Complex primary and revision total knee arthroplasty using the condylar constrained prosthesis: an average 5-year follow-up

Long-term results (after a mean 11.3years, and up to 22years, of follow-up) of the Legacy Constrained Condylar Knee (LCCK™) in primary total knee arthroplasty

INTRODUCTION

The use of a sliding prosthesis in total knee arthroplasty (TKA) with increased stress is an intermediate solution in primary surgery, between posteriorly stabilized prostheses and hinged prostheses, in cases of ligamentous laxity and/or loss of bone substance. Favorable results have been reported in the medium term but to our knowledge, this type of prosthesis has not been evaluated in Europe beyond 10 years of follow-up. We therefore conducted a retrospective study in order to carry out: 1) the study of the survival of the Legacy Constrained Condylar Knee (LCCK™) prosthesis in primary surgery, 2) the analysis of complications, functional scores and radiographic data, 3) the analysis of the link between the diaphyseal filling rate and prosthetic loosening.

HYPOTHESIS

The LCCK™ sliding prosthesis with increased constraint has equivalent long-term survival and clinical results to standard posteriorly stabilized TKA and superior to hinged TKA.

MATERIAL AND METHOD

A retrospective series of 141 LCCK™ implanted in 134 patients between 1997 and 2010 was analyzed. Survival was assessed with censoring through an evaluation of partial or total revision of the implants. The functional results were evaluated using the IKS and Oxford 12 scores. Data regarding the Canal Fill Ratio (CFR) and the presence of pathological periprosthetic lines were also collected.

RESULTS

The average follow-up was 11.3±5.3years with a maximum follow-up of 22.7years. Survival at 20years was 90.8% [95% CI: 83.7-95.7]. The rate of early complications was 13.5% (19/141), predominantly comprised of venous thrombosis (6/141), hematomas (3/141 including two requiring surgical drainage), stiffness (3/141) and early infections (3/141). The rate of late complications was 17% (24/141), led by stiffness (4.4%; 6/141), infections (2.9%; 4/141) and hardware failure (2. 2%; 3/141). Ten of the 141 patients (7.1%) had LCCK failure, including 3 (2.1%) for stiffness, 3 (2.1%) for hardware failure, 2 (1.4%) for infection, 1 (0.7%) for laxity and 1 (0.7%) for a periprosthetic fracture. No aseptic loosening was found. The total IKS score went from 65 [0-116] to 143 [79-200] at follow-up, the IKS knee score went from 30 [0-66] to 85 [44-100], and the IKS function score went from 35 [0-70] to 57 [0-100]. The Oxford score went from 14 [2-25] to 34 [15-48] at follow-up. Only two patients (1.4%) presented with a partial periprosthetic line. The tibial CFR was 0.81 and the femoral CFR was 0.76. The influence of the CFR could not be analyzed due to the absence of loosening.

DISCUSSION

The LCCK™ prosthesis in primary surgery has good medium-term survival, a significant improvement in functional scores and a complication rate comparable to posteriorly stabilized prostheses. The complication rate is lower than that of hinged prostheses.

LEVEL OF EVIDENCE

IV; single-center retrospective study.

Treatment of Medial Collateral Ligament Injury During Total Knee Arthroplasty With Internal Suture Brace Augmentation: A Cadaveric and Biomechanical Study

Intraoperative medial collateral ligament (MCL) injury during total knee arthroplasty (TKA) is a serious complication. External bracing and/or conversion to a constrained implant has previously been studied. The technique of using an internal high-strength suture brace to augment an MCL repair has been evaluated in the nonarthroplasty patient and could provide an alternate solution. The goal of this study was to determine whether MCL repair with internal suture bracing restores stability of the implanted knee joint. A robotic simulator completed laxity testing on 5 cadaveric knee specimens in 4 sequential phases: (1) intact knee, (2) after implantation with TKA, (3) after sectioning of the MCL, and (4) after MCL repair with suture brace augmentation. Laxity was compared between the different test phases throughout range of motion. Subsequently, the internal brace was tested to failure under valgus load. The MCL repair with internal bracing was effective at restoring laxity in varus-valgus, internal-external, and medial-lateral degrees of freedom through midflexion, with limited support at deeper flexion angles and in anterior-posterior laxity. Rotational laxity was not significantly different than intact knee laxity. Generally, medial-lateral translations were less and anterior-posterior translations were greater and were significantly different at 30° to 45° and 90°, respectively. The mean failure moment was 46.4±9.1 Nm, with the primary mode of failure being MCL repair. Primary MCL repair with internal bracing using a high-strength suture augment showed the potential to provide adequate stability and strength to correct MCL incompetence in TKA without the use of an external knee brace or constrained implants. [Orthopedics. 2022;45(5):e269-e275.].

Meniscus Graft Augmentation for a Midsubstance Tear of the Medial Collateral Ligament during Total Knee Arthroplasty

Multiple surgical techniques exist to repair iatrogenic medial collateral ligament (MCL) injury during total knee arthroplasty (TKA). The objective of the study is to confirm the clinical effectiveness of meniscus transfer for treatment of iatrogenic MCL midsubstance transection in which remaining MCL is of poor quality, and there is a persistent gap between both ligament ends during TKA. From January 2015 to November 2019, we treated 11 patients with MCL injuries of 882 primary TKAs by meniscus transfer. Another 24 primary TKAs were recruited as a control group. The two groups of patients were comparable for age, gender, body mass index (BMI), Knee Society scoring (KSS), knee function score (KFS), and type of prosthesis comparison without significant difference (p > 0.05). We reviewed the patient's stability, as well as objective measures such as KSS and KFS scores, physical examinations, and radiographs. No patient of either group reported impaired wound healing, joint instability on physical examination, pain, radiographic changes, signs of loosening, and other complications. At the final follow-up, there was no significant difference in terms of KSS (p = 0.780) and KFS (p = 0.612) between the injury group and control group at last follow-up. X-ray image review showed no prosthesis loosening or subsidence for both groups. Based on these results, we are cautiously optimistic that midsubstance transections in which the quality of remaining tendon is weak, there is suspicion of stretching, or there is a persistent gap between both ligament ends that can be reconstructed with meniscus autograft transfer augmentation and an unconstrained implant.

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.

Traumatic Lateral Knee Dislocation of a Well-Functioning Total Knee Arthroplasty: A Case of Medial Collateral Ligament Rupture

Tibiofemoral dislocation can be a devastating complication after total knee arthroplasty. Much of the literature on tibiofemoral dislocations state they result from iatrogenic causes, with a very limited number of case reports on traumatic dislocation. Most of the time, these cases will require surgical revision and increased constraint to treat the inherent instability. In addition, collateral ligament disruption increases the complexity of the treatment algorithm for these patients. We report the case of a lateral tibiofemoral total knee arthroplasty dislocation with associated medial collateral ligament injury treated successfully without surgical interventions.

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.

Options and limitations of implant constraint

With an ever-increasing number of revisions, the surgeons will be faced with the dilemma of choosing the right implant for the revision knee. The soft tissue viability governs the choice of an implant at the time of revision. The selection ranges from the cruciate-retaining to the rotating/fixed hinge implants. The surgeon needs to plan preoperatively, but usually, the final decisions are made intraoperative. As determining the amount of constraint necessary can be challenging, we have tried to lay down a few pointers, which would help to make that choice. The posterior stabilized implants can manage most revision knees; in certain situations where they cannot accommodate the flexion-extension gap imbalance, a varus-valgus constrained implant should be used. The rotating hinge implants are used for severe instabilities or loss of soft tissue or bone around the knee. The use of a higher constraint implant has its consequences like reduced life span and reduced function. Thus it is crucial to use the least amount of constraint as necessary - however, as much as required.

Outcomes of Stemmed versus Un-Stemmed Varus-Valgus Constrained Components in Primary Total Knee Arthroplasty

Purpose

The necessity of stemmed components when performing a varus-valgus constrained (VVC) primary total knee arthroplasty (TKA) is unclear. The purpose of this study is to compare the outcomes of primary VVC TKA with and without stems at a minimum of two years.

Methods

Patients in our prospectively collected database with primary VVC TKAs were identified. Patient demographics, prosthesis data, time in vivo, characteristics of revision, and radiographs and PROMs were compared between the stemmed and un-stemmed cohorts.

Results

Sixty-five patients with 69 primary VVC TKAs were identified; 17 were implanted with stems and 52 without stems. Five of the stemmed TKAs (5/17) required revision at 15.1 years, while only one of the un-stemmed TKA (1/52) required a revision at 21.6 years (p=0.003) for aseptic loosening. Of the 5 stemmed TKAs requiring revision, 3 were for aseptic loosening and 2 were for PPJI. The un-stemmed cohort had a significantly higher final total KSS (p=0.048).

Conclusion

There was no increase in aseptic loosening or revision surgery in patients with non-stemmed primary VVC TKA compared to those with stemmed VVC TKA at mid-term follow-up. Utilizing non-stemmed TKA with VVC in appropriate cases is safe and may reduce cost, shorten operative time, and preserve bone-stock.

No difference in failure rates or clinical outcomes between non-stemmed constrained condylar prostheses and posterior-stabilized prostheses for primary total knee arthroplasty

PURPOSE

There has been an increase in the use of unlinked constrained condylar knee (CCK) prostheses in primary total knee arthroplasty (TKA) for cases with significant deformities that cannot be adequately balanced in flexion and extension. However, the literature on its outcomes is limited. The goal of this study is to evaluate whether there are any clinic or radiographic outcome differences for a primary, non-stemmed, unlinked constrained TKA as compared to a control group of posterior-stabilized (PS) TKA using the same implant design.

METHODS

Clinical and radiographic outcome measures for 404 cemented, non-stemmed, primary TKAs performed by two surgeons at the same institution were retrospectively reviewed. All patients underwent primary, non-stemmed components; 241 used CCK inserts and 163 used PS inserts. Preoperative deformity, knee society scores (KSS), range-of-motion (ROM), radiographic data and revision rates were compared between the CCK and PS groups.

RESULTS

Both groups had comparable demographics and preoperative ROM and KSS. At similar mean follow-up times (6.1 ± 1.0 years for the CCK group and 6.3 ± 1.2 years for the PS group), no significant difference was found in ROM, KSS or radiographic outcomes. Revision rates were higher for the CCK group (2%) as compared to the HF-PS (0.6%) group (n.s).

CONCLUSIONS

The particular design of cemented, primary, non-stemmed, unlinked CCK-TKA examined in this study provided similar clinical and radiographic outcomes to that of PS-TKA at midterm follow-up.

LEVEL OF EVIDENCE

III.

Tightening medial collateral ligament during total knee arthroplasty for patients with fixed valgus deformity: A novel technique

BACKGROUND

This study aimed to explore a new surgical technique for gap balance by tightening the medial collateral ligament (MCL) in total knee arthroplasty (TKA) in patients with fixed valgus deformity.

MATERIALS AND METHODS

A prospective analysis was performed on 15 patients (16 knees) with a fixed valgus deformity that was corrected by tightening the MCL during TKA. A single surgeon performed all the 16 TKAs using nonconstrained posterior substituting implant, with two knees treated with long-stem tibial prosthesis. Clinical scores, knee stability, and radiographic evaluations were recorded preoperatively and postoperatively.

RESULTS

Complete weight-bearing could be carried out under the protection of the brace postoperatively. At the third month after surgery, X-rays showed the brace was not worn. The mean follow-up was 26.6 months (range 12-42 months). The average preoperative mechanical axis was 15.4 ± 2.3° (range 11-25°), and postoperatively it was 0.6 ± 0.1° (range 0-2°). No complication relative to the technique occurred.

CONCLUSION

This new surgical technique has demonstrated excellent early clinical results and can be a good supplement for fixed valgus knee arthroplasty. Level of Evidence: III.

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.

Semi-constrained posterior stabilized total knee arthroplasty reproduces natural deep knee bending kinematics

BACKGROUND

The Flexible Nichidai Knee Posterior Stabilized (FNK-PS) system was designed to provide relatively high varus-valgus stabilities without the stem extensions to patients with severe knee joint disorders. This is a combination of a large tibial post and high femoral cam adapted to a PS system. The aim of our study was to analyze the in vivo two-dimensional/three-dimensional registration kinematics of the FNK PS-total knee arthroplasty (TKA) system during deep knee bending.

METHODS

Nineteen knees from 15 total knee arthroplasty (TKA) patients who were able to squat with enough knee flexion were selected. During deep knee bending under weight bearing (WB) and non-weight bearing (NWB) conditions, we quantified range of motion, axial rotation, femoral anteroposterior translation, and post-cam engagement angle.

RESULTS

The maximum-flexion was significantly different between the two conditions. The mean axial femoral external rotation was 4.8° and 6.2° under WB and NWB conditions, respectively, at 120° flexion. Anteroposterior translation based on bicondylar posterior roll-back patterns was noted with increasing knee flexion. Both the medial and lateral femoral aspects were significantly more posterior during early to mid-flexion. Initial post-cam engagement occurred significantly earlier during flexion under NWB than under WB conditions. Under WB, the timing of the post-cam engagement correlated with the maximum flexion .

CONCLUSIONS

The kinematics of the semi-constrained PS system reproducibly exhibited a mild external rotation with smooth posterior roll-back. This was assisted by the engagement of the large tibial post and high femoral cam during the early phase of flexion.

Primary repair for injury of medial collateral ligament during total-knee arthroplasty

The aim of this study was to determine whether primary repair for intraoperative injury of the medial collateral ligament (MCL) can achieve satisfactory clinical results when compared to the clinical results of patients with no MCL injury. Simultaneously, we sought to determine the differences between 2 methods of primary repair (anchor suture and staple) in terms of their clinical outcomes.In our institute, 3897 total-knee arthroplasties (TKAs) were performed between 2003 and 2014. Sixty-five patients who suffered an MCL injury during the TKA procedure and in whom the injury was repaired with a suture anchor or staple (suture anchor: 36 vs staple: 29) were studied. A matched group of 65 patients without an MCL injury was selected to serve as the control group. Subjective feelings of instability and functional outcomes were assessed using the knee society (KS) score and the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC). Objective stability was evaluated by the measurement of opening angles in extension and at 30° of knee flexion on valgus stress radiographs. The clinical outcomes and stability results were compared between the suture anchor and staple methods.The KS and WOMAC scores in patients who received primary repair of MCL injury during TKA improved from 50.6 ± 13.1 to 87.3 ± 7.3 (P < .001) and 65.9 ± 14.4 to 17.7 ± 6.6 (P < .001), respectively. However, there were no statistically significant differences in the KS (P = .84) and WOMAC (P = .71) scores when comparing the group that received primary repair to the control group. Radiographic stability also showed no differences between the repair and control groups in extension and at 30° of flexion (P = .48 and P = .11, respectively). In the subgroups, there were no significant differences between the suture anchor and staple repair methods in terms of stability and clinical outcomes.Primary repair of an MCL injury during TKA may have clinical outcomes comparable to that in the no MCL injury group. Both staple and suture anchor repair methods could provide excellent clinical and stability outcomes in these types of cases, although a further cohort study is required to validate our results.

Mid-term outcomes following primary semi-constrained total knee arthroplasty in patients less than 60 years old, a retrospective review

INTRODUCTION

Total knee arthroplasty (TKA) is a successful operation for osteoarthrosis. Typically, the knee can be balanced using posterior stabilized or cruciate retaining implants. However, in patients with severe deformity or ligamentous laxity, this cannot be obtained, and more constrained devices are needed. Semi-constrained implants, such as the Total Condylar III (TCIII) provide increased coronal stability. Outcomes in young (<60 years old) patients, following a primary semi-constrained TKA are not well reported in the literature. The purpose of this study was to evaluate patient reported outcomes, functional recovery, and implant survival in this population.

METHODS

We performed a retrospective review of 21 patients, under the age of 60 years, that underwent primary semi-constrained TKA. Patient demographics, postoperative outcomes, patient satisfaction scores, and implant loosening were reported.

RESULTS

At an average follow-up of 66 months, Knee Society Scores (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were 94.7 and 15.7, respectively. No difference in patient reported outcomes between 1 year and final follow-up were observed. Patient demographics such as age, BMI, and gender had no effect on functional outcomes. No cases of aseptic loosening were observed. Implant survivorship, patient satisfaction, and excellent or good results were reported in 100%, 85.7%, and 92%, respectively.

CONCLUSION

In young patients, in which the knee cannot be effectively balanced with standard releases, the use of a semi-constrained TKA as a primary implant lead to positive patient reported outcomes and no evidence of loosening at mid-term follow-up.

Rotational Shortening of Collateral Ligament in TKR With Severe Deformity

Instability of the knee joint after total knee replacement (TKR) is one of the most important reasons for revision TKR. Inadequate release or tightening of the collateral ligaments in the knee joint may cause instability and early failure. This study presents a case series study of a new technique for ligament balancing wherein the collateral ligament is detached from its origin and rotated (twisted) around its longitudinal axis to tighten the ligament before the origin is reattached to its original position. The surgical technique for collateral ligament tightening during TKR was performed on 6 patients with a deformed knee caused by osteoarthritis and rheumatoid arthritis. The range of motion, knee society score, and laxity of the patients' knee joint, after 7 months to 13 years of follow-up, were evaluated. The technique was successful, achieving good range of motion and satisfactory stability of the joint. Further evaluation in a larger number of cases and a comparative analysis with different techniques would further support the usefulness of this rotational ligamentoplasty technique.

The Effectiveness of Medial Femoral Epicondyle Up-Sliding Osteotomy to Correct Severe Valgus Deformity in Primary Total Knee Arthroplasty

BACKGROUND

While many surgical techniques can achieve neutral limb alignment and soft tissue balance in severe valgus deformity during total knee arthroplasty (TKA), few published reports concern medial femoral epicondyle up-sliding osteotomy.

METHODS

A prospective investigation was conducted of patients with severe valgus deformities who underwent medial femoral epicondyle up-sliding osteotomy. Clinical measurements, radiological evaluation, and complication data were recorded.

RESULTS

Using posterior-stabilized prostheses, 26 patients underwent 28 TKAs performed by the same surgeon using medial femoral epicondyle up-sliding osteotomy to balance the soft tissue. On average, the follow-up was 54 ± 18 months, and the patient age was 63 ± 11 years. All knees were type II according to Krackow's classification. Varus-valgus knee motion was prohibited with the protection of long-leg knee brace for 3 months. At the last follow-up, the Knee Society function score, Hospital for Special Surgery knee-rating scale, and range of motion were 94 ± 6, 91 ± 4, and 116° ± 8°, respectively. All knees were stable laterally, whereas 2 knees had mild medial laxity and the others were stable. The hip-knee-ankle angle, femorotibial angle, condylar-hip angle, plateau-ankle angle, and valgus angle were 179.9° ± 3.4°, 172.9° ± 3.6°, 89.8° ± 2.5°, 90.2° ± 1.1°, and 7.3° ± 3.5°, respectively.

CONCLUSION

Medial femoral epicondyle up-sliding osteotomy during TKA in patients with severe valgus deformities facilitates the restoration of lower limb alignment, soft tissue balance, and knee stability.

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.

Primary total knee arthroplasty using constrained condylar knee design for severe deformity and stiffness of knee secondary to post-traumatic arthritis

Background

Key to a successful outcome of total knee arthroplasty (TKA) is to attain optimum alignment, adequate balance, and deformity correction. In primary TKA, this can be achieved efficiently by posterior stabilized (PS) design with or without the sub-periosteal release. However, certain circumstances such as post-traumatic arthritis are often associated with severe deformities with a significant bone defect, stiffness, and instability. Such deformities are extremely difficult to balance with soft tissue release only and require additionally constrained prostheses even in primary TKA. In such situation, constrained condylar knee (CCK) design is the ultimate choice. This study primarily aimed to report on clinical outcome, regain of function, and complication of patients who underwent primary CCK-TKA for severe deformity of the knee secondary to post-traumatic arthritis. The secondary aim was to find out the mid-term prostheses survival.

Methods

Between February 2007 and November 2013, 38 consecutive patients with post-traumatic arthritis of the knee received cemented primary CCK-TKA. Thirty-four patients (21 men and 13 women) who had a minimum of 3 years follow-up were included in this retrospective study. We used Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, and roentgenographic evaluation form to assess the patients. Prostheses survival was assessed using Kaplan-Meier’s survival analysis.

Results

Patients were followed up for an average duration of 6.47 years. KSS knee score improved from 44 points (23–68) pre-operatively to 91 points (76–100) post-operatively [P < 0.001]. The average KSS functional score improved from 49 points (20–75) pre-operatively to 91 points (65–100) post-operatively [P < 0.001]. The average HSS score improved from 51 points (27–83) pre-operatively to 91 points (75–100) post-operatively [P < 0.001]. Similarly, the average ROM improved from 68.09° ± 35.99° (0°–120°) to 113.68° ± 8.90° (100°–130°) post-operatively [P < 0.001]. The average hip-knee-ankle (HKA) angle was 176.88° ± 14.48° (135°–199°) pre-operatively and 180.24° ± 1.77° (175°–184°) post-operatively. Radiolucencies were evident in 13 knees, mostly on the tibial side. Prostheses survival was 94.7% at a mean follow-up of 6.47 years.

Conclusion

Despite severe deformity, instability, and stiffness at a relatively young age, mid-term follow-up of primary CCK-TKA in post-traumatic arthritis provides satisfactory clinical and functional outcomes with 94.7% prostheses survival. However, it is not without complication.

Clinical outcomes of medial collateral ligament injury in total knee arthroplasty

Intraoperative injury to the medial collateral ligament (MCL) during total knee arthroplasty (TKA) is a rare but severe complication. The main treatment methods are primary repair and revision with a more constrained implant; however, the clinical outcomes of primary reconstruction without a constrained implant have rarely been reported.A retrospective study was performed to evaluate the prevalence of iatrogenic injury to the MCL during primary TKA, and to report the clinical outcomes of MCL reconstruction without the use of a constrained device.A total of 1749 patients (2054 knees) underwent primary TKA between 2007 and 2013 and were retrospectively evaluated. Seventeen patients (0.83%) experienced an MCL injury intraoperatively, and the remaining 1732 patients (2037 knees) were considered as the controls. We attempted to reconstruct the MCL with an unconstrained prosthesis in all patients. The Knee Society Score (KSS) was used to evaluate knee function after an average 51-month follow-up (range, 36-72 months).No patients were lost during the follow-up period. In the MCL injury group, the mean KSS was 84.7 for function and 87.7 for pain, while the scores were 87.9 and 90.6, respectively, in the control group. No patient treated with MCL reconstruction without increased prosthetic constraint experienced knee instability requiring revision.MCL reconstruction without a constrained implant achieved excellent results for MCL injury during TKA.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Two cases of late medial instability of the knee due to hip disease after total knee arthroplasty

INTRODUCTION

There are few specific reports of late medial instability after total knee arthroplasty (TKA). We described two cases of late medial instability of the knee due to hip disease with osteoarthritis or rheumatoid arthritis after TKA, which required revision TKA.

PRESENTATION OF CASES

An 82-year-old woman experienced right femoral neck fracture due to a fall that required conservative treatment at age 77 years and underwent left TKA at age 80 years. A 68-year-old woman underwent left TKA at age 54 years, right TKA at age 64 years, and left THA at age 67 years. Both cases required revision TKA with constrained knee prostheses due to the severe medial instability. Hip-knee-ankle (HKA) angle, range of motion (ROM), Knee Society score (KSS) and functional score (FS) were evaluated pre- and postoperatively. Their respective HKA angle improved from 134° and 155° preoperatively to 184° and 179° postoperatively. KSS improved from -4 and 53 points to 59 and 100 points, respectively. FS improved from -10 and 58 points to 25 and 90 points, respectively. In the 82-year-old woman, ROM did not improve from -10-90° to -20-90°. On the other hand, in the 68-year-old woman, ROM improved from 0-110° to 0-125°. The late medial instability in the current case report was partly due to a similar mechanism underlying the long leg arthropathy and coxitis knee caused by hip joint degeneration.

CONCLUSIONS

Constrained prostheses were applied for both patients, providing moderately good short-term results.

Varus-valgus constrained implants in total knee arthroplasty: indications and technique

Total knee arthroplasty is a successful operation that significantly improves patient's quality of life. However, studies demonstrated as only 82% to 89% of patients are satisfied with their surgery, being the other disappointed with regard to their expectations. Two to 5.7% of total knee arthroplasties (TKAs) require revision within 5 years. Both complex primary cases and revision TKA often necessitate for a higher degree of constrain than cruciate retaining or postero-stabilized implant design. In the 1970s varus-valgus constrained (VVC) or semi-constrained implants have been developed by Insall and associates from the PS design, which provide varus-valgus stability preserving a fair amount of host bone. VVC TKAs allows for a small amount of movement in the coronal, antero-posterior and axial planes. In this paper, the authors give an overview of the indications, outcomes and technique for varus-valgus constrained implants, both in the setting of primary and revision knee arthroplasty.

Results of a Second-generation Constrained Condylar Prosthesis in Complex Primary and Revision Total Knee Arthroplasty: A Mean 5.5-Year Follow-up

Background:

The application of second-generation constrained condylar knee (CCK) prostheses has not been widely studied. This retrospective study was carried out to evaluate the clinical and radiographic outcomes of a second-generation CCK prosthesis for complex primary or revision total knee arthroplasty (TKA).

Methods:

In total, 51 consecutive TKAs (47 patients) were performed between June 2003 and June 2013 using second-generation modular CCK prostheses. The follow-up was conducted at 3^rd day, 1^st, 6^th, and 12^th months postoperatively and later annually. Anteroposterior (AP), lateral, skyline, and long-standing AP radiographs of the affected knees were taken. The Hospital for Special Surgery (HSS) Knee Score, the Knee Society Knee Score (KSKS), the Knee Society Function Score (KSFS), and range of motion (ROM) were also recorded. Heteroscedastic two-tailed Student's t-tests were used to compare the HSS score and the Knee Society score between primary and revision TKAs. A value of P < 0.05 was considered statistically significant.

Results:

Four knees (two patients) were lost to follow-up, and 47 knees (31 primary TKAs and 16 revision TKAs) had a mean follow-up time of 5.5 years. The mean HSS score improved from 51.1 ± 15.0 preoperatively to 85.3 ± 8.4 points at the final follow-up (P < 0.05). Similar results were observed in terms of the KSKS and KSFS, which improved from 26.0 ± 13.0 to 80.0 ± 12.2 and from 40.0 ± 15.0 to 85.0 ± 9.3 points, respectively (P < 0.05). No significant difference in the HSS, KSKS, KSFS, or ROM was found between primary and revision TKAs (P > 0.05). Two complications were observed in the revision TKA group (one intraoperative distal femur fracture and one recurrence of infection) while one complication (infection) was observed in the primary TKA group. No prosthesis loosening, joint dislocation, patella problems, tibial fracture, or nerve injury were observed. Radiolucent lines were observed in 4% of the knees without progressive osteolysis.

Conclusions:

Second-generation modular CCK prostheses are a safe and practical treatment for both primary and revision knees that cannot be balanced. However, further studies focusing on different types of constrained prostheses are required to validate these results.

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.

REVISION TOTAL KNEE ARTHROPLASTY USING THE MODERN CONSTRAINED CONDYLAR KNEE PROSTHESIS

Objective:

To determine whether the second-generation constrained condylar prosthesis provided satisfactory results in revision total knee arthroplasty.

Methods:

A series of 41 cases of revision total knee arthroplasty using the second-generation constrained condylar knee prosthesis was reviewed. The series comprised 7 men and 34 women with a mean age of 73.2 years. The original diagnosis was predominantly osteoarthritis. The most common reason for revision surgery was aseptic loosening. The mean interval between the primary and revision surgeries was 66.4 months. The mean follow-up period was 49.4 months.

Results:

The mean Knee Society knee score improved from 43.8 to 82.9 after revision surgery, the mean Knee Society function score improved from 37.1 to 79.2; the range of motion improved from 95.6° to 105.6° and the radiological femorotibial alignment improved from 181.4° (varus 6.4°) to 174.9° (valgus 0.1°), on average (p<0.001 at all items).

Conclusion:

Revision total knee arthroplasty with the use of the second-generation constrained condylar knee prosthesis yielded reproducible clinical success. Level of Evidence IV, Case series.

Does a non-stemmed constrained condylar prosthesis predispose to early failure of primary total knee arthroplasty?

PURPOSE

The use of unlinked constrained condylar components (CCK) has been extended to primary total knee arthroplasty (TKA); however, there is limited literature on its outcomes. The purpose of this retrospective cohort study was to assess clinical outcomes of one particular design of primary, non-stemmed, unlinked constrained TKA and to compare them with a control group of PS-TKA utilizing the same implant design.

METHODS

The clinical and radiographic outcomes of 486-cemented, non-stemmed, primary TKA's performed by two surgeons at one institution using similar surgical algorithm, technique and prosthetic design were retrospectively reviewed. Primary TKA components were used in all knees; the only difference between groups was the type of polyethylene inserts used (CCK vs PS). Pre-operative deformity, knee society scores (KSS), range-of-motion (ROM), radiographic data and revision rates were compared.

RESULTS

Both groups had comparable demographics, pre-operative coronal plane alignment, ROM and KSS. At a mean follow-up of 3.5 years, no difference was found in ROM, KSS, radiographic outcomes and revision rates.

CONCLUSIONS

Cemented, primary, non-stemmed CCK-TKA offered comparable clinico-radiographic results to PS-TKA at short-term follow-up. Use of a semi-constrained insert without additional stems did not predispose to failure due to aseptic loosening with this implant design. Moreover, the rate of revision due to instability was lowered.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Bilateral Diabetic Knee Neuroarthropathy in a Forty-Year-Old Patient

Diabetic osteoarthropathy is a rare cause of neuropathic joint disease of the knee; bilateral involvement is even more exceptional. Diagnosis is often made late due to its unspecific symptoms and appropriate surgical management still needs to be defined, due to lack of evidence because of the disease's low incidence. We report the case of a forty-year-old woman with history of diabetes type I who developed bilateral destructive Charcot knee arthropathy. Bilateral total knee arthroplasty was performed in order to achieve maximal functional outcome. Follow-up was marked by bilateral tibial periprosthetic fractures treated by osteosynthesis with a satisfactory outcome. The diagnosis of Charcot arthropathy should always be in mind when dealing with atraumatic joint destruction in diabetic patients. Arthroplasty should be considered as an alternative to arthrodesis in bilateral involvement in young patients.

Complex Primary Total Knee Arthroplasty: Long-Term Outcomes

BACKGROUND

Total knee arthroplasty in patients with severe preoperative deformity, ligamentous instability, and/or marked bone loss occasionally requires a varus and valgus constrained or rotating-hinge design prosthesis. The purpose of this study was to compare patient populations that underwent primary total knee arthroplasty with constrained or unconstrained total knee arthroplasty implants to determine patient demographic characteristics, long-term survival, and reasons for reoperation and revision for each group.

METHODS

We identified 28,667 primary total knee arthroplasties performed from 1979 to 2013 at our institution. A total of 427 knees had a varus and valgus constrained design and 246 knees underwent rotating-hinge total knee arthroplasties. Patient demographic information and preoperative diagnoses were analyzed by implant type. A multivariate analysis was performed to account for age, sex, and body mass index (BMI). Kaplan-Meier survival rates for each complication leading to reoperation or component revision were determined at 10 and 20 years. Adjusted hazard ratios were determined for the most common causes for reoperation and revision compared with a routine total knee arthroplasty control group.

RESULTS

Patient demographic characteristics were significantly different (p < 0.05) between all groups for age, sex, and BMI. The varus and valgus constrained and rotating-hinge groups had decreased survival free of all-cause reoperation at 10 and 20 years compared with the unconstrained total knee arthroplasty group, with a hazard ratio of 1.74 (95% confidence interval [95% CI], 1.36 to 2.23) for the valgus and varus constrained group and 2.07 (95% CI, 1.58 to 2.70) for the rotating-hinge group. The adjusted hazard ratio for all-cause revision was significantly higher for the varus and valgus constrained group at 1.65 (p = 0.007) but not for the rotating-hinge group at 1.48 (p = 0.054) compared with the unconstrained total knee arthroplasty group. Wear and osteolysis, infection, and fracture were the most common reasons for component revision in both groups.

CONCLUSIONS

We found increased reoperation and revision rates associated with the use of constrained implants at the time of index total knee arthroplasty. The rate of component revision for any reason at 10 years was >2 times higher in the constrained total knee arthroplasty groups compared with the unconstrained total knee arthroplasty group. At 20 years postoperatively, the component revision rate was >3 times higher.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Revision knee surgery techniques

Revision total knee arthroplasty (rTKA) is a challenging, complex procedure. A comprehensive understanding of the anatomy, challenges and pitfalls is essential to achieve a good outcome for the patient.This review discusses the determinants of good outcomes of rTKA. These include, among other factors, the choice of the surgical approach, removal of the components, adequate reconstruction of the joint line and posterior condylar offset and the use of offset stems, as well as choosing the appropriate level of constraint.The modularity of many modern knee revision systems can help to address such issues as anatomical mismatch, gap balancing and malalignment.A well-planned surgical approach must be used in rTKA. A thorough understanding of related knee anatomy is essential.The incidence of joint-line elevation after rTKA is high. Contralateral radiographs, as well as algorithms based on the relationship between bony landmarks and the joint line, can help to reconstruct a physiological joint line during rTKA.Modularity added to systems, such as offset stems, are useful enhancements that may further improve the reconstruction of the anatomy.There are several options for managing the patella, with the best choice depending on the status of the patellar component and residual bone stock. Cite this article: Thienpont E. Revision knee surgery techniques. EFORT Open Rev 2016;1: 233-238. DOI: 10.1302/2058-5241.1.000024.

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

This study aimed to examine the clinical and radiographic outcomes of primary total knee arthroplasy (TKA) with use of NexGen® Legacy® Constrained Condylar Knee (CCK) prosthesis for severe knee deformity. Clinical data of 46 patients (48 knees in total, aged 61 years on average) with severe knee deformity who underwent TKA with NexGen® Legacy® CCK prosthesis between December 2007 and February 2012 were retrospectively analyzed. There were 34 knees with severe valgus with incompetent medial collateral ligament, 11 knees with severe flexion contracture with inability to achieve knee balancing in flexion and extension by posterior soft tissue release, 2 knees with Charcot arthritis with severe varus and bone loss, and 1 with traumatic osteoarthritis with severe varus and ligamentous instability. The mean duration of follow-up was 71 months (range 40-90 months). The New Knee Society scoring (NKSS) system and the Hospital for Special Surgery (HSS) score were used to evaluate the functional and clinical outcomes. Visual Analogue Scale (VAS) was used for pain measurement and Knee Society criteria for evaluation of radiological images. The results showed that, in the total 48 knees, 1 case of loosening due to short-stem tibial component at 3 months post-operatively underwent revision. The 6-year prosthesis survival rate in this cohort was 97.9%. There was no component infection occurring within 6 years. Significant post-operative improvements were found in NKSS and HSS scores. Patient satisfaction was significantly increased. Pain score was decreased significantly. Total functional score was improved from 31.46±11.43 to 86.42±8.87, range of motion (ROM) from 42.42°±23.57° to 95.31°±23.45° and the flexion contracture from 5.31°±7.87° to 0.92°±1.80°. Preoperative radiographic study showed excessive valgus (≥7°) in 37 knees, and varus deformity in 3 knees. Post-operative femorotibial alignment was valgus 3.88°±1.76° in 48 knees. Antero/posterior (A/P) view of X-ray films showed 4 radiolucent lines (RLL) in 48 tibial components. It was concluded that TKA with CCK is effective for the treatment of the severe unstable knee that cannot be balanced by soft tissue.

Radiographic Evaluations of Revision Total Knee Arthroplasty: A Plea for Uniform Assessments

Thorough radiographic evaluation is necessary for perioperative assessments in revision total knee arthroplasty. There has been a large degree of variability in reporting these findings within the peer-reviewed literature. Our purpose was to evaluate studies that radiographically assessed alignment in the coronal and sagittal plane, patella alignment and thickness, presence and characterization of implant interface, and radiolucency. Secondly, we reviewed studies using a standardized reporting system to evaluate radiographic findings (the Knee Society Roentgenographic Evaluation and Scoring System) and the number of times it was referenced. Only 62% of studies evaluated all radiographic parameters, 57% to 91% assessed each metric, and 55% used standardized reporting systems. This emphasizes the need for a uniform evaluation method to ensure consistent radiographic assessment and optimal standard of care.

Long-Term Clinical Outcomes and Survivorship of Revision Total Knee Arthroplasty with Use of a Constrained Condylar Knee Prosthesis

The purpose of this study was to determine long-term clinical and radiographic results. One hundred and ninety-four patients (228 knees) underwent revision TKA with use of a constrained condylar knee prosthesis. The mean duration of follow-up was 14.6 years (range, 11 to 16 years). The mean pre-revision Knee Society knee scores (43.5 points) and function scores (47.0 points), and Western Ontario and McMaster Universities Osteoarthritis index scores (88 points) were improved significantly (P=0.002) to 85.6, 68.5, and 25 points, respectively, at 14.6 years follow-up. Eighteen knees (8%) had re-revision. Four knees were re-revised for infection. Kaplan-Meier survivorship analysis revealed that the 16-year rate of survival of the components was 94.7% as the end point of loosening and 92% as the end point of revision.

Outcome of iatrogenic collateral ligaments injuries during total knee arthroplasty

Soft tissue balance is an essential step in total knee arthroplasty by providing a good knee stability and an even distribution of load over the prosthesis components. During surgery, because of the need of having a good balance in most cases is necessary to do some soft tissue release in the medial compartment. Lateral release is far more rare and is generally needed for patients with valgus knees after high tibial osteotomy. Our purpose is to evaluate the complications that arise during soft tissue release and how to manage this unfortunate events for getting the best functional results for the patients. In this study, we analyzed 434 knee arthroplasties that were operated in our clinic in the past 8 years by the same knee team (2005-2012). Average age was 64.8 years. Eight of this patients had medial collateral ligament injuries during surgery, and two had lateral collateral ligament rupture. Average age of patients who suffered from medial collateral ligaments injuries was 62.8 years and for lateral collateral ligaments was 72.5 years. Body mass index was 34 for both groups. We used for evaluation the knee society pain and functional scores, and X-rays obtained after the surgery with a calibrated Siemens machine. Seven patients with MCL repair were satisfied with after surgery (Knee Society score was 87.7, and functional score was 80). One complained of knee instability associated with pain and needed revision. In LCL group, all patients had excellent results (Knee Society score was 91.5, and functional score was 85). We found that repair to collateral ligaments injuries must be obtained during surgery, especially complete ruptures of the MCL. There are several approaches to collateral ligaments ruptures during total knee arthroplasty that will be discussed during the article.

Primary Repair of Iatrogenic Medial Collateral Ligament Injury During TKA: A Modified Technique

Intraoperative injury to the medial collateral ligament (MCL) is a rare but important complication of total knee arthroplasty (TKA). While described treatment methods are mainly primary repair and revision with a more constrained implant, a few studies have investigated the outcomes of primary repair without constrained implants. A retrospective study was performed to evaluate the prevalence of iatrogenic injury to the MCL during primary TKA and determine the clinical outcomes of MCL repair augmented with synthetic material without the use of a constrained device. The incidence of intraoperative tear of the MCL was 0.43% (15/3432). No patient demonstrated instability during the follow-up period. Primary repair of iatrogenic MCL injury without the use of constrained implants appears to be a potential alternative that warrants further investigation.

Ligament reconstruction/advancement for management of instability due to ligament insufficiency during total knee arthroplasty: a viable alternative to constrained implant

BACKGROUND

We aimed to assess the results of ligament reconstruction/advancement for the management of ligament insufficiency during total knee arthroplasty.

METHOD

We retrospectively reviewed the results of ligament reconstruction/advancement for management of instability due to ligament insufficiency during total knee arthroplasty (TKA). Between January 2001 and January 2008 collateral ligament reconstruction/advancement was done in 15 patients. Wherever ligament advancement was not possible (mid-substance tear) ligament reconstruction was done using the hamstring tendon. Knee society scores were calculated and Kaplan-Meier survival analysis was done.

RESULTS

Average follow-up was 6.2 years. No patient developed instability until the last follow-up, except one patient who required revision due to instability at six years after primary surgery.

CONCLUSION

We concluded from this study that ligament reconstruction/advancement during TKA is a viable option to address instability due to ligament insufficiency.

Survival of primary condylar-constrained total knee arthroplasty at a minimum of 7 years

The purpose of the present study is to retrospectively analyze clinical and radiographic outcomes in primary constrained condylar knee arthroplasty at a minimum follow-up of 7 years. Given the concern for early aseptic loosening in constrained implants, we focused on this outcome. Our cohort consists of 127 constrained condylar knees. The mean age of patients in the study was 68.3 years, with a mean follow-up of 110.7 months. The diagnosis was primary osteoarthritis in 92%. There were four periprosthetic distal femur fractures, with a rate of revision of 0.8%. No implants were revised for aseptic loosening. Kaplan-Meier survivorship analysis with removal of any component as the end point revealed that the 10-year rate of survival of the primary CCK was 97.6% (95% CI, 94%-100%).

Range of motion and function are not affected by increased post constraint in patients undergoing posterior stabilized total knee arthroplasty

BACKGROUND

Constrained primary total knee arthroplasty (TKA) can provide stability in the face of incompetent collateral structures or irreconcilable flexion-extension imbalances. However, little is known about its effect on overall knee range of motion (ROM). This study determines whether TKA with increased constraint affects postoperative ROM.

METHODS

Patients undergoing primary TKA using either posterior stabilized (PS) or constrained condylar knee (CCK) inserts were match-paired based on body mass index, preoperative ROM, and direction and severity of the coronal deformity, yielding 68 pairs. ROM and Knee Society Score (KSS) were obtained preoperatively and at 6 weeks, 4 months, and 1 year.

RESULTS

When the 68 matched pairs were considered, all outcome variables related to ROM between the PS and CCK groups at each of the postoperative intervals were similar. Additionally, both the individual items and combined scores of the KSS were similar between groups at all time points.

CONCLUSIONS

We demonstrate that the use of increased constraint does not affect ROM, relief of pain, or function after TKA.

LEVEL OF EVIDENCE

Level III (retrospective case-controlled study, based on prospectively collected data).

Assessing patient-oriented results after revision total knee arthroplasty

BACKGROUND

Revision total knee arthroplasties (TKA) have been performed with increasing frequency over the last 25 years.

METHODS

In this study, we retrospectively analyzed 78 patients who underwent 78 revision TKAs during the years 2003–2007 with an average follow-up of 81 months (range 60–108 months). All patients were treated with a standard rotating hinge prosthesis (TC3, DePuy, Warsaw, IN, USA) due to significant instability. We evaluated the postoperative results using the Knee Society clinical rating system and the WOMAC rating system.

RESULTS

Clinical results revealed significant improvements in both scores. Complications occurred in almost one-third of the cases, with a reoperation rate of 26 %.

CONCLUSION

Our mid-term findings show that revision TKAs lead to an improvement in patient-perceived outcomes of physical variables. While revision TKA is a useful option for patients, procedure-associated complications should not be neglected. During the course of the procedure, it is important to collect patient-oriented data and focus on responsive and valid scores.

Conversion of fused knee following distal femur tumor surgery to total knee arthroplasty

Conversion of knee arthrodesis to total knee arthroplasty is a difficult procedure accompanied by many complications due to soft tissue and extensor mechanism contracture and bone defects. We report two cases of distal femur osteosarcoma that had been undergone wide resection arthrodesis initially. Arthrodesis was converted to total knee arthroplasty with hinged prosthesis after many years. We describe patients' history and outline their surgical therapy and prognosis. To the best of the authors' knowledge, few cases have been previously reported in the literature.

One stage conversion of an infected fused knee to total knee replacement - a surgical challenge

Background and Purpose:

Two-stage revision arthroplasty is a common technique for the treatment of infected total knee replacement. Few reports have addressed the conversion of a fused knee into a total knee replacement. However, there is no case reported of converting an infected fused knee into a hinge knee using a one-stage procedure.

Methods:

We report on a 51-year old male patient with an infected fused knee after multiple surgeries.

Results and Interpretation:

A one-stage conversion of septic fused knee into total knee arthroplasty by a rotational hinge prosthesis was performed. The case highlights that with profound preoperative assessment, meticulous surgical technique, combined antibiotic treatment and the right implant, one-stage revision in a surgical challenge may have a role as a treatment option with good functional outcome.

Revision total knee arthroplasty with varus-valgus constrained prosthesis versus posterior stabilized prosthesis

PURPOSE

The aims of this retrospective study were to provide the basis for the choice of prosthesis in revision total knee arthroplasty (TKA) and to evaluate the outcome with varus-valgus constrained prosthesis compared with posterior stabilized (PS) prosthesis.

METHODS

One hundred and five patients (121 knees) received revision TKA; of which thirty-seven patients (42 knees) received PS prosthesis and sixty-eight patients (79 knees) received varus-valgus constrained prosthesis. The mean follow-up duration was 64.8 ± 31.5 months and 63.2 ± 28.1 months in the PS and varus-valgus constrained groups, respectively. The criterion of prosthesis choice was a subjective laxity assessed by the surgeon intraoperatively. A multivariate analysis was performed to evaluate the preoperative factors in the choice of the prosthesis.

RESULTS

The grade of femoral bone defect was the only factor that affected the choice of prosthesis. Clinical results improved significantly in both groups after surgery. There were no significant differences in clinical results between the two groups. Complication rates were 9.5 % in the PS group and 10.1 % in the varus-valgus constrained group, and the Kaplan-Meier survivorship analysis revealed 8-year component survival rates of 83.1 and 93.0 % in the PS and varus-valgus constrained groups, respectively.

CONCLUSIONS

Femoral bone defect is an important factor to be considered in the choice of prosthesis for revision TKA. The varus-valgus constrained prosthesis showed an outcome similar to that of the PS prosthesis. For clinical relevance, varus-valgus constrained prosthesis is recommended in revision TKA when the PS prosthesis seems unsuitable for the management of instability.

LEVEL OF EVIDENCE

III.

Poorer survival after a primary implant during revision total knee arthroplasty

PURPOSE

Revision total knee arthroplasty (rTKA) is a complex procedure. Depending on the degree of ligament and bone damage, either primary or revision implants are used. The purpose of this study was to compare survival rates of primary implants with revision implants when used during rTKA.

METHODS

A retrospective comparative study was conducted between 1998 and 2009 during which 69 rTKAs were performed on 65 patients. Most common indications for revision were infection (30%), aseptic loosening (25%) and wear/osteolysis (25%). During rTKA, a primary implant was used in nine knees and a revision implant in 60.

RESULTS

Survival of primary implants was 100% at one year, 73% [95% confidence interval (CI) 41-100] at two years and 44% (95% CI 7-81) at five years. Survival of revision implants was 95% (95% CI 89-100) at one year, 92% (95% CI 84-99) at two years and 92% (95% CI 84-99) at five years. Primary implants had a significantly worse survival rate than revision implants when implanted during rTKA [P = 0.039 (hazard ratio = 4.56, 95% CI 1.08-19.27)].

CONCLUSIONS

Based on these results, it has to be considered whether primary implants are even an option during rTKA.

Mid- to long-term results of revision total knee replacement using press-fit intramedullary stems with cemented femoral and tibial components

This was a retrospective analysis of the medium- to long-term results of 46 TC3 Sigma revision total knee replacements using long uncemented stems in press-fit mode.

Clinical and radiological analysis took place pre-operatively, at two years post-operatively, and at a mean follow-up of 8.5 years (4 to 12). The mean pre-operative International Knee Society (IKS) clinical score was 42 points (0 to 74), improving to 83.7 (52 to 100) by the final follow-up. The mean IKS score for function improved from 34.3 points (0 to 80) to 64.2 (15 to 100) at the final follow-up. At the final follow-up 30 knees (65.2%) had an excellent result, seven (15.2%) a good result, one (2.2%) a medium and eight (17.4%) a poor result. There were two failures, one with anteroposterior instability and one with aseptic loosening.

The TC3 revision knee system, when used with press-fit for long intramedullary stems and cemented femoral and tibial components, in both septic and aseptic revisions, results in a satisfactory clinical and radiological outcome, and has a good medium- to long-term survival rate.

Follow-up of a modular rotating hinge knee system in salvage revision total knee arthroplasty

We evaluated the clinical and radiographic outcomes of salvage knee revisions using a modern-generation, modular, rotating hinge total knee prosthesis in 24 cases with a minimum follow-up of 36 months (mean, 56 months). Indications for revision included aseptic loosening, combined with bone loss and gross collateral ligament instability in all cases. Patients were evaluated clinically and radiographically (Knee Society scores). Knee Society scores improved from 25 preoperatively to 91 postoperatively, and function scores improved from 35 to 85. No loosening of implants was observed. Nonprogressive radiolucent lines were identified around 2 tibial components. One patient required a revision due to patellofemoral subluxation.

Repair of medial collateral ligament injury during total knee arthoplasty

Intraoperative midsubstance lacerations of the medial collateral ligament (MCL) must be addressed during surgery, and failure to obtain coronal plane stability could affect patient outcomes and satisfaction. This article reports our results of a series of patients who sustained an intraoperative MCL injury during a primary total knee arthroplasty and were treated by direct primary repair and no change in implant constraint or postoperative protocol. Over a 5-year period, 9 patients sustained this complication. We reviewed their subjective satisfaction and stability, as well as objective measures such as functional scores, physical examinations, and radiographs. Average patient age was 58 years, and mean patient body mass index was 43.3. All patients were satisfied with the procedure and demonstrated no instability on physical examination. Average Knee Society pain score was 91.5 and functional score was 73.3. No radiographic changes or signs of loosening were noted. This novel approach for intraoperative midsubstance lacerations of the MCL does not involve altering implants or postoperative protocols and has encouraging results.

Management of intraoperative medial collateral ligament injury during TKA

BACKGROUND

Intraoperative injuries to the medial collateral ligament are often unrecognized and failure to appropriately manage ligament loss may result in knee instability and loosening.

QUESTIONS/PURPOSES

We compared the functional scores in patients with iatrogenic injury to the medial collateral ligament (MCL) treated with additional constraint to those without.

METHODS

We retrospectively reviewed the records of all 1478 patients (1650 knees) who underwent primary TKA between 1998 and 2004. Thirty-seven patients (2.2%) had recognized intraoperative injury to the MCL; the remaining 1441 patients (1613 knees) served as controls. We attempted to repair the ligament in 14 patients; increased prosthetic constraint over that planned was used in 30 of the 37 patients. We determined Knee Society scores (KSS) in all patients. Three patients were lost to followup. The minimum followup was 36 months (average, 54 months; range, 36-120 months).

RESULTS

The mean KSS for all MCL injury knees for pain and function averaged 81 and 74 points, respectively, compared with 91 and 87 for the control group. However, in the 30 knees in which the MCL insufficiency was treated with increased constraint, the mean scores for pain and function increased to 88 and 83 points, respectively. Four of the seven patients treated without increased prosthetic constraint were revised for instability; no revisions for instability were performed in the 37 patients treated with additional constraint.

CONCLUSIONS

Recognition of MCL injury during TKA is crucial, since using nonstabilizing inserts was associated with residual instability requiring revision.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Hinged total knee arthroplasty in the presence of ligamentous deficiency

BACKGROUND

Rotating-hinge total knee prostheses may be used for the treatment of global instability about the knee. The designs of previous generations were associated with suboptimal outcomes.

QUESTIONS/PURPOSES

We evaluated the clinical and radiographic outcomes of salvage knee reconstructions using modern-generation, modular, kinematic rotating-hinge total knee prostheses.

METHODS

We retrospectively reviewed 26 rotating-hinge arthroplasty devices to examine whether acceptable results were obtainable using a single arthroplasty design. The average age of the patients was 77 years (SD, 9 years); the minimum followup was 24 months (mean, 46 months; range, 24-107 months). The indication was revision surgery in 21 patients and complex primary surgery in five. Patients were evaluated clinically (Knee Society score) and radiographically (positions of components, signs of loosening, bone loss).

RESULTS

Knee Society pain scores improved from 40 preoperatively to 77 postoperatively, and function scores improved from 36 to 51. ROM improved from -15 masculine to -10 masculine. None of the patients' knee pain or function worsened. No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in three knees. Three patients required reoperations: one showed a supracondylar periprosthetic fracture treated by open reduction and internal fixation, whereas the other two had periprosthetic infections.

CONCLUSIONS

Reconstruction with rotating-hinge total knee prostheses can provide substantial improvement in function and a reduction in pain in extreme circumstances, such as gross instability. We believe this salvage procedure should be reserved for severe ligamentous deficiencies in elderly and sedentary patients or whenever revision surgery techniques fail.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Excursion of oscillating saw blades in total knee arthroplasty

Intraoperative disruption of the medial collateral ligament during total knee arthroplasty is an uncommon complication that can be avoided by retractor placement as well as by careful cutting of the femur and tibia. This study evaluated the excursion of a small and large oscillating saw blade and compared the data against the widths of both the medial and lateral femoral condyle cuts. We discovered that the large saw blade had a statistically significantly larger excursion than the medial and lateral condyle width in women, as well as the lateral condyle width in men. The small saw blade excursion did not exceed any condyle width. We conclude that the smaller saw blade should be considered when making these cuts because the excursion of the large saw blade may exceed the width of cut needed and endanger important structures such as collateral ligaments.