The Unloading Effect of Supramalleolar Versus Sliding Calcaneal Osteotomy for Treatment of Osteochondral Lesions of the Medial Talus: A Biomechanical Study.

Background: In patients with osteochondral lesion, defects of the medial talus, or failed cartilage surgery, a periarticular osteotomy can unload the medial compartment. Purpose: To compare the effects of supramalleolar osteotomy (SMOT) versus sliding calcaneal osteotomy (SCO) for pressure redistribution and unloading of the medial ankle joint in normal, varus-aligned, and valgus-aligned distal tibiae. Study Design: Controlled laboratory study. Methods: Included were 8 cadaveric lower legs with verified neutral ankle alignment (lateral distal tibial angle [LDTA] = 0°) and hindfoot valgus within normal range (0°-10°). SMOT was performed to modify LDTA between 5° valgus, neutral, and 5° varus. In addition, a 10-mm lateral SCO was performed and tested in each position in random order. Axial loading (700 N) of the tibia was applied with the foot in neutral alignment in a customized testing frame. Pressure distribution in the ankle joint and subtalar joint, center of force, and contact area were recorded using high-resolution Tekscan pressure sensors. Results: At neutral tibial alignment, SCO unloaded the medial joint by a mean of 10% ± 10% or 66 ± 51 N (P = .04) compared with 6% ± 12% or 55 ± 72 N with SMOT to 5° valgus (P = .12). The achieved deload was not significantly different (ns) between techniques. In ankles with 5° varus alignment at baseline, SMOT to correct LDTA to neutral insufficiently addressed pressure redistribution and increased medial load by 6% ± 9% or 34 ± 33 N (ns). LDTA correction to 5° valgus (10° SMOT) unloaded the medial joint by 0.4% ± 14% or 20 ± 75 N (ns) compared with 9% ± 11% or 36 ± 45 N with SCO (ns). SCO was significantly superior to 5° SMOT (P = .017) but not 10° SMOT. The subtalar joint was affected by both SCO and SMOT, where SCO unloaded but SMOT loaded the medial side. Conclusion: SCO reliably unloaded the medial compartment of the ankle joint for a neutral tibial axis. Changes in the LDTA by SMOT did not positively affect load distribution, especially in varus alignment. The subtalar joint was affected by SCO and SMOT in opposite ways, which should be considered in the treatment algorithm. Clinical Relevance: SCO may be considered a reliable option for beneficial load-shifting in ankles with neutral alignment or 5° varus malalignment.

Three-dimensional analysis of functional femoral antetorsion and the position of the greater trochanter in high-grade patellofemoral dysplastic knees.

BACKGROUND: The relationship between functional femoral antetorsion, the greater trochanter (GT) position and anatomical antetorsion has been demonstrated in patients with a primary hip pathology. However, the functional antetorsion and GT position have not been analyzed in patellofemoral dysplastic knees. The aim of this study was to develop a three-dimensional (3D) measurement to quantify the functional femoral antetorsion and position of the GT and to analyze these measurements in a cohort of high-grade patellofemoral dysplastic knees. METHOD: A 3D measurement was developed to analyze functional antetorsion and the axial position of the GT and assessed in 100 cadaveric femora. For validity and repeatability testing, inter- and intra-observer reliability were determined using intraclass correlation coefficients (ICCs). These measurements were then evaluated in a cohort of 19 high-grade patellofemoral dysplastic knees (Dejour type C, D). The relationship between anatomical antetorsion, functional antetorsion and GT position were reported. RESULTS: Inter- and intra-reader reliability for 3D functional antetorsion and axial position of the GT demonstrated a minimum ICC of 0.96 (P < 0.001). Anatomical and functional antetorsion demonstrated a highly linear relationship (R2 = 0.878; P < 0.001) in high-grade patellofemoral dysplastic knees. The mean difference between anatomical and functional antetorsion decreased with increasing anatomical antetorsion (R2 = 0.25; P = 0.031, indicating a more anterior position of the GT relative to the femoral neck axis. CONCLUSION: In high-grade patellofemoral dysplastic knees, the GT is located more anteriorly, relative to the femoral neck axis, with increasing anatomical antetorsion and correction osteotomy may result in an excessively anterior position of the GT.

Total hip arthroplasty through the direct anterior approach for sequelae of Legg-Calvé-Perthes disease.

INTRODUCTION: Due to multiplanar deformities of the hip, total hip arthroplasty (THA) for sequelae of Legg-Calvé-Perthes disease (LCPD) is often technically demanding. This study aimed to compare the clinical and radiographic outcomes of patients with sequelae of LCPD undergoing THA through the direct anterior approach (DAA) and non-anterior approaches to the hip. METHODS: All patients with sequelae of LCPD who underwent primary THA between 2004 and 2018 (minimum follow-up: 2 years) were evaluated and separated into two groups: THA through the DAA (Group AA), or THA through non-anterior approaches to the hip (Group non-AA). Furthermore, a consecutive control group of patients undergoing unilateral THA through the DAA for primary hip osteoarthritis (Group CC) was retrospectively reviewed for comparison. RESULTS: Group AA comprises 14 hips, group non-AA 17 hips and group CC 30 hips. Mean follow-up was 8.6 (± 5.2; 2-15), 9.0 (± 4.6; 3-17) and 8.1 (± 2.2; 5-12) years, respectively. At latest follow-up, Harris Hip Score was 90 (± 20; 26-100), 84 (± 15; 57-100), and 95 (± 9; 63-100) points, respectively. Overall, 6 patients treated for LCPD (each 3 patient in the AA and non-AA group) developed postoperative sciatic nerve palsy, of which only one was permanent. Complication-related revision rate at the latest follow-up was 15% in the AA-group and 25% in the non-AA group, respectively. CONCLUSION: THA through the DAA might be a credible option for the treatment of sequelae of LCPD with comparable complication rates and functional outcomes to non-anterior approaches.

No relevant mechanical leg axis deviation in the frontal and sagittal planes is to be expected after subtrochanteric or supracondylar femoral rotational or derotational osteotomy.

PURPOSE: The purpose of this study was to investigate if one level of corrective femoral osteotomy (subtrochanteric or supracondylar) bears an increased risk of unintentional implications on frontal and sagittal plane alignment in a simulated clinical setting. METHODS: Out of 100 cadaveric femora, 23 three-dimensional (3-D) surface models with femoral antetorsion (femAT) deformities (> 22° or < 2°) were investigated, and femAT normalized to 12° with single plane rotational osteotomies, perpendicular to the mechanical axis of the femur. Change of the frontal and sagittal plane alignment was expressed by the mechanical lateral distal femoral angle (mLDFA) and the posterior distal femoral angle (PDFA), respectively. The influence of morphologic factors of the femur [centrum-collum-diaphyseal (CCD) angle and antecurvatum radius (ACR)] were assessed. Furthermore, position changes of the lesser (LT) and greater trochanters (GT) in the frontal and sagittal plane compared to the hip centre were investigated. RESULTS: Mean femoral derotation of the high-antetorsion group (n = 6) was 12.3° (range 10-17°). In the frontal plane, mLDFA changed a mean of 0.1° (- 0.06 to 0.3°) (n.s.) and - 0.3° (- 0.5 to - 0.1) (p = 0.03) after subtrochanteric and supracondylar osteotomy, respectively. In the sagittal plane, PDFA changed a mean of 1° (0.7 to 1.1) (p = 0.03) and 0.3° (0.1 to 0.7) (p = 0.03), respectively. The low-antetorsion group (n = 17) was rotated by a mean of 13.8° (10°-23°). mLDFA changed a mean of - 0.2° (- 0.5° to 0.2°) (p < 0.006) and 0.2° (0-0.5°) (p < 0.001) after subtrochanteric and supracondylar osteotomy, respectively. PDFA changed a mean of 1° (- 2.3 to 1.3) (p < 0.01) and 0.5° (- 1.9 to 0.3) (p < 0.01), respectively. The amount of femAT correction was associated with increased postoperative deviation of the mechanical leg axis (p < 0.01). Using multiple regression analysis, no other morphological factors were found to influence mLDFA or PDFA. Internal rotational osteotomies decreased the ischial-lesser trochanteric space by < 5 mm in both the frontal and sagittal plane (p < 0.001). CONCLUSIONS: In case of femAT correction of ≤ 20°, neither subtrochanteric nor supracondylar femoral derotational or rotational osteotomies have a clinically relevant impact on frontal or sagittal leg alignment. A relevant deviation in the sagittal (but not frontal plane) might occur in case of a > 25° subtrochanteric femAT correction. LEVEL OF EVIDENCE: IV.

Tibial tunnel enlargement is affected by the tunnel diameter-screw ratio in tibial hybrid fixation for hamstring ACL reconstruction.

INTRODUCTION: There is no evidence on screw diameter with regards to tunnel size in anterior cruciate ligament reconstruction (ACLR) using hybrid fixation devices. The hypothesis was that an undersized tunnel coverage by the tibial screw leads to subsequent tunnel enlargement in ACLR in hybrid fixation technique. METHODS: In a retrospective case series, radiographs and clinical scores of 103 patients who underwent primary hamstring tendon ACLR with a hybrid fixation technique at the tibial site (interference screw and suspensory fixation) were obtained. Tunnel diameters in the frontal and sagittal planes were measured on radiographs 6 weeks and 12 months postoperatively. Tunnel enlargement of more than 10% between the two periods was defined as tunnel widening. Tunnel coverage ratio was calculated as the tunnel diameter covered by the screw in percentage. RESULTS: Overall, tunnel widening 12 months postoperatively was 23.1 ± 17.1% and 24.2 ± 18.2% in the frontal and sagittal plane, respectively. Linear regression analysis revealed the tunnel coverage ratio to be a negative predicting risk factor for tunnel widening (p = 0.001). The ROC curve analysis provided an ideal cut-off for tunnel enlargement of > 10% at a tunnel coverage ratio of 70% (sensitivity 60%, specificity 81%, AUC 75%, p < 0.001). Patients (n = 53/103) with a tunnel coverage ratio of < 70% showed significantly higher tibial tunnel enlargement of 15% in the frontal and sagittal planes. The binary logistic regression showed a significant OR of 6.9 (p = 0.02) for tunnel widening > 10% in the frontal plane if the tunnel coverage ratio was < 70% (sagittal plane: OR 14.7, p = 0.001). Clinical scores did not correlate to tunnel widening. CONCLUSION: Tibial tunnel widening was affected by the tunnel diameter coverage ratio. To minimize the likelihood of disadvantageous tunnel expansion-which is of importance in case of revision surgery-an interference screw should not undercut the tunnel diameter by more than 1 mm.

Surgical fixation techniques in four-corner fusion of the wrist: a systematic review of 1103 cases.

BACKGROUND: Four-corner fusion (4CF) is a known treatment option for degenerative wrist conditions. Different techniques may be used and there is no general consensus on best implant. As such, it was the purpose of the current systematic review to compare fusion rates and outcomes depending on the fixation technique. METHODS: The systematic review was registered in the international prospective register of systematic reviews (PROSPERO): CRD42020164301. It followed the PRISMA guidelines. Original articles were screened using the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and Web of Science Core Collection. Studies reporting on outcome for 4CF surgery were included. Studies with a minimum Level IV of evidence were considered eligible. Quality assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. RESULTS: A total of 29 studies met the inclusion criteria, for a total of 1103 wrists. The mean age was 41.8 years (range 19-83). Mean follow-up overall was 43.5 months (range 24-146 months). Reported fusion weighted rates were >90% and did not differ significantly between techniques. Reoperations due to different reasons occurred in 135 (12%) of all 1103. There was significant data heterogeneity regarding fusion rates (I2 = 70%). Inconsistency and heterogeneity in data reporting did not allow meta-analysis with direct data pooling and comparison of subgroups. CONCLUSIONS: Satisfactory fusion rates (over 90%) can be achieved independent of the fixation technique used in 4-corner arthrodesis. Due to the high data heterogeneity and reporting inconsistency across studies, no statements regarding PROMs, ROM or grip strength can be made. LEVEL OF EVIDENCE: Systematic Review of Level IV Studies.

Excessive femoral torsion is not associated with patellofemoral pain or instability if TKA is functionally aligned and the patella denervated.

PURPOSE: Recent data suggest that individual morphologic factors should be respected to restore preoperative patellofemoral alignment and thus reduce the likelihood of anterior knee pain. The goal of this study was to investigate the effect of excessive femoral torsion (FT) on clinical outcome of TKA. METHODS: Patients who underwent TKA and complete preoperative radiographic evaluation including a long-leg radiograph and CT scan were included. 51 patients showed increased FT of > 20° and were matched for age/sex to 51 controls (FT < 20°). Thirteen patients were lost to follow-up. Thirty-eight matched pairs were compared after a 2 year follow-up clinically (Kujala and patellofemoral score for TKA) and radiographically (FT, frontal leg axis, TT-TG, patellar thickness, patellar tilt, and lateral displacement of patella). Functional alignment of TKA was performed (hybrid-technique). All patellae were denervated but no patella was resurfaced. RESULTS: There was no significant difference between clinical scores two years after surgery between patients with normal and excessive FT (n.s.). Kujala score was 64.3 ± 16.7 versus 64.8 ± 14.4 (n.s.), and patellofemoral score for TKA was 74.3 ± 21 versus 78.5 ± 20.7 (n.s.) for increased FT group and control group, respectively. There was no correlation between preoperative FT and clinical scores. Other radiographic parameters were similar between both groups. No correlations between clinical outcomes and preoperative/postoperative frontal leg axis or total leg axis correction were found (n.s.). CONCLUSION: If the leg axis deformity is corrected to a roughly neutral alignment during cemented TKA, including patellar denervation, then excessive FT was not associated with patellofemoral pain or instability. LEVEL OF EVIDENCE: Prospective comparative study, level II.

Postoperative fever: differences between elective vs. traumatic hip, knee and shoulder arthroplasty.

BACKGROUND: It is unclear whether there is a difference in the incidence of postoperative fever (POF) between hip, knee and shoulder arthroplasty. The influence of a trauma setting has not been investigated. METHODS: A retrospective review was performed on 675 joint replacement surgeries (hip, knee, shoulder arthroplasty) in an elective or trauma setting over a 2 year period (2016-2018). Patient demographics and perioperative/postoperative parameters were investigated. The fever curve was characterized. The results and costs of any fever-related diagnostic workup were reviewed. RESULTS: A total of 89 patients (13.2%) experienced a POF ≥ 38.0 °C, only 21 patients (3.1%) a POF ≥ 38.5 °C (of the latter: 4.6% of hip arthroplasties, 0.6% of knee arthroplasties, 0% of shoulder arthroplasties). There was a significantly greater risk (OR 3.88) for POF ≥ 38.5 °C in trauma total hip arthroplasty (THA) compared to elective THA (10.6 vs. 3.0%; p < 0.01). Differences in POF rate between the various joint areas were statistically insignificant when comparing only elective and trauma cases with each other, even though there was a trend for higher rates in hip surgery. Patients experiencing POF ≥ 38.5 °C were more often males (p < 0.01) and had an increased intraoperative blood loss (p = 0.03) and longer hospital stay (p < 0.01). There was only 1/89 POF patients developing an early periprosthetic joint infection. The cost of a positive fever workup (3/27 patients, 11.1%) leading to a new diagnosis and treatment was 2045 US$. CONCLUSION: POF ≥ 38.5 °C was more frequent in traumatic THA compared to elective THA. A trend of difference between POF rates between the different joint areas was statistically insignificant after separating elective and traumatic cases. The risk of developing an early periprosthetic joint infection was not increased in POF. A fever-related diagnostic workup was rarely helpful in the absence of clinical symptoms.

Extent of posterolateral tibial plateau impaction fracture correlates with anterolateral complex injury and has an impact on functional outcome after ACL reconstruction.

PURPOSE: The impact of posterolateral tibial plateau impaction fractures (TPIF) on posttraumatic knee stability in the setting of primary anterior cruciate ligament (ACL) tear is unknown. The main objective was to determine whether increased bone loss of the posterolateral tibial plateau is associated with residual rotational instability and impaired functional outcome after ACL reconstruction. METHODS: A cohort was identified in a prospective enrolled study of patients suffering acute ACL injury who underwent preoperative standard radiographic diagnostics and clinical evaluation. Patients were included when scheduled for isolated single-bundle hamstring autograft ACL reconstruction. Exclusion criteria were concurrent anterolateral complex (ALC) reconstruction (anterolateral tenodesis), previous surgery or symptoms in the affected knee, partial ACL tear, multi-ligament injury with an indication for additional surgical intervention, and extensive cartilage wear. On MRI, bony (TPIF, tibial plateau, and femoral condyle morphology) and ligament status (ALC, concomitant collateral ligament, and meniscus injuries) were assessed by a musculoskeletal radiologist. Clinical evaluation consisted of KT-1000, pivot-shift, and Lachman testing, as well as Tegner activity and IKDC scores. RESULTS: Fifty-eight patients were included with a minimum follow-up of 12 months. TPIF was identified in 85% of ACL injuries (n = 49). The ALC was found to be injured in 31 of 58 (53.4%) cases. Pearson analysis showed a positive correlation between TPIF and the degree of concomitant ALC injury (p < 0.001). Multiple regression analysis revealed an increased association of high-grade TPIF with increased lateral tibial convexity (p = 0.010). The high-grade TPIF group showed worse postoperative Tegner scores 12 months postoperatively (p = 0.035). CONCLUSION: Higher degrees of TPIFs are suggestive of a combined ACL/ALC injury. Moreover, patients with increased posterolateral tibial plateau bone loss showed lower Tegner activity scores 12 months after ACL reconstruction. LEVEL OF EVIDENCE: III.

Hybrid fixation of unicompartmental knee arthroplasty shows equivalent short-term implant survivorship and clinical scores compared to standard fixation techniques.

INTRODUCTION: There is a paucity of data regarding hybrid-fixated unicompartmental knee arthroplasty (UKA), and no study directly compared all three available fixation techniques (cementless, cemented, and hybrid). The hypothesis was that hybrid fixation might have a lower incidence of radiolucent lines (RLL) than cemented UKA, with equivalent outcomes to uncemented UKA. MATERIALS AND METHODS: A total of 104 UKA with a minimal follow-up of 1 year were retrospectively included, of which 40 were cemented, 41 cementless, and 23 hybrid prostheses. The functional outcomes scores included the Oxford Knee (OKS), Subjective Knee (SKS), and Forgotten Joint scores (FJS). RLLs, subsidence, and component positioning were assessed on radiographs. RESULTS: At a mean follow-up of 28 months, the survival rate was 95% for cemented UKA and 100% for the cementless and hybrid UKA (n.s.), respectively. Postoperative FJS (93 vs. 82 points, p = 0.007) and SKS (4.7 vs. 4.1 points, p = 0.001) were better in cementless than cemented UKA, with hybrid-fixated UKA in between the two (90 and 4.4 points, n.s.). Improvement of OKS preoperatively to postoperatively did not differ between the groups (n.s.). RLLs were more frequent in cemented (23%) compared to cementless (5%, p = 0.021) and hybrid UKA (9%, n.s.). With an incidence of 12%, subsidence occurred more commonly in cementless UKA compared to cemented (5%) and hybrid (0%) (n.s.) UKA. CONCLUSION: Hybrid fixation achieves equivalent results to standard UKA fixation techniques regarding implant survival and functional and radiological outcomes. Therefore, the hybrid fixation technique seems to be a valuable alternative as it combines the advantages of cemented tibial components with those of uncemented femoral components. LEVEL OF EVIDENCE: III.

The relationship between pelvic tilt, frontal, and axial leg alignment in healthy subjects.

INTRODUCTION: The relationship between anterior pelvic tilt and overall sagittal alignment has been well-described previously. However, the relationship between pelvic tilt, frontal, and axial leg alignment remains unclear. The aim of the study was to analyze the relationship between pelvic tilt and frontal and axial leg alignment in healthy subjects. MATERIAL AND METHODS: Thirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph. Pelvic parameters (pelvic tilt, pelvic incidence, sacral slope), hip-knee-ankle angle (HKA), femoral antetorsion and tibial torsion were measured using SterEOS (EOS Imaging) software. EOS was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of HKA, femoral antetorsion, tibial torsion and gender on pelvic tilt was analyzed in a univariate correlation and multiple regression model. RESULTS: Sixteen female subjects and 14 male subjects with a mean age of 27.1 years ± 10 (range 20-67) were included. HKA, femoral antetorsion, and tibial torsion correlated with anterior pelvic tilt in univariate analysis (all p < 0.05). Anterior pelvic tilt increased 1.1° (95% CI: 0.7 to 1.5) per 1° of knee valgus (p < 0.001) and 0.5° (95% CI: 0.3 to 0.7) per 1° of external tibial torsion (p < 0.001). Overall, linear regression model fit explained 39% of variance in pelvic tilt by the HKA, femoral antetorsion and tibial torsion (R2 = 0.385; p < 0.001). CONCLUSION: Valgus alignment and increasing tibial torsion demonstrated a weak correlation with an increase in anterior pelvic tilt in healthy subjects when placing their feet anteriorly. The relationship between frontal, axial leg alignment and pelvic tilt needs to be considered in patients with multiple joint disorders at the hip, knee and spine. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the pelvic tilt when the FPA is kept constant.

The winking sign is an indicator for increased femorotibial rotation in patients with recurrent patellar instability.

PURPOSE: Rotation of the tibia relative to the femur was recently identified as a contributing risk factor for patellar instability, and correlated with its severity. The hypothesis was that in patellofemoral dysplastic knees, an increase in femorotibial rotation can be reliably detected on anteroposterior (AP) radiographs by an overlap of the lateral femoral condyle over the lateral tibial eminence. METHODS: Sixty patients (77 knees) received low-dose computed tomography (CT) of the lower extremity for assessment of torsional malalignment due to recurrent patellofemoral instability. Three-dimensional (3D) surface models were created to assess femorotibial rotation and its relationship to other morphologic risk factors of patellofemoral instability. On weight-bearing AP knee radiographs, a femoral condyle/lateral tibial eminence superimposition was defined as a positive winking sign. Using digitally reconstructed radiographs of the 3D models, susceptibility of the winking sign to vertical/horizontal AP knee radiograph malrotation was investigated. RESULTS: A positive winking sign was present in 30/77 knees (39.0%) and indicated a 6.3 ± 1.4° increase in femorotibial rotation (p < 0.001). Femoral condyle/tibial eminence superimposition of 1.9 mm detected an increased femorotibial rotation (> 15°) with 43% sensitivity and 90% specificity (AUC = 0.72; p = 0.002). A positive winking sign (with 2 mm overlap) disappeared in case of a 10° horizontally or 15° vertically malrotated radiograph, whereas a 4 mm overlap did not disappear at all, regardless of the quality of the radiograph. In absence of a winking sign, on the other hand, no superimposition resulted within 20° of vertical/horizontal image malrotation. Femorotibial rotation was positively correlated to TT-TG (R2 = 0.40, p = 0.001) and patellar tilt (R2 = 0.30, p = 0.001). CONCLUSIONS: The winking sign reliably indicates an increased femorotibial rotation on a weight-bearing AP knee radiograph and could prove useful for day-by-day clinical work. Future research needs to investigate whether femorotibial rotation is not only a prognostic factor but a potential surgical target in patients with patellofemoral disorders. LEVEL OF EVIDENCE: III.

Talus morphology differs between flatfeet and controls, but its variety has no influence on extent of surgical deformity correction.

BACKGROUND: Progressive collapsing foot deformity (PCFD) is a complex 3-dimensional (3-D) deformity with varying degrees of hindfoot valgus, forefoot abduction, and midfoot varus. The first aim of this study was to perform a 3-D analysis of the talus morphology between symptomatic PCFD patients that underwent operative flatfoot correction and controls. The second aim was to investigate if there is an impact of individual talus morphology on the success of operative flatfoot correction. METHODS: We reviewed all patients that underwent lateral calcaneal lengthening for correction of PCFD between 2008 and 2018 at our clinic. Radiographic flatfoot parameters on preoperative and postoperative radiographs were assessed. Additionally, 3-D surface models of the tali were generated using computed tomography (CT) data. The talus morphology of 44 flatfeet was compared to 3-D models of 50 controls without foot or ankle pain of any kind. RESULTS: Groups were comparable regarding demographics. Talus morphology differed significantly between PCFD and controls in multiple aspects. There was a 2.6° increased plantar flexion (22.3° versus 26°; p = 0.02) and medial deviation (31.7° and 33.5°; p = 0.04) of the talar head in relation to the body in PCFD patients compared to controls. Moreover, PCFD were characterized by an increased valgus (difference of 4.6°; p = 0.01) alignment of the subtalar joint. Satisfactory correction was achieved in all cases, with an improvement of the talometatarsal-angle and the talonavicular uncoverage angle of 5.6° ± 9.7 (p = 0.02) and 9.9° ± 16.3 (p = 0.001), respectively. No statistically significant correlation was found between talus morphology and the correction achieved or loss of correction one year postoperatively. CONCLUSION: The different morphological features mentioned above might be contributing or risk factors for progression to PCFD. However, despite the variety of talar morphology, which is different compared to controls, the surgical outcome of calcaneal lengthening osteotomy was not affected. LEVEL OF EVIDENCE: III.

Treatment Failures in Diabetic Foot Osteomyelitis Associated with Concomitant Charcot Arthropathy: The Role of Underlying Arteriopathy.

OBJECTIVE: Therapy for diabetic foot osteomyelitis (DFO) with Charcot neuroosteoarthropathy is challenging. In patients with diabetic Charcot osteomyelitis (DCO), both the anatomic deformity and infection must be addressed. This study assessed the outcomes of DCO therapy and variables associated with treatment failure and compared them with outcomes of DFO cases. METHODS: A single-center, retrospective, case-control study was performed to compare 93 DCO episodes with 530 DFO episodes, using Kaplan-Meier survival curves and multivariate Cox regression analyses. RESULTS: Clinical failure occurred in 21.5% of DCO compared with 22.3% in DFO episodes (p=0.89) and was associated with peripheral arterial disease (PAD) stages 3 or 4 (HR 6.1; CI 2.0-18.1) and chronic treatment with immunosuppressives (HR 7.4; CI 2.0-27.1). Major amputations were significantly more frequent in DCO (28% versus 13.6%; p<0.01) and associated with PAD stages 3 and 4 (HR 8.0; CI 2.2-29.4), smoking (HR 5.4; CI 1.2-24.6), alcohol abuse (HR 3.5; CI 1.1-10.6), and renal dialysis (HR 4.9; CI 1.3-18.9). CONCLUSIONS: Clinical treatment failures did not differ between DCO and DFO. However, patients with DCO underwent major amputation twice as often as those with DFO. Unlike widespread belief, treatment failure in DCO patients may, similar to DFO, be associated with a striking epidemiological link to severe PAD.

Mid-term subsidence and periprosthetic radiolucency of the AMIStem: a 5-year EBRA-FCA analysis.

BACKGROUND: There has been an evolution in cementless total hip arthroplasty (THA) with newer short stem designs aimed to preserve metaphyseal bone stock and facilitate implantation through minimally invasive approaches. While early subsidence has been correlated to aseptic loosening in conventional stems, there is a paucity of data regarding short stems. The current study aims to report on stem subsidence and mid-term clinical outcomes of a cementless, metaphyseal-anchored short femoral stem, specifically designed for the direct anterior approach (DAA). METHODS: Ninety-four consecutive patients (100 hips) with a minimum follow-up of 5 years following cementless THA were included in this single-center retrospective study. Subsidence was evaluated using the "Ein-Bild-Roentgen-Analyse" (EBRA). Periprosthetic radiolucency allocated to the zones of Charnley and Gruen was assessed. Additionally, demographic and implant-related factors potentially associated with increased subsidence and clinical outcomes were evaluated. RESULTS: At the last follow-up, the average stem subsidence was 1.98 ± 1.20 mm, with 48% of the implants demonstrating subsidence of > 2 mm. Periprosthetic radiolucency of > 2 mm was found in 26% of the implants in zone 1 and in 9% in zone 7, respectively. Neither the amount of subsidence nor proximal periprosthetic radiolucency was associated with aseptic loosening or worse clinical outcomes. CONCLUSIONS: Comparable to other proximally fixed short stem designs, the highest subsidence was observed within the first 3 months following implantation. No demographic or implant-related factors were found to have a statistically significant influence on stem subsidence. Periprosthetic radiolucency and subsidence of the AMISstem is not correlated with worse clinical outcomes at 5-year follow-up.

Open reduction and internal fixation might be a valuable alternative to stem revision in Vancouver B2 periprosthetic femoral fractures, irrespective of the stem's design.

BACKGROUND: The purpose of this study was to compare the clinical and radiological outcomes following open reduction and internal fixation (ORIF) of Vancouver B2 periprosthetic femoral fractures versus stem revision (SR) surgery. METHODS: Between 2004 and 2018, 39 patients were treated with SR and 31 with ORIF for a Vancouver type B2. Mean follow-up was 40.4 months for the ORIF group and 43.5 months for the SR group. 22 of 31 stems in the ORIF group were uncemented, of which 7 (23%) were short stems. Perioperative complications, intraoperative blood loss, revision rate, and mortality were recorded. Functional outcomes included Harris Hip Score, Parker Mobility Score and hip abductor strength. RESULTS: Both groups did not differ in the American Society of Anesthesiologists (ASA) score, Charlson comorbidity index, body mass index, age, and sex. Compared to SR, patients treated with ORIF had a decreased blood loss, transfusion rate, operation duration, and mortality. Total complication and re-operation rates were similar. The relative risk for complication and re-operation was 0.5 and 0.7, respectively, in favour of ORIF. CONCLUSIONS: ORIF might be a valuable alternative to SR in the treatment of Vancouver type B2 periprosthetic fractures with shorter operation duration, lower blood loss and similar complication rate compared to SR. Moreover, re-stabilization seems possible irrespective of stem's design or fixation technique. LEVEL OF EVIDENCE: Level III.

Is revision total hip arthroplasty through the direct anterior approach feasible?

BACKGROUND: To date, only limited literature exists regarding revision of total hip arthroplasty (THA) through the direct anterior approach (DAA). However, as the popularity of the DAA for primary surgery is increasing, surgeons will be confronted with the challenge of performing revision surgery through the DAA. The aim of this study was to review the potential of the DAA in the revision setting and to report the clinical results, radiologic outcomes and complication rates of 63 patients undergoing revision THA through the DAA. METHODS: From 01/2009 to 08/2017, 63 patients underwent revision THA through the DAA. Depending on the performed procedure, patients were separated into 4 groups: liner and head exchange (21 patients), revision of the acetabular cup (26 patients), revision of the femoral stem (13 patients) or revision of both components (3 patients). Postoperative complications as well as the clinical and radiological outcome were assessed retrospectively. RESULTS: At a mean follow-up of 18 months, the overall complication and re-operation rates were 14.3% and 12.7%, respectively. Specifically, the complication and re-operation rates were 14.2% and 9.5% after liner and head exchange, 15.4% after revision of the acetabular cup, 15.3% after revision of the femoral stem and 0% after revision of both components. The mean postoperative HHS at 1 year postoperatively was 91 (range 74-100). CONCLUSION: The DAA offers appropriate exposure for exchange of mobile liners and acetabular cup revision. In selected cases with appropriate stem design, femoral stem revision through the DAA is feasible. However, surgeons should be aware of the technical difficulties related to femoral revision and be prepared to extend the approach distally or perform a trochanteric osteotomy.

Influence of patient selection, component positioning and surgeon's caseload on the outcome of unicompartmental knee arthroplasty.

BACKGROUND: Implant malpositioning, low surgical caseload, and improper patient selection have been identified as essential factors, which could negatively affect the longevity of unicompartmental knee arthroplasty (UKA). The aim of the current study was to evaluate the impact of the surgeon's caseload on patient selection, component positioning, as well as component survivorship and functional outcomes following a PSI-UKA. METHODS: A total of 125 patient-specific instrumented (PSI) UKA were included. One hundred and two cases were treated by a high-volume surgeon (usage 40%) and 23 cases by a low-volume surgeon (< 10 cases/year, usage 34%). Preoperative UIS, as well as the postoperative clinical and radiologic outcome, were assessed retrospectively. RESULTS: Irrespective of the surgeon's UKA caseload, PSI allowed good accuracy in component positioning (p > 0.05). The high-volume surgeon had a more strict indication for UKA with 89% showing a UIS > 25 (considered a good indication) compared to 70% for the low-volume surgeon (p = 0.016). The low-volume surgeon achieved worse results regarding functional outcome (p < 0.05) and a tendency toward an increased risk for UKA failure (p = 0.11) compared to the high-volume surgeon. CONCLUSION: Due to potential selection errors, mostly connected to a low UKA-caseload, low-volume UKA surgeons might achieve worse outcomes. Very strict indications for UKA might be recommended in low-volume surgeons to achieve excellent clinical outcomes following a UKA.

Clinical and radiological mid- to long-term results after direct fixation of posterior malleolar fractures through a posterolateral approach.

BACKGROUND: Direct fixation of posterior malleolar fractures has been shown to lead to higher accuracy of fracture reduction compared to an indirect anterior to posterior fixation but lacks long-term clinical results. This study shows the mid- to long-term clinical and radiological outcome after direct fixation of the posterior malleolus through a posterolateral approach. MATERIALS AND METHODS: Thirty-six patients with an ankle fracture including a posterior malleolar fragment (23 × AO-44C, 12 × AO-44B, 1 × unclassifiable) treated with direct fixation of the fragment through a posterolateral approach were retrospectively evaluated. There were 24 females (67%) with a mean age of 63 (range 34-80) years and a BMI of 28 (range 19-41) kg/m2 at the time of surgery. An initial fracture-dislocation was seen in 67%. The clinical outcome was assessed with the Visual Analog Scale (VAS, 0-10 points) and the American Foot and Ankle Society (AOFAS, 0-100 points) score. Posttraumatic osteoarthritis was recorded with the Van Dijk Classification (grade 0-III). Subgroup analyses of patient- and fracture-associated risk factors (age, BMI, smoking, fracture-dislocation, postoperative articular step-off) were assessed to reveal possible negative prognostic predictors. RESULTS: After a mean follow-up of 7.9 (range 3-12) years, the median VAS was 1 (IQR 0-2) point, and the median AOFAS score was 96 (IQR 88-100) points. Ankle range of motion measurements showed a significant, but clinically irrelevant, difference in plantar- and dorsiflexion between the affected and unaffected ankle. 92% of the patients were very satisfied or satisfied with the postoperative course. 89% had no preoperative signs of ankle osteoarthritis. Osteoarthritis progression was seen in 72%, with 50% showing grade II or III osteoarthritis at the final follow-up. No significant negative prognostic factors for a worse clinical outcome could be detected. CONCLUSION: Direct fixation of posterior malleolar fractures through a posterolateral approach showed good clinical mid- to long-term results with a high satisfaction rate but substantial development of posttraumatic ankle osteoarthritis. Further studies should include CT analysis of the preoperative fracture morphology and even, perhaps, the postoperative reduction accuracy to evaluate the benefit of posterior malleolar fracture reduction in preventing ankle osteoarthritis in the long term. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for authors for a complete description of levels of evidence.