Rémi Philippot

Pelvic balance in sagittal and Lewinnek reference planes in the standing, supine and sitting positions.

INTRODUCTION Sagittal pelvic balance is a recognized factor influencing targeted acetabular-component anteversion during total hip arthroplasty implantation. However, no studies in the literature have systematically reported pelvic parameters data in the standing, sitting and supine positions. HYPOTHESIS Variations in acetabular cup orientation can be traced to eventual pelvic balance changes in one of these three usual positions. MATERIALS AND METHODS In these three positions (supine, standing and sitting), pelvic anatomical parameters and reference planes were radiologically defined from a group of 67 patients (average age: 70.2+/-3.2 years). The complete X-rays individual sets were digitized and measurements were obtained by a single operator using a Spineview software (previously, strictly validated for these kind of measurements). Positioning according to the Lewinnek pelvic coordinate system, which is considered as a possible source of errors when vertically standing or horizontally lying, was also investigated. RESULTS The average pelvic incidence of 59.6 degrees did not vary in the sitting, supine or standing positions, with no statistically significant difference between sexes. The Legaye equation--pelvic incidence is equals to pelvic version plus sacral slope--was verified. Pelvic version increased by an average 22 degrees from the sitting to the supine or standing positions. Sacral slope varied in a reverse order. Pelvic-femoral angle (PFA) decreased by 20 degrees from the standing to the supine position. The Lewinnek plane was located 4 degrees posterior to the vertical plane. Whatever the position adopted, pelvi-Lewinnek angle appeared constant, averaging 12 degrees. DISCUSSION The average pelvic incidence in this series was high, most probably associated with advancing patient age and/or pathology. The concept of functional anteversion appeared critical when taking into account pelvic version variations (according to the position, sitting, supine or standing) positions. The Lewinnek plane, commonly accepted as the reference plane for hip navigation, was individualised to each patient and should not be mistaken with the vertical plane; positioning of the femur in relation to the Lewinnek plane was also specific to each patient. Cumulative approximation on these two parameters at surgery resulted in a combined imprecision of 26 degrees when standing and 36 degrees when lying down. We have thus defined crucial parameters to be integrated in computer-assisted hip surgery softwares: positional variations of the pelvic version (functional anteversion), positioning of the Lewinnek plane, and PFA value (both specifically patients dependant). If integration of these parameters into new sofwares versions appears possible, this would represent a reliable compromise between maximum prosthetic stability, maximum joint amplitudes and elimination of possible prosthetic conflict.

The role of the medial ligamentous structures on patellar tracking during knee flexion

PurposeThe influence of the medial patellar ligamentous structures on patellar tracking has rarely been studied. Thus the main purpose of this cadaveric biomechanical study was to determine the influence of the medial patellofemoral (MPFL), medial patellomeniscal (MPML) and medial patellotibial (MPTL) ligaments on the three-dimensional patellar tracking during knee flexion. This study was conducted using a validated cadaveric optoelectronic protocol for analysis of patellar kinematics.MethodsFor each cadaveric knee study, four successive acquisitions were performed; first was studied patellar tracking in healthy knees, then the junction between MPFL and vastus medialis obliquus (VMO) was sectioned, the MPFL was released at its patellar attachment and finally was released the insertion of the MPML and MPTL.ResultsIn this study, the MPFL accounts for 50–60% of the medial stabilization forces of the lateral patellar shift during patellar engagement in the femoral trochlea. This work confirm and clarify the role of the MPFL as the primary stabilizer of the patella during the initial 30° of knee flexion. Moreover, this study shows no significant results regarding the stabilizing action of the VMO on the patella during knee flexion.ConclusionThis in vitro study, conducted with an experimental protocol previously validated in the literature, helps quantify the actions of the MPFL, the VMO, and the MPML/MPTL respectively, and identify areas of joint motion where these structures have the most significant influence. This confirms the importance of reconstruction in the treatment of chronic patellar instability. During its reconstruction, care should be taken to adjust the MPFL balance during the initial 20°–30° of flexion.

Survival of cementless dual mobility socket with a mean 17 years follow-up

PURPOSE OF THE STUDY As part of the 2006 symposium of the French Hip and Knee Society devoted to the dual mobility socket, we report a retrospective multicentric series of 438 first-intention total hip prostheses with a dual mobility socket at a mean 17 years follow-up. The purpose of our report was to ascertain the 15-year survival of this socket and analyze failures. MATERIAL AND METHODS The series included 438 primary replacements. This was a homogeneous multicentric series. The cementless sockets were 80 Novae-1 titanium Serf cups and 358 Novae-1 stainless steel Serf cups. All stems were inserted without cement: 185 Pf((R)) stainless steel screwed Serf stems, 228 PRO titanium screwed Serf stems, and 25 Corail stems. The mobile polyethylene insert was retaining. All of the heads were 22.2-mm chromium-cobalt heads. Degenerative hip disease was the main etiology and mean follow-up was 17 years (range, 12-20). Mean age at implantation was 54.8 years (range, 23-87). The actuarial method with a 95% confidence interval was used to determine the 15-year cup survival rate. RESULTS At the last follow-up, none of the patients had presented an episode of early or late instability. Analysis of the socket at last follow-up showed 13 aseptic loosenings, 23 intraprosthetic dislocations, and seven replacements of the polyethylene insert for wear. The overall 15-year prosthesis survival rate was 89.2+/-8.7%. The overall 15-year socket survival rate was 96.3+/-3.7%. DISCUSSION The fact that, at last follow-up, none of the implants had shown instability confirms the long-term stability of the dual mobility socket. The results in terms of 15-year survival confirm earlier reports. The main cause of failure was cup fixation, which is the weak point of this technique with the initial Novae cup design, which did not have hydroxyapatite coating. The second leading cause was intraprosthetic dislocation, which can be divided into three main categories. The first is intraprosthetic dislocation in a context of pure wear with normal function of the dual mobility socket; the retaining feature of the insert loses its efficacy due to wear. The second category is intraprosthetic dislocation in a context of cup loosening with a third-body effect and increased retention wear, in which case we consider that cup loosening is the primary event leading to rapid secondary wear and subsequent intraprosthetic dislocation. The third category is intraprosthetic dislocation caused by a blockage in a context of fibrosis or impingement involving severe heterotopic ossifications. We had only two femoral failures related to aseptic loosening, most certainly related to use of noncemented implants, which limits the extension of granulomas to the polyethylene. Studying the three series from Saint-Etienne more specifically, where three different configurations were used, it would appear that the titanium cup has a better survival rate and that the titanium used for the thinner necks may be an unfavorable factor for intraprosthetic dislocation.

Étude d'une série de 438 cupules non cimentées à double mobilité

PURPOSE OF THE STUDY Within the framework of the 2007 symposium of the French Hip and Knee Society devoted to the dual mobility socket, we report a retrospective multicentric series of 438 first-intention total hip prostheses with a dual mobile socket at 17 years mean follow-up. The purpose of our report was to ascertain the 15-year survival and analyze failures. MATERIAL AND METHODS The series included 438 first-intention prostheses. This was a homogeneous multicentric series. Sockets were: 80 Novae-1 titanium Serf cups and 358 Novae-1 stainless steel Serf cups. All stems were inserted without cement: 185 Pf) stainless steel screwed Serf stems, 228 PRO titanium screwed Serf stems, 25 Corail stems. The mobile polyethylene insert was retaining. All of the heads were 22.2mm chromium-cobalt heads. Degenerative hip disease was the main etiology and mean follow-up was 17.18 years (range: 12-20). Mean age at implantation was 54.8 years (range: 23-87). The actuarial method with 95% interval of confidence was used to determine the 15-year cup survival. RESULTS At last follow-up, none of the patients had presented an episode of early or late instability. Analysis of the socket at last follow-up showed: 13 aseptic loosenings, 23 intraprosthetic dislocations, and seven replacements of the polyethylene insert for wear. The overall 15-year prosthesis survival was 89.2+/-8.7%. The overall 15-year socket survival was 96.3+/-3.7%. DISCUSSION The fact that at last follow-up none of the implants had exhibited instability confirms the long-term stability of the dual mobility socket. The results in terms of 15-year survival confirm earlier reports. The main cause of failure was cup fixation, which is the weak point of this technique with the initial Novae cup, which did not have hydroxyapatite coating. The second leading cause was intraprosthetic dislocation, which can be divided into three main categories. The first is intraprosthetic dislocation in a context of pure wear with normal function of the dual mobility; the retaining feature of the insert looses its efficacy due to wear. The second category is intraprosthetic dislocation in a context of cup loosening with a third-body effect and increased retention wear, in which case we consider that the cup loosening is the primary event leading to secondary rapid wear and subsequent intraprosthetic dislocation. The third category is intraprosthetic dislocation cause by a cam effect in a context of fibrosis or impingement involving a large calcification. We have had only two femoral failures by aseptic loosening, most certainly related to use of noncemented implants, which limits the extension of granulomas to the polyethylene. Studying more specifically the three series from Saint-Etienne where three different configurations were used, it would appear that the titanium cup has a better survival and that the titanium used for the thinner necks would be an unfavorable factor for intraprosthetic dislocation.

Repeat Revision of Anterior Cruciate Ligament Reconstruction A Retrospective Review of Management and Outcome of 10 Patients With an Average 3-Year Follow-Up

Background To the authors’ knowledge, no previous published study has focused on management and outcome of repeat revision of anterior cruciate ligament reconstruction in terms of functional result and meniscus and articular cartilage status. Hypothesis Repeat revision of anterior cruciate ligament reconstruction improves knee stability, but with inferior results for functional outcome compared with primary anterior cruciate ligament reconstruction. Meniscal tears and subsequent articular cartilage degeneration are more prevalent with successive revisions due to recurrent laxity. Study Design Case series; Level of evidence, 4. Materials and Methods: Between February 2003 and November 2006, a consecutive series of 10 patients with an average age at 30 years (range, 17-48) were operated on for a repeat revision of anterior cruciate ligament reconstruction (2 revisions after a primary reconstruction) with arthroscopic procedures. A clinical and a radiographic evaluation were performed to assess anterior cruciate ligament reconstruction failures, outcome of revisions, and causes of failures. Meniscal tears and articular cartilage lesions were analyzed. Results The average follow-up of the second revision was 38 months (range, 12-61). At latest follow-up, final International Knee Documentation Committee assessment was excellent or good in 7 cases. Postoperatively, only 2 patients recovered to the same sports activity level they had before their first anterior cruciate ligament reconstruction. Four had a lower level, and 4 discontinued sports activity. The postoperative average side-to-side KT-1000 arthrometer maximum manual difference was 1.3 ± 1.9 mm. Nine patients had meniscal tears and 7 had articular cartilage lesions. Meniscal tears, meniscectomies, and articular cartilage degeneration increased after the second revision (P = .016, P = .0098, and P = .0197, respectively). Severe articular cartilage degeneration (International Cartilage Repair Society grade III and IV lesions) was found in patients with bad functional outcome (final International Knee Documentation Committee assessment C or D) (P = .0472). Incidence of articular cartilage degeneration was found to be more prevalent in cases of meniscal tears and partial meniscectomy at the same tibiofemoral compartment (P = .0157). Index anterior cruciate ligament reconstruction and first revision failures were caused by recurrent trauma (60% and 70%, respectively) or a surgical technical error with tunnel malpositioning (40% and 10%, respectively). Conclusion Outcome of repeat revision of anterior cruciate ligament reconstruction was excellent or good in 70% of the cases, although decreased after the second revision, in relation to the occurrence of meniscal tears and articular cartilage lesions. Meniscal and articular cartilage lesions were more frequent and more severe with recurrent laxity. The cause of failures was mainly recurrent trauma, followed by surgical technical errors.

Study of patellar kinematics after reconstruction of the medial patellofemoral ligament.

BACKGROUND Medial patellofemoral ligament reconstruction is currently the technique of choice for the treatment of patellar instability. But what should be the most appropriate graft tension for optimal restoration of patellofemoral kinematics? METHODS Six freshly frozen cadaveric knees were studied, the three bone segments were respectively equipped with opto-reflective markers. The acquisitions were made using the Motion Analysis System®. Six successive acquisitions were performed for each knee under different levels of graft tension. FINDINGS With an intact medial patellofemoral ligament, the medial patellar tilt increased up to a mean value of 2.02° (SD 3.1), the medial patellar translation gradually increased up to a mean value of 3.3mm (SD 2.25) with a slight lateral rotation over the first 30° of knee flexion with a maximum mean value of 1.22° (SD 0.8) at 20° of knee flexion. Reconstruction of the medial patellofemoral ligament was performed using different levels of tension applied to the graft. Only 10 N of graft tension could restore normal patellar tilt, lateral shift and rotation, with results approximating those measured on healthy knee. INTERPRETATION This study confirms the role of the medial patellofemoral ligament in providing adequate patellar stability during the first 30° of knee flexion. According to our findings, a 10 N tension applied to the graft appears sufficient to ensure proper control of patellar tracking whereas 20, 30 and 40 N of tension are excessive tension values inducing a major overcorrection in all studied parameters.

Repair of insertional achilles tendinosis with a bone-quadriceps tendon graft

Background: While conservative treatment may be successful in most cases, partial rupture at the calcaneal insertion point is a significant concern with insertional Achilles tendinopathy. We report on the outcomes of a surgical technique for Achilles tendon augmentation using a bone-tendon graft harvested from the knee extensor system. Materials and Methods: Our retrospective case series includes 25 surgical procedures performed in 24 patients, 19 males and five females, with a mean age of 47 (range, 30 to 59) years, 18 of whom were athletes. The mean followup period was 52 (range, 12 to 156) months. All patients underwent MRI examination prior to surgery which showed partial Achilles tendon rupture. The Achilles tendon was debrided through a posterolateral approach. The bone-quadriceps tendon graft was harvested, then the bone plug of the graft was inserted into a blind tunnel drilled into the calcaneus and fixed with an interference screw. The fibers of the quadriceps tendon were sutured to the residual part of the Achilles tendon with the foot at an angle of 90 degrees. Results: Patients were able to resume their sporting activity after an average of 6.7 months. At last followup examination, physical activity was scored 5.2 on the 10-point Tegner Scale; the mean AOFAS score was 98.4. MRI examination showed good graft integration 1 year postoperatively. Conclusion: The bone-quadriceps tendon grafting technique was a good alternative for the insertional Achilles lesions with partial detachment which we felt required augmentation. Level of Evidence: IV, Retrospective Case Series

The anterolateral ligament: Anatomic implications for its reconstruction

BACKGROUND The purpose of this study was to define the best anatomic parameters with which to perform an accurate anterolateral ligament (ALL) reconstruction. These parameters were anatomical insertions, allowing favorable isometry, length variation during flexion, and anthropometric predictors of ALL lengths. METHODS A total of 84 fresh-frozen cadaver knees were dissected to analyze the ALL, focusing on its femoral insertion. The ALL length was measured in different degrees of flexion (extension, 30°, 60°, and 90° of flexion) and rotation (neutral, internal or external rotation). The ALL width and thickness were measured. A correlation between ALL length, the general knee size and individual characteristics was investigated. RESULTS The ALL was present in 80 specimens (95%). The femoral footprint was always posterior (5.52±0.93 mm, range 3.83-6.94) and slightly proximal (1.51±0.75mm, range 0.63-2.37) to the lateral femoral epicondyle. The mean ALL length increased with internal rotation and decreased with external rotation (P<0.05). The maximum ALL length was found at 30° of flexion, and the minimum at 90°. There was a significant correlation between the ALL length and height, sex, and proximal femur dimensions. CONCLUSION In order to get an anatomical reconstruction with favorable isometry, it is recommended that the ALL femoral graft is implanted posterior and slightly proximal to the epicondyle. It is also suggested that the tension be adjusted by fixing the graft between 0 and 30° of flexion, being tighter near extension. This will allow good rotational stability without implying any stiffness.

Repeat Revision of Anterior Cruciate Ligament Reconstruction

Background To the authors’ knowledge, no previous published study has focused on management and outcome of repeat revision of anterior cruciate ligament reconstruction in terms of functional result and meniscus and articular cartilage status. Hypothesis Repeat revision of anterior cruciate ligament reconstruction improves knee stability, but with inferior results for functional outcome compared with primary anterior cruciate ligament reconstruction. Meniscal tears and subsequent articular cartilage degeneration are more prevalent with successive revisions due to recurrent laxity. Study Design Case series; Level of evidence, 4. Materials and Methods: Between February 2003 and November 2006, a consecutive series of 10 patients with an average age at 30 years (range, 17-48) were operated on for a repeat revision of anterior cruciate ligament reconstruction (2 revisions after a primary reconstruction) with arthroscopic procedures. A clinical and a radiographic evaluation were performed to assess anterior cruciate ligament reconstruction failures, outcome of revisions, and causes of failures. Meniscal tears and articular cartilage lesions were analyzed. Results The average follow-up of the second revision was 38 months (range, 12-61). At latest follow-up, final International Knee Documentation Committee assessment was excellent or good in 7 cases. Postoperatively, only 2 patients recovered to the same sports activity level they had before their first anterior cruciate ligament reconstruction. Four had a lower level, and 4 discontinued sports activity. The postoperative average side-to-side KT-1000 arthrometer maximum manual difference was 1.3 ± 1.9 mm. Nine patients had meniscal tears and 7 had articular cartilage lesions. Meniscal tears, meniscectomies, and articular cartilage degeneration increased after the second revision (P = .016, P = .0098, and P = .0197, respectively). Severe articular cartilage degeneration (International Cartilage Repair Society grade III and IV lesions) was found in patients with bad functional outcome (final International Knee Documentation Committee assessment C or D) (P = .0472). Incidence of articular cartilage degeneration was found to be more prevalent in cases of meniscal tears and partial meniscectomy at the same tibiofemoral compartment (P = .0157). Index anterior cruciate ligament reconstruction and first revision failures were caused by recurrent trauma (60% and 70%, respectively) or a surgical technical error with tunnel malpositioning (40% and 10%, respectively). Conclusion Outcome of repeat revision of anterior cruciate ligament reconstruction was excellent or good in 70% of the cases, although decreased after the second revision, in relation to the occurrence of meniscal tears and articular cartilage lesions. Meniscal and articular cartilage lesions were more frequent and more severe with recurrent laxity. The cause of failures was mainly recurrent trauma, followed by surgical technical errors.

[Five-year follow-up of a hydroxyapatite coated stem].

PURPOSE OF THE STUDY We studied a cementless anatomic stem combination with a cementless press-fit cup. The purpose of this work was to assess prospectively in a homogeneous consecutive series of patients, the clinical and radiological outcome of this prosthesis at five years follow-up. MATERIAL AND METHODS The series included 176 hips with a total hip arthroplasty implanted between September 1997 and December 1998 by the same surgeon through an antero-lateral approach (Watson-Jones). We retained for study first intention implantations for primary or secondary joint degeneration. Fractures and revisions were excluded from the analysis. At last follow-up the survival was 93.2%. Patients were revised clinically (satisfaction Harris score). An independent surgeon unaware of the clinical results performed the radiological analysis (Engh and Ara score, Brooker classification). The Kaplan-Meier method was used for the survival curve expressed with 95% confidence interval and considering revision for all causes as failure. RESULTS The five-year survival of the prosthesis was 98.8%. Clinically, the Harris score varied significantly (p<0.0001) from 32.9+/-1.2 preoperatively to 93.1+/-0.8 at last follow-up. Among the score items, pain exhibited the greatest improvement since at five years only, 10.2% of patients complained of mild pain. Thigh pain, often associated with cementless stems, was very low, 1.3%. Radiologically, the femoral implant was very stable with excellent bone remodelling as illustrated by the high Engh and Ara scores, 20.7+/-0.5 and 5+/-0.2 respectively. Polyethylene wear, 0.075mm/year, was below the usually observed levels. We noted a high rate of heterotopic ossifications, 65.1%, most Brooker I. DISCUSSION The SPS stem has shown good results at five years, both clinically and radiographically. The objectives of a stable fixation over time and harmonious remodelling appear to be achieved. These promising results should be reexamined in a series with a longer follow-up.