Search

Introduction: Posterior tibial translation in total knee replacement (TKR) could be one major factor for PE wear, delamination and loosening of the tibial component due to increased shear forces and component-to-bone interface stress. The aim of this study was to assess the posterior stability of two different designs of posterior cruciate ligament (PCL) substituting TKR., Method: In this non-randomised consecutive study 43 patients underwent TKR for primary osteoarthritis. Twenty-six patients in group FB received a deep-dished fixed-bearing Duracon TKR (Howmedica, Rutherford, NJ, USA) and 17 patients in group MB a deep-dished rotating mobile-bearing Duracon TKR. In both groups the PCL was resected. All patients had pre- and postoperative kneeling stress radiographs and were clinically evaluated with the Knee Society Score. Posterior tibial translation was measured by tracing a line along the posterior tibial cortex in relationship to the posterior edge of Blumensaat's line., Results: The average follow-up was 13 months for group FB and 11 months for group MB. Both groups demonstrated a statistical significant increase of the mean posterior tibial translation on kneeling stress X-ray of 4.1 mm (group FB) (P < 0.001) and of 6.6 mm (group MB) (P < 0.001) compared to pre-operative. Group MB showed a significant higher posterior draw (P < 0.008). Clinical assessment using the Knee Society Score showed comparable short-term results., Conclusion: The deep-dished fixed-bearing TKR as well as the deep-dished rotating mobile-bearing TKR demonstrated significant posterior tibial translation on kneeling stress X-ray. It remains to be determined what amount of joint play is optimal for clinical function and to minimise shear forces and PE wear. Moreover the amount of posterior tibial translation was significantly higher with the mobile-bearing insert, which could be directly related to the asymmetric rotational mobility of the tibial insert. A long-term follow-up is necessary to investigate whether our findings correlate with the survival-rate of these specific implants.

The aim of this study was to assess the posterior stability of two different designs of total knee replacement (TKR) with deep-dished mobile bearing (MB) implants using stress X-rays. In a prospective non-randomized consecutive study, 34 patients with primary osteoarthritis of the knee underwent TKR. In group A (17 knees), they received a MB insert with a Duracon prosthesis and in group B (18 knees), a Genesis prosthesis. In all cases the posterior cruciate ligament (PCL) was resected. All patients had pre- and post-operative kneeling X-rays and were clinically evaluated with the Knee Society Score. Measurements on the radiographs were taken by tracing a line along the posterior cortex of the tibia and then measuring the perpendicular distance to a point marked at the posterior corner of Blumensaat's line. The average follow up was 10.7 months for group A and 5.4 months for group B. No statistical difference could be found in terms of clinical results and pre- and post-operative kneeling X-rays between the two groups. In each group, all knees demonstrated a significant posterior tibial translation postoperatively compare to their pre-operative status (p<0.0001). There are advantages in resecting the PCL in TKR: mobile flexion gap, correction of fixed deformity, more flexibility to adjust the joint line. The use of a deep dished polyethylene (PE) insert provides stability and use of MB insert reduces PE wear whilst retaining congruity. Two designs of deep-dished MB inserts showed significant posterior tibial translation on stress X-rays. It remains to be determined what amount of laxity is optimal for clinical function and polyethylene longevity.

We report the feasibility, indications, and usefulness of an arthroscopic approach to the posterior knee compartments. We developed an arthroscopic approach to the posterior knee compartment involving use of a posteromedial portal and a posterolateral portal opposite each other. Each posterior portal is used in alternation for the arthroscope and instruments. The posterior portals are established using an original "back and forth" technique. The feasibility of the technique was evaluated on a cadaver. It allowed us to define safety rules to protect the vessels and nerves that course through the popliteal fossa. The approach provided a broader field of view compared with classical techniques. After removal of the septum dividing the posterior compartment, the synovial fold enclosing the posterior cruciate ligament and lining the upper and posterior parts of the posterior capsule was readily accessed, suggesting that this approach may be particularly valuable for total synovectomy. This was confirmed in 6 patients with villonodular synovitis, in whom the new approach was used in combination with arthroscopic anterior synovectomy. This technique allows removal of parts of the synovium that are difficult to access through conventional arthroscopic approaches. For total synovectomy, it can be used as an alternative to open posterior synovectomy, in combination with arthroscopic anterior synovectomy.

Osteochondritis dissecans is a rare condition which occurs most frequently in the medial condyle of the knee. Its prognosis remains controversial. We report our experience with transchondral drilling (TCD) for osteochondritis dissecans. The rationale for this low-morbidity procedure is to enhance the healing potential of a lesion which failed to heal after conservative treatment. This multicenter retrospective study examined 24 patients (25 medial condyles), including cases both before (juvenile osteochondritis dissecans, JOCD; n=17) and after closure of the physis (adult osteochondritis dissecans, AOCD; n=8). All patients initially underwent a prolonged conservative treatment. The mean duration of symptoms prior to surgery was 22 months in JOCD and 55 months in AOCD patients. TCD was proposed in cases of intact or almost intact articular cartilage and was initially conducted under arthrotomy and later by arthroscopy. Mean follow-up time was 11.8 years in JOCD and 6 years in AOCD, and evaluation was based on clinical examination and radiography. Excellent clinical results were only observed in the JOCD group (12/17). In the AOCD group 4 patients had a good result and the other 4 a poor result. Radiological findings matched with clinical results. Except for age, factors of poor prognosis were: fissure of the articular cartilage and anterior extension of the lesion. We do not recommend TCD for AOCD. In JOCD, failure after 12 months of conservative treatment should indicate TCD in the cases where the cartilage remains continuous. At this stage there is no indication for more aggressive procedures.