Aims. Total hip arthroplasty (THA) is considered the preferred treatment for displaced proximal femoral neck fractures. However, in many countries this option is economically unviable. To improve outcomes in financially disadvantaged populations, we studied the technique of concomitant valgus hip osteotomy and operative fixation (VOOF). This prospective serial study compares two treatment groups: VOOF versus operative fixation alone with cannulated compression screws (CCSs). Methods. In the first series, 98 hip fixation procedures were performed using CCS. After fluoroscopic reduction of the fracture, three CCSs were placed. In the second series, 105 VOOF procedures were performed using a closing wedge intertrochanteric osteotomy with a compression lag screw and lateral femoral plate. The alignment goal was to create a modified Pauwel’s fracture angle of 30°. After fluoroscopic reduction of fracture, lag screw was placed to achieve the calculated correction angle, followed by inter-trochanteric osteotomy and placement of barrel plate. Patients were followed for a minimum of two years. Results. Mean follow-up was 4.6 years (4.1 to 5.0) in the CCS group and 5.5 years (5.25 to 5.75) in the VOOF group. The mean Harris Hip Score at two-year follow-up was 83.85 in the CCS group versus 88.00 in the VOOF group (p < 0.001). At the latest follow-up, all-cause failure rate was 29.1% in the CCS group and 11.7% in the VOOF group (p = 0.003). The total cost of the VOOF technique was 7.2% of a THA, and total cost of the CCS technique was 6.3% of a THA. Conclusion. The VOOF technique decreased all-cause failure rate compared to CCS. The total cost of VOOF was 13.5% greater than CCS, but 92.8% less than a THA. Increased cost of VOOF was considered acceptable to all patients in this series. VOOF technique provides a reasonable alternative to THA in patients who cannot afford a THA procedure. Cite this article: Bone Jt Open 2023;4(5):329–337

Aims. Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°. Methods. A matched cohort of patients similar for demographics and components used but differing in preoperative coronal-plane tibiotalar valgus deformity ≥ 15° (valgus, n = 50; 52% male, mean age 65.8 years (SD 10.3), mean body mass index (BMI) 29.4 (SD 5.2)) or < 15° (control, n = 50; 58% male, mean age 65.6 years (SD 9.8), mean BMI 28.7 (SD 4.2)), underwent TAA by one surgeon. Preoperative and postoperative radiographs, Ankle Osteoarthritis Scale (AOS) pain and disability and 36-item Short Form Health Survey (SF-36) version 2 scores were collected prospectively. Ancillary procedures, secondary procedures, and complications were recorded. Results. At mean 5.1 years follow-up (SD 2.6) (valgus) and 6.6 years (SD 3.3) (controls), mean AOS scores decreased and SF-36 scores increased significantly in both groups. Improvements in scores were similar for both groups – AOS pain: valgus, mean 26.2 points (SD 24.2), controls, mean 22.3 points (SD 26.4); AOS disability: valgus, mean 41.2 points (SD 25.6); controls, mean 34.6 points (SD 24.3); and SF-36 PCS: valgus, mean 9.1 points (SD 14.1), controls, mean 7.4 points (SD 9.8). Valgus ankles underwent more ancillary procedures during TAA (40 (80%) vs 13 (26%)) and more secondary procedures postoperatively (18 (36%) vs 7 (14%)) than controls. Tibiotalar deformity improved significantly (p < 0.001) towards a normal weightbearing axis in valgus ankles. Three valgus and four control ankles required subsequent fusion, including two for deep infections (one in each group). Conclusion. Satisfactory mid-term results were achieved in patients with preoperative valgus malalignment ≥ 15°, but they required more adjunctive procedures during and after TAA. Valgus coronal-plane deformity ≥ 15° is not an absolute contraindication for TAA if associated deformities are addressed. Cite this article: Bone Joint J 2020;102-B(12):1689–1696

Valgus knee deformity can present a number of unique surgical challenges for the total knee arthroplasty (TKA) surgeon. Understanding the typical patterns of bone and soft-tissue pathology in the valgus arthritic knee is critical for appropriate surgical planning. This review aims to provide the knee arthroplasty surgeon with an understanding of surgical management strategies for the treatment of valgus knee arthritis. Lateral femoral and tibial deficiencies, contracted lateral soft tissues, attenuated medial soft tissues, and multiplanar deformities may all be present in the valgus arthritic knee. A number of classifications have been reported in order to guide surgical management, and a variety of surgical strategies have been described with satisfactory clinical results. Depending on the severity of the deformity, a variety of TKA implant designs may be appropriate for use. Regardless of an operating surgeon’s preferred surgical strategy, adherence to a step-wise approach to deformity correction is advised. Cite this article: Bone Joint J 2017;99-B(1 Supple A):60–4

Correction of valgus deformity of the hindfoot using a medial approach for a triple fusion has only recently been described for patients with tight lateral soft tissues which would be compromised using the traditional lateral approach. We present a series of eight patients with fixed valgus deformity of the hindfoot who had correction by hindfoot fusion using this approach. In addition, we further extended the indications to allow concomitant ankle fusion. The medial approach allowed us to excise medial ulcers caused by the prominent medial bony structures, giving simultaneous correction of the deformity and successful internal fixation. We had no problems with primary wound healing and experienced no subsequent infection or wound breakdown. From a mean fixed valgus deformity of 58.8° (45° to 66°) pre-operatively, we achieved a mean post-operative valgus angulation of 13.6° (7° to 23°). All the feet were subsequently accommodated in shoes. The mean time to arthrodesis was 5.25 months (3 to 9). We therefore recommend the medial approach for the correction of severe fixed valgus hindfoot deformities

It has been suggested that a supramalleolar osteotomy can return the load distribution in the ankle joint to normal. However, due to the lack of biomechanical data, this supposition remains empirical. The purpose of this biomechanical study was to determine the effect of simulated supramalleolar varus and valgus alignment on the tibiotalar joint pressure, in order to investigate its relationship to the development of osteoarthritis. We also wished to establish the rationale behind corrective osteotomy of the distal tibia. We studied 17 cadaveric lower legs and quantified the changes in pressure and force transfer across the tibiotalar joint for various degrees of varus and valgus deformity in the supramalleolar area. We assumed that a supramalleolar osteotomy which created a varus deformity of the ankle would result in medial overload of the tibiotalar joint. Similarly, we thought that creating a supramalleolar valgus deformity would cause a shift in contact towards the lateral side of the tibiotalar joint. The opposite was observed. The restricting role of the fibula was revealed by carrying out an osteotomy directly above the syndesmosis. In end-stage ankle osteoarthritis with either a valgus or varus deformity, the role of the fibula should be appreciated and its effect addressed where appropriate

Cubitus varus and valgus are the most common complications of supracondylar and lateral condylar fractures. Various combinations of osteotomy and fixation have been described to correct these deformities but each is associated with significant complications. In this study, we used distraction osteogenesis and Ilizarov frame fixation to treat 24 elbows in 23 patients with cubitus varus or valgus. Their clinical outcome was evaluated using the protocol of Bellemore et al. The mean time to follow-up was 18.3 months (10 to 36) and the mean time to frame removal was 13.5 weeks (8 to 20). The mean carrying angle was corrected from −18.7° (−10° to −30°) to 6.1° (2° to 10°) in patients with cubitus varus and from 36.5° (25° to 45°) to 9.4° (4° to 15°) in patients with cubitus valgus. There were 18 excellent and six good results. The Ilizarov method with gradual distraction is a safe, stable, adjustable and versatile method of treating deformities at the elbow without the problems of an unsightly scar or limited range of movement, and gives a good clinical and radiological outcome. Tardy ulnar nerve palsy should be treated first by anterior transposition

Total knee arthroplasty (TKR) using a medial capsular approach gives worse results in arthritic knees with valgus deformity than in those in varus, usually because of swelling, poor wound healing and stiffness, instability, recurrent valgus deformity and poor patellar tracking. A technique for replacement TKR of valgus knees using a lateral capsular approach was described several years ago, but was not routinely adopted because of the difficulties with and complexity of the procedure which included deliberate elevation of the tibial tubercle. In order to avoid this we have modified and simplified the procedure. Our preliminary results suggest that this lateral approach is safe and may give a better outcome than that through the medial capsule for the replacement of valgus knees

We describe the mid-term results of a prospective study of total knee replacement in severe valgus knees using an osteotomy of the lateral femoral condyle and computer navigation. There were 15 knees with a mean valgus deformity of 21° (17° to 27°) and a mean follow-up of 28 months (24 to 60). A cemented, non-constrained fixed bearing, posterior-cruciate-retaining knee prosthesis of the same design was used in all cases (Columbus-B. Braun; Aesculap, Tuttlingen, Germany). All the knees were corrected to a mean of 0.5° of valgus (0° to 2°). Flexion of the knee had been limited to a mean of 85° (75° to 110°) pre-operatively and improved to a mean of 105° (90° to 130°) after operation. The mean Knee Society score improved from 37 (30 to 44) to 90 points (86 to 94). Osteotomy of the lateral femoral condyle combined with computer-assisted surgery gave an excellent mid-term outcome in patients undergoing total knee replacement in the presence of severe valgus deformity

Aims. This study aimed to analyze kinematics and kinetics of the tibiofemoral joint in healthy subjects with valgus, neutral, and varus limb alignment throughout multiple gait activities using dynamic videofluoroscopy. Methods. Five subjects with valgus, 12 with neutral, and ten with varus limb alignment were assessed during multiple complete cycles of level walking, downhill walking, and stair descent using a combination of dynamic videofluoroscopy, ground reaction force plates, and optical motion capture. Following 2D/3D registration, tibiofemoral kinematics and kinetics were compared between the three limb alignment groups. Results. No significant differences for the rotational or translational patterns between the different limb alignment groups were found for level walking, downhill walking, or stair descent. Neutral and varus aligned subjects showed a mean centre of rotation located on the medial condyle for the loaded stance phase of all three gait activities. Valgus alignment, however, resulted in a centrally located centre of rotation for level and downhill walking, but a more medial centre of rotation during stair descent. Knee adduction/abduction moments were significantly influenced by limb alignment, with an increasing knee adduction moment from valgus through neutral to varus. Conclusion. Limb alignment was not reflected in the condylar kinematics, but did significantly affect the knee adduction moment. Variations in frontal plane limb alignment seem not to be a main modulator of condylar kinematics. The presented data provide insights into the influence of anatomical parameters on tibiofemoral kinematics and kinetics towards enhancing clinical decision-making and surgical restoration of natural knee joint motion and loading. Cite this article: Bone Joint Res 2024;13(9):485–496

The aim of our study was to investigate whether placing of the femoral component of a hip resurfacing in valgus protected against spontaneous fracture of the femoral neck. We performed a hip resurfacing in 20 pairs of embalmed femora. The femoral component was implanted at the natural neck-shaft angle in the left femur and with a 10° valgus angle on the right. The bone mineral density of each femur was measured and CT was performed. Each femur was evaluated in a materials testing machine using increasing cyclical loads. In specimens with good bone quality, the 10° valgus placement of the femoral component had a protective effect against fractures of the femoral neck. An adverse effect was detected in osteoporotic specimens. When resurfacing the hip a valgus position of the femoral component should be achieved in order to prevent fracture of the femoral neck. Patient selection remains absolutely imperative. In borderline cases, measurement of bone mineral density may be indicated

Aims. Mid-level constraint designs for total knee arthroplasty (TKA) are intended to reduce coronal plane laxity. Our aims were to compare kinematics and ligament forces of the Zimmer Biomet Persona posterior-stabilized (PS) and mid-level designs in the coronal, sagittal, and axial planes under loads simulating clinical exams of the knee in a cadaver model. Methods. We performed TKA on eight cadaveric knees and loaded them using a robotic manipulator. We tested both PS and mid-level designs under loads simulating clinical exams via applied varus and valgus moments, internal-external (IE) rotation moments, and anteroposterior forces at 0°, 30°, and 90° of flexion. We measured the resulting tibiofemoral angulations and translations. We also quantified the forces carried by the medial and lateral collateral ligaments (MCL/LCL) via serial sectioning of these structures and use of the principle of superposition. Results. Mid-level inserts reduced varus angulations compared to PS inserts by a median of 0.4°, 0.9°, and 1.5° at 0°, 30°, and 90° of flexion, respectively, and reduced valgus angulations by a median of 0.3°, 1.0°, and 1.2° (p ≤ 0.027 for all comparisons). Mid-level inserts reduced net IE rotations by a median of 5.6°, 14.7°, and 17.5° at 0°, 30°, and 90°, respectively (p = 0.012). Mid-level inserts reduced anterior tibial translation only at 90° of flexion by a median of 3.0 millimetres (p = 0.036). With an applied varus moment, the mid-level insert decreased LCL force compared to the PS insert at all three flexion angles that were tested (p ≤ 0.036). In contrast, with a valgus moment the mid-level insert did not reduce MCL force. With an applied internal rotation moment, the mid-level insert decreased LCL force at 30° and 90° by a median of 25.7 N and 31.7 N, respectively (p = 0.017 and p = 0.012). With an external rotation moment, the mid-level insert decreased MCL force at 30° and 90° by a median of 45.7 N and 20.0 N, respectively (p ≤ 0.017 for all comparisons). With an applied anterior load, MCL and LCL forces showed no differences between the two inserts at 30° and 90° of flexion. Conclusion. The mid-level insert used in this study decreased coronal and axial plane laxities compared to the PS insert, but its stabilizing benefit in the sagittal plane was limited. Both mid-level and PS inserts depended on the MCL to resist anterior loads during a simulated clinical exam of anterior laxity. Cite this article: Bone Jt Open 2023;4(6):432–441

Aims. The aims of this study were to determine the proportion of patients with outlier varus or valgus alignment in kinematically aligned total knee arthroplasty (TKA), whether those with outlier varus or valgus alignment have higher forces in the medial or lateral compartments of the knee than those with in-range alignment and whether measurements of the alignment of the limb, knee and components predict compartment forces. Patients and Methods. The intra-operative forces in the medial and lateral compartments were measured with an instrumented tibial insert in 67 patients who underwent a kinematically aligned TKA during passive movement. The mean of the forces at full extension, 45° and 90° of flexion determined the force in the medial and lateral compartments. Measurements of the alignment of the limb and the components included the hip-knee-ankle (HKA) angle, proximal medial tibial angle (PMTA), and distal lateral femoral angle (DLFA). Measurements of the alignment of the knee and the components included the tibiofemoral angle (TFA), tibial component angle (TCA) and femoral component angle (FCA). Alignment was measured on post-operative, non-weight-bearing anteroposterior (AP) scanograms and categorised as varus or valgus outlier or in-range in relation to mechanically aligned criteria. Results. The proportion of patients with outlier varus or valgus alignment was 16%/24% for the HKA angle, 55%/0% for the PMTA, 0%/57% for the DLFA, 25%/12% for the TFA, 100%/0% for the TCA, and 0%/64% for the FCA. In general, the forces in the medial and lateral compartments of those with outlier alignment were not different from those with in-range alignment except for the TFA, in which patients with outlier varus alignment had a mean paradoxical force which was 6 lb higher in the lateral compartment than those with in-range alignment. None of the measurements of alignment of the limb, knee and components predicted the force in the medial or lateral compartment. Conclusion. Although kinematically aligned TKA has a high proportion of varus or valgus outliers using mechanically aligned criteria, the intra-operative forces in the medial and lateral compartments of patients with outlier alignment were comparable with those with in-range alignment, with no evidence of overload of the medial or lateral compartment of the knee. Cite this article: Bone Joint J 2017;99-B:1319–28

We present a series of 30 uncemented total hip replacements performed between June 1985 and January 2002 with a mean follow-up of seven years (5 to 20) in 27 patients who had previously undergone a valgus intertrochanteric osteotomy. No further osteotomy was undertaken to enable hip replacement. We used a number of uncemented modular or monoblock femoral components, acetabular components and bearings. The patients were followed up clinically and radiologically. We report 100% survival of the femoral component. One acetabular component was revised at five years post-implantation for aseptic loosening. We noted cortical hypertrophy around the tip of the monoblock stems in six patients. We believe that modular femoral components should be used when undertaking total hip replacement in patients who have previously undergone valgus femoral osteotomy

Aims. Distal femoral resection in conventional total knee arthroplasty (TKA) utilizes an intramedullary guide to determine coronal alignment, commonly planned for 5° of valgus. However, a standard 5° resection angle may contribute to malalignment in patients with variability in the femoral anatomical and mechanical axis angle. The purpose of the study was to leverage deep learning (DL) to measure the femoral mechanical-anatomical axis angle (FMAA) in a heterogeneous cohort. Methods. Patients with full-limb radiographs from the Osteoarthritis Initiative were included. A DL workflow was created to measure the FMAA and validated against human measurements. To reflect potential intramedullary guide placement during manual TKA, two different FMAAs were calculated either using a line approximating the entire diaphyseal shaft, and a line connecting the apex of the femoral intercondylar sulcus to the centre of the diaphysis. The proportion of FMAAs outside a range of 5.0° (SD 2.0°) was calculated for both definitions, and FMAA was compared using univariate analyses across sex, BMI, knee alignment, and femur length. Results. The algorithm measured 1,078 radiographs at a rate of 12.6 s/image (2,156 unique measurements in 3.8 hours). There was no significant difference or bias between reader and algorithm measurements for the FMAA (p = 0.130 to 0.563). The FMAA was 6.3° (SD 1.0°; 25% outside range of 5.0° (SD 2.0°)) using definition one and 4.6° (SD 1.3°; 13% outside range of 5.0° (SD 2.0°)) using definition two. Differences between males and females were observed using definition two (males more valgus; p < 0.001). Conclusion. We developed a rapid and accurate DL tool to quantify the FMAA. Considerable variation with different measurement approaches for the FMAA supports that patient-specific anatomy and surgeon-dependent technique must be accounted for when correcting for the FMAA using an intramedullary guide. The angle between the mechanical and anatomical axes of the femur fell outside the range of 5.0° (SD 2.0°) for nearly a quarter of patients. Cite this article: Bone Jt Open 2024;5(2):101–108

Aims. This study aimed to evaluate if total knee arthroplasty (TKA) femoral components aligned in either mechanical alignment (MA) or kinematic alignment (KA) are more biomimetic concerning trochlear sulcus orientation and restoration of trochlear height. Methods. Bone surfaces from 1,012 CT scans of non-arthritic femora were segmented using a modelling and analytics system. TKA femoral components (Triathlon; Stryker) were virtually implanted in both MA and KA. Trochlear sulcus orientation was assessed by measuring the distal trochlear sulcus angle (DTSA) in native femora and in KA and MA prosthetic femoral components. Trochlear anatomy restoration was evaluated by measuring the differences in medial, lateral, and sulcus trochlear height between native femora and KA and MA prosthetic femoral components. Results. Femoral components in both MA and KA alignments exhibited a more valgus DTSA compared to native femora. However, DTSA deviation from native was significantly less in KA than in MA (4.8° (SD 2.2°) vs 8.8° (SD 1.8°); p < 0.001). DTSA deviation from native orientation correlated positively with the mechanical lateral distal femoral angle (mLDFA) in KA and negatively in MA (r = 0.53, p < 0.001; r = -0.18, p < 0.001). Medial trochlear height was not restored with either MA or KA, with MA resulting in lower medial trochlear height than KA in the proximal 20% of the trochlea. Lateral and sulcus trochlear height was not restored with either alignment in the proximal 80% of the trochlea. At the terminal arc point, KA replicated sulcus and lateral trochlear height, while MA led to over-restoration. Conclusion. Femoral components aligned in KA demonstrated greater biomimetic qualities than those in MA regarding trochlear sulcus orientation and trochlear height restoration, particularly in valgus femora. Variability across knees was observed, warranting further research to evaluate the clinical implications of these findings. Cite this article: Bone Joint J 2024;106-B(8):817–825

We report a prospective case-controlled study which compared the outcome of knee replacement in seriously deformed and slightly deformed knees. There were 51 knees with varus or valgus deformity greater than 20 degrees matched for age, gender, disease, type of prosthesis and time of operation with a control group in which the alignment of the leg was within 5 degrees of normal. The clinical outcome at a mean 5.5 years was similar in the two groups. Some deformity persisted in 14 patients in the first group, 13 of whom were initially in valgus. These patients had a significantly poorer mean clinical outcome. Lateral dislocation or subluxation of the patella was found in four knees, all of which had had valgus deformity of 30 degrees or more

Aims. Accurate identification of the ankle joint centre is critical for estimating tibial coronal alignment in total knee arthroplasty (TKA). The purpose of the current study was to leverage artificial intelligence (AI) to determine the accuracy and effect of using different radiological anatomical landmarks to quantify mechanical alignment in relation to a traditionally defined radiological ankle centre. Methods. Patients with full-limb radiographs from the Osteoarthritis Initiative were included. A sub-cohort of 250 radiographs were annotated for landmarks relevant to knee alignment and used to train a deep learning (U-Net) workflow for angle calculation on the entire database. The radiological ankle centre was defined as the midpoint of the superior talus edge/tibial plafond. Knee alignment (hip-knee-ankle angle) was compared against 1) midpoint of the most prominent malleoli points, 2) midpoint of the soft-tissue overlying malleoli, and 3) midpoint of the soft-tissue sulcus above the malleoli. Results. A total of 932 bilateral full-limb radiographs (1,864 knees) were measured at a rate of 20.63 seconds/image. The knee alignment using the radiological ankle centre was accurate against ground truth radiologist measurements (inter-class correlation coefficient (ICC) = 0.99 (0.98 to 0.99)). Compared to the radiological ankle centre, the mean midpoint of the malleoli was 2.3 mm (SD 1.3) lateral and 5.2 mm (SD 2.4) distal, shifting alignment by 0.34. o. (SD 2.4. o. ) valgus, whereas the midpoint of the soft-tissue sulcus was 4.69 mm (SD 3.55) lateral and 32.4 mm (SD 12.4) proximal, shifting alignment by 0.65. o. (SD 0.55. o. ) valgus. On the intermalleolar line, measuring a point at 46% (SD 2%) of the intermalleolar width from the medial malleoli (2.38 mm medial adjustment from midpoint) resulted in knee alignment identical to using the radiological ankle centre. Conclusion. The current study leveraged AI to create a consistent and objective model that can estimate patient-specific adjustments necessary for optimal landmark usage in extramedullary and computer-guided navigation for tibial coronal alignment to match radiological planning. Cite this article: Bone Jt Open 2022;3(10):767–776

Aims. The primary aim of this trial was to compare the subsidence of two similar hydroxyapatite-coated titanium femoral components from different manufacturers. Secondary aims were to compare rotational migration (anteversion/retroversion and varus/valgus tilt) and patient-reported outcome measures between both femoral components. Methods. Patients were randomized to receive one of the two femoral components (Avenir or Corail) during their primary total hip arthroplasty between August 2018 and September 2020. Radiostereometric analysis examinations at six, 12, and 24 months were used to assess the migration of each implanted femoral component compared to a baseline assessment. Patient-reported outcome measures were also recorded for these same timepoints. Overall, 50 patients were enrolled (62% male (n = 31), with a mean age of 65.7 years (SD 7.3), and mean BMI of 30.2 kg/m. 2. (SD 5.2)). Results. The two-year subsidence was similar for Avenir (-0.018 mm (95% confidence interval (CI) -0.053 to 0.018) and Corail (0.000 mm (95% CI -0.027 to 0.026; p = 0.428). Both anteversion/retroversion (Avenir 0.139° (95% CI -0.204 to 0.481°); Corail -0.196° (95% CI -0.445 to 0.053°; p = 0.110) and varus/valgus tilt (Avenir -0.024° (95% CI -0.077 to 0.028); Corail -0.049° (95% CI -0.098 to 0.000°; p = 0.473) were not statistically significantly different. After two years, patients reported similar improvements in EuroQol five-dimension five-level health questionnaire (Avenir 0.22 (SD 0.2); Corail 0.22 (SD 0.18); p = 0.965) and other outcomes scores. Patient satisfaction on a five-point Likert scale was also similar between both groups after two years (Avenir 1.38 (SD 0.88); Corail 1.33 (SD 0.57); p = 0.846). Conclusion. The performance of both femoral components was similar in terms of stability and patient outcomes. Cite this article: Bone Joint J 2023;105-B(10):1045–1051

Aims. The aim of this study was to determine the association between knee alignment and the vertical orientation of the femoral neck in relation to the floor. This could be clinically important because changes of femoral neck orientation might alter chondral joint contact zones and joint reaction forces, potentially inducing problems like pain in pre-existing chondral degeneration. Further, the femoral neck orientation influences the ischiofemoral space and a small ischiofemoral distance can lead to impingement. We hypothesized that a valgus knee alignment is associated with a more vertical orientation of the femoral neck in standing position, compared to a varus knee. We further hypothesized that realignment surgery around the knee alters the vertical orientation of the femoral neck. Methods. Long-leg standing radiographs of patients undergoing realignment surgery around the knee were used. The hip-knee-ankle angle (HKA) and the vertical orientation of the femoral neck in relation to the floor were measured, prior to surgery and after osteotomy-site-union. Linear regression was performed to determine the influence of knee alignment on the vertical orientation of the femoral neck. Results. The cohort included 147 patients who underwent knee realignment-surgery. The mean age was 51.5 years (SD 11). Overall, 106 patients underwent a valgisation-osteotomy, while 41 underwent varisation osteotomy. There was a significant association between the orientation of the knee and the coronal neck-orientation. In the varus group, the median orientation of the femoral neck was 46.5° (interquartile range (IQR) 49.7° to 50.0°), while in the valgus group, the orientation was 52.0° (IQR 46.5° to 56.7°; p < 0.001). Linear regression analysis revealed that HKA demonstrated a direct influence on the coronal neck-orientation (β = 0.5 (95% confidence interval (CI) 0.2 to 0.7); p = 0.002). Linear regression also showed that realignment surgery was associated with a significant influence on the change in the coronal femoral neck orientation (β = 5.6 (95% CI 1.5 to 9.8); p = 0.008). Conclusion. Varus or valgus knee alignment is associated with either a more horizontal or a more vertical femoral neck orientation in standing position, respectively. Subsequently, osteotomies around the knee alter the vertical orientation of the femoral neck. These aspects are of importance when planning osteotomies around the knee in order to appreciate the effects on the adjacent hip joint. The concept may be of even more relevance in dysplastic hips. Cite this article: Bone Jt Open 2021;2(12):1057–1061

In distal fibular resection without reconstruction, the stabilising effect of the lateral malleolus is lost. Thus, the ankle may collapse into valgus and may be unstable in varus. Here, we describe a child who underwent successful staged surgical correction of a severe neglected valgus deformity after excision of the distal fibula for a Ewing’s sarcoma

The use of a valgus brace can effectively relieve the symptoms of unicompartmental osteoarthritis of the knee. This study provides an objective measurement of function by analysis of gait symmetry. This was measured in 30 patients on four separate occasions: immediately before and after initial fitting and then again at three months with the brace on and off. All patients reported immediate symptomatic improvement with less pain on walking. After fitting the brace, symmetry indices of stance and the swing phase of gait showed a consistent and immediate improvement at 0 and 3 months, respectively, of 3.92% (p = 0.030) and 3.40% (p = 0.025) in the stance phase and 11.78% (p = 0.020) and 9.58% (p = 0.005) in the swing phase. This was confirmed by a significant improvement at three months in the mean Hospital for Special Surgery (HSS) knee score from 69.9 to 82.0 (p < 0.001). Thus, wearing a valgus brace gives a significant and immediate improvement in the function of patients with unicompartmental osteoarthritis of the knee, as measured by analysis of gait symmetry

Patients with spina bifida cystica commonly have significant disability from a combination of valgus deformity of the ankle and subtalar joints with lateral tibial torsion and plano-abduction deformity of the foot. These deformities can be corrected by a single procedure which combines a supramalleolar tibial osteotomy with a lateral inlay triple fusion. This procedure was carried out on 20 feet in 15 patients and the results were reviewed after an average of three years (range 18 months to 7 years). In 75 per cent of feet the combination of deformities was fully corrected, ulcers and callosities were eliminated in 95 per cent, the use of calipers minimised in 95 per cent, and in all patients the problem of shoe-wrecking was reduced. Complications included recurrent valgus deformity, delayed union of the tibial osteotomy and failure of midtarsal fusion

Aims. The goal was to evaluate tibiofemoral knee joint kinematics during stair descent, by simulating the full stair descent motion in vitro. The knee joint kinematics were evaluated for two types of knee implants: bi-cruciate retaining and bi-cruciate stabilized. It was hypothesized that the bi-cruciate retaining implant better approximates native kinematics. Methods. The in vitro study included 20 specimens which were tested during a full stair descent with physiological muscle forces in a dynamic knee rig. Laxity envelopes were measured by applying external loading conditions in varus/valgus and internal/external direction. Results. The laxity results show that both implants are capable of mimicking the native internal/external-laxity during the controlled lowering phase. The kinematic results show that the bi-cruciate retaining implant tends to approximate the native condition better compared to bi-cruciate stabilized implant. This is valid for the internal/external rotation and the anteroposterior translation during all phases of the stair descent, and for the compression-distraction of the knee joint during swing and controlled lowering phase. Conclusion. The results show a better approximation of the native kinematics by the bi-cruciate retaining knee implant compared to the bi-cruciate stabilized knee implant for internal/external rotation and anteroposterior translation. Whether this will result in better patient outcomes remains to be investigated. Cite this article: Bone Joint Res 2023;12(4):285–293

Müller Weiss disease (MWD) is characterized by lateral navicular necrosis which is associated with a varus alignment of the subtalar joint, varying degrees of arthritis of the talonavicular-cuneiform joints and a paradoxical flatfoot deformity in advanced cases. Although arthrodesis of the hindfoot is commonly used, we present the results of a previously unreported method of treatment using a calcaneus osteotomy incorporating a wedge and lateral translation. Fourteen patients with MWD who were treated with a calcaneus osteotomy were retrospectively reviewed. There were seven females and seven males with an average age of 56 years (range 33–79), and included one grade 5, five grade 4, four grade 3 and four grade 2 patients. Patients had been symptomatic for an average of eleven years (range 1–14), and all underwent initial conservative treatment with an orthotic support that posted the heel into valgus. The primary indication for surgery was a limited but positive response to the use of the orthotic support, and a desire to avoid an arthrodesis of the hindfoot. Results. Patients were followed for an average of three years following the procedure (range 1 – 7 years). Patients rated their pain on a visual analogue pain scale as an average of 8 (range 6–9) prior to surgery and an average of 2 postoperatively (range 0–4). The AOFAS scores improved from a mean of 29 (range 25 – 35) preoperatively to a mean of 79 (range 75–88) postoperatively. Hindfoot range of motion remained and the extent of arthritis of the navicular complex was unchanged. No patient has since required an arthrodesis. Since the majority of MWD patients respond to an orthotic support which changes the load of the hindfoot and forefoot, we believed that patients would respond positively to a calcaneal osteotomy as an alternative treatment

Congenital convex pes valgus (congenital vertical talus) is a rare condition. We reviewed ten feet in seven patients who had had surgical correction. All had been operated on by the senior author (JF) and the same surgical technique was used throughout, incorporating transfer of the tibialis anterior to the neck of the talus. The mean age at surgery was 31 months and the mean follow-up was nine years (6 to 14). All patients completed a questionnaire and had clinical, radiological and photographic evaluation performed by an independent examiner. None had required further surgery. All but one were satisfied with the result, and had no functional limitations. They all wore normal shoes. The mean ankle dorsiflexion was 17° and plantar flexion 21°. The mean arc of subtalar motion was 27°. All radiological parameters measured were within the normal range, although irregularity of the talonavicular joint was common. No avascular necrosis of the body of the talus was seen. We conclude that the medium-term results of this procedure are very satisfactory

Aims. The mid-term results of kinematic alignment (KA) for total knee arthroplasty (TKA) using image derived instrumentation (IDI) have not been reported in detail, and questions remain regarding ligamentous stability and revisions. This paper aims to address the following: 1) what is the distribution of alignment of KA TKAs using IDI; 2) is a TKA alignment category associated with increased risk of failure or poor patient outcomes; 3) does extending limb alignment lead to changes in soft-tissue laxity; and 4) what is the five-year survivorship and outcomes of KA TKA using IDI?. Methods. A prospective, multicentre, trial enrolled 100 patients undergoing KA TKA using IDI, with follow-up to five years. Alignment measures were conducted pre- and postoperatively to assess constitutional alignment and final implant position. Patient-reported outcome measures (PROMs) of pain and function were also included. The Australian Orthopaedic Association National Joint Arthroplasty Registry was used to assess survivorship. Results. The postoperative HKA distribution varied from 9° varus to 11° valgus. All PROMs showed statistical improvements at one year (p < 0.001), with further improvements at five years for Knee Osteoarthritis Outcome Score symptoms (p = 0.041) and Forgotten Joint Score (p = 0.011). Correlation analysis showed no difference (p = 0.610) between the hip-knee-ankle and joint line congruence angle at one and five years. Sub-group analysis showed no difference in PROMs for patients placed within 3° of neutral compared to those placed > 3°. There were no revisions for tibial loosening; however, there were reports of a higher incidence of poor patella tracking and patellofemoral stiffness. Conclusion. PROMs were not impacted by postoperative alignment category. Ligamentous stability was maintained at five years with joint line obliquity. There were no revisions for tibial loosening despite a significant portion of tibiae placed in varus; however, KA executed with IDI resulted in a higher than anticipated rate of patella complications. Cite this article: Bone Jt Open 2022;3(8):656–665

Our study describes the mid-term clinical results of the use of transtrochanteric valgus osteotomy (TVO) for the treatment of osteoarthritis of the hip secondary to acetabular dysplasia. The operation included valgus displacement at the level of the lesser trochanter, and lateral displacement of the greater trochanter by inserting a wedge of bone. We reviewed 70 hips. The mean age of the patients at operation was 44 years (14 to 59). Most (90%) had advanced osteoarthritis. The scores for pain and gait had improved significantly at a mean follow-up of 9.4 years. The rate of survival until an endpoint of a further operation during a follow-up of ten years was 82%. The survival rate was 95% in patients with unilateral involvement who were less than 50 years of age at operation. TVO is a useful form of treatment for advanced osteoarthritis of the hip, particularly in young patients with unilateral disease

There is a specific type of displaced four-part fracture of the proximal humerus which consists of valgus impaction of the head fragment; this deserves special consideration because the rate of avascular necrosis is lower than that of other displaced four-part fractures. Using either closed reduction or limited open reduction and minimal internal fixation, 74% satisfactory results can be achieved in this injury

The relationship between hindfoot deformity and forefoot pressure was assessed in 28 rheumatoid patients who had undergone forefoot reconstruction four years previously. Patients with valgus hindfoot deformities tended to have high forefoot pressures whereas those with a normal hindfoot recorded normal pressures on the dynamic pedobarograph. All patients with residual forefoot pain recorded abnormal forefoot pressures. We believe that orthotic control of hindfoot deformities should be considered for those patients who require forefoot surgery as a combination of surgical and orthotic management may offer the best chance of success

We present a retrospective study of 125 patients with an impacted valgus fracture (B1.1) of the proximal humerus. This fracture rarely occurs in young patients and is much more common in elderly fit subjects. All patients were documented prospectively and followed for one year. None was treated surgically. At one year, 80.6% of the patients had a good or excellent result, the quality of which depended on the age of the patient and the degree of displacement of the fracture. Mean outcome scores based on these two parameters are presented. A comparison with data from other studies suggests that operative fixation of these fractures is not necessary

Aims. It is unknown whether gap laxities measured in robotic arm-assisted total knee arthroplasty (TKA) correlate to load sensor measurements. The aim of this study was to determine whether symmetry of the maximum medial and lateral gaps in extension and flexion was predictive of knee balance in extension and flexion respectively using different maximum thresholds of intercompartmental load difference (ICLD) to define balance. Methods. A prospective cohort study of 165 patients undergoing functionally-aligned TKA was performed (176 TKAs). With trial components in situ, medial and lateral extension and flexion gaps were measured using robotic navigation while applying valgus and varus forces. The ICLD between medial and lateral compartments was measured in extension and flexion with the load sensor. The null hypothesis was that stressed gap symmetry would not correlate directly with sensor-defined soft tissue balance. Results. In TKAs with a stressed medial-lateral gap difference of ≤1 mm, 147 (89%) had an ICLD of ≤15 lb in extension, and 112 (84%) had an ICLD of ≤ 15 lb in flexion; 157 (95%) had an ICLD ≤ 30 lb in extension, and 126 (94%) had an ICLD ≤ 30 lb in flexion; and 165 (100%) had an ICLD ≤ 60 lb in extension, and 133 (99%) had an ICLD ≤ 60 lb in flexion. With a 0 mm difference between the medial and lateral stressed gaps, 103 (91%) of TKA had an ICLD ≤ 15 lb in extension, decreasing to 155 (88%) when the difference between the medial and lateral stressed extension gaps increased to ± 3 mm. In flexion, 47 (77%) had an ICLD ≤ 15 lb with a medial-lateral gap difference of 0 mm, increasing to 147 (84%) at ± 3 mm. Conclusion. This study found a strong relationship between intercompartmental loads and gap symmetry in extension and flexion measured with prostheses in situ. The results suggest that ICLD and medial-lateral gap difference provide similar assessment of soft-tissue balance in robotic arm-assisted TKA. Cite this article: Bone Jt Open 2021;2(11):974–980

Aims. To determine the relationship between articular cartilage status and clinical outcomes after medial opening-wedge high tibial osteotomy (MOHTO) for medial compartmental knee osteoarthritis at intermediate follow-up. Methods. We reviewed 155 patients (155 knees) who underwent MOHTO from January 2008 to December 2016 followed by second-look arthroscopy with a mean 5.3-year follow-up (2.0 to 11.7). Arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system. Patients were divided into two groups based on the presence of normal or nearly normal quality cartilage in the medial femoral condyle: good (second-look arthroscopic) status (ICRS grade I or II; n = 70), and poor (second-look arthroscopic) status (ICRS grade III or IV; n = 85) groups at the time of second-look arthroscopy. Clinical outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-Item Short Form survey. Results. Significant improvements in all clinical outcome categories were found between the preoperative and second-look arthroscopic assessments in both groups (p < 0.001). At the latest follow-up, the mean IKDC and WOMAC scores in the good status group further improved compared with those at the time of second-look arthroscopic surgery (p < 0.001), which was not shown in the poor status group. The mean IKDC (good status, 72.8 (SD 12.5); poor status, 64.7 (SD 12.1); p = 0.002) and mean WOMAC scores (good status, 15.7 (SD 10.8); poor status, 21.8 (SD 13.6); p = 0.004) significantly differed between both groups at the latest follow-up. Moreover, significant correlations were observed between ICRS CRA grades and IKDC scores (negative correlation; p < 0.001) and WOMAC scores (positive correlation; p < 0.001) at the latest follow-up. Good cartilage status was found more frequently in knees with the desired range of 2° to 6° valgus correction than in those with corrections outside this range (p = 0.019). Conclusion. Second-look arthroscopic cartilage status correlated with clinical outcomes after MOHTO at intermediate-term follow-up, despite the relatively small clinical differences between groups. Cite this article: Bone Joint J 2021;103-B(11):1686–1694

A method of triple arthrodesis is described which involves inlay of the subtalar and midtarsal joints. It is applicable to the undeformed and valgus foot as is encountered in poliomyelitis, spasmodic flat foot, cerebral palsy and spina bifida. The operation was successful in controlling deformity and pain. The only significant complication was failure of fusion of the midtarsal joint which occurred in three of eighty-five feet (3-5%)

Nonunion of intertrochanteric fractures is uncommon but its effects are disabling. We describe a modification of the medial displacement and valgus osteotomy of Dimon and Hughston (1967) which we used in seven fractures, six of which united within 16 weeks. Postoperatively, hip function was good. The method provides good initial stability, a source of cancellous bone graft, good postoperative hip abductor function and reliable healing of the nonunion without the need for intraoperative imaging

Aims

To compare time dependent functional improvement for patients with medial, respectively lateral knee osteoarthritis (OA) after treatment with opening wedge osteotomy relieving the pressure on the osteoarthritic part of the knee.

The aim of mechanical alignment in total knee arthroplasty is to align all knees into a fixed neutral position, even though not all knees are the same. As a result, mechanical alignment often alters a patient’s constitutional alignment and joint line obliquity, resulting in soft-tissue imbalance. This annotation provides an overview of how the Coronal Plane Alignment of the Knee (CPAK) classification can be used to predict imbalance with mechanical alignment, and then offers practical guidance for bone balancing, minimizing the need for soft-tissue releases.

Cite this article: Bone Joint J 2024;106-B(6):525–531.

Orthopaedic surgeons are currently faced with an overwhelming number of choices surrounding total knee arthroplasty (TKA), not only with the latest technologies and prostheses, but also fundamental decisions on alignment philosophies. From ‘mechanical’ to ‘adjusted mechanical’ to ‘restricted kinematic’ to ‘unrestricted kinematic’ — and how constitutional alignment relates to these — there is potential for ambiguity when thinking about and discussing such concepts. This annotation summarizes the various alignment strategies currently employed in TKA. It provides a clear framework and consistent language that will assist surgeons to compare confidently and contrast the concepts, while also discussing the latest opinions about alignment in TKA. Finally, it provides suggestions for applying consistent nomenclature to future research, especially as we explore the implications of 3D alignment patterns on patient outcomes.

Cite this article: Bone Joint J 2023;105-B(2):102–108.

Aims

The goal of the current systematic review was to assess the impact of implant placement accuracy on outcomes following total knee arthroplasty (TKA).

The development of genu valgum in a child after a fracture of the upper metaphysis of the tibia with a medial gap is due to the interposition of a flap of fibrous tissue consisting of pes anserinus and periosteum avulsed from the lower fragment. The ensuing biomechanical disturbance induces bowing of the shaft and asymmetrical growth at both ends of the bone. Four cases of established deformity are reported, together with two cases of fresh fracture successfully treated by surgical clearance of the fibrous tissue from the gap.

Preoperative talar valgus deformity increases the technical difficulty of total ankle replacement (TAR) and is associated with an increased failure rate. Deformity of ≥15° has been reported to be a contraindication to arthroplasty. The goal of the present study was to determine whether the operative procedures and clinical outcomes of TAR for treatment of end-stage ankle arthritis were comparable for patients with preoperative talar valgus deformity of ≥15° as compared to those with <15°. We will describe the evolving surgical technique being utilized to tackle these challenging cases. Fifty ankles with preoperative coronal-plane tibiotalar valgus deformity of ≥15° “valgus” group) and 50 ankles with valgus deformity of <15° (“control” group) underwent TAR. The cohorts were similar with respect to demographics and components used. All TARs were performed by a single surgeon. The mean duration of clinical follow-up was 5.5 years (minimum two years). Preoperative and postoperative radiographic measurements of coronal-plane deformity, Ankle Osteoarthritis Scale (AOS) scores and Short Form (SF)-36 scores were prospectively recorded. All ancillary (intraoperative) and secondary procedures, complications and measurements were collected. The AOS pain and disability subscale scores decreased significantly in both groups. The improvement in AOS and SF-36 scores did not differ significantly between the groups at the time of the final follow-up. The valgus group underwent more ancillary procedures during the index surgery (80% vs 26%). Tibio-talar deformity improved significantly toward a normal weight-bearing axis in the valgus group. Secondary postoperative procedures were more common in the valgus group (36%) than the controls (20%). Overall, re-operation was not associated with poorer patient outcome scores. Metal component revision surgery occurred in seven patients (three valgus and four controls). These revisions included two deep infections (2%), one in each group, which were converted to hindfoot fusions. Therefore, 94% of the valgus group retained their original components at final follow-up. Thus far, this is the largest reported study that specifically evaluates TAR with significant preoperative valgus alignment, in addition to having the longest follow-up. Satisfactory midterm results were achieved in patients with valgus mal-alignment of ≥15°. The valgus cohort required more procedures during and after their TAR, as well as receiving more novel techniques to balance their TAR. Whilst longer term studies are needed, valgus coronal-plane alignment of ≥15° should not be considered an absolute contraindication to TAR if the associated deformities are addressed

Abstract. Introduction. Historic MCL reconstruction techniques focused on the superficial MCL to restore valgus stability while overlooking tibial external rotation and the deep MCL. This study assessed the ability of a contemporary medial collateral ligament (MCL) reconstruction and a deep MCL (dMCL) reconstruction to restore rotational and valgus knee stability. Methods. Six pairs fresh-frozen cadaveric knee specimens with intact soft tissue were tested in four states: 1) intact 2) after sMCL and dMCL sectioning, 3) contemporary MCL reconstruction (LaPrade et al), and 4) dMCL reconstruction. In each state, four loading conditions were applied at varying flexion angles: 8Nm valgus torque, 5Nm tibial external rotation torque, 90N anterior drawer, and combined 90N anterior drawer plus 5Nm tibial external rotation torque. Results. Transection of the sMCL and dMCL resulted in increased laxity with valgus torque, external rotation torque, and combined anterior drawer plus external rotation. dMCL reconstruction restored external rotation stability to intact levels throughout all degrees of flexion but did not restore valgus stability at any flexion angle. Contemporary MCL reconstruction restored valgus and external rotation stability at 0° and 20° and valgus stability at 40°. In the combined anterior drawer plus tibial external rotation trial, the dMCL restored stability at 20° and improved stability between 40° and 90° flexion. Conversely, the contemporary MCL reconstruction did not restore stability at any degree of flexion. Conclusion. Deep MCL reconstruction restored rotational stability to the knee throughout range of motion but not valgus stability. The contemporary MCL reconstruction restored stability only near full extension

Abstract. Introduction. Persistent medial laxity increases the risk of failure for ACL reconstruction. To address this, multiple reconstruction techniques have been created. To date, no single strand reconstruction constructs have been able to restore both valgus and rotational stability. In response to this, a novel single strand Short Isometric Construct (SIC) MCL reconstruction was developed. Methods. Eight fresh-frozen cadaveric specimens were tested in three states: 1) intact 2) after sMCL and dMCL transection, and 3) after SIC MCL reconstruction. In each state, four loading conditions were applied at varying flexion angles: 90N anterior drawer, 5Nm tibial external rotation torque, 8Nm valgus torque, and combined 90N anterior drawer plus 5Nm tibial external rotation torque. Results. Transection of the sMCL and dMCL resulted in increased laxity with external rotation torque, valgus torque, and combined anterior drawer plus external rotation. SIC MCL reconstruction restored external rotation and valgus stability to intact levels throughout all degrees of flexion. In the combined test SIC MCL reconstruction also restored stability to intact levels for both anterior distraction and external rotation throughout the range of motion. No significant differences were noted between intact and SIC reconstruction. Conclusion. The single-limb short isometric construct (SIC) MCL reconstruction restored native valgus and rotatory stability to a sMCL- and dMCL-deficient knee in biomechanical testing

Aims. Temporary hemiepiphysiodesis (HED) is applied to children and adolescents to correct angular deformities (ADs) in long bones through guided growth. Traditional Blount staples or two-hole plates are mainly used for this indication. Despite precise surgical techniques and attentive postoperative follow-up, implant-associated complications are frequently described. To address these pitfalls, a flexible staple was developed to combine the advantages of the established implants. This study provides the first results of guided growth using the new implant and compares these with the established two-hole plates and Blount staples. Methods. Between January 2013 and December 2016, 138 patients (22 children, 116 adolescents) with genu valgum or genu varum were treated with 285 flexible staples. The minimum follow-up was 24 months. These results were compared with 98 patients treated with 205 two-hole plates and 92 patients treated with 535 Blount staples. In long-standing anteroposterior radiographs, mechanical axis deviations (MADs) were measured before and during treatment to analyze treatment efficiency. The evaluation of the new flexible staple was performed according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework (Stage 2a). Results. Overall, 79% (109/138) of patients treated with flexible staples achieved sufficient deformity correction. The median treatment duration was 16 months (interquartile range (IQR) 8 to 21). The flexible staples achieved a median MAD correction of 1.2 mm/month/HED site (IQR 0.6 to 2.0) in valgus deformities and 0.6 mm/month/HED site (IQR 0.2 to 1.5) in varus deformities. Wound infections occurred in 1%, haematomas and joint effusions in 4%, and implant-associated complications in 1% of patients treated with flexible staples. Valgus AD were corrected faster using flexible staples than two-hole plates and Blount staples. Furthermore, the median MAD after treatment was lower in varus and valgus AD, fewer implant-associated complications were detected, and reduced implantation times were recorded using flexible staples. Conclusion. The flexible staple seems to be a viable option for guided growth, showing comparable or possibly better results regarding correction speed and reducing implant-associated complications. Further comparative studies are required to substantiate these findings. Cite this article: Bone Joint J 2023;105-B(3):331–340

Abstract. Introduction. Previous research has shown that, notwithstanding ligament healing, properly selected MCL reconstruction can restore normal knee stability after MCL rupture. The hypothesis of this work was that it is possible to restore knee stability (particularly valgus and AMRI) with simplified and/or less-invasive MCL reconstruction methods. Methods. Nine unpaired human knees were cleaned of skin and fat, then digitization screws and optical trackers were attached to the femur and tibia. A Polaris stereo camera measured knee kinematics across 0. o. -100. o. flexion when the knee was unloaded then with 90N anterior-posterior force, 9Nm varus-valgus moment, 5Nm internal-external rotation, and external+anterior (AMRI) loading. The test was conducted for the following knee conditions: intact, injured: transected superficial and deep MCL (sMCL and dMCL), and five reconstructions: (long sMCL, long sMCL+dMCL, dMCL, short sMCL+dMCL, short sMCL), all based on the medial epicondyle isometric point and using 8mm tape as a graft, with long sMCL 60mm below the joint line (anatomical), short sMCL 30mm, dMCL 10mm (anatomical). Results. No significant changes were found in anterior or posterior translation, or varus at any stage. MCL deficiency caused increased valgus, external rotation and AMRI instabilities. All reconstructions restored valgus stability. The isolated long sMCL allowed residual external rotation and AMRI instability, while the short sMCL did stabilise AMRI. Both 2-strand reconstructions (dMCL+sMCL) restored stability. Conclusion. All tested techniques, except long sMCL, restored valgus and AMRI stability of the knee. The single femoral tunnel is satisfactory for both the dMCL and sMCL grafts

Aims. To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty. Methods. We retrospectively reviewed 639 subjects, aged 45 to 79 years, in the Osteoarthritis Initiative (OAI) study, who had symptomatic knees with Kellgren and Lawrence grade 2 to 4. Knees were categorized as neutral, valgus, and varus knees by measuring hip-knee-angles on hip-knee-ankle radiographs. Femorotibial JSW was measured on posteroanterior SF radiographs using a special software. The femorotibial compartment was divided into 16 subregions, and MR-tomographic measurements of cartilage volume, thickness, and subchondral bone area were documented. Linear regression with adjustment for age, sex, body mass index, and Kellgren and Lawrence grade was used. Results. We studied 345 neutral, 87 valgus, and 207 varus knees. Radiological JSW narrowing was significantly (p < 0.01) associated with cartilage volume and thickness in medial femorotibial compartment in neutral (r = 0.78, odds ratio (OR) 2.33) and varus knees (r = 0.86, OR 1.92), and in lateral tibial subregions in valgus knees (r = 0.87, OR 3.71). A significant negative correlation was found between JSW narrowing and area of subchondral bone in external lateral tibial subregion in valgus knees (r = −0.65, p < 0.01) and in external medial tibial subregion in varus knees (r = −0.77, p < 0.01). No statistically significant correlation was found in anterior and posterior subregions. Conclusion. SF radiographs can be potentially used for initial detection of cartilage degeneration as assessed by MRI in medial and lateral but not in anterior or posterior subregions. Cite this article: Bone Joint Res 2021;10(3):173–187

Abstract. Introduction. MCL injuries often occur concurrently with ACL rupture – most noncontact ACL injuries occur in valgus and external rotation (ER) - and conservative MCL treatment leads to increased rate of ACL reconstruction failure. There has been little work developing effective MCL reconstructions. Methods. Cadaveric work measured MCL attachments by digitisation and radiographically, relating them to anatomical landmarks. The isometry of the superficial and deep MCL (sMCL and dMCL) and posterior oblique ligament (POL) was measured using fine sutures led to displacement transducers. Contributions to stability (restraint) were measured in a robotic testing system. Two MCL reconstructions were designed and tested: 3-strand reconstruction (sMCL+dMCL+POL), and 2-strand method (sMCL+dMCL) addressing anteromedial rotatory instability (AMRI). The resulting stability was measured in a kinematics test rig, and compared to the ‘anatomic’ sMCL+POL reconstruction of LaPrade. Results. The sMCL was isometric, centred on the medial epicondyle, and the primary restraint of valgus. The dMCL elongated rapidly in ER, and was the primary restraint of ER near knee extension. The POL slackened rapidly with flexion and only stabilised the knee near extension. With sMCL+dMCL+POL deficiency (‘grade 3’), the 2-strand AM reconstruction restored all stability measures to native, apart from internal rotation. The 3-strand reconstruction restored all stability measures to native. The LaPrade reconstruction did not control ER, lacking a dMCL graft, or valgus in flexion, being anisometric. Conclusions. This work has revealed the importance of the dMCL in stabilising AMRI as part of anatomical MCL reconstruction, with the sMCL restraining valgus

Introduction. Angular deformities of the distal femur can be corrected by opening, closing and neutral wedge techniques. Opening wedge (OW) and closing wedge (CW) are popular and well described in the literature. CW and OW techniques lead to leg length difference whereas the advantage of neutral wedge (NW) technique has several unique advantages. NW technique maintains limb length, wedge taken from the closing side is utilised on the opening side and since the angular correction is only half of the measured wedge on either side, translation of distal fragment is minimum. Leg lengths are not altered with this technique hence a useful technique in large deformities. We found no reports of clinical outcomes using NW technique. We present a technique of performing external fixator assisted NW correction of large valgus and varus deformities of distal femur and dual plating and discuss the results. Materials & Methods. We have treated 20 (22 limbs – 2 patients requiring staged bilateral corrections) patients for distal femoral varus and valgus deformities with CWDFO between 2019 and 2022. Out of these 4 patients (5 limbs) requiring large corrections of distal femoral angular deformities were treated with Neutral Wedge (NW) technique. 3 patients (four limbs) had distal femoral valgus deformity and one distal femoral varus deformity. Indication for NW technique is an angular deformity (varus or valgus of distal femur) requiring > 12 mm opening/closing wedge correction. We approached the closing side first and marked out the half of the calculated wedge with K – wires in a uniplanar fashion. Then an external fixator with two Schanz screws is applied on the opposite side, inserting the distal screw parallel to the articular surface and the proximal screw 6–7 cm proximal to the first pin and at right angles to the femoral shaft mechanical axis. Then the measured wedge is removed and carefully saved. External fixator is now used to close the wedge and over correct, creating an appropriate opening wedge on the opposite side. A Tomofix (Depuoy Synthes) plate is applied on the closing side with two screws proximal to osteotomy and two distally (to be completed later). Next the osteotomy on the opposite side is exposed, the graft is inserted. mLDFA is measured under image intensifier to confirm satisfactory correction. Closing wedge side fixation is then completed followed by fixation of opposite side with a Tomofix or a locking plate. Results. 3 patients (4 limbs) had genu valgum due to constitutional causes and one was a case of distal femoral varus from a fracture. Preoperative mLDFA ranged from 70–75° and in one case of varus deformity it was 103°. We achieved satisfactory correction of mLDFA in (85–90°) in 4 limbs and one measured 91°. Femoral length was not altered. JLCA was not affected post correction. Patients were allowed to weight bear for transfers for the first six weeks and full weight bearing was allowed at six weeks with crutches until healing of osteotomy. All osteotomies healed at 16–18 weeks (average 16.8 weeks). Patients regained full range of movement. We routinely recommend removal of metal work to facilitate future knee replacement if one is needed. Follow up ranged from 4 months to 2 yrs. Irritation from metal work was noted in 2 patients and resolved after removing the plates at 9 months post-surgery. Conclusions. NWDFO is a good option for large corrections. We describe a technique that facilitates accurate correction of deformity in these complex cases. Osteotomy heals predictably with uniplanar osteotomy and dual plate fixation. Metal work might cause irritation like other osteotomy and plating techniques in this location

Abstract. Introduction. Double-level knee osteotomy (DLO) is a challenging procedure that requires precision in preoperative planning and intraoperative execution to achieve the desired correction. It is indicated in cases of severe varus or valgus deformities where a single-level osteotomy would yield significantly tilted joint line obliquity (JLO). Methods. A single-centre, retrospective analysis of prospectively collected data for 26 patients, who underwent DLO by PSCGs for valgus malaligned knees. Post-operative alignment was evaluated and the delta for different lower limb alignment parameters were calculated; HKA, MPTA, and LDFA. At the two-year follow-up, changes in KOOS sub-scores, UCLA scores, lower limb discrepancy, and mean time to return to work and sport were recorded. All intraoperative and postoperative complications were recorded. Results. The postoperative mean ΔHKA was 0.9 ± 0.9°, the mean ΔMPTA was 0.7 ± 0.7°, and the mean ΔLDFA was 0.7 ± 0.8° (all values with p > 0.05). All KOOS subscores’ mean values were improved to an extent two-fold superior to the reported MCID (all with p < 0.0001). There was a significant increase in the UCLA score at the final follow-up (5.4 ± 1.5 preoperatively versus 7.7 ± 1.4, p < 0.01). The mean time to return to sport and work was 4.7 ± 1.1 and 4.3 ± 2.1 months, respectively. There was an improvement in Lower-limb discrepancy preoperative (LLD = 1.3+/−2cm) to postoperative measures (LLD= 0.3 +/− 0.4 cm) p=0.02. Conclusion. DLO is effective and safe in achieving accurate correction in bifocal valgus malaligned knees with maintained lower limb length and low complication rate with no compromise of JLO

Introduction. Hip dysplasia is the most common congenital deformity of the musculoskeletal system. This is a pathology that brings the hip joint from subluxation to dislocation. Frequency of hip dysplasia − 16 children per 1000 newborns. Materials and Methods. Diagnostic methods of research are X-ray inspection which is necessarily carried out at internal rotation (rotation) of an extremity as lateral rotation of a hip on the radiograph always increases an angle of a valgus deviation of a neck. Surgical treatment is performed in the subclavian area of the femur. An external fixation device is applied and a corrective corticotomy is performed, and valgus deformity and anteversion are eliminated. The duration of treatment is 2.5–3 months. Results. Frequency of hip dysplasia − 16 children per 1000 newborns. We perform about 30 operations a year, including 60% girls and 40% boys. In addition, valgus deformity can be traced -. - in cerebral palsy. - after polio. - at progressing muscular dystrophies. - tumor in the area of the epiphyseal cartilage. At insufficient stability in a hip joint at insufficiently expressed roof of an acetabulum of rotational deformation of a neck of a hip, for prevention of a coxarthrosis and normalization of a ratio of articular ends operation detorsion-varying subvertebral corticotomy of a femur is shown. Conclusions. The operation is minimally invasive, with accesses of 5–6 mm, anatomical and topographical features are taken into account, which will eliminate damage to tissues, nerve trunks and the circulatory system

Aims. Total knee arthroplasty (TKA) may provoke ankle symptoms. The aim of this study was to validate the impact of the preoperative mechanical tibiofemoral angle (mTFA), the talar tilt (TT) on ankle symptoms after TKA, and assess changes in the range of motion (ROM) of the subtalar joint, foot posture, and ankle laxity. Methods. Patients who underwent TKA from September 2020 to September 2021 were prospectively included. Inclusion criteria were primary end-stage osteoarthritis (Kellgren-Lawrence stage IV) of the knee. Exclusion criteria were missed follow-up visit, post-traumatic pathologies of the foot, and neurological disorders. Radiological angles measured included the mTFA, hindfoot alignment view angle, and TT. The Foot Function Index (FFI) score was assessed. Gait analyses were conducted to measure mediolateral changes of the gait line and ankle laxity was tested using an ankle arthrometer. All parameters were acquired one week pre- and three months postoperatively. Results. A total of 69 patients (varus n = 45; valgus n = 24) underwent TKA and completed the postoperative follow-up visit. Of these, 16 patients (23.2%) reported the onset or progression of ankle symptoms. Varus patients with increased ankle symptoms after TKA had a significantly higher pre- and postoperative TT. Valgus patients with ankle symptoms after TKA showed a pathologically lateralized gait line which could not be corrected through TKA. Patients who reported increased ankle pain neither had a decreased ROM of the subtalar joint nor increased ankle laxity following TKA. The preoperative mTFA did not correlate with the postoperative FFI (r = 0.037; p = 0.759). Conclusion. Approximately one-quarter of the patients developed ankle pain after TKA. If patients complain about ankle symptoms after TKA, standing radiographs of the ankle and a gait analysis could help in detecting a malaligned TT or a pathological gait. Cite this article: Bone Joint J 2023;105-B(11):1159–1167

Aims. To systematically review the efficacy of split tendon transfer surgery on gait-related outcomes for children and adolescents with cerebral palsy (CP) and spastic equinovarus foot deformity. Methods. Five databases (CENTRAL, CINAHL, PubMed, Embase, Web of Science) were systematically screened for studies investigating split tibialis anterior or split tibialis posterior tendon transfer for spastic equinovarus foot deformity, with gait-related outcomes (published pre-September 2022). Study quality and evidence were assessed using the Methodological Index for Non-Randomized Studies, the Risk of Bias In Non-Randomized Studies of Interventions, and the Grading of Recommendations Assessment, Development and Evaluation. Results. Overall, 17 studies (566 feet) were included: 13 studies used clinical grading criteria to report a postoperative ‘success’ of 87% (75% to 100%), 14 reported on orthotic use with 88% reduced postoperative use, and one study reported on ankle kinematics improvements. Ten studies reported post-surgical complications at a rate of 11/390 feet (2.8%), but 84 feet (14.8%) had recurrent varus (68 feet, 12%) or occurrence of valgus (16 feet, 2.8%). Only one study included a patient-reported outcome measure (pain). Conclusion. Split tendon transfers are an effective treatment for children and youth with CP and spastic equinovarus foot deformities. Clinical data presented can be used for future study designs; a more standardized functional and patient-focused approach to evaluating outcomes of surgical intervention of gait may be warranted. Cite this article: Bone Jt Open 2023;4(5):283–298

Abstract. INTRODUCTION. Fracture neck of femur is aptly called as “the fracture of necessity” owing to the various factors responsible for its non-union. Pauwel's inter-trochantric valgus osteotomy is a useful approach to deal with such fractures. AIM. The aim of this study is to evaluate the functional outcome of valgus osteotomy in treatment of neglected and non-union fracture neck of femur using Harris Hip Scoring system (HHS). MATERIAL AND METHODS. This observational study included 25 patients of the age between 25 years and 50 years with more than 3 weeks since injury and the patients with failed primary fixation. Valgus osteotomy using120° double angled blade plate was done. The patients were followed up till one year. The patients' functional outcome was evaluated with pre-operative and post-operative Harris Hip Score (HHS) at 6 months and one year. RESULTS. Outcome was excellent in 14 patients (HHS>90), good in 8 patients (HHS between 80–90) and fair in one patient (HHS=75.6). Two patients ended up in non-union with blade cut out. The mean HHS at the end of one year was 89.18 + 7.822. The mean change in HHS values pre-operatively and one year post-operatively came out to be 69.58 + 20.032. CONCLUSION. We conclude that for the patients under 50 years of age with neglected fracture of the femoral neck, the Pauwel's osteotomy produces many good results

Introduction. Fibula contributes to weight bearing and serves as a lateral buttress to the talus. Fibular shortening leads to ankle valgus, distal tibial epiphyseal wedging and ankle instability. Trauma, infection and skeletal dyplasias are the common causes of fibular shortening in children. Aim was to review this cohort who underwent fibular lengthening and ankle reconstruction. Materials and Methods. Retrospective review from a prospective database of clinical and radiographic data of all children who underwent fibular lengthening for correction of ankle valgus. Distraction osteogenesis with external fixator was performed for all cases. Results. Eight children with 10 fibulae (average age: 10 years) were followed up for an average of 75.6 months. In older children, corrective tibial osteotomy was performed in addition to fibular lengthening. TSF frame mounted with mini-rail fixator was used in seven children who required adjuvant tibial correction and mini-rail was used for bilateral fibular lengthening in one. Remodelling of the wedged distal tibial epiphysis was noted in 75%. Talar tilt and mLDTA improved in 66.7% and fibular station in 85.7% limbs. Seven year old girl required re-lengthening. Two children developed fibular non-union. Proximal fibular migration was observed in one child, in whom the tibial wire did not engage the fibula. Conclusions. Restoration of tibial mechanical axis and lateral talar buttress is necessary to correct ankle valgus. Stabilisation of fibula to the tibia is prudent during distraction. Younger children may require re-lengthening. Remodelling of the triangular tibial epiphysis can be achieved when done early

Accurate evaluation of lower limb coronal alignment is essential for effective pre-operative planning of knee arthroplasty. Weightbearing hip-knee-ankle (HKA) radiographs are considered the gold standard. Mako SmartRobotics uses CT-based navigation to provide intra-operative data on lower limb coronal alignment during robotic assisted knee arthroplasty. This study aimed to compare the correlation between the two methods in assessing coronal plane alignment. Patients undergoing Mako partial (PKA) or total knee arthroplasty (TKA) were identified from our hospital database. The hospital PACS system was used to measure pre-operative coronal plane alignment on HKA radiographs. This data was correlated to the intraoperative deformity assessment during Mako PKA and TKA surgery. 443 consecutive Mako knee arthroplasties were performed between November 2019 and December 2021. Weightbearing HKA radiographs were done in 56% of cases. Data for intraoperative coronal plane alignment was available for 414 patients. 378 knees were aligned in varus, and 36 in valgus. Mean varus deformity was 7.46° (SD 3.89) on HKA vs 7.13° (SD 3.56) on Mako intraoperative assessment, with a moderate correlation (R= 0.50, p<0.0001). Intraoperative varus deformity of 0-4° correlated to HKA measured varus (within 3°) in 60% of cases, compared to 28% for 5-9°, 17% for 10-14°, and in no cases with >15° deformity. Mean valgus deformity was 6.44° (SD 4.68) on HKA vs 4.75° (SD 3.79) for Mako, with poor correlation (R=0.18, p=0.38). In this series, the correlation between weightbearing HKA radiographs and intraoperative alignment assessment using Mako SmartRobotics appears to be poor, with greater deformities having poorer correlation

3D accurate measurements of the skeletal structures of the foot, in physiological and impaired subjects, are now possible using Cone-Beam CT (CBCT) under real-world loading conditions. In detail, this feature allows a more realistic representation of the relative bone-bone interactions of the foot as they occur under patient-specific body weight conditions. In this context, varus/valgus of the hindfoot under altered conditions or the thinning of plantar tissues that occurs with advancing age are among the most complex and interesting to represent, and numerous measurement proposals have been proposed. This study aims to analyze and compare these measurements from CBCT in weight-bearing scans in a clinical population. Sixteen feet of diabetic patients and ten feet with severe adult flatfoot acquired before/after corrective surgery underwent CBCT scans (Carestream, USA) while standing on the leg of interest. Corresponding 3D shapes of each bone of the shank and hindfoot were reconstructed (Materialise, Belgium). Six different techniques found in the literature were used to calculate the varus/valgus deformity, i.e., the inclination of the hindfoot in the frontal plane of the shank, and the distance between the ground and the metatarsal heads was calculated along with different solutions for the identification of possible calcifications. Starting with an accurate 3D reconstruction of the skeletal structures of the foot, a wide range of measurements representing the same angle of hindfoot alignment were found, some of them very different from each other. Interesting correlations were found between metatarsal height and subject age, significant in diabetic feet for the fourth and fifth metatarsal bones. Finally, CBCT allows 3D assessment of foot deformities under loaded conditions. The observed traditional measurement differences and new measurement solutions suggest that clinicians should consider carefully the anatomical and functional concepts underlying measurement techniques when drawing clinical and surgical conclusions

Total hip arthroplasty (THA) for congenital hip dysplasia (CDH) presents a challenge. In high-grade CDH, key surgical targets include cup placement in the anatomical position and leg length equality. Lengthening of more than 4 cm is associated with sciatic nerve injury, therefore shortening osteotomies are necessary. We present our experience of different shortening osteotomies including advantages and disadvantages of each technique. 89 hips, in 61 pts (28 bilateral cases), for high CDH were performed by a single surgeon from 1997 to 2022. 67 patients were female and 22 were male. Age ranged from 38 to 68 yrs. In all patients 5–8cm of leg length discrepancy (LLD) was present, requiring shortening femoral osteotomy. 12 patients underwent sequential proximal femoral resection with trochanteric osteotomy, 46 subtrochanteric, 6 midshaft, and 25 distal femoral osteotomies with simultaneous valgus correction were performed. All acetabular prostheses were placed in the true anatomical position. We used uncemented high porosity cups. Patients were followed up for a minimum of 12 months. All osteotomies healed uneventfully except 3 non-unions of the greater trochanter in the proximal femur resection group. No femoral shaft fractures in proximally based osteotomies. No significant LLD compared to the unaffected or reconstructed side. 2 patients suffered 3 and 5 degrees malrotation of the femur in the oblique sub-trochanteric group. 3 patients suffered transient sciatic nerve palsies. Shortening femoral osteotomies in the treatment of DDH are necessary to avoid injury to the sciatic nerve. In our series, we found transverse subtrochanteric osteotomies to be the most technically efficient, versatile and predictable in their clinical outcome, due to the ability to correct rotation and preserve the metaphyseal bone integrity, allowing for better initial stem stability. Distal femoral osteotomies allowed for controllable correction of valgus knee deformity

Introduction. Coronal malalignment and leg length discrepancies (LLD) are frequently associated. Temporary hemiepiphysiodesis (tHED) is commonly employed for the correction of limb malalignment in skeletally immature patients. For treatment of LLD greater than 2 cm, lengthening with intramedullary legnthening nails is a safe and reliable technique. However, the combined application of these approaches in skeletally immature patients has not yet been investigated. Materials & Methods. Retrospective radiological and clinical analysis of 25 patients (14 females, 11 males) who underwent intramedullary femoral lengthening with an antegrade PRECICE® lengthening nail as well as tHED of the distal femur and / or proximal tibia between 2014 and 2019. tHED was conducted by implantation of flexible staples (FlexTack™) either prior (n = 11), simultaneously (n = 10), or subsequently (n = 4) to femoral lengthening. The mean follow-up period was 3.7 years (±1.4). Results. The median initial LLD was 39.0 mm (35.0–45.0). 21 patients (84%) presented valgus and 4 (16%) showed varus malalignment. Leg length equalization was achieved in 13 patients at skeletal maturity (62%). The median LLD of patients with a residual LLD > 10 mm was 15.5 mm (12.8–21.8). Limb realignment was obtained in nine of seventeen skeletally mature patients (53%) in the valgus group, and in one of four patients (25%) in the varus group. Conclusions. The combination of antegrade femoral lengthening and tHED can efficiently correct LLD and coronal limb malalignment in skeletally immature patients. Nevertheless, achieving limb length equalization and realignment may render difficult in cases of severe LLD and angular deformity. Furthermore, the reported techniques ought to be thoroughly planned and executed and require regular clinical and radiological examinations until skeletal maturity to avoid - or timely detect and manage - adverse events such as overcorrection and rebound of deformity

Periprosthetic femoral fractures are increasingly seen in recent years, adding considerable burden to the National Health Service. These require complex revision or fixation and prolonged post-operative care, with significant morbidity with associated costs. The purpose of this study was to assess whether the size of femoral cement mantle is associated with periprosthetic femoral fractures (PPF). This retrospective study was carried out on a cohort of 49 patients (Fracture Group - FG) who previously had a revision procedure following a proximal PPF between 2010 and 2021. Inclusion criteria – all primary cemented total hip replacements (THR). Exclusion criteria – complex primary THR, any implant malposition that required early revision surgery or any pre-fracture stem loosening. The antero-posterior (AP) radiographs from this cohort of patients were assessed and compared to an age, sex, time since THR-matched control group of 49 patients without PPF (Control Group - CG). Distal cement mantle area (DCMA) was calculated on an AP radiograph of hip; the position of the femoral stem tip prior to fracture was also recorded: valgus, varus or central. Limitations: AP radiographs only. Statistical analyses were performed using Microsoft® Excel. Chi-square test demonstrated statistically significant difference in DCMA between FG and CG. DCMA of 700 to 900 mm² appeared to be protective when compared to DCMA of 0 to 300 mm². Also, a valgus position observed in 23% in FG Vs 4 % in CG increased the risk, with a smaller area of DCMA. This study demonstrates and recommends that a size of 700 – 900 mm² of the DCMA is protective against periprosthetic fractures, which are further influenced by the positioning of the distal stem tip. This could be due to the gradual decrease in the stiffness gradient from proximal to distal around the stem tip than steep changes, thereby decreasing possibility of a stress riser just distal to the cement mantle or restrictor. Further biomechanical research specific to this finding may be helpful to validate the observation, progressing to suggest a safe standardised surgical technique

Lateral approach open calcaneal osteotomy is the described gold standard procedure in the management of hindfoot deformity. With development of minimally invasive surgery, a MIS approach has been described, citing fewer wound complications and lower risk of sural nerve injury. This audit compares MIS to the traditional procedure. A retrospective review of all patients undergoing calcaneal osteotomy in Northumbria Trust in the past 5 years was performed. A total of 105 osteotomies were performed in 97 patients; 28 (13M:15F) in MIS group and 77 (40M:37F) had an open approach. The average age was 52.1 (range 16–83) for MIS and 51.5 (range 18–83) in the open group. All patients were followed up for development of wound complication, nerve injury and fusion rate. Wound complications were similar (10.7% in MIS group vs 10.3% in Open group) with no significant difference (p=0.48). Patients were treated for infection in 3(3.8%) cases in the open group and 2(7.1%) in the MIS group. This difference was not significant (p=0.43). 4 (14.3%) patients in the MIS group had evidence of sural nerve dysfunction post-operatively (managed expectantly), compared to 12(15.5%) patients in the open group (p=0.44). Of these, 2 went on to undergo neuroma exploration. There was no difference in nerve dysfunction in varus or valgus correction. Mean translation in the open group was measured as 7.3mm(SD=1.91;3 to 13mm) and 7.5mm(SD=1.25;5 to 10mm) in the MIS group. Translation was similar in varus or valgus correction. Non-union occurred in 2 patients in the MIS group and none in the open group (p= 0.06). MIS calcaneal osteotomy is a safe technique, that works as effectively as osteotomy performed through an open approach. There were lower rates of nerve injury, wound complication and infection, but this was not significantly different comparing groups. There was a higher risk of non-union in MIS technique

This study aims to create a novel computational workflow for frontal plane laxity evaluation which combines a rigid body knee joint model with a non-linear implicit finite-element model wherein collateral ligaments are anisotropically modelled using subject-specific, experimentally calibrated Holzpfel-Gasser-Ogden (HGO) models. The framework was developed based on CT and MRI data of three cadaveric post-TKA knees. Bones were segmented from CT-scans and modelled as rigid bodies in a multibody dynamics simulation software (MSC Adams/view, MSC Software, USA). Medial collateral and lateral collateral ligaments were segmented based on MRI-scans and are modelled as finite elements using the HGO model in Abaqus (Simulia, USA). All specimens were submitted varus/valgus loading (0-10Nm) while being rigidly fixed on a testing bench to prevent knee flexion. In subsequent computer simulations of the experimental testing, rigid bodies kinematics and the associated soft-tissue force response were computed at each time step. Ligament properties were optimised using a gradient descent approach by minimising the error between the experimental and simulation-based kinematic response to the applied varus/valgus loads. For comparison, a second model was defined wherein collateral ligaments were modelled as nonlinear no-compression spring elements using the Blankevoort formulation. Models with subject-specific, experimentally calibrated HGO representations of the collateral ligaments demonstrated smaller root mean square errors in terms of kinematics (0.7900° +/− 0.4081°) than models integrating a Blankevoort representation (1.4704° +/− 0.8007°). A novel computational workflow integrating subject-specific, experimentally calibrated HGO predicted post-TKA frontal-plane knee joint laxity with clinically applicable accuracy. Generally, errors in terms of tibial rotation were higher and might be further reduced by increasing the interaction nodes between the rigid body model and the finite element software. Future work should investigate the accuracy of resulting models for simulating unseen activities of daily living

Proximal humeral shaft fractures are commonly treated with long straight locking plates endangering the radial nerve distally. The aim of this study was to investigate the biomechanical competence in a human cadaveric bone model of 90°-helical PHILOS plates versus conventional straight PHILOS plates in proximal third comminuted humeral shaft fractures. Eight pairs of humeral cadaveric humeri were instrumented using either a long 90°-helical plate (group1) or a straight long PHILOS plate (group2). An unstable proximal humeral shaft fracture was simulated by means of an osteotomy maintaining a gap of 5cm. All specimens were tested under quasi-static loading in axial compression, internal and external rotation as well as bending in 4 directions. Subsequently, progressively increasing internal rotational loading until failure was applied and interfragmentary movements were monitored by means of optical motion tracking. Flexion/extension deformation (°) in group1 was (2.00±1.77) and (0.88±1.12) in group2, p=0.003. Varus/valgus deformation (°) was (6.14±1.58) in group1 and (6.16±0.73) in group2, p=0.976. Shear (mm) and displacement (°) under torsional load were (1.40±0.63 and 8.96±0.46) in group1 and (1.12±0.61 and 9.02±0.48) in group2, p≥0.390. However, during cyclic testing shear and torsional displacements and torsion were both significantly higher in group 1, p≤0.038. Cycles to catastrophic failure were (9960±1967) in group1 and (9234±1566) in group2, p=0.24. Although 90°-helical plating was associated with improved resistance against varus/valgus deformation, it demonstrated lower resistance to flexion/extension and internal rotation as well as higher flexion/extension, torsional and shear movements compared to straight plates. From a biomechanical perspective, 90°-helical plates performed inferior compared to straight plates and alternative helical plate designs with lower twist should be investigated in future paired cadaveric studies

Aims. The aim of this retrospective cohort study was to assess and investigate the safety and efficacy of using a distal tibial osteotomy compared to proximal osteotomy for limb lengthening in children. Methods. In this study, there were 59 consecutive tibial lengthening and deformity corrections in 57 children using a circular frame. All were performed or supervised by the senior author between January 2013 and June 2019. A total of 25 who underwent a distal tibial osteotomy were analyzed and compared to a group of 34 who had a standard proximal tibial osteotomy. For each patient, the primary diagnosis, time in frame, complications, and lengthening achieved were recorded. From these data, the frame index was calculated (days/cm) and analyzed. Results. All patients ended their treatment with successful lengthening and deformity correction. The frame index for proximal versus distal osteotomies showed no significant difference, with a mean 48.5 days/cm (30 to 85) and 48.9 days/cm (28 to 81), respectively (p = 0.896). In the proximal osteotomy group, two patients suffered complications (one refracture after frame removal and one failure of regenerate maturation with subsequent valgus deformity) compared to zero in the distal osteotomy group. Two patients in each group sustained obstacles that required intervention (one necessitated guided growth, one fibula lengthening, and two required change of wires). There was a similar number of problems (pin-site infections) in each group. Conclusion. Our data show that distal tibial osteotomies can be safely employed in limb lengthening for children using a circular frame, which has implications in planning a surgical strategy; for example, when treating a tibia with shortening and distal deformity, a second osteotomy for proximal lengthening is not required. Cite this article: Bone Joint J 2022;104-B(11):1273–1278

Constrained implants with intra-medullary fixation are expedient for complex TKA. Constraint is associated with loosening, but can correction of deformity mitigate risk of loosening?. Primary TKA's with a non-linked constrained prosthesis from 2010-2018 were identified. Indications were ligamentous instability or intra-medullary fixation to bypass stress risers. All included fully cemented 30mm stem extensions on tibia and femur. If soft tissue stability was achieved, a posterior stabilized (PS) tibial insert was selected. Pre and post TKA full length radiographs showed. i. hip-knee-ankle angles (HKAA). ii. Kennedy Zone (KZ) where hip to ankle vector crosses knee joint. 77 TKA's in 68 patients, average age 69.3 years (41-89.5) with OA (65%) post-trauma (24.5%) and inflammatory arthropathy (10.5%). Pre-op radiographs (62 knees) showed varus in 37.0%. (HKAA: 4. o. -29. o. ), valgus in 59.6% (HKAA range 8. o. -41. o. ) and 2 knees in neutral. 13 cases deceased within 2 years were excluded. Six with 2 year follow up pending have not been revised. Mean follow-up is 6.1 yrs (2.4-11.9yrs). Long post-op radiographs showed 34 (57.6%) in central KZ (HKKA 180. o. +/- 2. o. ). . Thirteen (22.0%) were in mechanical varus (HKAA 3. o. -15. o. ) and 12 (20.3%) in mechanical valgus: HKAA (171. o. -178. o. ). Three failed with infection; 2 after ORIF and one with BMI>50. The greatest post op varus suffered peri-prosthetic fracture. There was no aseptic loosening or instability. Only full-length radiographs accurately measure alignment and very few similar studies exist. No cases failed by loosening or instability, but PPF followed persistent malalignment. Infection complicated prior ORIF and elevated BMI. This does not endorse indiscriminate use of mechanically constrained knee prostheses. Lower demand patients with complex arthropathy, especially severe deformity, benefit from fully cemented, non-linked constrained prostheses, with intra-medullary fixation. Hinges are not necessarily indicated, and rotational constraint does not lead to loosening

An increasingly used treatment for end-stage ankle osteoarthritis is total ankle replacement (TAR). However, implant loosening and subsidence are commonly reported complications, leading to relatively high TAR failure rates. Malalignment of the TAR has often been postulated as the main reason for the high incidence of these complications. It remains unclear to what extent malalignment of the TAR affects the stresses at the bone-implant interface. Therefore, this study aims to elucidate the effect of TAR malalignment on the contact stresses on the bone-implant interface, thereby gaining more understanding of the potential role of malalignment in TAR failure. FE models of the neutrally aligned as well as malaligned CCI Evolution TAR implant (Van Straten Medical) were developed. Separate models were developed for the tibial and talar segment, with the TAR components in neutral alignment and 5° and 10° varus, valgus, anterior and posterior malalignment, resulting in a total of 9 differently aligned TAR models. Loading conditions of the terminal stance phase of the gait cycle, when the force on the ankle joint is highest (5.2x body weight), were applied. Peak and mean contact pressure and shear stress at the bone-implant interface were analyzed. Also, stress distributions on the bone-implant interface were visualized. In the neutrally aligned tibial and talar TAR models, peak contact pressures of respectively 98.4 MPa and 68.2 MPa, and shear stresses of respectively 49.3 MPa and 39.0 MPa were found. TAR malalignment increases peak contact pressure and shear stress on the bone-implant interface. A maximum peak contact pressure of 177 MPa was found for the 10° valgus malaligned tibial component and the highest shear stress found was 98.5 MPa for the 10° posterior malaligned talar model. Upon TAR malalignment contact stresses increase substantially, suggesting that proper orientation of the TAR is needed to minimize peak stresses on the bone-implant interface. This is in line with previous studies, which state that malalignment considerably increases bone strains, micromotion, and internal TAR contact pressures, which might increase the risk of TAR failure. Further research is needed to investigate the relationship between increased contact stresses at the bone-implant interface and TAR failure

Aims. Accurate skeletal age and final adult height prediction methods in paediatric orthopaedics are crucial for determining optimal timing of growth-guiding interventions and minimizing complications in treatments of various conditions. This study aimed to evaluate the accuracy of final adult height predictions using the central peak height (CPH) method with long leg X-rays and four different multiplier tables. Methods. This study included 31 patients who underwent temporary hemiepiphysiodesis for varus or valgus deformity of the leg between 2014 and 2020. The skeletal age at surgical intervention was evaluated using the CPH method with long leg radiographs. The true final adult height (FH. TRUE. ) was determined when the growth plates were closed. The final height prediction accuracy of four different multiplier tables (1. Bayley and Pinneau; 2. Paley et al; 3. Sanders – Greulich and Pyle (SGP); and 4. Sanders – peak height velocity (PHV)) was then compared using either skeletal age or chronological age. Results. All final adult height predictions overestimated the FH. TRUE. , with the SGP multiplier table having the lowest overestimation and lowest absolute deviation when using both chronological age and skeletal age. There were no significant differences in final height prediction accuracy between using skeletal age and chronological age with PHV (p = 0.652) or SGP multiplier tables (p = 0.969). Adult height predictions with chronological age and SGP (r = 0.769; p ≤ 0.001), as well as chronological age and PHV (r = 0.822; p ≤ 0.001), showed higher correlations with FH. TRUE. than predictions with skeletal age and SGP (r = 0.657; p ≤ 0.001) or skeletal age and PHV (r = 0.707; p ≤ 0.001). Conclusion. There was no significant improvement in adult height prediction accuracy when using the CPH method compared to chronological age alone. The study concludes that there is no advantage in routinely using the CPH method for skeletal age determination over the simple use of chronological age. The findings highlight the need for more accurate methods to predict final adult height in contemporary patient populations. Cite this article: Bone Jt Open 2023;4(10):750–757

Aims. Surgeons commonly resect additional distal femur during primary total knee arthroplasty (TKA) to correct a flexion contracture, which leads to femoral joint line elevation. There is a paucity of data describing the effect of joint line elevation on mid-flexion stability and knee kinematics. Thus, the goal of this study was to quantify the effect of joint line elevation on mid-flexion laxity. Methods. Six computational knee models with cadaver-specific capsular and collateral ligament properties were implanted with a posterior-stabilized (PS) TKA. A 10° flexion contracture was created in each model to simulate a capsular contracture. Distal femoral resections of + 2 mm and + 4 mm were then simulated for each knee. The knee models were then extended under a standard moment. Subsequently, varus and valgus moments of 10 Nm were applied as the knee was flexed from 0° to 90° at baseline and repeated after each of the two distal resections. Coronal laxity (the sum of varus and valgus angulation with respective maximum moments) was measured throughout flexion. Results. With + 2 mm resection at 30° and 45° of flexion, mean coronal laxity increased by a mean of 3.1° (SD 0.18°) (p < 0.001) and 2.7° (SD 0.30°) (p < 0.001), respectively. With + 4 mm resection at 30° and 45° of flexion, mean coronal laxity increased by 6.5° (SD 0.56°) (p < 0.001) and 5.5° (SD 0.72°) (p < 0.001), respectively. Maximum increased coronal laxity for a + 4 mm resection occurred at a mean 15.7° (11° to 33°) of flexion with a mean increase of 7.8° (SD 0.2°) from baseline. Conclusion. With joint line elevation in primary PS TKA, coronal laxity peaks early (about 16°) with a maximum laxity of 8°. Surgeons should restore the joint line if possible; however, if joint line elevation is necessary, we recommend assessment of coronal laxity at 15° to 30° of knee flexion to assess for mid-flexion instability. Further in vivo studies are warranted to understand if this mid-flexion coronal laxity has negative clinical implications. Cite this article: Bone Joint J 2021;103-B(6 Supple A):87–93

Ligament reconstruction following multi-ligamentous knee injuries involves graft fixation in bone tunnels using interference screws (IS) or cortical suspensory systems. Risks of IS fixation include graft laceration, cortical fractures, prominent hardware, and inability to adjust tensioning once secured. Closed loop suspensory (CLS) fixation offers an alternative with fewer graft failures and improved graft-to-tunnel incorporation. However, graft tensioning cannot be modified to accommodate errors in tunnel length evaluation. Adjustable loop suspensory (ALS) devices (i.e., Smith & Nephew Ultrabutton) address these concerns and also offer the ability to sequentially tighten each graft, as needed. However, ALS devices may lead to increased graft displacement compared to CLS devices. Therefore, this study aims to report outcomes in a large clinical cohort of patients using both IS and CLS fixation. A retrospective review of radiographic, clinical, and patient-reported outcomes following ligament reconstruction from a Level 1 trauma centre was completed. Eligible patients were identified via electronic medical records using ICD-10 codes. Inclusion criteria were patients 18 years or older undergoing ACL, PCL, MCL, and/or LCL reconstruction between January 2018 and 2020 using IS and/or CLS fixation, with a minimum of six-month post-operative follow-up. Exclusion criteria were follow-up less than six months, incomplete radiographic imaging, and age less than 18 years. Knee dislocations (KD) were classified using the Schenck Classification. The primary outcome measure was implant removal rate. Secondary outcomes were revision surgery rate, deep infection rate, radiographic fixation failure rate, radiographic malposition, Lysholm and Tegner scores, clinical graft failure, and radiographic graft failure. Radiographic malposition was defined as implants over 5 mm off bone or intraosseous deployment of the suspensory fixation device. Clinical graft failure was defined as a grade II or greater Lachman, posterior drawer, varus opening at 20° of knee flexion, and/or valgus opening at 20° of knee flexion. Radiographic failure was defined when over 5 mm, 3.2 mm, and/or 2.7 mm of side-to-side difference occurred using PCL gravity stress views, valgus stress views, and/or varus stress views, respectively. Descriptive statistics were used. Sixty-three consecutive patients (mean age = 41 years, range = 19-58) were included. A total of 266 CLS fixation with Ultrabuttons and 135 IS were used. Mean follow-up duration was 383 days. Most injuries were KD type II and III. Graft revision surgery rate was 1.5%. Intraosseous deployment occurred in 6.2% and 17% had implants secured in soft tissue, rather than on bone. However, the implant removal rate was only 6.2%. Radiographic PCL gravity stress views demonstrated an average of 1.2 mm of side-to-side difference with 6.2% meeting criteria for radiographic failure. A single patient met radiographic failure criteria for collateral grafts. Mean Lysholm and Tegner scores were 87.3 and 4.4, respectively, with follow-up beyond one year. Both IS and CLS fixation demonstrate an extremely low revision surgery rate, a high rate of implant retention, excellent radiographic stability, and satisfactory patient-reported outcome scores. Incorrect implant deployment was seen in a total of 17% of patients, yet none required implant removal. A single patient required graft revision due to implant failure

Introduction and Objective. Malunion after trauma can lead to coronal plane malalignment in the lower limb. The mechanical hypothesis suggests that this alters the load distribution in the knee joint and that that this increased load may predispose to compartmental arthritis. This is generally accepted in the orthopaedic community and serves as the basis guiding deformity correction after malunion as well as congenital or insidious onset malalignment. Much of the literature surrounding the contribution of lower limb alignment to arthritis comes from cohort studies of incident osteoarthritis. There has been a causation dilemma perpetuated in a number of studies - suggesting malalignment does not contribute to, but is instead a consequence of, compartmental arthritis. In this investigation the relationship between compartmental (medial or lateral) arthritis and coronal plane malalignment (varus or valgus) in patients with post traumatic unilateral limb deformity was examined. This represents a specific niche cohort of patients in which worsened compartmental knee arthritis after extra-articular injury must rationally be attributed to malalignment. Materials and Methods. The picture archiving system was searched to identify all 1160 long leg x ray films available at a major metropolitan trauma center over a 12-year period. Images were screened for inclusion and exclusion criteria, namely patients >10 years after traumatic long bone fracture without contralateral injury or arthroplasty to give 39 cases. Alignment was measured according to established surgical standards on long leg films by 3 independent reviewers, and arthritis scores Osteoarthritis Research Society International (OARSI) and Kellegren-Lawrence (KL) were recorded independently for each compartment of both knees. Malalignment was defined conservatively as mechanical axis deviation outside of 0–20 mm medial from centre of the knee, to give 27 patients. Comparison of mean compartmental arthritis score was performed for patients with varus and valgus malalignment, using Analysis of Variance and linear regression. Results. In knees with varus malalignment there was a greater mean arthritis score in the medial compartment compared to the contralateral knee, with OARSI scores 5.69 vs 3.86 (0.32, 3.35 95% CI; p<0.05) and KL 2.92 vs 1.92 (0.38, 1.62; p<0.005). There was a similar trend in valgus knees for the lateral compartment OARSI 2.98 vs 1.84 (CI −0.16, 2.42; p=0.1) and KL 1.76 vs 1.31 (CI −0.12, 1.01; p=0.17), but the evidence was not conclusive. OARSI arthritis score was significantly associated with absolute MAD (0.7/10mm MAD, p<0.0005) and Time (0.6/decade, p=0.01) in a linear regression model. Conclusions. Malalignment in the coronal plane is correlated with worsened arthritis scores in the medial compartment for varus deformity and may similarly result in worsened lateral compartment arthritis in valgus knees. These findings support the mechanical hypothesis that arthritis may be related to altered stress distribution at the knee, larger studies may provide further conclusive evidence

Aims. The impact of a diaphyseal femoral deformity on knee alignment varies according to its severity and localization. The aims of this study were to determine a method of assessing the impact of diaphyseal femoral deformities on knee alignment for the varus knee, and to evaluate the reliability and the reproducibility of this method in a large cohort of osteoarthritic patients. Methods. All patients who underwent a knee arthroplasty from 2019 to 2021 were included. Exclusion criteria were genu valgus, flexion contracture (> 5°), previous femoral osteotomy or fracture, total hip arthroplasty, and femoral rotational disorder. A total of 205 patients met the inclusion criteria. The mean age was 62.2 years (SD 8.4). The mean BMI was 33.1 kg/m. 2. (SD 5.5). The radiological measurements were performed twice by two independent reviewers, and included hip knee ankle (HKA) angle, mechanical medial distal femoral angle (mMDFA), anatomical medial distal femoral angle (aMDFA), femoral neck shaft angle (NSA), femoral bowing angle (FBow), the distance between the knee centre and the top of the FBow (DK), and the angle representing the FBow impact on the knee (C’KS angle). Results. The FBow impact on the mMDFA can be measured by the C’KS angle. The C’KS angle took the localization (length DK) and the importance (FBow angle) of the FBow into consideration. The mean FBow angle was 4.4° (SD 2.4; 0 to 12.5). The mean C’KS angle was 1.8° (SD 1.1; 0 to 5.8). Overall, 84 knees (41%) had a severe FBow (> 5°). The radiological measurements showed very good to excellent intraobserver and interobserver agreements. The C’KS increased significantly when the length DK decreased and the FBow angle increased (p < 0.001). Conclusion. The impact of the diaphyseal femoral deformity on the mechanical femoral axis is measured by the C’KS angle, a reliable and reproducible measurement. Cite this article: Bone Jt Open 2023;4(4):262–272

Introduction and Objective. Distal femoral fractures are commonly treated with a straight plate fixed to the lateral aspects of both proximal and distal fragments. However, the lateral approach may not always be desirable due to persisting soft-tissue or additional vascular injury necessitating a medial approach. These problems may be overcome by pre-contouring the plate in helically shaped fashion, allowing its distal part to be fixed to the medial aspect of the femoral condyle. The objective of this study was to investigate the biomechanical competence of medial femoral helical plating versus conventional straight lateral plating in an artificial distal femoral fracture model. Materials and Methods. Twelve left artificial femora were instrumented with a 15-hole Locking Compression Plate – Distal Femur (LCP-DF) plate, using either conventional lateral plating technique with the plate left non-contoured, or the medial helical plating technique by pre-contouring the plate to a 180° helical shape and fixing its distal end to the medial femoral condyle (n=6). An unstable extraarticular distal femoral fracture was subsequently simulated by means of an osteotomy gap. All specimens were tested under quasi-static and progressively increasing cyclic axial und torsional loading until failure. Interfragmentary movements were monitored by means of optical motion tracking. Results. Initial axial stiffness was significantly higher for helical (185.6±50.1 N/mm) versus straight (56.0±14.4) plating, p<0.01. However, initial torsional stiffness in internal and external rotation remained not significantly different between the two fixation techniques (helical plating:1.59±0.17 Nm/° and 1.52±0.13 Nm/°; straight plating: 1.50±0.12 Nm/° and 1.43±0.13Nm/°), p≥0.21. Helical plating was associated with significantly higher initial interfragmentary movements under 500 N static compression compared to straight plating in terms of flexion (2.76±1.02° versus 0.87±0.77°) and shear displacement under 6 Nm static rotation in internal (1.23±0.28° versus 0.40±0.42°) and external (1.21±0.40° versus 0.57±0.33°) rotation, p≤0.01. In addition, helical plating demonstrated significantly lower initial varus/valgus deformation than straight plating (4.08±1.49° versus 6.60±0.47°), p<0.01. Within the first 10000 cycles of dynamic loading, helical plating revealed significantly bigger flexural movements and significantly lower varus/valgus deformation versus straight plating, p=0.02. No significant differences were observed between the two fixation techniques in terms of axial and shear displacement, p≥0.76. Cycles to failure was significantly higher for helical plating (13752±1518) compared to straight plating (9727±836), p<0.01. Conclusions. Although helical plating using a pre-contoured LCP-DF was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, helical plate constructs demonstrated significantly improved endurance to failure, which may be attributed to the less progressively increasing lever bending moment arm inherent to this novel fixation technique. From a biomechanical perspective, helical plating may be considered as a valid alternative fixation technique to standard straight lateral plating of unstable distal femoral fractures

Abstract. Background. Conventional TKR aims for neutral mechanical alignment which may result in a smaller lateral distal femoral condyle resection than the implant thickness. We aim to explore the mismatch between implant thickness and bone resection using 3D planning software used for Patient Specific Instrumentation (PSI) TKR. Methods. This is a retrospective anatomical study from pre-operative MRI 3D models for PSI TKR. Cartilage mapping allowed us to recreate the native anatomy, enabling us to quantify the mismatch between the distal lateral femoral condyle resection and the implant thickness. Results. We modelled 292 knees from PSI TKR performed between 2012 and 2015. There were 225 varus knees and 67 valgus knees, with mean supine hip-knee-angle of 5.6±3.1 degrees and 3.6±4.6 degrees, respectively. In varus knees, the mean cartilage loss from medial and lateral femoral condyle was 2.3±0.7mm and 1.1±0.8mm respectively; the mean overstuffing of the lateral condyle 1.9±2.2mm. In valgus knees, the mean cartilage loss from medial and lateral condyle was 1.4±0.8mm and 1.5±0.9mm respectively; the mean overstuffing of the lateral condyle was 4.1±1.9mm. Conclusions. Neutral alignment TKR often results in overstuffing of the lateral condyle. This may increase the patello-femoral pressure at the lateral facet in flexion. Anterior knee pain may be persistent even after patellar resurfacing due to tight lateral retinacular structures. An alternative method of alignment such as anatomic alignment may minimise this problem

Aims. The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery. Methods. An analysis of 38 patients who underwent TKA and 32 who underwent bi-UKA was performed as a secondary study from a prospective, single-centre, randomized controlled trial. CT imaging was used to measure coronal, sagittal, and axial alignment of the knee preoperatively and at three months postoperatively to determine changes in anatomy that had occurred as a result of the surgery. The hip-knee-ankle angle (HKAA) was also measured to identify any differences between the two groups. Results. The pre- to postoperative changes in joint anatomy were significantly less in patients undergoing bi-UKA in all three planes in both the femur and tibia, except for femoral sagittal component orientation in which there was no difference. Overall, for the six parameters of alignment (three femoral and three tibial), 47% of bi-UKAs and 24% TKAs had a change of < 2° (p = 0.045). The change in HKAA towards neutral in varus and valgus knees was significantly less in patients undergoing bi-UKA compared with those undergoing TKA (p < 0.001). Alignment was neutral in those undergoing TKA (mean 179.5° (SD 3.2°)) while those undergoing bi-UKA had mild residual varus or valgus alignment (mean 177.8° (SD 3.4°)) (p < 0.001). Conclusion. Robotic-assisted, cruciate-sparing bi-UKA maintains the natural anatomy of the knee in the coronal, sagittal, and axial planes better, and may therefore preserve normal joint kinematics, compared with a mechanically aligned TKA. This includes preservation of coronal joint line obliquity. HKAA alignment was corrected towards neutral significantly less in patients undergoing bi-UKA, which may represent restoration of the pre-disease constitutional alignment (p < 0.001). Cite this article: Bone Joint J 2020;102-B(11):1511–1518

Abstract. Objectives. Stem malalignment in total hip arthroplasty (THA) has been associated with poor long-term outcomes and increased complications (e.g. periprosthetic femoral fractures). Our understanding of the biomechanical impact of stem alignment in cemented and uncemented THA is still limited. This study aimed to investigate the effect of stem fixation method, stem positioning, and compromised bone stock in THA. Methods. Validated FE models of cemented (C-stem – stainless steel) and uncemented (Corail – titanium) THA were developed to match corresponding experimental model datasets; concordance correlation agreement of 0.78 & 0.88 for cemented & uncemented respectively. Comparison of the aforementioned stems was carried out reflecting decisions made in the current clinical practice. FE models of the implant positioned in varus, valgus, and neutral alignment were then developed and altered to represent five different bone defects according to the Paprosky classification (Type I – Type IIIb). Strain was measured on the femur at 0mm (B1), 40mm (B2), and 80mm (B3) from the lesser trochanter. Results. Cemented constructs had lower strain on the implant neck, and higher overall stiffness and strain on bone compared to uncemented THA. Strain on the bone increased further down the shaft of the femoral diaphysis, and with progressing bone defect severity in all stem alignment cases. Highest strain on the femur was found at B2 in all stem alignment and bone defect models. Varus alignment showed higher overall femoral strain in both fixation methods. Interestingly, in uncemented models, highest strain was shown on femoral bone proximally (B1-B2) in varus alignment, but distally (B3) in neutral alignment. Conclusion. Varus stem alignment showed overall higher strain on femur compared to neutral and valgus. This highlights the crucial role of stem alignment in long term outcomes of THA. Differences between the two stem types should be taken in consideration when interpreting results from this study

Mechanical alignment (MA) techniques for total knee arthroplasty (TKA) may introduce significant anatomic modifications, as it is known that few patients have neutral femoral, tibial or overall lower limb mechanical axes. A total of 1000 knee CT-Scans were analyzed from a database of patients undergoing TKA. MA tibial and femoral bone resections were simulated. Femoral rotation was aligned with either the trans-epicondylar axis (TEA) or with 3° of external rotation to the posterior condyles (PC). Medial-lateral (DML) and flexion-extension (DFE) gap differences were calculated. Extension space ML imbalances (3mm) occurred in 25% of varus and 54% of valgus knees and significant imbalances (5mm) were present in up to 8% of varus and 19% of valgus knees. For the flexion space DML, higher imbalance rates were created by the TEA technique (p < 0 .001). In valgus knees, TEA resulted in a DML in flexion of 5 mm in 42%, compared to 7% for PC. In varus knees both techniques performed better. When all the differences between DML and DFE are considered together, using TEA there were 18% of valgus knees and 49% of varus knees with < 3 mm imbalances throughout, and using PC 32% of valgus knees and 64% of varus knees. Significant anatomic modifications with related ML or FE gap imbalances are created using MA for TKA. Using MA techniques, PC creates less imbalances than TEA. Some of these imbalances may not be correctable by the surgeon and may explain post-operative TKA instability. Current imaging technology could predict preoperatively these intrinsic imitations of MA. Other alignment techniques that better reproduce knee anatomies should be explored

Introduction. Valgus deformity in an end stage osteoarthritic knee can be difficult to correct with no clear consensus on case management. Dependent on if the joint can be reduced and the degree of medial laxity or distension, a surgeon must use their discretion on the correct method for adequate lateral releases. Robotic assisted (RA) technology has been shown to have three dimensional (3D) cut accuracy which could assist with addressing these complex cases. The purpose of this work was to determine the number of soft tissue releases and component orientation of valgus cases performed with RA total knee arthroplasty (TKA). Methods. This study was a retrospective chart review of 72 RATKA cases with valgus deformity pre-operatively performed by a single surgeon from July 2016 to December 2017. Initial and final 3D component alignment, knee balancing gaps, component size, and full or partial releases were collected intraoperatively. Post-operatively, radiographs, adverse events, WOMAC total and KOOS Jr scores were collected at 6 months, 1 year and 2 year post-operatively. Results. Pre-operatively, knee deformities ranged from reducible knees with less than 5mm of medial laxity to up to 12° with fixed flexion contracture. All knees were corrected within 2.5 degrees of mechanical neutral. Average femoral component position was 0.26. o. valgus, and 4.07. o. flexion. Average tibial component position was 0.37. o. valgus, and 2.96. o. slope, where all tibial components were placed in a neutral or valgus orientation. Flexion and extension gaps were within 2mm (mean 1mm) for all knees. Medial and lateral gaps were balanced 100% in extension and 93% in flexion. The average flexion gap was 18.3mm and the average extension gap was 18.7mm. For component size prediction, the surgeon achieved their planned within one size on the femur 93.8% and tibia 100% of the time. The surgeon upsized the femur in 6.2% of cases. Soft tissue releases were reported in one of the cases. At latest follow-up, radiographic evidence suggested well seated and well fixed components. Radiographs also indicated the patella components were tracking well within the trochlear groove. No revision and re-operation is reported. Mean WOMAC total scores were improved from 24±8.3 pre-op to 6.6±4.4 2-year post-op (p<0.01). Mean KOOS scores were improved from 46.8±9.7 pre-op to 88.4±13.5 2-year post-op (p<0.01). Discussion. In this retrospective case review, the surgeon was able to balance the knee with bone resections and avoid disturbing the soft tissue envelope in valgus knees with 1–12° of deformity. To achieve this balance, the femoral component was often adjusted in axial and valgus rotations. This allowed the surgeon to open lateral flexion and extension gaps. While this study has several limitations, RATKA for valgus knees should continue to be investigated. For any figures or tables, please contact authors directly

Known risk factors for early periprosthetic femur fracture (PFF) following total hip arthroplasty (THA) include poor bone quality, surgical approach and cementless implants. The association between femoral component size and alignment and the risk of early PFF is not well described. We evaluated radiographic parameters of femoral component sizing and alignment as risk factors for early PFF. From 16,065 primary cementless THA, we identified 66 cases (0.41%) of early PFF (<90 days from index THA) at a single institution between 2016–2020. The stem was unstable and revised in all cases. We matched 60 cases of early PFFs (2:1) to 120 controls based on femoral component model, offset, surgical approach, age, BMI, and sex. Mean age was 67 years; 60% were female. Radiographic assessment of preoperative bone morphology and postoperative femoral component parameters including stem alignment, metaphyseal fill, and medial congruence with the calcar. A multivariable logistic regression was built to identify radiographic risk factors associated with early PPF. Markers of poor preoperative bone quality including canal calcar ratio (p=0.003), canal flare index (p<0.001), anteroposterior canal bone ratio (CBR) (p<0.001) and lateral CBR (p<0.001) were statistically associated with PFF. Valgus alignment (23% versus 12%) (p<0.001) was more prevalent in the PFF group compared to controls, as well as varus alignment of the implant (57% versus 43%). Distance between the medial aspect of the implant and the calcar was greater in cases of PFF (2.5 mm versus 1.4 mm) (p<0.001). Multivariate analysis demonstrated that valgus implant alignment (Odds Ratio (OR) 5) and medial implant-calcar incongruity (OR 2) increased the risk of early PFF. Medial implant-calcar incongruity and valgus alignment of the femoral component were risk factors for early PFF following cementless THA after controlling for age, sex, BMI, approach, proximal femoral morphology, and implant design

Intertrochanteric fractures are common, accounting for nearly 30% of all fracture related admissions. Some have suggested that these fractures should be treated in community hospitals so as not to tax the resources of Level One trauma centers. Since many factors predictive of fixation failure are related to technical aspects of the surgery, the purpose of this study was to compare radiographic parameters after fixation comparing trauma fellowship trained surgeons to non-fellowship trained community surgeons to see if these fractures can be treated successfully in either setting. Using our hospital system's trauma database, we identified 100 consecutive patients treated with cephalomedullary nails by traumatologists, and 100 consecutive patients treated by community surgeons. Quality of reduction, neck shaft angle (NSA), tip-to apex distance (TAD) were compared. The mean TAD for the trauma group was 10mm compared to 21mm for the community group (p<0.001). The mean postoperative NSA for the trauma group was 133 degrees compared to 127 degrees for the community group (p<0.001). The mean difference in the NSA of the fractured side compared to the normal hip was 2.5 degrees of valgus in the trauma group compared to 5 degrees of varus for the community group (p<0.001). There were 93 good reductions in the trauma group compared to 19 in the community group (p<0.001). There were no poor reductions in the trauma group and 49 poor reductions in the community group (p<0.001). Fellowship trained traumatologists achieved significantly more accurate reductions and implant placement during cephalomedullary nailing of intertrochanteric hip fractures

Introduction. Instability is a common reason for revision after total knee arthroplasty. A balanced flexion gap is likely to enhance stability throughout the arc of motion. This is achieved differently by the gap balancing and measured resection techniques. Given similar clinical results with the two techniques, one would expect similar rotation of the femoral component in the axial plane. We assessed posterior-stabilized femoral component axial rotation placed with computer navigation and a modified gap balancing technique. We hypothesized that there would be little variation in rotation. Methods. 90 surgeons from 8 countries used a modified gap-balancing technique and the same posterior-stabilized implant for this retrospective study. Axial rotation of the femoral component was collected from a navigation system and reported relative to the posterior condylar line. Patients were stratified by their preoperative coronal mechanical alignment (≥ 3° varus, < 3° varus to < 3° valgus, and ≥ 3° valgus). Results. 2442 consecutive patients were included in the analysis; 835 with ≥ 3° varus, 1343 with < 3° varus to < 3° valgus, and 264 with ≥ 3° valgus. Mean rotation was external 2.4. 0. +/− 3.4. 0. (range, 10. 0. internal − 21. 0. external). In 16.4% of the cohort, axial rotation was set in a position of internal rotation. In 15.6% of the cohort, axial rotation was set at > 5. 0. of external rotation. Compared to both the neutral and varus groups, valgus knees required a different mean rotation to achieve a balanced flexion gap (p < .0001). Conclusion. These data show a wide range of femoral rotation was needed to achieve a rectangular flexion gap. This suggests that choosing a pre-determined femoral implant axial rotation (measured resection) may lead to flexion gap asymmetry more frequently compared to adjusting the axial rotation intraoperatively (gap-balancing). Correlation to clinical outcome scores is needed

Abstract. Introduction. Anecdotal reports suggest some cementless Oxford Unicompartmental Knee Replacements (OUKRs) have painful early subsidence of the tibial component with valgus rotation and/or posterior tilting. The incidence of subsidence and its association with pain is poorly understood. This radiographic study aimed to evaluate the incidence of tibial subsidence and five-year patient reported outcome measures (PROMs) of a cementless OUKR cohort. Methodology. Cementless OUKRs from a high-volume centre with acceptable post-operative and five-year radiographs were included. Subsidence was determined by measuring the angle of the tibial tray/tibial axis angle and distance between the tibial tray axis and fibula head on anteroposterior and lateral radiographs using a custom MATLAB program. Analysis of 5-year PROMs assessed the relationship between subsidence and pain. Radiographs indicating tibial subsidence were validated by two observers. Results. Radiographs of 94 cementless OUKRs were analysed of which five tibial components had subsided (incidence=5%) with an average of 1.92° varus rotation and 2.97° posterior tilt. Subsidence appeared to occur within the first post-operative year with all tibial components fixed securely at 5 years. Two subsiders had moderate pain (ICOAP=20.5,15.9, AKSS Pain=20,45) and lower Oxford Knee Scores (OKS=26,31) compared to the cohort means (ICOAP=3.91, AKSS Pain=45.9, OKS = 43.6). These two subsiders had BMIs greater than 30. Conclusion. This study found 5% of cementless OUKRs in the cohort underwent tibial subsidence. Subsidence with moderate pain occurred in 2% of cases, and pain may be associated with obesity. A larger study is needed to study subsidence in greater detail

Abstract. Aims. Growth disturbances after transphyseal paediatric ACL reconstruction have led to the development of physeal-sparing techniques. However, evidence in their favour remains weak. This study reviews the literature to identify factors associated with growth disturbances in paediatric ACL reconstructions. Materials and Methods. Web of Science, Scopus and Pubmed were searched for case series studying paediatric ACL reconstructions. Titles, abstracts, text, results and references were examined for documentation of growth disturbances. Incidences of graft failures were also studied in these selected studies. Results. 78 studies with 2693 paediatric ACL reconstructions had 70 growth disturbances (2.6%). Of these 17 were varus, 26 valgus, 13 shortening, 14 lengthening and 5 patients had reduced tibial slope. Coronal plane deformities were seen more frequently with eccentric physeal arrest and lengthening with intraepiphyseal tunnelling. Shortening and reduced tibial slope were related to large central physeal arrest and anterior tibial physeal arrest respectively. Extraphyseal technique were least likely to have growth disturbances. 62 studies documented 166 graft failures in 2120 patients (7.83%). Conclusion. Growth disturbances resulting from transphyseal ACL reconstruction can be minimised by keeping drill size small, drilling steep and away from the physeal periphery. Insertion of bone plug, hardware or synthetic material through the drilled physis should be avoided. The evidence to accurately quantify such growth disturbances till skeletal maturity remains weak. Robust long term studies such as national ligament registries may standardise preoperative and postoperative outcome assessment to further characterise the risk of growth disturbance and re-ruptures

Abstract. INTRODUCTION. The anatomic distal femoral locking plate (DF-LCP) has simplified the management of supracondylar femoral fractures with stable knee prostheses. Osteoporosis and comminution seem manageable, but at times, the construct does not permit early mobilization. Considerable soft tissue stripping during open reduction and internal fixation (ORIF) may delay union. Biological plating offsets this disadvantage, minimizing morbidity. Materials. Thirty comminuted periprosthetic supracondylar fractures were operated from October 2010 to August 2016. Fifteen (group A) were treated with ORIF, and fifteen (group B) with closed (biological) plating using the anatomical DF-LCP. Post-operatively, standard rehabilitation protocol was followed in all, with hinged-knee-brace supported physiotherapy. Clinico-radiological follow-up was done at 3 months, 6 months, and then yearly (average duration, 30 months), and time to union, complications, failure rates and function were evaluated. Results. Average time to union was 4.5 months (range, 3–6 months) in group A, and 3.5 months (range, 2.5–5 months) in group B. Primary bone grafting was done in twelve patients (all group A). At final follow-up, all fractures had healed, and all (but two) patients were walking unsupported, with no pain or deformity, with average knee range of motion (ROM) of 90° (range, 55 to 100°). Two patients had superficial infection (group A), two had knee stiffness (group A), one had shortening of 1.5cm (group B) and one had valgus malalignment of 10 degrees (group B). Conclusion. Biological plating in comminuted supracondylar fractures about stable TKA prostheses is an excellent option, may obviate need for bone grafting, and reducing complications

Background. The effect of hallux valgus (HV) on health-related quality of life (HRQOL) and the relationship between radiographic severity of deformity and patient reported outcome measures (PROMs) is poorly understood. The aim of this study was to compare the HRQOL of female patients with HV to the UK population. The secondary aim was to assess the correlation between PROMs, including HRQOL, with radiographic severity of deformity. Methods. Weight bearing radiographic data (hallux valgus (HVA) angle; intermetatarsal (IM) angle) were measured in consecutive female patients presenting with HV. Each patient prospectively completed the Euroqol EQ-5D-5L questionnaire (EQ-5D), Visual Analogue Scale for Pain (VAS-Pain) and Manchester Oxford Foot Questionnaire (MOXFQ). Data were stratified into age ranges and compared with an EQ-5D United Kingdom general population reference dataset. Pearson R correlation values were calculated for the PROMs and radiographic deformity. Results. Between July 2015 and March 2020, 425 consecutive female patients presented with HV for consideration for surgery. EQ-5D-5L data were prospectively collected for 396 of these patients (93.2%). Females less than 65 years with HV had a statistically significantly worse quality of life compared with females of the same age group in the general population. Above the age of 65, there was no statistically significant difference in EQ-5D-5L Index score between the two groups. There was no correlation between radiographic HV deformity and HRQOL measures or MOXFQ scores. Conclusion. Female patients presenting with HV deformity have a significantly reduced quality of life compared with the UK general population. The radiographic severity of deformity did not correlate with HRQOL measures or foot and ankle specific PROMs. Foot and ankle specific clinical PROMs moderately correlate with HRQOL and may be a better marker of the negative effect of symptomatic hallux valgus deformity on quality of life

Abstract. Background. Multi-ligament knee injury is a rare but severe injury. Treatment strategies are challenging for most orthopedic surgeons & optimal treatment remains controversial. The purpose of our study was to assess clinico-radiological and functional outcomes after surgical management of multi-ligament knee injuries & to determine factors that could predict outcome of surgery. Materials And Method. It is a prospective observational study of 30 consecutive patients of Multi-ligament knee injury conducted between 2018–2020. All patients were treated surgically with single-stage reconstruction of all injured ligaments and followed standardized postoperative rehabilitation protocol. All patients were evaluated for Clinical (VAS score, laxity stress test, muscle-strength, range of motion), Radiological (stress radiographs) & Functional (Lysholm score) outcomes three times-preoperatively, post-operative 3 & 12 months. Results. At final follow up mean VAS score was 0.86±0.77. The anteroposterior & valgus-varus stress test showed ligament laxity >10mm (GradeD) in 93.3% patient which improved to <3mm (normal, GradeA) in 90% patients. Most patients (83.3%) had preoperative-range <100° and muscle strength of MRC Grade-3 which improved to >120° and muscle strength of MRC grade-5 at final followup. Lysholm score was poor (<64) in all patients preoperatively and improved to good (85–94) in 73.3%, excellent (>95) in 20% & fair (65–84) in 6.6% patients. The stress radiographs showed stable results for anterior/posterior & varus/valgus stress. All patients returned to their previous work. Factors that could predict outcomes of surgery are age, timing of surgery, type of surgery & associated injury. Conclusion. Early complete single stage reconstruction can achieve good functional results with overall restoration of sports & working capacity. Positive predictive factors for good outcome are younger age, early surgery & appropriate rehabilitation

Partial meniscectomy patients have a greater likelihood for the development of early osteoarthritis (OA). To prevent the onset of early OA, patient-specific treatment algorithms need to be created that predict patient risk to early OA after meniscectomy. The aim of this work was to identify patient-specific risk factors in partial meniscectomy patients that could potentially lead to early OA. Partial meniscectomy patients operated between 01/2017 and 12/2019 were evaluated in the study (n=317). Exclusion criteria were other pathologies or surgeries for the evaluated knee and meniscus (n = 114). Following informed consent, an online questionnaire containing demographics and the “Knee Injury and Osteoarthritis Outcome Score” (KOOS) questionnaire was sent to the patient. Based on the KOOS pain score, patients were classified into “low” (> 75) and “high” (< 75) risk patients, indicating risk to symptomatic OA. The “high risk” patients also underwent a follow-up including an MRI scan to understand whether they have developed early OA. From 203 participants, 96 patients responded to the questionnaire (116 did not respond) with 61 patients considered “low-risk” and 35 “high-risk” patients. Groups that showed a significant increased risk for OA were patients aged > 40 years, females, overweight (BMI >25 kg/m2 ≤ 30 kg/m2), and smokers (*p < 0.05). The “high-risk”-follow-up revealed a progression of early osteoarthritic cartilage changes in seven patients, with the remaining nineteen patients showing no changes in cartilage status or pain since time of operation. Additionally, eighteen patients in the high-risk group showed a varus or valgus axis deviation. Patient-specific factors for worse postoperative outcomes after partial meniscectomy and indicators for an “early OA” development were identified, providing the basis for a patient-specific treatment approach. Further analysis in a multicentre study and computational analysis of MRI scans is ongoing to develop a patient-specific treatment algorithm for meniscectomy patients

Background. The importance of total ankle replacement (TAR) implant orientation in the axial plane is poorly understood with major variation in surgical technique of implants on the market. Our aims were to better understand the axial rotational profile of patients undergoing TAR. Methods. In 157 standardised CT Scans of end-stage ankle arthritis patients planning to undergo primary TAR surgery, we measured the relationship between the knee posterior condylar axis, the tibial tuberosity, the transmalleolar axis(TMA) and the tibiotalar angle. The foot position was measured in relation to the TMA with the foot plantigrade. The variation between medial gutter line and the line bisecting both gutters was assessed. Results. The mean external tibial torsion was 34.5±10.3°(11.8–62°). When plantigrade the mean foot position relative to the TMA was 21±10.6°(0.7–38.4°) internally rotated. As external tibial torsion increased, the foot position became more internally rotated relative to the TMA(pearson correlation 0.6;p< 0.0001). As the tibiotalar angle became more valgus, the foot became more externally rotated relative to the TMA(pearson correlation −0.4;p< 0.01). The mean difference between the medial gutter line and a line bisecting both gutters was 4.9±2.8°(1.7°-9.4°). More than 51% of patients had a difference greater than 5°. The mean angle between the medial gutter line and a line perpendicular to the TMA was 7.5°±2.6°(2.8°-13.7°). Conclusion. There is a large variation in rotational profile of patients undergoing TAR, particularly between the medial gutter line and the transmalleolar axis. Surgeon designers and implant manufacturers need to develop consistent methods to guide surgeons towards judging appropriate axial rotation of their implanton an individual basis. We recommend careful clinical assessment and CT scanspre-operatively to enable the correct rotation to be determined

The use of shorter humeral stems in reverse shoulder arthroplasty has been reported as safe and effective. Shorter stems are purported to be bone preserving, easy to revise, and have reduced surgical time. However, a frequent radiographic finding with the use of uncemented short stems is stress shielding. Smaller stem diameters reduce stress shielding, however, carry the risk of varus or valgus malalignment in the metadiaphyseal region of the proximal humerus. The aim of this retrospective radiographic study was to measure the true post-operative neck-shaft (N-S) angle of a curved short stem with a recommended implantation angle of 145°. True anteroposterior radiographs of patients who received RTSA using an Ascend Flex short stem at three specialized shoulder centres (London, ON, Canada, Lyon, France, Munich, Germany) were reviewed. Radiographs that showed the uncemented stem and humeral tray in orthogonal view without rotation were included. Sixteen patients with proximal humeral fractures or revision surgeries were excluded. This yielded a cohort of 124 implant cases for analysis (122 patients, 42 male, 80 female) at a mean age of 74 years (range, 48 – 91 years). The indications for RTSA were rotator cuff deficient shoulders (cuff tear arthropathy, massive cuff tears, osteoarthritis with cuff insufficiency) in 78 patients (63%), primary osteoarthritis in 41 (33%), and rheumatoid arthritis in 5 (4%). The humeral component longitudinal axis was measured in degrees and defined as neutral if the value fell within ±5° of the humeral axis. Angle values >5° and < 5 ° were defined as valgus and varus, respectively. The filling-ratio of the implant within the humeral shaft was measured at the level of the metaphysis (FRmet) and diaphysis (FRdia). Measurements were conducted by two independent examiners (SA and TW). To test for conformity of observers, the intraclass correlation coefficient (ICC) was calculated. The inter- and intra-observer reliability was excellent (ICC = 0.965, 95% confidence interval [CI], 0.911– 0.986). The average difference between the humeral shaft axis and the humeral component longitudinal axis was 3.8° ± 2.8° (range, 0.2° – 13.2°) corresponding to a true mean N-S angle of 149° ± 3° in valgus. Stem axis was neutral in 70% (n=90) of implants. Of the 34 malaligned implants, 82% (n=28) were in valgus (mean N-S angle 153° ± 2°) and 18% (n=6) in varus position (mean N-S angle 139° ± 1°). The average FRmet and FRdiawere 0.68 ± 0.11 and 0.72 ± 0.11, respectively. No association was found between stem diameter and filling ratios (FRmet, FRdia) or cortical contact with the stem (r = 0.39). Operative technique and implant design affect the ultimate positioning of the implant in the proximal humerus. This study has shown, that in uncemented short stem implants, neutral axial alignment was achieved in 70% of cases, while the majority of malaligned humeral components (86%) were implanted in valgus, corresponding to a greater than 145° neck shaft angle of the implant. It is important for surgeons to understand that axial malalignment of a short stem implant does influence the true neck shaft angle

Objectives. Malalignment of the tibial component could influence the long-term survival of a total knee arthroplasty (TKA). The object of this study was to investigate the biomechanical effect of varus and valgus malalignment on the tibial component under stance-phase gait cycle loading conditions. Methods. Validated finite element models for varus and valgus malalignment by 3° and 5° were developed to evaluate the effect of malalignment on the tibial component in TKA. Maximum contact stress and contact area on a polyethylene insert, maximum contact stress on patellar button and the collateral ligament force were investigated. Results. There was greater total contact stress in the varus alignment than in the valgus, with more marked difference on the medial side. An increase in ligament force was clearly demonstrated, especially in the valgus alignment and force exerted on the medial collateral ligament also increased. Conclusion. These results highlight the importance of accurate surgical reconstruction of the coronal tibial alignment of the knee joint. Varus and valgus alignments will influence wear and ligament stability, respectively in TKA. Cite this article: D-S. Suh, K-T. Kang, J. Son, O-R. Kwon, C. Baek, Y-G. Koh. Computational study on the effect of malalignment of the tibial component on the biomechanics of total knee arthroplasty: A Finite Element Analysis. Bone Joint Res 2017;6:623–630. DOI: 10.1302/2046-3758.611.BJR-2016-0088.R2

Roentgen Stereophotogrammetric Analysis (RSA) is the gold standard for measuring implant micromotion thereby predicting implant loosening. Early migration has been associated with the risk of long-term clinical failure. We used RSA to assess the stability of the Australian designed cementless hip stem (Paragon TM) and now report our 5-year results. Fifty-three patients were prospectively and consecutively enrolled to receive a Paragon hip replacement. Tantalum beads were inserted into the bone as per RSA protocol and in the implant. RSA x-rays were taken at baseline 1–4 days post-surgery, at 6 weeks, 6 months, 12 months, 2 years, and 5 years. RSA was completed by an experienced, independent assessor. We reported the 2-year results on 46 hips (ANZJS 91 (3) March 2021 p398) and now present the 5-year results on 27 hips. From the 2-year cohort 5 patients had died, 8 patients were uncontactable, 1 patient was too unwell to attend, 5 patients had relocated too far away and declined. At 5 years the mean axial subsidence of the stem was 0.66mm (0.05 to 2.96); the mean rotation into retroversion was 0.49˚ (−0.78˚ to 2.09˚), rotation of the stem into valgus was −0.23˚ (−0.627˚ to 1.56˚). There was no detectable increase in subsidence or rotation between 6 weeks and 5 years. We compared our data to that published for the Corail cementless stem and a similar pattern of migration was noted, however greater rotational stability was achieved with the Paragon stem over a comparable follow-up period. The RSA results confirm that any minor motion of the Paragon cementless stem occurs in the first 6 weeks after which there is sustained stability for the next 5 years. The combination of a bi-planar wedge and transverse rectangular geometry provide excellent implant stability that is comparable to or better than other leading cementless stems

Applications of weightbearing computed tomography (WBCT) imaging in the foot and ankle have emerged over the past decade. However, the potential diagnostic benefits are scattered across the literature, and a concise overview is currently lacking. Therefore, we aimed to systematically review all reported diagnostic applications per anatomical region in the foot and ankle. A systematic literature search was performed in the electronic databases PubMed, EMBASE, Cochrane Library, and Web of Science. Search terms consisted of “weightbearing/standing CT and ankle, hind-, mid- or forefoot”. English language studies analyzing the diagnostic applications of WBCT were included. Studies were excluded if they simulated weightbearing CT, described normal subjects, included cadaveric samples or samples were case reports. The modified Methodological Index for Non-Randomized Studies (MINORS) was applied for quality assessment. The added value was defined as the review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and registered in the Prospero database (CRD42019106980). A total of 48 studies (prospective N=8, retrospective N=36, cohort study N=1, diagnostic N=2, prognostic comparative study N=1) were found to be eligible for review. The following diagnostic applications were identified per anatomical area in the foot: ankle (osteoarthritis N=5, ligament injury N=6); hindfoot (deformity N=9); midfoot (Lisfranc injury N=2, flatfoot deformity N=13, osteoarthritis N=1); forefoot (hallux valgus N=12). The identified studies contained diagnostic applications that could not be used on plain radiographs. The mean MINORS equaled 10.1 on a total of 16 (range: 8 to 12). Diagnostic applications of weightbearing CT imaging are most frequently studied in hindfoot deformity, but other area's areas are on the rise. Post-processing of images was identified as the main added value compared to WBRX. However, the findings should be interpreted with caution as the average quality score was moderate. Therefore, future prospective studies are warranted to consolidate the role of WBCT in diagnostic and therapeutic algorithms

The Coronal Plane Alignment of the Knee (CPAK) is a recent method for classifying knees using the hip-knee-ankle angle and joint line obliquity to assist surgeons in selection of an optimal alignment philosophy in total knee arthroplasty (TKA)1. It is unclear, however, how CPAK classification impacts pre-operative joint balance. Our objective was to characterise joint balance differences between CPAK categories. A retrospective review of TKA's using the OMNIBotics platform and BalanceBot (Corin, UK) using a tibia first workflow was performed. Lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were landmarked intra-operatively and corrected for wear. Joint gaps were measured under a load of 70–90N after the tibial resection. Resection thicknesses were validated to recreate the pre-tibial resection joint balance. Knees were subdivided into 9 categories as described by MacDessi et al.1 Differences in balance at 10°, 40° and 90° were determined using a one-way 2-tailed ANOVA test with a critical p-value of 0.05. 1124 knees satisfied inclusion criteria. The highest proportion of knees (60.7%) are CPAK I with a varus aHKA and Distal Apex JLO, 79.8% report a Distal Apex JLO and 69.3% report a varus aHKA. Greater medial gaps are observed in varus (I, IV, VII) compared to neutral (II, V, VIII) and valgus knees (III, VI, IX) (p<0.05 in all cases) as well as in the Distal Apex (I, II, III) compared to Neutral groups (IV, V, VI) (p<0.05 in all cases). Comparisons could not be made with the Proximal Apex groups due to low frequency (≤2.5%). Significant differences in joint balance were observed between and within CPAK groups. Although both hip-knee-ankle angle and joint line orientation are associated with joint balance, boney anatomy alone is not sufficient to fully characterize the knee

Standard fixation for intra-articular distal humerus fracture is open reduction and internal fixation (ORIF). However, high energy fractures of the distal humerus are often accompanied with soft tissue injuries and or vascular injuries which limits the use of internal fixation. In our report, we describe a highly complex distal humerus fracture that showed promising healing via a ring external fixator. A 26-year-old man sustained a Gustillo Anderson Grade IIIB intra-articular distal humerus fracture of the non-dominant limb with bone loss at the lateral column. The injury was managed with aggressive wound debridement and cross elbow stabilization via a hinged ring external fixator. Post operative wound managed with foam dressing. Post-operatively, early controlled mobilization of elbow commenced. Fracture union achieved by 9 weeks and frame removed once fracture united. No surgical site infection or non-union observed throughout follow up. At 2 years follow up, flexion - extension of elbow is 20°- 100°, forearm supination 65°, forearm pronation 60° with no significant valgus or varus deformity. The extent of normal anatomic restoration in elbow fracture fixation determines the quality of elbow function with most common complication being elbow stiffness. Ring fixator is a non-invasive external device which provides firm stabilization of fracture while allowing for adequate soft tissue management. It provides continuous axial micro-movements in the frame which promotes callus formation while avoiding translation or angulation between the fragments. In appropriate frame design, they allow for early rehabilitation of joint where normal range of motion can be allowed in controlled manner immediately post-fixation. Functional outcome of elbow fracture from ring external fixation is comparable to ORIF due to better rehabilitation and lower complications. Ring external fixator in our patient achieved acceptable functional outcome and fracture alignment meanwhile the fracture was not complicated with common complications seen in ORIF. In conclusion, ring external fixator is as effective as ORIF in treating complex distal humeral fractures and should be considered for definitive fixation in such fractures

The Bernese periacetabular osteotomy (PAO) is not indicated for growing hips as it crosses the triradiate cartilage in its posterior branch, and experimental work has shown this can induce substantial deformations, similar to posttraumatic dysplasia, which is observed after pelvis crash injuries in childhood. Upon examination, all injuries in the 19 cases of posttraumatic dysplasia described in literature plus 16 hips of our personal collection took place before the age of 6, which is striking as pelvic injuries in children increase with age. Based on this observation, we started to extend the PAO indication to severe dysplasias in children with open growth plate, initially aged 9 years and older. Following the positive results, it was extended further, our youngest patient being 5 years old. We retrospectively examined radiographic outcomes of 23 hips (20 patients), aged 10.6±1.8 years [range 5.0 – 13.2], operated by us in four centers. Pre- and 3-months postoperative, and the latest FUP radiograph at growth plate closure were measured. We evaluated the acetabular index (AI), lateral center-edge (LCE), ACM-value and compared them with reference values adjusted for age. The age at triradiate cartilage closure was compared with the non-operated side. The follow-up time was 5.4±3.7 years [0.8 - 12.7]. In 5 hips, growth plate closure was delayed by a few months. All angles significantly normalized after PAO (LCE: 14±8° → 38±11°, AI: 20±8° → 7±4°, ACM: 53±5° → 48±4°), with >80% of them severe pathological pre-PAO, none afterwards. Acetabular molding was normal. Only few complications occurred; one had signs of coxarthosis, one sciatic nerve pain, one interfering osteosynthesis material that was removed, one had an additional valgus osteotomy, and all resolved. Based on 20 cases with follow-up until complete triradiate cartilage closure, we believe to have sufficient information to extend the PAO indication to growing hips of 9 years and older

Background. Authors sought to determine the degree of lateral condylar hypoplasia of distal femur was related to degree of valgus malalignment of lower extremity in patients who underwent TKA. Authors also examined the relationships between degree of valgus malalignment and degree of femoral anteversion or tibial torsion. Methods. This retrospective study included 211 patients (422 lower extremities). Alignment of lower extremity was determined using mechanical tibiofemoral angle (mTFA) measured from standing full-limb AP radiography. mTFA was described positive value when it was valgus. Patients were divided into three groups by mTFA; more than 3 degrees of valgus (valgus group, n = 31), between 3 degrees of valgus to 3 degrees of varus (neutral group, n = 78), and more than 3 degrees of varus (varus group, n = 313). Condylar twisting angle (CTA) was used to measure degree of the lateral femoral condylar hypoplasia. CTA was defined as the angle between clinical transepicondylar axis (TEA) and posterior condylar axis (PCA). Femoral anteversion was measured by two methods. One was the angle formed between the line intersecting femoral neck and the PCA (pFeAV). The other was the angle formed between the line intersecting femoral neck and clinical TEA (tFeAV). Tibial torsion was defined as a degree of torsion of distal tibia relative to proximal tibia. It was determined by the angle formed between the line connecting posterior cortices of proximal tibial condyles and the line connecting the most prominent points of lateral and medial malleolus. Positive values represented relative external rotation. Negative values represented relative internal rotation. Results. Greater lateral femoral condylar hypoplasia was related to increased valgus alignment of lower extremity. Correlation coefficient between mTFA and CTA was 0.253 (p < 0.001). Valgus group showed increased CTA, which was 10.2° ± 1.9°. CTA was 7.4° ± 2.5° in neutral group and 6.6° ± 4.8° in varus group. There was significant positive correlation between the degree of valgus alignment and the degree of femoral anteversion (r = 0.145, p = 0.003). pFeAV was 16.7° ± 5.8° in valgus group, 12.1° ± 6.0° in neutral group and 10.9° ± 7.0° in varus group. There was no correlation between degree of valgus alignment and degree of femoral anteversion (r = 0.060, p = 0.218). In terms of tibial torsion, increased valgus malalignment was associated with increased tibial torsion (r = 0.374, p < 0.001). Valgus group showed increased tibial torsion than other groups. Tibial torsion was 32.6° ± 6.2° in valgus group, 26.3° ± 6.9° in neutral group and 22.6° ± 7.2° in varus group. Conclusions. Increased valgus alignment of lower extremity was related to greater lateral femoral condylar hypoplasia. However, increased valgus alignment was not related to degree of femoral anteversion whereas it was related to increased external tibial torsion. Our findings should be considered when determining proper rotational alignment in TKA

INTRODUCTION. Mechanical alignment in TKA introduces significant anatomic modifications for many individuals, which may result in unequal medial-lateral or flexion-extension bone resections. The objective of this study was to calculate bone resection thicknesses and resulting gap sizes, simulating a measured resection mechanical alignment technique for TKA. METHODS. Measured resection mechanical alignment bone resections were simulated on 1000 consecutive lower limb CT-Scans from patients undergoing TKA. Bone resections were simulated to reproduce the following measured resection mechanical alignment surgical technique. The distal femoral and proximal tibial cuts were perpendicular to the mechanical axis, setting the resection depth at 8mm from the most distal femoral condyle and from the most proximal tibial plateau (Figure 1). If the resection of the contralateral side was <0mm, the resection level was increased such that the minimum resection was 0mm. An 8mm resection thickness was based on an implant size of 10mm (bone +2mm of cartilage). Femoral rotation was aligned with either the trans-epicondylar axis or with 3 degrees of external rotation to the posterior condyles. After simulation of the bone cuts, media-lateral gap difference and flexion-extension gaps difference were calculated. The gap sizes were calculated as the sum of the femoral and tibial bone resections, with a target bone resection of 16mm (+ cartilage corresponding to the implant thickness). RESULTS. For both the varus and valgus knees, the created gaps in the medial and lateral compartments were reduced in the vast majority of cases (<16mm). The insufficient lateral condyle resection distalises the lateral joint surface by a mean of 2.1mm for the varus and 4.4mm for the valgus knees. The insufficient medial tibial plateau resection proximalises the medial joint surface by 3.3mm for the varus and 1.2mm for the valgus knees. Medio-lateral gap imbalances in the extension space of more than 2mm) occurred in 25% of varus and 54% of valgus knees and significant imbalances of more than 5mm were present in up to 8% of varus and 19% of valgus knees. Higher medio-lateral gap imbalances in the flexion space were created with trans epicondylar axis versus 3 degrees to the posterior condyles (p<0.001). Using trans epicondylar axis, only 49% of varus and 18% of valgus knees had less than 3mm of imbalance in both media-lateral and flexion-extension gaps together. DISCUSSION AND CONCLUSION. A systematic use of the tested measured resection mechanical alignment technique for TKA leads to many cases with medio-lateral or flexion-extension gap asymmetries. Some medio-lateral imbalances may not be correctable surgically and may results in TKA instability. Other versions of the mechanical alignment technique or other alignment methods that better reproduce knee anatomies should be explored. For any figures or tables, please contact the authors directly

Management of a knee with valgus deformities has always been considered a major challenge. Total knee arthroplasty requires not only correction of this deformity but also meticulous soft tissue balancing and achievement of a balanced rectangular gap. Bony deformities such as hypoplastic lateral condyle, tibial bone loss, and malaligned/malpositioned patella also need to be addressed. In addition, external rotation of the tibia and adaptive metaphyseal remodeling offers a challenge in obtaining the correct rotational alignment of the components. Various techniques for soft tissue balancing have been described in the literature and use of different implant options reported. These options include use of cruciate retaining, sacrificing, substituting and constrained implants. Purpose. This presentation describes options to correct a severe valgus deformity (severe being defined as a femorotibial angle of greater than 15 degrees) and their long term results. Methods. 34 women (50 knees) and 19 men (28 knees) aged 39 to 84 (mean 74) years with severe valgus knees underwent primary TKA by a senior surgeon. A valgus knee was defined as one having a preoperative valgus alignment greater than 15 degrees on a standing anteroposterior radiograph. The authors recommend a medial approach to correct the deformity, a minimal medial release and a distal femoral valgus resection of angle of 3 degrees. We recommend a sequential release of the lateral structures starting anteriorly from the attachment of ITB to the Gerdy's tubercle and going all the way back to the posterolaetral corner and capsule. Correctability of the deformity is checked sequentially after each release. After adequate posterolateral release, if the tibial tubercle could be rotated past the mid-coronal plate medially in both flexion and extension, it indicated appropriate soft tissue release and balance. Fine tuning in terms of final piecrusting of the ITB and or popliteus was carried out after using the trial components. Valgus secondary to an extra-articular deformity was treated using the criteria of Wen et al. In our study the majority of severe valgus knees (86%) could be treated by using unconstrained (CR, PS) knee options reserving the constrained knee / rotating hinge options only in cases of posterolateral instability secondary to an inadequate large release or in situations with very lax or incompetent MCL. Results. The average follow up was 10 years (range 8 to 14 years). The average HSS knee scores improved from 48 points preoperatively (range 32 to 68 points) to 91 points (range 78 to 95 points) postoperatively. The average postoperative range of motion measured with a goniometer was 110 degrees (range 80 to 135 degrees) which was a significant improvement over the preoperative levels (average 65 degrees). None of the patients were clinically unstable in the medioloateral or anteroposterior plane at the time of final follow up. The average preoperative valgus tibiofemoral alignment was 19.6 degrees (range 15 degrees to 45 degrees). Postoperatively the average tibio-femoral alignment was 5 degrees (range 2 degrees to 7 degrees) of valgus. No patient in the study was revised. Conclusion. Adequate lateral soft tissue release is the key to successful TKA in valgus knees. The choice of implant depends on the severity of the valgus deformity and the extent of soft tissue release needed to obtain a stable knee with balanced flexion and extension gaps. The most minimal constraint needed to achieve stability and balance was used in this study. In our experience the long term results of TKR on severe valgus deformities using minimal constrained knee have been good

For many years, achieving a neutral coronal Hip-Knee-Ankle angle (HKA) measured on radiographs has been considered a factor of success for total knee arthroplasty (TKA). Lower limb HKA is influenced by the acquisition conditions, and static HKA (sHKA) may not be representative of the dynamic loading that occurs during gait. The primary aim of the study was to see if the sHKA is predictive of the dynamic HKA (dHKA). A secondary aim was to document to what degree the dHKA changes throughout gait. We analysed the 3-D knee kinematics during gait of a cohort of 90 healthy individuals (165 knees) with the KneeKG™ system. dHKA was calculated and compared with sHKA values. Knees were considered “Stable” if the dHKA remained positive or negative – i.e. in valgus or varus – for greater than 95% of the corresponding phase and “Changer” otherwise. Patient characteristics of the Stable and Changer knees were compared to find contributing factors. The dHKA absolute variation during gait was 10.9±5.3° [2 .4° – 28.3°] for the whole cohort. The variation was greater for the varus knees (10.3±4.8° [2.4° – 26.3°]), than for the valgus knees (12.8±6.1° [2.9° – 28.3°], p=0.008). We found a low to moderate correlation (r = 0.266 to 0.553, p < 0 .001) between sHKA and the dHKA values for varus knees and no correlation valgus knees. Twenty two percent (36/165) of the knees demonstrated a switch in the dHKA (Changer). Proportion of Changer knees was 15% for varus sHKA versus 39% for valgus sHKA (p < 0.001). Lower limb radiographic measures of coronal alignment have limited value for predicting dynamic measures of alignment during gait

Aims. Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon. Methods. A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records. Results. A total of 243 hips (205 patients (163 male, 80 female; mean age at surgery 55.3 years (range 25.7 to 75.3)) with MoM-HRA performed between April 2003 and October 2020 were included. Mean follow-up was 11.2 years (range 0.3 to 17.8). Osteoarthritis was the most common indication (93.8%), and 13 hips (5.3%; 7M:6F) showed dysplasia (lateral centre-edge angle < 25°). Acetabular cups were implanted at a median of 45.4° abduction (interquartile range 41.9° - 48.3°) and stems neutral or valgus to the native neck-shaft angle. In all, 11 hips (4.5%; one male, ten females) in ten patients underwent revision surgery at a mean of 7.4 years (range 2.8 to 14.2), giving a cumulative survival rate of 94.8% (95% confidence interval (CI) 91.6% to 98.0%) at ten years, and 93.4% (95% CI 89.3% to 97.6%) at 17 years. For aseptic revision, male survivorship was 100% at 17 years, and 89.6% (95% CI 83.1% to 96.7%) at ten and 17 years for females. Increased metal ion levels were implicated in 50% of female revisions, with the remaining being revised for unexplained pain or avascular necrosis. Conclusion. The Birmingham MoM-HR showed 100% survivorship in males, exceeding the National Institute for Health and Care Excellence ‘5% at ten years’ threshold. Female sex and small component sizes are independent risk factors. Dysplasia alone is not a contraindication to resurfacing. Cite this article: Bone Jt Open 2023;4(11):853–858

Total shoulder arthroplasty (TSA) is an effective treatment for end-stage glenohumeral arthritis. The use of high modulus uncemented stems causes stress shielding and induces bone resorption of up to 63% of patients following TSA. Shorter length stems with smaller overall dimensions have been studied to reduce stress shielding, however the effect of humeral short stem varus-valgus positioning on bone stress is not known. The purpose of this study was to quantify the effect of humeral short stem varus-valgus angulation on bone stresses after TSA. Three dimensional models of eight male cadaveric humeri (mean±SD age:68±6 years) were created from computed tomography data using MIMICS (Materialise, Belgium). Separate cortical and trabecular bone sections were created, and the resulting bone models were virtually reconstructed three times by an orthopaedic surgeon using an optimally sized short stem humeral implant (Exactech Preserve) that was placed directly in the center of the humeral canal (STD), as well as rotated varus (VAR) or valgus (VAL) until it was contacting the cortex. Bone was meshed using a custom technique which produced identical bone meshes permitting the direct element-to-element comparison of bone stress. Cortical bone was assigned an elastic modulus of 20 GPa and a Poisson's ratio of 0.3. Trabecular bone was assigned varying stiffness based on CT attenuation. A joint reaction force was then applied to the intact and reconstructed humeri representing 45˚ and 75˚ of abduction. Changes in bone stress, as well as the expected bone response based on change in strain energy density was then compared between the intact and reconstructed states for all implant positions. Both varus and valgus positioning of the humeral stem altered both the cortical and trabecular bone stresses from the intact states. Valgus positioning had the greatest negative effect in the lateral quadrant for both cortical and trabecular bone, producing greater stress shielding than both the standard and varus positioned implant. Overall, the varus and standard positions produced values that most closely mimicked the intact state. Surprisingly, valgus positioning produced large amounts of stress shielding in the lateral cortex at both 45˚ and 75˚ of abduction but resulted in a slight decrease in stress shielding in the medial quadrant directly beneath the humeral resection plane. This might have been a result of direct contact between the distal end of the implant and the medial cortex under loading which permitted load transfer, and therefore load-reduction of the lateral cortex during abduction. Conversely, when the implant was placed in the varus angulation, noticeable departures in stress shielding and changes in bones stress were not observed when compared to the optimal STD position. Interestingly, for the varus positioned implant, the deflection of the humerus under load eliminated the distal stem-cortex contact, hence preventing distal load transfer thus precluding the transfer of load

Abstract. Background. Distal femoral osteotomy is an established successful procedure which can delay the progression of arthritis and the need for knee arthroplasty. The surgery, however, is complex and lengthy and consequently it is generally the preserve of highly experienced specialists and thus not widely offered. Patient specific instrumentation is known to reduce procedural complexity, time, and surgeons’ anxiety levels. 1. in proximal tibial osteotomy procedures. This study evaluated a novel patient specific distal femoral osteotomy procedure (Orthoscape, Bath, UK) which aimed to use custom-made implants and instrumentation to provide a precision correction while also simplifying the procedure so that more surgeons would be comfortable offering the procedure. Presenting problem. Three patients (n=3) with early-stage knee arthritis presented with valgus malalignment, the source of which was predominantly located within the distal femur, rather than intraarticular. Using conventional techniques and instrumentation, distal femoral knee osteotomy cases typically require 1.5–2 hours surgery time. The use of bi-planar osteotomy cuts have been shown to improve intraoperative stability as well as bone healing times. 2. This normally also increases surgical complexity; however, multiple cutting slots can be easily incorporated into patient specific instrumentation. Clinical management. All three cases were treated at a high-volume tertiary referral centre (Istituto Ortopedico Rizzoli, Bologna) using medial closing wedge distal femoral knee osteotomies by a team experienced in using patient specific osteotomy systems. 3. Virtual surgical planning was conducted using CT-scans and long-leg weight-bearing x-rays (Orthoscape, Bath, UK). Patient specific surgical guides and custom-made locking plates were design for each case. The guides were designed to allow temporary positioning, drilling and bi-planar saw-cutting. The drills were positioned such that the drills above and below the osteotomy became parallel on closing following osteotomy wedge removal. This gave reassurance of the achieved correction allowed the plate to be located precisely over the drills. All screw lengths were pre-measured. Discussion. The surgical time reduced to approximately 30 minutes by the third procedure. It was evident that surgical time was saved because no intraoperative screw length measurements were required, relatively few x-rays were used to confirm the position of the surgical guide, and the use of custom instrumentation significantly reduced the surgical inventory. The reduced invasiveness and ease of surgery may contribute to faster patient recovery compared to conventional techniques. The final post-operative alignment was within 1° of the planned alignment in all cases. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest