Posterior capsular release is a biomechanically safe procedure to perform in total knee arthroplasty.

PURPOSE: Surgeons may attempt to strip the posterior capsule from its femoral attachment to overcome flexion contracture in total knee arthroplasty (TKA); however, it is unclear if this impacts anterior-posterior (AP) laxity of the implanted knee. The aim of the study was to investigate the effect of posterior capsular release on AP laxity in TKA, and compare this to the restraint from the posterior cruciate ligament (PCL). METHODS: Eight cadaveric knees were mounted in a six degree of freedom testing rig and tested at 0°, 30°, 60° and 90° flexion with ± 150 N AP force, with and without a 710 N axial compressive load. After the native knee was tested, a deep dished cruciate-retaining TKA was implanted and the tests were repeated. The PCL was then cut, followed by releasing the posterior capsule using a curved osteotome. RESULTS: With 0 N axial load applied, cutting the PCL as well as releasing the posterior capsule significantly increased posterior laxity compared to the native knee at all flexion angles, and CR TKA states at 30°, 60° and 90° (p < 0.05). However, no significant increase in laxity was found between cutting the PCL and subsequent PostCap release (n.s.). In anterior drawer, there was a significant increase of 1.4 mm between cutting the PCL and PostCap release at 0°, but not at any other flexion angles (p = 0.021). When a 710 N axial load was applied, there was no significant difference in anterior or posterior translation across the different knee states (n.s.). CONCLUSIONS: Posterior capsular release only caused a small change in AP laxity compared to cutting the PCL and, therefore, may not be considered detrimental to overall AP stability if performed during TKA surgery. LEVEL OF EVIDENCE: Controlled laboratory study.

[The prediction of growth in long bones in poliomyelitis (author's transl)]. / Difficultés de prévision de la croissance des os longs poliomyélitiques.

The authors have studied 15 cases of unilateral poliomyelitis and have compared the growth of the intact lower limb with that of the paralysed limb. It is concluded that no accurate prediction can be made except by multiple measurements. In most of the cases, growth was steady, the rate of shortening increasing by regular degrees. However, in very young children the degree of shortening was more consistent and was similar to that in congenital abnormalities.

[The jerk-test in external rotation in rupture of the anterior cruciate ligament. Description and significance]. / Le ressaut en rotation externe dans les ruptures du ligament croisé antérieur. Description et signification.

The authors describe a dynamic test of anterior subluxation of the tibia in lateral rotation in ruptures of the anterior cruciate ligament. This jerk-test in lateral rotation indicates general anterior laxity, including the posteromedial and posterolateral capsular structures. It is only present in lesions of the anterior cruciate ligament, and is only positive in 60 per cent. Its presence is a contra-indication to an isolated lateral extra-articular ligamentoplasty and an indication for intra-articular ligamentoplasty of the anterior cruciate ligament. This test must be distinguished from the Jacob reverse pivot shift test, which indicates posterolateral laxity.

[Total replacement of ankylosed hips (author's transl)]. / Arthroplastie totale sur hanche ankylosée.

31 patients were operated on using total hip replacement. Most of them had suffered an ankylosis of the hip in malposition, resulting in pain in the lumbar spine and knee. The average post-operative mobility was of 75 degrees of flexion. Stability returned to normal one year after operation. The pain in the lumbar spine was consistently improved, and could be completely relieved in cases without spinal arthrosis if it was of short duration. Pain in the knee was completely relieved in cases where the procedure restored a satisfactory bio-mechanical state. 29 patients were reviewed, of which 25 were satisfactory.

[Anterior cruciate ligament reconstruction: biomechanical comparison on cadaver specimens using a single or double hamstring technique]. / Reconstruction du ligament croisé antérieur par greffe de tendons de la patte d'oie à un ou à deux faisceaux: comparaison biomécanique sur genoux cadavériques.

PURPOSE OF THE STUDY: We worked with cadaver specimens to evaluate control of anterior knee laxity after reconstruction of the anterior cruciate ligament (ACL) comparing double two-strand anterolateral and posteromedial reconstruction with the classical four-strand technique. We hypothesized that the double reconstruction would provide better control of anterior laxity in both flexion and extension. MATERIAL AND METHODS: Sixteen cadaver knees were randomly assigned to reconstruction technique. Anterior tibial translation was measured with an arthrometer (Rolimeter) at maximal manual tension at 20 degrees, 60 degrees and 90 degrees flexion on the intact knee, after section of the ACL and after arthroscopic reconstruction using either the classical four-strand hamstring technique or a double two-strand anteromedial and posterolateral technique. An EndoButtonCL was used for the femoral fixation and a interference screw with staples for the tibial fixation. Variation in the length of each construct was measured between 0 degrees and 90 degrees flexion. RESULTS: In the single reconstruction group, the length of the graft varied by 0.5 +/- 0.7 mm between 0 degrees and 90 degrees flexion. In the double reconstruction group, the length varied by 0.5 +/- 0.9 mm for the anteromedial construct and 3.4 +/- 0.5 mm for the posterolateral construct. When studied with an intact ACL, anterior laxity of the 16 knees was 3.2 +/- 1.1, 3.5 +/- 1.5 and 2.6 +/- 1.1 mm at 20 degrees, 60 degrees, and 90 degrees respectively. After section of the ACL, laxity increased significantly at all angles: 9.4 +/- 3.3, 6.1 +/- 2.5 and 6.8 +/- 2.9 at 20 degrees, 60 degrees, and 90 degrees respectively. After classical four-strand single graft reconstruction, the residual anterior laxity was 3.7 +/- 0.9, 3.1 +/- 1.1, and 2.3 +/- 1.6 mm at 20 degrees, 60 degrees, and 90 degrees flexion. Statistical analysis using parametric or non-parametric tests as appropriate showed a significant difference in laxity at 20 degrees, 60 degrees, and 90 degrees of flexion between knees with a cut ACL and knees with reconstructed ACL. At 20 degrees flexion, residual laxity was greater after single-construct reconstruction. At 60 degrees and 90 degrees there was no significant difference in anterior translation of the tibia in knees with intact or reconstructed ACL. After reconstruction with the dual-construct technique, laxity was 3.4 +/- 1.3, 2.6 +/- 1.5, and 2.4 +/- 1.2 mm at 20 degrees, 60 degrees and 90 degrees flexion respectively. Laxity was significantly greater with a cut ACL than after reconstruction at 20 degrees, 60 degrees, and 90 degrees flexion, but there was no significant difference in anterior translation of the tibia at 20 degrees, 60 degrees, and 90 degrees flexion between knees with an intact and a reconstructed ACL. DISCUSSION: These results based on a clinical evaluation measuring anterior translation of the tibia with an arthrometer are in agreement with results in the literature using robots. Compared with the classical technique, reconstruction of the ACL with a dual-construct technique provides a statistically significant improvement in control of anterior tibial translation at 20 degrees of flexion. The advantage of the dual anteromedial and posteriolateral construct technique is thus not found in the control of anterior laxity but rather in control of rotation laxity. CONCLUSION: Reconstruction of the ACL with a two-bundle graft technique provides control of anterior laxity at 20 degrees, 60 degrees, and 90 degrees flexion similar to that observed in knees with an intact ACL while the single construct technique re-establishes physiological laxity at 60 degrees and 90 degrees only. This improved control of anterior laxity with the two-bundle reconstruction is a small improvement regarding anterior laxity, the more potential advantage concerning rotational stability.

Lateral discoid menisci in children.

In children, the snapping-knee syndrome is strongly suggestive of a diagnosis of discoid menisci; alternatively, the loss of physiological hyperextension of the knee suggests a diagnosis of a torn lateral discoid meniscus. We used arthroscopic meniscectomy to treat 19 lateral discoid menisci in 16 children (average age, 10.5 years). Excellent results were achieved in 18 of 19 cases, with disappearance of the snapping with knee flexion (maximum follow-up, 3 years).