To compare posterior cruciate ligament substituting (PCS) total knee arthroplasty (TKA) and posterior cruciate ligament retaining (PCR) total knee arthroplasty (TKA) to determine if greater overall flexion is obtained with the PCS TKA versus the PCR TKA at two year postoperative follow up. Secondarily, to determine whether there is a difference in the recovery of range of motion over time between the two groups from initial presentation, to discharge, and to follow up visits at three months, one year, and two years. Prospective, randomised double-blind clinical trial consisting of one hundred male and female patients scheduled for primary TKA. Sample size allows detection of a difference of six degrees of knee range of motion using two-tailed tests, =0.05, and 0.20 (80% power). SCORPIO PCL substituting total knee system and the SCORPIO PCL retaining total knee system were implanted for evaluation in this study. Patients were assessed at initial presentation, at postoperative discharge from hospital, and at follow up visits at three months, one year and two years for flexion knee range of motion. Additional data were collected utilizing the WOMAC Osteoarthritis Index, the Knee Society Clinical Rating Scale, the SF-36, and the Knee Society Radiographic Evaluation as well as data on length of stay and surgical time. Subjects were similar in demographic characteristics and all measurements at the baseline initial assessment. No differences were seen in knee flexion at two year follow up as measured using an independent t-test (p> 0.05). Recovery of knee range of motion over time was not different as measured using a two way repeated measures ANOVA (p=0.88 for group effect). Postoperative flexion and recovery of kneww range of motion was not altered following TKA by using PCS or PCR prostheses

Purpose: At a time when total knee arthroplasty (TKA) with an ultra-congruent tibial plateau or a mobile plateau are advocated by many, the question is whether TKA with a fixed plateau preserving the posterior cruciate ligament (PCL) should be abandoned. We analysed the results of 500 Wallaby I TKA with preservation of the PCL and presenting asymmetrical and divergent femoral condyles with a fixed, also assymetrical tibial plateau, at mean follow-up of seven years (1–10). Material and methods: This prospective multicentric study was performed by junior and senior surgeons. Mean patient age was 70.11 years and 91.4% of the patients had primary or secondary degenerative disease. Prior surgery had been performed in 130 knees, mainly for osteotomy (n=40, mostly tibial) and revision of uni-compartmental or total prostheses (n=18). The mean preoperative IKS knee score was 26.11 points, the function score was 29.54. Preoperative alignment was correct for 11.26% of the knees, 27.16% presented > 4° valgus and 61.56% > 3° varus. Nearly all tibial and patellar pieces were cemented. 5.8% of the femoral pieces were not cemented. A prosthesis was implanted on the patella in all knees except four. There were two early infections, one popliteal sciatic paralysis and twelve wound healing problems. General mobilisation under general anaesthesia was performed in 53 knees (10.6%). Results: Twenty-two patients were not retained for analysis, fifteen lost to follow-up and seven deceased at one year. Among the 478 knees followed for one to ten years, there were six late infections (1.25%), one aseptic bipolar loosening (0.2%), 25 patellar fractures (5.23%) including three which required revision (two cerclage, one prosthesis removal), three periprosthetic femur fractures without effect on the clinical or radiographic outcome, one traumatic tear of the medial collateral ligament, and two secondary tears of the PCL without clinical consequences. There were no revisions for instability, generally considered the most frequent reason for TKA revision. The mean postoperative IKS score was 90.6 points and the function score was 59.7 points basically due to patient age and comorbidity. The eight-year survival (Kaplan-Meier method) was 98.2% (95%CI: 99.4–96.9) irrespective of the reason for revision and 99.2% (95%CI 100–98.4%) if the revision was performed for a mechanical problem. Radiographically, more than 70% of the knees were aligned (between 3° valgus and 2° varus) and more than 90% were between 5° valgus and 5° varus. Although it was difficult to measure radiographically polyethylene wear, there was only one case of > 2 mm wear with osteolysis found in 50 knees selected randomly among the knees with more than seven years follow-up. Conclusion: This study, like others reported by authors preserving the PCL, show that preservation of the PCL limits the risk of instability, allowing excellent clinical and radiographic outcome without important polyethylene wear, opening perspectives for good long-term results

Aims. The aim of this study was to assess the effect of posterior cruciate ligament (PCL) resection on flexion-extension gaps, mediolateral soft-tissue laxity, fixed flexion deformity (FFD), and limb alignment during posterior-stabilized (PS) total knee arthroplasty (TKA). Patients and Methods. This prospective study included 110 patients with symptomatic osteoarthritis of the knee undergoing primary robot-assisted PS TKA. All operations were performed by a single surgeon using a standard medial parapatellar approach. Optical motion capture technology with fixed femoral and tibial registration pins was used to assess gaps before and after PCL resection in extension and 90° knee flexion. Measurements were made after excision of the anterior cruciate ligament and prior to bone resection. There were 54 men (49.1%) and 56 women (50.9%) with a mean age of 68 years (. sd. 6.2) at the time of surgery. The mean preoperative hip-knee-ankle deformity was 4.1° varus (. sd. 3.4). Results. PCL resection increased the mean flexion gap significantly more than the extension gap in the medial (2.4 mm (. sd. 1.5) vs 1.3 mm (. sd. 1.0); p < 0.001) and lateral (3.3 mm (. sd. 1.6) vs 1.2 mm (. sd. 0.9); p < 0.01) compartments. The mean gap differences after PCL resection created significant mediolateral laxity in flexion (gap difference: 1.1 mm (. sd. 2.5); p < 0.001) but not in extension (gap difference: 0.1 mm (. sd. 2.1); p = 0.51). PCL resection significantly improved the mean FFD (6.3° (. sd. 4.4) preoperatively vs 3.1° (. sd. 1.5) postoperatively; p < 0.001). There was a strong positive correlation between the preoperative FFD and change in FFD following PCL resection (Pearson’s correlation coefficient = 0.81; p < 0.001). PCL resection did not significantly affect limb alignment (mean change in alignment: 0.2° valgus (. sd. 1.2); p = 0.60). Conclusion. PCL resection creates flexion-extension mismatch by increasing the flexion gap more than the extension gap. The increase in the lateral flexion gap is greater than the increase in the medial flexion gap, which creates mediolateral laxity in flexion. Improvements in FFD following PCL resection are dependent on the degree of deformity before PCL resection. Cite this article: Bone Joint J 2019;101-B:1230–1237

Poor availability of allografts in South Africa has led to an increased use of synthetic augmentation to stabilize knee joints in the treatment of knee dislocations. This study aims to evaluate multiligament knee injuries treated with a posterior cruciate ligament internal brace. The study included patients with knee dislocations who were treated with a PCL internal brace. The internal brace involved the insertion of a synthetic suture tape, which was drilled into the femoral and tibial footprint. Chronic injuries were excluded. Patient-reported outcome scores (PROMs), range of motion, stress X-Rays, and MRI scans were reviewed to assess outcomes. Acceptable outcomes were defined as a Lysholm score of 84 or more, with grade II laxity in no more than one ligament and a range of motion from full extension to 90° or more. The study included eight patients, with a median age of 42, of which five were female. None of the patients had knee flexion less than 90° or an extension deficit of more than 20°. PROMs indicated acceptable outcomes (EQ5D, Tegner Lysholm). Stress radiographs showed less than 7mm (Grade I) of posterior translation laxity in all patients. Four patients underwent MRI scans 1–2 years after the initial surgery, which revealed healing of the PCL in all patients. However, increased signal in a continuous ligament suggested only partial healing in two patients. Tunnel widening of 200% and 250% was noted around the tibial and femoral PCL footprints, respectively. All patients demonstrated stable knees and acceptable PROMs. Tunnel widening was observed in all patients who had MRI scans. Factors such as suspensory fixation, anisometric tunnel position, and the absence of PCL tear repair may have contributed to the tunnel widening

We have examined the relationship between the size of the flexion gap and the anterior translation of the tibia in flexion during implantation of a posterior cruciate ligament (PCL)-retaining BalanSys total knee replacement (TKR). In 91 knees, the flexion gap and anterior tibial translation were measured intra-operatively using a custom-made, flexible tensor-spacer device. The results showed that for each increase of 1 mm in the flexion gap in the tensed knee a mean anterior tibial translation of 1.25 mm (SD 0.79, 95% confidence interval 1.13 to 1.37) was produced. When implanting a PCL-retaining TKR the surgeon should be aware that the tibiofemoral contact point is related to the choice of thickness of the polyethylene insert. An additional thickness of polyethylene insert of 2 mm results in an approximate increase in tibial anterior translation of 2.5 mm while the flexed knee is distracted with a force of between 100 N and 200 N

Background:. For the past four decades controversy surrounds the decision to retain or sacrifice the posterior cruciate ligament during a total knee arthroplasty. To our knowledge no study has been done to describe the effect of releasing the PCL on the range of motion of the knee. Study design:. Case series. Methods:. Computer navigation data (Brainlab) was obtained intra-operatively from thirty patients at total knee arthroplasty. Coronal alignment, maximal passive knee extension and maximal passive flexion was captured before and after release of the PCL. Results:. Releasing the posterior cruciate ligament led to an increase in maximal extension in all patients (av 3,6°) and a decrease in coronal deformity in 63%. The surprising finding was an increase in maximal knee flexion (av 5°, range 0 to 10°.) The increase in maximal flexion was statistically significant. Conclusion:. Sacrificing the posterior cruciate ligament alters the kinematics of the knee and the resultant increase in knee flexion might explain why cruciate sacrificing total knee arthroplasty has superior flexion compared to cruciate retaining designs

The significance of the posterior cruciate ligament in the stability of the knee was investigated in dogs and it was compared with that of the anterior cruciate ligament by studying the changes produced in the knee after transection of either ligament. Osteophyte formation and changes in articular cartilage were less prominent after division of the posterior cruciate ligament. A complete longitudinal tear of the medial meniscus was found in eight out of the 10 dogs who had undergone section of the anterior cruciate but in none of the 10 with section of the posterior cruciate. It appears that, in dogs at least, the posterior cruciate ligament is less important than the anterior in the stability of the knee

Aims. Total knee arthroplasty (TKA) with a highly congruent condylar-stabilized (CS) articulation may be advantageous due to increased stability versus cruciate-retaining (CR) designs, while mitigating the limitations of a posterior-stabilized construct. The aim was to assess ten-year implant survival and functional outcomes of a cemented single-radius TKA with a CS insert, performed without posterior cruciate ligament sacrifice. Methods. This retrospective cohort study included consecutive patients undergoing TKA at a specialist centre in the UK between November 2010 and December 2012. Data were collected using a bespoke electronic database and cross-referenced with national arthroplasty audit data, with variables including: preoperative characteristics, intraoperative factors, complications, and mortality status. Patient-reported outcome measures (PROMs) were collected by a specialist research team at ten years post-surgery. There were 536 TKAs, of which 308/536 (57.5%) were in female patients. The mean age was 69.0 years (95% CI 45.0 to 88.0), the mean BMI was 32.2 kg/m. 2. (95% CI 18.9 to 50.2), and 387/536 (72.2%) survived to ten years. There were four revisions (0.7%): two deep infections (requiring debridement and implant retention), one aseptic loosening, and one haemosiderosis. Results. Kaplan-Meier analysis demonstrated no difference in implant survival according to sex, age, or obesity status. Ten-year PROMs were available for 196/387 (50.6%) surviving patients and were excellent: mean Oxford Knee Score 34.4 (95% CI 32.7 to 36.1); mean Forgotten Joint Score (FJS) 51.2 (95% CI 16.1 to 86.3); mean EuroQol five-dimension five-level questionnaire score 69.9 (95% CI 46.8 to 93.0); 141/196 (71.9%) achieved the 22-point FJS patient-acceptable symptom state (PASS); and 156/196 (79.6%) were “very satisfied or satisfied”. Conclusion. This is the only large study reporting ten-year implant survival and functional outcomes of TKA using a cemented single-radius design and with a CS tibial bearing construct. The findings of excellent implant survival, safety, and functional outcomes indicate that this combination is a safe and effective option in routine TKA. Further investigation of this single-radius design TKA with CS tibial bearings with well-matched patient study groups will allow further insight into the performance of these implants. Cite this article: Bone Joint J 2024;106-B(8):808–816

We investigated the role of a functional brace worn for four months in the treatment of patients with an acute isolated tear of the posterior cruciate ligament to determine whether reduction of the posterior tibial translation during the healing period would give an improved final position of the tibia. The initial and follow-up stability was tested by Rolimeter arthrometry and radiography. The clinical outcome was evaluated using the Lysholm score, the Tegner score and the International Knee Documentation Committee scoring system at follow-up at one and two years. In all, 21 patients were studied, 21 of whom had completed one-year and 17 a two-year follow-up. The initial mean posterior sag (Rolimeter measurement) of 7.1 mm (5 to 10) was significantly reduced after 12 months to a mean of 2.3 mm (0 to 6, p < 0.001) and to a mean of 3.2 mm (2 to 7, p = 0.001) after 24 months. Radiological measurement gave similar results. The mean pre-injury Lysholm score was normal at 98 (95 to 100). At follow-up, a slight decrease in the mean values was observed to 94.0 (79 to 100, p = 0.001) at one year and 94.0 (88 to 100, p = 0.027, at two years). We concluded that the posterior cruciate ligament has an intrinsic healing capacity and, if the posteriorly translated tibia is reduced to a physiological position, it can heal with less attentuation. The applied treatment produces a good to excellent functional result

We report the results of a prospective randomised trial which assessed the role of the posterior cruciate ligament (PCL) following total knee replacement (Genesis I; Smith and Nephew, Memphis, Tennessee). Over a four-year period, 211 patients underwent total knee replacement by the senior author (TJW). They were randomised at surgery to have the PCL either retained, excised or substituted with a posterior stabilised insert. If it was not possible to retain the ligament due to soft-tissue imbalance, it was released from its tibial insertion until suitable tension was obtained. This created a fourth group, those who were intended preoperatively to have the ligament retained, but in whom it was partially released as a result of findings at the time of surgery. All patients were evaluated using the Knee Society rating system (adapted from Insall). A total of 188 patients (212 knees) was available for follow-up at a mean of 3.5 years after surgery. Preoperatively, there was a varus deformity in 191 knees (90%) and a valgus deformity in 21 (10%). There were no statistical differences in the knee or function scores or the range of movement between the excised, retained and substituted groups. There were, however, significantly worse knee and function scores in the group in whom the PCL was released (p = 0.002)

1. Seventeen cases of knee injury are described in which the predominant lesion was rupture of the posterior cruciate ligament. Seven were treated conservatively and ten by surgical repair. 2. Most cases occurred in motor cyclists. 3. The extent of the rupture should be determined by examination under anaesthesia. 4. Early surgical repair is indicated for complete rupture. 5. An effective method of repair is described

The issue of preservation or sacrifice of the posterior cruciate ligament in total knee arthroplasty remains unresolved. We report the results of 200 consecutive total knee arthroplasties performed at our hospital under the direction of the senior author. Pre-operatively, patients were randomly chosen to receive either a Kinemax (posterior cruciate retaining) or a Press-Fit-Condylar (posterior cruciate sacrificing) prosthesis. We implanted 97 Kinemax and 103 Press-Fit-Condylar prostheses which were prospectively followed-up by clinical and radiographic assessment. Review at mean follow-up of 2.7 years showed a satisfactory clinical result in both groups [Surace, et al., 1994]. We present the results of our further review, with maximum follow-up of over nine years (mean: 5.9 years). Revision of the implant has been performed in five knees (three Kinemax and two Press-Fit-Condylar). The polythene spacer had to be replaced in one patient with a Press-Fit-Condylar implant. Patients were assessed with the Hospital for Special Surgery Knee Score and radiologically assessed with the Knee Society Roentgenographic Evaluation and Scoring System. Pre-operative demographics and disease states of the patients were similar, with an average Hospital for Special Surgery Knee Score of 63. At the latest assessment the average knee score was good (85). Remarkably, the mean knee score for the posterior cruciate sacrifice and the PCL groups remains similar (mean: 85). Radiographic evaluation demonstrated that the prosthetic components of both groups were in comparable alignment. The posterior cruciate ligament retained (Kinemax) patient group showed a mean 5.9 degrees of the valgus angle at the knee. The angle in the posterior cruciate ligament sacrifice (PFC implant) group was 6.2 degrees. Evaluation of the radiolucent depths below the femoral, tibial and any patella component showed a mean total depth of 1.5 mm (pcl retaining) and 1.7 mm (pcl sacrificing). Our study presents a quantitative perspective of the results of total knee replacement with proven implant systems and performed in a general orthopaedic unit by both consultants and surgeons in training. The Kinemax (Howmedica) and Press-Fit-Condylar (DePuy Johnson and Johnson) implant systems have both previously demonstrated good results and continue to be available with little subsequent modification. To our knowledge, there have been no other large prospectively randomised studies of posterior cruciate ligament preservation or sacrifice in total knee replacement

High-flexion knee replacements have been developed to accommodate a large range of motion (ROM > 120°) after total knee arthroplasty (TKA). Femoral rollback or posterior translation of the femoral condyles during knee flexion is essential to maximise ROM and to avoid bone-implant impingement during deep knee flexion. The posterior cruciate ligament (PCL) has been described as the main contributor to femoral rollback. In posterior-stabilised TKA designs the PCL is substituted by a post-cam mechanism. The main objective of this study was to analyse the mechanical interaction between the PCL and a highflexion cruciate-retaining knee replacement during deep knee flexion. For this purpose, the mechanical performance of the high-flexion cruciate-retaining TKA design was evaluated and compared with two control designs including a highflexion posterior-stabilised design. Materials & Methods: Prosthetic knee kinematics and kinetics were computed using a three-dimensional dynamic finite element (FE) model of the knee joint. The FE knee model consisted of a distal femur, a proximal tibia and fibula, a quadriceps and patella tendon, a non-resurfaced patella, TKA components and a posterior cruciate ligament in case cruciate-retaining designs were evaluated. Tibio-femoral and patello-femoral contact were defined in the FE knee model and the polyethylene insert was modelled as a non-linear elastic-plastic material. Three different rotating platform TKA systems were analysed in this study: the high-flexion cruciate-retaining PFC Sigma CR150, the high-flexion posterior-stabilised PFC Sigma RP-F and the conventional cruciate-retaining PFC Sigma RP (Depuy, J& J, UK). Both the polyethylene stress characteristics and the tibio-femoral contact locations were evaluated during a squatting movement (ROM = 50° – 150°). Results: During deep knee flexion (ROM > 120°), the high-flexion cruciate-retaining TKA design showed a lower peak contact stress (74.7 MPa) than the conventional cruciate-retaining design (96.5 MPa). The posterior-stabilized high-flexion TKA design demonstrated the lowest peak contact stress at the condylar contact interface (54.2 MPa), although the post was loaded higher (77.4 MPa). All three TKA designs produced femoral rollback in the normal flexion range (ROM ≤ 120°), whereas the cruciate-retaining designs showed a paradoxical anterior movement of the femoral condyles during high-flexion. Discussion: PCL retention is a challenging surgical aim and affects the prosthetic knee load and kinematics as shown in this study. In addition, for adequate functioning the PCL should not be too tight or too lax after surgery. Hence, we investigated the effect of PCL laxity on the prosthetic performance and the best-balanced PCL was used in our simulations. Although PCL balancing is not an issue for posterior-stabilized TKA, we found the tibial post to be loaded relatively high for this implant type

Introduction: Much debate exists regarding sparing or sacrificing the posterior cruciate ligament (PCL). The posterior cruciate ligament is said to maintain proprioception and stabilization post knee arthroplasty. Substitution of the PCL can require more femoral bone resection, but is thought to improve range of motion. Release of the PCL can restore extension and enhance flexion through greater femoral rollback. Bicruciate implants potentially offer greater flexion and enhanced stability. Each implant design with mechanical instruments requires a different surgical technique making it difficult to directly compare the patient and surgical outcomes. Computer navigation eliminates the differences in implantation between the various implant designs and theoretically allows a more direct comparison of implants based on design characteristics and not surgical technique. The purpose of this paper is to review four different implant designs implanted by a single surgeon with a computer assisted, gap balancing technique to determine if there was any difference in patient outcome. Methods: A total of 504 implants consisting of posterior cruciate sparing (PFC-RP), PCL substituting (PFC-RPC), PCL sacrificing (LCS) and bicruciate (Journey) implants performed by a single surgeon were reviewed. The PFC-RP group (260) was the largest, followed by the LCS (124), the PFC-RPF (80) and the Journey Knee (40). Outcomes reviewed were range of motion, function, pain and radiographic data to include alignment and evidence of radiolucency. Results: Demographic data of groups compared included 175 men and 329 women. Mean ages ranged from 61 to 74 years. Preoperative scores among all groups were similar with the cruciate substituting group slightly lower in function, flexion and with more pain before surgery. Overall function improved across all groups through two years, with better scores in the Journey and LCS implants (77 and 73 points) versus RPF (47) and PFC retaining group at (68) at one year (A perfect score is 100). Flexion values were comparable between all groups at one and two year intervals with Journey the highest mean flexion (116 degrees) at one year and with the PFC-RP offering the highest mean flexion at the two year mark (115 degrees). The RPF group at the one year mark had more pain overall (28) versus the other three groups (Journey 45, LCS 42, Sigma RP 45). No patients in any group were revised for instability. Other surgical complications were equal in each group. Discussion: While the PCL substituting knee patients (PFC-RPF) had lower pain, function and flexion at 12 months compared to all other groups, they started with lower overall knee scores. After accounting for the differences in patients preoperatively, no difference could be found between implant designs when implanted with a similar surgical technique employing a computer assisted gap balancing protocol

The role of posterior cruciate ligament (PCL) in total knee replacement (TKR) has been a matter of debate for long time and remains controversial. In this study, the effect of posterior cruciate ligament (PCL) sacrifice on the tibiofemoral joint gap was analysed in 30 varus osteoarthritic knees undergoing posterior stabilized total knee replacement. Medial soft tissue was released and bone cut was made without preserving the bone segment of tibial PCL insertion. Then the medial and lateral joint gaps in full extension and 90□& lsaquo; flexion were measured before and after PCL sacrifice using a tensioning device (V-STAT tensor(tm), Zimmer). After PCL sacrifice, the flexion gap significantly increased both in medial and lateral side (4.8 □} 0.4 and 4.5 □} 0.4 mm respectively, mean □} SE) compared to those seen in the extension gap (0.9 □} 0.2 and 0.8 □} 0.2 mm, p < 0.001 ANOVA). There was no significant difference between the changes in the medial and lateral gap (p = 0.493). In conclusion, results of this intraoperative measurement showed that PCL sacrifice leads to a selective increase in the size of flexion gap by an average of 4.7 mm whereas it had little impact on the correction of varus deformity. These findings provided insights as for the role and necessity of PCL sacrifice in the correction of varus and flexion deformity. Because the flexion gap surpassed the unchanged extension gap during PCL sacrifice, PCL release could be used as a surgical technique to balance the gaps without additional bone cut

We report a retrospective analysis of the results of combined arthroscopically-assisted posterior cruciate ligament reconstruction and open reconstruction of the posterolateral corner in 19 patients with chronic (three or more months) symptomatic instability and pain in the knee. All the operations were performed between 1996 and 2003 and all the patients were assessed pre- and post-operatively by physical examination and by applying three different ligament rating scores. All also had weight-bearing radiographs, MR scans and an examination under anaesthesia and arthroscopy pre-operatively. The posterior cruciate ligament reconstruction was performed using an arthroscopically-assisted single anterolateral bundle technique and the posterolateral corner structures were reconstructed using an open Larson type of tenodesis. The mean follow up was 66.8 months (24 to 110). Pre-operatively, all the patients had a grade III posterior sag according to Clancy and demonstrated more than 20° of external rotation compared with the opposite normal knee on the Dial test. Post-operatively, seven patients (37%) had no residual posterior sag, 11 (58%) had a grade I posterior sag and one (5%) had a grade II posterior sag. In five patients (26%) there was persistent minimal posterolateral laxity. The Lysholm score improved from a mean of 41.2 (28 to 53) to 76.5 (57 to 100) (p = 0.0001) and the Tegner score from a mean of 2.6 (1 to 4) to 6.4 (4 to 9) (p = 0.0001). We conclude that while a combined reconstruction of chronic posterior cruciate ligament and posterolateral corner instability improves the function of the knee, it does not restore complete stability

The posterior cruciate ligament (PCL) was imaged by MRI throughout flexion in neutral tibial rotation in six cadaver knees, which were also dissected, and in 20 unloaded and 13 loaded living (squatting) knees. The appearance of the ligament was the same in all three groups. In extension the ligament is curved concave-forwards. It is straight, fully out-to-length and approaching vertical from 60° to 120°, and curves convex-forwards over the roof of the intercondylar notch in full flexion. Throughout flexion the length of the ligament does not change, but the separations of its attachments do. We conclude that the PCL is not loaded in the unloaded cadaver knee and therefore, since its appearance in all three groups is the same, that it is also unloaded in the living knee during flexion. The posterior fibres may be an exception in hyperextension, probably being loaded either because of posterior femoral lift-off or because of the forward curvature of the PCL. These conclusions relate only to everyday life: none may be drawn with regard to more strenuous activities such as sport or in trauma

To investigate the effectiveness of avulsion fracture of tibial insertion of posterior cruciate ligament using the safe postero-medial approach through analyzing the clinical and radiographic outcomes. We treated 14 cases of acute PCL tibial avulsion fracture with “safe postero-medial approach”. The PCL and avulsion bony fragment was fixed with 1 cannuated screw and washer. The patients were assessed clinically and radiographically at 3 months, 6 months, and 12 months. Clinical examination for each visit included assessment of the knee range of motion, using goniometer and the posterior drawer test. The patients were evaluated according to the Lysholm and Tegner rating scales. Patients were followed-up for 12 to 16 months. X-ray showed that satisfactory reducdtion and bony healing was achieved in all cases. There was no neurovascular complication. All patients had negative posterior drawer tests. Excellent outcomes were reported by all patients with the Lysholm score system. And there was no signicant difference between the Tegner scores before injury and last follow-up. Surgical treatment of acute tibial avulsion fracture of the PCL with this approach can restore the stability and fuction of the joint safely in most patients without neurovascular complication. Therefore “safe postero-medial approach” may be suitable for the treatment of isolated tibial avulsion fracture of the PCL

We analysed the long-term results with a mean follow-up of 10.2 years, of 66 total knee replacements in 42 patients with rheumatoid arthritis. In all cases the posterior cruciate ligament was retained. There were only three complications (4.5%). Revision surgery was necessary in five knees (7.6%), including one (1.5%) with infection. At the final follow-up, 75.8% of knees were rated excellent clinically. Only 15% had an excellent function score. The survival rate of the implant was 90.7% at 19 years. The clinical, radiological and survivorship analysis shows that the posterior-cruciate-retaining knee arthroplasty performs well in rheumatoid arthritis

We compared function in two groups of high demand patients who had undergone total knee arthroplasty (TKA), one group using a posterior cruciate sacrificing (PCS) prosthesis and the other a posterior cruciate retaining (PCR) prosthesis of similar design. Patients were eligible for the study if surgery had been performed more than two years ago and they were under 65 years of age and had no coexisting morbidity that markedly decreased their physical activities. One surgeon operated on 28 patients in group A (20 TKAs), routinely retaining the posterior cruciate ligament (PCL). A second surgery operated on 19 patients in group B (25 TKAs) and routinely sacrificed the PCL. A mobile bearing prosthesis of similar design was used in each group. Patients were independently selected and assessed using a questionnaire specifically developed to assess higher levels of activity not usually assessed by other knee scores. Patients in the two groups were matched in terms of age, range of motion and follow-up. The gross activity score was 3.36 in group A and 3.12 in group B. The combined walking, running and stair-climbing score was in group A (7.68) than in group B (6.64). Patients in group B had decreased anterior knee pain and perceived their TKA closer to a normal knee (2.00 compared to 2.32). We conclude that retaining the PCL in TKA results in better patient function without obvious complications

We have assessed the clinical and radiological outcome of traumatic knee injuries resulting in open reconstruction of the posterior cruciate ligament using synthetic ligaments at the University of Toronto, Ontario. Pre and post-operative stress radiographs at 30 and 90 degrees were performed, along with IKDC, Lysholm and Tegner scoring. Between 1995 and 2002, 11 patients were operated on. The average time to surgery was 42.3 months (range 1 to 252 months). The average age at time of surgery was 34.1 (26 – 48). The length of follow up ranged from 6 to 87 months. IKDC scoring showed that no patient returned to normal. 5 were nearly normal, 4 abnormal and 2 severely abnormal. The average Lysholm score was 83 (58 – 95). 2 scored excellent, 6 good, 2 fair and 1 poor. The average Tegner score pre-injury was 6.3, prior to surgery 1.8 and post-operatively 3.9 (twice weekly jogging). Stress radiographs showed a decrease in antero-posterior laxity at 30 and 90 degrees although statistical significance was not achieved (p = 0.229 and 0.474 respectively). We conclude that PCL reconstruction restores the normal biomechanics of the knee allowing a more normal function. The synthetic ligament allowed early weight bearing and range of movement mobilisation. The Tegner scores showed a considerable improvement from pre to post-operative values. The stress radiographs showed a decrease in the antero-posterior laxity. Although the IKDC scores did not show any normal knees post-operatively, this was expected due to the severity of the initial injuries. The authors recommend the use of synthetic ligaments to reconstruct the PCL

We assessed arthroscopically 22 young athletes with an isolated acute posterior cruciate ligament (PCL) injury. Four had significant damage to the articular cartilage of the medial femorotibial compartment and were advised not to resume sports. Three underwent PCL reconstruction because of a reparable meniscal tear or instability. The other 15 were treated conservatively and resumed sport. At an average follow-up of 51 months, one had developed arthritic symptoms due to newly-developed severe chondral damage to the medial femoral condyle, but none of the other 14 had developed arthritic symptoms and most remained athletically active. Severe chondral damage should be seen at an early arthroscopy. Knees with an isolated injury to the PCL with concomitant articular damage may be successfully managed by conservative treatment

Computational modeling has been used to simulate the natural and prosthetic kinematic and kinetic function in an attempt to compare designs and/or predict a desired motion path from a design. The levels of soft tissue can range from basic ligaments (MCL, LCL, and ACL & PCL) to more complex models. The goal of this study was to evaluate the sensitivity of the Posterior Cruciate ligament in a virtual model and its effects on the kinematic outcome in a commercially available and validated kinematics package (KneeSim, LifeModeler San Clemente, CA). Methods:. KneeSIM is a musculoskeletal modeling environment that is built on the foundation of the ADAMS (MSC Software, Santa Ana CA), a rigid body dynamics solver to compute knee kinematics and forces during a deep knee bend. All parameters are customizable and can be altered by the user. Generic three dimensional models of cruciate retaining components of the femoral, tibial, and patellar are available with the software and were used to provide a common reference for the study. The following parameters were modified for each simulation to evaluate the sensitivity of the PCL in the model: 1) Model without PCL, 2) PCL with default properties, 3) PCL Shifted at femoral origin, 7 mm anterior, 7 mm inferior; tibial origin maintained; 4) PCL with increased stiffness properties (2x default), 5) position in the femur and tibia remained default position and 6) PCL with default properties and location, joint line shifted 4 mm superior. The standard output of tracking the flexion facet center (FFC) motion of the medial and lateral condyles was utilized (Figure 1). Results:. Figure 2 and 3 displays the output of the six conditions tested above. Comparing the curves for the medial and lateral motion show different patterns with the lateral point having more posterior translation than the medial. After approximately 95° of flexion, all cases exhibit an anterior translation in the model. This motion was consistent for all test cases. The model showed no difference with motion either with or without the PCL and with changing the stiffness. Altering the location of the PCL on the femoral insertion had the greatest effect on motion, while shifting the joint line superior was second. The shift of the ligament insertion and changing of the joint line results in the ligament being more parallel to the tibial surface which provides resistance to anterior motion or posterior translation. Discussion:. Although the model was able to discern differences, the inability to highlight variation in motion with and without the PCL suggests that the default parameters are not representative of an experimental or clinical setup. Although it is apparent that KneeSim can be used for comparative assessments between designs, simulations should be designed so as to provide similar boundary conditions. Publications (Colwell et al 2011) did successfully use KneeSim to provide a comparative assessment of CR components; however, only after the default model was altered to match the outcome of the experimental rig. Further analysis of the complexities in soft tissue modeling is warranted

Purpose. We conducted a prospective study to investigate the role of the LARS ligament system to reconstruct the posterior cruciate ligament and the postero-lateral corner of the knee. We present a prospective single surgeon case series to evaluate early clinical and functional outcomes of postero-lateral corner and posterior cruciate ligament reconstruction in the knee using the LARS (ligament Augmentation and Reconstruction System) artificial ligament. 23 patients with multi-ligament knee injuries or isolated PCL injuries were treated with a mean follow up of 8 months (range: 2-37 months). Outcomes were assessed using the modified International Knee Documentation Committee score, and a modified Tegner- Lysholm score. 2 patients had acute reconstructive surgery within 7 days of injury, 5 patients within 3 months (semi-acute) and 16 were chronic cases that were operated on after three months from the date of injury. The LARS ligament reconstruction achieved a significant improvement between preoperative and postoperative assessment in relation to knee stability, function and patient satisfaction. The sooner the patients were treated the greater the improvements in functional scores were noted. Most patients achieved a full functional range of movement within six months. We had 2 complications, one superficial wound infection and one stiff knee requiring a manipulation. To date we have had no LARS ligament failures. In the short term the LARS functions well, with high clinical patient satisfaction, no signs of progressive laxity, synovitis or failure. We found no significant difference in functional score post reconstruction between the isolated PCL reconstructions and the multi ligament reconstructions. Our results show no early signs of the problems associated with synthetic grafts used in the past. Such grafts appear to be an attractive alternative to the use of autografts and allografts

Purpose: To introduce modified tibial inlay technique for autogenous bone-patellar tendon-bone (BPTB) posterior cruciate ligament (PCL) reconstruction and evaluate the outcomes of PCL reconstruction by this method. Methods: Fifty patients who underwent autogenous BPTB PCL reconstruction using modified tibial inlay technique were evaluated at average 30.9 months (range 12–52). The outcomes were assessed by stress radiographs, maximal manual test with KT-2000 arthrometer, IKDC grading and OAK knee score. Results: Average side to side difference in push view with Telos stress device decreased from 11.7mm to 3.2mm. Difference in maximal manual test with KT-2000 arthrometer also decreased from 11.5mm to 3.1mm. Final IKDC grading was A in six patients, B in thirty four, C in nine and D in one. Average OAK score improved from 64.3 to 86.4. Conclusion: We consider that the modified tibial inlay technique is a method to reduce technical effort and contribute to satisfactory clinical results in autogenous BPTB PCL reconstruction

Aim: To analyse the posterior and external rotational laxities in single bundle PCL (sPCL) and double bundle PCL reconstruction (dPCL) in a PCL and PLC deficient knee.

Methods: Ten fresh frozen were used. A custom made wooden rig with electromagnetic tracking was used to measured knee kinematics. Each knee was tested with posterior and anterior drawer forces of 80N and an external rotation moment of 5Nm when intact, after PCL resection, after dividing the PLC and after performing dPCL and sPCL reconstructions with a bone patellar tendon bone allograft and tibial inlay technique.

Results: The one-tailed paired Student’s t test with Bon-ferroni correction was used. There was a significant difference between the ability of the dPCL and sPCL reconstruction to correct the posterior drawer in extension (p=0.002). There was no difference between the dPCL reconstruction and the intact condition of the knee near extension (p=0.142, Fig 1). There was no significant difference between the intact condition and both sPCL (p=0.26) and dPCL (p=0.20) reconstructions in flexion in restoring posterior laxity. Neither of the reconstructions could restore the rotational laxity (Fig 3).

Conclusion: In a combined PCL and PLC deficient knee the posterior laxity can be controlled by both the sPCL as well as the dPCL reconstructions except near extension where the dPCL reconstruction was better.

Introduction. t is accepted dogma in total knee arthroplasty (TKA) that resecting the posterior cruciate ligament (PCL) increases the flexion space by approximately 4mm, which significantly affects intra-operative decisions and surgical techniques. Unfortunately, this doctrine is based on historical cadaveric studies of limited size. This study purpose was to more accurately determine the effect of PCL resection on the tibiofemoral flexion gap dimension in vivo in a large sample. Methods. Tibiofemoral joint space measurements were made during 127 standardized TKAs by two arthroplasty surgeons. A medial parapatellar approach, computer navigation and provisional tibial and femoral bone cuts were performed in all cases with particular attention to preserving PCL integrity. Cases with an incompetent or damaged PCL were excluded. The tibiofemoral gap dimension was measured with a calibrated tension device at full extension, 45-degrees, and 90-degrees before and after complete PCL resection. Results. 52% of patients were female (66/127), with mean age and BMI of 69.4 years and 34.3 kg/m. 2. , respectively. After PCL resection, the mean joint space dimension increased 0.3mm (range, 0–3mm) at extension, 0.9mm (range, 0–4mm) at 45-degrees, and 1.7mm (range, 0–5mm) at 90-degrees (p<0.001). The 90-degree flexion space opened ≤1mm in 48% of patients and ≥3mm in only 10%. Dividing the flexion gap change by the femoral implant dimension to account and calibrate for patient size, the joint space at 90-degrees increased more in females (0.031 vs. 0.023, p=0.022). Conclusion. The tibiofemoral joint space increases progressively from extension, to mid-flexion through 90-degrees flexion after PCL resection, yet is substantially less than reported in historical studies. However, large variation in the degree of flexion space opening was observed with some patients failing to increase their flexion space whatsoever with PCL resection. This runs counter to conventional TKA understanding and should be considered in modern surgical techniques and education. For figures, tables, or references, please contact authors directly

Objective. The aim of this study was to assess the results of combined arthroscopically assisted posterior cruciate ligament reconstruction and open reconstruction of the posterolateral corner in patients with chronic (3 months or more) symptomatic instability and pain. Patients & methods. A retrospective analysis of all the patients who had a combined reconstruction of the posterior cruciate ligament and the posterolateral corner between 1996 and 2003 was carried out. Nineteen patients who had the combined reconstruction were identified from the database. All the patients were assessed pre- and post-operatively by physical examination and three different ligament rating scores. All the patients also had weight bearing radiographs, MRI scans and an examination under anaesthesia and arthroscopy pre-operatively. The PCL reconstruction was performed using an arthroscopically assisted single anterolateral bundle technique and the posterolateral corner structures were reconstructed using an open Larson type of tenodesis. Results. Pre-operatively all the patients had a grade III posterior sag and demonstrated more than 20 degrees of external rotation as compared to the opposite normal knee on the Dial test. The average follow-up was 66.8 months (range 24 -108). Post-operatively 7 patients had no residual posterior sag, 11 patients had a grade I posterior sag and 1 patient had a grade II posterior sag. Five of the 19 patients demonstrated minimal residual posterolateral laxity. The Lysholm score improved from a mean of 41.2 to 76.5 (P=0.0001) and the Tegner score from a mean of 2.6 to 6.4 (p=0.0001). Conclusions. We conclude that while a combined reconstruction of chronic posterior cruciate ligament and posterolateral corner instability does not restore complete anatomical stability, improvement in symptoms and function demonstrate its value in these difficult injuries

Aim: To compare the function in two groups of high demand patients with a total knee arthroplasty (TKA) – one group using a posterior cruciate sacrificing (PCS) prosthesis and the other a posterior cruciate retaining (PCR) prosthesis of similar design. Method: Patients were eligible for the study if they were greater than two years from surgery, less than 65 years of age and without other co-existing morbidity to significantly decrease their physical activities. Group A underwent surgery by one surgeon who routinely retained the posterior cruciate ligament whereas Group B underwent surgery by one surgeon who routinely sacrificed the PCL. A mobile bearing TKA of similar design was used in each group. All patients were selected and assessed by an independent assessor using a questionnaire developed specifically to assess higher levels of activity not usually assessed by other knee scores. Results: Group A (28 TKA in 20 patients) were matched with Group B (25 TKA in 19 patients) for age, length of follow-up and range of motion. The gross activity score was 3.36 in Group A compared with 3.12 in Group B. The combined walking, running and stair climbing score was significantly better in Group A (7.68 compared to 6.64 in Group B). Group B perceived their TKA was closer to a normal knee (2.00 compared to 2.32) with decreased anterior knee pain. Conclusions: Retaining the PCL in TKA results in better function without significant complications

Introduction: The amount of loading on the cruciate ligaments depends on the tension of the external muscular structures. In vivo studies using EMG have observed a proprioreceptive eccentric co-contraction of the hamstrings during isokinetic knee extension motion. This antagonistic co-contraction increases the quadriceps force necessary to produce the same extension moment on the knee, whereas the loading on the anterior cruciate ligament was measured to be reduced, with the loading on the posterior cruciate ligament to be increased. The objective of this study was thus to investigate the effect of simulated proprioreceptive co-contraction of the hamstrings muscles on quadriceps force, as well as on the relative loading on the cruciate ligament structures during knee extension under dynamic conditions and physiologic loads. Methods: Five fresh frozen knee specimen were tested in isokinetic extension. Bow shaped loading transducers were fixed in the medial fibres of the anterior (ACL) and posterior cruciate ligament (PCL). The test cycle simulated an isokinetic extension cycle from 120 degrees of flexion to full extension, a hydraulic cylinder thereby applied sufficient force to the quadriceps tendon in a closed-loop control cycle to produce a constant extension moment of 31 Nm about the knee. A second hydraulic cylinder simulated a 200 N co-contraction force of the hamstrings tendons. The loading on the ACL and PCL was first measured in the absence of hamstrings force, and subsequently under constant co-contractive flexion force. Results: In the absence of hamstring tension, the maximum quadriceps force was 1190 N ( SD 204 N) at 105 degrees of knee flexion. The loading on the ACL was reduced at larger flexion angles, the loading pattern of the PCL showed an inverse relationship with less loading at full extension. The maximum loading in the ACL was 161 N (SD138 N) and maximum tension in the PCL was 38.2 N (SD 34.9). With hamstring co-contraction, maximum quadriceps force increased 19.9 % ( SD 21.0% p= 0.33), maximum tension in the ACL decreased 71.9% (SD 74.3%, p=0.03), and maximum tension in the PCL increased 73.0% (SD 40.9%, p=0.03). Discussion: This experimental setup enabled direct in vitro measurement of ACL and PCL loading during simulated isokinetic extension motions. The loading on the ACL was dependent on the knee flexion angle. We observed that co-contraction of the hamstrings reduces loading on the anterior cruciate ligament without a significant concomitant increasing the quadriceps muscle force. Our results support the hypothesis that antagonistic co-contraction of the hamstrings during extension of the knee provides an important protective function. In contrast, loading in the posterior cruciate ligament increased during hamstring activation at higher knee flexion angles

Objective: The aim of this study was to assess the results of combined arthroscopically assisted posterior cruciate ligament reconstruction and open reconstruction of the posterolateral corner in patients with chronic (3 months or more) symptomatic instability and pain. Patients & Methods: A retrospective analysis of all the patients who had a combined reconstruction of the posterior cruciate ligament and the posterolateral corner between 1996 and 2003 was carried out. Nineteen patients who had the combined reconstruction were identified from the database. All the patients were assessed pre and post-operatively by physical examination and three different ligament rating scores. All the patients also had weight bearing radiographs, MRI scans and an examination under anaesthesia and arthroscopy pre-operatively. The PCL reconstruction was performed using an arthroscopically assisted single anterolateral bundle technique and the posterolateral corner structures were reconstructed using an open Larson type of tenodesis. Results: Pre-operatively all the patients had a grade III posterior sag and demonstrated more than 20 degrees of external rotation as compared to the opposite normal knee on the Dial test. The average follow up was 66.8 months (range 24–108). Post-operatively 7 patients had no residual posterior sag, 11 patients had a grade I posterior sag and 1 patient had a grade II posterior sag. Five of the 19 patients demonstrated minimal residual posterolateral laxity. The Lysholm score improved from a mean of 41.2 to 76.5 (P=0.0001) and the Tegner score from a mean of 2.6 to 6.4 (p=0.0001). Conclusions: We conclude that while a combined reconstruction of chronic posterior cruciate ligament and pos-terolateral corner instability does not restore complete anatomical stability, improvement in symptoms and function demonstrate its value in these difficult injuries

Objectives. Because posterior cruciate ligament (PCL) resection makes flexion gaps wider in total knee replacement (TKR), preserving or sacrificing a PCL affects the gap equivalence; however, there are no criteria for the PCL resection that consider gap situations of each knee. This study aims to investigate gap characteristics of knees and to consider the criteria for PCL resection. Methods. The extension and flexion gaps were measured, first with the PCL preserved and subsequently with the PCL removed (in cases in which posterior substitute components were selected). The PCL preservation or sacrifice was solely determined by the gap measurement results, without considering other functions of the PCL such as ‘roll back.’. Results. Wide variations were observed in the extension and flexion gaps. The flexion gaps were significantly larger than the extension gaps. Cases with 18 mm or more flexion gap and with larger flexion than extension gap were implanted with cruciate retaining component. A posterior substitute component was implanted with the other cases. Conclusions. In order to make adequate gaps, it is important to decide whether to preserve the PCL based on the intra-operative gap measurements made with the PCL intact. Cite this article: Bone Joint Res 2014;3:95–100

Purpose: The purpose of this work was to evaluate function of 256 total knee arthroplasties (TKA) (Wallaby) with preservation of the posterior cruciate ligament and to compare the femorotibial angle obtained postoperatively. Material and methods: This prospective study included 256 consecutive TKA (cemented Wallaby 1) in 249 patients (mean age 68 years) with osteoarthritis (n=249) or rheumatoid polyarthritis (n=7). Pre- and postoperative clinical findings (HKS score, flexion, extension, laxity, walking distance, use of crutches) and AP full leg views with 20° loaded lateral views pre- and postoperatively (mechanical femoral, mechanical tibial, and femorotibial angles, tibial slope, patellar height, anterior tibial translation) were recorded. Results: The 256 TKA were reviewed at a mean 3-year follow-up. Flexion amplitude was the evaluation criterion. Mean preoperative flexion was 109° (40–130°) with mean persistent flexion of 5° (0°–40°). Mean postoperative flexion was 98° (30–130°) with no persistent flexion. The mean preoperative femorotibial angle was 181.8° (160–201°) and was 180.4° (172–195°) postoperatively. The mean preperative mechanical femoral angle was 88° (82–96°) and 89.8° (80–96°) postoperatively. Mean mechanical tibial angle was 93° (85–104°) and 90.4° (84–86°) postoperatively. Discussion: For certain authors, the only parameter predictive of postoperative flexion after gliding TKA with preservation of the posterior cruciate ligament is preoperative flexion. The statistical analysis of our series showed that correction of the femorotibial malalignement in the frontal plane was not correlated with postoperative knee function and precisely with postoperative flexion. Postoperative flexion was correlated with preoperative flexion. Our results on postoperative flexion of TKA related to preoperative flexion are in agreement with earlier analyses reported in the literature that do not find any absolute correlation with a neutral femorotibial angle in the frontal plane. Conclusion: The quality of the functional outcome after total knee arthroplasty cannot be predicted solely on the correction of the initial deformity

Purpose: We report the results at more than five years of a consecutive series of total knee arthroplasties (TKAs) implanted without cement and with preservation of the posterior cruciate ligament (PCL). Material and methods: This series included 98 patients who underwent 109 primary TKAs between 1994 and 1998. Mean patient age was 67.7 years. The press-fit Interax prosthesis has a macroporous hydroxyapatite coating since 1996. The patella was resurfaced in 92% of the cases with a cemented polyethylene button. Ligament balance and joint space were controlled by progressive release of the ligaments with a tensor derby. Clinical assessment was based on the KSS. Radiological assessment included the femorotibial axis, the position of the implants, and the bone-implant interfaces. Results: Seven (6.4%) of the patients were lost to follow-up. Fifteen (13.4%) died or were demented and two (1.8%) developed late infection and were not included in the primary analysis. Thus, 85 patients (77.9%) were retained for analysis at a mean 5.2 years follow-up. The KSS improved from 33.4 preoperatively to 79.4 at last follow-up. The KSS function score improved from 55.1 to 82.4. Knee flexion was 124.5° preoperatively and 113.1° at last follow-up. Anteroposterior laxity greater than 5 mm was observed in 4.8% at last follow-up. Radiologically, the mechanical femorotibial axis changed from 184.4° to 180.6°. Alpha 95.6°, geta 89.1°, omega 4.77°, gamma 3.8°, sigma 89.4°. Patellar height was 0.84 preoperatively and 0.65 at last follow-up. Lucent lines were observed 3.5 times less frequently with hydroxyapatite coated implants. Patellar loosening and femorotibial loosening were observed in one patient each. Revision procedures were necessary for three prostheses for bipolar loosening, painful stiff knee, and anteroposterior instability. Non-infectious survival rate was 94.1% at 5.2 years. Discussion: These mid-term clinical results are comparable with those reported in the literature for cemented or non-cemented implants with or without preservation of the posterior cruciate ligament. Longer follow-up is however necessary to assess the anteroposterior stability. The radiographic measurements provide a good demonstration of the operative precision and proper ligament balance. Hydroxyapatite coating improves bony fixation of the implants and provides a fixation comparable with cemented implants. Conclusion: This series confirms the mid-term reliability of the non-cemented Interax THA with preservation of the posterior cruciate ligament

Purpose: The posterior cruciate ligament (PCL) has two strands, an anterolateral strand (AL) and a posteromedial strand (PM). Its femoral insertion fans out over 3 cm and cannot be replaced by a unique transplant during surgical reconstruction. The purpose of this study was to define the anatomic centre of the femoral insertion of each stand in order to identify precise and reproducible landmarks for the bone tunnels (one for each strand) used to fix the transplants during reconstruction of the PCL. Material and methods: A metallic landmark was placed on the centre of the femoral insertion of the two PCL strands in ten cadaver knees. The Metros software package was used to analyse the digitalised radiograms of each knee to determine the position of the strands on the medial condyle. Intra- and inter-observer variability was determined. Results: The AL strand was situated 31.6 + 2.45% (47.2 + 6.02% for the PM strand) from the anterior border of the notch or 41.18 + 2.73% (54.46 + 5.07% for the PM) from the anterior border of the medial condyle relative to the Blumensaat line and 16.12 + 4.45% (33.68 + 7.2 for the PM) from the apex of the notch. Discussion: Clinical and objective results of reconstruction depend on the ideal, basically femoral, position of the PCL insertions. Intraoperative identification of the ideal point for the femoral insertion can be improved with measurements made on cadaver knees. The values observed in the present study are reproducible. Presented in the form of percentages of length limiting the errors related to patient morphotype can be integrated into navigation systems

Purpose of the study: Total knee arthroplasty (TKA) is considered to be an effective treatment for degenerative knee joint disease when the functional impairment and the pain fail to respond to medical treatment. The success of TKA is determined by the degree of pain relief, functional recovery, and implant survival. For many years, those advocating or not preservation of the posterior cruciate ligament (PCL) have animated lively debates. Although a consensus has not been reached, posterior stabilised prostheses and prostheses with a mobile plateau are commonly implanted. The purpose of our study was to compare the outcomes obtained with fixed plateau TKA with preservation of the PCL with those obtained with other prostheses with or without sacrifice of the PCL with a fixed or mobile plateau. Material and methods: This was a prospective study in a single centre including a homogenous consecutive series of 12 TKA (cemented EUROP) with a fixed plateau and preservation of the PCL implanted from 1994 to 1996 in 117 patients aged 73 years on average. The International Knee Society scores were used for the clinical and radiographic assessment at ten years. Results: At ten years follow-up, 23 patients had died, 14 were lost to follow-up and 80 (82 knees) were evaluated clinically and 43 (45 knees) radiographically. The IKS knee score varied from 31 points (0–60) preoperatively to 88 points (30–98) postoperatively at last follow-up. The IKS function score was 40 points (0–90) preoperatively and 80 (25–100) at last follow-up. Lucent lines were noted for 59% of the condyles and 60% of the tibial plateaus. The lucencies were mainly located in the anterior and posterior zones of the femur (zones 1 and 4) and medially on the tibia (zones 1 and2). Two prostheses were revised at 8 and 11 years for loosening. The overall survival was 98.8% at ten years using the Kaplan-Meier method. Discussion: The clinical and radiological outcomes of prostheses with fixed plateaus and preserving the PCL in our series with one revision at 10 years were very satisfactory. Our results are comparable with earlier reports in the literature with or without sacrifice of the PCL with a fixed or mobile plateau. Conclusion: Longer term follow-up will be needed to confirm these results beyond ten years

Medial pivot total knee arthroplasty is designed to permit posterior rolling and sliding of the lateral femoral condyle around a stable medial femoral condyle. The purpose of the current study was to analyze the weight-bearing kinematics of medial pivot TKA’s with three different treatments of the posterior cruciate ligament: PCL resected, PCL partially released and PCL retained, to determine if the PCL status had a significant effect on tibiofemoral translations or rotations in a medial pivot TKA design. In vivo kinematics were determined for 17 clinically successful total knee arthroplasties during a stair-climbing activity using lateral fluoroscopy and shape matching techniques. All three groups showed similar medial pivot motions. PCL retained knees showed significantly greater tibial internal rotation than PCL resected knees for flexion of 30° and greater. Rotation of the PCL released knees was midway between PCL resected and PCL retained knees. Regardless of PCL treatment, patients with medial pivot total knee arthroplasties had medial pivot motion patterns during stair climbing activities. This study showed a clear and intuitive trend in motions with PCL-treatment, such that knees with partially released PCL’s had kinematics midway between those where the PCL was either fully maintained or fully resected

Introduction. Compared with the cruciate-retaining (CR) insert for total knee arthroplasty (TKA), the cruciate-substituting (CS) insert has a raised anterior lip, providing greater anterior constraint, and thus, can be used in cases of posterior cruciate ligament (PCL) sacrifice. However, studies have shown that the PCL maintains femoral rollback during flexion, acts as a stabilizer against distal traction force and aids knee joint proprioception; therefore, the argument for PCL excision in CS TKA remains controversial. The purpose of this study was to analyze CS TKA kinematics and identify the role of the PCL. Methods. Seven fresh-frozen lower-extremity cadaver specimens were analyzed using Orthomap. ®. Precision Knee Navigation software (Stryker Orthopaedics, Mahwah, NJ, USA). They were surgically implanted with Triathlon. ®. components (Stryker Orthopaedics). The CS insert has a raised anterior lip, and the posterior geometry shares the same profile as the CR, so we can choose retaining or sacrificing the PCL. Six patterns were analyzed: (1) natural knee; (2) only anterior cruciate ligament excision; (3) CS TKA, PCL retention, and bony island preservation; (4) CS TKA, PCL retention, and bony island resection; (5) CS TKA and PCL excision; and (6) CR TKA and PCL excision. Center of the knee and center of the proximal tibia were registered using navigation system, and the magnitudes of the condylar translation were evaluated. And then, using trigonometric function, the magnitude of anterior-posterior translation of the femur was calculated. Results. PCL excision patterns showed that the magnitude of anterior-posterior (AP) translation was higher in mid-flexion and lower in deep flexion than in other patterns (Fig. 1). Comparing two PCL excision patterns, in CS insert, the anterior translation magnitude was a little lower in extension and 30° flexion. Comparing two PCL retention patterns, the both posterior translation magnitudes in deep flexion were comparable to that of the natural knee. Discussion. Very few studies have reported about comparison of PCL retention with PCL excision in CS TKA. Omori et al. evaluated the medial pivot type TKA, and found that the design showed no femoral rollback under the PCL-sacrificing condition. In our study, increased anterior translation magnitudes in mid-flexion indicated paradoxical roll-forward, and decreased posterior translation magnitudes in deep flexion indicated decreased rollback. In other words, PCL excision in CS TKA caused mid-flexion instability and decreased the femoral rollback, so raised anterior lip was not likely to contribute to TKA kinematics. Another research is necessary to evaluate the effects of the raised anterior lip. On the other hand, PCL retention in CS TKA maintained physiological femoral rollback. The AP translation magnitude was not dependents on the bony island. Conclusions. We had better retain the PCL in raised anterior lip type CS TKA to ensure physiological knee kinematics. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction and Aims: The effects of injury to the posterior cruciate ligament (PCL) and posterior-lateral corner (PLC) on physical function are not as well documented compared to the more common injury to the anterior cruciate ligament. This study aimed at improving our understanding of PCL/PLC injury through gait analysis and electromyographic (EMG) testing. Method: We studied 19 patients, average age 30 years (20–55) with clinically and radiologically confirmed PCL/PLC deficiency in isolation. Ninety percent of patients complained of instability when performing the activities of daily living and all complained of pain. All patients were assessed using the Lysholm and Gillquist functional knee score as well as gait analysis, including Kinematics, Kinetics and EMG of the quadriceps, hamstrings and gastrocnemius muscles. Findings were compared to our normal database. The mean Lysholm score was 51/100 (24–90). Those with a Lysholm greater than 50 were designated as ‘copers’. Results: There were 12 ‘non-copers’ and seven ‘copers’. Fifty percent of patients demonstrated a varus thrust through stance. Forty-two percent of patients demonstrated hyperextension of the knee through stance. Sixty-three percent of patients demonstrated premature and prolonged hamstring activity. Thirty-seven percent of patients had premature activity of the gastrocnemius muscle in stance. Fifty-seven percent of the ‘copers’ demonstrated premature and prolonged hamstring activity through the gait cycle compared to forty-five percent of ‘non-copers’ (non-significant p=0.25 Fishers Exact Test). Fifty-five of ‘non-copers’ demonstrated premature activity of the gastrocnemius muscle in stance compared to none of the ‘copers’ (significant p=0.025 Fishers Exact Test). Conclusion: The observed varus thrust may be responsible for the development of medial and patellofemoral compartment osteoarthritis, a recognised problem in PCL deficient knees. Hyperextension that occurs dynamically during gait could explain failure of PCL/PLC reconstruction over time. The observed abnormal hamstrings activity is unlikely to be a compensatory mechanism

INTRODUCTION:. In varus knee, posterior cruciate ligament (PCL) release has been reported to result in the increase of the flexion gap without significant effect on the extension gap. However, the effect of release on gap angle is still obscure. On the other hand, gap angle and distance measured with the tension devices may vary due to different distraction forces. In this study, difference of gap angle and distance before and after PCL resection in knee extension and 90° flexion was inspected. Effect of different distraction force on gap was also assessed. OBJECTIVES:. Fifty cases with medial osteoarthritis undergoing PS-TKA were included in the study. PCL of all the cases were identified intact before resection. METHODS:. After distal femoral and proximal tibial cuts were initially performed and anterior cruciate ligament (ACL) was excised, joint gap angle and distance in full extension and at 90° flexion were obtained by means of a tensioning device, Balancer under 10, 20 and 30 inch-pounds distraction. The gap angle and distance were measured 3 times at each step. Then PCL was excised and the same measurement was performed. RESULTS:. The gap distances significantly enlarged following the increased distraction forces in both knee extension and 90° flexion, before and after the PCL resection (p < 0.0001). The distances were the same before and after the PCL resection in extension under each force. However, after the PCL was resected, the joint distance at 90° flexion significantly enlarged at 10, 20 and 30 inch-pounds for 1.2, 1.6 and 1.8 mm, respectively (p < 0.001). All measured joint gap angles showed varus results. The gap angles significantly increased following the increased distraction forces in both knee extension and 90° flexion, before and after the PCL resection (p < 0.0001). The mean gap angles in extension were 1.9°, 2.9° and 3.6° for 10, 20 and 30 inch-pounds, respectively. The angles significantly decreased after PCL resection in extension at different forces for 0.6°, 0.4° and 0.3°, respectively (p < 0.05). In 90° flexion, the mean angles were 2.9°, 5.5° and 7.3°, respectively, and were decreased after the resection for 0.3° (p = 0.9), 0.6° (p = 0.01) and 1.1° (p = 0.00024). CONCLUSION:. In this study, all the distances and angles had a correlation with the distraction powers of the tensioner. For the joint gap distance, the distance in extension was not influenced by the release of the PCL, but was enlarged at 90° flexion after the release. We found that the varus gap angles were decreased at both extension and flexion. Thirty inch-pounds seem to have more effect on the gap angle than 20 inch-pounds at 90° flexion after the release. It indicated that the evaluation of the joint gap might not be accurate if the distraction power of the tension device is not appropriate. Our study indicated that in varus deformity osteoarthritic knees, PCL resection may have influence on the correction of deformity. The means of modified gap control method and measured bone resection method, and the character of joint gap in CR, CS or PS TKA should be considered independently

Introduction. In posterior cruciate ligament (PCL)-preserving total knee arthroplasty (TKA), it is important to determine whether the PCL is properly functioning after surgery. As the PCL is partly damaged during the operation, we cannot rule out the possibility that excessive tension further damages the remaining PCL resulting in dysfunction or that initial functioning of the PCL is lost due to excessively low tension. However, it is normally difficult to examine whether the PCL has remained intact and is still functional after TKA. The objective of this study was to visualize knee joint flexion after TKA by MRI and evaluate the PCL based on these images. Method. PCL-preserving TKA was performed in 41 knees using the Fine Total Knee System® (Nakashima Medical, Okayama, Japan) where a titanium component can be selected for both the femur and the tibia. We visualized knee flexion positions by MRI at 6 months after surgery and evaluated visualization or non-visualization of the PCL, the relationship between knee flexion angle and PCL elevation angle against the plane of the tibial joint vertical to the tibial axis, and the forms of PCL based on the MRI data. Results. The PCL was visualized in 40 of the 41 knees. These 40 knees showed a strong positive correlation (correlation coefficient 0.85) between the knee flexion angle (mean 95.8 degrees, 59 to 129 degrees) and the PCL elevation angle (mean 60.4 degrees, 38 to 79 degrees) by MRI. As the PCL was visualized as a straight line in 6 of 13 knees at a knee joint flexion angle of less than 90 degrees, sufficient tension was considered to be transmitted; however, 7 knees showed superior protrusion or S-shaped forms, indicating that the tension in the PCL was not strong. No superior protrusion of the PCL was observed in 27 knees at the flexion angle of 90 degrees or more; 19 knees showed straight-line forms and 7 knees showed inferior protrusion due to posterior pressure from the femur, and the flexion angle was 105 degrees or greater in all knees with inferior protrusion. At the knee flexion angle of 90 degrees or greater, the tension in the PCL was confirmed in 26 knees (96%) by MRI. Conclusion. To date, there have been no morphological evaluations of postoperative PCL in PCL-preserving TKA. While tension in the PCL was determined to be insufficient in some knees at the knee flexion angle of less than 90 degrees, the elevation angle of the PCL against the tibia increased with tension as the knee flexion angle increased. Postoperative MRI indicated that the PCL functions as a stabilizer between the femur and the tibia in knees that have undergone PCL-preserving TKA, especially at the knee flexion angle of 90 degrees or greater

Purpose: Treatment of recent lesions of the posterior cruciate ligament (PCL) is not standardised. Decisions depend on the patients age and activity level, the degree of laxity, and the presence of combined lesions. Surgical solutions included PCL repair with suture, reconstruction with an autograft or allograft, or synthetic plasty. The purpose of this study was to analyse the results of synthetic reconstruction plasty for knees with important recent laxity of the PCL alone or in association with other lesions (triads, pentades, dislocations). We hypothesised that the synthetic ligament serves as a tutor guiding healing of the ruptured ligament. Material and methods: The series included 14 consecutive patients, 1 women, 13 men, mean age 27 years who were reviewed retrospectively. These patients were treated for isolated PCL tears (laxity > 15 mm) (n=3), PCL tears combined with laxity (medial or lateral) (n=6) or dislocation (n=5). Mean posterior laxity was 24 mm. The operation was performed 3 to 50 days after trauma using the LARS method (polyester ligament, 6 or 8 mm, 1 or 2 strands). All associated lesions were repaired during the same procedure except one A CL and one posterolateral angle which were treated secondarily. Mean follow-up was 36 months (10–88). All patients were seen for consultation except one who responded to a questionnaire. The IKDC score and Telos laxity measurements were noted. Results: In five knees, stiffness required mobilisation or arthroscopic arthrolysis. A secondary tear confirmed arthroscopically occurred in one case after a new trauma. Subjectively, two patients were very satisfied, eight were satisfied and three were disappointed. Final motion was: 6/0/130. Direct clinical posterior drawer was present in twelve cases: the Telos differential was 8 mm (24 mm preoperatively). The overall IKDC score was A=0, B=7, C=3, D=2. Persistent posterior laxity was the worst item. Outcome was less satisfactory for all items for posterolateral laxity. There was no difference between the one- and two-strand plasties. Discussion: We did not have any complications directly related to the synthetic ligament (synovitis, spontaneous tear). There was a significant gain in posterior laxity. Outcome depended on associated lesions, particularly lateral lesions (stiffness, IKDC score), rather than the surgical technique used to repair the PCL. The synthetic ligament appears to play its role as a tutor, a single strand measuring 6 mm in diameter is sufficient. Conclusion: This technique spares the tendon stock and can be proposed for recent tears of the PCL with major laxity. A longer term follow-up is needed to confirm the persistence of the improvement in laxity

Purpose of the study: The purpose of this study was to use weight-bearing radiographies to study the mobility of the polyethylene insert in relation to the femoral and tibial components of a total knee arthroplasty (TKA) with preservation of the posterior cruciate ligament and a mobile plateau with rotation and anterioposterior translation (INNEX. ®. Anterior-Posterior Glide, Zimmer). Material and methods: A 3D kinematic study of the femoral and tibial component and the mobile insert was conducted on a series of 51 first-intention TKA using a computer-assisted matching system between 3D prosthetic models and the radiographic silhouette of the implants. Results: At mean 23 months postoperatively, the poly-ethylene tibial insert exhibited an increase in its internal rotation during flexion. This rotation, knee extended, was limited to rotation between the insert and the tibial base. With increased flexion, there was an increase in the value and the portion of rotation involving the femoral component in relation with the mobile tibial insert. Discussion: The degree of insert mobility has varied depending on the report. Certain authors have reported relatively limited mobility because of a minimally congruent superior surface allowing anteroposterior and mediolateral translation as the femur glided over the insert. Others report mobility of the mobile plateau in relation to the tibial base and minimal rotation of the femoral component. Rotation of the polyethylene insert in TKAs with a mobile plateau appears to be quite variable. With the LCS AP Glide prosthesis, anteroposterior translation of the mobile plateau was measured at a mean 5.6 mm (1–1.125 mm). Paradoxical anterior translation, rather than posterior translation, of the mobile plateau with flexion has been reported in a few patients. Conclusion: The mobile plateau has exhibited progressive increase in internal rotation with flexion. We have concluded that the major part of the mobility occurs between the mobile plateau and the tibial base. However, with flexion, the femoral component increased its mobility over the plateau. During flexion, anteroposterior translation occurred between the femoral piece and the tibial insert, and between the tibial insert and the tibial base, but the direction of the translation of the mobile tibial insert appeared to be unpredictable with the non-constrained prosthesis used for this study

The influence of Posterior Cruciate Ligament (PCL) removal and re-establishment of the posterior condylar recess on flexion and extension gaps width during posterior-stabilized Total Knee Arthroplasty (TKA) is still controversial. It has been reported that PCL resection lead to a selective increase of the flexion space of 3–4 mm, creating a potential for instability in flexion. Our hypothesis was that these surgical steps will equally increase both gaps. Measurements of the flexion and extension gaps heights were obtained during different surgical phases in 50 consecutive primary posterior-stabilised TKAs using a tensor device and a calibrated torque wrench. There was a slight symmetrical increase in both gaps after PCL release. In extension the width of the gap increased on average 1.3 mm and 1.0 mm in the medial and lateral compartment respectively. The same pattern was observed in flexion, averaging 1.3 mm medially and 1.3 mm laterally. Another increase of the two gaps was observed after the posterior condylar osteophytes were removed and the posterior recess was re-established. The gaps in extension increased, with respect to the baseline value, on average 1.8 mm medially and 1.8 mm laterally, while in flexion the increase averaged 2.0 mm and 2.2 respectively on the medial and lateral side. Again there were no statistical differences between flexion and extension gaps. No independent differences between the flexion and extension gaps were found in any considered surgical phase. PCL removal and re-establishment of posterior condylar recess does not seem to require any additional consideration in gap balancing during posterior-stabilized TKA

Injuries to the posterior cruciate ligament (PCL) and the posterolateral corner (PLC) of the knee remain a challenging orthopaedic problem. Studies evaluating PCL and PLC reconstruction have failed to demonstrate a strong correlation between the degree of knee laxity as measured by uniplanar testing and subjective outcome or patient satisfaction. The effect that changing the magnitude of posterior tibial slope has on multiplanar, rotational stability of the PCL-deficient knee has yet to be determined. We aimed to evaluate the effect that changes in posterior tibial slope would have on static and dynamic stability of the PCL-PLC deficient knee. Ten knees were used for this study. Navigated posterior drawer and standardised reverse mechanised pivot shift maneuvers were performed in the intact knee and after sectioning the PCL, the lateral collateral ligament (LCL), the popliteofibular ligament (PFL) and the popliteus muscle tendon (POP). Navigated high tibial osteotomy (HTO) was performed to obtain the desired change in tibial plateau slope (+5® or −5® from native slope). We then repeated the posterior drawer and the reverse mechanised pivot shift test for each of the two altered slope conditions. Mean posterior tibial translation during the posterior drawer in the intact knee was 1.4 mm (SD = 0.48 mm). In the PCL-PLC deficient knee, posterior tibial translation increased to 18 mm (SD = 5.7 mm) (P < 0.001). Increasing the amount of posterior tibial slope by 5® reduced posterior tibial translation to 12 mm (SD = 4.7 mm) (P < 0.01). Decreasing the amount of posterior slope by 5® compared to the native knee, increased posterior tibial translation to 21 mm (SD = 6.8 mm) (P < 0.01). There was a significant negative correlation between the magnitude of tibial plateau slope and the magnitude of the reverse pivot shift (R2 = 0.71; P < 0.0001). Mean posterior tibial translation during the reverse mechanised pivot shift test in the intact knee was 7.8 mm (SD = 2.8 mm). In the PCL-PLC deficient knee, posterior tibial translation increased to 26 mm (SD = 5.6 mm) (P < 0.001). Increasing the amount of posterior tibial slope by 5® reduced posterior tibial translation to 21 mm (SD = 6.7 mm) (P < 0.01). Decreasing the amount of posterior slope by 5® compared to the native knee, increased posterior tibial translation to 34 mm (SD = 8.2 mm) (P < 0.01). There was a significant negative correlation between the magnitude of tibial plateau slope and the magnitude of the reverse pivot shift (R2 = 0.72; P < 0.0001). Decreasing the magnitude of posterior slope of the tibial plateau resulted in an increase in the magnitude of posterior tibial translation during the posterior drawer and the reverse mechanised pivot shift test in the PCL-PLC deficient knee. Conversely, increasing the slope of the tibial plateau reduced the amount of posterior tibial translation during the posterior drawer and the reverse mechanised pivot shift test. However, the effect of the increase in slope was not sufficient to reduce posterior tibial translation to levels similar to those of the intact knee

Purpose: Patellar complications are among the most frequent after total knee arthroplasty. Encasing the patellar piece is one way of resisting the shear forces leading to loosening. Material and Methods: We studied at more than five years the results obtained with a total knee prosthesis implanted with preservation of the posterior cruciate ligament (PCL). This prosthesis has an asymmetric encased patellar insert with a cemented central pivot. The instrumentation ensures patellar thickness. We reviewed 104 implants at more than five years. Six had been lost to follow-up. Ninety-eight implants were still in place. Results: The following complications were observed: four fractures of the upper rim with little displacement (these fractures healed and pain regressed but the insert had moved); three vertical patellar fractures with little displacement (these fractures healed; two were symptomatic temporarily); one transverse fracture of the upper pole with displacement causing a defect in active extension; eight moderate asymptomatic impactions which were visible on the lateral x-ray (modified orientation of the insert with cement fracture). There was no significant difference for functional results (pain 40.9; movement 21.9; knee score 84.3) between patients with or without a patellar complication. Discussion: Insertion of an asymmetric prosthesis increased the risk of an orientation error (two cases early in our experience). Encasing the patellar insert limits medialisation yet the centering was satisfactory (centred patella 95.2%, shift 3.6%, subluxation 1.2%). Encasing provides a peripheral wall protecting against transverse sheer forces. The lateral wall did not fracture, demonstrating its efficacy. The upper wall can fracture under the force of flexion without functional consequences. The other fractures, favoured by section of the lateral patellar wing (p< 0.05), were not treated. Moderate but certain impaction was noted in eight cases at a mean 3.5 years (1–6 years). It was due to failure of bony support under the effect of the compression forces applied on a small surface. The diameter of the encased patellar inserts was rarely more than 25 mm. Once the prosthesis is in place, the periphery of the patella is the only component articulating with the trochlea and its impaction does not cause further aggravation. This contact did not lead to pain in any patients. Conclusions: Complications observed with encased patellar components differ from the better known apposed prostheses

Purpose: Patellar complications are among the most frequent after total knee arthroplasty. Encasing the patellar piece is one way of resisting the shear forces leading to loosening. Material and methods: We studied at more than five years the results obtained with a total knee prosthesis implanted with preservation of the posterior cruciate ligament (PCL). This prosthesis has an asymmetric encased patellar insert with a cemented central pivot. The instrumentation ensures patellar thickness. We reviewed 104 implants at more than five years. Six had been lost to follow-up. Ninety-eight implants were still in place. Results: The following complications were observed: four fractures of the upper rim with little displacement (these fractures healed and pain regressed but the insert had moved); three vertical patellar fractures with little displacement (these fractures healed; two were symptomatic temporarily); one transverse fracture of the upper pole with displacement causing a defect in active extension; eight moderate asymptomatic impactions which were visible on the lateral x-ray (modified orientation of the insert with cement fracture). There was no significant difference for functional results (pain 40.9; movement 21.9; knee score 84.3) between patients with or without a patellar complication. Discussion: Insertion of an asymmetric prosthesis increased the risk of an orientation error (two cases early in our experience). Encasing the patellar insert limits medialisation yet the centering was satisfactory (centred patella 95.2%, shift 3.6%, subluxation 1.2%). Encasing provides a peripheral wall protecting against transverse sheer forces. The lateral wall did not fracture, demonstrating its efficacy. The upper wall can fracture under the force of flexion without functional consequences. The other fractures, favoured by section of the lateral patellar wing (p< 0.05), were not treated. Moderate but certain impaction was noted in eight cases at a mean 3.5 years (1–6 years). It was due to failure of bony support under the effect of the compression forces applied on a small surface. The diameter of the encased patellar inserts was rarely more than 25 mm. Once the prosthesis is in place, the periphery of the patella is the only component articulating with the trochlea and its impaction does not cause further aggravation. This contact did not lead to pain in any patients. Conclusions: Complications observed with encased patellar components differ from the better known apposed prostheses

Purpose of the study: Opinions vary concerning results after knee arthroplasty with preservation of the posterior cruciate ligament (PCL) in patients with rheumatoid disease. We report our findings in patients reviewed more than ten years after implantation in comparison with patients treated for osteoarthritis. Material and methods: One surgeon implanted 43 knee arthroplasites (Kali) with preservation of the PCL (9 bilateral cases) in 31 women and 3 men, mean age 53 years (range 30–70 years). Outcome was assessed with the AKS clinical and radiological scores. Passive recur-vatum and posterior drawer at 90° flexion were measured radiographicaly at last follow-up. Outcome was compared with the results observed in a control group of 29 prostheses of the same type implanted for osteoarthritis (among a total of 203 implantations). Results: There were no patients lost to follow-up: two patients were removed from the analysis due to infection on early wound necrosis and late metastatic infection. Eleven patients (16 prostheses) died before ten years follow-up; outcome was satisfactory for the prosthesis. Twenty-one patients (25 prostheses) were reviewed at more than ten years, mean follow-up 136 months. There was one case of supracondylar fracture which healed without sequela after osteosynthesis. The mean knee score was 34.3 preoperatively and 87.2 postoperatively with a mean function score improvement from 17 to 44 points. The pain score (47.3 points on average, was significantly improved while joint range of motion remained unchanged (117°). There were no worrisome lucent lines. Mean recurvatum measured radiographically was 6.9° (range 3–14°) and mean posterior drawer at 90° flexion was 4.2 mm. Outcome in the control group was the same excepting (p< 0.05) for lesser range of motion (109.7°) and better function score (62 points). Laxity (clinical and radiographic scores) were the same. Discussion: The results obtained in patients with rheumatoid disease were satisfactory and the same as those obtained in patients with osteoarthritis and were comparable to those with prostheses sacrificing and replacing the PCL. There were no cases of prosthesis loosening. Complications were very limited and less frequent than among the entire population of 203 prostheses for degenerative disease. Conclusion: Ligament alterations are not a contraindication for preservation of the PCL in patients with rheumatoid arthritis. Irrespective of the etiology, the main limitation on prosthesis longevity is polyethylene wear observed beyond ten years (ten changes of the plateau because of wear among 246 prostheses)

Purpose. To report clinical results and demonstrate any posterior femoral translation (PFT) in medial rotation total knee arthroplasty (TKA) of posterior cruciate ligament (PCL) retaining type. Materials and Methods. A prospective study was performed upon thirty consecutive subjects who were operated on with medial rotation TKA of PCL retaining type (Advance® Medial Pivot prosthesis with ‘Double High’ insert; Wright Medical Technology, Arlington, TN, USA) (Fig. 1). between March 2009 and March 2010 and had been followed up for a least 2 years. Inclusion criteria were age between 60 and 75 years and primary degenerative joint disease of knee graded as Kellgren Lawrence grade III or higher. Exclusion criteria were age under 60 years, any inflammatory joint disease including rheumatoid arthritis, early stage of primary degenerative joint disease of knee or any history of previous osteotomy around knee. Clinically, the knee society knee score and function score were used to evaluate pain and function. At last follow-up, all subjects performed full extension, thirty degree flexion and full active flexion sequentially under fluoroscopic surveillance. In each of these lateral radiographs, anteroposterior(AP) condylar position was pinpointed and the magnitude of PFT was determined by degree of transition of AP condylar position from full extension to full active flexion radiograph (Fig. 2 A–B). Statistical methods used were paired t-test, Pearson correlation, Steadman rank correlation and regression analysis. Component migration and radiolucent line were also observed. Results. At last follow-up, the mean knee society knee score and the mean function score improved significantly compared to preoperative scores (from 61.5 to 90.4 and from 57.8 to 84.7 respectively). The mean maximum flexion of knee increased postoperatively compared to preoperative one without any significant difference (105.5Ëš±11.2Ëšvs 109.3Ëš±9.8Ëš, p=0.051, β=0.387). Neverthless, regression analysis showed a good linear association (r = 0.53, p=0.0027) between the pre- and post-operative maximum flexions of knee. The AP condylar positions were consistently posterior to midline throughout the entire range of flexion. The mean maximum PFT was 10.5 mm (± 4.3 mm) and the magnitude of maximum PFT was greater in higher flexion cases (r = 0.57, p = 0.0009) (Fig. 3). There were no cases having either component migration or radiolucent line except for one case showing instability related to trauma. Conclusions. In medial rotation total knee arthroplasty of PCL retaining type, clinical outcomes were satisfactory and the maximum obtainable flexions tended to be in narrower ranges than those of preoperative ones and smaller than those of other TKA prostheses. Nonetheless, reliable posterior femoral translations were observed during progressive flexions of knees, which was considered to be one of important kinematic factors in increasing the level of knee flexion of medial-rotation TKA in longer follow-ups by providing greater posterior clearance and reduced femoro-tibial impingement

Most studies comparing medial pivot to the posterior stabilised (PS) systems sacrifice the PCL. It is unknown whether retaining the PCL in the Medial Congruent (MC) system may provide further benefit compared to the more commonly used PS system.

A retrospective review of a single-surgeon's registry data comparing 44 PS and 25 MC with PCL retained (MC-PCLR) TKAs was performed.

Both groups had similar baseline demographics in terms of age, gender, body mass index, and American Society for Anaesthesiology score. There was no significant difference in their preoperative range of motion (ROM) (104º±20º vs. 102º±20º,p=0.80), Oxford Knee Score (OKS) (27±6 vs. 26±7,p=0.72), and Knee Society Scoring System (KS) Function Score (KS-FS) (52±24 vs. 56±24,p=0.62). The preoperative KS Knee Score (KS-KS) was significantly lower in the PS group (44±14 vs. 54 ± 18,p<0.05). At 3-months postoperation, the PS group had significantly better OKS (38±6 vs. 36±6,p=0.02) but similar ROM (111º±14º vs. 108º±12º,p=0.25), KS-FS (73±20 vs. 68±23, p=0.32) and KS-KS (87±10 vs. 86±9,p=0.26). At 12-months postoperation, both groups had similar ROM (115º±13º vs. 115º±11º,p=0.99), OKS (41±5 vs. 40±5,p=0.45), KS-FS (74±22vs.78±17,p=0.80), and KS-KS (89±10vs.89±11,p=0.75). There was statistically significant improvement in all parameters at 1-year postoperation (p<0.05). The PS group had significant improvement in all parameters from preoperation to 3-month postoperation (p<0.05), but not from 3-month to 1-year postoperation (p≥0.05). The MC-PCLR group continued to have significant improvement from 3-month to 1-year postoperation (p<0.05).

The MC provides stability in the medial compartment while allowing a degree of freedom in the lateral compartment. Preserving the PCL when using MC may paradoxically cause an undesired additional restrain that slows the recovery process of the patients after TKA.

In conclusion, compared to MC-PCLR, a PS TKA may expect significantly faster improvement at 3 months post operation, although they will achieve similar outcomes at 1-year post operation.

A total of 22 patients with a tibial avulsion fracture involving the insertion of the posterior cruciate ligament (PCL) with grade II or III posterior laxity were reduced and fixed arthroscopically using routine anterior and double posteromedial portals. A double-strand Ethibond suture was inserted into the joint and wrapped around the PCL from anterior to posterior to secure the ligament above the avulsed bony fragment. Two tibial bone tunnels were created using the PCL reconstruction guide, aiming at the medial and lateral borders of the tibial bed. The ends of the suture were pulled out through the bone tunnels and tied over the tibial cortex between the openings of the tunnels to reduce and secure the bony fragment. Satisfactory reduction of the fracture was checked arthroscopically and radiographically.

The patients were followed-up for a mean of 24.5 months (19 to 28). Bone union occurred six weeks post-operatively. At final follow-up, all patients had a negative posterior drawer test and a full range of movement. KT-1000 arthrometer examination showed that the mean post-operative side-to-side difference improved from 10.9 mm (standard deviation (sd) 0.7) pre-operatively to 1.5 mm (sd 0.6) (p = 0.001). The mean Tegner and the International Knee Documentation Committee scores improved significantly (p = 0.001). The mean Lysholm score at final follow-up was 92.0 (85 to 96).

We conclude that this technique is convenient, reliable and minimally invasive and successfully restores the stability and function of the knee.

Cite this article: Bone Joint J 2015;97-B:1220–5.

129 knees suitable for a standard PCL retaining cemented total knee replacement were randomised into two groups, one in which PCL was retained in the normal way, the other group having the PCL fully resected. Both groups received a PCL retaining implant. The two groups were well matched with a predominance of females and a mean age of 67 years.

There was no statistically significant difference in the HSS scores at an average of 57 months (range 56–60 months) in the two groups. Pain relief, deformity correction, range of motion, stability and strength were comparable in the two groups. A radiological assessment revealed femoral rollback in approximately 20% of cases with a slightly higher incidence in the PCL sacrificed group. There was no significant loosening detected in either of the categories at two years review.

At five years one TKR in the PCL retained group has been revised due to an infection and one each in the two groups are awaiting revision surgery for loosening. Our findings have shown that there is no significant difference in the 5 year results of a PCL-retaining total knee replacement if the PCL is excised or preserved. This suggests two significant points:

the PCL is not functional in most patients with a total knee replacement even when retained:

We randomised 129 knees which were to be replaced using a standard posterior-cruciate-ligament (PCL)-retaining cemented total knee replacement into two groups. In one the PCL was retained in the normal way and in the other it was resected. They were well matched, with a predominance of women, and a mean age of 67 years.

There was no statistically significant difference in the Hospital for Special Surgery scores at a mean of 57 months (56 to 60) between the two groups although 21 patients (24 knees) were lost to follow-up. Relief from pain, correction of deformity, range of movement, stability and strength were comparable in both. Radiological assessment showed femoral rollback in approximately 20% of knees with a slightly higher incidence in the PCL-resected group. There was no significant loosening detected in either group at review at two years.

At five years, one knee in the PCL-retained group had been revised because of infection and one patient in each group was awaiting revision for loosening.

Our findings have shown no significant difference in the five-year results for a PCL-retaining total knee replacement if the PCL is excised or preserved. This suggests two important points. First, the PCL is not functional in most patients with a total knee replacement even when retained. Secondly, patients with an excised PCL show a good result with a PCL-retaining implant, thereby questioning the need for a posterior stabilised design in such a situation.

Aims: We performed a prospective randomised controlled clinical trial of a comparison of PCL excison and PCL retention whilst using a standard PCL retaining cemented PFC knee relacement in order to answer two questionsòa) is the PCL functional if retained in PCL retaining TKRs. b) does PCL excison affect the results of a standard PCL retaining knee replacement. Methods: 129 knees suitable for a standard PCL retaining cemented total knee replacement were randomised into two groups, one in which the PCL was retained in the normal way, the other group having the PCL fully resected. Both groups received a PCL retaining implant. The two groups were well matched with a predominance of females and a mean age of 67 years. Results: There was no statistically significant difference in the HSS scores at an average of 57 months in the two groups. Pain relief, deformity correction, range of motion, stability and strength were comparable in the two groups. A radiological assessment revealed significant rollback in approximately 20% of cases with a slightly higher incidence in the PCL sacrificed group. There was no significant loosening detected in either of the categories at two years review. At five years one TKR in the PCL retained group has been revised due to an infection and one each in the two groups are awaiting revison surgery for loosening. Conclusions: Our findings have shown that there is no significant difference in the 5 year results of a PCL retaining total knee replacement if the PCL is excised or preserved. This suggests two significant points –a) the PCL is not functional in most patients with a total knee replacement even when retained. b) patients with excised PCLs show good results with PCL retaining implants, thereby questioning the need for posterior stabilised designs in all such cases.

Purpose: The aim of this study was to elucidate the continiuty of ligament in chronic injury of the posterior cruciate ligament(PCL).

Method: Magnetic resonance imaging(MRI) of twenty-six PCL injury patients with grade II or III laxity and more than 5mm side to side difference on stress radiographs were reviewed in terms of ligamentous continuity and thickness of the ligament at average 7.2 months(range:1–36) after injury. The results were compared with arthroscopic findings in fifteen patients.

Results: Eighteen PCLs(69%) showed continuity of PCL, in which average thickness of the injured portion was 61% of the intact portion. When thickness of the ligament in cases without continuity was rated as zero, the average thickness of the PCLs as compared to intact portion of the ligament increased as the time from injury elapsed; 16.4% in 0–2 months group (7 cases), 30.0% in 3–5 months group (6 cases), 53.8% in 6–8 months group (9 cases) and 80.0% in over 9 months group (4 cases). Of the fifteen cases with confirmed continuity of PCL in arthroscopic examination, nine cases showed continuity on MRI, while the remaining six cases didn’t.

Conclusion: More than two thirds of PCLs in symptomatic chronic injury showed ligamentous continuity on MRI. The longer the interval from injury was, the thicker the PCL was. In cases over 6 months after injury, the PCLs were of more than 50% thickness of the intact portion.

Introduction

The objective of this study was to assess the effect of PCL resection on flexion-extension gaps, mediolateral soft tissue laxity, fixed flexion deformity (FFD), and limb alignment during posterior-stabilised total knee arthroplasty (TKA).

INTRODUCTION

Contemporary PCL sacrificing Total Knee Arthroplasty (TKA) implants (CS) consist of symmetric medial and lateral tibial articular surfaces with high anterior lips designed to substitute for the stability of the native PCL. However, designs vary significantly across implant systems in the level of anteroposterior constraint provided. Therefore, the goal of this study was to investigate kinematics of two CS designs with substantially different constraint levels. The hypothesis was that dynamic knee simulations could show the effect of implant constraint on kinematics of CS implants.

Purpose: A pre- and postoperative radiographic analysis of 50 total knee arthroplasties (TKA) was performed to determine the femorotibial correction angle and the tibial and femoral mechanical angles obtained as a function of the initial bony deformity. The preoperative angle beyond which correction was not achieved was determined.

Material and methods: This prospective single-centre study included 50 TKA (25 men and 25 women), mean age 69.1 years (range 53–83). Degenerative disease involved the right knee in 21 cases and the left knee in 29. A Wallaby I TKA (semi-restrained with preservation of the posterior cruciate ligament) was implanted in all cases. Three angles were calculated on the AP loaded knee: AFT (femorotibial angle), AFM (femoral mechanical angle), ATM (tibial mechanical angle). For each angle, statistic analysis was performed on four groups of patients: group I: overall population, group II: patients with normal axis (178°< AFT< 182°; 88°< AFM< 92°; 88)< ATM< 92°), group III: patients with varus (AFT> 182°; AFM> 92°; ATM> 92°), and group IV: patients with valus (AFT< 178°; AFM< 88°; ATM< 88°). Non-parametric tests (Spearman rank test and MacNemar symmetry test) were performed on SAS software for statistical analysis with p< 0.05 considered as significant.

Results: Pre- and postoperative AFT showed: significant improvement of the mean (> 3.44° in group I, > 6.87° in group III, and > 6.12° in group IV). There was no significant difference in group II. Pre- and postoperative AFM showed: constant but non-significant improvement in groups I and III (> 3°) and constant and significant improvement in groups III and IV (> 2.5°). Pre- and postoperative ATM showed: significant improvement in groups I and III (> 3°), constant but non-significant improvement in group IV (n=4). There was no group II. An ATM > 94° was the threshold angle beyond which correction was not obtained.

Discussion: Taken together, the results of this study confirm the reliability of the Wallaby I instrumentation for achieving a correct postoperative mechanical axis. These results are comparable with data in the literature (with or without preservation of the posterior cruciate ligament). However, the correction of the bony deformity obtained depended uniquely on the initial deformity of the tibia. Extreme deformity of the tibia should be corrected with osteotomy or with a more restrained prosthesis.

Balancing the PCL in a PCL-retaining total knee replacement (TKR) is important, but sometimes difficult to execute in an optimal manner. Due to the orientation of the PCL it is conceivable that flexion gap distraction will lead to anterior movement of the tibia relative to the femur. This tibio-femoral repositioning influences the tibio-femoral contact point, which on its turn affects the kinematics of the TKR. So far, the amount of tibiofemoral repositioning during flexion gap distraction is unknown which leads to uncertain kinematic effects after surgery. The goal of this study was to quantitatively describe the parameters of the flexion gap (gap height, anterior tibial translation and femoral rotation) and their relationship while the knee is distracted during implantation of a PCL-retaining TKR with the use of computer navigation. Furthermore, the effect of PCL elevation angle on the flexion gap parameters was determined.

In 50 knees, during a ligament-guided TKR procedure, the flexion gap was distracted with a double-spring tensor with 100 and 200 N after the tibia had been cut. The flexion gap height, anterior tibial translation and femoral rotation were measured intra-operatively using a CT-free navigation system. PCL elevation was calculated based on the femoral and tibial insertion sites as indicated by the surgeon with the pointer of the navigation system.

To identify a relationship between flexion gap height increase and anterior tibial translation, the ratio between anterior translation and gap height increase was determined for each patient between 100 and 200 N.

The mean gap height increased 2.2 mm (SD 0.96) and mean increase in anterior tibial translation was 4.2 mm (SD 1.6). Hence, on average, for each mm increase in gap height, the tibia moved 1.9 mm (SD 0.96) in anterior direction. Knees with a steep PCL showed significantly more AP translation for each mm gap height increase (gap/AP-ratio was 1 : 2.31 (SD 0.63)) compared to knees with a flat PCL (gap/AP-ratio was 1 : 1.73 (SD 0.50)).

The increase in femur (exo)rotation was on average 0.60° (SD 1.4).

With a tensioned PCL the tibia will move anteriorly on average 1.9 mm for every extra mm that the flexion gap is increased. The flexion gap dynamics can be explained in part by the orientation of the PCL: the greater the elevation angle, the more anterior tibial displacement during distraction of the flexion gap. The surgeon must be aware that distraction of the flexion gap influences the tibiofemoral contact point. The tibio-femoral contact point will move posteriorly and stresses in the PCL will rise and produce limited flexion and pain. In case of a conforming insert AP-movement will be limited but high PE stresses may be introduced that can lead to wear. This information may be helpful in selecting the optimal soft tissue balancing procedure and the optimal PE insert thickness in PCL retaining TKR.

Introduction and Aims: To assess the tibiofemoral kinematics of the PCL deficient knee using vertical open-access ‘dynamic’ MRI.

Method: Tibiofemoral motion was assessed using open-access MRI, weight-bearing in a squat, through the arc of flexion from zero to 90 degrees in six patients with isolated rupture of the PCL in one knee [diagnosed from conventional MRI scanning and clinical assessment] and a normal contralateral knee. Mid-medial and mid-lateral sagittal images were analysed in all chosen positions of flexion in both knees to assess the relative tibiofemoral relationships. Passive sagittal laxity was assessed by performing the posterior and anterior drawer tests, while the knees were scanned, again using the same MRI scanner. The tibiofemoral positions during this stress MRI examination was measured from mid-medial and mid-lateral sagittal images of the knees.

Results: Rupture of the PCL leads to an increase in passive sagittal laxity in the medial compartment of the knee [P< 0.006]. In the weight-bearing scans, PCL rupture alters the kinematics of the knee with persistent posterior subluxation of the medial tibia so that the femoral condyle rides up the anterior upslope of the medial tibial plateau. This ‘fixed’ subluxation was observed throughout the extension-flexion arc being statistically significant at all flexion angles (P< 0.018 at 0°, P< 0.013 at 20°, P< 0.014 at 45°, P< 0.004 at 90°). The kinematics of the lateral compartment were not altered by PCL rupture to a statistically significant degree. The posterior drawer test showed increased laxity in the medial compartment.

Conclusion: PCL rupture alters the kinematics of the medial compartment of the knee resulting in ‘fixed’ anterior subluxation of the medial femoral condyle [posterior subluxation of the medial tibial condyle]. This study helps to explain the observation of increased incidence of osteoarthritis in the medial compartment and specifically femoral condyle, in PCL deficient knees.

We evaluated the accuracy of six clinical tests for posterior instability in 24 knees with acute surgically-proven posterior cruciate ligament injuries and intact anterior cruciate ligaments. We also performed stress radiography under anaesthesia. The gravity sign and the posterior drawer test in near extension and its passive reduction were diagnostic in 20 of the 24 knees, and the active reduction of posterior subluxation was diagnostic in 18. The reversed pivot shift sign helped to diagnose severe posterior and posterolateral subluxations, but the external rotation recurvatum test was negative in all 24 knees. Stress radiography in near extension revealed a highly significant increase in posterior tibial subluxation in the injured knees.

Introduction

Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femolo-tibial joint as well as posterior-stabilized (PS) polyethylene insert, even if PCL is sacrificed after TKA. The purpose of this study is an investigation of in vivo kinematics of femolo-tibial joint with use of CS polyethylene insert before and after PCL resction using computer assisted navigation system intra-operatively in TKA.

Purpose: The purpose of this study is to compare the clinical results of a standard polyethylene tibial insert versus the high flex polyethylene tibial insert component designs of a posterior cruciate substituting total knee replacement.

Method: One-hundred patients were entered into a prospective, randomized clinical trial comparing standard polyethylene tibial inserts versus the high flex polyethylene tibial insert component designs of posterior cruciate substituting total knee replacement(Genesis II, Smith & Nephew, Memphis, TN). Patients were evaluated pre-operatively, at 3, 12 months and annually thereafter. Patient demographics, radiographs, and multiple outcome measures (WOMAC, SF-12 and the Knee Society Clinical Rating System) were evaluated.

Results: No patients were lost to follow-up. One patient died prior to the two year follow up. Ninety- nine patients were reviewed at an average follow-up of 2.7 years (range 2.3 – 3.1 years). There were no significant differences in any outcome measures or radiographic findings. There were no differences in KSCRS at two years (Standard − 170, High Flex −171). There were no differences in knee flexion at 2 years (Standard− 125°, High Flex − 126°).

Conclusion: In this prospective randomized clinical trial, no differences could be seen between standard polyethylene and a “Hi- Flex” polyethylene design at a minimum of 2 years follow-up. In particular, no improvement in knee flexion was observed. Long-term evaluation will be required to comment on differences in polyethylene wear and implant longevity.

Aims. The aim of this study was to screen the entire genome for genetic markers associated with risk for anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injury. Methods. Genome-wide association (GWA) analyses were performed using data from the Kaiser Permanente Research Board (KPRB) and the UK Biobank. ACL and PCL injury cases were identified based on electronic health records from KPRB and the UK Biobank. GWA analyses from both cohorts were tested for ACL and PCL injury using a logistic regression model adjusting for sex, height, weight, age at enrolment, and race/ethnicity using allele counts for single nucleotide polymorphisms (SNPs). The data from the two GWA studies were combined in a meta-analysis. Candidate genes previously reported to show an association with ACL injury in athletes were also tested for association from the meta-analysis data from the KPRB and the UK Biobank GWA studies. Results. There was a total of 2,214 cases of ACL and PCL injury and 519,869 controls within the two cohorts, with three loci demonstrating a genome-wide significant association in the meta-analysis: INHBA, AEBP2, and LOC101927869. Of the eight candidate genes previously studied in the literature, six were present in the current dataset, and only COL3A1 (rs1800255) showed a significant association (p = 0.006). Conclusion. Genetic markers in three novel loci in this study and one previously-studied candidate gene were identified as potential risk factors for ACL and PCL injury and deserve further validation and investigation of molecular mechanisms. Cite this article: Bone Jt Open 2021;2(6):414–421

Introduction There are only a limited number of long term studies of total knee arthroplasty but none with a minimum 15 year survivorship of a modular fixed bearing posterior cruciate-retaining prosthesis.

Methods We present a consecutive series of 139 total knee arthroplasties (109 patients, average age 67 years), using a non-conforming posterior cruciate-retaining prosthesis, followed for a minimum of 15 years (range, 15.0 to 16.9 years). The patella was resurfaced with an all-polyethylene component in 83% of knees. The tibial component was always cemented, while a porous coated femoral component was used in 84% of knees. Fortyfive patients (59 knees) were followed-up for a minimum of 15 years, 57 (70 knees) had died, five patients (8 knees) were too ill to assess, two patients (two knees) were considered lost to follow-up.

Results In this series there were five re-operations, four of which were for polyethylene insert wear. At two of these, the patella was exchanged for early surface wear and one patella was resurfaced for the first time. There was one loose cemented femoral component after more than 15 years. The survival without revision or need for revision for any reason was 99% at 10 years and 95.6% (worst case scenario of 94.2%) at 15 years. The mean Knee Society Score and Function Score at 15 year follow-up was 96 and 78 respectively. The total incidence of radiolucent lines was 13%, with two percent around the femur, 11% around the tibia and zero percent around the patella. None of these lines were of any clinical relevance. There was no evidence of progressive radiolucent lines or component loosening, and one case of zone four femoral osteolysis.

Conclusions This single-surgeon series with a minimum 15 year follow-up, and excellent clinical, radiological and survivorship results provides a benchmark upon which other long term studies of modular fixed bearing posterior cruciate retaining total knee arthroplasty can be compared.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.

Aim: To compare the ability of two different PLC reconstruction techniques to restore the kinematics of a PCL & PLC deficient knee to PCL deficient condition.

Methods: 8 fresh frozen cadaver knees were used. A custom rig with electromagnetic tracking system measured knee kinematics. Each knee was tested with posterior & anterior drawer forces of 80N, external rotation moment of 5Nm & varus moment of 5Nm when intact, after dividing PCL, PLC (lateral collateral ligament & popliteus tendon), after PLC reconstruction type1 (1PLC) & PLC reconstruction type 2 (2PLC). 1PLC was modification of Larson’s technique with semitendinosus graft. 2PLC was performed with semitendinosus graft to reconstruct the lateral collateral ligament & the pop-liteofibular ligament, gracillis used to reconstruct pop-liteus tendon.

Results: The one-tailed paired student’s t test with Bon-ferroni correction was used to analyse the data. Only in deep flexion 2PLC reconstruction was significantly better than the 1PLC reconstruction in restoring the posterior laxity to PCL deficient condition (p=0.02). (Figure1) In deep flexion 1PLC could not restore the rotational laxity to PCL deficient condition (p=0.02). In mid flexion the 2PLC was unable to restore the rotational laxity to PCL deficient condition (p=0.048) (Figure 2).

Conclusion: The 2PLC reconstruction was better than the 1PCL in controlling the posterior drawer. The 1PLC technique though not significant tended to over constrain the external & varus rotations.

The posterior drawer is a commonly used test to diagnose an isolated PCL injury and combined PCL and PLC injury. Our aim was to analyse the effect of tibial internal and external rotation during the posterior drawer in isolated PCL and combined PCL and PLC deficient cadaver knee.

Ten fresh frozen and overnight-thawed cadaver knees with an average age of 76 years and without any signs of previous knee injury were used. A custom made wooden rig with electromagnetic tracking system was used to measure the knee kinematics. Each knee was tested with posterior and anterior drawer forces of 80N and posterior drawer with simultaneous external or internal rotational torque of 5Nm. Each knee was tested in intact condition, after PCL resection and after PLC (lateral collateral ligament and popliteus tendon) resection. Intact condition of each knees served as its own control. One-tailed paired student's t test with Bonferroni correction was used.

The posterior tibial displacement in a PCL deficient knee when a simultaneous external rotation torque was applied during posterior drawer at 90° flexion was not significantly different from the posterior tibial displacement with 80N posterior drawer in intact knee (p=0.22). In a PCL deficient knee posterior tibial displacement with simultaneous internal rotation torque and posterior drawer at 90° flexion was not significantly different from tibial displacement with isolated posterior drawer. In PCL and PLC deficient knee at extension with simultaneous internal rotational torque and posterior drawer force the posterior tibial displacement was not significantly different from an isolated PCL deficient condition (p=0.54).

We conclude that posterior drawer in an isolated PCL deficient knee could result in negative test if tibia is held in external rotation. During a recurvatum test for PCL and PLC deficient knee, tibial internal rotation in extension results in reduced posterior laxity.

The aim of this study was to compare the maximum laxity conferred by the cruciate-retaining (CR) and posterior-stabilised (PS) Triathlon single-radius total knee arthroplasty (TKA) for anterior drawer, varus–valgus opening and rotation in eight cadaver knees through a defined arc of flexion (0º to 110º). The null hypothesis was that the limits of laxity of CR- and PS-TKAs are not significantly different.

The investigation was undertaken in eight loaded cadaver knees undergoing subjective stress testing using a measurement rig. Firstly the native knee was tested prior to preparation for CR-TKA and subsequently for PS-TKA implantation. Surgical navigation was used to track maximal displacements/rotations at 0º, 30º, 60º, 90º and 110° of flexion. Mixed-effects modelling was used to define the behaviour of the TKAs.

The laxity measured for the CR- and PS-TKAs revealed no statistically significant differences over the studied flexion arc for the two versions of TKA. Compared with the native knee both TKAs exhibited slightly increased anterior drawer and decreased varus-valgus and internal-external roational laxities. We believe further study is required to define the clinical states for which the additional constraint offered by a PS-TKA implant may be beneficial.

Cite this article: Bone Joint J 2015; 97-B:642–8.

Aims. A functional anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) has been assumed to be required for patients undergoing unicompartmental knee arthroplasty (UKA). However, this assumption has not been thoroughly tested. Therefore, this study aimed to assess the biomechanical effects exerted by cruciate ligament-deficient knees with medial UKAs regarding different posterior tibial slopes. Methods. ACL- or PCL-deficient models with posterior tibial slopes of 1°, 3°, 5°, 7°, and 9° were developed and compared to intact models. The kinematics and contact stresses on the tibiofemoral joint were evaluated under gait cycle loading conditions. Results. Anterior translation increased in ACL-deficient UKA cases compared with intact models. In contrast, posterior translation increased in PCL-deficient UKA cases compared with intact models. As the posterior tibial slope increased, anterior translation of ACL-deficient UKA increased significantly in the stance phase, and posterior translation of PCL-deficient UKA increased significantly in the swing phase. Furthermore, as the posterior tibial slope increased, contact stress on the other compartment increased in cruciate ligament-deficient UKAs compared with intact UKAs. Conclusion. Fixed-bearing medial UKA is a viable treatment option for patients with cruciate ligament deficiency, providing a less invasive procedure and allowing patient-specific kinematics to adjust posterior tibial slope. Patient selection is important, and while AP kinematics can be compensated for by posterior tibial slope adjustment, rotational stability is a prerequisite for this approach. ACL- or PCL-deficient UKA that adjusts the posterior tibial slope might be an alternative treatment option for a skilled surgeon. Cite this article: Bone Joint Res 2022;11(7):494–502

Aims. This study compared patient-reported outcomes of three total knee arthroplasty (TKA) designs from one manufacturer: one cruciate-retaining (CR) design, and two cruciate-sacrificing designs, anterior-stabilized (AS) and posterior-stabilized (PS). Methods. Patients scheduled for primary TKA were included in a single-centre, prospective, three-armed, blinded randomized trial (n = 216; 72 per group). After intraoperative confirmation of posterior cruciate ligament (PCL) integrity, patients were randomly allocated to receive a CR, AS, or PS design from the same TKA system. Insertion of an AS or PS design required PCL resection. The primary outcome was the mean score of all five subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) at two-year follow-up. Secondary outcomes included all KOOS subscales, Oxford Knee Score, EuroQol five-dimension health questionnaire, EuroQol visual analogue scale, range of motion (ROM), and willingness to undergo the operation again. Patient satisfaction was also assessed. Results. Patients reported similar levels of pain, function, satisfaction, and general health regardless of the prosthetic design they received. Mean maximal flexion (129° (95% confidence interval (CI) 127° to 131°) was greater in the PS group than in the CR (120° (95% CI 121° to 124°)) and AS groups (122° (95% CI 120° to 124°)). Conclusion. Despite differences in design and constraint, CR, AS, and PS designs from a single TKA system resulted in no differences in patient-reported outcomes at two-year follow-up. PS patients had statistically better ROM, but the clinical significance of this finding is unclear. Cite this article: Bone Joint J 2023;105-B(12):1271–1278

Instability currently represents the most frequent cause for revision total knee replacement. Instability can be primary from the standpoint of inadequately performed collateral and/or posterior cruciate ligament balancing during primary total knee replacement or it may be secondary to malalignment secondary to loosening and settling of the implants which can develop later progressive instability. Revision surgery must take into consideration any component malalignment that may have primarily contributed to instability. Also, collateral ligament integrity may change following total knee replacement slightly after complete correction of a severe deformity that presents rarely as instability after several months. Care should be given to assessing collateral ligament integrity. This can be done during physical examination by manual or radiological stress testing to see if the mediolateral stress of the knee comes to a good endpoint. If there is no sense of a palpable endpoint, then the surgeon must assume structural incompetency of the medial or lateral collateral ligament or both. In posterior cruciate ligament retaining knees, anteroposterior instability must be assessed. For instability, most revisions will require a posterior cruciate substituting design or a constrained unlinked condylar design. Occasionally, a posterior cruciate ligament preserving design can be used in situations where the bone-stock is well preserved and the posterior cruciate ligament shows excellent structural integrity. However, if the patient displays considerable global instability, a linked, rotating platform constrained total knee replacement design will be required. Recent data has shown that the rotating hinges work quite well in restoring stability to the knee with maintenance of the clinical results over a considerable length of time. Revision can range from simple polyethylene insert exchange to a thicker dimension, isolated component revision or complete revision of both femoral and tibial devices. During revision surgery, laminar spreaders may be utilised to assess the flexion and extension spaces after the tibial platform is restored. If a symmetric flexion and extension space is achieved, then the collateral ligaments are intact. Depending on the remaining existing bone stock, a posterior stabilised or constrained condylar unlinked prosthesis may be used for implantation. In cases with considerable asymmetry or a large flexion/extension mismatch, a rotating hinge design should be utilised. Intramedullary stems should be utilised in most cases when bone integrity is suspect and insufficient. Currently, stems should be placed cementless to permit easier future revision. Cementing the stems is only recommended if there is lack of intramedullary isthmic support or there is a hip prosthetic stem that prohibits a stem from engaging the isthmic cortex. However, it should be realised that later revision of the fully cemented revision implant may be quite difficult. Infection should be ruled out by aspiration off of antibiotics prior to any revision operation, especially if loosening of the components represents the cause of instability early. The surgeon should attempt to restore collateral ligament balance whenever possible as this yields the best clinical result

Aims. Unicompartmental knee arthroplasty (UKA) has become a popular method of treating knee localized osteoarthritis (OA). Additionally, the posterior cruciate ligament (PCL) is essential to maintaining the physiological kinematics and functions of the knee joint. Considering these factors, the purpose of this study was to investigate the biomechanical effects on PCL-deficient knees in medial UKA. Methods. Computational simulations of five subject-specific models were performed for intact and PCL-deficient UKA with tibial slopes. Anteroposterior (AP) kinematics and contact stresses of the patellofemoral (PF) joint and the articular cartilage were evaluated under the deep-knee-bend condition. Results. As compared to intact UKA, there was no significant difference in AP translation in PCL-deficient UKA with a low flexion angle, but AP translation significantly increased in the PCL-deficient UKA with high flexion angles. Additionally, the increased AP translation became decreased as the posterior tibial slope increased. The contact stress in the PF joint and the articular cartilage significantly increased in the PCL-deficient UKA, as compared to the intact UKA. Additionally, the increased posterior tibial slope resulted in a significant decrease in the contact stress on PF joint but significantly increased the contact stresses on the articular cartilage. Conclusion. Our results showed that the posterior stability for low flexion activities in PCL-deficient UKA remained unaffected; however, the posterior stability for high flexion activities was affected. This indicates that a functional PCL is required to ensure normal stability in UKA. Additionally, posterior stability and PF joint may reduce the overall risk of progressive OA by increasing the posterior tibial slope. However, the excessive posterior tibial slope must be avoided. Cite this article: Bone Joint Res 2020;9(9):593–600

Aims. Little is known about the risk factors that predispose to a rupture of the posterior cruciate ligament (PCL). Identifying risk factors is the first step in trying to prevent a rupture of the PCL from occurring. The morphology of the knee in patients who rupture their PCL may differ from that of control patients. The purpose of this study was to identify any variations in bone morphology that are related to a PCL. Patients and Methods. We compared the anteroposterior (AP), lateral, and Rosenberg view radiographs of 94 patients with a ruptured PCL to a control group of 168 patients matched by age, sex, and body mass index (BMI), but with an intact PCL after a knee injury. Statistical shape modelling software was used to assess the shape of the knee and determine any difference in anatomical landmarks. Results. We found shape variants on the AP and Rosenberg view radiographs to be significantly different between patients who tore their PCL and those with an intact PCL after a knee injury. Overall, patients who ruptured their PCL have smaller intercondylar notches and smaller tibial eminences than control patients. Conclusion. This study shows that differences in the shape of the knee are associated with the presence of a PCL rupture after injury. A smaller and more sharply angled intercondylar notch and a more flattened tibial eminence are related to PCL rupture. This suggests that the morphology of the knee is a risk factor for sustaining a PCL rupture. Cite this article: Bone Joint J 2019;101-B:1058–1062

Introduction. The range of motion (ROM) obtained after total knee arthroplasty (TKA) is an important measurement to evaluate the postoperative outcomes impacting other measures such as postoperative function and satisfaction. Flexion contracture is a recognized complication of TKA, which reduces ROM or stability and is a source of morbidity for patients. Objectives. The purpose of this study was to evaluate the influence of intra-operative soft tissue release on correction of flexion contracture in navigated TKA. Methods. This is prospective cohort study, 43 cases of primary navigation assisted TKA were included. The mean age was 68.3 ± 6.8 years. All patients were diagnosed with grade 4 degenerative arthritis in K-L grading system. The average preoperative mechanical axis deviation was 10.3° ± 5.3 and preoperative flexion contracture was 12.8° ± 4.8. All arthroplasties were performed using a medial parapatellar approach with patellar subluxation. First, medial release was performed, and posterior cruciate ligament was sacrificed. After all bone cutting was performed and femoral and tibial trials were inserted, removal of posterior femoral spur and capsular release were performed. The degree of correction of flexion contracture was evaluated and recorded with navigation. Results. After the medial soft tissue release, as a first step, the flexion contracture was recorded as 7.2° ± 4.3 and 4.1° ± 4.0 as varus. The second step, posterior cruciate ligament was sacrificed, the flexion contracture was recorded as 7.2° ± 4.4 and 5.5° ± 3.0 as varus. After posterior clearing procedure and capsular release, the flexion contracture was showed as 3.9° ± 1.2 and 1.4° ± 1.2 as varus. The final angles after cemented real implant were recorded as 3.3° ± 1.4 in flexion contracture, 0.9° ± 1.8 in varus. There were significant differences all steps except between medial release step and posterior cruciate sacrifice step and between posterior clearing step and final angle. Conclusions. The appropriate soft tissue balancing could correct flexion contracture intra-operatively. The medial release could correct the flexion contracture around 5° compared with preoperative flexion contracture, and posterior clearing procedure could improve further extension. However, the sacrifice of posterior cruciate ligament provided little effect on correction of the flexion contracture intra-operatively

Knee arthroscopy is typically approached from the anterior, posteromedial and posterolateral portals. Access to the posterior compartments through these portals can cause iatrogenic cartilage damage and create difficulties in viewing the structures of the posterior compartments. The purpose of this study was to assess the feasibility of needle arthroscopy using direct posterior portals as both working and visualising portals. For workability, the needle scope was inserted advanced from anterior between the cruciate ligament bundle and the lateral wall of the medial femoral condyle until the posterior compartments were visualised. For visualisation, direct postero-lateral and -medial portals were established. The technique was performed in 9 knees by two experienced researchers. Workability and instrumentation of the posteromedial compartment and meniscus was achieved in 56%. The posterior horns could not be visualised in four specimens as the straight lens could not provide a more medial field of view. Visualisation from the direct medial posterior portal allowed a clear view of the medial meniscus, femoral condyle and posterior cruciate ligament in all specimens. Workability and instrumentation of the posterolateral compartment was not possible with the needle scope. Direct posterior approaches for the posteromedial compartment access are challenging with the current needle scope options and could only be achieved in over 50%. The postero-lateral compartment was not accessible. An angled lens or a flexible Needle scope would be better suited for developing this technique further

Purpose: We analysed knee prostheses preserving the posterior cruciate ligament (or both cruciates) performed after tibial osteotomy. We determined outcome as a function of any tibial callus deformation created by the tibial osteotomy. Material and methods: This retrospective study included a consecutive series of 56 knee prostheses with preservation of the posterior cruciate ligament (n=43) or both cruciate ligaments (n=13). The patients had undergone prior tibial osteotomy for valgisation (n=47) or varisation (n=9). Seven groups were defined as a function of the preoperative tibial angle prior to TKA. The angle were measured with telegonometry. Minimum follow-up was one year, mean follow-up 4.1±2.8 years. Results: The tibial tuberosity was raised in 15 cases. If there was major valgus or rotation deformation, tibial osteotomy was associated with the prothesis (n=9). At last follow-up, the mean IKSg, IKSf and HSS scores were 81.5, 77.6, and 82.3 respectively. The mean femorotibial angle was 177.4±4.2°. The mean tibial angle was 87.8±3° and the mean femoral angle was 89.8±2°. Preoperative tibial deformation was not influenced by clinical results. In case of preoperative tibial deformation situated between 5° valgus and 5° varus, operation time, blood loss, and femoraotibial axis at last follow-up were not significantly different. To correct for tibial valgus greater than 7°, tibial osteotomy was associated with prosthesis implantation during the same operative time in six out of thirteen cases. For preoperative tibial varus greater than 5°, the femorotibial axis was less well corrected. Discussion: These clinical results were comparable to those reported in other series with preservation or not of the posterior cruciate ligament. Correction of the femorotibial angle was less satisfactory than in certain series, but the deformation and the surgical history were among the most marked in the literature. Preservation of the posterior cruciate ligament (or both cruciates) appears to have increased the technical difficulties for upper tibia exposure and position of the tibia implant. For tibial callus with valgus greater than 7°, the prostheses cannot be expected to provide a solution alone and osteotomy should be associated. For tibial callus with 5° or more varus, the indication for associated tibial osteotomy merits discussion

In an attempt to alleviate symptoms of the disease, patients with knee osteoarthrosis (KOA) frequently alter their gait patterns. Understanding the underlying pathomechanics and identifying KOA phenotypes is essential for improving treatments. We aimed to investigate altered kinematics in patients with KOA to identify subgroups. Sixty-six patients with symptomatic KOA scheduled for total knee arthroplasty and 12 age-matched healthy volunteers with asymptomatic knees were included. We used k-means to separate the patients based on dynamic radiostereometric assessed knee kinematics. Ligament lesions, KOA score, and clinical outcome were assessed by magnetic resonance imaging, radiographs, and patient reported outcome measures, respectively. We identified four clusters that were supported by clinical characteristics. Compared with the healthy group; The flexion group (n=20): revealed increased flexion, greater adduction, and joint narrowing and consisted primarily of patients with medial KOA. The abduction group (n=17): revealed greater abduction, joint narrowing and included primarily patients with lateral KOA. The anterior draw group (n=10): revealed greater anterior draw, external tibial rotation, lateral tibial shift, adduction, and joint narrowing. This group was composed of patients with medial KOA, some degree of anterior cruciate ligament lesion and the greatest KOA score. The external rotation group (n=19): revealed greater external tibial rotation, lateral tibial shift, adduction, and joint narrowing while no anterior draw was observed. This group included primarily patients with medial collateral and posterior cruciate ligament lesions. Patients with KOA can, based on their gait patterns, be classified into four subgroups, which relate to their clinical characteristics. The findings add to our understanding of associations between disease pathology characteristics in the knee and the pathomechanics in patients with KOA. A next step is to investigate if patients in the pathomechanic clusters have different outcomes following total knee arthroplasty

Abstract. Introduction. We present a case series of patients that underwent knee ligament reconstruction with graft reinforcement using FibreTape (Arthrex), a 2mm wide non-biodegradable polyethylene tape. Outcomes and safety of this novel technique are reported. Methods. Data were collected from a prospectively maintained database from 03/2011 to 11/2019. All skeletally mature patients that underwent reinforced knee ligament reconstruction surgery at Basingstoke and North Hampshire Hospital were included. The cohort was interrogated for outcomes including failure, complications, and subjective patient reported outcomes at 6,12 and 24 months postoperatively. Results. 438 patients were eligible. The mean age was 33.4 years and 68% of them were males. This included 171 ACL reconstructions, 96 ACL with anterolatreal ligament reconstructions, 59 bicruciate reconstructions, 30 ACL with posterolateral corner, 49 posterior cruciate ligament with one other ligament and 33 other ligament reconstruction. Allograft was used for 125 patients. 338 cases related to primary reconstruction. The overall complication rate was 5.3%, with a 2.1% re-rupture rate. There were 9 patients with a re-rupture and 5 of them had undergone multiligament reconstruction. We found a statistically significant improvement in all subjective scoring indices post-operatively up to 2 years. There were no complications directly related to the use of ligament reinforcement. Conclusion. Graft reinforcement is a safe option in the management of knee ligament injuries. Encouraging results were observed in patient reported outcomes. Reinforcement is technically reproducible and may represent an answer for graft failure rates, especially in multiligament reconstructions. Further application and evaluation is necessary to confirm its benefit

Instability currently represents the most frequent cause for revision total knee replacement. Instability can be primary from the standpoint of inadequately performed collateral and/or posterior cruciate ligament balancing during primary total knee replacement or it may be secondary to malalignment secondary to loosening which can develop later progressive instability. Revision surgery must take into consideration any component malalignment that may have primarily contributed to instability. Care should be given to assessing collateral ligament integrity. This can be done during physical examination by manual or radiological stress testing to see if the mediolateral stress of the knee comes to a good endpoint. If there is no sense of a palpable endpoint, then the surgeon must assume structural incompetency of the medial or lateral collateral ligament or both. In posterior cruciate ligament retaining knees, anteroposterior instability must be assessed. For instability, most revisions will require a posterior cruciate substituting design or a constrained unlinked condylar design that, although sometimes a posterior cruciate ligament preserving design can be used in situations where the bone-stock is well preserved. However, if the patient displays considerable global instability, a linked, rotating platform constrained total knee replacement design will be required. Recent data has shown that the rotating hinges work quite well in restoring stability to the knee with maintenance of the clinical results over a considerable length of time. During revision surgery, laminar spreaders may be utilised to assess the flexion and extension spaces after the tibial platform is restored. If a symmetric flexion and extension space is achieved, then the collateral ligaments are intact. Depending on the remaining existing bone stock, a posterior stabilised or constrained condylar unlinked prosthesis may be used for implantation. In cases with considerable asymmetry or a large flexion/extension mismatch, then a rotating hinge design should be utilised. Intramedullary stems should be utilised in most cases when bone integrity is suspect and insufficient. Currently, stems should be placed cementless to permit easier future revision. Cementing the stems is only recommended if there is lack of intramedullary isthmic support or there is a hip prosthetic stem that prohibits a stem from engaging the isthmic cortex. However, it should be realised that later revision of the fully cemented revision implant may be quite difficult. Infection should be ruled out by aspiration off of antibiotics prior to any revision operation, especially if loosening of the components represents the cause of instability. The surgeon should attempt to restore collateral ligament balance whenever possible as this yields the best clinical result

We evaluated the long-term outcome of isolated endoscopically-assisted posterior cruciate ligament reconstruction in 26 patients using hamstring tendon autografts after failure of conservative management. At ten years after surgery the mean International Knee Documentation Committee subjective knee score was 87 (. sd. 14) of a possible 100 points. Regular participation in moderate to strenuous activities was possible for only seven patients pre-operatively; this increased to 23 patients post-operatively. The mean Lysholm score improved from 64 (. sd. 15) to 90 (. sd. 14) at ten years (p = 0.001). At ten years endoscopic reconstruction of the posterior cruciate ligament with hamstring tendon autograft is effective in reducing knee symptoms. Of the series, 22 patients underwent radiological assessment for the development of osteoarthritis using the Kellgren-Lawrence grading scale. In four patients, grade 2 changes with loss of joint space was observed and another four patients showed osteophyte formation with moderate joint space narrowing (grade 3). These findings compared favourably with non-operatively managed injuries of the posterior cruciate ligament. This procedure for symptomatic patients with posterior cruciate ligament laxity who have failed conservative management offers good results

We describe a previously unpublished and possibly unrecognised association between injuries to the posterior cruciate ligament and Osgood-Schlatter disease. Over a two-year period the authors have treated thirty patients with isolated or combined injuries to the posterior cruciate ligament, confirmed with MR1 or examination under anaesthetic/arthroscopy. Five of these had previously suffered from Osgood-Schlatter disease as adolescents, leaving them with prominent tibial tuberosities. We feel there may be a significant association between these two conditions and the importance of this association is twofold: – firstly, at the time of injury the prominent tibial tuberosity impacts first and results in increased posterior translation of the tibia rendering the posterior cruciate ligament more prone to injury – secondly, during examination of the injured knee, the prominence of the tibial tubercle may make a posterior sag sign less obvious thus obscuring the diagnosis unless one is diligent. We believe that patients who have previously suffered with Osgood-Schlatter disease are vulnerable to posterior cruciate ligament injury and this should be borne in mind whilst examining them following knee injuries

Aims. Tibial plateau fractures (TPFs) are complex injuries around the knee caused by high- or low-energy trauma. In the present study, we aimed to define the distribution and frequency of TPF lines using a 3D mapping technique and analyze the rationalization of divisions employed by frequently used classifications. Methods. In total, 759 adult patients with 766 affected knees were retrospectively reviewed. The TPF fragments on CT were multiplanar reconstructed, and virtually reduced to match a 3D model of the proximal tibia. 3D heat mapping was subsequently created by graphically superimposing all fracture lines onto a tibia template. Results. The cohort included 405 (53.4%) cases with left knee injuries, 347 (45.7%) cases with right knee injuries, and seven (0.9%) cases with bilateral injuries. On mapping, the hot zones of the fracture lines were mainly concentrated around the anterior cruciate ligament insertion, posterior cruciate ligament insertion, and the inner part of the lateral condyle that extended to the junctional zone between Gerdy’s tubercle and the tibial tubercle. Moreover, the cold zones were scattered in the posteromedial fragment, superior tibiofibular syndesmosis, Gerdy’s tubercle, and tibial tubercle. TPFs with different Orthopaedic Trauma Association/AO Foundation (OTA/AO) subtypes showed peculiar characteristics. Conclusion. TPFs occurred more frequently in the lateral and intermedial column than in the medial column. Fracture lines of tibial plateau occur frequently in the transition zone with marked changes in cortical thickness. According to 3D mapping, the four-column and nine-segment classification had a high degree of matching as compared to the frequently used classifications. Cite this article: Bone Joint Res 2020;9(6):258–267

Introduction We describe an arthroscopic technique of excising a lesion from within the posterior septum of the knee. To our knowledge this has not been described in the literature. Case History A 35-year old male taxi-driver presented with pain in the back of his right knee. Examination did not reveal any abnormality except pain on flexing the knee beyond 90-degrees. MRI showed a multiloculated ganglion in the posterior compartment of the knee. The ganglion was located within the posterior septum and successfully excised arthroscopically. 6-months postoperatively the patient is assyptomatic. Anatomy of the posterior septum The posterior septum is located between the posterior cruciate ligament (PCL) and the posterior capsule dividing the posterior cavity of the knee into seperate posteromedial and posterolateral compartments. It is triangular in shape, formed by the reflections of the synovium from the PCL. The Technique The posterior septum of the knee was approached through the intercondylar notch by the anterior portals. Slow and careful dissection was carried out in the V-shaped space between the anterior and the posterior cruciate ligaments. The synovium of the septum was resected and the space within the septum entered. The ganglion was successfully removed. There was no complication. The relatively central placement of the anterior portals is important to gain access to the posterior septum via the notch. Discussion and conclusion Intra-articular ganglion cysts are uncommon. Reported prevalence ranges from 0.2% to 1.3%. Ganglion cysts arising from the anterior and the posterior cruciate ligaments have been well described. The ganglion cyst within the posterior septum has not been reported. The anatomy of the posterior septum makes it inaccessible to routine arthroscopic examination. It has close proximity to the vascular structures. We approached the posterior septum from the anterior portals through the intercondylar notch. The ganglion was successfully excised

Purpose: Posterior arthroscopy is generally performed by alternating visual control using the optic introduced via one of the anterior portals which is slid into the slit via the contralaeral posterior compartment. These two “crossed” posterior portals provide access to the posterior part of the menisci and to the condyle but remain oblique. Any sagittal partition separating the posterior compartments limits visual and instrument access to the posterior part of the articular cavity. The purpose of this work was to describe a novel back-and-forth technique for posterior arthroscopy which allows posterior access to the central pivot. Material and methods: The conventional posteromedial access was used. The optic was introduced to visualise the posterior cruciate ligament and the posterior partition, and when in contact with it, to push it forward. The optic was then replaced by a round-headed instrument to perforate the partition above the posterior cruciate ligament and penetrate into the lateral compartment. The instrument was pushed against the posterolateral wall determining the point of the corresponding portal. A motorised knife was introduced into the end of the canula then brought into the medial compartment. The posterior partition was resected, creating a single posterior space which could be examined under direct visual control. During an anatomy study, we examined the relationship between the noble elements in the popliteal fossa and the different instruments used during this procedure. Fifteen patients with villonodular synovitis underwent exclusively arthroscopic synovectomy using this approach. Results: We did not have any case of vessel or nerve injury and had no recurrence at mid-term. Postoperatively, patient comfort was much better than after arthrotomy synovectomy. Discussion: This difficult method requires an excellent knowledge of the position of the different anatomic elements in the popliteal fossa close to the posterior part of the articulation. This combined posterior approach facilitates access to the posterior part of the articular cavity of the knee and offers a new approach to the posterior cruciate ligament as well as broader indications for arthroscopic synovectomy with more complete resection. It does not allow access to the submeniscal folds nor to the fibulotibial articulation

Pre-operative planning in revision total knee replacement is important to simplify the surgery for the implant representative, operating room personnel and the surgeon. Revision knee arthroplasty is performed for many different reasons and of variable complexity. Many implant options can be considered including cemented and cementless primary and stemmed revision tibial and femoral components, with posterior cruciate retention or resection, and either with no constraint, varus/valgus constraint, or with rotating hinge bearings. One may also need femoral and tibial spacers, metaphyseal augments, or bulk allograft. It is important to pre-operatively determine which of these implants you may need. If you schedule a revision total knee and ask the implant representative to “bring everything you've got, just in case,” they will have to bring a truck full of instruments and implants. The first step of pre-operative planning is to determine how much implant constraint will be needed. Survivorship of revision total knees with modern varus/valgus constrained or rotating hinge implants are not that unacceptable. Ideally to enhance longevity, the least constraint needed should be used. This requires determination of the status of the ligaments. Varus and valgus stress is applied to the knee in near full extension, mid-flexion, and ninety degrees of flexion. If instability of the knee is noted, then radiographs are reviewed to determine if component malposition or malalignment is the reason for the collateral ligament laxity. If radiographs don't show a reason, then have additional constraint available in case the knee can't be balanced with proper component position and ligament balancing. In cases other than simple revisions, the posterior cruciate ligament is usually inadequate or needs to be resected to balance the knee. Substitution for the posterior cruciate ligament is usually needed for most revisions. The second step of pre-operative planning is to review radiographs to determine the amount and location of any bone loss. Osteolysis induced bone loss is usually worse than seen on plain radiographs. If unsure, a CT scan can be of help. The presence of significant bone loss contraindicates the use of primary components and mandates the need for stemmed implants. Larger defects may warrant having metallic augments or bulk graft present. Most revision knee implants can be conservatively metaphyseal cemented with diaphyseal engaging press-fit stems. The third step of pre-operative planning is to be familiar with what implants are present. Occasionally, one may not need to revise components that are stable and well aligned. Having compatible components available may simplify the surgery. Excellent pre-operative planning will minimise the need to bring in an excessive number of instruments and implants. It will help assure that the patient has a stable revision knee and simplify the surgery for all participants

Purpose. We aimed to investigate whether the anterior superior iliac spine could provide consistent rotational landmark of the tibial component during mobile-bearing medial unicompartmental knee arthroplasty (UKA) using computed tomography (CT). Methods. During sagittal tibial resection, we utilized the ASIS as a rotational landmark. In 47 knees that underwent postoperative CT scans after medial UKA, the tibial component position was assessed by drawing a line tangential to the lateral wall of the tibial component. Rotation of the tibial component was measured using two reference lines: a line perpendicular to the posterior cortical rim of the tibia (angle α) and Akagi's line (angle β). Instant bearing position and posterior cruciate ligament fossa involvement were also evaluated. External rotation of the tibial component relative to each reference line and external rotation of the bearing relative to the lateral wall of the tibial component were considered positive values. Results. The mean angle α and β were 8.0 ± 6.1° (range, −4.0 – 24.3) and 8.7 ± 4.8° (range, 1.9 – 25.2), respectively. The mean instant bearing position was 4.3 ± 28.6° (range, −52.9 – 179.7). One bearing showed complete 180° rotation at 2 weeks postoperatively. Fourteen knees (29.8%) showed posterior cruciate ligament fossa involvement of the tibial resection margin. Conclusions. Due to the wide variation in, and inherent difficulty in identification of, the ASIS during the operation, it is not recommended for guidance of sagittal tibial resection during mobile-bearing medial UKA. Level of Evidence: Level IV

Objective: Many have advocated the importance of correcting posterolateral rotatory instability (PLRI) in injuries causing rupture of the posterior cruciate ligament and PLRI. However, there have been few studies comparing the results of reconstructing the posterior cruciate ligament (PCL) in isolation with PCL reconstruction combined with stabilisation of the posterolateral corner. We set up a retrospective study to directly compare the results of an isolated PCL reconstruction with a combined PCL reconstruction and Larsen tenodesis. Methods: Seventeen consecutive patients with symptoms of instability and chronic rupture of the PCL and PLS were identified from our database. There were 1 1 men and 6 women. Ten patients were injured while playing sport, six in road traffic accidents, and one was a result of a fall. The mean age of the patients at the time of surgery was 31 (range 21–47), and the interval from injury to surgery was a mean of 23 months (months–10 years). The mean follow up was 35 months (14–74 months). All patients had unstable knees, with significant posterolateral rotatory instability. In 12 cases the PCL alone was reconstructed, in 5 cases a combined posterior cruciate ligament and posterolateral corner reconstruction was performed. Prior to surgery all patients underwent a physical examination of both knees. Posterior draw, posterior sag and reverse Lachman tests were used to assess PCL function. Posterolateral rotatory instability was assessed by the dial test. Plain radiographs and either an M [RI or arthroscopy of the affected knee were performed. At follow-up patients underwent examination of both their knees. A subjective assessments of function was made using the Tegner, and Lysholm scoring systems. Results: At a mean follow up of 35 months, both groups had significantly improved compared to their preoperative status, as measured by Lysholm and Tegner scores and posterior draw test (P< 0.01). The group in which only the PCL was reconstructed had significantly lower scores compared to those who had the additional posterolateral corner reconstruction (Tegner P< 0.04, Lysholm P< 0.02). Conclusion: The results of PCL reconstruction were significantly improved when combined with a Larsen tenodesis in patients with severe posterolateral rotatory instability

Objectives. Posterior condylar offset (PCO) and posterior tibial slope (PTS) are critical factors in total knee arthroplasty (TKA). A computational simulation was performed to evaluate the biomechanical effect of PCO and PTS on cruciate retaining TKA. Methods. We generated a subject-specific computational model followed by the development of ± 1 mm, ± 2 mm and ± 3 mm PCO models in the posterior direction, and -3°, 0°, 3° and 6° PTS models with each of the PCO models. Using a validated finite element (FE) model, we investigated the influence of the changes in PCO and PTS on the contact stress in the patellar button and the forces on the posterior cruciate ligament (PCL), patellar tendon and quadriceps muscles under the deep knee-bend loading conditions. Results. Contact stress on the patellar button increased and decreased as PCO translated to the anterior and posterior directions, respectively. In addition, contact stress on the patellar button decreased as PTS increased. These trends were consistent in the FE models with altered PCO. Higher quadriceps muscle and patellar tendon force are required as PCO translated in the anterior direction with an equivalent flexion angle. However, as PTS increased, quadriceps muscle and patellar tendon force reduced in each PCO condition. The forces exerted on the PCL increased as PCO translated to the posterior direction and decreased as PTS increased. Conclusion. The change in PCO alternatively provided positive and negative biomechanical effects, but it led to a reduction in a negative biomechanical effect as PTS increased. Cite this article: K-T. Kang, Y-G. Koh, J. Son, O-R. Kwon, J-S. Lee, S. K. Kwon. A computational simulation study to determine the biomechanical influence of posterior condylar offset and tibial slope in cruciate retaining total knee arthroplasty. Bone Joint Res 2018;7:69–78. DOI: 10.1302/2046-3758.71.BJR-2017-0143.R1

Aim: To accurately identify the meniscofemoral ligaments in cadaveric human specimens, and to determine anatomical variations in the posterior cruciate ligament that may lead to mis-identification of these structures. Methods: A total of 79 fresh frozen knees were examined from 45 cadavers Combined anterior and posterior approaches were used to inspect the vicinity of the posterior cruciate ligament (PCL) for the presence of the anterior and posterior meniscofemoral ligaments. The anterior approach utilised a medial parapatellar incision followed by division of the anterior cruciate ligament, whilst a midline posterior arthrotomy was used for the posterior approach. Further dissection facilitated inspection of the meniscal and femoral attachments of the MFLs, and measurement of their lengths. Videos of MFL and PCL motion during passive flexion of the cadaveric were also performed. Results: In total, 74 (94%) of the 79 specimens contained at least one meniscofemoral ligament. The posterior meniscofemoral ligament (pMFL) was present in 56 (71%) specimens, whilst the anterior meniscofemoral ligament (aMFL) was present in 58 specimens (73%). Both ligaments coexisted in 40 (51%) of knees. In 15 specimens the PCL was seen to have oblique fibres, which attached proximal to the tibial attachment of the main part of the PCL. We termed this “the false pMFL”, as it could be easily mis-identified as the posterior meniscofemoral ligament. Several other anatomical variations were also identified. The mean length of the aMFL was 20.7±3.9mm, whilst that of the pMFL was 23±4.2mm. Although the lengths of the MFLs were relatively constant, there was a wide variation in thickness. Discussion: This study confirms the high incidence of at least one MFL in humans, which suggests a functional role for these structures. The oblique fibres of the PCL can be readily mis-identfied as the pMFL. These caveats should be borne in mind, during both arthroscopic examination and in the interpretation of magnetic resonance imaging (MRI) scans of the knee. Although some variations of the MFLs have been reported on MRI imaging2, there has been no note of the oblique fibres of the PCL reported in the present study. As this variation was present in almost one in five of our specimens, its appearance on MRI scanning requires investigation. The function of the meniscofemoral ligaments is undetermined, although many hypotheses comment on a role in guiding the motion of the lateral meniscus during knee flexion. Other possibilities include a function as a secondary restraint supplementing the posterior cruciate ligament

Objectives. The aim of the current study was to analyse the effects of posterior cruciate ligament (PCL) deficiency on forces of the posterolateral corner structure and on tibiofemoral (TF) and patellofemoral (PF) contact force under dynamic-loading conditions. Methods. A subject-specific knee model was validated using a passive flexion experiment, electromyography data, muscle activation, and previous experimental studies. The simulation was performed on the musculoskeletal models with and without PCL deficiency using a novel force-dependent kinematics method under gait- and squat-loading conditions, followed by probabilistic analysis for material uncertain to be considered. Results. Comparison of predicted passive flexion, posterior drawer kinematics and muscle activation with experimental measurements showed good agreement. Forces of the posterolateral corner structure, and TF and PF contact forces increased with PCL deficiency under gait- and squat-loading conditions. The rate of increase in PF contact force was the greatest during the squat-loading condition. The TF contact forces increased on both medial and lateral compartments during gait-loading conditions. However, during the squat-loading condition, the medial TF contact force tended to increase, while the lateral TF contact forces decreased. The posterolateral corner structure, which showed the greatest increase in force with deficiency of PCL under both gait- and squat-loading conditions, was the popliteus tendon (PT). Conclusion. PCL deficiency is a factor affecting the variability of force on the PT in dynamic-loading conditions, and it could lead to degeneration of the PF joint. Cite this article: K-T. Kang, Y-G. Koh, M. Jung, J-H. Nam, J. Son, Y.H. Lee, S-J. Kim, S-H. Kim. The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions: A computational knee model. Bone Joint Res 2017;6:31–42. DOI: 10.1302/2046-3758.61.BJR-2016-0184.R1

Thirty cruciate ligaments were retrieved from either cadavers or limbs which had been amputated. Each specimen was sectioned and stained to demonstrate the presence of collagen, nerves and vessels. All 30 specimens contained an interconnecting band of collagen fibres between the anterior and posterior cruciate ligaments. Vascular structures were present in all specimens and nerve fibres were identified in 26 (86%). We have called this structure the ‘intercruciate band’. The anterior and posterior cruciate ligaments should no longer be thought of in isolation, but together as a ‘cruciate complex’

Our aims were to map the tibial footprint of the posterior cruciate ligament (PCL) using MRI in patients undergoing PCL-preserving total knee replacement, and to document the disruption of this footprint as a result of the tibial cut. In 26 consecutive patients plain radiography and MRI of the knee were performed pre-operatively, and plain radiography post-operatively. The lower margin of the PCL footprint was located a mean of 1 mm (−10 to 8) above the upper aspect of the fibular head. The mean surface area was 83 mm. 2. (49 to 142). One-third of patients (8 of 22) had tibial cuts made below the lowest aspect of the PCL footprint (complete removal) and one-third (9 of 22) had cuts extending into the footprint (partial removal). The remaining patients (5 of 22) had footprints unaffected by the cuts, keeping them intact. Our study highlights the wide variation in the location of the tibial PCL footprint when referenced against the fibula. Proximal tibial cuts using conventional jigs resulted in the removal of a significant portion, if not all of the PCL footprint in most of the patients in our study. Our findings suggest that when performing PCL-retaining total knee replacement the tibial attachment of the PCL is often removed

Purpose of the study: Kinetic studies of total knee arthroplasty (TKA) in vivo have provided divergent data but have agreed on one point: knee kinetics is abnormal after TKA. Restitution of a normal kinetics is thus the goal to reach to improve functional outcome after TKA. The Journey. ®. TKA is specifically designed to induce automatic medial rotation of the tibia during flexion. This would align the extensor system during flexion and would reduce mediolateral shear forces applied to the patellofemoral joint. Fluoroscopic dynamic studies have been conducted in vivo to confirm the reality of the femorotibal kinematics but to date there has been no study of the patellofemoral kinematics. Magnetic resonance imaging (MRI) is the gold standard for exploring the knee. The important artefacts caused by metal implants made of chromium-cobalt alloys make it difficult or impossible to interpret the images in patients with TKA. Oxinium. ®. implants are weakly ferromagnetic, allowing the development of a specific MRI sequence which can be used to explore a TKA. Material and methods: We used this technique in vivo for a 3D exploration of the patellofemoral kinematics of six Jouney. ®. TKA in comparison with five Genesis II. ®. TKA with preservation of the posterior cruciate ligament and with 13 normal knees. We analysed: patellofemoral surface area of contact, patellar translation and shift during weight-bearing flexion. Results: The results showed that the patellofemoral kinematics of the Journey. ®. TKA are close to that observed in normal knees and that the patellofemoral pressures of the posterior cruciate ligament TKA are significantly higher than with the Journey. ®. TKA. Discussion: These findings confirm our initial hypothesis and allow hop for better functional outcome and reduced wear of the patellar implant with the Journey. ®. TKA

Introduction. Restoration of knee function after total knee arthroplasty (TKA) often entails a balance between normal kinematics and normal knee stability, especially in performing demanding physical activities. The ultra-congruent (UC) knee design prioritizes stability over kinematics through close conformity between the femoral component and the tibial insert in extension. This configuration is intended to provide AP stability in the absence of the posterior cruciate ligament during activities that would otherwise cause anterior femoral subluxation. In this study we examine the kinematics of an ultra-congruent knee design in comparison with the intact knee and with conventional articulations used in PCL-retaining (CR) and PCL-substituting (PS) TKR designs. Materials and Methods. The 3D tibio-femoral kinematics of 6 fresh frozen cadaveric human knees were tested during loaded simulation of squatting in a computer-controlled knee testing rig. Muscle forces were simulated by loading rectus femoris and vastus intermedius (150N), vastus lateralis (100N), vastus medialis (75N), and the hamstring muscles (60N) (total: 385N). Testing was performed on the intact knee, and after implanting a standard design of total knee prosthesis with the posterior cruciate ligament intact (CR-TKA), resected (PCL-substituting insert; PS-TKA), and a UC insert (UC-TKA group). The 3D positions of the tibia and femur were tracked with a high resolution 12 camera motion analysis system (Motion Analysis Inc.) and used to position 3D CT reconstructions of each bone. The translation and rotation of the femur with respect to the tibia were calculated by projecting the femoral transcondylar axis onto a plane normal to the longitudinal anatomical axis of the tibia coincident with the transverse axis of the tibial plateau. Results. In full extension, the femur was displaced posteriorly by 14.2 ±7.0 mm compared to the intact knee (p<0.01). There was minimal posterior translation (±3mm) of the medial condyle with all 3 inserts designs, and minimal (0–3mm) translation of the lateral condyle from 0–90 degrees with both the UC and PS inserts. From 0–30 degrees flexion, the femoral component translated anteriorly by approx. 5mm without axial rotation. Beyond 30 degrees, the tibia rotated internally by a total of 11 degrees (30–120degs). This was associated with approx. 5mm of rollback of the lateral condyle and 5mm of anterior translation of the medial condyle. There was significant difference in tibial rotation between the UC-TKA group and the intact knee group (p<0.01 in UC-TKA group at 15, 30, 45, and 60°). The rotation patterns of the three designs of TKA were similar during flexion from 0–120 degrees. This was markedly different than the intact knees. Conclusions. The UC TKA demonstrated minimal AP translation with flexion averaging approx. 6mm of posterior rollback laterally, and 3mm of anterior translation medially from 0–120 degrees. This differential translation was associated with 9degrees of internal rotation pattern, similar to that of the PS insert. The clinical success of the UC design and its popularity with patients as an alternative to the PS-TKA suggests that AP stability in extension, and not posterior rollback in flexion, is a critical element in patient satisfaction after TKR