Minimally invasive surgery of femoral periprosthetic fractures increases the rate of consolidation and decreases time to bone healing without a higher rate of complications.

BACKGROUND: Knee periprosthetic femoral fractures (KPPFF) are becoming more frequent due to the increasing number of arthroplasties and the aging population, for whom maintaining autonomy and function remains a challenge. The use of locking plates has improved functional results and promoted the development of "minimally invasive" surgical (MIS) approaches. Despite the availability of literature comparing between different types of osteosynthesis for KPPFF, there is a paucity of information available on the complications of osteosynthesis using locking plates, depending on the approach. We therefore carried out a retrospective multicenter study (nine centers: Dijon, Grenoble, Lille, Marseille, Nice, Paris, Saint-Étienne, Strasbourg, Colmar) as part of a Symposium of the French Society of Orthopedic Surgery and Traumatology (SOFCOT). Following osteosynthesis of KPPFF by locking plates carried out by a standard approach or by a minimally invasive approach (MIS), the objectives were: (1) to compare the complications, (2) to evaluate whether the radiological and clinical results (rate and time of consolidation, resumption of weight bearing, lack of reduction, postoperative autonomy) were comparable in the two groups. HYPOTHESIS: The hypothesis was that performing an MIS approach in these indications does not confer more complications than a standard approach, and rather, the MIS approach offers better functional and radiological results. MATERIAL AND METHOD: Five hundred and seventy-three patients presented with KPPFF over the periods studied (retrospective series from January 2012 to December 2016, then prospective series from January to December 2019). After applying the inclusion criteria (KPPFF by locking plate) and exclusion criteria (tumor context, infectious, intraoperative fractures, fractures on loose prostheses, other osteosynthesis methods, treatment by prosthetic revision, patients under the age of 18, follow-up less than 1-year, incomplete files), a global series of 306 patients was retained. Two groups were created according to the approach performed: a standard approach group (S, n=228) and a minimally invasive approach group (MIS, n=78). The demographic data of the population were recorded, as was the criteria for autonomy (Parker score, place of living). Postoperative complications were sought (infection, mechanical complication, surgical revision). Finally, the radiological and clinical results were evaluated (rate of, and time to consolidation, resumption of weight bearing, lack of reduction, postoperative autonomy). RESULTS: The comparison of the two subgroups, S and MIS, found complication rates are comparable in the two groups in terms of infections [S group: n=18 (7.9%), MIS group: n=2 (2.6%)], mechanical complications [S: n=23 (10.1%), MIS: n=2 (2.6%)], and surgical revision [S: n=33 (14.5%), MIS: n=7 (8.9%)], and a lack of difference in postoperative autonomy [Parker; S group: 4.7±2.4 (0-9) vs. MIS group: 5±2, 7 (0-9)]. On the other hand, the time to return to weight bearing was shorter in the MIS group [4.3±3.5weeks (0-12) versus 10.1±10.1weeks (0-110), p<0.001]. The rate of nonunion was lower in the MIS group [n=1 vs. n=20, i.e. 1.7% vs. 11.1% (p=0.031)] and the time to consolidation was shorter [7.5±4.3weeks (6-30) versus 15.2±9.4weeks (5-78) (p<0.001)]. CONCLUSION: Performing an MIS approach in the management of KPPFF by locking plate osteosynthesis does not cause any more complications than a standard approach. In addition, higher consolidation rates can be obtained in shorter periods of time. This study suggests that it proposing osteosynthesis using the MIS approach as a primary surgery is a reasonable choice when treatment using locking plates is chosen for a KPPFF, subject to technical expertise. LEVEL OF EVIDENCE: III; observational study.

Revision total knee arthroplasty with periprosthetic distal femoral fracture.

Treatment strategies for periprosthetic distal femoral fracture depend on the type of fracture, level with respect to the prosthesis, and prosthesis fixation. The usual treatment is internal fixation by nail or locking plate. This can be more difficult when the fracture is close to the joint, is destabilizing the prosthesis or is associated with reduced bone stock, and implant exchange should be considered, depending on the patient's health status. The aim is to obtain the fastest possible recovery while limiting complications and minimizing surgery time for often frail and elderly patients. The present study details the implant revision technique in periprosthetic distal femoral fracture, which requires experience in traumatology and prosthetic revision and material adapted to the situation. LEVEL OF EVIDENCE: V, expert opinion.

Management of periprosthetic femoral fractures following total knee arthroplasties using locking plates or intramedullary nailing. Comparative study of 567 cases.

INTRODUCTION: Proximal femur fractures in elderly patients pose a common problem that requires surgical management. The main objective of this study was to compare the results of treatment by locked plate (LP) and by anterograde (AIN) or retrograde (RIN) intramedullary nailing. The secondary objective was to analyze the complications related to each group. The hypothesis of this study was that the radiological and clinical results of each group were comparable. MATERIALS AND METHODS: The data of 438 patients from 8 centers were studied retrospectively with 365 LP and 69 cases of intramedullary nailing (49 AIN and 20 RIN). The groups were comparable in terms of mean age (75±2years), mean preoperative Parker score (5.3±0.5) and mean KOOS score (74±2). Most patients lived at home before their fracture [n=375 (86%)]. At follow-up, the joint range of motion, the KOOS and Parker scores, living premises, the time required to regain full weight-bearing, the time required for consolidation as well as the reduction alignment: frontal, sagittal, horizontal. RESULTS: The average follow-up was: 79±2weeks (65 to 82). The functional and radiological results were comparable, although nailing allowed a faster return to weight-bearing (1±2weeks for nailing versus 7±2weeks for LP, p=0.048) and a better postoperative Parker score (5.5±0.5 for nailing versus 4.7±0.2 for LP, p=0.045). Rotational malalignment in femoral nailing was often in the direction of internal rotation, compared to the LP (p=0.045). Complications were comparable with the exception of mortality, which was more frequent for LP [22.5% in the LP group versus 13% in the nailing group (p=0.045)]. Complications were categorized as: mechanical complications 6.8% of LP, 5.7% of nailing (p>0.05), infections [11% of LP, 5.8% of nailing (p>0.05)], surgical revisions [2% of LP, 10% of nailing (p>0.05)]. DISCUSSION AND CONCLUSION: The hypothesis was refuted. These results show that nailing conferred a faster recovery of weight-bearing, a better Parker score, and is associated with a lower mortality rate. The morbidity rate is comparable between the two techniques. Indeed, when the indication for osteosynthesis by LP or by nailing is made, and both choices are technically justifiable, it would be prudent to favor the technique, which carries the least risk, which in this case is nailing. This conclusion must, however, be taken in to consideration with regard to the reduced number of nailing. A larger series of nailing, particularly retrograde, would be necessary to be able to confirm this last difference between the 2 groups. LEVEL OF EVIDENCE: IV; comparative retrospective study.

Rehabilitation protocol after suturing the medial meniscus of a stable knee, a retrospective series of the Francophone Arthroscopy Society.

INTRODUCTION: Surgical meniscal lesions are common and 80% of cases involve the medial meniscus of a stable knee. There is a lack of consensus regarding postoperative rehabilitation protocols and a wide variation between restrictive and accelerated rehabilitation protocols exists. The main objective of this study was to report the functional results and the failure rate of the various rehabilitation protocols of the retrospective series of the French Society of Arthroscopy (SFA) after suturing the medial meniscus of a stable knee, considering whether the tear is stable or unstable. HYPOTHESIS: Our hypothesis was that accelerated rehabilitation was not associated with an increased risk of failure. MATERIALS AND METHODS: This retrospective, multicenter study was conducted across 10 centers (6 private hospitals and 4 public hospitals) including all patients tested for a medial meniscus suture in a stable knee between January 1, 2005 and November 31, 2017 for a minimum follow-up of 5years. Demographic, imaging, suturing, rehabilitation protocol, and functional TEGNER and KOOS scores were collected. Failure was defined as performing a secondary meniscectomy. RESULTS: Three hundred and sixty-seven patients were analyzed with an average follow-up of 82months. Immediate weight bearing was allowed in 85% of cases, the wearing of a brace was present in almost 74% of cases and flexion was limited in 97% of cases. Inter-group comparisons found a higher suture failure rate in the group with immediate weight bearing (35.6% vs. 20%, p=0.011) and in the group with a brace (36.9% vs. 22.4%, p<0.001). There was no difference in the 90° flexion group. The TEGNER score was higher in the non-weight bearing group (6.5 vs. 5.4, p=0.028) and the KOOS QOL score was higher in the group without a brace (82.2 vs. 66.8, p=0.025). According to a multivariate analysis, immediate weight bearing (OR=3.6, [1.62; 7.98], p=0.0016) and wearing a brace (OR=2.83, [1.54; 5.02], p<0.001) were associated with a higher failure rate. In the group of stable lesions, the use of a brace (OR=3.73, [1.62; 8.56], p=0.0019) was associated with a higher failure rate. CONCLUSION: No consensus regarding rehabilitation protocols has been established to date and the results of this retrospective series of the SFA affirm the great variability of practices at a national level. Although accelerated rehabilitation protocols are presently favored, the resumption of immediate full weight bearing should be considered with caution, being associated with a higher risk of failure in this series. Deferring weight bearing for 1 month can be considered in the event of a large tear or in the event of damage to the circumferential fibers. Wearing a brace does not seem to have any influence, while limited flexion achieved a consensus. LEVEL OF EVIDENCE: IV, retrospective study.

Experimental study of risk of medial hinge fracture during distal femoral varus osteotomy.

INTRODUCTION: Lateral opening wedge distal femoral osteotomy (LOWDFO) is indicated for isolated lateral osteoarthritis in the valgus morphotype. Medial hinge fracture is a factor for poor prognosis. The present study had two aims: (1) to assess the impact of a temporary K-wire on hinge fracture risk; and (2) to assess the impact of LOWDFO opening speed. HYPOTHESIS: The main study hypothesis was that a temporary hinge K-wire reduces hinge fracture risk. The second hypothesis was that faster opening speed increases fracture risk. MATERIAL AND METHOD: Twenty femurs were produced by 3D printing from a CT database, reproducing LOWDFO anatomy. The ABS® polymer showed the same breaking-point behavior as human bone. Ten specimens were included in the "K-wire" group (KW+) and 10 in the "No K-wire" group (KW-). To determine high and low speed, a motion-capture glove was used by 2 operators, providing 3D modeling of the surgeon's hand. High speed was defined as 152mm/min and low speed as 38mm/min. The KW+ and KW- groups were subdivided into high- and low-speed subgroups (HS, LS) of 5 each. Compression tests were conducted using an Instron® mechanical test machine up to hinge fracture. The main endpoint was maximum breaking-point force (N); the secondary endpoints were maximum displacement (mm) and maximum speed (min) at breaking point. RESULTS: The K-wire significantly increased maximum breaking-point force (LS, 143.08N vs. 93.71N, p<0.01; and HS, 186.98N vs. 95.22N, p<0.01), but not maximum displacement (LS, 26.17mm vs. 24.11mm, p=0.31; and HS 26.18mm vs. 23.66mm, p=0.14) or maximum time (LS, 27.07s vs. 24.94s, p=0.31; and HS, 5.24s vs. 4.73s, p=0.14). Speed did not affect maximum force (KW+, 143.08N vs. 186.98N, p=0.06; and KW-, 93.71N vs. 95.22N, p=0.42) or maximum displacement (KW+, 26.17mm vs. 26.18mm, p=1; and KW-, 24.11mm vs. 23.66mm, p=0.69). Only maximum time was greater at low speed (KW+, 27.07s vs. 5.24s, p>0.01; and KW-, 24.94s vs. 4.73s, p<0.01), which is obvious for constant distance. DISCUSSION: The first study hypothesis was confirmed, with significantly lower hinge fracture risk with the K-wire, independently of opening speed. The second hypothesis was not confirmed. The study was performed under strict experimental conditions, unprecedented to our knowledge in the literature. However, complementary clinical studies are needed to confirm the present findings. LEVEL OF EVIDENCE: IV, experimental study.

Experimental investigation of the risk of lateral cortex fracture during valgus tibial osteotomy.

BACKGROUND: Valgus-producing medial opening-wedge proximal tibial osteotomies (V-MOW-PTO) are used to treat isolated medial-compartment knee osteoarthritis in patients with varus malalignment. A fracture of the lateral cortical hinge is a risk factor for poor outcomes. Implantation of a protective K-wire has been suggested to prevent this complication. The primary objective of this bench study was to assess the ability of a protective K-wire to prevent lateral cortical fractures. The secondary objective was to evaluate the influence of the opening speed on fracture risk during the osteotomy. HYPOTHESIS: The primary hypothesis was that a protective K-wire decreased the risk of hinge fracture. The secondary hypothesis was that this risk was greater when the opening speed was high. MATERIALS AND METHODS: We performed an experimental study of 20 simulated thermoplastic-polymer (ABS) tibias obtained by 3D printing to assess the effects of wedge-opening speed (high vs. low) and presence of a protective K-wire (yes vs. no). The opening rates were determined in a preliminary study of Sawbone® specimens opened using a distractor. The opening rate was measured using an accelerometer via a motion-capture glove. After assessing several high and low opening speeds, we selected 38mm/min and 152mm/min for the study. We divided the 20 ABS specimens into four groups of five each: high speed and K-wire, low speed and K-wire, high speed and no K-wire, and low speed and no K-wire. The force was applied using an Instron™ testing machine until construct failure. The primary outcome measure was the load at failure (N) and the secondary outcome measures were the displacement (mm) and maximum time to failure (s). RESULTS: At both speeds, values were significantly higher with vs. without a K-wire for load to failure (low: 253.3N vs. 175.5N, p<0.01; high: 262.2N vs. 154.1N, p<0.01), displacement (low: 11.1mm vs. 8.7mm, p<0.01; high: 11mm vs. 8.9mm; p=0.012), and maximal time to failure (low: 11.4 s vs. 8.9 s; p=0.012; high: 2.2 s vs. 1.8 s; p=0.011). Thus, the osteotomy opening speed seemed to have no influence on the risk of lateral cortex fracture. DISCUSSION: Our main hypothesis was confirmed but our secondary hypothesis was refuted: a protective K-wire significantly decreased the risk of hinge fracture, whereas the osteotomy opening speed had no influence. To our knowledge, this is the first published study assessing the potential influence of opening speed on risk of lateral cortex fracture. Our findings were obtained in the laboratory and should be evaluated in clinical practice. LEVEL OF EVIDENCE: IV, experimental study.

Comparison of five methods for locked-plate fixation of complex diaphyseal fractures.

BACKGROUND: Peri-prosthetic fractures (PPFs) are steadily rising in number due to population ageing and increased performance of joint replacement procedures. Although PPFs without implant loosening are usually managed by internal fixation, no consensus exists regarding the optimal construct. The primary objective of this study was to compare five constructs, and the secondary objective was to compare sub-groups of mono-cortical screw constructs, with the goal of identifying the method most appropriate for diaphyseal fracture fixation when prosthetic material is present within the intra-medullary canal. HYPOTHESIS: The primary hypothesis was that fixation using bi-cortical screws, i.e., the current reference standard, was superior over other fixation methods. The secondary hypothesis was that adding double cerclage to mono-cortical screw fixation provided the greatest mechanical strength. MATERIALS AND METHODS: Synthetic osteoporotic bone was used to compare five methods for locking-screw fixation of a femoral diaphyseal plate. One method involved bi-cortical screws and four methods mono-cortical screws, with no cerclage wire, a single cerclage wire on either side positioned near or at a distance from the fracture, and two cerclage wires on both sides of the fracture. A complex fracture was simulated by creating a 2-cm diaphyseal gap. Load-to-failure was determined by applying compression loading along the anatomical axis of the femur. RESULTS: Bi-cortical screw fixation provided greater mechanical strength than did three of the four mono-cortical screw constructs. The exception was the mono-cortical-screw and double-cerclage construct, for which no significant difference was found compared to bi-cortical screw fixation. Thus, mono-cortical screw fixation with double cerclage may be the best alternative when presence of an implant in the intra-medullary canal precludes bi-cortical screw fixation. CONCLUSION: The findings from this study have clear implications for clinical practice. The study hypotheses were partly confirmed. The absence of a significant difference between the reference-standard bi-cortical screw fixation method and mono-cortical screw fixation with double cerclage, combined with the results regarding the secondary objective, suggest that mono-cortical screws plus double cerclage deserve preference in patients with an intra-medullary implant. Clinical studies are needed to assess the results of this bench study. LEVEL OF EVIDENCE: IV, bench study.

Comparison of the functional outcomes after treatment of periprosthetic hip fractures with femoral stem loosening: Locking plate fixation with or without femoral stem revision.

INTRODUCTION: Periprosthetic fractures have become one of the main reasons for revision of total hip arthroplasty, with the treatment strategy guided by the Vancouver and SOFCOT classification systems. The main objective of this work was to compare the functional outcomes and mortality rate in patients who suffered a periprosthetic hip fracture with femoral stem loosening and who were treated either by internal fixation with locking plate only, or in combination with revision of the existing femoral stem with a cemented stem. The secondary objective was to compare the blood loss, procedure duration, length of hospital stay, living arrangements, time to weight bearing and major complications between these two treatment strategies. The starting hypothesis was that there is no difference in the functional outcomes between these two groups. MATERIALS AND METHODS: This was a single center, retrospective study of patients treated between 2013 and 2019. Thirty-six patients (54%) underwent femoral stem revision (FSR group) and 31 patients (46%) were treated by locking plate fixation only (ORIF group). In this population, 19 of the patients had been residing at a nursing home before the surgical treatment: 12 (33%) in the FSR group and 7 (23%) in the ORIF group (p=0.33). The mean preoperative Parker score was 7.03 (± 1.48) in the FSR group versus 5.19 (± 1.92) in the ORIF group. The functional outcomes at the final review were evaluated using the Parker score, HHS (Harris Hip score), WOMAC (Western Ontario and McMaster Arthritis Index) and Oxford score. Fracture healing was determined on radiographs centered over the hip joint with the entire femur visible on AP and lateral views. All patients were reviewed at a minimum of 1 year for clinical and radiological assessments. RESULTS: At a mean follow-up of 28 months [12-85], the Oxford score was 40.4 (± 10.6) in the FSR group versus 37.1 (± 13.5) in the ORIF group (p=0.34), WOMAC of 45.5 (± 26.9) versus 50.5 (± 32.4) (p=0.56), and HHS of 62.7 (± 25.5) versus 60.3 (± 28.6) (p=0.79). The Parker score at the final assessment was 5.14 (± 1.96) in the FSR group versus 4.64 (± 2.17) in the ORIF group (p=0.33). In the FSR group, 10 patients were at a nursing home (34%), 6 of whom were not there initially, versus 6 in the ORIF group (43%), 5 of whom were not there initially (p=0.59). The mean operating time was 152±41.4 minutes (minimum: 85; maximum: 254) in the FSR group versus 89.2 (± 44.1) minutes (minimum: 39; maximum: 280) in the ORIF group (p<0.001). Resumption of full weight bearing occurred at 6 weeks in 21 patients (58%) in the FSR group versus 14 patients (47%) in the ORIF group (p=0.023). There were 5 major complications (14%) in the FSR group versus 7 (23%) in the ORIF group (p=0.35). Among the reviewed patients, the union rate was 86% on the latest radiographs in the FSR group versus 78% in the ORIF group. DISCUSSION: There was no statistically significant difference between groups in the various functional scores, confirming our study hypothesis. Internal fixation with a locking plate appears to be an acceptable solution for treating periprosthetic hip fractures in which the femoral stem has loosened. LEVEL OF EVIDENCE: III, comparative retrospective study.

Accuracy of the correction achieved after a valgus high tibial osteotomy: Comparison of the Hernigou table and navigation.

INTRODUCTION: The outcome of a medial opening wedge valgus high tibial osteotomy indicated for the treatment of isolated medial tibiofemoral osteoarthritis depends mainly on the accuracy of the correction of the hip-knee-ankle angle (HKAA) and the mechanical medial proximal tibial angle (mMPTA). Most authors aim for a desired correction target between 2° and 4° of valgus. Several planning and surgical techniques have been described to achieve this target value that is specific to each surgeon. OBJECTIVE: The purpose of this study was to compare the accuracy of the correction achieved using either the Hernigou table (HT) planning method or a computer-assisted navigation system (CAS). It was hypothesized that no difference would be found between these 2 techniques. MATERIALS AND METHODS: This retrospective single-center study involved 43 knees: 21 in the HT group and 22 in the CAS group. Two surgeons (ME, JYJ), who were experts in 1 of the 2 planning methods performed these procedures, with a single surgeon assigned to each group. The correction was noted in the operative report and was considered to be the desired correction target. The surgical correction was calculated by comparing preoperative and immediate postoperative mMPTA measurements. The surgical accuracy, where a value close to 0 represented optimal accuracy, was defined as the absolute value of the difference between the correction target set by the surgeon and the surgical correction achieved. The median accuracy between the 2 groups was compared by a Mann-Whitney U test (significance level at 5%). The number of patients deviating from the target by>3° was analyzed with a Fisher exact test (significance level at 5%). Pre- and postoperative comparisons of the HKAA measurements could not be used because the measurement was not performed postoperatively for the CAS group. RESULTS: The median surgical accuracy on the mMPTA was 1.4° (0-4.1) for the HT group versus 1.9° (0.2-6.7) for the CAS group (p=0.85). Sixteen procedures (76%) were performed with an accuracy of<3° in the HT group versus 15 in the CAS group (68%) (p=0.73). DISCUSSION-CONCLUSION: The working hypothesis was confirmed: no differences were found between the HT and CAS groups regarding the surgical accuracy in achieving the corrections set in this series. We therefore demonstrated that HT was a highly accessible, simple and reliable technique for achieving the planned target. It can be used widely. LEVEL OF EVIDENCE: III; comparative retrospective series.

Patients with varus knee osteoarthritis undergoing high tibial osteotomy exhibit more femoral varus but similar tibial morphology compared to non-arthritic varus knees.

PURPOSE: The aim of this study was to compare alignment parameters between patients undergoing high tibial osteotomy (HTO) for knee osteoarthritis (OA) and non-arthritic controls. METHODS: Pre-operative computed tomography images from 194 patients undergoing HTO for medial knee OA and 118 non-arthritic controls were utilized. All patients had varus knee alignment (mean age: 57 ± 11 years; 45% female). The hip-knee-ankle (HKA) angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA) and non-weight-bearing joint line convergence angle (nwJLCA) were compared between "control group" and "HTO group". Femoral and tibial phenotypes were also assessed and compared between groups. Variables found on univariate analysis to be different between the groups were entered into a binary logistic regression model. RESULTS: The mean age was lower (Δ = 4 ± 6 years, p = 0.024), body mass index (BMI) was higher (Δ = 1.1 ± 2.8 kg/m2, p = 0.032) and there were more females (Δ = 14%, p = 0.020) in the HTO group. The HTO group had more overall varus (7° ± 4.7° vs 4.8° ± 1.3°, p < 0.001). There was a significant difference in the mean mLDFA between the two groups with the HTO group having more femoral varus (88.7 ± 3.2° vs 87.3 ± 1.8°, p < 0.001). MPTA was similar between the groups (p = 0.881). Age was found to be a strong determinant for femoral varus (p = 0.03). CONCLUSION: Patients undergoing HTO for medial knee OA have more femoral varus compared to non-arthritic controls while tibial morphology was similar. This will be an important consideration in pre-operating planning for realignment osteotomy in patients presenting with medial knee OA and warrants further investigation. LEVEL OF EVIDENCE: III, retrospective comparative study.

Global varus malalignment increase from double-leg to single-leg stance due to intra-articular changes.

PURPOSE: Preoperatively planned correction for tibial osteotomy surgery is usually based on weightbearing long-leg Xrays, while the surgery is performed in a supine non-weightbearing position. The purpose of this study was to assess the differences in lower limb alignment in three different weightbearing conditions: supine position, double-leg (DL) stance and single-sleg (SL) stance prior to performing a medial opening wedge high tibial osteotomy (MOWHTO) for varus malalignment. The hypothesis of this study was that progressive limb-loading would lead to an increased preoperative varus deformity. MATERIAL AND METHODS: This retrospective study included 89 patients (96 knees) with isolated medial knee osteoarthritis (Ahlbäck grade I or II) and significant metaphyseal tibial vara (> 6°). The differences between supine position, DL stance and SL stance were analysed for the hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), weight-bearing line ratio (WBL) and joint line convergence angle (JLCA). RESULTS: From a supine position to DL stance, the HKA angle slightly increased from 175.5° ± 1.1° to 176.3° ± 1.1° and JLCA changed from 2.0° ± 0.3° to 1.8° ± 0.3° without a statistically significant difference. From DL to SL stances, the HKA angle decreased from 176.3° ± 1.1° to 174.4° ± 1.1° (p < 0.05) and the JLCA increased from 1.8° ± 0.3° to 2.6° ± 0.3° (p < 0.05). A significant correlation was found between ΔHKA and ΔJLCA between the DL and the SL stances (R2 = 0.46; p = 0.01). CONCLUSION: Varus malalignment increases with weight-bearing loading from double-leg to single-leg stances with an associated JLCA increase. Thus, single-leg stance radiographs may be useful to correct preoperative planning considering patient-specific changes in JLCA. LEVEL OF CLINICAL EVIDENCE: III, retrospective comparative study.

Interimplant femoral fractures.

The number of hip or knee arthroplasties, and internal fixations of the proximal and distal femur, is increasing in proportion to the growing and ageing population, whose life expectancy is lengthening. Thus, fractures of the femur between proximal and distal implants, although rare, are becoming more frequent. Women over the age of 70, with fragile bones and whose ends of the two implants are close to each other ("kissing implants") are particularly vulnerable to them. Reliable and reproducible fracture classifications exist when it comes to 2 prostheses, but they are less well established in the presence of one, or even two, non-prosthetic implants. Their treatment is difficult and must consider the possibility of fracture consolidation while ensuring or restoring the stability and role of the implants. Whether it is the main element of treatment or a complement to prosthesis revision, locked plating forms the basis of the treatment but it must be rigorous, considering that failures are mainly the result of technical errors. Other more invasive treatments (total femoral arthroplasty, cortical sleeves) are offered more rarely if consolidation appears compromised.

Anterior cruciate ligament reconstruction in the over-50s. A prospective comparative study between surgical and functional treatment.

INTRODUCTION: In patients aged over-50 years, although data are sparse, results of anterior cruciate ligament (ACL) surgery are good if selection is correctly performed. However, non-operative treatment is usually proposed for this age group, as patients generally prefer just to scale down their sports activities. Non-operative results are acceptable, but with a high risk of residual instability, secondary lesions and lifestyle alteration. The main aim of the present study was to compare results between surgical versus non-surgical treatment of ACL tear in over-50 year-olds. Secondary objectives comprised assessing prognostic factors for poor functional outcome, and comparing the 2 groups epidemiologically to identify clinical decision-making factors. The study hypothesis was that results are comparable between operative and non-operative treatment of ACL tear. MATERIAL AND METHOD: Three hundred twenty patients were followed up prospectively: 92 non-surgical (NS group) and 288 surgical (S group). Classical epidemiological data were collected. Clinical laxity, differential laximetry, KOOS, IKDC, Tegner and ACL-RSI scores and radiologic assessment were collected pre- and postoperatively, as were intraoperative data. Early and late complications were collected. RESULTS: All patients were followed up. Patients were principally female, and were older, less athletic, with more stable knee and less severe functional impact in the NS group. Functional scores improved in both groups, and especially in group S, where sports scores were also better. In the NS group, laximetry at follow-up correlated with preoperative marked pivot-shift (p=0.024). Severe differential laxity was predictive of poor IKDC score (p=0.06). In the S group, laximetry at follow-up correlated with preoperative explosive pivot-shift (p<0.001), lateral meniscal lesion (p=0.007), use of hamstring tendon (p=0.007), and non-operated early complications (p=0.004). Factors for poor global KOOS score in group S comprised female gender (p<0.001), high BMI (p<0.001) and skiing (p=0.038). Factors for poor Tegner scores comprised skiing or team sport (p<0.05), isolated moderate medial osteoarthritis (p=0.01), and non-operated early complications (p=0.022). Factors for poor IKDC score comprised female gender (p=0.064), and non-operated early complications (p=0.019). Complications did not differ between groups. DISCUSSION/CONCLUSION: Results were satisfactory in both groups, with significant improvement in functional scores, but were better in group S. For NS patients, pivot sport was barely feasible and sports activity scores decreased. In case of severe laxity at diagnosis, surgical treatment should be proposed. LEVEL OF EVIDENCE: III; non-randomized prospective comparative series.

Orientation and end zone of the osteotomy cut for high tibial osteotomy: Influence on the risk of lateral hinge fracture. A finite element analysis.

INTRODUCTION: the hinge plays a fundamental role in the support and consolidation of a high tibial osteotomy. The objective of this work was to analyse the influence of the end zone of the osteotomy cut and its orientation in relation to the articular joint line (JL) on the risk of hinge fracture. HYPOTHESIS: a specific orientation and end zone of the osteotomy cut can be utilised to decrease the risk of hinge fracture. MATERIAL AND METHOD: a finite element (FE) model was used to reproduce the proximal portion of the tibia and the proximal tibiofibular joint with transverse isotropic elastic bone properties. A 1.27mm thick, complete, anteroposterior saw cut was made with a U-shaped saw blade. Five proximal and lateral tibial zones were used according to Nakamura et al corresponding to the end zones of the osteotomy cut. Three angulations of the cut relative to the JL were defined: 10°, 15°, 20°. The tests consisted of simulating 15 possible situations (3 angulations for each of the 5 end zones) on this model. These simulations made it possible to identify the existence of a local stress concentration (von Mises, in MPa) at the level of the hinge, corresponding to the main judgment criterion. RESULTS: If we consider only the end zones of the osteotomy cut, regardless of its angulation with respect to the JL, the zone which presents, on average, the lowest local stress concentration is the AM zone (40.3MPa). If we consider only the angulation of the osteotomy cut, with respect to the JL, regardless of the end zone of the cut, the angulation that locally concentrates, on average, the least stress is an angulation at 10° (147.7MPa). Finally, it is important to define the best end zone of the osteotomy cut for each angulation value in relation to the JL: for an angulation of 10°, the end zone must be in AM (38MPa), but also for an angulation of 15° (45MPa), and for an angulation of 20° (38MPa). DISCUSSION-CONCLUSION: With the inherent caveats of the experimental conditions, the hypothesis is confirmed. An end zone of the osteotomy cut exists (AM) and an orientation (10°) that induces the lowest local stress concentration and therefore the least likely to induce lateral hinge fracture. However, the orientation of the osteotomy cut is also a matter of surgical habit, especially regarding complementary osteotomy of the tibial tuberosity that some may want to avoid. Thus, it is equally important to know the best end zone associated with a given angulation of the cut in relation to the JL, which according to these results is the AM zone for each angulation. This information helps guide the operator in their surgical practices according to their habits. LEVEL OF EVIDENCE: V, expert opinion.

Lateral femoral closing wedge osteotomy in genu varum.

The distal femoral valgisation osteotomy has a variety of indications due to enhanced understanding of segmental deformities of the lower limb. Historically, an overall varus deformity was corrected at the tibia, and a valgus deformity at the femur. This approach of performing an "all in the tibia" correction for an overall varus can nevertheless lead to abnormal postoperative morphology because it is non-anatomical; creating joint line obliquity, and potentially shear stress on the cartilage. An original lateral femoral closing wedge osteotomy technique is described, allowing the correction of a genu varum of femoral or mixed origin, in the event of an associated tibial valgisation osteotomy. The detailed technique minimizes the risk of a hinge fracture while improving post-operative outcomes.

Osteotomy around the knee is planned toward an anatomical bone correction in less than half of patients.

INTRODUCTION: In cases where the femur or tibial deformity is not correctly analysed, the corrective osteotomies may result in an oblique joint line. The aim of this study was to assess the preoperative deformity of patients due to undergo corrective osteotomy and the resulting abnormal tibial and femoral morphologies after the planned correction using 3D software. METHODS: CT scans of 327 patients undergoing corrective osteotomy were retrospectively included. Each patient was planned using a software application and the simulated correction was validated by the surgeon. Following the virtual osteotomy, tibial and femoral coronal angular values were considered abnormal if the values were outside 97.5% confidence intervals for non-osteoarthritis knees. After virtual osteotomy, morphological abnormalities were split into two types. Type 1 was an under/overcorrection at the site of the osteotomy resulting in abnormal bone morphology. A type 2 was defined as an error in the site of the correction, resulting in an uncorrected abnormal bone morphology. RESULTS: The global rate of planned abnormalities after tibial virtual osteotomy was 50.7% (166/327) with abnormalities type 1 in 44% and type 2 in 6.7%. After femoral virtual osteotomy the global rate was 6.7% (22/327) with only abnormalities type 1. A lower preoperative HKA was significantly associated with a non-anatomical correction (R2=0.12, p<0.001) for both femoral (R2=0.06, p<0.001) and tibial (R2=0.07, p<0.001) abnormalities. CONCLUSION: Non-anatomical correction was found in more than half the cases analysed more frequently for preoperative global varus alignment. These results suggest that surgeons should considered anatomical angular values to avoid joint line obliquity. LEVEL OF EVIDENCE: III; retrospective cohort study.

Complications and failures of non-tumoral hinged total knee arthroplasty in primary and aseptic revision surgery: A review of 290 cases.

INTRODUCTION: Hinged total knee arthroplasty (TKA) implants are a commonly used option during revision or even primary surgery, but their complications are not as well known, due to the rapid adoption of gliding implants. The literature is inconsistent on this topic, with studies having a small sample size, varied follow-up duration and very different indications. This led us to carry out a large multicentre study with a minimum follow-up of 5 years to evaluate the complications after hinged TKA in a non-tumoral context based on the indications of primary arthroplasty, aseptic surgical revision or fracture treatment around the knee. HYPOTHESIS: Hinged TKA was associated with a high complication rate, no matter the indication. MATERIAL AND METHODS: Two hundred and ninety patients (290 knees) were included retrospectively between January 2006 and December 2011 at 17 sites, with a minimum follow-up of 5 years. The patients were separated into three groups: primary surgery (111 patients), aseptic revision surgery (127 patients) and surgery following a recent (<3 months) fracture (52 patients: 13 around the TKA and 39 around the knee treated by hinged TKA). Patients who had an active infection the knee of interest were excluded. All the patients were reviewed based on a standardised computer questionnaire validated by the SOFCOT. RESULTS: The mean follow-up was 71±39 months [range, 0 to 188]. Of the 290 patients included in the study, 108 patients (37%) suffered at least one complication and 55 patients (19%) had to undergo revision surgery: 16 in the primary TKA group (16/111, 14% of primary TKA), 28 in the revision surgery group (28/127, 22% of revision TKA) and 11 in the fracture treatment group (11/52, 21% of fracture TKA). The complications due to the hinged TKA for the entire cohort from most to least common were stiffness (41/290, 14%), chronic postoperative pain (37/290, 13%), infection (32/290, 11%), aseptic loosening (23/290, 8%), general complications (20/290, 7%), extensor mechanism complications (19/290, 6%), periprosthetic fracture (9/290, 3%), mechanical failure (2/290, 0.7%). In the primary TKA group, the main complication leading to re-operation was infection (12/111, 11%), while it was loosening for the revision TKA group (15/127, 12%) and infection (8/52, 15%) for the fracture TKA group. DISCUSSION: The 37% complication rate for hinged TKA implants is high, with 19% of them requiring re-operation. The frequency of complications differed depending on the context in which the hinged implant was used (primary, revision, fracture). The complications requiring revision surgery were major ones that prevented patients from preserving their autonomy (infection, symptomatic loosening, fracture, implant failure). The most found complications - stiffness and chronic pain - rarely led to revision. LEVEL OF EVIDENCE: IV; retrospective cohort study.