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

Value comparison of humeral component press-fit and cemented techniques in reverse shoulder arthroplasty

BACKGROUND

Press-fit humeral fixation for reverse shoulder arthroplasty (RSA) has been shown to have loosening rates and outcomes similar to a cemented technique; however, increased value has not been reported. The purpose of this study was to determine whether the press-fit technique could improve the value of RSA using the procedure value index (PVI).

METHODS

Primary RSA patients with complete hospitalization cost data, preoperative and minimum 2-year postoperative Simple Shoulder Test (SST) scores, and postoperative satisfaction were included. The PVI was calculated as improvement in the SST score (in units of minimal clinically important difference) divided by total cost and normalized. Itemized cost data were obtained from hospital financial records and categorized. Radiographic complications, infections, and revisions were noted. Comparisons were made between the press-fit and cemented RSA cohorts.

RESULTS

A total of 176 primary RSA patients (83 cemented and 93 press fit) met the inclusion criteria (mean follow-up period, 44.6 months). Surgical indications (except failed rotator cuff repair), baseline SST scores, and demographic characteristics were similar. The calculated minimal clinically important difference for the SST score was 3.98. The average PVI was significantly greater in the press-fit cohort (1.51 vs 1.03, P < .001), representing a 47% difference. SST score improvement was not significantly different (P = .23). However, total hospitalization costs were significantly lower for the press-fit cohort ($10,048.89 vs $13,601.14; P < .001).

CONCLUSION

Use of a press-fit technique led to a 47% increase in value over a cemented technique. This appeared to be a function of decreased total costs rather than increased outcome scores.

A 9-Year Outcome Study Comparing Cancellous Titanium-Coated Cementless to Cemented Tibial Components of a Single Knee Arthroplasty Design

BACKGROUND

The cemented Advance Medial-Pivot total knee arthroplasty (TKA) was designed to reflect contemporary knee kinematics data and has shown satisfactory long-term outcomes.

METHODS

We retrospectively evaluated prospectively collected data from 2 groups of patients. Group A consisted of 54 patients (54 TKAs), 18 men and 36 women, and mean age at surgery was 63.2 ± 5.2 years; group B consisted of 54 patients (54 TKAs), 17 men and 37 women, and mean age at surgery was 63.8 ± 5.1 years. Patients of both groups were matched for age, gender, side, body mass index, and length of follow-up. The cementless components of this design were implanted in group A and the cemented in group B. Implant failure, complication rates, clinical (both subjective and objective) and radiological outcomes were assessed in all patients of both groups.

RESULTS

All patients of both groups were available for final follow-up evaluation at a mean of 8.6 ± 0.4 years. Survival analysis at 9 years showed a cumulative success rate of 100% in both groups with all end points. In neither group were implant-related, surgeon-related, or patient-related failures observed. When both groups were compared, in all time intervals, no differences were recorded on Knee Society system, Western Ontario and McMaster University Osteoarthritis Index, Short Form-12, and Oxford Knee Scores. On radiological examination, for both groups, all parameters evaluated were satisfactory.

CONCLUSION

This study presents satisfactory midterm clinical and radiological outcomes with the use of both versions of this design. Moreover, no implant-related failures were observed with the use of cancellous titanium-coated tibial implants.

Survival of the low contact stress rotating platform total knee replacement is influenced by age: 1058 implants with a minimum follow-up of 10 years

BACKGROUND

The low contact stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimise polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated. The primary aim of this study was to assess long-term survivorship of the LCS TKR performed at a single high-volume centre. Secondary aims were to assess survival by mechanism of failure and identify predictors of revision.

METHODS

During a 13-year period (1993-2006) 1091 LCS TKRs were performed by two senior surgeons. Thirty-three with incomplete data were excluded. The patients were retrospectively identified from an arthroplasty register. Mean age was 69 (range 30-96) years. Five hundred seventy-seven TKRs were performed in females, 481 in males. Mean follow-up was 14 years (SD 4.3).

RESULTS

There were 59 revisions during the study period: 14 (23.7%) for infection, 18 (30.5%) for instability, and 27 (45.8%) for polyethylene wear. Three hundred ninety-two patients died. All-cause survival at 10 years was 95% (95%CI 91.7-98.3) and at 15 years was 93% (95%CI 88.6-97.8). Survival at 10 years according to mechanism of failure was: infection 99% (95%CI 94-100%), instability 98% (95%CI 94-100%), and polyethylene wear 98% (95%CI 92-100). Of the 27 with polyethylene wear, only 19 (70.4%) had osteolysis requiring component revision, the other eight (29.6%) had polyethylene exchanges. Cox regression analysis identified younger age as the only predictor of revision (HR 0.96, 95%CI 0.94-0.99, p = 0.003), with a four percent decreased risk of revision for each increase in year of age.

CONCLUSIONS

The LCS TKR demonstrates excellent long-term survivorship with a low rate of revision for osteolysis, however this risk is increased in younger patients.

Deformity correction with total knee arthroplasty for severe knee osteoarthritis accompanying extra-articular femoral deformity: the results are promising

PURPOSE

This study aimed to evaluate patients with severe degenerative osteoarthritis of the knee and extra-articular femoral deformities treated with total knee arthroplasty (TKA) and acute deformity correction.

METHODS

Ten patients with severe degenerative osteoarthritis of the knee and extra-articular femoral deformities were included, and the median age was 63 years (range 38-67). The etiology was post-traumatic malunion in four patients, rickets sequelae in four patients, and surgical sequelae due to multiple epiphyseal dysplasia in two patients. The severity of degenerative osteoarthritis and deformity analyses were assessed according to the Kellgren-Lawrence and Paley criteria, respectively. The median number of previous operations the patients had undergone was two (range 0-3), and the median Oxford Knee Society score was 9 (range 5-13) before treatment. All patients were treated with primary TKA and deformity correction in the same surgery. The TKA was completed first, followed by an osteotomy at the apex of the deformity. Finally, a retrograde intramedullary nail was inserted.

RESULTS

The median follow-up period was 44 (31-60) months. A stable and functional knee joint, a physiological mechanical axis, and solid osseous union were achieved in all patients. Late prosthetic failure was seen in one patient due to deep infection. The median Oxford Knee Society score was 42 (range 37-47) at the final follow-up.

CONCLUSIONS

Combining several procedures in single setting for the treatment of severe knee osteoarthritis accompanied by extra-articular deformity may eliminate the need for multiple surgeries. Furthermore, a proper physiological mechanical axis can be obtained without causing substantial bone loss.

LEVEL OF EVIDENCE

IV.

Midterm Results of Cementless Total Knee Arthroplasty: A Retrospective Case Series

Background:

There is an ongoing debate about whether to use cementless or cemented fixation for Total Knee Arthroplasty (TKA).

Objective:

The study aimed to assess midterm survivorship of the Vanguard cementless system, and to demonstrate the utility of the Bone Hardness Test (BHT) for the selection of cementless fixation TKA.

Methods:

From September 2009 through November 2014, 123 total knee arthroplasties were completed, with cementless Vanguard Cruciate Retaining TKA in 110 knees (102 patients) and cemented Vanguard in 13 cases (12 patients). Implant fixation was based on intraoperative assessment of posterior cruciate ligament stability, bone quality, and BHT. All patients with a cementless Vanguard implant were eligible for this retrospective study. Preoperative and postoperative Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index were obtained. Standardized standing anteroposterior and lateral radiographs were taken.

Results:

Three patients (4 TKAs) were lost to follow-up. The mean follow-up time was 5.5 ± 1.4 years. All scores significantly improved postoperatively. No radiographic failures were observed. Five-year implant survival, with revision of any component for any reason as an endpoint, was 97.2% (95% confidence interval, 91.7 - 99.1%). Five-year survival with revision for aseptic loosening was 100%. Only one knee required revision due to an isolated unrelated bearing exchange, and two additional knees required secondary resurfacing of the patella for retropatellar pain.

Conclusion:

Good midterm results were obtained with the cementless Vanguard Cruciate Retaining TKA for the treatment of osteoarthritis. The Bone Hardness Test appears to be an effective way to determine the selection of cementless TKA.

A prospective evaluation of a largely cementless total knee arthroplasty cohort without patellar resurfacing: 10-year outcomes and survivorship

BACKGROUND

The theoretical benefits of a mobile bearing design in Total Knee Arthroplasty (TKA) include increased articular surface conformity with a reduction in both polyethylene wear and implant interface shear. However, to date these theoretical advantages have not been translated into published evidence of superior survivorship. This paper presents the results of a prospective, non-comparative study evaluating the performance of the mobile bearing Low Contact Stress LCS Complete Rotating Platform TKA in a largely cementless cohort without patellar resurfacing.

METHODS

237 consecutive patients (240 knees) undergoing primary TKA were prospectively recruited. All received the LCS Complete Rotating Platform TKA (DePuy International, Leeds, UK). Clinical and radiographic assessments were performed at 3, 12, 60 and 120 months post-operatively. Radiographic evaluation was performed by an independent external surgeon.

RESULTS

The mean age was 70.3 years. 77.5% of cases were cementless. Radiographic assessment suggested excellent femoral component fixation. 22 tibial radiolucent lines (RLLs) > 1 mm were observed in 12 knees. No RLLs were progressive. There have been two revisions; one for late infection and one for aseptic loosening. No patients underwent secondary patellar resurfacing. The cumulative implant survivorship, using component revision for any reason as the endpoint, was 98.9% (95% CI, 95.6 to 99.7%) at 10 years.

CONCLUSIONS

The excellent survivorship at a minimum 10-year follow-up supports the use of uncemented porous coated fixation without patellar resurfacing with the non-posterior stabilized LCS Complete Rotating Platform TKA.

The Proximal and Distal Femoral Canal Geometry Influences Cementless Stem Anchorage and Revision Hip and Knee Implant Stability

Although cementless revision arthroplasty of the hip has become the gold standard, revision arthroplasty of the distal femur is controversial. This study evaluated the anchoring principles of different femoral revision stem designs in extended bone defect situations, taking into account the anatomical conditions of the proximal and distal femur, and the resulting primary stability. Cementless press-fit stems of 4 different designs were implanted in synthetic femurs. The specimens were analyzed by computed tomography and were tested considering axial/torsional stiffness and migration resistance. Different stem designs anchored in different femoral canal geometries achieved comparable primary stability. Despite considerably different anchorage lengths, no difference in migration behavior or stiffness was found. Both in the distal femur and in the proximal femur, the conical stems showed a combination of conical and 3-point anchorage. Regarding the cylindrical stem tested, a much shorter anchorage length was sufficient in the distal femur to achieve comparable primary stability. In the investigated osseous defect model, the stem design (conical vs cylindrical), not the geometry of the femoral canal (proximal vs distal), was decisive regarding the circumferential anchorage length. For the conical stems, it can be postulated that there are reserves available for achieving a conical-circular fixation as a result of the large contact length. For the cylindrical stems, only a small reserve for a stable anchorage can be assumed. [Orthopedics. 2018; 41(3):e369-e375.].

No difference in implant survivorship and clinical outcomes between full-cementless and full-cemented fixation in primary total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

The debate over the use of cemented or cementless fixation in total knee arthroplasty (TKA) has never stopped since cementless fixation was introduced. We undertook a systematic review and meta-analysis to evaluate the optimal mode of fixation (full-cementless vs. full-cemented) in TKA.

METHODS

PubMed, Embase, and the Cochrane Library databases up to July 2017 were searched to identify randomised controlled trials (RCTs) and quasi-RCTs comparing full-cementless TKA and full-cemented TKA. The primary outcome was implant survivorship. Secondary outcomes included radiological outcomes (maximum total point-motion [MTPM], radiolucent line, rotation degree) and clinical outcomes (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] score, Knee Society Score [KSS] score, postoperative range of movement, blood loss and complications).

RESULTS

Seven studies were included in the systematic review and meta-analysis. The mean follow-up was 7.1 years (range from 2 to 16.6 years). There was no difference in implant survivorship (RR, 0.98; 95% CI, 0.95-1.01; p = 0.25; I² = 0%), MTPM (weighted mean difference [WMD], 0.13 mm; 95% CI, -0.69-0.95; p = 0.75; I² = 89.3%) and radiolucent line (RR, 1.36; 95% CI, 0.57-3.23; p = 0.48; I² = 54%) between the cementless and cemented methods. There was a mean 0.22° more rotation in the full-cementless fixation group (95% CI, 0.13-0.32; p < 0.01; I² = 28.5%). There were no significant differences relating to clinical outcomes (WOMAC score, KSS score, postoperative range of movement, blood loss and complications) between the two fixation groups.

CONCLUSIONS

Although more overall component rotation is found in full-cementless fixation, the implant survivorship and clinical efficacy are likely similar between full-cementless and full-cemented fixation. However, future RCTs with similar cementless prosthetic coating and longer-term follow-up are still needed to confirm our findings.

Long-term outcomes of over 8,000 medial Oxford Phase 3 Unicompartmental Knees-a systematic review

Background and purpose - There is debate as to the relative merits of unicompartmental and total knee arthroplasty (UKA, TKA). Although the designer surgeons have achieved good results with the Oxford UKA there is concern over the reproducibility of these outcomes. Therefore, we evaluated published long-term outcomes of the Oxford Phase 3 UKA. Patients and methods - We searched databases to identify studies reporting ≥10 year outcomes of the medial Oxford Phase 3 UKA. Revision, non-revision, and re-operation rates were calculated per 100 component years (% pa). Results - 15 studies with 8,658 knees were included. The annual revision rate was 0.74% pa (95% CI 0.67-0.81, n = 8,406) corresponding to a 10-year survival of 93% and 15-year survival of 89%. The non-revision re-operation rate was 0.19% pa (95% CI 0.13-0.25, n = 3,482). The re-operation rate was 0.89% pa (95% CI 0.77-1.02, n = 3,482). The most common causes of revision were lateral disease progression (1.42%), aseptic loosening (1.25%), bearing dislocation (0.58%), and pain (0.57%) (n = 8,658). Average OKS scores were 40 at 10 years (n = 3,417). The incidence of medical complications was 0.83% (n = 1,443). Interpretation - Very good outcomes were achieved by both designer and non-designer surgeons. The PROMs, medical complication rate, and non-revision re-operation rate were better than those found in meta-analyses and publications for TKA but the revision rate was higher. However, if failure is considered to be all re-operations and not just revisions, then the failure rate of UKA was less than that of TKA.

Cemented or cementless total knee arthroplasty? - Comparative results of 200 cases at a minimum follow-up of 11 years

INTRODUCTION

Since 1996 we have been using cementless fixation with hydroxyapatite (HA) coating. The purpose of this paper is to compare survivorship of a series of 100 cemented Total Knee Arthroplasty (TKA) to a similar series of 100 cementless with a follow up of 11-16 years. Material methods: Both TKA are mobile bearing total knee postero-stabilized. They can be used with cement or without cement. Among 1030 New Wave TKATM implanted from 2002 to 2015 we have identified 100 cemented TKAs and 100 cementless TKAs. All these cases were primary replacement. Differences in survival probability were determined using log-rank test.

RESULTS

Survival probabilities at 11 years of follow-up were: Cemented group: 90.2% CI95% [81.9-94.8]; Cementless group: 95.4% CI95% [88.1-98.2]. Comparison between both group showed significant difference, p = 0.32.

DISCUSSION

The advantages of cementless TKA are bone stock preservation, cement debris protection and the potential to achieve biologic fixation. Cementless implants rely on a porous or roughened surface to facilitate bone formation. HA has been shown to accelerate bone integration and to decrease micro motion of the components and to increase fixation. With a survival probability of 90.2% (cemented version) and 95.4% (cementless version), this total knee prosthesis performs as intended in primary total knee arthroplasty. No statistical differences could be found between cemented and cementless implants.

Clinical Evaluation of Efficacy and Performance of All-Poly Tibial Freedom® Total Knee System for Treating Osteoarthritis Patients: Three-Year Follow Up Study

Introduction

Advancement in technology in terms of design and building materials has made Total Knee Replacement (TKR) a highly effective, safe, and predictable orthopedic procedure.

Aim

To review the clinical outcomes for efficacy and performance of Freedom Total Knee System for the management of Osteoarthritis (OA), at a minimum of three years follow up.

Materials and Methods

For this retrospective, post-marketing study, clinical data of patients treated with Freedom Total Knee System was retrieved from the clinical records after approval from the Institutional Ethics Committee . All the patients above the age of 18 years who completed at least three years after TKR were observed for the study purpose. Patients treated for OA were included while the patients who received the implant for treatment of rheumatoid arthritis and traumatic injury were excluded. Factors such as aseptic loosening, implant failure, and need for revision surgery were observed to evaluate implant performance. Cases were recruited for clinical assessment of primary efficacy endpoint in terms of post-surgery maximun range of motion. Secondary efficacy endpoint was to determine the clinical and social quality of life as per the American Knee Society Score (AKSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and stiffness scores.

Results

A total of 158 patients who had 191 TKR were observed for performance. The mean age of the patients was 67.67 years; mean BMI was 28.97±3.33, and the group comprised of 43% men and 57% women. Telephonic follow up at three years of 158 patients identified that none of them required revision surgery or had aseptic loosening suggesting excellent performance. Final clinical follow up at three years was available for only 35 patients (41 knee implants). The range of motion significantly improved from preoperative 104°±5.67° (range, 85°-119°) to 119.8°±11.05° (98°-123°) at follow-up (p<0.05). There was a significant improvement in clinical and functional AKSS score and WOMAC score at follow-up.

Conclusion

The evaluation of Freedom Total Knee System for TKR in treating OA, at a minimum of three years follow up showed excellent outcomes in terms of performance, range of motion, reduced postoperative stiffness and pain, and improved functionality.

Fixation and clinical outcome of uncemented peri-apatite-coated versus cemented total knee arthroplasty

Aims

The optimal method of tibial component fixation remains uncertain in total knee arthroplasty (TKA). Hydroxyapatite coatings have been applied to improve bone ingrowth in uncemented designs, but may only coat the directly accessible surface. As peri-apatite (PA) is solution deposited, this may increase the coverage of the implant surface and thereby fixation. We assessed the tibial component fixation of uncemented PA-coated TKAs versus cemented TKAs.

Patients and Methods

Patients were randomised to PA-coated or cemented TKAs. In 60 patients (30 in each group), radiostereometric analysis of tibial component migration was evaluated as the primary outcome at baseline, three months post-operatively and at one, two and five years. A linear mixed-effects model was used to analyse the repeated measurements.

Results

After five years of follow-up, one (cemented) component was revised due to ligament instability. Overall, uncemented PA-coated tibial components migrated significantly more (p = 0.003), with the mean maximum total point motion (MTPM) at five years being 0.62 mm (95% confidence intervals (CI) 0.49 to 0.76) for cemented tibial components and 0.97 mm (95% CI 0.81 to 1.15) for PA-coated tibial components in TKA. However, between three months and five years the cemented TKAs migrated significantly more (p = 0.02), displaying a MTPM of 0.27 mm (95% CI, 0.19 to 0.36) versus 0.13 mm (95% CI, 0.01 to 0.25) for PA-coated tibial components. One implant in each group was considered at risk for aseptic loosening due to continuous migration after five years of follow-up, albeit with different migration patterns for each group (i.e. higher initial migration but diminishing over time for the PA-coated component versus gradually increasing migration for the cemented component).

Conclusion

The tibial components of PA-coated TKAs showed more overall migration compared with the tibial components of cemented TKAs. However, post hoc analysis showed that this difference was caused by higher migration of PA-coated components in the first three months, after which a stable migration pattern was observed. Clinically, there was no significant difference in outcome between the groups. Cite this article: Bone Joint J 2017;99-B:1467–76.

Cementless knee arthroplasty

Total knee replacement is a common treatment for advanced knee osteoarthritis. The most common and widespread method is cemented arthroplasty. As in the prosthetic hip a gradual transition from cemented to uncemented fixation techniques occurred over time, increasing interest is growing also around cementless knee fixation, with the theoretical advantages of preserving the bone stock and obtaining a biological fixation avoiding cement fragmentation. On the basis of the actual knowledge, the uncemented knee prosthesis represents an interesting alternative especially for the patient under 65 years of age, with viable bone quality, in which a biological bone-prosthesis fixation is desirable, while avoiding the drawbacks of cement fragmentation and of the possible future revision of a cemented implant. However the weak link remains the tibial fixation, so that technical tips are important to avoid micromovements with subsequent lack of osteointegration. In our experience, gap balancing, mobile bearings and no haemostatic tourniquet well combine with this kind of implant.

Good long-term results following cementless TKA with a titanium plasma coating

PURPOSE

While cemented total knee arthroplasty (TKA) is currently the gold standard for primary osteoarthritis, cementless component fixation has achieved increasingly comparable outcomes due to improvements in both implant designs and surgical technique. Long-term outcomes and survivorship with the TC-Plus cementless, titanium plasma-coated TKA system without patella resurfacing were evaluated.

METHODS

A homogenous population of 171 consecutive patients who received 206 primary TC-Plus TKAs without patella resurfacing over a 19-year period was retrospectively reviewed. Knee Society Clinical Rating System (KSCRS) scores were obtained, and radiographic evaluation was performed after a mean follow-up of 13.2 ± 8.4 years. Survivorship analysis was made with endpoints revision for any reason and aseptic loss of biological fixation.

RESULTS

One hundred and thirty-six TKAs implanted in 113 patients were available for analysis. Mean KSCRS clinical and functional scores improved significantly versus preoperative values. No radiological loss of biological fixation of femoral and tibial components was observed. Survival with aseptic revision of any component as the endpoint was 95.7 % (95 % confidence interval (CI) 91.7-97.9 %) and 93.6 % (95 % CI 87.8-96.6 %) at 10 and 15 years, respectively.

CONCLUSION

Titanium plasma-coated cementless TKA without patella resurfacing showed excellent long-term results, with high 10- and 15-year component survival rates. The clinical and radiological results were comparable to those of other cementless TKAs, providing further evidence for the non-cemented resurfacing of the osteoarthritic knee.

LEVEL OF EVIDENCE

IV.

Initial Stability of Cemented vs Cementless Tibial Components Under Cyclic Load

BACKGROUND

Cement fixation of total knee components remains the gold standard despite resurgence in cementless fixation with the goal of long-term durable fixation. Initial stability is paramount to achieve bony ingrowth of cementless components.

METHODS

Twelve cemented and cementless tibial baseplates were implanted into sawbones and tested using a physiological medial-lateral load distribution for 10,000 cycles to represent 8 weeks of in vivo function. Micromotion was measured at 5 locations around the baseplate during loading.

RESULTS

Cycling had a significant effect on the change in micromotion between maximum and minimum loads at the anterior, medial, lateral, posteromedial, and posterolateral tray edge locations. A significant effect of fixation technique was detected for the anterior (P < .001), medial (P = .002), and lateral (P = .0056) locations but not for the posteromedial (P = .36) or posterolateral (P = .82) locations. Differences in micromotion between cemented and cementless components did not exceed 150 μm at any tested location.

CONCLUSION

The micromotion experienced by cementless tibial components in the present study may indicate a lower initial mechanical stability than the cemented group. However, this difference in initial stability may be subclinical because the differences between average cemented and cementless micromotion were <150 μm at all measured locations under the loading regime implemented.

Total Knee Arthroplasty for Osteoarthritis in Patients Less Than Fifty-Five Years of Age: A Systematic Review

BACKGROUND

The proportion of younger patients undergoing total knee arthroplasty (TKA) is increasing and predictions state that the <55 age group will be the fastest growing group by 2030. We aim to collate data across studies to assess functional outcomes following TKA in patients <55 years of age using a systematic review.

METHODS

The search identified 980 studies for title and abstract review. Forty-three full texts were then assessed. Thirteen studies underwent quality assessment and data extraction. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed throughout. Outcomes extracted included pre-operative and post-operative functional scores, range of motion, and patient satisfaction. Clinical complications and survival were also recorded.

RESULTS

Across 13 studies we were able to demonstrate 54-point improvement in clinical Knee Society Score and a 46-point improvement on functional Knee Society Score. A 2.9° improvement in range of motion was found at final follow-up. Satisfaction rate was 85.5%. Cumulative percentage all-cause revision rate was 5.4% across 1283 TKAs at a mean 10.8 years of follow-up. Ten-year survival, for aseptic loosening alone, was 98.2%.

CONCLUSION

TKA is an excellent treatment option for the young osteoarthritic knee with a >50% improvement in functional knee scores. Satisfaction is high and the revision rate remains 0.5% per year.

Outcomes of Newer Generation Cementless Total Knee Arthroplasty: Beaded Periapatite-Coated vs Highly Porous Titanium-Coated Implants

BACKGROUND

Newer generation cementless total knee arthroplasty (TKA) designs are available and have novel implant coatings. We evaluated and compared beaded periapatite (PA)-coated vs highly porous titanium-coated cementless TKAs. Specifically, we compared: (1) survivorship, (2) Knee Society Scores (KSSs) and range of motion, (3) complications, and (4) radiographic findings.

METHODS

There were 805 TKAs with beaded PA-coated tibial and patellar components (PA group; mean age 67 years; range 41-86 years), and 219 TKAs with highly porous titanium-coated tibial and patella components (mean age 66 years; range 34-88 years). Mean follow-up was 4.4 years (range 2-9 years; median 4 years). Implant survivorship was calculated using Kaplan-Meier curves. Student t-tests and chi-square tests were used as appropriate. Radiographic evaluation was performed using Knee Society Roentgenographic Evaluation and Scoring System.

RESULTS

All-cause implant survivorship in beaded PA-coated group was 99.5% (95% CI, 97.9%-99.9%) and 99.5% (95% CI, 92.7%-99.9%) in highly porous titanium-coated group. There were no significant differences in the KSS for pain and function. Improvement in flexion and extension was similar in the 2 groups. Overall, complication rate (2.2% vs 2.3%; P = .274) and number of revisions (6 [0.8%] vs 2 [0.2%]; P = .936) were similar in the 2 groups. Excluding the aseptic and septic failures, there were no progressive radiolucencies or osteolysis on radiographic evaluation.

CONCLUSION

This study has shown good clinical and patient-reported outcomes of cementless TKA for both implants. Future multicenter large scale clinical and cost-effectiveness studies are needed to determine the superiority of one cementless implant type over the other.

No difference between cemented and cementless total knee arthroplasty in young patients: a review of the evidence

PURPOSE

The present piece of work provides improved knowledge about the evidence related to TKA in patients 60 years of age or younger, with special focus on fixation methods. Main concern of the review is to analyse the difference of survival rate and complications of cemented and cementless implants.

METHODS

An electronic search was carried out between October and December 2015, through CINAHL, PubMed and the Cochrane Central Registry of Controlled Trials web databases. Articles in English, Italian, French and Spanish were considered for inclusion. Only peer-reviewed studies with adult patients aged 60 years or less, with diagnosis of osteoarthritis in more than 90% of the subjects, were considered for inclusion. All studies had to report outcomes after TKA with either cemented or cementless fixation technique.

RESULTS

No significant differences in terms of clinical, functional and radiological outcomes were found between cemented and cementless implants. Good clinical and functional results were obtained in terms of the Knee Society score and Western Ontario and McMaster Universities Osteoarthritis Index for both techniques. Radiographic results showed that radiolucent lines of <2 mm in width were detected at radiographs, without difference between cemented or cementless implants. Well-conducted trials on cemented versus cementless TKA were carried out in few papers. A survival rate of over 90% was reported in the majority of the studies at a mean follow-up of 8.6 years (range 5-18 years).

CONCLUSION

Similar results were observed in terms of functional outcome and survival rates for both cemented and cementless TKAs. High survival rates were reported for both operative techniques and cemented TKA did not offer additional benefit. Assuming that cementless prosthesis allows a stable fixation and reduces the time of operation, the authors recommend the cementless fixation as a primary choice in the investigated patient population. However, evidence is low, and further research is needed.

LEVEL OF EVIDENCE

IV.

Contemporary failure aetiologies of the primary, posterior-stabilised total knee arthroplasty

Aims

The number of revision total knee arthroplasties (TKA) that are performed is expected to increase. However, previous reports of the causes of failure after TKA are limited in that they report the causes at specific institutions, which are often dependent on referral patterns. Our aim was to report the most common indications for re-operations and revisions in a large series of posterior-stabilised TKAs undertaken at a single institution, excluding referrals from elsewhere, which may bias the causes of failure.

Patients and Methods

A total of 5098 TKAs which were undertaken between 2000 and 2012 were included in the study. Re-operations, revisions with modular component exchange, and revisions with non-modular component replacement or removal were identified from the medical records. The mean follow-up was five years (two to 12).

Results

The Kaplan-Meier ten-year survival without a re-operation, modular component revision and non-modular component revision was 95.7%, 99.3% and 95.3%, respectively. The most common indications for a re-operation were: post-operative stiffness (58%), delayed wound healing (21%), and patellar clunk (11%). The indications for isolated modular component revision were acute periprosthetic joint infection (PJI) (64%) and instability (36%). The most common indications for non-modular component revision were chronic PJI (52%), aseptic loosening (17%), periprosthetic fracture (10%), and instability (10%).

Conclusion

Post-operative stiffness remains the most common indication for re-operation after TKA. Infection is the most common indication for modular and non-modular component revision. Aseptic loosening was not an uncommon cause of failure, however, it was much less common than in national registry and non-registry data. Focusing on posterior-stabilised TKAs initially performed at our institution allowed for an accurate assessment of the causes of failure in a contemporary specialty practice. Cite this article: Bone Joint J 2017;99-B:647–52.

Cementless Porous Tantalum Monoblock Tibia vs Cemented Modular Tibia in Primary Total Knee Arthroplasty: A Meta-Analysis

BACKGROUND

With the introduction of new fixation systems and designs, there has been a recent reemergence of interest in cementless fixation of the tibial component in total knee arthroplasty. However, little is known regarding the clinical features and survivorship of the cementless porous tantalum monoblock tibial component compared to the conventional cemented modular tibial component.

METHODS

We conducted a literature search of multiple databases for comparative studies published before June 2015 that investigated the outcomes of cementless porous tantalum monoblock tibia vs conventional cemented modular tibia. A pooled analysis was performed. The outcomes of interest were postoperative functional score, range of motion, Western Ontario and McMaster University Osteoarthritis Index, total complications, reoperation, radiolucent lines, loosening of the tibial component, and length of operation.

RESULTS

Six studies involving 977 patients were eligible for the meta-analysis. The use of a cementless porous tantalum monoblock tibial component may associate with a slightly higher functional score, fewer radiolucent lines, and shorter operation. No significant difference was seen in regard to the range of motion, Western Ontario and McMaster University Osteoarthritis Index, total complications, reoperation, and loosening of the component between the 2 groups.

CONCLUSION

However, due to variation among the included studies, the use of cementless porous tantalum monoblock tibia seems to achieve no substantial superiority over that of the conventional cemented modular tibia at 5-year follow-up. Data concerning the long-term prognosis of this novel implant should continue to be collected and analyzed.

Total Knee Arthroplasty Using Cementless Porous Tantalum Monoblock Tibial Component: A Minimum 10-Year Follow-Up

BACKGROUND

Cementless fixation in total knee arthroplasty (TKA) was introduced to improve the longevity of implants but has yet to be widely adopted because of reports of higher failure rates in some series. The cementless tantalum monoblock tibial component, in contrast, has shown successful short-term results, but long-term survivorship with this design is still lacking. The purpose of this study was to investigate the minimum 10-year clinical and radiographic results of the cementless tantalum monoblock tibial component in primary TKA.

METHODS

From March 2002 to March 2005, 33 patients (33 knees) underwent primary TKA with a cementless tantalum monoblock tibial component. All patients were followed clinically and radiographically for a minimum of 10 years (mean 11.5 years, range 10-13 years). No patients were lost to follow-up. The underlying diagnosis that led to the primary TKA was primary osteoarthritis in 31 knees and post-traumatic osteoarthritis in 2 knees.

RESULTS

None of the components was revised. At a minimum 10-year follow-up, the survivorship with reoperation for any reason as end point was 96.9%. With tibial component revision for aseptic loosening or osteolysis as the end point survivorship was 100%. There was no radiographic evidence of tibial component loosening, subsidence, osteolysis, or migration at the time of the latest follow-up. The mean Knee Society knee scores improved from 56 points preoperatively to 93 points at the last clinical visit.

CONCLUSION

The porous tantalum tibial monoblock component demonstrated excellent clinical and radiographic outcomes with no component revisions for aseptic loosening at a minimum follow-up of 10 years.

Cementless total knee arthroplasty

As the number of younger and more active patients treated with total knee arthroplasty (TKA) continues to increase, consideration of better fixation as a means of improving implant longevity is required. Cemented TKA remains the reference standard with the largest body of evidence and the longest follow-up to support its use. However, cementless TKA, may offer the opportunity of a more bone-sparing procedure with long lasting biological fixation to the bone. We undertook a review of the literature examining advances of cementless TKA and the reported results.

Cite this article: Bone Joint J 2016;98-B:867–73.

Early radiographic and functional outcomes of a cancellous titanium-coated tibial component for total knee arthroplasty

BACKGROUND

Various surface coatings have been developed over the past decades to enhance fixation of cementless total knee arthroplasty (TKA). BIOFOAM(®) (MicroPort Orthopedics Inc., Arlington, TN, USA) is a novel cancellous titanium surface coating intended to increase both initial and long-term fixation. The purpose of this study was to investigate the early functional and radiographic outcomes of this coating used in a TKA application.

MATERIALS AND METHODS

One hundred and four (104) primary TKAs in 85 subjects using BIOFOAM-coated tibial components were prospectively enrolled at four centers. Subjects were evaluated using Knee Society Scores and radiographic analysis at a minimum follow-up of 24 months.

RESULTS

Knee Society Scores and flexion were all significantly improved at final follow-up compared to baseline. Radiographic analyses were satisfactory, with no progressive radiolucencies and only a single subject presenting with a radiolucency surrounding a tibial component. There were two revisions in the cohort: one for instability following a ruptured lateral collateral ligament and one for recurrent tibial insert dislocation.

CONCLUSIONS

This is the first study to report clinical outcomes associated with the BIOFOAM coating used in a cementless TKA application. Early functional scores and radiographic analyses are promising, but further investigations are needed to confirm long-term clinical success with these components.

Similar survival between uncemented and cemented fixation prostheses in total knee arthroplasty: a meta-analysis and systematic comparative analysis using registers

PURPOSE

The purpose of this analysis was to determine whether uncemented total knee arthroplasty performs as well as cemented total knee arthroplasty.

METHODS

We searched PubMed, MEDLINE, and EMBASE, and major orthopaedic journals. This search was performed for the years from 1980 to the present. Randomised controlled trials and observational studies comparing cemented and uncemented fixation were identified. Effective data were pooled for meta-analysis. A systematic search was carried out using the EFORT website to identify the relevant arthroplasty registers.

RESULTS

Nine studies were included in the meta-analysis. The combined odds ratio for failure of the implant due to aseptic loosening for the uncemented group over 5 and 10 years were 3.41 (p = 0.0001) and 4.73 (p = 0.0002), respectively. Subgroup analysis of data when design-related failed total knee arthroplasty (TKA)s were excluded showed no difference between the groups for odds of aseptic loosening (n.s.). There was no difference between the groups with respect to infection (n.s.). Pooled outcome of register data revealed that uncemented knees had a higher revision rate than cemented knees.

CONCLUSIONS

The important finding from the current study is that there is no evidence to support that fixation techniques alone affect the durability of a total knee arthroplasty when design-related failure in TKAs was excluded. The way of fixation is not relevant to the incidence of infection.

LEVEL OF EVIDENCE

IV.

Cemented versus cementless fixation of a tibial component in LCS mobile-bearing total knee arthroplasty performed by a single surgeon

Although cemented tibial fixation of total knee arthroplasty accepted as the gold standard, cementless fixation as a means to supplement disadvantages of cemented fixation continues to be of interest to clinicians. One hundred sixty-eight consecutive knees undergoing primary knee arthroplasty for osteoarthritis were randomly assigned to receive either a cemented (86 knees) or cementless (82 knees) fixation of tibial component. We report the outcomes at 8 to 11years (mean, 9.5). The mean KSS, the HSS score, the mean WOMAC, the mean ranges of knee movement and radiological results were similar in both groups. No osteolysis was identified in either group. The rate of survival of the femoral and tibial components was 100% in both groups at final follow-up.

Why are total knee arthroplasties failing today--has anything changed after 10 years?

The purpose of this study was to determine the frequency and cause of failure after total knee arthroplasty and compare the results with those reported by our similar investigation conducted 10 years ago. A total of 781 revision TKAs performed at our institution over the past 10 years were identified. The most common failure mechanisms were: loosening (39.9%), infection (27.4%), instability (7.5%), periprosthetic fracture (4.7%), and arthrofibrosis (4.5%). Infection was the most common failure mechanism for early revision (<2 years from primary) and aseptic loosening was the most common reason for late revision. Polyethylene (PE) wear was no longer the major cause of failure. Compared to our previous report, the percentage of revisions performed for polyethylene wear, instability, arthrofibrosis, malalignment and extensor mechanism deficiency has decreased.

Bone mineral density of the femur in autopsy retrieved total knee arthroplasties

Bone mineral density (BMD), as measured by DEXA, can vary depending on bone rotation and fat content of soft tissues. We performed DEXA measurements, under controlled positioning, on 24 autopsy-retrieved femora from patients who had fully functional and asymptomatic successful TKA to determine periprosthetic BMD changes and compared results to 24 normal cadaveric femora. In TKA specimens, BMD was affected by gender, preoperative diagnosis, and zone under analysis. The lowest mean BMD was in the anterior femoral condylar zone. Males had higher mean BMD at all zones while patients with preoperative diagnosis of osteoarthritis had higher BMD in the posterior condylar zone. The mean BMD in the anterior femoral condylar zone in TKA specimens was significantly lower than in normal specimens without arthroplasties, most likely due to stress shielding.

The Rotaglide mobile-bearing total knee arthroplasty: no difference between cemented and hybrid implantation

PURPOSE

The optimal fixation of the Rotaglide total knee arthroplasty's (TKA) components is controversial. It is hypothesized that the hybrid fixation (cementless femoral component) in a mobile-bearing TKA system might cause increased rate of loosening--especially in the femoral part--and finally failure of the arthroplasty. Consequently, the aim of this study was to compare the survival and revision rates and also the clinical and radiological outcomes of the cemented and hybrid fixation of the Rotaglide TKA.

METHODS

One hundred patients, who underwent TKA with the Rotaglide prosthesis, were randomly placed in two groups. In the first group, the prosthesis was cemented, and in the second group, the hybrid technique was used. Revision and mortality rates were compared after 8-12 years of follow-up. Knee and Osteoarthritis Outcome Score (KOOS) questionnaire and the Knee Society Roentgenographic Evaluation and Scoring System were used to demonstrate clinical and radiographic differences.

RESULTS

There were no statistically significant differences in revision (n.s.) or mortality (n.s.) rates between the two treatment arms. The clinical outcome at the time of last follow-up (mean 9.5 years, SD ± 1.4) ranged from very good to excellent (77.8 ± 17.5 for the cemented group and 77.2 ± 20.4 for the hybrid group). No statistically significant differences in all KOOS subscales. Radiographs showed no significant difference in prosthesis alignment and no evidence of loosening between groups.

CONCLUSION

The hypothesis that the hybrid fixation in a mobile-bearing TKA system might cause increased rate of loosening and finally failure of the arthroplasty was not confirmed. The fixation technique (cemented or hybrid) had no influence on the prosthesis's survivorship, and also on mortality rates, clinical and radiographic outcomes in a mean follow-up time of 9.5 ± 1.4 years. The Rotaglide TKA is a safe and reliable prosthesis regardless the fixation technique.

Similar survival between screw cementless and cemented tibial components in young patients with osteoarthritis

PURPOSE

The aim of this study was to compare the outcomes of tibial fixation with either a cemented or cementless with screw augmentation component in young patients with non-inflammatory arthritis.

METHODS

Ninety-three patients aged 55 or younger with non-inflammatory arthritis were randomized to compare outcomes between cemented tibial fixation (48 patients) and cementless fixation with screw augmentation (45 patients). The femoral component was cementless in both groups. Post-operative evaluation was assessed by the clinical and radiological criteria of The Knee Society and WOMAC questionnaire.

RESULTS

The median follow-up was 6.7 (5-12) years. Significant differences were found for knee score (p = 0.02), range of motion (p = 0.04), and WOMAC score (p = 0.03). In the cemented group, there was one deep wound infection, four tibial aseptic loosening, and one polyethylene wear, all of which were revised. In the cementless group there was one tibial aseptic loosening and one polyethylene wear, both being revised. There was no difference in revision rate, and the cumulative survival at 9-year for aseptic reason was 93.7 % (95 % CI, 82-100 %) in the cementless group and 90.0 % (95 % CI, 80-100 %) in the cemented group (n.s.).

CONCLUSIONS

Cementless total knee arthroplasty was found to be a reliable option in younger patients with osteoarthritis. Although the revision rate and survival were similar in both groups, better clinical outcomes were obtained with cementless tibial components.

Decreasing total joint implant costs and physician specific cost variation through negotiation

Reducing the cost of total joint implants can significantly reduce the cost of an episode of care without affecting the quality. In 2011 we began a program to decrease and standardize the pricing of total joint implants. In the first year of the intervention we preformed 1,090 and 1,022 unilateral total knee and total hip arthroplasties respectively. Based on our volume and pricing data, our institution saved over $2 million during the first year of this intervention. It is clear that our initiative to negotiate lower implant cost with our vendors has lead to a significant reduction in the cost of joint arthroplasties and a reduction in the variability in costs between physicians.

An in vitro comparison of tibial tray cementation using gun pressurization or pulsed lavage

PURPOSE

Aseptic loosening of the tibial component remains a limitation to the highly successful procedure of total knee arthroplasty (TKA). Pulsed lavage improves bone cement penetration and interface strength in tibial tray cementation. This study tested whether pressurized cement application with a cement gun can compensate the use of jet lavage for bone surface preparation.

METHODS

Tibial components were implanted in six pairs of cadaveric tibiae. On one side, pulsed lavage of the tibial bone was combined with finger packing of bone cement; on the other side, syringe lavage and gun cementing was used. Cement penetration into the bone was determined from computed tomography scans, and Interface strength was determined by pull-out testing.

RESULTS

Cement penetration was greater (p = 0.004) and interface strength was higher (p = 0.028) in the pulsed lavage group.

CONCLUSION

Pressurization of cement by gun application could not compensate for the omission of pulsed lavage. Thus, pulsed lavage should be considered a crucial factor in TKA to improve implant fixation, which cannot be compensated for by cement application technique.

Joint registries as continuous surveillance systems: the experience of the Catalan Arthroplasty Register (RACat)

The aim was to present results on prosthesis performance in Catalonia for the period 2005-2010. All publicly funded hospitals submit in an electronic format data on hip and knee arthroplasties: patients' insurance identification number, hospital, joint (hip/knee), type of arthroplasty (primary/revision), side (right/left), date of surgery and prosthesis (manufacturer name and catalogue number). A standard survival analysis based on Kaplan-Meier estimation was carried out. Fifty-two hospitals have sent information to the RACat which has data on 36,951 knee and 26,477 hip arthroplasties. Cumulative prostheses revision risks at 3 years were 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. When compared to other registries a higher risk of revision was observed.

Do refinements to original designs improve outcome of total knee replacement? A retrospective cohort study

Background

Long-term results of the 'classic’ low contact stress (LCS) total knee replacement (TKR) have been satisfactory; nonetheless, design changes have been made which resulted in the 'complete’ LCS TKR. The aim of this study is to compare the 5-year incidence of revision and midterm clinical performance before and after introduction of the 'complete’.

Methods

A retrospective cohort analysis was conducted on 100 primary uncemented TKRs of both designs. At 5-year follow-up, revision and reoperation rates were determined for these 200 TKRs. Knee Society score (KSS), the Oxford Knee score (OKS) and range of motion were determined for 143 TKRs.

Results

In the 'classic’ cohort, 3% of the TKRs were revised compared with 5% in the 'complete’ cohort (p = 0.72).The mean KSS was 134.1 (SD 38.3) in the 'classic’ cohort compared to 135.0 (SD 42.8) in the 'complete’ cohort (p = 0.89). Of the 'complete’ TKRs, 35.2% scored within the lowest quartile of the KSS knee compared to 16.7% of the 'classic’ TKRs (p = 0.01). The OKS was 23.3 (SD 9.3) in the 'classic’ cohort compared to 22.5 (SD 10.1) in the 'complete’ cohort (p = 0.45). More than 5° flexion contracture was only found in four patients in the 'complete’ cohort (p = 0.04).

Conclusions

No statistical difference in revision rate and average scores for midterm clinical performance was observed between the 'classic’ and the 'complete’. However, the 'complete’ cohort had a higher percentage of KSS Knee in the lowest quartile, which suggests a clinical relevant difference compared with the 'classic’. Further investigation in future studies with new designs is needed.

Predictive factors for failure after total knee replacement revision

PURPOSE

We used the Optetrak Condylar Constrained (CCK) implant, a modular and constrained knee implant as replacement for a failed primary arthroplasty, to assess the survivorship, the complications, the clinical, radiological, and functional situation, and the quality of life of those patients in whom a CCK had been implanted in recent years in order to find predictive pre-operative conditions of survival and clinical outcomes.

METHODS

We performed a retrospective study of 125 CCK implanted between 1999 and 2005. The mean follow-up was nine years (range, seven to 13). Mean age was 73.6 years. A total of 78% of the revised TKA were cemented and 66% were CR. We assessed the pre-operative, the operative and the postoperative conditions studying the medical files of all the patients. In order to study the functional and clinical situation we used the Hospital for Special Surgery (HSS) score and the Knee Society score (KSS), both clinical and functional. We analysed all the X-rays using the Knee Society Roentgenographic evaluation. The quality of life was studied using the Oxford knee score (OKS).

RESULTS

The mean results of the KSS clinical and the KSS functional were 68.24 and 63.85, respectively. There were not any conditions associated with poor results of the knees (p > 0.05). The global survival at 24 months was 92.7%, at 60 months 87.8% and at 96 months it was 87.8%. There were some conditions associated with poor survival of the knees, e.g. patients were younger than 70 years old, rheumatic diseases, kidney faliure, tibial tuberosity osteotomy, PS primary arthroplasty, revision before five years and septic loosening.

CONCLUSIONS

Based on these results there are some pre-operative factors that change the survival of the total knee replacement revision.

Comparative outcomes and cost-utility after surgical treatment of focal lumbar spinal stenosis compared with osteoarthritis of the hip or knee--part 1: long-term change in health-related quality of life

BACKGROUND CONTEXT

It is well accepted that total hip and knee arthroplasty (THA/TKA) for osteoarthritis (OA) is associated with reliable and sustained improvements in postoperative health-related quality of life (HRQoL). Although several studies have demonstrated comparable outcomes with THA/TKA after surgical intervention for lumbar spinal stenosis (LSS), the sustainability of the outcome after LSS surgery compared with THA/TKA remains uncertain.

PURPOSE

The primary purpose of this study is to assess whether improvements in HRQoL after surgical management of focal lumbar spinal stenosis (FLSS) with or without spondylolisthesis are sustainable over the long term compared with that of THA/TKA for OA.

STUDY DESIGN

Single-center, retrospective, longitudinal matched cohort study of prospectively collected outcomes, with a minimum of 5-year follow-up (FU).

PATIENT SAMPLE

Patients who had primary one- to two-level spinal decompression with or without instrumented fusion for FLSS and THA/TKA for primary OA.

OUTCOME MEASURES

Postoperative change from baseline to last FU in Short-Form 36 physical component summary (PCS) and mental component summary (MCS) scores among groups was used as the primary outcome measure.

METHODS

An age, sex-matched inception cohort of primary one- to two-level spinal decompression with or without instrumented fusion for FLSS (n=99) was compared with a cohort of primary THA (n=99) and TKA (n=99) for OA and followed for a minimum of 5 years. Linear regression was used for the primary analysis.

RESULTS

Mean (percent) FUs in months were 80.5+16.04 (79%), 94.6+16.62 (92%), and 80.6+16.84 (85%) for the FLSS, THA, and TKA cohorts, respectively, with a range of 5 to 10 years for all three cohorts. The number of patients who have undergone revision including those lost to FU for the FLSS, THA, and TKA cohorts were n=20 (20.2%, same site [n=7] and adjacent segment [n=13]) requiring 27 operations, n=3 (3%, same site) requiring 5 operations, and n=8 (8.1%, same site) requiring 12 operations, respectively (p<.01). The average time to first revision was 56/65/43 months, respectively. Mean postoperative PCS (p<.0001) and MCS (p<.02) scores improved significantly and were durable for all groups at the last FU. The mean changes from baseline PCS/MCS scores to last FU were 8.5/6.4, 12.3/7.0, and 8.3/4.9 for FLSS, THA, and TKA, respectively. Adjusting for baseline age, sex, body mass index, PCS score, and MCS score, there was a strong trend in favor of greater sustained change in the PCS score of THA over FLSS (p=.07) and TKA (p=.08). No difference was noted for change in PCS score between FLSS and TKA (p=.95). No differences were noted for change in MCS score among all three cohorts (p>.1).

CONCLUSIONS

Significant improvements in HRQoL after surgical treatment of FLSS with or without spondylolisthesis and hip and knee OA are sustained for a mean of 7 to 8 years, with a minimum of 5-year FU. Despite a higher revision rate, patients undergoing surgery for FLSS can expect a comparable long-term average improvement in HRQoL from baseline compared with their peers undergoing TKA and to a lesser extent THA.

Comparative outcomes and cost-utility following surgical treatment of focal lumbar spinal stenosis compared with osteoarthritis of the hip or knee: part 2--estimated lifetime incremental cost-utility ratios

BACKGROUND CONTEXT

Although total hip arthroplasty (THA) and total knee arthroplasty (TKA) have been widely accepted as highly cost-effective procedures, spine surgery for the treatment of degenerative conditions does not share the same perception among stakeholders. In particular, the sustainability of the outcome and cost-effectiveness following lumbar spinal stenosis (LSS) surgery compared with THA/TKA remain uncertain.

PURPOSE

The purpose of the study was to estimate the lifetime incremental cost-utility ratios for decompression and decompression with fusion for focal LSS versus THA and TKA for osteoarthritis (OA) from the perspective of the provincial health insurance system (predominantly from the hospital perspective) based on long-term health status data at a median of 5 years after surgical intervention.

STUDY DESIGN/SETTING

An incremental cost-utility analysis from a hospital perspective was based on a single-center, retrospective longitudinal matched cohort study of prospectively collected outcomes and retrospectively collected costs.

PATIENT SAMPLE

Patients who had undergone primary one- to two-level spinal decompression with or without fusion for focal LSS were compared with a matched cohort of patients who had undergone elective THA or TKA for primary OA.

OUTCOME MEASURES

Outcome measures included incremental cost-utility ratio (ICUR) ($/quality adjusted life year [QALY]) determined using perioperative costs (direct and indirect) and Short Form-6D (SF-6D) utility scores converted from the SF-36.

METHODS

Patient outcomes were collected using the SF-36 survey preoperatively and annually for a minimum of 5 years. Utility was modeled over the lifetime and QALYs were determined using the median 5-year health status data. The primary outcome measure, cost per QALY gained, was calculated by estimating the mean incremental lifetime costs and QALYs for each diagnosis group after discounting costs and QALYs at 3%. Sensitivity analyses adjusting for +25% primary and revision surgery cost, +25% revision rate, upper and lower confidence interval utility score, variable inpatient rehabilitation rate for THA/TKA, and discounting at 5% were conducted to determine factors affecting the value of each type of surgery.

RESULTS

At a median of 5 years (4-7 years), follow-up and revision surgery data was attained for 85%-FLSS, 80%-THA, and 75%-THA of the cohorts. The 5-year ICURs were $21,702/QALY for THA; $28,595/QALY for TKA; $12,271/QALY for spinal decompression; and $35,897/QALY for spinal decompression with fusion. The estimated lifetime ICURs using the median 5-year follow-up data were $5,682/QALY for THA; $6,489/QALY for TKA; $2,994/QALY for spinal decompression; and $10,806/QALY for spinal decompression with fusion. The overall spine (decompression alone and decompression and fusion) ICUR was $5,617/QALY. The estimated best- and worst-case lifetime ICURs varied from $1,126/QALY for the best-case (spinal decompression) to $39,323/QALY for the worst case (spinal decompression with fusion).

CONCLUSION

Surgical management of primary OA of the spine, hip, and knee results in durable cost-utility ratios that are well below accepted thresholds for cost-effectiveness. Despite a significantly higher revision rate, the overall surgical management of FLSS for those who have failed medical management results in similar median 5-year and lifetime cost-utility compared with those of THA and TKA for the treatment of OA from the limited perspective of a public health insurance system.

Cementless and cemented total knee arthroplasty in patients younger than fifty five years. Which is better?

PURPOSE

The purpose of this prospective, randomised study was to evaluate long-term clinical results, radiographic findings, complications and revision and survivorship rates in patients <55 years at a minimum of 16 years after undergoing bilateral, sequential, simultaneous, cemented and cementless total knee arthroplasties (TKAs) in the same patients.

METHODS

Bilateral, sequential, simultaneous TKAs were performed in 80 patients (160 knees). There were 63 women and 17 men with a mean age of 54.3 years (range 49-55), who received a cementless prosthesis in one knee and a cemented prosthesis in the other. The mean follow-up was 16.6 years (range 16-17).

RESULTS

At final review, the mean Knee Society (KS) knee scores (95.8 versus 96.9), Western Ontario and McMaster Universities (WOMAC) osteoarthritis (OA) index (25.4 versus 25.9), range of motion (ROM) (125° versus 128°), patient satisfaction (8.1 versus 8.3) and radiological results were similar in both groups. Femoral component survival rate was 100% in both groups at 17 years; at 17 years, the cemented tibial component survival rate was 100% and the cementless tibial component 98.7%. No osteolysis was identified in either group.

CONCLUSION

Long-term results of both cementless and cemented TKAs were encouraging in patients with OA who were <55 years. However, we found no evidence to prove the superiority of cementless over cemented TKAs.

Trabecular metal in total knee arthroplasty associated with higher knee scores: a randomized controlled trial

BACKGROUND

Porous tantalum is an option of cementless fixation for TKA, but there is no randomized comparison with a cemented implant in a mid-term followup.

QUESTIONS/PURPOSES

We asked whether a tibial component fixed by a porous tantalum system might achieve (1) better clinical outcome as reflected by the Knee Society Score (KSS) and WOMAC Osteoarthritis Index, (2) fewer complications and reoperations, and (3) improved radiographic results with respect to aseptic loosening compared with a conventional cemented implant.

METHODS

We randomized 145 patients into two groups, either a porous tantalum cementless tibial component group (Group 1) or cemented conventional tibial component in posterior cruciate retaining TKA group (Group 2). Patients were evaluated preoperatively and 15 days, 6 months, and 5 years after surgery, using the KSS and the WOMAC index. Complications, reoperations, and radiographic failures were tallied.

RESULTS

At 5-year followup the KSS mean was 90.4 (range, 68-100; 95% CI, ± 1.6) for Group 1, and 86.5 (range, 56-99; 95% CI, ± 2.4) for Group 2. The effect size, at 95% CI for the difference between means, was 3.88 ± 2.87. The WOMAC mean was 15.1 (range, 0-51; 95% CI, ± 2.6) for the Group 1, and 19.1 (range, 4-61; 95% CI, ± 2.9) for Group 2. The effect size for WOMAC was -4.0 ± 3.9. There were no differences in the frequency of complications or in aseptic loosening between the two groups.

CONCLUSIONS

Our data suggest there are small differences between the uncemented porous tantalum tibial component and the conventional cemented tibial component. It currently is undetermined whether the differences outweigh the cost of the implant and the results of their long-term performance.

Experimental investigation of the effect of surface roughness on bone-cement-implant shear bond strength

Debonding of cemented bone implants is regarded as a major contributor to complications. The relationship between shear bond strength and surface roughness has been investigated, however there are inconsistencies in the trends reported in different studies. The shear strength between poly(methyl methacrylate) bone-cement and sand blasted cobalt-chromium and titanium alloy surfaces was measured to investigate the relationship between interfacial shear strength and surface topology. Surface roughness was quantified by a power law relationship fitted to Fourier spectra as well as three traditional parameters (arithmetical average roughness (Ra), volume of interdigitation (Rr), and RMS slope (Rdq)). We found that the interfacial shear strength is directly proportional to the exponent of the surfaces power spectra (P2) and Rdq, but not to Ra and Rr. However, Rdq is shown to be critically dependent on sampling frequency, making it sensitive to measurement settings. P2 was found to be a robust measure of the surface roughness being independent of sampling frequency.

Placing a price on medical device innovation: the example of total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is common, effective, and cost-effective. Innovative implants promising reduced long-term failure at increased cost are under continual development. We sought to define the implant cost and performance thresholds under which innovative TKA implants are cost-effective.

METHODS

We performed a cost-effectiveness analysis using a validated, published computer simulation model of knee osteoarthritis. Model inputs were derived using published literature, Medicare claims, and National Health and Nutrition Examination Survey data. We compared projected TKA implant survival, quality-adjusted life expectancy (QALE), lifetime costs, and cost-effectiveness (incremental cost-effectiveness ratios or ICERs) of standard versus innovative TKA implants. We assumed innovative implants offered 5-70% decreased long-term TKA failure rates at costs 20-400% increased above standard implants. We examined the impact of patient age, comorbidity, and potential increases in short-term failure on innovative implant cost-effectiveness.

RESULTS

Implants offering ≥50% decrease in long-term TKA failure at ≤50% increased cost offered ICERs <$100,000 regardless of age or baseline comorbidity. An implant offering a 20% decrease in long-term failure at 50% increased cost provided ICERs <$150,000 per QALY gained only among healthy 50-59-year-olds. Increasing short-term failure, consistent with recent device failures, reduced cost-effectiveness across all groups. Increasing the baseline likelihood of long-term TKA failure among younger, healthier and more active individuals further enhanced innovative implant cost-effectiveness among younger patients.

CONCLUSIONS

Innovative implants must decrease actual TKA failure, not just radiographic wear, by 50-55% or more over standard implants to be broadly cost-effective. Comorbidity and remaining life span significantly affect innovative implant cost-effectiveness and should be considered in the development, approval and implementation of novel technologies, particularly in orthopedics. Model-based evaluations such as this offer valuable, unique insights for evaluating technological innovation in medical devices.

Comparison of cemented and uncemented fixation in total knee arthroplasty

As a result of reading this article, physicians should be able to :1. Understand the rationale behind using uncemented fixation in total knee arthroplasty.2.Discuss the current literature comparing cemented and uncemented total knee arthroplasty3. Describe the value of radiostereographic analysis in assessing implant stability.4. Appreciate the limitations in the available literature advocating 1 mode of fixation in total knee arthroplasty. Total knee arthroplasty performed worldwide uses either cemented, cementless, or hybrid (cementless femur with a cemented tibia) fixation of the components. No recent literature review concerning the outcomes of cemented vs noncemented components has been performed. Noncemented components offer the potential advantage of a biologic interface between the bone and implants, which could demonstrate the greatest advantage in long-term durable fixation in the follow-up of young patients undergoing arthroplasty. Several advances have been made in the backing of the tibial components that have not been available long enough to yield long-term comparative follow-up studies. Short-term radiostereographic analysis studies have yielded differing results. Although long-term, high-quality studies are still needed, material advances in biologic fixation surfaces, such as trabecular metal and hydroxyapatite, may offer promising results for young and active patients undergoing total knee arthroplasty when compared with traditional cemented options.

Cementing techniques for the tibial component in primary total knee replacement

The optimum cementing technique for the tibial component in cemented primary total knee replacement (TKR) remains controversial. The technique of cementing, the volume of cement and the penetration are largely dependent on the operator, and hence large variations can occur. Clinical, experimental and computational studies have been performed, with conflicting results. Early implant migration is an indication of loosening. Aseptic loosening is the most common cause of failure in primary TKR and is the product of several factors. Sufficient penetration of cement has been shown to increase implant stability. This review discusses the relevant literature regarding all aspects of the cementing of the tibial component at primary TKR.

Comparison of cementless and hybrid cemented total knee arthroplasty

Cementless total knee arthroplasty (TKA) implants were designed to provide long-term fixation without the risk of cement-associated complications. The purpose of this study was to evaluate the outcome of titanium-coated cementless implants compared with hybrid TKA implants with a cemented tibial and a cementless femoral component. The authors performed a case-control, single-center study of 120 TKAs performed between 2003 and 2007, including 60 cementless and 60 hybrid cemented TKAs. The authors prospectively analyzed the radiographic and clinical data and the survivorship of the implants at a minimum follow-up of 5 years. Ninety patients who underwent TKA completed the 5-year assessment. Knee Society Scores increased significantly in both groups (P<.001). In both groups, 2 patients underwent revision due to aseptic tibial component loosening, resulting in a 96% implant survival rate. Radiographs showed significantly less radiolucent lines around the tibial baseplate in the cementless group (n=12) than in the hybrid cemented group (n=26) (P=.009).At 6-year mean follow-up, no significant difference existed between the cementless and hybrid cemented tibial components in TKA in terms of clinical and functional results and postoperative complications. The significantly smaller number of radiolucent lines in the cementless group is an indicator of primary stability with the benefit of long-term fixation durability of TKA.

Evidence-based review for patients undergoing elective hip and knee replacement

BACKGROUND

The objective of this study was to evaluate the evidence for different interventions in the preoperative, perioperative and post-operative care for people undergoing elective total hip (THR) and knee (TKR) replacement surgery.

METHOD

A multidisciplinary working group comprising consumers, managers and clinicians from the areas of orthopaedics, rheumatology, aged care and rehabilitation evaluated randomized controlled trials (RCTs) and systematic reviews/meta-analyses concerning aspects of preoperative, perioperative and post-operative clinical care periods for THR/TKR through systematic searching of Medline, Embase, CENTRAL and the Cochrane Database of Systematic Reviews from May 2007 to April 2011. Multiple reviewers determined study eligibility and one or more members extracted primary study findings. The body of evidence were assessed and specific recommendations made according to NHMRC guidelines.

RESULTS

Twenty-five aspects were identified for review. Recommendations for 16 of 25 areas of care were made: impact of waiting, multidisciplinary preparation, preoperative exercise, smoking cessation, interventions for comorbid conditions, predictors of outcome, clinical pathways, implementation of a blood management programme, antibiotic prophylaxis, regional anaesthesia and analgesia, use of a tourniquet in knee replacement, venous thromboembolism prophylaxis, early post-operative cryotherapy, early mobilization and continuous passive motion. In the post-operative period, study heterogeneity across all aspects of care precluded specific recommendations.

CONCLUSIONS

There was a deficiency in the quality of the evidence supporting key aspects of the continuum of care for primary THR/TKR surgery. Consequently, recommendations were limited. Prioritization and funding for research into areas likely to impact clinical practice and patient outcomes after elective joint replacement surgery are the next important steps.

Cementless fixation in total knee arthroplasty: down the boulevard of broken dreams - opposes

In this study we present our experience with four generations of uncemented total knee arthroplasty (TKA) from Smith & Nephew: Tricon M, Tricon LS, Tricon II and Profix, focusing on the failure rates correlating with each design change. Beginning in 1984, 380 Tricon M, 435 Tricon LS, 305 Tricon 2 and 588 Profix were implanted by the senior author. The rate of revision for loosening was 1.1% for the Tricon M, 1.1% for the Tricon LS, 0.5% for the Tricon 2 with a HA coated tibial component, and 1.3% for the Profix TKA. No loosening of the femoral component was seen with the Tricon M, Tricon LS or Tricon 2, with no loosening seen of the tibial component with the Profix TKA. Regarding revision for wear, the incidence was 13.1% for the Tricon M, 6.6% for the Tricon LS, 2.3% for the Tricon 2, and 0% for the Profix. These results demonstrate that improvements in the design of uncemented components, including increased polyethylene thickness, improved polyethylene quality, and the introduction of hydroxyapatite coating, has improved the outcomes of uncemented TKA over time.

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.