Mid-term outcomes of primary constrained condylar knee arthroplasty for severe knee deformity

Aseptic midterm survival rates between different cemented tibial stem designs in hinged total knee arthroplasty: a 6-year evaluation from the German Arthroplasty Registry

INTRODUCTION

The rate of revision TKA and thus the use of hinged implants (HI) steadily rises. Aseptic loosening lies on the top of the failure patterns. However, no evidence exists until now based on national scale high-caseloads that analyzes the impact of cemented HI stem-design on aseptic survival rates.

METHODS

Data on aseptic HI-revisions with full-cemented tibia-stems were conducted from the German Arthroplasty Registry. Cases were divided in primary HI (PHI) and HI used in revision operations (RHI). Endpoint was a new revision following either a PHI or an RHI. The impact of stem conicity (conical vs. cylindrical), diameter (≤ 13 mm vs. > 13 mm), length (≤ 90 mm vs. > 90 mm) and offset on the 6-Year-Cumulative-Aseptic-Revision-Rate (6Y-CARR) was estimated via Kaplan-Meier curve and compared between groups via Log-Rank-Tests.

RESULTS

3953 PHI and 2032 RHI fulfilled inclusion-criteria. Stem conicity had no impact on 6Y-CARR (p = 0.08 and p = 0.8). Diameter > 13 mm hat an impact on PHI (p = 0.05) with lower 6Y-CARR but not on RHI (p = 0.2). Length > 90 mm showed significantly worst 6Y-CARR in PHI (p = 0.0001) but not in RHI (p = 0.3). Offset-stems showed significantly better 6Y-CARR in PHI (p = 0.04), but not in RHI (p = 0.7).

CONCLUSION

There was no significant impact of the cemented tibia-stem conicity on 6Y-CARR, neither in PHI nor in RHI. The effect of length, diameter and offset on the 6Y-CARR observed in the PHI, was not detectable in the more complex RHI-cases reflecting its limited clinical relevance by itself in more multifactorial backgrounds. Therefore, results must be interpreted with caution due to considerable system-effects and different utilization-scenarios.

Clinical outcome and survival rate of condylar constrained knee prosthesis in revision total knee arthroplasty: an average nine point six year follow-up

PURPOSE

Condylar constrained knee prostheses (CCK) are increasingly used in revision total knee arthroplasty (rTKA), but the clinical effectiveness and long-term survival remain a debate. The purpose of this study is to report the long-term clinical and radiographic outcome, implant survival rate, and surgical safety of revision total knee arthroplasty with condylar constrained knee prosthesis.

METHODS

A retrospective cohort study was performed on patients undergoing rTKA with CCK. The cases who received rTKA with CCK from January 2005 to January 2022 were selected. The duration of operation, the estimated perioperative blood loss, and the intraoperative blood transfusion rate were recorded to evaluate surgical safety. The pain visual analog scale (VAS), range of motion (ROM), the Hospital for Special Surgery (HSS) score, the Knee Society Score (KSS), the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and the Oxford knee score (OKS) was recorded to assess clinical outcome. Standard anteroposterior, lateral, skyline and long-standing AP radiographs of the lower limbs were conducted to assess radiographic outcome. Implant survival was analyzed by Kaplan-Meier survival estimates.

RESULTS

Fifty-five cases were followed up for an average of 9.6 years (1-18 years), including 16 males and 38 females, with an average age of 66 and an average BMI of 26.9 kg/m2. The  main reasons for revision were periprosthetic infection (32 knees, 58.2%) and aseptic loosening (13 knees, 23.6%). The duration of operation was 149 ± 56.2 min. The perioperative blood loss was 973.6 ± 421.6 ml. At the last follow-up, VAS (8.0 ± 1.1 to 1.3 ± 1.4), ROM (82.7° ± 26.1° to 108.4° ± 11.8°), HSS (45.0 ± 10.4 to 85.3 ± 8.6), KSKS (38.4 ± 12.1 to 88.5 ± 12.0), KSFS (19.6 ± 12.9 to 68.8 ± 15.1), WOMAC (67.9 ± 12.5 to 14.4 ± 9.5), and OKS (9.9 ± 4.2 to 41.6 ± 7.7) were significantly improved (P < 0.001). A total of five complications were observed, all of which were periprosthetic infection. Non-progressive radiolucent lines were observed in 26 knees (47.3%). The 10-year survival rate for no operation was 96.0%. The ten year survival rate for no revision was 98.0%.

CONCLUSION

The use of CCK prosthesis for rTKA can achieve good long-term efficacy and prosthesis survival.

Use of semi-constrained total knee arthroplasty in gonarthrosis with collateral ligament insufficiency: Clinical and functional outcomes

INTRODUCTION

Achieving stability in total knee arthroplasty (TKA) is crucial for long-term implant survival. In cases of severe deformity or ligament laxity, constrained implants may be required. Traditionally, increasing constraint involved intramedullary stems. However, there are intermediary alternatives, including employing a constrained polyethylene insert without stems, thereby avoiding complications related to them. The study aims to evaluate our experience with a non-modular constrained (NMC) implant in primary TKA.

MATERIAL AND METHODS

We conducted a retrospective review of the clinical and radiographic outcomes of 108 non-stemmed primary TKAs performed at our institution between 2013 and 2021 in patients with at least 10° deformity or 10mm ligament laxity. Data included demographics, preoperative and postoperative deformities, clinical outcomes and revision rates.

RESULTS

A total of 103 patients (108 knees) with a mean age of 74 were followed up for a minimum of 2 years. The mean postoperative range of motion was 105°/0°. The median Oxford Knee Score, Knee Society Score and Knee Society Function Score were 43.5, 92 and 90, respectively. 17 knees had varus deformity (mean tibiofemoral angle of 2.7°), and 87 knees had excessive valgus deformity (mean tibiofemoral angle of 15.1°). The remaining 4 knees had a neutral alignment. The mean postoperative tibiofemoral angle was 6.8°. The overall revision rate was 6.5% (7 patients): 3 deep periprosthetic infections, 2 patellar dislocations, 1 stiffness and 1 aseptic loosening.

CONCLUSION

Our experience demonstrates favorable mid-term outcomes with the NMC implant, providing a safe alternative to stemmed implants in primary TKA, particularly in cases of severe deformity or ligament laxity.

Primary constrained condylar knee arthroplasty in severe varus deformity: a prospective 5-year functional follow-up study in Iraqi patients

PURPOSE

The outcomes of the constrained condylar knee (CCK) implant used during primary total knee arthroplasty (TKA) in knees with severe varus in patients from low- and middle-income countries (LMICs) such as Iraq are not known. Hence, this study aimed to analyze and report the functional outcome of CCK TKA in patients with severe varus deformities at the end of 5 years in Iraqi patients.

METHODS

In this prospective study, pre- and post-operative (at the end of 5 years) clinical outcome using Knee Society Score (KSS) and radiological deformity using hip-knee-ankle (HKA) angle was analyzed in 76 CCK TKAs (20 bilateral and 36 unilateral TKAs) performed in 56 patients with severe varus deformity (> 15°).

RESULTS

At a mean follow-up of 60.3 months (range 60-68 months), the mean preoperative KSS knee score of 6.6 ± 4.5 improved significantly (p < 0.0001) to 87.2 ± 6.6 and the mean preoperative KSS function score of 7.1 ± 6.4 improved significantly (p < 0.0001) to 70.4 ± 7.8. The function score was good to excellent in 64.3% (36 patients), fair in 28.5% (16 patients), and poor in 7.1% (4 patients) at the end of 5 years. The mean preoperative HKA angle significantly improved (p < 0.001) from 25.5° ± 6° varus (range 17°-37°) to 3° ± 2.5° varus (range 0°-7.5°) at final follow-up.

CONCLUSION

The CCK implant significantly improved pain and function in patients with severe varus deformity at the end of 5 years. The CCK implant is a good option during primary TKA in severe varus knees in patients from LMICs and can help achieve clinical outcomes similar to patients from high-income countries.

A Comparison Between Unstemmed and Stemmed Constrained Condylar Knee Prostheses in Primary Total Knee Arthroplasty: A Propensity Score-Matched Analysis

Objective

To compare and analyze the clinical outcomes between unstemmed and stemmed constrained condylar knees (CCK) in complex primary total knee arthroplasty (TKA) in terms of implant survivorship, change in outcome evaluations, and complications.

Methods

We reviewed 156 consecutive patients who received primary TKA using PFC®SIGMA®TC3 (TC3) of constrained condylar design between January 2009 and January 2017 at our institution. After removing patients who met exclusion criteria, 25 patients were identified as unstemmed TC3 cases and 81 as stemmed TC3 cases. Propensity score matching was used to select 25 stemmed cases as a control group for the unstemmed group with comparable preoperative conditions including preoperative demographics, preoperative diagnosis, preoperative range of motion, main reason to use TC3, ASA score (American Society of Anesthesiologists), and follow‐up duration. Preoperative and postoperative clinical evaluations including Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, the 12‐Item Short‐Form Health Survey (SF‐12), and the range of motion (ROM) were obtained and compared. The instability, periprosthetic fracture, radiolucent lines, polyethylene wear, and heterotrophic ossification were assessed according to the anteroposterior and lateral radiographs of the knee. The complications and implant survivorship between the two groups were also recorded and compared.

Results

3After the index surgery, both groups showed substantial improvement in KSS (knee and function), HSS score, SF‐12, and ROM compared with baseline. There was no significant difference in the mean KSS scores (knee and function), HSS score, SF‐12, and ROM between the unstemmed and stemmed group postoperatively. No statistically significant difference was found in the overall complication rate between the two groups. The overall Kaplan–Meier survivorship was 98.0% (95% confidence interval 94.1%–100.0%) at 7 years. No significant difference was found in the survival rate between the unstemmed group (100.0%) and the stemmed group (96.0%) at 7 years (log rank, P = 0.317). The mean duration of follow‐up was 7.0 years for unstemmed group and 7.7 years for stemmed group.

Conclusions

In patients with adequate bone stock receiving complex primary TKA, unstemmed CCK could achieve similar clinical outcomes at mid‐term follow‐up as stemmed CCK.

Staged Bilateral Total Knee Arthroplasty for Neglected Blount Disease Using a Gap Balancing Technique

Blount disease is an acquired, asymmetrical disorder of proximal tibial growth that results in a complex three-dimensional proximal tibial deformity, with tibial varus being the dominating feature. Although the exact pathophysiology is unknown, Blount disease is separated into 2 clinical variants, infantile and adolescent, based on the onset of symptoms occurring before or after the age of 10 years. If recognized and treated early, affected patients generally have a favorable prognosis; however, if neglected, it can lead to progressive malalignment and premature osteoarthritis. We present a patient with bilateral neglected Blount disease who underwent successful bilateral total knee arthroplasty performed in a staged fashion using a gap balancing technique with constrained condylar knee implants.

Is varus-valgus constraint a reliable option in complex primary total knee arthroplasty? A systematic review

Purpose

Knee instability is considered one of the most frequent cause of failure after primary total knee arthroplasty (TKA). In order to address intraoperative instability, varus-valgus constrained knee implants (VVC) are increasingly utilized in primary TKA. Despite an increased risk of mechanical failure, short to mid-term results seem to be encouraging, but long-term results are still lacking.

Methods

A systematic review of prospective and retrospective studies that reported clinical outcomes of patients with VVC systems in primary TKAs between 1990 and 2020 was performed.

Results

In all, 28 articles met our inclusion criteria. A total of 2798 VVC implants were used in primary TKA. The all-cause revision-free survivorship was 95.2% at a mean follow-up of 7 years. Infection and aseptic loosening were the most common reasons for reoperation with an incidence of 1.8% and 1.7%, respectively. Overall complication rate was 9.6%, the most common complications were knee stiffness and infection with an incidence of 2.8% and 2.5%, respectively.

Conclusions

VVC implants in primary TKA are associated with improved functional outcomes and good mid-term survivorship, comparable to lower level of constraint implants. Non-modular stemless seem to be reliable implants at mid-term follow-up. However, given the lack data coming from long-term studies, VVC implants should be used cautiously in primary TKA.

Total knee arthroplasty in valgus knee deformity: is it still a challenge in 2021?

Total knee arthroplasty in valgus knee deformities continues to be a challenge for a surgeon. Approximately 10% of patients who undergo total knee arthroplasty have a valgus deformity. While performing total knee arthroplasty in a severe valgus knee, one should aware with the technical aspects of surgical exposure, bone cuts of the distal femur and proximal tibia, medial and lateral ligament balancing, flexion and extension gap balancing, creating an appropriate tibiofemoral joint line, balancing the patellofemoral joint, preserving peroneal nerve function, and selection of the implant regarding constraint. Restoration of neutral mechanical axis and correct ligament balance are important factors for stability and longevity of the prosthesis and for good functional outcome. Thus, our review aims to provide step by step comprehensive knowledge about different surgical techniques for the correction of severe valgus deformity in total knee arthroplasty.

Satisfactory mid-term outcomes of condylar-constrained knee implants in primary total knee arthroplasty: clinical and radiological follow-up

Background

The purpose of this study was to evaluate (1) the reoperation rates and survivorship for septic and aseptic causes, (2) radiographic outcomes, and (3) clinical outcomes of condylar-constrained knee (CCK) implants used in primary total knee arthroplasty (TKA) with severe coronal deformity and/or intraoperative instability.

Materials and methods

A consecutive series of CCK implants in primary TKA was retrospectively evaluated in patients with severe coronal deformities. Forty-nine patients (54 knees) were included with a mean follow-up of 9 years (range 6–12). All patients were treated with a single-design, second-generation CCK implant. The primary diagnosis was osteoarthritis in 36 knees, post-traumatic arthritis in 7 knees, and rheumatoid arthritis in 4 knees. Preoperatively, standing femorotibial alignment was varus in 22 knees and valgus in 20 knees.

Results

At a mean follow-up of 9 years, overall survivorship was 93.6%. Two knees (4.3%) required revision for periprosthetic joint infection. One knee (2.1%) required subsequent arthroscopy due to patellar clunk syndrome. At final follow-up, no evidence of loosening or migration of any implant was reported, and the mean Knee Society knee scores improved from 43 to 86 points (p < 0.001). The mean Knee Society function scores improved to 59 points (p < 0.001). The average flexion contracture improved from 7° preoperatively to 2° postoperatively and the average flexion from 98° to 110°. No knees reported varus–valgus instability in flexion or extension.

Conclusion

CCK implants in primary TKA with major coronal deformities and/or intraoperative instability provide good midterm survivorship, comparable with less constrained implants. In specific cases, CCK implants can be considered a viable option with good clinical and radiographic outcomes. However, a higher degree of constraint should be used cautiously, leaving the first choice to less constrained implants.

Level of evidence Therapeutic study, level IV.

Varus-Valgus Constraint in Primary Total Knee Arthroplasty: A Short-Term Solution but Will It Last?

BACKGROUND

Prostheses with varus-valgus constraint (VVC) are increasingly utilized in primary total knee arthroplasty (TKA) to address coronal malalignment and instability though little is known regarding the association between added constraint and aseptic loosening. We sought to systematically review the literature for reports of VVC in primary TKA and meta-analyze clinical results and implant survival.

METHODS

PubMed was searched using broad terms to identify articles reporting VVC in primary TKA. Any article reporting clinical or survival outcomes was included. Clinical scores, close to 2 years postoperatively were converted to standardized mean differences, and the latest survival estimates were weighted using the inverse of their variance and meta-analyzed.

RESULTS

Three hundred ninety-two search results were reviewed identifying 30 relevant articles reporting on 3620 knees in total. The estimate for the improvement in clinical scores postoperatively was 3.1 standard deviations (95% confidence interval 2.6-3.6). The estimate for implant revision slowly increased from 1% at 2 years to 2% at 6 years and then began to increase more rapidly beyond this point. The estimated revision rate was 9% by 12 years and 28% by 20 years. This revision rate estimate was stable with and without the inclusion of outlying studies.

CONCLUSION

VVC in primary TKA is associated with significant clinical improvement without significant risk of early failure. Meta-regression estimates raise concerns for significant revision risk with extended follow-up, especially beyond 5 years. In the absence of new data, VVC should continue to be used cautiously in the primary TKA.

Good clinical and radiological results of total knee arthroplasty using varus valgus constrained or rotating hinge implants in ligamentous laxity

PURPOSE

The optimal degree of constraint of a total knee arthroplasty for treatment of knee osteoarthritis with ligamentous laxity is under debate. While varus valgus constrained knees require a minimum level of ligamentous stability, rotating hinge knees can even be implanted if the collateral ligaments have been lost completely. It seems plausible that joint kinematics are determined by implant design in rotating hinge knees, whereas varus valgus constrained knees may be influenced by remaining stabilizers. This may result in more predictable clinical results of hinge knees. The hypothesis of the present study, therefore, was that stability and clinical outcome are better after total knee arthroplasty using rotating hinge knees than after using varus valgus constrained knees.

METHODS

All patients who were treated using a mobile-bearing varus valgus constrained knee or a rotating hinge knee for treatment of end-stage osteoarthritis and ligamentous laxity were included. At follow-up, clinical scores were determined (WOMAC, VAS, KSS, FJS, Lysholm). Furthermore, body mass index, operating time, and postoperative complications were documented. Whole leg radiographs as well as patella axial radiographs were analyzed for implant alignment and patella tracking.

RESULTS

Eighty-five patients were included in this retrospective study. Both groups showed an average range of motion of 113°. No significant difference between the two groups was observed for any of the scores recorded. In the rotating hinge knee group, a more precise tibia positioning in relation to the mechanical axis but also a significant lateralisation and tilting of the patella were seen, compared with the varus valgus constrained knee group.

CONCLUSIONS

Rotating hinge knees did not perform better than mobile-bearing varus valgus constrained knees clinically. Both prosthesis types showed equally good clinical outcomes with regard to stability, mobility, satisfaction, pain and operating time.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Mid-term clinical outcome of constrained condylar knee prosthesis for patients with rheumatoid arthritis

Objectives: This study retrospectively investigated the mid-term outcome of Legacy constrained condylar knee (LCCK) prosthesis in patients with rheumatoid arthritis (RA) having severe varus/valgus deformity, instability, and/or bone loss. Methods: Between January 2000 and December 2015, LCCK prostheses had been performed in 32 knees of 25 patients with RA, and 23 knees of 17 patients of the postoperative follow-up minimum 2 years were analyzed in this study (Primary: 14 knees, Revision: 9 knees). The average of follow-up duration was 6.9 ± 2.7 years, all were female, and the average of age and RA duration at the surgery was 59.0 ± 9.5 years and 26.6 ± 13.5 years, respectively. Clinical result was analyzed by Knee Society Score (KSS) knee and function at preoperative time and final visit. Imaging outcome was investigated by femoral tibial angle (FTA), four component alignment angles, and radiolucent line at pre-/postoperative time. Results: KSS knee/function scores and radiographic FTAs were improved after operation. Radiolucent lines around components were seen in 17 knees (73.9%), of which only one knee (4.3%) has shown aseptic loosening. The seven-year Kaplan-Meier survivorship analysis resulted in 91.7%. Conclusion: LCCK prosthesis in RA patients was achieved to the excellent mid-term clinical and radiographic result.

Clinical and Functional Outcomes: Primary Constrained Condylar Knee Arthroplasty Compared With Posterior Stabilized Knee Arthroplasty

Primary constrained condylar knee arthroplasty does not affect clinical and functional outcomes at 2 years when compared with posterior stabilized knee arthroplasty.

Introduction:

Constrained condylar knee (CCK) prostheses are commonly used in difficult primary total knee arthroplasty and revision total knee arthroplasty. We postulate that the use of CCK prostheses in primary knee arthroplasty may result in decreased range of motion but with better patient-reported functional scores compared with primary posterior stabilized (PS) knee prostheses because of increased varus and valgus stability from increased constraint.

Methods:

We conducted a case-control study using prospectively collected data on functional outcome scores and range of motion preoperatively and at 6 months and at 2 years. Thirty-eight patients with primary CCK arthroplasty were matched with 38 patients with primary PS knee arthroplasty treated by a single surgeon. Institutional review board approval was obtained. Analysis was done using the independent t-test.

Results:

Total 76 patients with 61 (80.3%) female patients, 30 (39.5%) left knees, and 9 (11.8%) valgus knees. There was no significant difference in preoperative age (CCK arthroplasty 70.7 ± 6.0 years versus PS knee arthroplasty 68.5 ± 5.2 years; P < 0.085), body mass index (27.2 ± 4.4 versus 26.3 ± 5.2; P < 0.44), Oxford Knee Score (35.8 ± 7.8 versus 36.0 ± 7.6; P < 0.92), and Medical Outcomes Study 12-Item Short Form (SF-36) scores and knee extension (8.0° ± 6.7° versus 7.7° ± 7.6°; P < 0.84). There was no significant difference in preoperative knee flexion (106.0° ± 22.9° versus 117.3° ± 20.1°; P < 0.026). There was no significant difference in 6-month knee extension (4.5° ± 6.8° versus 4.1° ± 4.5°; P < 0.80), knee flexion (110.5° ± 15.8° versus 110.9° ± 15.5°; P < 0.92), Oxford Knee Score (18.9° ± 3.4° versus 20.1° ± 5.3°; P < 0.27), and SF-36 scores. There was no significant difference in 2-year knee extension (1.8° ± 5.7° versus 1.5° ± 4.0°; P < 0.82), knee flexion (111.3° ± 13.6° versus 115.0° ± 16.5°; P < 0.30), Oxford Knee Score (18.5° ± 3.7° versus 18.2° ± 4.2°; P < 0.77), and SF-36 scores.

Conclusion:

The use of CCK prostheses in primary knee arthroplasty gives similar clinical and functional outcomes at 2 years as those of PS knee prostheses, despite increased constraint.

Coronal alignment predicts the use of semi-constrained implants in contemporary total knee arthroplasty

BACKGROUND

Semi-constrained, or varus-valgus constrained, implants are occasionally necessary to achieve stability in primary total knee arthroplasty (TKA). However, outcomes with these implants are largely unknown. Therefore, the primary goals of this study were to determine 1) can we identify preoperatively which patients might require a semi-constrained implant and 2) are there any clinical and or radiographic differences for those that require a semi-constrained implant?

METHODS

A multicenter retrospective study was performed to retrospectively review patients that had a Stryker Triathlon (Kalamazoo, MI) TKA with a Total Stabilized (TS) tibial insert (n=75). This TS cohort was subsequently matched 1:1 based on age, gender, and BMI to a cohort of patients with the same primary TKA design with a PS insert (n=75). Preoperative and postoperative radiographic and clinical data were compared between the two groups.

RESULTS

Preoperatively, the TS cohort had significantly greater varus (9.72 vs. 3.48; p=0.0001) and valgus (14.1 vs. 7.57; p=0.0001) deformity. Post-operatively, there were no statistically significant differences in revisions (p=1), reoperations (p=1), or complications (p=1). Mean clinical and radiographic follow-ups were equivalent between groups (25.5 vs. 25.8months, p=0.8851).

CONCLUSION

As suspected, use of a semi-constrained insert to achieve intraoperative coronal stability was most predicted by preoperative coronal deformity (either varus or valgus). Longer follow-up and larger patient cohorts are necessary to determine.

Condylar constrained system in primary total knee replacement: our experience and literature review

BACKGROUND

Constrained condylar knee (CCK) prosthesis are common used for revision surgery but can also help surgeons to improve implant stability in primary knee arthroplasty, in fact in severe knee arthrosis with serious deformity associated with a significant instability a more constrained articulation is required. With introduction of second generation of semi-constrained prosthesis, rate of complication is real decreased and a good survival rate and functional score results is showed. In this paper we write about our experience using CCK in primary knee arthroplasty.

METHODS

Between January 2012 and December 2015, 28 second-generation semi-constrained knee arthroplasties were performed as a first implant. Two different types of implants were used: 10 constrained condylar knee (CCK Zimmer) and 18 TC3 (DePuy Johnson & Johnson). All patients were over 75 years old (mean 81.75) with a severe deformity and clinical evaluations at 2-, 6-, 12-month after surgery and every year performed. X-rays at 6, 12 months and then annually was planned with an average follow-up of 31.28 (range 6-48) months.

RESULTS

No patients were lost during the follow-up. The mean functional knee society score (KSS) improved from 30 points preoperatively to 92.1 points at the last follow-up. All patients recovered full extension during follow-up and no radiolucent lines were showed at X-ray control. There were no deep infections or peri-prosthetic fractures.

CONCLUSIONS

Second generation semi-constrained knee prosthesis represent safe and practical treatment in primary total knee arthroplasty (TKA) in case of severe deformity that can't be managed with accurate soft tissue release, especially in elderly patients.