed. There were no cases of loosening in this cohort, and prosthesis survival rate was 96.9% at 12 years postoperatively. CONCLUSION These results suggest that TKA using the cementless Hi-Tech Knee II CR-type prosthesis is a very effective form of treatment in RA patients at 5 to 12 years postoperatively. Further long-term follow-up studies are required to determine the ultimate utility of this type of prosthesis.

BACKGROUND Long-term results of Genesis I modular total knee system are not well known. METHODS We analyzed data from 345 patients with 393 primary total knee arthroplasties (TKA) using the Genesis I prosthesis. In all cases, the posterior cruciate ligament (PCL) was retained, and the patella was not resurfaced. The minimum follow-up was 10 (range 10-16) years. RESULTS Preoperative range of motion improved from 89° preoperatively to 105° at the time of the most recent follow-up (p < 0.001). Mean preoperative Knee Society pain and function scores increased from 29 and 25 points to 91 and 85 points, respectively (p < 0.001). Tibiofemoral angle shifted from 2.40° of varus before to 4.8° of valgus after the operation (p < 0.001). Early postoperative complications occurred in 34 knees (8.6%). Manipulation under general anesthesia was done in six knees (1.5%). Nonprogressive radiolucent lines were seen around the femoral component in 16 knees (4%) and at the tibial bone-cement interface in 101 knees (25%). However, in only five cases (1.3%) was there significant progression leading to implant loosening and revision surgery. Eight more revisions were performed due to infection (three knees), stiffness (three knees), excessive wear and fracture of polyethylene liner (one knee), and instability (one knee). The overall survivorship of knee replacement reached 96.7%. CONCLUSIONS In the long term (up to 16 years), PCL-retaining Genesis I total knee prosthesis is associated with good functional outcomes and low failure rates.

PURPOSE To compare mid-term outcomes of a high-flexion prosthesis with a conventional prosthesis. METHODS Records of 107 consecutive patients who underwent total knee arthroplasty (TKA) for primary osteoarthritis by a single surgeon were reviewed. 21 men and 36 women (mean age, 65 years) used a high-flexion prosthesis (NexGen CR-Flex Mobile, Zimmer), whereas 38 men and 12 women (mean age, 67 years) used a conventional prosthesis (Genesis II, Smith & Nephew) that preserves the posterior cruciate ligament, with mobile-bearing polyethylene inlay. The Knee Society knee and functional scores and the range of motion (especially maximum passive flexion) were assessed. Radiographs were evaluated to identify radiolucent lines at the bone cement interface, patella tracking, tibiofemoral alignment, and implant positioning. RESULTS The mean follow-up period was 68 (range, 51- 70) months. In terms of the mean Knee Society scores and range of motion, the difference between groups was not significant (p>0.05), but the improvement in both groups after TKA was significant (p<0.005). Respectively in the high-flexion and conventional TKA groups, 2 and one of the patients developed deep vein thrombosis and were treated with anticoagulants for 3 months. One and 5 of the patients had an unsatisfactory range of motion (<60º) in week 1, which was resolved with mobilisation under general anaesthesia in combination with a peridural catheter for analgesia. No patient developed implant-specific complications such as aseptic loosening (osteolysis, progressive radiolucent lines, implant deviation) or dislocation of the polyethylene insert. CONCLUSION The high-flexion prosthesis revealed no significant advantages over the conventional prosthesis in terms of the Knee Society scores and range of motion. Long-term studies are needed to determine whether the high-flexion implant is superior to the conventional implant in terms of polyethylene wear and aseptic loosening.

PURPOSE: In this prospective study, we determined whether corrective surgery for isolated rotational malalignment of femoral prosthesis components would benefit patients previously treated with total knee arthroplasty. The symptoms, amount of malrotation and type of constraint necessary for the revision prosthesis were investigated. METHODS: Seventy-two patients were screened with computed tomography; of these, 14 had isolated internal malrotation of the femoral component with no other malpositions and were included in the study. A complete exchange arthroplasty with the correction of the malrotated femoral component was performed within 3 years of primary arthroplasty. Mean follow-up was 57 months. RESULTS: At the time of revision, patients suffered either from instability in flexion with good range of motion (ROM)(flexion ≥90°) and pain on the lateral side of the distal femur and proximal tibia (n = 8) or from stiffness with pain on the medial side of the proximal tibial and poor ROM (flexion <90°)(n = 6). One patient showed no patellar maltracking, six patients, patellar tilt and six patients, patellar subluxation. Median internal rotation of the femoral component was 7.1° (4.1-10.0°). A condylar-type revision implant with a posterior-stabilized insert was used in all patients. The corrective surgery resulted in an increase in the mean Knee Society Score from 52/65 to 85/84 points and an improvement in the mean Hospital for Special Surgery knee score from 63 to 83 points. CONCLUSIONS: Correction of isolated internal malrotation of the femoral component ≥4° improves patient outcome.

PURPOSE Little is known about intra-operative difficulties and outcomes of TKA in ACL deficient knees. METHODS Fifty-seven osteoarthritic knees (mean age 70 years) with a history of ACL injury underwent posterior-stabilised TKA. Intra-operative findings and results were compared with a matched control group. RESULTS Difficult tibial exposure and bone loss were noted in the ACL-deficient group leading to one partial patellar tendon avulsion and one femoral condylar fracture. After three years, no infections or revisions occurred. No differences were noted in ROM, IKS knee score (95 ± 6 versus 93 ± 8, p = 0.1), IKS function score (83± 19 versus 84 ± 16, p = 0.7), or radiolucent line presence. CONCLUSIONS Total knee arthroplasty in ACL deficient knees is effective. Difficulty obtaining tibial exposure and posteromedial tibial bone defects should be anticipated. Outcomes are comparable to standard primary TKA.

INTRODUCTION The success of total knee arthroplasty is measured by pain relief, functional recovery, and implant survival duration. The aim of the present study was to evaluate the long-term clinical, functional and radiological results of the posterior cruciate ligament (PCL)-retaining fixed bearing EUROP implant. HYPOTHESIS The long-term results of EUROP implants are similar to those reported with comparable prostheses. PATIENTS AND METHODS We performed a prospective, monocentric study of a series of 121 cemented EUROP total knee arthroplasties, implanted between 1994 and 1996 in 117 patients mean age 73. A clinical and radiological evaluation was performed at 10 years of follow-up according to the International Knee Society (IKS) score. Twenty-three patients died, 14 were lost to follow-up, 43 underwent clinical and radiological evaluation and 37 were questioned by telephone. RESULTS The preoperative IKS knee score was 31 points (0-60) and increased to 88 points (30-98) at final follow-up, IKS function increased from 40 (0-90) to 80 points (25-100). Radiolucencies were observed in 56% of the condyles and 60% of tibial plates. Ninety-three percent of these radiolucent lines were less than 1mm wide. Three patients underwent revision TKA at 32 months, eight and 11 years respectively. Global implant survival was 99% at five years, 97.8% at 10 years and 95.8% at 12 years. DISCUSSION The clinical and radiological results of the cruciate-retaining fixed bearing EUROP total knee arthroplasties, with three cases of revision arthroplasty at 12 years of follow-up are satisfactory and comparable to similar implants.

We previously evaluated 119 consecutive total knee arthroplasties performed by a single surgeon in eighty-six patients with use of the cemented LCS (low contact stress) mobile-bearing, rotating-platform system and an all-polyethylene patellar component. The average age of the patients at the time of surgery was seventy years. The patients were contacted as part of their routine follow-up and were asked to participate in this study. The purpose of the present study was to report the updated results at a minimum follow-up of twenty years. Twenty patients (twenty-six knees) were living, and one was lost to follow-up. Three knees required a reoperation (two for periprosthetic fractures and one for infection). No component was revised as a part of the reoperations. No knee required revision since the fifteen-year follow-up evaluation. Osteolysis was present in six knees compared with only three knees at the time of the fifteen-year follow-up. One knee had radiographic signs of femoral component loosening, which was associated with osteolysis. It occurred after the fifteen-year follow-up study. The average range of motion was from 1 degrees of extension to 105 degrees of flexion. The average clinical and functional Knee Society scores were 43 and 49 points, respectively, at the preoperative evaluation and 89 and 67 points at the time of the final follow-up. We concluded that the cemented LCS rotating-platform knee performed well, with durable clinical and radiographic results at a minimum follow-up of twenty years. However, the prevalence of osteolysis continues to increase with a longer duration of follow-up in these patients.

A prospective study was performed to compare the clinical and radiological results of mobile- and fixed-bearing total knee arthroplasty with specific attention to rotational alignment and range of motion. Sixty-one knees were assigned to total knee arthroplasty with either the NexGen LPS Flex fixed-bearing or with the NexGen LPS Flex mobile-bearing prosthesis. Postoperatively, knees were compared with regard to range of motion, clinical score, and radiographic findings. Rotational alignment of the femoral and tibial components was evaluated by computed tomography. The median follow-up period was 5.9 years (range 2.1-8.8 years). Median postoperative Knee Society scores were 99 points (68-100) for the fixed-bearing group and 100 points (66-100) for the mobile-bearing group (n.s.). The median postoperative flexion angles of 120° (90°-150°) for the fixed-bearing group and 125° (90°-145°) for the mobile-bearing group were not significantly different from each other (n.s.). No knee required revision surgery due to wear of polyethylene or loosening of the component in either group. Computed tomography showed that 11 knees had rotational mismatches of more than 10° between the femoral and tibial components, but no significant difference was found in the postoperative extension and flexion angles or in the clinical score between the two treatment groups. Using the identical design for both fixed- and mobile-bearing prostheses, this prospective, randomized study did not show any clinical advantages of the mobile-bearing knee. Analysis of rotational alignment by CT scan did not reveal a particular advantage of the self-aligning mechanism of mobile-bearing implants.

We studied 75 primary total knee arthroplasties (TKAs) performed using a single-radius, high-flex posterior-stabilized insert design with a minimum 5-year follow-up to document its implant specific complications and clinical results. Nonprogressive osteolysis was observed at zone 4 of the femoral component in 6 knees (8%) and at zone 1 of the tibial component in 6 knees (8%). However, no complications associated with high flexion designs, such as early aseptic loosening, were observed.Preoperatively, mean Knee Society Knee Score and Knee Society Function Score were 55.1 and 45.5, respectively (range, 10-83 and 20-80, respectively). At last follow-up, mean Knee Society Knee Score and Knee Society Function Score improved to 94.9 and 85.9, respectively (range, 70-100 [P<.0001] and 45-100 [P<.0001], respectively). Mean maximal flexion was 122.1 degrees (range, 90 degrees -140 degrees ) and mean range of motion (ROM) was 110.3 degrees (range, 80 degrees -135 degrees ) preoperatively, and these values improved to 128.9 degrees (range, 110 degrees -150 degrees [P<.0001]) and 127.8 degrees (range, 110 degrees -150 degrees [P<.0001]), respectively, at last follow-up. Preoperative ROM was found to be the only factor significantly correlated with postoperative ROM at last follow-up by univariate (P=.0020) and multivariate analysis (P<.0067). Accordingly, clinical results were comparable to previous reports of high-flex implants without implant-specific complications.