Survival and clinical function of cemented and uncemented prostheses in total knee replacement

Management of knee injuries: consensus-based indications from a large community of orthopaedic surgeons

PURPOSE

To describe preferences and to quantify the amount of agreement among orthopaedic surgeons regarding treatment options for four clinical scenarios of knee pathologies.

METHODS

A web-based survey was developed to investigate the attitudes of members of an international association of surgeons specialised in sports traumatology and knee surgery European Society of Sports Traumatology, Knee Surgery and Arthroscopy.

RESULTS

The response rate was 40 % (412 questionnaires). An inter-rater agreement score (the Normalised Chi-square based Agreement Nomogram, NX2A) was calculated for each question. For scenario 1, 56-year-old male, degenerative medial compartment on both the femoral and tibial side, the surgical approach was preferred to the conservative approach (p < 0.001). Biological procedures were not considered appropriate, and in this respect, the respondents achieved a moderate degree of agreement (NX2A = 0.68). For scenario 2, 35-year-old male, early knee medial arthritis, the surgical treatment was preferred to conservative treatment (p < 0.001). The traditional closed-wedge tibial osteotomy was not regarded as an appropriate treatment with an excellent degree of agreement among surgeons (NX2A = 0.76). For scenario 3, 46-year-old male, ACL lesion, there was an almost disagreement, as respondents showed no preference between a surgical and conservative approach (NX2A = 0.005). Among surgical treatments, an almost perfect agreement with regard to the appropriateness of arthroscopic single-bundle ACL reconstruction with a semitendinosus/gracilis graft was reached by the surgeons (NX2A = 0.8). For scenario 4, 69-year-old male, diffuse knee arthritis (all the compartments), an almost perfect agreement in favour of a total knee prosthesis was obtained for the management of this scenario (NX2A = 0.85).

CONCLUSIONS

Web-based survey can help orthopaedic surgeons discuss and propose indications for clinical practice in the management of some of the most common joint diseases.

LEVEL OF EVIDENCE

Cross-sectional survey, Level V.

Hybrid micro/nano-topography of a TiO2 nanotube-coated commercial zirconia femoral knee implant promotes bone cell adhesion in vitro

Various approaches have been studied to engineer the implant surface to enhance bone in-growth properties, particularly using micro- and nano-topography. In this study, the behavior of osteoblast (bone) cells was analyzed in response to a titanium oxide (TiO2) nanotube-coated commercial zirconia femoral knee implant consisting of a combined surface structure of a micro-roughened surface with the nanotube coating. The osteoblast cells demonstrated high degrees of adhesion and integration into the surface of the nanotube-coated implant material, indicating preferential cell behavior on this surface when compared to the bare implant. The results of this brief study provide sufficient evidence to encourage future studies. The development of such hierarchical micro- and nano-topographical features, as demonstrated in this work, can provide insightful designs for advanced bone-inducing material coatings on ceramic orthopedic implant surfaces.

Cruciate-retaining vs posterior-substituting inserts in total knee arthroplasty: functional outcome comparison

Despite clinical success, it is unclear which one, posterior-substituting (PS) or cruciate-retaining (CR) insert, has superior functional outcomes or longevity. We compared the collected results from 2 institutional review board-approved, multicenter, prospective observational studies following CR (412) and PS inserts (328). Participants were evaluated preoperatively, at 6 weeks, at 3 months, and at 1 and 2 years regarding pain, motion, function (Knee Society Score, Krackow Activity Score, Short Form-36), and procedure variables such as anesthesia and preoperative/perioperative/postoperative complications. Implant longevity was recorded at the 2-year follow-up. Improvement was observed within each group; however, there was no difference between groups in terms of pain, motion, or function at any end point. Two-year survival rate was higher than 95%. A higher incidence of wound hematoma was observed in the PS group. Both inserts can be used expecting satisfactory outcomes and high survival rates at 2 years.

[Arthroplasty registers as post-marketing surveillance systems: the Catalan Arthroplasty Register]

OBJECTIVE

The aim is to present the functioning and results of the Catalan Arthroplasty Registry (RACat).

MATERIAL AND METHOD

The RACat arose by the initiative of the Catalan Society of Orthopaedic Surgery and Traumatology, the Catalan Health Service (CHS) and the Catalan Agency for Health Information Assessment and Quality. Publicly funded hospitals sent information through the Internet (CHS Applications website) on knee and hip arthroplasties: patient identification, hospital, joint (hip/knee), type (primary/revision), side of operation, date of surgery and prosthesis (manufacturer's name and reference number). The quality of the data is analysed regularly. We estimate the risk of replacement by the Kaplan-Meier method.

RESULTS

A total of 52 hospitals out of 62 send data to RACat, and information on 36,951 knee and 26,477 hip arthroplasties is available. Data quality improved between 2005 and 2010. In 2010 coverage exceeded 70%, with side of operation 97%, and prostheses identification of 80%. The risk of replacement at three years was 3.3% (95% CI:3.1-3.6) for knee, 2.9% (95% CI:2.5-3.3) for total hip, and 2.5% (95% CI:2.0-3.1) for partial hip.

DISCUSSION

Risk of replacement is higher than that observed in other registers, although data quality and its improvement over time should be taken into account.

CONCLUSIONS

The information available in the RACat will help to establish a standard that will enable hospitals to compare results.

Cementless fixation in total knee arthroplasty

There has been a recent increase in interest for non-cemented fixation in total knee arthroplasty (TKA), however the superiority of cement fixation is an ongoing debate.

Whereas the results based on Level III and IV evidence show similar survivorship rates between the two types of fixation, Level I and II evidence strongly support cemented fixation. United Kingdom, Australia, Sweden, and New Zealand registry data show lower failure rates and greater usage of cemented than non-cemented fixation. Case series studies have also indicated greater functional outcomes and lower revision rates among cemented TKAs. Non-cemented fixation involves more patellofemoral complications, including increased susceptibility to wear due to a thinner polyethylene bearing on the cementless metal-backed component. The combination of results from registry data, prospective randomised studies, and meta-analyses support the current superiority of cemented fixation in TKAs.

Cemented, cementless or hybrid fixation options in total knee arthroplasty for osteoarthritis and other non-traumatic diseases

BACKGROUND

It is not clear which fixation of total knee arthroplasty obtains the best clinical, functional and radiographic results in people with osteoarthritis and other non-traumatic diseases, such as rheumatoid arthritis.

OBJECTIVES

To assess the benefits and harms of cemented, cementless and hybrid knee prostheses fixation techniques in participants with primary osteoarthritis (osteoarthritis following trauma was not included) and other non-traumatic diseases, such as rheumatoid arthritis.

SEARCH METHODS

We searched CENTRAL (2011, issue 10), MEDLINE via PubMed, EMBASE, Current Controlled Trials, LILACS, The Cumulative Index to Nursing and Allied Health Literature, SPORTDiscus, Health Technology Assessment Database and the Database of Abstracts of Reviews of Effectiveness, all from implementation to October 2011, along with handsearches of high-yield journals and reference lists of articles. No language restrictions were applied.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating cemented, cementless and hybrid fixation. Participants included patients that were 18 years or older with osteoarthritis and other non-traumatic diseases who were undergoing primary total knee arthroplasty.

DATA COLLECTION AND ANALYSIS

Three authors independently selected the eligible trials, assessed the trial quality, risk of bias and extracted data. Researchers were contacted to obtain missing information.

MAIN RESULTS

Five RCTs and 297 participants were included in this review. Using meta-analysis on roentgen stereophotogrammetric analysis (RSA) we observed that cemented fixation of the tibial components demonstrated smaller displacement in relation to cementless fixation (with and without hydroxyapatite) after a follow-up of two years (maximum total point-motion, N = 167, two RCTs, mean difference (MD) = 0.52 mm, 95% confidence interval (CI) 0.31 to 0.74). However, the risk of future aseptic loosening with uncemented fixation was approximately half that of cemented fixation according to the arthroplasty instability classification (moderate quality as assessed by GRADE) inferred from RSA (N = 216, three RCTs, risk ratio (RR) = 0.47, 95% CI 0.24 to 0.92) with a 16% absolute risk difference between groups. The number needed to treat for an additional beneficial outcome (NNTB) to prevent future aseptic loosening was 7 (95% CI 5 to 44). There was a low risk of bias for RSA among the studies included. It was not possible to perform meta-analysis on patient-important outcomes, such as the survival rate of the implant (any change of a component), patient global assessments, functional measures, pain, health-related quality of life measures and adverse events. Almost all included studies recorded functional measures of Knee Society and Hospital for Special Surgery knee scores, but the authors of each study found no significant difference between the groups.

AUTHORS' CONCLUSIONS

There was a smaller displacement of the cemented tibial component in relation to the cementless fixation in studies with osteoarthritis and rheumatoid arthritis participants who underwent primary total knee prosthesis with a follow-up of two years; however, the cemented fixation presented a greater risk of future aseptic loosening than cementless fixation.

Long-term outcome in an uncemented, hydroxyapatite-coated total knee replacement

A consecutive series of patients with a hydroxyapatite-coated uncemented total knee replacement (TKR) performed by a single surgeon between 1992 and 1995 was analysed. All patients were invited for clinical review and radiological assessment. Revision for aseptic loosening was the primary outcome. Assessment was based on the Knee Society clinical score (KSS) and an independent radiological analysis. Of 471 TKRs performed in 356 patients, 432 TKRs in 325 patients were followed for a mean of 16.4 years (15 to 18). The 39 TKRs in 31 patients lost to follow-up had a mean KSS of 176 (148 to 198) at a mean of ten years. There were revisions in 26 TKRs (5.5%), of which 11 (2.3%) were for aseptic loosening. Other further surgery was carried out on 49 TKRs (10.4%) including patellar resurfacing in 20, arthrolysis in 19, manipulation under anaesthetic in nine and extensor mechanism reconstruction in one.

Survivorship at up to 18 years without aseptic loosening was 96% (95% confidence interval 91.9 to 98.1), at which point the mean KSS was 176 (134 to 200). Of 110 knees that underwent radiological evaluation, osteolysis was observed in five (4.5%), one of which was revised.

These data indicate that uncemented hydroxyapatite-coated TKR can achieve favourable long-term survivorship, at least as good as that of cemented designs.

Predisposing factors which are relevant for the clinical outcome after revision total knee arthroplasty

PURPOSE

The objective of this study was to investigate the outcome of revision total knee arthroplasty (TKA) in relation to the cause of index failure, the characteristics of the index procedure, and the elapsed time between index TKA and revision.

METHODS

A retrospective review based on a prospective database was performed on 146 consecutive revision TKA's. Variables tested were the cause of index failure; the elapsed time between the index and revision procedure; patient age at time of revision; partial or total revision of the implants; the performance of a tibial tubercle osteotomy; the presence of radiolucent lines; postoperative patellar tracking; and coronal plane alignment. Outcomes were measured with the Knee Society Knee Score (KS), Function Score (FS), and X-ray evaluation.

RESULTS

Mean KS improved from 27.6 (SD 21.6) to 71.5 (SD 24.2) after revision (P < 0.0001), mean FS from 27.5 (SD 22.7) to 53.3 (SD27.7), P < 0.0001. Overall survival rate was 90% at 5 years and 85% at 10 and 14 years. The cause of index failure had no significant influence on any of the outcome parameters. Significantly, better outcomes were noted for partial revisions and for revisions in older patients. Early revisions (<2 years) were mostly performed for infection and instability, whereas late revisions (>2 years) were mostly performed for polyethylene wear and loosening. The survival rate for late revisions was significantly better than for early revisions (P = 0.002).

CONCLUSION

Revision TKA leads to a significant reduction in symptoms and improvement in function. The worst results can be expected for early revisions in young patients. Revision TKA is a demanding procedure with variable results and should therefore be performed by experienced surgeons.

LEVEL OF EVIDENCE

Therapeutic study-Level IV.

Tibial component fixation with a peri-apatite coating: evaluation by radiostereometric analysis in a canine total knee arthroplasty model

Cementless fixation for the tibial component in total knee arthroplasty (TKA) remains problematic. Peri-Apatite (PA), a solution-deposited hydroxyapatite, is under investigation as an option for improving the fixation of cementless tibial components. In this study, radiostereometric analysis was used to document implant migration in 48 dogs that underwent TKA with cementless, PA-coated, or cemented tibial components. Migration at 12 weeks was similar in the 2 groups. At 12 months, there was greater migration in the PA-coated group, but the difference between the 2 groups was below the threshold considered clinically significant. In this canine TKA model, cementless fixation with PA performed less well than did cemented fixation, but not to a degree that would make a clinical difference in the short term.

Increased operating room time in patients with obesity during primary total knee arthroplasty: conflicts for scheduling

Obesity is associated with increased complications related to total knee arthroplasty (TKA), but the relationship between body mass index (BMI) and operating room time during TKA is unknown. A total of 454 unilateral primary TKAs (2005-2009) were reviewed and categorized by BMI (normal weight, 18.5-25 kg/m(2); overweight, 25-30 kg/m(2); obese class I, 30-<35 kg/m(2); class II, 35-40 kg/m(2); class III, >40 kg/m(2)). Intraoperative time measurements (total room time, anesthesia induction time, tourniquet time, closing time, surgery time) were compared across the BMI groups. Comparing normal weight to obese class III, time differences were significant in total room time (24 minutes, P < .01), surgery time (16 minutes, P < .01), tourniquet time (7.5 minutes, P < .01), and closure time (8 minutes, P < .01). Armed with this information, BMI can be used to better allocate operating room time for TKA.

Differences in proliferation, differentiation, and cytokine production by bone cells seeded on titanium-nitride and cobalt-chromium-molybdenum surfaces

Titanium-nitride coating is used to improve cobalt-chromium-molybdenum implant survival in total knee arthroplasty, but its effect on osteoconduction is unknown. Chromium and cobalt ions negatively affect the growth and metabolism of cultured osteoblasts while enhancing osteoclastogenic cytokine production. Therefore, it was hypothesized that a titanium-nitride surface would enhance osteoblast proliferation and/or differentiation and reduce osteoclastogenic cytokine production compared with a cobalt-chromium-molybdenum surface. MC3T3-E1 osteoblasts showed increased proliferation and decreased differentiation on titanium-nitride, while cytokine interleukin-6 production was higher on porous cobalt-chromium-molybdenum (p < 0.05), though interleukin-1β was occasionally detected on both surfaces. These findings suggest improved osteoconduction on titanium-nitride compared with cobalt-chromium-molybdenum surface.

Full and surface tibial cementation in total knee arthroplasty: a biomechanical investigation of stress distribution and remodeling in the tibia

BACKGROUND

Aseptic tibial component loosening remains a major cause of total knee arthroplasty failure. The cementation technique used to achieve fixation may play a major role in loosening. Despite this, the optimum technique remains unanswered. This study aims to investigate stress and strain distributions in the proximal tibia for full cementation and surface cementation of the Genesis II tibial component.

METHODS

Principal cortical bone strains were measured experimentally in intact, surface cemented and fully cemented synthetic tibiae using strain gauges. Both axial and 15° flexion loading were considered. Finite element models were used to assess both cortical and cancellous bone stresses and strains. Using a bone remodeling algorithm potential sites of bone formation and resorption were identified post-implantation.

FINDINGS

Principal cortical bone strain results demonstrate strong correlations between the experimental and finite element analyses (R(2)≥0.81, RMSE(%)≤17.5%). Higher cortical strains are measured for surface cementation, as full cementation creates a stiffer proximal tibial structure. Simulations reveal that both cementation techniques result in lower cancellous stresses under the baseplate compared to the intact tibia, with greater reductions being computed for full cementation. The surface cementation model displays the closest cancellous stress distribution to the intact model. In addition, bone remodeling simulations predict more extensive bone resorption under the baseplate for full cementation (43%) than for surface cementation (29%).

INTERPRETATION

Full cementation results in greater stress reduction under the tibial baseplate than surface cementation, suggesting that surface cementation will result in less proximal bone resorption, thus reducing the possibility of aseptic loosening.

Functional Outcomes in High-function-demand patients after total knee arthroplasty

Total knee arthroplasty is a safe last-resort treatment for osteoarthritis that has excellent results in low-function-demand elderly patients. Current implants offer the same results in high-function-demand patients. However, supportive data do not exist.One-year Krackow Activity Scores (KAS) of 552 patients from 2 prospective studies were used to retrospectively determine low- and high-function-demand populations. Low function demand was defined as a KAS between 1 and 9 points, and high function demand was defined as a KAS between 10 and 18 points. Patients were assessed preoperatively and at 6 weeks, 3 months, and 1 and 2 years postoperatively per the Knee Society Score-function domain, KAS, SF-36, range of motion, and pain. Comparability between groups was tested for demographics and comorbidities.Both groups showed significant improvement in function, range of motion, and pain 2 years postoperatively. High-function-demand patients had comparable improvement in function compared with low-function-demand patients. Excellent function can be achieved in high-function-demand patients.

A prospective randomized clinical trial comparing tibial baseplate fixation with or without screws in total knee arthroplasty: a radiographic evaluation

In a randomized prospective study, we compared the use of tibial screws with screwless tibial baseplate fixation in uncemented total knee arthroplasty and report the results of 154 prostheses at a mean follow-up of 5 years. Patients were mobilized within 24 hours and continued with partial weight-bearing for up to 6 weeks postoperatively. There were no significant differences in radiologic results and revision rates. Radiographic outcomes do not seem to be influenced by the use of screws in tibial baseplate fixation of this prosthesis. The prosthesis studied has a large tibial keel and 4 adjunctive pegs that seem to provide adequate stability and allow bony ingrowth to take place. Longer follow-up will determine whether in this implant design, the use of tibial screws for cementless tibial baseplate fixation can be justified.

[Long-term results in total knee arthroplasty. A meta-analysis of revision rates and functional outcome]

BACKGROUND

Total knee arthroplasty (TKA) is one of the most common procedures in orthopedic surgery and clinical success can be characterized by the revision rate and improvement of function. To quantify both characteristics two independent meta-analyses have been performed.

MATERIALS AND METHODS

A search in Medline provided a total of 96 studies on revision rates and 63 studies with functional results with a minimum follow-up of 5 years.

RESULTS

A total of 911 revisions among 20,873 TKAs were identified corresponding to a meta-revision rate of 4.4% after a mean follow-up of 10.7 years. Most common causes for revision were aseptic loosening (31%), infection (23%), polyethylene wear (16%) and patellar problems (14%). Revision rates were higher in younger patients (7.0% <60 years at time of operation, 5.0% between 60 to 70 years and 2.2% >70 years), after cementless TKA (8.3% cementless versus 3.6% cemented) and in studies with a higher rate of patients with rheumatoid arthritis. The second meta-analysis revealed a meta-improvement based on the Knee Society Knee Score of 51.3%, for the Knee Society Function Score of 30.6%, for the Hospital for Special Surgery Score of 36.1% and for the New Jersey Orthopedic Hospital Knee Evaluation System of 33.6%.

CONCLUSION

TKA is a successful treatment for osteoarthritis of the knee with an expectable revision rate of less than 5% within 10 years and a long-lasting functional improvement of more than 30% in any assessment score.

Simultaneous cemented and cementless total knee replacement in the same patients: a prospective comparison of long-term outcomes using an identical design of NexGen prosthesis

The purpose of this prospective, randomised study was to evaluate the clinical and radiological results comparing the identical cemented or cementless NexGen total knee prostheses implanted bilaterally in the same patient. Sequential simultaneous bilateral total knee replacements were performed in 50 patients (100 knees). There were 39 women and 11 men with a mean age of 58.4 years (51 to 67) who received a cemented prosthesis in one knee and a cementless prosthesis in the other. The mean follow-up was 13.6 years (13 to 14). At final review, the mean Knee Society scores (96.2 (82 to 100) versus 97.7 (90 to 100)), the mean Western Ontario and McMaster Universities osteoarthritis index (34.5 (4 to 59) versus 35.6 (5 to 51)), the mean ranges of knee movement (124° (100° to 140°) versus 128° (110° to 140°)), mean patient satisfaction (8.1 (SD 1.9) versus 8.3 (SD 1.7)), and radiological results were similar in both groups. The rate of survival of the femoral components was 100% in both groups at 14 years. The rate of survival of the cemented tibial component was 100% and 98% in the cementless tibial component. No osteolysis was identified in either group. Our data have shown no advantage of cementless over cemented components in total knee replacement.

The Genesis II in primary total knee replacement: a systematic literature review of clinical outcomes

Since its introduction in 1996, the Genesis II Total Knee System has produced good clinical results in patients undergoing primary total knee replacement. A systematic review of the literature-the first of its kind for this device-was undertaken to collect data on the Genesis II in order to provide a better understanding of its medium- to long-term performance. Of 124 Genesis II-related studies published in the literature, 11 met the eligibility criteria and were included in the final analysis. The included studies had a mean follow-up length of 38.1 months. Data from 1201 knees were available for review. Patients were an average of 70.5 years of age and predominantly female (63%). Findings indicated that the revision rate with this implant is low with up to 11.9 years of follow-up, with 14 revisions in total. The survival rate ranged from 100% at 1 and 2 years to 96.0% at 11.9 years. The mean Knee Society knee score improved 51.0 points from preoperative to postoperative evaluation. In conclusion, the Genesis II exhibited good clinical performance with up to 11 years follow-up, with an encouraging rate of survival and improvement in function. Additional studies with larger sample sizes and longer follow-up periods are needed to better understand the long-term performance of this implant.

Cost effectiveness of total knee arthroplasty from a health care providers' perspective before and after introduction of an interdisciplinary clinical pathway--is investment always improvement?

Background

Total knee arthroplasty (TKA) is an effective, but also cost-intensive health care intervention for end stage osteoarthritis. This investigation was designed to evaluate the cost-effectiveness of TKA before versus after introduction of an interdisciplinary clinical pathway from a University Orthopedic Surgery Department's cost perspective as an interdisciplinary full service health care provider.

Methods

A prospective trial recruited two sequential cohorts of 132 and 128 consecutive patients, who were interviewed by means of the WOMAC questionnaire. Direct process costs from the health care providers' perspective were estimated according to the German DRG calculation framework. The health economic evaluation was based on margiual cost-effectveness ratios (MCERs); an individual marginal cost effectiveness relation ≤ 100 € per % WOMAC index increase was considered as primary endpoint of the confirmatory cohort comparison. The interdisciplinary clinical pathway under consideration primarily consisted of a voluntary preoperative personal briefing of patients concerning postoperatively expectable progess in health status and optimum use of walking aids after surgery. All patients were supplied with written information on these topics, attendance of the personal briefing also included preoperative training for postoperative mobilisation by the Department's physiotherapeutic staff.

Results

An individual marginal cost effectiveness relation ≤ 100 €/% WOMAC index increase was found in 38% of the patients in the pre pathway implementation cohort versus in 30% of the post pathway implementation cohort (Fisher p = 0.278). Both cohorts showed substantial improvement in WOMAC scores (39 versus 35% in median), whereas the cohort did not differ significantly in the median WOMAC score before surgery (41% for the pre pathway cohort versus 44% for the post pathway cohort). Despite a locally significant decrease in costs (4303 versus 4194 € in median), the individual cost/benefit relation became worse after introduction of the pathway: for the first cohort the MCER was estimated 108 € per gained % WOMAC index increase (86 - 150 €/%) versus 118 €/% WOMAC gain (93 - 173 €/%) in the second cohort after pathway implementation. In summary, the proposed critical pathway for TKA could be shown to be significantly cost efficient, but not cost effective concerning functional outcome, when the above individual marginal cost effectiveness criterion was concentrated on.

Conclusions

The introduction of an interdisciplinary clinical pathway does not necessarily improve patient related outcomes. On the contrary, cost effectiveness from the health care providers' perspective may even turn out remarkably reduced in the setting considered here (functional outcome assessment after treatment by a full service health care provider).

MEDIUM-TERM ASSESSMENT OF TOTAL KNEE ARTHROPLASTY WITH IMPLANT MADE IN BRAZIL

Objective: This study assessed 47 patients who underwent total knee arthroplasty (TKA) with implants manufactured in Brazil, with a mean follow-up of five years. Methods: This was a retrospective study at Santa Casa de Misericordia Hospital in Rio de Janeiro, from January 1993 to December 2002. The sample comprised 47 patients (44 females and three males) who underwent TKA, totaling 58 knees. The patients’ ages ranged from 46 to 83 years. A diagnosis of osteoarthritis or rheumatic disease was confirmed in all the patients. Results: In this investigation, all the patients underwent cemented TKA with preservation of the posterior cruciate ligament. The length of follow-up ranged from 5 to 17 years. The functional assessment criterion used was the one of the Hospital for Special Surgery (HSS), and this yielded an average of 87 points after the operation. The radiographic criterion used was the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. We had three cases with a radiolucent line without implant loosening, which were asymptomatic from a clinical standpoint. Conclusion: The total knee arthroplasty procedures using an implant made in Brazil were performed by a trained and experienced team. To date, over the clinical follow-up on these patients with knee osteoarthritis or rheumatoid arthritis, the results have been seen to be satisfactory.

TOTAL KNEE ARTHROPLASTY IN A PATIENT WITH HOFFA FRACTURE PSEUDARTHROSIS: CASE REPORT

A rare occurrence of a case of Hoffa fracture pseudarthrosis in an alcoholic patient with genu valgum associated with venous insufficiency who underwent total knee arthroplasty is reported. The literature is reviewed and the main factors for surgical indication of total knee arthroplasty after a fracture of the knee are discussed. Total knee arthroplasty was a viable option in a 60-year-old patient with Hoffa fracture pseudarthrosis and comorbidities.

FRACTURE OF THE TIBIAL COMPONENT IN TOTAL KNEE ARTHROPLASTY: REPORT ON TWO CASES

The authors report the rare occurrence of two cases of fracture of the tibial component in total knee arthroplasty. They review the literature and discuss the main factors that can cause failure of the implants.

Current surgical treatment of knee osteoarthritis

Osteoathritis (OA) of the knee is common, and the chances of suffering from OA increase with age. Its treatment should be initially nonoperative-and requires both pharmacological and nonpharmacological treatment modalities. If conservative therapy fails, surgery should be considered. Surgical treatments for knee OA include arthroscopy, cartilage repair, osteotomy, and knee arthroplasty. Determining which of these procedures is most appropriate depends on several factors, including the location, stage of OA, comorbidities on the one side and patients suffering on the other side. Arthroscopic lavage and débridement is often carried out, but does not alter disease progression. If OA is limited to one compartment, unicompartmental knee arthroplasty or unloading osteotomy can be considered. They are recommended in young and active patients in regard to the risks and limited durability of total knee replacement. Total arthroplasty of the knee is a common and safe method in the elderly patients with advanced knee OA. This paper summarizes current surgical treatment strategies for knee OA, with a focus on the latest developments, indications and level of evidence.

Revision of tibial TKA components: bone loss is independent of cementing type and technique: an in vitro cadaver study

BACKGROUND

Different bone cements and various cementation techniques can lead to different bone loss in revision surgery. We investigated the degree of tibial bone loss depending on different cements and techniques.

METHODS

30 tibia specimens were matched into three groups (10 each). In all cases Genesis II tibia component were implanted. In two groups, the tibia base plate alone was cemented with Palacos® R+G and Refobacin® Bone Cement R. In the third group, both tibial base plate and tibial stem were cemented with Palacos® R+G. Afterwards, the specimens were axial loaded with 2000 N for 10,000 cycles. Tibial components were explanted and the required time to explantation was recorded. Bone loss after explantation was measured by CT.

RESULTS

On CT, there was no significant difference in bone loss between cementing techniques (p = 0.077; 95% CI -1.14 - 21.03) or the cements themselves (p = 0.345; 95% CI -6.05 - 16.70). The required time to explantation was 170.6 ± 54.89, 228.7 ± 84.5, and 145.7 ± 73.0 seconds in the first, second, and third groups, respectively.

CONCLUSIONS

Cement technique and type do not influence tibial bone loss in simulated revision surgery of the tibial component in knee arthroplasty.

No early tibial tray loosening after surface cementing technique in mobile-bearing TKA

Controversy still exists regarding which cementation technique of the tibial component is preferable. Full cementation showed excellent long-term outcomes, and surface cementation with fixed-bearing designs provided excellent mid-term results. Concerns have been expressed about possible rotary forces to the tibial rotating platform, when the tibial stem remains cementless, with the risk of early loosening. The purpose of this study was to evaluate the rate of early loosening and radiolucency lines in 70 consecutive unidirectional rotating platform, posterior stabilized, total knee arthroplasties, using surface cementation. Multivariate analysis was performed to identify any correlations between early loosening or radiolucency lines and clinically relevant covariates: age, sex, BMI, follow-up time, cement penetration, radiolucencies, tibial slope, femoral flexion, frontal alignment, pre-operative and post-operative Knee Scores. The tibial plateau was divided into four zones in antero-posterior view and into two zones in lateral view, and the cement penetration was evaluated in each zone. The mean follow-up was 43 months (SD 14), and the average patients' age was 73 (SD 7). The Knee Score averaged 91 (SD 8) and the Function score 86 (SD 17) at last follow-up visit. The cement penetration was >2 mm in all zones. No early loosening was detected, but in five asymptomatic patients (7%) radiolucency was noted around the tibial stem. The presence of radiolucent lines was not correlated with any of the covariates. The rate of early loosening and radiolucency lines with mobile tibial tray and surface cementation is comparable to other studies using different cementation techniques or surface cementation combined with fixed platform total knee arthroplasties.