Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has largely been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e. whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA.

We analysed the shape of 114 arthritic knees at the time of primary TKA using the pre- operative CT scans. The aspect ratio and trapezoidicity ratio were quantified, and the post- operative prosthetic overhang was calculated. We compared the morphological characteristics with those of 12 TKA models.

There was significant variation in both the aspect ratio and trapezoidicity ratio between individuals. Femoral trapezoidicity was mostly due to an inward curve of the medial cortex. Overhang was correlated with the aspect ratio (with a greater chance of overhang in narrow femurs), trapezoidicity ratio (with a greater chance in trapezoidal femurs), and the tibio- femoral angle (with a greater chance in valgus knees).

This study shows that rectangular/trapezoidal variability of the distal femur cannot be ignored. Most of the femoral components which were tested appeared to be excessively rectangular when compared with the bony contours of the distal femur. These findings suggest that the design of TKA should be more concerned with matching the trapezoidal/ rectangular shape of the native femur.

Introduction

Numerous types of graft can be used for revision of anterior cruciate ligament (ACL) reconstruction. The goal of our studies was to analyze mid term outcomes of revision of anterior cruciate ligament reconstructions conducted by means of ipsilateral bone -patellar tendon -bone (B-PT-B) transplant.

Introduction

There is a challenge to detect partial tear of the ACL, the number of bundle injured and the proportion of fibers torn. The MRI was shown efficient to individualize the two anteromedial (AM) and posterolateral (PL) bundles of the ACL. The purpose of this study was to assess the ability of the MRI to detect partial tears of the ACL on axial views to display the AM and PL bundles.

Mobile-bearing total knee arthroplasty was developed to provide low contact stress and reasonably unrestricted joint motion. We studied the results of a cementless, posterior cruciate ligament (PCL)-retaining total knee arthroplasty (TKA), with a mobile-bearing insert in rotation and anterior-posterior (AP) translation (Innex^® Anterior-Posterior Glide, Zimmer).

Kinematic analyses were performed on a series of 51 primary TKA. The patients’ mean age was 71±8 years at operation. Patients were studied at 23 months average follow-up with weight-bearing radiographs at full-extension, 30° flexion and maximum flexion (“lunge” position). Three dimensional position and orientation of the mobile-bearing relative to the femoral and the tibial component during flexion were determined using model-based shapematching techniques.

The average weight-bearing range of implant motion was 110°±14°. In flexion, the mobile-bearing was internally rotated 3°±3° with respect to the femoral component (p< 0.0001) and the tibial tray was internally rotated 5°±7° with respect to the mobile-bearing (p< 0.0001). On average, the mobile-bearing did not translate relative to the tibial base plate from full extension to 45° flexion [0±2 mm (range −5 mm to 6 mm)]. However, the mobilebearing did translate anteriorly 1±2 mm (range −2 mm to 9 mm, p< 0.0001) between 45° flexion and maximal flexion.

We conclude that the mobile-bearing insert showed a progressive increase in internal rotation during flexion. Most of this rotational mobility occurred between the mobile insert and the tibial base plate. With flexion, AP translation did occur between the femoral component and mobile-bearing, and between the mobile-bearing and tibial base plate, but mobile-bearing translation was unpredictable with this unconstrained design.

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.

Purpose of the study: Revision ligamentoplasty can improve function and laxity control but with a less satisfactory result than obtained after primary reconstruction. The purpose of this study was to report management practices and results of revision ACL reconstructions and to assess the course of meniscocartilage damage and determine causes of failures.

Material and method: This was a consecutive series of ten patients, mean age 30 years (range 17–48) who underwent arthroscopic reconstruction. The review was retrospective. Criteria for failure were redevelopment of instability and/or pain, objective laxity, and a KT-100 differential greater than 5 mm. The IKDC protocol was used for the clinical and radiographic assessment. Goniometry, arthroscan and MRI were also performed. The position of the tunnels was analysed according to the Aglietti criteria. The type of surgery, transplant used and status of the menisci and cartilage were analysed.

Results: Mean follow-up of the second revision was 38 months. At last follow-up, seven patients had a global IKDC score of A or B. Two patients had resumed regular sports activities at the same level as before the first tear, four at a lower level. Four had interrupted their sports activities. At the second revision, two patients exhibited medial femorotibial narrowing measured at less than 50%, three had a remodelled medial femorotibial compartment and one a remodelled lateral compartment. All had a partial homolateral meniscectomy and seven had cartilage injuries (3 ICRS III and 1 ICRS IV). At the successive interventions, the number of meniscal lesions, meniscetomies, and cartilage lesions increased (p=0.016, 00098 and 0.0197 respectively). ICRS grade II and IV cartilage lesions were associated with an overall C or D IKCD (p=0.0472). The cartilage lesions were more frequent in knees with meniscal lesions and meniscectomies. The causes of failure of the primary ligamentoplasty and of the first revision (six and seven patients respectively) were poor position of the tunnels (respectively 4 and 1 patients).

Discussion: In 70% of the patients outcome after repeated revision was good or excellent, although the quality declined with increasing number of revisions, in relation to the development of meniscal and cartilaginous lesions. These latter were more frequent and more severe, related to recurrent laxity. Failures were mainly due to recurrent trauma followed by technical errors.

Purpose of the study: Anteversion of the cup during total hip arthroplasty (THA) is crucial for preventing the risk of dislocation. Interest has recently focused on an anatomic element often observed in the operative field during hip surgery: the transverse acetabular ligament (TAL). The TAL has become a landmark both for conventional procedures (Beverland) and for computed-assisted surgery. The purpose of this original research was to study the anteversion of the TAL in relation to the anterior pelvic plane in order to determine whether it could be a valid landmark for positioning the cup using the Lewinnek criteria (35±20° anteversion according to the Murray definition).

Material and methods: Eight laboratory cadavers (three male, five female, mean age 82±3.3 years) were dissected; the pelvis was removed. Fifteen fresh healthy hips (free of trauma or degenerative disease) were also used for the study. The orientation of the peri-acetabular structures was measured with the probe of the BrainLab^® navigation system and the Motion Analysis^® system (Santa Rosa. CA) at the laboratory of biomechanics and biomechanical shocks (INRETS, Bron). The Lewinnek reference plane (anterior pelvic plane) was defined from the anterosuperior iliac spines and the pubic tubercles.

Results: The anatomic version of the TAL varied from −8 to +13.3 (mean 1.9); the anatomic version of the horns of the semilunate surface from −12.2 to +14 (mean 3); for the labrum the figures were +17.4 to +41.8 (mean 26.63). Anteversion of the TAL and the horns were well correlated (r=0.8) significantly (p=0.001).

Discussion: There is no other study concerning the anatomic orientation of the TAL, the horns and the labrum. Archbold was the first to consider the TAL (1000 cases, posterolateral access, 28 mm head) as a reliable constant landmark for positioning the cup (0.6% dislocation). In our study, the anatomic version of the TAL was found outside the safety zone of Lewinnek. This is a supplementary argument for questioning the reliability of the Lewinnek criteria based solely on nine cases of dislocation and criticised by several authors (non-specific for each patient).

Conclusion: Anteversion of the labrum is situated within this safety zone. The TAL does not position the cup in the Lewinnek safety zone, which remains controversial.

Purpose of the study: From a biomechanical view, the medial force stabilising the patella is assured for 50 to 60% by the medial patellofemoral ligament (MPFL). The purpose of this cadaver study was to present a precise description of the anatomic features of the MPFL concerning its femoral insertion, its relations with the oblique vastus medialis (OVM) and its relation with the medial collateral ligament (MCL) in order to optimise surgical reconstruction.

Material and methods: This cadaver study was performed on 23 knees from fresh cadavers. All measures were made knee flexed 30° by the same operator. Insertions of the OVM on the MPFL, when present, were identified. The length of the zone of reflexion was recorded. For these measurements, a orthonormal landmark centred on the femoral insertion of the MPFL was established. This landmark was used to position the medial epicondyle and the adductor tubercle for each knee.

Results: The MPFL was found in all 23 knees (100%); the length of the MPFL was 57.7±5.8 mm; its femoral insertion measured 12.2±2.6 mm (8–136); its patellar insertion measured 24.4±4.8 mm. A junction between the OVM and the MPFL was found for all 23 knees (100%). This zone appeared to be a veritable reflexion zone with the OVM fibres arching over the MPFL fibres for a length of 25.7±6 mm.

Discussion: Our study confirms the constant presence of the MPFL, observed in 100% of the knees studied. During the reconstruction of the MPFL, the key point is the position of the femoral insertion of the ligament, in order to restore the native femoral insertion of the MPFL surgically and thus attempt to recreate perfect isometry of the graft. The graft must be positions 10 mm posteriorly to the medial epicondyle and 10 mm distally to the adductor tubercle. In our cadaver the MPFL, the main medial stabilising force of the patella was a constant finding, always located in the second thickness of the medial plane of the knee.

Conclusion: We detailed the native femoral insertion of the MPFL and described its relations with the medial femoral epicondyle and the adductor tubercle using an orthonormal landmark. Long-term function of the graft depends on proper positioning.

Introduction: Autologous chondrocyte implantation was introduced in 1994 by Brittberg and Peterson for the treatment of large full-thickness focal chondral defects. The purpose of the present study was to evaluate the mid-term results of this technique in a group of patients with post-traumatic chondral defects of the knee.

Materials and Methods: Fifteen patients underwent autologous chondrocyte implantation between 2001 and 2006 and were prospectively assessed preoperatively, at 3, 6, 9, 12 months, 3.5 years and last follow-up with use of standard rating scales (IKDC subjective score, pain Visual Analogic Scale (VAS), Brittberg and Peterson’s score). The inclusion’s criteria were: pain VAS more than 40/100, age between 18 and 50 years, focal chondral defect in weight bearing area grade 3 or 4 and informed and signed consent. Patients with varus or valgus deformities with malalignement more than 5 degrees, knee instabilities and signs of arthritis on radiographs were excluded. The same experienced surgeon performed all the procedures.

Results: Fourteen patients were reviewed at the latest follow-up. The mean age of the patients at the time of autologous chondrocyte transplantation was 37.7 years (range, 30 to 45). The mean duration of symptoms was 2.9 years (0.5 to 7). Nine patients (83%) had previous operations on the index knee. The defect was located on the medial femoral condyle in 11 patients and on the lateral femoral condyle in 3. The mean lesion size was 1.80 cm² (range, 1.5 to 3.5 cm²) after débridement. After a mean duration of follow-up of 6 years (3.3–7.8), 84% of the patients had improvement on a patient self-assessment questionnaire. The IKDC subjective score and Brittberg-Peterson’s score were all improved. The mean IKDC subjective score increased from 40 (27.6–65.5) preoperatively to 60.2 (35.6–89.6) at the latest evaluation. The mean pain VAS decreased from 66.3 (44–89) to 23.2 (0–77). The Brittberg and Peterson’s score decreased from 54.4 (11.8–98.2) to 32.9 (0–83.9). Two patients (16.7%) felt no improvement by the chondrocyte transplantation at the last follow-up. Two complications occurred: graft periosteum hypertrophy treated by débridement and a pulmonary embolus.

Discussion: Our results are similar than those reported in the literature. These outcomes are encouraging and need further follow-up to confirm the long-term efficacy of autologous chondrocyte implantation.

The purpose of this study was to compare 2 different strategies of management for ACL rupture in skeletally immature patient.

In group 1, patients were treated in a children hospital by ACL reconstruction with open physis. In group 2, patients were treated in an adult hospital by delayed reconstruction at skeletal maturity assessed radiologically.

Fifty six consecutive patients were included in this retrospective study. Mean time from injury to surgery in group 1 and 2, was 13.5 and 30 months, respectively.

In the overall series, a long time from injury to surgery increased the number of medial meniscal tear (p< 0.0001), but had no influence in the number of lateral meniscal tear (p=0.696). Patients in group 2 exhibited a higher rate of medial meniscal tears (41%) compared to group 1 (16%) (p=0.01). Both groups had the same rate of lateral meniscal tears (p=1). Despite there was no difference between the 2 studied groups in type and location of menisci lesion, patients in group 2 underwent more partial menisectomy (63%) than patients in group 1 (16%) (p=0,014).

One temporary tibial valgus deformity was reported and spontaneously resolved. No definitive growth disturbance was noticed. At 27 months mean follow-up, patients in group 1 expressed better subjective IKDC than in group 2. Objective IKDC and radiological results were similar in both groups.

Early ACL reconstruction in skeletally immature patient, especially if the patient is more than one year to be skeletally mature, has to be promoted despite of growth disturbance risk. This strategy will decrease medial meniscus lesions and partial meniscectomies which occurred more frequently when ACL reconstruction had been delayed until skeletal maturity.

Introduction: The anterior cruciate ligament (ACL) can be anatomically divided into two bundles: the anteromedial (AM) and the posterolateral (PL). These two bundles have unique contributions to load transfer across the knee joint.

Material and Methods: We retrospectively reviewed the clinical results of a consecutive series of 25 patients who underwent partial ACL reconstruction. In 22 cases AM bundle reconstruction was performed, and in 3 patients isolated PL bundle reconstruction was performed.

The 25 patients included 7 women and 18 men with an average age of 29.2 years at the time of surgery.

Preoperative evaluation was conducted using manual Lachman test, pivot-shift tests, KT-1000, magnetic resonance imaging and passive stress radiographs of both knees. In all cases preoperative clinical evaluation was graded C as per the IKDC scoring system. The preoperative side-to-side anterior laxity measured by means of the KT-1000 was 5.8 mm in case of AM bundle rupture and 4.3 mm in case of PL bundle rupture.

All the patients underwent single-bundle reconstruction of the ACL under arthroscopic assistance (one single incision technique).

In case of AM bundle repair, the type of graft used was all autologous and included bone-patellar tendon-bone in 14 cases, 4-strand hamstring tendons in 5 cases and 2-strand hamstring tendons in 3 cases.

In case of PL bundle repair, 2-strand hamstring tendons transplant was used in the 3 cases.

Results: In all cases, postoperative clinical evaluation was graded A as per the IKDC knee examination scoring system. No abnormal sagittal laxity was found with the Lachman manual test. Postoperative IKDC knee subjective evaluation score averaged 81.3 % [58–95] at an average of 9 months follow-up.

Postoperative side-to-side anterior laxity measured with KT-1000 averaged 0.46 mm in case of AM bundle rupture and 0.5 mm in case of PL bundle rupture.

Postoperatively, all the patients had full extension of the knee. The flexion was the same as contra lateral knee in 92 % of the cases. We had no postoperative complication.

Discussion: Diagnosis of partial ACL rupture is often difficult. If the AM bundle is torn, the Lachman manual test is soft and the pivot-shift test is more often equal or glide. If the Lachman manual test is intermediary between firm and soft and the pivot-shift test is clunk, PL rupture has probably occurred.

The size of the graft was smaller than in one bundle procedures and was matched with the size of the bundle reconstucted. Peroperative technical difficulties were to preserve the healthy bundle and to drill the femoral tunnel in case of posterolateral bundle reconstruction.

Conclusion: This study showed consistent postoperative results. If partial rupture of the ACL can be diagnosed, isolated AM or PL bundle reconstruction should be considered.

Purpose of the study: The correct position of the femoral and tibial tunnes for anterior cruciate ligament (ACL) reconstruction is a determining factor for favorable outcome. We used a novel computer-assisted system which enables intraoperative localization of the tunnel centers on the lateral view of the knee before drilling. This technique uses fluoroscopy combined with a passive system for computer-assisted image acquisition and processing to provide the surgeon with the desired positions. We report the anatomic and clinical results observed in a prospective series comparing this technique with the classical technique of independent blind tunnels.

Material and methods: Thirty-seven patients underwent computer-assisted surgery and 36 classical surgery without computer assistance performed by a senior surgeon. Mean patient age was 27 years in both groups. The patients were reviewed at mean 2.2 years (range 1–4.5 years). Data recorded included the KT-1000 laxity, radiographic drawer and the IKDC score (1999).

Results: Mean time from ACL tear to reconstruction was 30 months in both groups. Computer assistance increased operative time 9.3 minutes (range 4–13). The IKDC score was 67.9% A, 29.7% B, and 2.7% C in computer-assistance surgery patients and 60% A, 37.1% B and 2.9% B for classical surgery patients. The mean IKDC function score was 89.7/100 for the computer-assisted patients and 89.5/100 for the others. Mean manual maximal laxity (KT-1000) was 7 mm before surgery and less than 2 mm at last follow-up. Differential laxity was less than 2 mm in all patients who underwent computer-assisted surgery and in 97.7% of the others. The mean differential laxity for the medial compartment as measured on the postoperative stress films was 2.4 mm (range 0–12 mm) for computer-assisted surgery patients and 3 mm (range 0–10 mm) for the others. In the computer-assised surgery patients, the femoral tunnels were centered on a smaller area. There was not significant difference in the IKDC score, the KT-1000 findings and the stress x-rays between the two techniques.

Conclusion: The results of these two techniques in this report are similar to data reported in the literature. Computer-assistance enables more accurate and reproducible tunnel positioning with no significant clinical impact.

Purpose: Revision total knee arthroplasty using gliding prostheses raises numerous technical difficulties. One of the main objectives is to restore the level of the joint line to correspond the space in flexion and extension and maintain patellar height. This is difficult in the event of bone loss which modifies usual landmarks. The basic problem is to find a correspondence between the preoperative planning and the intraoperative execution. We propose a simple method to achieve this objective.

Material and methods: The height of the joint line is determined indirectly from measurements of the lengths of each of the lower limb segments and the mechanical axes. Restoration of the respective lengths of the femur and tibia enables obtaining the original height of the joint line. This produces true bone balance for revision procedures where the ligament balance is limited. The surgical technique consists in drilling two holes with a 4.5 mm drill in the anterior cortical of the femur and tibia at a known distance from the joint line (8–10 cm) before removal of the implants. Once the trial pieces are in place, the distance to the joint line of each bone segment is check to adapt the prostheses. Measurement of the joint line is dependent on the tibia and the femur. It is evaluated by comparison of the lengths of the limb segments (femur and tibia) before and after operation. We measured a continuous series of 26 patients Pre and postoperative goniometry was used with the length of the contralateral fibula serving as a guide to avoid magnification effects.

Results: The mean difference in length before and after surgery was 1.15 mm for the tibia and 2.01 mm for the femur.

Discussion: It is always possible to restore femur length. The trend is globally to lengthening. This is usual and attributed to ligament balance before the operation. Restoration of the joint line is not always possible or desirable. The hole landmark method is useful and reliable to localise and restore the joint line desired by the surgeon. It is the key to restored space symmetry in flexion and extension while preserving the length of each of the bone segments to achieve bone balance.