Aims

The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Background

The goal of patellofemoral arthroplasty (PFA) is to replace damaged cartilage, and to correct underlying deformities, to reduce pain and prevent maltracking. We aimed to determine how PFA modifies patellar height, tilt, and tibial tuberosity to trochlear groove (TT-TG) distance. The hypothesis was that PFA would correct trochlear dysplasia or extensor mechanism malalignment.

The study aimed to compare trochlear profiles in recent total knee arthroplasty (TKA) models and to determine whether they feature improvements compared to their predecessors. The hypothesis was that recent TKA models have more anatomic trochlear compartments and would display no signs of trochlear dysplasia.

The authors analyzed the geometry of the 6 following TKA models using engineering software: PFC and Attune (DePuy), NexGen and Persona (Zimmer), Noetos and KneeTec (Tornier). The mediolateral trochlear profiles were plotted at various flexion angles (0°, 15°, 30° and 45°) to deduce the sulcus angle.

Analysis of sulcus angles reveals general convergence of recent designs towards anatomic values. At 0° of flexion, sulcus angles of recent implant models were between 156.0–157.4°, while those of previous generation models between 154.5–165.5°. At 30° of flexion, sulcus angles of recent models also lie within 145.7–148.6°, but those of previous models are between 149.5–152.0°. All three manufacturers deepened their trochlear profile at 30° of flexion in recent models compared to earlier designs. Sulcus angles converge towards anatomic values but still exceed radiologic signs of dysplasia by 2–5°.

Recent TKA designs have more anatomic trochlear geometries than earlier TKA models by the same manufacturers, but trochlear compartments still exceed radiologic signs of trochlear dysplasia by 2° to 5°. The hypothesis that recent TKA models display no signs of trochlear dysplasia is therefore refuted. Surgeons should be aware of design limitations to optimize choice of implant and extensor mechanisms alignment. Level of evidence: IV geometric implant analysis.

Introduction

Patellar stability is an important component for a correct kinematic behaviour of the knee that depends on several factors such as joint geometry, muscles strength and soft tissues actions. Patellofemoral (PF) maltracking can results in many joint disorders which can cause pain and mobility alterations. The medial patellofemoral ligament (MPFL) is an important stabilizing structure for the patellofemoral joint. The aim of this study was to analyze patellofemoral kinematics with particular attention to the contribution of MPFL on patella stability.

Purpose of the study: Grafting the anterior cruciate ligament with a bone-tendon-bone free transplant injures the harvesting site, causing sensorial disorders by injuring the infrapatellar nerve in 70% of the cases. Mini-invasive techniques can limit these complications. The purpose of this work was to analyse the feasibility of a mini-invasive technique using a single incision.

Material and methods: A prospective comparative study was conducted in our unit to compare a group of “classical” harvesting via an anteromedial incision and a “mini-invasive” technique using a incision centred on the patella with the graft being harvested with a specially designed harvesting instrument. Each group was composed of 20 patients. The patients were reviewed six to eight months postoperatively. Clinical assessment (IKDC, Lillois score, analysis of sensorial impairment) was associated with the radiographic and ultrasound analysis. Radiographic laxity was assessed on the stress views at 15 kg. The ultrasound study analysed the patellar tendon and the peritendon. Significance for statistical tests was set at 0.05 with correlation coefficients (R) determined with a covariance matrix ½ Log([1 + R]/[1−R]).

Results: The grafts harvested by the classical method presented good characteristics in all cases whereas this was true for only 45% of the mini-invasive grafts. Anterior pain was noted in 22% of patients in the classical group and in 33 of the mini-invasive group. There was no correlation between anterior knee pain and knee walking or thickness of the peritendon. A correlation was found between knee walking and asymmetry of the patellar tendon thickness in the mini-invasive group. The subjective IKDC score was the same in the two groups and the IKDC objective score was not significantly different (94% (A or B) in the classic group and 81% (A or B) in the mini-invasive group.

Conclusion: This mini-invasive technique with a single incision respects the infrapatellar branches of the medial saphenous nerve in 95% of the cases. But the quality of the graft is less satisfactory than with the classical harvesting technique. A correlation was found between the form of the anterior tibial tubercle which could be used to better define the ideal indication for this technique which remains a difficult procedure.

Purpose of the study: The form of the anterior tibial tuberosity (ATT) has not been described in anatomy studies. Insertion of the patellar tendon can, by its form, modify the lever arm of the extensor system and induce pathological conditions having an impact on the form of the apex or tip of the patella. The purpose of this work was to analyse the types of tibial tuberosities observed on the radiographs of 50 patients.

Material and method: Fifty patients were included in this prospective study. The form of the ATT was defined by two angles. These angles were measured on the strictly lateral x-ray. The ATT-shaft angle (ATT-d) was defined by the intersection between the anatomic axis of the tibial diaphysis and the anterior cortical of the ATT which corresponds to the insertion of the patellar tendon. The ATT-metaphysis angle (ATT-M) was defined by the angle between the tangents of the anterior metaphyseal cortical and the anterior cortical of the ATT. The height of the patella was also measured as described by Caton and Deschamps. The form of the patella on the lateral was described according to the Grelsamer criteria, and its form on the 30° axial view according to the Wiberg classification. The presence of trochelar dyplasia was determined using the Dejour method. The statistical analysis accepted p < 0.05 as significant. The coefficients of correlation R were calculated with a ½ log covariance matrix [1+R]/[1−R].

Results: The form of the ATT was given by the minimal value between the ATT-D and the ATT-M. This angle measurement revealed major variation. Three types of ATT were defined: type I 0≤ATT-M≤15 and ATT-D≤5, type II 15 < ATT-M < 20 and 5 < ATT-D < 10 and type III 20≤ATT-M 10≤ATT-D. There was an obvious correlation with the form of the patellar apex. The type III form of the patella was always associated with a type I ATT; there was a significantly association between patella type I and ATT type II and patella type III and ATT type I. There was no correlation with the height of the patella or with the form of the trochlea or the patella.

Conclusion: The form of the ATT is quantifiable and becomes a parameter to consider in the analysis of patellofemoral osteoarthritis.

Purpose of the study: The purpose of this work was to search for a relationship between the size of the femoral cam, the presence of cup retroversion, and the presence of labral or chondral lesions on the arthroscan in patients with an asymptomatic femoroacetabular impingement.

Material and method: Fifty arthroscans were obtained to explore impingements. The patients complained of groin or trochanteric pain limiting their physical activities. Generally signs of an anterosuperior impingement were demonstrated with flexion-adduction-internal rotation. The localization, dimensions and depth of the cartilage lesions were measured on the arthroscan. The sagittal slice was used to describe the acetabular chondral lesions anteriorly to posteriorly in clockwise manner. Presence of an associated labral lesion was noted. A second operator measured the hip joint anomalies causing the impingement: Notzli’s alpha angle was measured to search for a cam effect and the femoral offset was noted.

Results: The presence of a femoral cam or a decreased femoral offset were found in all cases. Mean alpha angle was 65°; mean offset was 0.09. Acetabular retroversion was identified in 24 patients (48%). Chondral lesions were a constant finding and were superficial (type 1& 2) in 32 patients (64%) and deep (type 3& 4) in 18 patients (36%). Labral lesions were found in 28 patients (56%). The depth of the chondral lesions, like the presence of a labral lesion, were correlated significantly with increased alpha angle and patient age. There was conversely no correlation with the presence of acetabular retroversion.

Discussion: This study confirmed the close relationship between femoroacetabular impingement by a cam effect and the severity of labral lesions and acetabular cartilage lesions. These lesions can favour degeneration, explaining the early centred or posterinferior damage observed in young patients with satisfactory acetabular cover.

Introduction: Clinical presentation of mucoid degeneration of the anterior cruciate ligament (MDACL) associated knee flexion limitation and posterior knee pain. Treatment needs an anterior cruciate ligament resection, with some questions about harmlessness of this procedure. Our hypothesis was that arthroscopic MDACL treatment is an effective procedure for pain and mobility but creates some anterior knee laxity.

Materials and Methods: This is a retrospective cohort study including 29 cases of MDACL (19 men, 8 women). Mean age was 49 years (range 28 to 68). Mean follow-up was 6 years. Diagnosis was done associated clinical and MRI criteria and was confirmed using Mc Intyre’s arthroscopic criteria. A histological analysis was done in 18 cases. Postoperative functional evaluation was done using IKDC and KOOS score. Knee laxity was appreciated using clinical evaluation and radiological evaluation by TELOS measurement. Statistical analysis was done using Student t-test (level of significance: p< 0.005).

Results: Preoperatively, posterior knee pain was present in 23 knees, and knee flexion limitation in 14 cases. In 10 cases, MDACL was initially misdiagnosed with an inappropriate primary operative treatment. None of theses patients have an anterior knee laxity. Partial anterior cruciate ligament resection was done in 12 cases and complete resection in 17 cases. Meniscectomy was associated in 11 cases. In cases with histological study, diagnosis was always confirmed. After resection knee was painless in 27 cases, and knee flexion increase was 21.52°. A positive Lachman’s test was noted after surgery in all cases, (with a positive Jerk test in 8 cases). Postoperative radiological laxity was greater on the operated side (operated knee vs normal knee: 12.64 /4.33 mm, p< 0.001) Two young patients have need secondary an ACL reconstruction. Two old patients have needed secondary knee prosthesis after 2 and 3 years. Mean postoperative IKDC score was 71.19 (range 42.53 to 91.95) and mean postoperative KOOS score was 78.16 (range 26.40 to 99). Statistical analysis have showed better results for patient older than 50 years, after partial resection and for patient without meniscal associated lesions.

Discussion: Mucoid degeneration of the anterior cruciate ligament should not be confused with anterior cruciate ligament ganglia. Accurate diagnosis could be done using clinical, MRI and arthroscopic diagnosis criteria’s. Arthroscopic treatment of MDACL is an efficient procedure for knee pain and to restore a better knee flexion. However, this procedure created a signifiant anterior knee laxity and could lead in some cases to knee instability especially in young patients.

Objective patellar instability has been correlated with dysplasia of the femoral trochlea. This in vitro study tested the hypothesis that trochleoplasty would increase patellar stability and normalise the kinematics of a knee with a dysplastic trochlea. Six fresh-frozen knees were loaded via the heads of the quadriceps. The patella was displaced 10 mm laterally and the displacing force was measured from 0° to 90° of flexion. Patellar tracking was measured from 0° to 130° of knee flexion using magnetic sensors. These tests were repeated after raising the central anterior trochlea to simulate dysplasia, and repeated again after performing a trochleoplasty on each specimen. The simulated dysplasia significantly reduced stability from that of the normal knee (p < 0.001). Trochleoplasty significantly increased the stability (p < 0.001), so that it did not then differ significantly from the normal knee (p = 0.244). There were small but statistically significant changes in patellar tracking (p< 0.001).

This study has provided objective biomechanical data to support the use of trochleoplasty in the treatment of patellar instability associated with femoral trochlear dysplasia.

Purpose: There is some controversy over the most appropriate management of knee dislocation. Following the 1995 SOFCOT symposium, the most promising results appeared to be obtained with emergency treatment using a synthetic reinforcement. The purpose of this prospective work was to validate this conclusion.

Material and methods: Between November 1994 and October 1998, 17 patients admitted for emergency care of a knee dislocation were included in this prospective study. Ten were men, mean age was 29 years (17–48). A complete work-up was acquired: plain radiographs with stress views, MRI in 14 patients. The central pivot was torn in all cases. Tears involved the lateral ligaments in eleven cases, the medial ligaments in six and the patellar tendon in one. There were no vessel lesions. One patient had popliteal sciatic nerve paralysis. Emergency surgery was performed to staple or suture the peripheral tissues and suture the posterior cruciate ligament plus a synthetic reinforcement (Ligastric); the anterior cruciate ligament was not repaired. Immediate rehabilitation started with mobilisation 0°/60°up to day 21 then with 0°/90° up to day 60. The lower limb was immobilised in an extension brace and weight-bearing was encouraged starting on day 60.

Results: All patients were reviewed at consultation with stress radiographs. Mean follow-up was three years (two to six years). The IKDC score was recorded. Four patients had arthrolysis, one had an isolated reconstruction of the anterior cruciate ligament, one had an ablation of the synthetic ligament and repair of the anterior cruciate ligament. The 70° posterior drawer was 18° preoperatively and 9 mm at last follow-up (21–0 mm). The greatest laxity corresponded to a patient who had had ablation of the synthetic ligament. The Pudda index was 6 mm, mean mobility was 0/130°, and two patients had asymmetric 10° recurvtum. Subjective outcome was very satisfactory for seven patients, satisfactory for nine and disappointing for one.

Conclusion: The objective result can still be improved by correcting the posterior laxity. Not repairing the anterior cruciate ligament immediately does not worsen prognosis. There were no complications related to the synthetic ligament. This therapeutic attitude can be proposed for major knee trauma.

Purpose: Radiologists describe cysts of the anterior cruciate ligament (ACL) as a cystic formation of the cruciate tentorium. The estimated prevalence is 0.2 to 1.3% of patients explored by magnetic resonance imaging. The purpose of this study was to better define the clinical symptoms involved by comparing clinical, radiological and pathological findings.

Material and methods: Between February 1996 and April 2000, nine men underwent surgery of the anterior cruciate ligament for cysts. Mean age at surgery was 43 years (26) 54). None of the patients had a history of trauma and one patient had undergone medial meniscectomy 12 months earlier due to meniscosis. Pain had been present for six months to seven years and progressed slowly. It was very specifically related to hyperflexion. Five patients exhibited a moderate effusion and five had a painful joint line. The Lachmann was stiff. Single leg stance plain x-rays were normal. Magnetic resonance imaging demonstrated a poorly delimited heterogeneous destructured aspect of the ACL in seven patients. The suggested diagnosis was “partial tear of the ACL or old tear of the ACL”. A perfectly circumscribed cyst was revealed by the MRI in two cases, lying behind the ACL in the tentorium of the notch. The posterior cruciate ligament had a normal aspect in all cases.

Results: All patients underwent arthroscopy. The ACL was deorganised, widened and yellow in eight, with a yellow circumscribed nodule on the posterior aspect in one. An impingement between the ACL and the tentorium of the notch was observed in one case. Total synovectomy of the ACL sheath removing part of the ligamentous fibres was performed in eight cases. An isolated cyst was removed in one. Plasty of the notch was performed in one. Pathology reported degenerative dystrophic lesions in eight cases and haemopigmented villonodulary synovitis in one. All patients were reviewed at a mean follow-up of 14 months (8–48). Pain at hyperflexion had completely subsided and there was no hydrarthrosis. The Lachmann was stiff and symmetrical.

Conclusion: The term ACL cyst is probably inappropriate because we were unable to find true cystic formations but rather a spontaneous degenerative process. Synovectomy of the sheath gave good clinical results. MRI findings can be a diagnostic pitfall: a destructured aspect of the ACL without a context of trauma should suggest spontaneous degeneration of the anterior cruciate ligament.