S. Parratte

Is knee function better with contemporary modular bicompartmental arthroplasty compared to total knee arthroplasty? Short-term outcomes of a prospective matched study including 68 cases

BACKGROUNDnBicompartmental knee arthroplasty (BKA) was developed to treat medial tibiofemoral and patellofemoral osteoarthritis while preserving the anterior cruciate ligament to optimise knee kinematics. Our objective here was to compare the probability of achieving forgotten knee status and the functional outcomes at least two years after BKA versus total knee arthroplasty (TKA). We hypothesised that contemporary modular BKA produced better functional outcomes than TKA after at least two years, for patients with similar pre-operative osteoarthritic lesions.nnnMATERIAL AND METHODSnWe conducted a two-centre prospective controlled study of 34consecutive patients who underwent BKA between January 2008 and January 2011. Each patient was matched on age, gender, body mass index, preoperative range of knee flexion, centre, and surgeon to a patient treated with TKA. An independent observer evaluated all 68 patients after six and 12months then once a year. Forgotten knee status was defined as a 100/100 value of the Forgotten Joint Score (FJS-12) and each of the five KOOS subscales. We also compared the two groups for knee range of motion, Knee Society Scores (KSSs), Timed Up-and-Go test (TUG), and UCLA Activity Score.nnnRESULTSnAt a mean follow-up of 3.8±1.7 years, the probability of forgotten knee status was significantly higher in the BKA group (odds ratio, 4.64; 95% confidence interval, 1.63-13.21; P=0.007, Chi(2) test). Mean post-operative extension was not significantly different between the groups, whereas mean range of knee flexion was significantly greater in the BKA group (130°±6° vs. 125°±8° after TKA; P=0.03). The BKA group had significantly higher mean values for the knee and function KSSs, TUG test, and UCLA score (P<0.04 for all four comparisons).nnnCONCLUSIONnAfter at least two years, contemporary unlinked BKA was associated with greater comfort during everyday activities (forgotten knee) and better functional outcomes, compared to TKA. These short-term results require validation in randomised trials with longer follow-ups.nnnLEVEL OF EVIDENCEnIII, case-control study.

Use of porous tantalum components in Paprosky two and three acetabular revision. A minimum five-year follow-up of fifty one hips

IntroductionRecent studies have reported short-term favourable results of tantalum-made components in acetabular revisions with bone loss. However, there is a lack of information regarding the mid to long-term results of such components.ObjectivesThe objective of this study was to analyse the outcome and survivorship of acetabular revision hip arthroplasty using tantalum components for loosening associated with bone loss at a minimum of five-year follow-up.MethodsWe retrospectively reviewed 51 consecutive patients (51 hips) who had an acetabular revision using porous tantalum components at a minimum follow-up of fivexa0years. The mean age was 64xa0years (range, 31–87). There were 27 males and 24 females, 47 right hips and four left hips. Twenty-five (49xa0%) included a femoral revision. According to Paprosky’s classification 18 hips were classified type 2A, 11 type 2B, ten type 2C, seven type 3A and five type 3B. No bone grafting was performed. Sixteen hips (31.3xa0%) required the use of additional tantalum-made augments stabilized by screws and cement at the cup-augment interface.ResultsAt a mean followup of 6.8xa0years (range, 5.1–10 years), the Harris hip score improved from 44 pre- operatively (range, 23–72) to 84 post-operatively (range, 33–98). The mean post-operative hip centre position in relation to the teardrop was 29xa0mm (range, 20—43xa0mm) horizontally and 21xa0mm (range, 8—36xa0mm) vertically. The mean acetabular inclination was 42° (range, 17–60°). Six hips (11.7xa0%) required a re-operation without component revision (two for chronic instability, one ossification removal, one haematoma, one deep infection and one periprosthetic femoral fracture). One patient required a cup re-revision for septic loosening. No aseptic loosening occurred. At last followup the radiological analysis showed one evolutive osteolysis and one screw breakage. The global survivorship was 92.3xa0% at 64xa0months. If only aseptic loosening was defined as the end-point the survivorship was 100xa0% at 64xa0months.ConclusionsWhen facing an acetabular revision with severe bone loss, tantalum-made components can provide a stable fixation. This study at a minimum five-year follow-up compares favourably with other reconstruction techniques, but longer follow-up is still required.

Relation between lower extremity alignment and proximal femur anatomy. Parameters during total hip arthroplasty.

BACKGROUNDnLower extremity alignment correlates with native femoral offset. Eventual impact of the change in femoral offset induced by total hip arthroplasty (THA) on lower extremity alignment has not been documented.nnnHYPOTHESISnTHA significantly changes lower extremity alignment, and the change correlates with the change in femoral offset.nnnMATERIALS AND METHODSnWe conducted a prospective study of 200 patients with primary hip osteoarthritis or avascular femoral head necrosis who underwent cementless THA. Pre-operative computed-tomography templating was performed and the femoral component was then custom-manufactured to replicate the native femoral anatomy. Mean age was 58 years (range, 28-83 years). Before and at least two years after THA, two observers who were not involved in the surgical procedures used standing antero-posterior long-leg radiographs to determine the mechanical axis of the lower-limb (hip-knee-ankle [HKA] angle), femoral offset, neck-shaft angle (NSA), and lower-limb length discrepancy (LLLD).nnnRESULTSnMean values pre-operatively and at last follow-up were as follows: HKA angle, 179.2° ± 3.9° (range, 170.5° to 190.5°) and 177.7° ± 3.5°(range, 173° to 187°); LLLD, -0.7 mm (range, -30 mm to +25 mm) and +5.1 mm (range, -7 mm to +21 mm); NSA, 134° ± 7.5° (range, 100° to 124°) and 135° ± 4.2° (range, 124° to 146°); and femoral offset, 42 ± 7.8 mm (range, 24 mm to 68 mm) and 49 ± 7.5 mm (range, 33 mm to 70 mm). Although THA significantly altered lower-limb alignment, univariate and multivariate analyses showed no significant association between the change in HKA angle and the change in femoral offset.nnnDISCUSSIONnLower-limb alignment was significantly affected by THA, although the HKA angle changes were small. The small impact of THA on HKA angle values may be ascribable to efforts aimed at replicating the native femoral offset during arthroplasty, as well as to the limited sample size and to potential measurement errors related to the small size of the changes. Our results suggest that, provided careful attention is directed to replicating the native femoral offset, THA in patients with limited pre-operative anatomical abnormalities may have no major impact on the biomechanical parameters of the ipsilateral knee.nnnLEVEL OF EVIDENCEnLevel III, prospective diagnostic study.

Titanium-titanium modular neck for primary THA. Result of a prospective series of 170 cemented THA with a minimum follow-up of 5 years

BACKGROUNDnAlthough they have been in use since the end of the 1980s, modular titanium neck components are associated with a risk of wear or fracture, and their safety has recently become a subject of debate and has never been evaluated in a consecutive series of patients. The goal of this study was to evaluate: revision-free survival of these implants after a minimum follow-up of 5 years; clinical and radiographic results; and the potential complications associated with the use of modular titanium neck components.nnnHYPOTHESISnThe use of titanium modular neck on cemented titanium THA is safe at a minimum follow-up of 5 years.nnnPATIENTS AND METHODSnBetween January 2006 and December 2008, we prospectively followed 170 patients (170 hips) who underwent primary anatomical THA with a modular cemented titanium stem design implant. The indications were unilateral THA for primary (n=160) or secondary (n=10) hip osteoarthritis (aseptic osteonecrosis of the femoral head or hip dysplasia). Mean age of patients was 75.4±5.8 years old (52-85), and mean BMI was 26.1±4.5 kg/m(2) (16.6-42.1). Patients were operated on by a modified Watson-Jones anterolateral approach based on preoperative 2D planning. All patients underwent annual clinical and radiological follow-up by an independent observer.nnnRESULTSnAt a mean follow-up of 71±8 months (60-84), 5 patients died and 7 were lost to follow-up. There was no revision of THA after a maximum follow-up of 84 months. The Harris score improved significantly from 50.4±11.3 (0-76) preoperatively to 84.5±15.2 (14-100) at the final follow-up. There was no difference in postoperative femoral offset or the position of the center of rotation compared to the opposite side. On the other hand, the neck-shaft angle (NSA) and limb length were corrected (2±5° [-11 to +14°] and 2.16±3.6 mm [-7.4 to +12.7 mm]) respectively. Fifteen patients (9%) had limb length discrepancies of more than 5 mm and 4 patients (2%) of more than 10 mm. There were no complications due to the modular implant design.nnnDISCUSSIONnOur study suggests that the use of cemented titanium implants with a modular titanium stem is safe at a follow-up of 5 years. The modular design does not prevent limb length discrepancies but restores femoral offset.nnnLEVEL OF EVIDENCEnIV: prospective, non-comparative study.

Can three-dimensional patient-specific cutting guides be used to achieve optimal correction for high tibial osteotomy? Pilot study

INTRODUCTIONnTreatment of medial tibiofemoral osteoarthritis with a high-tibial osteotomy (HTO) is most effective when the optimal angular correction is achieved. However, conventional instrumentation is limited when multiplanar correction is needed.nnnHYPOTHESISnUse of patient-specific cutting guides (PSCGs) for HTO provides an accurate correction (difference<2°) relative to the preoperative planning.nnnMATERIALS AND METHODSnBetween Februaryxa02014 and Februaryxa02015, 10xa0patients (mean age: 46xa0years [range: 31-59]; gradexa01 or 2 osteoarthritis in Ahlbäcks classification) were included prospectively in this reliability and safety study. All patients were operated using the same medial opening-wedge osteotomy technique. Preoperative planning was based on long-leg radiographs and CT scans with 3D reconstruction. The PSGCs were used to align the osteotomy cut and position the screw holes for the plate. The desired correction was achieved in the three planes when the holes on the plate were aligned with the holes drilled based on the PSCG. Preoperatively, the mean HKA angle was 171.9° (range: 166-179°), the mean proximal tibial angle was 87° (86-88°) and the mean tibial slope was 7.8° (1-22°). The postoperative correction was compared to the planned correction using 3D CT scan transformations. Intraoperative and postoperative complications were assessed at a minimum follow-up of 1xa0year.nnnRESULTSnThe procedure was successfully carried out in all patients with the PSCGs. On postoperative long-leg radiographs, the mean HKA was 182.3° (180-185°); on the CT scan, the mean tibial mechanical angle was 94° (90-98°) and the mean tibial slope was 7.1° (4-11°). In 19 out of 20xa0postoperative HKA and slope measurements, the difference between the planned and achieved correction was <2° based on the 3D analysis of the three planes in space; in the other case, the slope was 13° instead of the planned 10°. The intra-class correlation coefficients between the postoperative and planned parameters were 0.98 [0.92-0.99] for the HKA and 0.96 [0.79-0.99] for the tibial slope. There were no surgical site infections; one patient had a postoperative hematoma that resolved spontaneously.nnnDISCUSSIONnThe results of this study showed that use of PSCGs in HTO procedures helps to achieve optimal correction in a safe and reliable manner.nnnLEVEL OF EVIDENCEnIV - Prospective cohort study.

Unicompartmental Knee Arthroplasty in Medial Osteoarthritis: The Basics

Unicompartmental knee arthroplasty (UKA) is designed for patients presenting isolated degenerative unicompartmental medial or lateral femorotibial wear or wear related to aseptic osteonecrosis of the femoral condyle, most frequently medial.

Influence of treatment modality on morbidity and mortality in periprosthetic femoral fracture. A comparative study of 71 fractures treated by internal fixation or femoral implant revision

INTRODUCTIONnThe incidence of periprosthetic femoral fracture is constantly increasing, with high associated morbidity and mortality. Surgical treatment is guided by the Vancouver classification, but the influence of type of treatment on morbidity and mortality has been little analyzed. The theoretical advantage of implant revision over internal fixation is that it should allow earlier weight-bearing, although the impact of this on morbidity and mortality and autonomy has not been demonstrated. We conducted a case-control study, to assess the influence of type of treatment (implant revision or internal fixation) (1) on mobility and autonomy and (2) on morbidity and mortality.nnnHYPOTHESISnThe study hypothesis was that clinical results and morbidity and mortality do not differ between these two types of treatment.nnnMETHODSnA retrospective study included 70 patients with a total of 71 femoral periprosthetic fractures treated between 2007 and 2014. Two treatment groups, comparable for mean age, gender and ASA and Parker scores, were studied. Mean age was 78±13.5years (range, 23-95years). Thirty-six fractures (50.7%) were treated by implant revision via a posterolateral approach, using a revision stem with (n=11) or without cement (n=25) (REVISION group); immediate postoperative weight-bearing was authorized. Thirty-five fractures (49.3%) were treated by open reduction and internal fixation, using a locking plate (ORIF group); weight-bearing was authorized only in the third month. Mean follow-up was 43±27months (range, 0.75-107months).nnnRESULTSnAutonomy on Parker score was reduced by 2 points at 1years follow-up. Mean preoperative scores were 7.32±1.79 (range, 3-9) and 7.43±1.79 (range, 4-9) in the REVISION and ORIF group, respectively, (p=0.8), falling to 5.06±2.6 (range, 0-9) and 4.5±2.01 (range, 0-9) respectively at follow-up (p=0.349). Sixteen patients in the REVISION group versus 13 in the ORIF group had made adaptations in their home or changed place of residence (p=0.2). At last follow-up, 18 patients (28.6%) had died: 12 (37.5%) in the ORIF and 6 (19.3%) in the REVISION group (p<0.05). Survival with death as endpoint at a mean 3.5years was 88±11% in the REVISION group versus 51±11% in the ORIF group (p=0.02). Three implant replacements were performed in each group (p=0.83). Twelve medical or surgical complications occurred in the ORIF group (37.5%) and 11 in the REVISION group (34%) (p=0.9).nnnCONCLUSIONnImplant revision for periprosthetic femoral fracture showed significantly lower overall mortality than internal fixation, without difference in terms of treatment failure or complications requiring revision surgery.nnnLEVEL OF EVIDENCEnLevel III, case-control study.