Henri Robert

A new knee arthrometer, the GNRB ® : Experience in ACL complete and partial tears

INTRODUCTIONnClinical diagnosis of anterior cruciate ligament (ACL) tears (Lachman test and Pivot shift test in valgus and internal rotation) is reliable in case of complete ACL tear but reveals elusive in case of partial tears. Quantitative assessment of anterior tibial translation proves to be imprecise, subjective and poorly reproducible especially with the KT-1000 arthrometer. We developed the GNRB, an alternative original anterior knee laxity measurement device. The lower limb is placed in a rigid support with the knee at 0 degrees of rotation, the restraining power being recorded. A 0-250 N thrust force is transmitted by a jack to the upper segment of the calf. This force is only applied in the absence of hamstring muscles contraction. Displacement of the anterior tibial tubercle is recorded using a sensor with a 0.1mm precision.nnnHYPOTHESISnWe hypothesize that this knee laxity measurement device is more reliable and reproducible than other currently available arthrometers.nnnMATERIAL AND METHODSnDuring a first validation study, the GNRB was compared to the KT-1000 arthrometer, in 20 pairs of healthy knees, measurements being performed by two investigators. Variance analyses were carried out at 134 N. In a second clinical study, 21 complete ACL tears (the notch is devoid of ACL) and 24 partial ACL tears (anterior or posterior bundle tear and cicatricial ACL remnant in continuity) were tested with these arthrometers to exact a differential laxity threshold value between both knees at 250 N. Statistical analysis was subsequently performed using variance and ROC curves analysis.nnnRESULTSnThe GNRB arthrometer reveals to be significantly more reproducible than the KT-1000, irrespectively of the testers experience level. Moreover, unlike the KT-1000, the achieved measurement is independent from the uninvolved side. Reproducibility of laximetry proves to be significantly better with the GNRB than with the KT-1000, wherever the examiners experience stands and whatever the evaluated side condition could be. When differential laxity threshold value was 3mm in complete ACL tears, sensitivity was 70% and specificity 99% at 134 N. Using a 1.5mm threshold value in ACL partial tears, the arthrometer sensitivity was 80% and specificity was 87% at 134 N.nnnDISCUSSIONnReproducibility of laximetry was significantly better with the GNRB than the KT-1000 device, wherever the examiners experience stands and whatever the evaluated side-condition could be. The GNRB reports various supplementary advantages compared with other available laximeters. Good control of the investigated limb position in rotation, recording of translation in the absence of hamstring muscles contraction and in direct comparison with the KT-1000: reproducibility, constant pressure, arthrometry improved accuracy and automated measurements recording. The GNRB might be used for diagnosis of partial and complete ACL tears and during follow-up of reconstructed or not ACL tears.nnnLEVEL OF EVIDENCEntype II. Prospective comparative study.

The Comparative Role of the Anterior Cruciate Ligament and Anterolateral Structures in Controlling Passive Internal Rotation of the Knee: A Biomechanical Study

PURPOSEnTo determine the respective functions of the anterior cruciate ligament (ACL) and the anterolateral structures (ALSs) in controlling the tibias passive internal rotation (IR) with respect to the femur, under uniaxial rotation.nnnMETHODSnTo test the function of the ACL and the anterolateral ligament (ALL) in IR, we designed a sequential transection study of the ACL and the anterolateral structures (including the ALL) in 24 cadaveric knees divided in 2 groups. Two sequences were conducted successively: group 1 (12 knees) in which the ACL was sectioned first followed by the ALS, and group 2 (12 knees) with reversed transections. Each knee, in neutral rotation position and at flexion angle of 30°, was subjected to a 5 Nm torsion torque of IR. IR was measured using a rotatory laximeter, the Rotam with a gyroscopes measurement accuracy of 0.1°. Laxities were compared using paired t test within each group and using t test between groups. Fisher exact test was used to compare proportions.nnnRESULTSnIn group 1, IR increased from 22.1° ± 10.6° to 25.7° ± 10.9° after ACL transection then to 28.1° ± 10.5° after we sectioned the ALS. In group 2, IR increased from 22.5° ± 8.9° to 25.2° ± 8.4° after sectioning the ALS, then to 29.1° ± 8.8° after we sectioned the ACL. Total postsectioning increase in IR was 6.4° ± 2° in group 1, and 6.55° ± 0.9° in group 2. The IR increase after each stage of transection and final IR were statistically significant (P < .001).nnnCONCLUSIONSnIn a pure rotational cadaveric test model, the ACL and the ALS contribute to resistance to passive IR of the knee.nnnCLINICAL RELEVANCEnIn some specific clinical cases, peripheral lesions may be considered, and injuries to these structures may need to be addressed to improve results controlling postoperative IR.

Do graft diameter or patient age influence the results of ACL reconstruction

AbstractPurposenHamstring tendons are commonly used as a graft source for ACL reconstruction. This study seeks to determine whether either the diameter of the tendon graft or the age of the patient influences the outcome of the ACL reconstruction when measured using a standard, previously validated laxity measurement device.MethodsnThis is a retrospective study of 88 patients who underwent ACL reconstruction with a short, quadrupled tendon technique, using the semitendinosusxa0±xa0gracilis tendons. Patients included in this study were sequential, unilateral, complete ACL ruptures. The patients were followed for a minimum of 1xa0year postoperatively, with a mean follow-up of 26xa0months. Patients were divided into three groups according to the diameter (Ø) of the graft: group 1 (32 patients): 8xa0mmxa0≤xa0Øxa0≤xa09xa0mm; group 2 (28 patients): 9xa0mmxa0<xa0Øxa0≤xa010xa0mm; and group 3 (28 patients): Øxa0>xa010xa0mm. Three groups with differential laxity at 134xa0N (Δ134xa0=xa0healthy side vs. operated side) measured with the laximeter GNRB® were compared. The risk of residual laxity (OR) between the three groups taking age, gender, BMI and meniscus status into account was calculated. A side-to-side laxity >3xa0mm was considered as a residual laxity.ResultsThe mean patient age at the time of reconstruction was 29.4xa0years. The three groups were comparable. Postoperative Δ134 was 1.50xa0±xa01.3, 1.59xa0±xa01.5 and 2xa0±xa01.7xa0mm for groups 1 through 3, respectively. Δ134xa0>xa03xa0mm was observed in three patients in group 1, four patients in group 2 and nine patients in group 3. As compared to group 1, OR was 1.46 (95xa0% CI 0.35–6.05) and 3.31 (95xa0% CI 0.89–12.34) in groups 2 and 3, respectively. Adjustment for age, gender, BMI and meniscus did not change the estimates [OR 1.44 (95xa0% CI 0.34–6.16) and 3.92 (95xa0% CI 1–15.37)] in groups 2 and 3, respectively. Patients younger than 20 had a significantly higher average postoperative laximetry (2.4xa0±xa01.5xa0mm) compared to those aged 20xa0years and over (1.5xa0±xa01.5xa0mm) (pxa0=xa00.03), regardless of the diameter of the graft.ConclusionThe diameter of the graft between 8 and 10xa0mm does not affect the laximetric results of an ACL reconstruction. Therefore, there does not appear to be a benefit to harvesting and adding further tissue to increase the diameter of the graft above 10xa0mm. Patients younger than 20 represent a population at risk of graft elongation. In these patients at risk, postoperative management needs to be modified (delayed weight bearing, articulated splinting, slower rehabilitation) in the first months.Level of evidenceRetrospective case series, Level IV.

Treatment of large deep osteochondritis lesions of the knee by autologous matrix-induced chondrogenesis (AMIC): Preliminary results in 13 patients

BACKGROUNDnOsteochondral defects due to advanced osteochondritis of the knee eventually cause osteoarthritis. Autologous matrix-induced chondrogenesis (AMIC) may hold potential for overcoming the treatment challenges raised by defects larger than 2cm2. The primary objective of this study was to assess medium-term functional outcomes of AMIC. The secondary objective was to confirm the absence of adverse events.nnnHYPOTHESISnAMIC significantly improves knee function in patients with osteochondritis responsible for osteochondral defects grade III or IV in the International Cartilage Repair Society (ICRS) classification.nnnMATERIAL AND METHODSnA total of 13 consecutive patients managed using AMIC between September 2011 and November 2016 were included in a prospective, single-centre, single-surgeon study. There were 8 males and 5 females with a mean age of 29 years (range, 15-51 years). Among them, 9 had had previous surgery. The ICRS grade was IV in 12 patients and III in 1 patient. The defects had a mean surface area of 3.7cm2 (range, 2.2-6.9cm2) and mean depth of 0.5mm (range, 0.4-0.8). In each patient, knee function was assessed by an independent examiner based on validated instruments (Knee injury and Osteoarthritis Outcome Score [KOOS], subjective International Knee Documentation Committee [IKDC] score, and visual analogue scale [VAS] pain score).nnnRESULTSnAfter a median follow-up of 24 months (range, 12-42 months; minimum, 1 year), 11 patients had significant improvements, with mean increases in the IKDC score and KOOS of 27 and 28 points, respectively. The scores remained stable after the first year. Of the 2 patients with poorer outcomes, 1 had a history of multiple surgical procedures and the other was a 51-year-old female with a defect surface area of 6.9cm2. No post-operative complications were recorded.nnnCONCLUSIONnAMIC is a reliable single-stage method that is both reproducible and widely available. AMIC significantly improves knee function scores in patients with large osteochondral defects due to advanced osteochondritis of the knee.nnnLEVEL OF EVIDENCEnIV, prospective cohort study.

Ambulatory unicompartmental knee arthroplasty: Short outcome of 50 first cases

INTRODUCTIONnThe reduction in length of stay (LOS) in orthopedic surgery has been steady for several years. For the past 3 or 4 years in France, the trend toward outpatient surgery has been growing upwards, as it is a goal for hospital administration.nnnMATERIALS AND METHODSnThis is a prospective, continuous, mono-centric, single operator study on 56 UKAs. Included were all UKAs carried out between January 2014 and December 2015, meeting the following criteria: voluntary patients, supportive family environment, absence of comorbidity (oral anticoagulants, diabetes, obesity), ASA score≤3. Preoperatively, patients received: Dexamethasone 2mg/10kg, Tranexamic acid 2g, Cefazolin 2g IV. All patients were operated on under general anesthesia with the same technique: Alpina® (Zimmer-Biomet) uni-prosthesis without tourniquet. The arthrotomy was closed after a capsular injection of a solution of 150mg Ropivacaine+30mg Bi-Profenid®. Patient discharge on the same day evening was authorized by both surgeon and anesthesiologist. Three criteria were quantified: number of patients seen before the date of the first consultation for the removal of stitches (around day 12), Visual Pain Scale (10 points scale) on the first 12 days, and the level of satisfaction at the one-month postoperative visit.nnnRESULTSnSix patients (11%) were not included in the ambulatory program during the initial consultation. Three patients were not able to be discharged on the same day evening due to nausea and therefore remained hospitalized for one night. Eighteen patients (38%) were reviewed before D10: 13 patients were reviewed between D1 and D4 for bleeding through the dressing and 5 for pain not controlled by level 1 and 2 analgesics. The Visual Pain Scale (VPS) reached level 6±2 by the 2nd day and then dropped to 1±1 by the 12th day. At 1 month, 85% of the patients were satisfied or very satisfied with their care. There were no general or localized complications.nnnDISCUSSIONnAmbulatory UKA surgery is possible for most patients. The inclusion rate for ambulatory UKA was 88% for Berger RA in 2010, therefore very close to this study rate of 89%. Ambulatory care is not only a change in surgical and anesthetic practice but a totally new management process involving all medical and non-medical actors. Ambulatory UKA surgery is feasible and safe for most patients.nnnLEVEL OF EVIDENCEnIV, retrospective cohort study.