Aims

Hip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane.

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.

Purpose of the study: Cysts are rarely identified in the anterior cruciate ligament; the pathogenic mechanisms involved are poorly understood. We investigated the anatomic and clinical presentation.

Material and methods: This retrospective analysis included 24 patients, seven women and seventeen men managed in a single center from 1998 to 2004. Mean patient age was 45 years (range 25–74 years). All patients complained of pain. A preoperative MRI was available for all patients. Mean follow-up was 25 months (range 6–48 months). Arthroscopic procedures were used for 17 patients and the IKDC subjective score was determined preoperatively in all. Radioguided (US or CT) puncture was performed for seven patients associated with corticosteroid injections.

Results: On the MRI, there were 16 infiltrating cysts and eight cystic formations. Surgical treatment (n=17) was performed for 13 infiltrative cysts and for four cystic formations. There were two cases of recurrence. Outcome was poor after puncture (two puncture failures, three recurrences and one vascular complication).

Discussion: Two forms of cysts of the ACL can be demonstrated by MRI. The clinical presentation may not be different but the therapeutic management should be. The cystic formation is an indication for puncture, with arthroscopic treatment in the event of failure. For infiltrating cysts, complete resection of the cyst during an arthroscopic procedure is indicated, sometimes associated with resection of the ACL. Puncture yields poor results.

Purpose of the study: The purpose of this retrospective study was to analyze clinical datao n pigmented villon-odular synovitis (PVSN) of the knee as well as outcome after treatment in order to define the diagnostic stages, the surgical treatment, and follow-up modalities for this rare benign proliferative disease of the synovial which predominantly affects the knee joint.

Material and methods: Between 1996 and 2004, 28 patients were managed in our department, 13 men and 15 women, diffuse PVNS in 20 and localized PVNS in 8. IN the localized forms, symptoms were similar to those observed in knees with intra-articular foreign bodies or a meniscal lesion (75%) was present for 14 months on average at the first consultation. Mean age at onset of therapeutic management was 40 years (range 20–62). Localized arthroscopic or open resection was performed. For the diffuse forms, symptoms had been present for 15 months on average at the first consultation. Patients sought medical care because of spontaneous hemarthrosis or diffuse knee pain with no specific signs. Mean age at onset of therapeutic management was 38 years (range 15–59). Bony lesions were observed in 20%. Synoviorthesis or surgical synovectomy were performed. Mean follow-up was 97 months (range 12–309). Outcome was analyzed separately for the localized and diffuse forms.

Results: For the localized PVNS, there were no complications after surgical treatment but the relapse rate reached 12.5%. For diffuse PVNS, the cumulative rate of relapse was 50%, recurrence being noted on average 37 months after treatment. A stiff joint developed in 14% after open synovectomy. Surgical treatment was necessary in four cases (total arthroplasty in three) seen late after development of bony lesions; the clinical outcome was good with good gain in flexion.

Discussion: MRI is essential for the topographic diagnosis and to guide surgery. For diffuse PVNS seen at an advanced stage or after several recurrences, adjuvant synoviorthesis can be useful 4 to 8 months after surgery.

Conclusion: Appropriate treatment of PVNS of the knee depends on the presentation but usually involves a surgical procedure. The risk of recurrence for diffuse PVNS warrants annual MRI for four years.

Purpose of the study: The objective of this study was to compare outcome after total knee arthroplasty (TKA) with a metallic tibial base versus full poly prostheses.

Material and methods: This monocentric retrospective study compared 169 Tornier full poly HLS TKA (group A) with 169 TKA with a fixed metallic tibial base (group B). The two series were matched for age, gender and etiology. Mean age was 71 years and female gender predominated, 80%. Mean follow-up was 66 months. Clinical (IKS score) and radiological outcome was assessed. Statview 5.0™ was used for the statistical analysis, Student’s t test for quantitative variables and chi-square test for qualitative variables. Differences were considered significant for p< 0.05. The beta factor was 0.2.

Results: The main intraoperative incidents were, weakening of the popliteal tendon (n=1) and supra and inter-condylar fracture of the femur (n=1) in group A patients and weakening of the popliteal tendon (n=2) and secondary fracture line of the medial tibial plateau (n=2) in group B patients. For group A, the knee score was 89±10.82 (mean±SD) and for group B 88.28±11.94. The function score was 68±23.75 for group A and 71±24.05 for group B. Mean flexion in both groups was 113°. Non-progressive tibial lucent lines were observed in 27 patients in group A and in 23 in group B. There were 7 replacements of the TKA in group A and 6 in group B. Survival for group A was 94.5% and 93.64% for group B.

Discussion: There were no significant differences concerning function and knee scores, presence of lucent lines and prosthesis replacement between the two series (p> 0.05).

Conclusion: This study did not demonstrate a superiority of the metallic tibial base TKA at five years follow-up. Use of a full poly TKA could decrease the medical cost by more than 30%.