Attilio Speranza

Learning curve in tissue sparing total hip replacement: comparison between different approaches

BackgroundThe tissue sparing surgery (TSS) concept means not only smaller incisions but also less tissue disruption, allowing decreased blood loss and improved function. However, TSS techniques can result in more complications related to the learning curve. The aim of this study was to compare the learning curve of an experienced surgeon with different TSS approaches for total hip replacement (THR) from a clinical and surgical point of view, focussing especially on complications related to the use of different geometric stems.Materials and methodsSixty patients scheduled to be operated for a primary THR were enrolled in the study and were randomly assigned to surgery by one of three different TSS approaches: lateral with mini incision (group A), minimally invasive anterior (group B) and minimally invasive antero-lateral (group C). Results from the three TSS groups were compared with a control group of 149 patients (group D).ResultsOur results reveal significantly reduced blood loss in the TSS groups compared with the control group, with no differences between the TSS groups. We found better early functional scores in the two minimally invasive groups (anterior and anterolateral), and a lower rate of complications with the antero-lateral TSS approach.ConclusionThe antero-lateral TSS approach seems to be safer and less demanding than standard THR surgery, and is suitable for use with different stems.

Biomechanical evaluation of different anterior cruciate ligament fixation techniques for hamstring graft

BackgroundA number of anterior cruciate ligament (ACL) fixation techniques are currently in use. Slippage or failure of the graft by excessive loading or aggressive rehabilitation may result in an unstable knee. Load and slippage of the ACL graft varies according to the fixation technique used.MethodsGraft slippage, load to failure, and stiffness were evaluated using an animal model. Six soft tissue ACL fixation techniques and bone cement as a fixation device were tested: group A, Endo Button CL-Bio RCI; group B, Swing Bridge-Evolgate; group C, Rigidfix-Intrafix; group D, Bone Mulch-Washer Lock; group E, Transfix-Retroscrew; group F, Transfix-Deltascrew; group G, Kryptonite bone cement. Maximum failure load, stiffness, and slippage at the 1st and 1000th cycles and mode of failure were evaluated.ResultsThe maximum failure load was significantly higher in group B (1030 N) and significantly lower in group E (483 N) than in the others. The stiffness of group B (270 N/mm) was significantly higher than the others. As for the mode of failure, group C showed failure in the femoral side in all tests (four device ruptures and two tendon ruptures on the femoral side). All failures of the other groups occurred on the tibial side except one test in group A. All failures in group G were due to slippage of the tendons.ConclusionLoad to failure and stiffness was significantly different between the ACL fixation techniques. All but one of the fixation techniques showed sufficient properties for adequate postoperative rehabilitation. Bone cement used as a fixation device in soft tissue grafts did not seem to provide adequate initial fixation suitable for early rehabilitation after ACL reconstruction.

Navigated knee kinematics after tear of the ACL and its secondary restraints: preliminary results.

In this study we evaluated the role of the anterior cruciate ligament (ACL) and its secondary restraint in controlling knee stability using a navigation system. The purpose of this study was to evaluate the kinematics of the knee in different conditions of instability: ACL intact, after transection of the posterolateral (PL) bundle, after transection of the anteromedial (AM) bundle, and after lesion of the anterolateral femorotibial ligament (ALFTL). Anterior tibial translation and rotation were measured with a computer navigation system in 6 knees in whole fresh-frozen human cadavers by use of a manual maximum load. Anterior translation was evaluated at 30°, 60°, and 90° of flexion; rotation at 0°, 15°, 30°, 45°, 60°, and 90° of flexion. Cutting the PL bundle does not increase anterior translation and rotation of the knee. Cutting the AM bundle significantly increased the anteroposterior (AP) translation at 30° and 60° of flexion (P=.01), but does not increase rotation of the knee. Cutting the ALFTL increased anterior translation at 60° of flexion (P=.04) and rotation at 30°, 45°, and 60° of flexion (P=.03). The PL bundle does not affect anterior translation and rotation of the knee. The AM bundle is the primary restraint of the anterior translation but does not affect rotation of the knee. The lateral compartment becomes the primary restraint of rotation after ACL cut. The primary kinematic effect of an ACL injury is an increase in anterior tibial translation, but there is no significant change in maximum internal or external rotation. The lesion of the ALFTL increases tibial rotation and could be correlated to the pivot shift phenomenon.

Clinical and radiological outcomes of postoperative septic arthritis after anterior cruciate ligament reconstruction

BackgroundSeptic arthritis after arthroscopic anterior cruciate ligament (ACL) reconstruction is a rare complication. In the literature, several treatments have been proposed. The aim of the study was to report our results using ambulatory irrigation of the knee and parenteral and oral antibiotics.MethodsFrom January 2001 to December 2008, a total of 12 patients were treated for postoperative septic arthritis of the knee after ACL reconstruction in our hospital. The average age at trauma was 24 years (range 16–43 years). The treatment protocol included irrigation of the knee (for 2 days) and parenteral antibiotics and oral antibiotics subsequently. Repetitive irrigation was performed if necessary. The average duration of follow-up for our series was 38 months (range 6–54 months). Follow-up included International Knee Documentation Committee (IKDC) forms, radiography, Tegner and Lysholm scores, and KT-1000 arthrometric evaluation.ResultsIn all cases treatment of infection was successful. Neither graft nor hardware removal was needed in any of the cases. At final examination, the pivot shift was negative in 10 of 12 patients, and it was 1+ in the other 2 patients; the Lachman was negative in all cases. The mean postoperative Tegner score was 7.2, and the mean Lysholm score was 98.3. In all, 10 of the 12 patients were graded as group A and the other 2 as group B using the IKDC form. The mean postoperative manual maximum KT-1000 side-to-side difference was 2.3. No significant bone tunnel enlargement was found at radiographic evaluation.ConclusionsThe described treatment regimen gives reliable results for this complication. There were no recurrences of septic arthritis or bone infection. No further surgeries were required, and the graft was retained during the treatment of septic arthritis.

A lateral minimal-incision technicque in total hip replacement: a prospective, randomizes, controlled trial

Minimally invasive surgery has become a trend over the last few years in all aspects of orthopaedic surgery, including total hip arthroplasty. So-called mini-incision techniques involve limiting the length of the skin incision to 10 cm with use of either an anterior, lateral or posterior approach. Between March 2004 and December 2005 one hundred consecutive unilateral total hip replacements were performed by the same senior surgeon in our institute. All patients were randomly assigned to study group (group A) or control group (group B). In group A (50 patients) the skin incision was 8 cm; in group B (50 patients) the skin incision was standard (about 12-14 cm). Patient demographic data, including sex, age, height, weight, BMI, diagnosis and preoperative Harris hip score were recorded. Other criteria evaluated included the perioperative and postoperative complications, the surgical time, the blood loss, the length of the incision, the acetabular and stem positions, the length of hospital stay, Harris Hip Score (HHS) and the WOMAC osteoarthritis index at six months. No significant differences were found between the groups with respect to the average surgical time, the acetabular and stem position, the length of hospital stay and the Harris Hip Score (HHS) and the WOMAC osteoarthritis index at six months. A significant lower blood loss was found in the mini-incision group. A higher percentage of peri-operative complications was recorded in Group A (two stupor of sciatic nerve and one fracture of the greater trochanter). On the basis of our experience we could speculate that minimally invasive surgery should be directed to the new surgical approach with muscle sparing, instead of a shorter skin incision using standard approaches.

Reliability of cup position in navigated THA in the lateral decubitus position using the ‘flip technique’

Malpositioning of the acetabular component in total hip arthroplasty (THA) increases the risk of dislocation, reduces the range of motion and may contribute to bearing surface wear. During computer assisted navigation, the anterior pelvic plane is registered intraoperatively by percutaneous palpation, but this may be unreliable. The aim of our study was to evaluate the reliability of imageless navigation in acetabular positioning employing data acquisition in the supine position and surgery in the lateral position (‘flip technique’). We report 24 patients affected by primary osteoarthritis undergoing THA in which implants were placed with a conventional free-hand technique using the acetabular transverse ligament for cup orientation. For imageless navigation we used Orthopilot-Aesculap software. All patients had a postoperative computed tomography (CT) scan at three months, using previously validated dedicated software for cup orientation. Data collected using navigation software were compared with CT measurements. The mean acetabular inclination and anteversion recorded intra-operatively using navigation software were respectively 41°5’ (SD: 9.61) and 9°5’ (SD: 4.01) respectively. The mean inclination and anteversion calculated post-operatively by the CT based image software were 44°2’ (SD 5.83) and 14°4’ (SD 6.42) respectively. There was a statistically significant difference between the anteversion values (p=0.04). Therefore, the acquisition of parameters in the supine position with surgery performed in the lateral decubitus position creates unreliable data concerning cup anteversion using an imageless navigation system, and therefore the ‘flip technique’ cannot be recommended.

Biomechanical evaluation of six femurgraft-tibia complexes in ACL reconstruction

Soft tissue graft-tibial tunnel fixation is considered the weak point in reconstruction of the anterior cruciate ligament (ACL). We hypothesized that the biomechanical properties of fixation devices used in ACL reconstruction can be better evaluated by testing complete constructs (femoral tunnel fixation-graft-tibial tunnel fixation). Porcine knees were reconstructed with bovine digital extensor tendons using 6 different commercially available fixation device combinations, and biomechanically tested with cyclic loads (1000 cycles, 0–150 N, 0.5 Hz) and until failure (crosshead speed, 250 mm/min). The device combinations tested (in groups of 6) were EndoButton CL-BioRCI, Swing Bridge-Evolgate, Rifidfix-Intrafix, Bone Mulch- Washerlock, Transfix-Retroscrew, and Transfix-Deltascrew. Ultimate failure load, stiffness, slippage at cycles 1, 100, 500 and 1000 and mode of failure were evaluated. The statistical differences between pairs of groups were assessed with Student’s unpaired t test. The ultimate failure load of complexes made with the Swing Bridge- Evolgate was significantly higher than any other device (968 N; p<0.05), while that of devices made with Transfix-Retrofix was significantly lower than the others (483 N, p<0.05). The stiffness of Swing Bridge-Evolgate complexes was significantly higher than the others (270 N/mm, p<0.05). Regarding mode of failure, Rigidfix-Intrafix complexes showed a failure of the femoral fixation in all specimens. All failures of the other specimens occurred at the tibial side, except one specimen in the EndoButton CL-BioRCI group. Many commercially available tibial fixation devices showed biomechanically appreciable properties, sometimes better than femoral devices.