Aims. The integrity of the soft tissue envelope is crucial for successful treatment of infected total knee arthroplasty (TKA). The purpose of this study was to evaluate the rate of limb salvage, infection control, and clinical function following microvascular free flap coverage for salvage of the infected TKA. Methods. We retrospectively reviewed 23 microvascular free tissue transfers for management of soft tissue defects in infected TKA. There were 16 men and seven women with a mean age of 61.2 years (39 to 81). The median number of procedures performed prior to soft tissue coverage was five (2 to 9) and all patients had failed at least one two-stage reimplantation procedure. Clinical outcomes were measured using the Knee Society Scoring system for pain and function. Results. In all, one patient was lost to follow-up prior to 12 months. The remaining 22 patients were followed for a mean of 46 months (12 to 92). At latest follow-up, four patients (18%) had undergone amputation for failure of treatment and persistent infection. For the other 18 patients, 11 patients (50%) had maintained a knee prosthesis in place while seven patients had undergone resections for persistent infection but retained their limbs (32%). Reoperations were common following coverage and reimplantation. The median number of additional procedures was two (0 to 6). Clinical function was poor in patients who underwent reimplantation and retained a knee prosthesis following free flap coverage with a mean KSS score for pain and function of 44 (0 to 70) and 30 (0 to 65), respectively. All patients required an assistive device. Extensor mechanism problems and extensor lag requiring bracing were common following limb salvage and prosthesis reimplantation. Conclusion. Microvascular tissue transfer for management of infected TKA can be successful in limb salvage (82%) but clinical outcomes in salvaged limbs were poor. Cite this article: Bone Joint J 2020;102-B(6 Supple A):176–180

Aims. What represents clinically significant acetabular undercoverage in patients with symptomatic cam-type femoroacetabular impingement (FAI) remains controversial. The aim of this study was to examine the influence of the degree of acetabular coverage on the functional outcome of patients treated arthroscopically for cam-type FAI. Patients and Methods. Between October 2005 and June 2016, 88 patients (97 hips) underwent arthroscopic cam resection and concomitant labral debridement and/or refixation. There were 57 male and 31 female patients with a mean age of 31.0 years (17.0 to 48.5) and a mean body mass index (BMI) of 25.4 kg/m. 2. (18.9 to 34.9). We used the Hip2Norm, an object-oriented-platform program, to perform 3D analysis of hip joint morphology using 2D anteroposterior pelvic radiographs. The lateral centre-edge angle, anterior coverage, posterior coverage, total femoral coverage, and alpha angle were measured for each hip. The presence or absence of crossover sign, posterior wall sign, and the value of acetabular retroversion index were identified automatically by Hip2Norm. Patient-reported outcome scores were collected preoperatively and at final follow-up with the Hip Disability and Osteoarthritis Outcome Score (HOOS). Results. At a mean follow-up of 2.7 years (1 to 8, . sd. 1.6), all functional outcome scores significantly improved overall. Radiographically, only preoperative anterior coverage had a negative correlation with the improvement of the HOOS symptom subscale (r = -0.28, p = 0.005). No significant difference in relative change in HOOS subscale scores was found according to the presence or absence of radiographic signs of retroversion. Discussion. Our study demonstrated the anterior coverage as an important modifier influencing the functional outcome of arthroscopically treated cam-type FAI. Cite this article: Bone Joint J 2018;100-B:831–8

Aims. Ganz’s studies made it possible to address joint deformities on both the femoral and acetabular side brought about by Perthes’ disease. Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency, along with periacetabular osteotomy (PAO), which may enhance coverage and containment. The purpose of this study is to show the clinical and morphological outcomes of the technique and the use of an implemented planning approach. Methods. From September 2015 to December 2021, 13 FHROs were performed on 11 patients for Perthes’ disease in two centres. Of these, 11 hips had an associated PAO. A specific CT- and MRI-based protocol for virtual simulation of the corrections was developed. Outcomes were assessed with radiological parameters (sphericity index, extrusion index, integrity of the Shenton’s line, lateral centre-edge angle (LCEA), Tönnis angle), and clinical parameters (range of motion, visual analogue scale (VAS) for pain, Merle d'Aubigné-Postel score, modified Harris Hip Score (mHHS), and EuroQol five-dimension five-level health questionnaire (EQ-5D-5L)). Early and late complications were reported. Results. The mean follow-up was 39.7 months (standard deviation (SD) 26.4). The mean age at surgery was 11.4 years (SD 1.6). No major complications were recorded. One patient required a total hip arthroplasty. Mean femoral head sphericity increased from 46.8% (SD 9.34%) to 70.2% (SD 15.44; p < 0.001); mean LCEA from 19.2° (SD 9.03°) to 44° (SD 10.27°; p < 0.001); mean extrusion index from 37.8 (SD 8.70) to 7.5 (SD 9.28; p < 0.001); and mean Tönnis angle from 16.5° (SD 12.35°) to 4.8° (SD 4.05°; p = 0.100). The mean VAS improved from 3.55 (SD 3.05) to 1.22 (1.72; p = 0.06); mean Merle d’Aubigné-Postel score from 14.55 (SD 1.74) to 16 (SD 1.6; p = 0.01); and mean mHHS from 60.6 (SD 18.06) to 81 (SD 6.63; p = 0.021). The EQ-5D-5L also showed significant improvements. Conclusion. FHRO associated with periacetabular procedures is a safe technique that showed improved functional, clinical, and morphological outcomes in Perthes’ disease. The newly introduced simulation and planning algorithm may help to further refine the technique. Cite this article: Bone Joint J 2024;106-B(5 Supple B):40–46

The current study aimed to determine the influence of acetabular coverage and intraarticular pathology on post-operative functional outcomes of arthroscopy for cam type FAI. Based on 762 hip scopes performed by a single surgeon between 2013 and 2016, we excluded patients with previous surgery on the hip, mixed FAI, surgical hip dislocation, and missing outcome scores. From this, 97 hips between the ages 17 and 48 that underwent arthroscopy for cam deformity were identified for analysis. Every patient received a partial capsulotomy, cam resection and either labral repair or resection. Measurements for acetabular coverage consisted of pre-operative lateral edge angle (LCEA) (mean 30°, range: 15.4°–40°) and three-dimensional anterior and posterior acetabular coverages. Intraoperative Beck scores were acquired from operative reports, and Hip Disability and Osteoarthritis Outcome Score (HOOS) was collected pre- and post-operatively. Significant post-operative improvement was found in scores of all categories of the HOOS (p < 0.05). However, improvement in HOOS was not correlated with the LCEA, anterior coverage, or posterior coverage. There was a trend toward lower Beck grades (1–3) resulting in better HOOS outcomes than higher Beck grades (4–5). Also, lower Beck grades showed significantly lower alpha angle (mean = 55.86) than higher grades (mean = 73.48). We showed that cam FAI arthroscopic resection improved patient outcome, and confirmed the relationship between the Beck score and functional outcome. However, functional improvement was not related to acetabular coverage suggesting that the so-called “borderline” dysplasia is not a useful radiographic indicator for surgical management

Introduction. Bernese periacetabular osteotomy (PAO) repositions the acetabulum to increase femoral head coverage (FHC) in hip dysplasia. Currently, there is a paucity of objective peri-operative metrics to plan for optimal acetabular fragment repositioning. The MSk Lab Hip 3D Planner (MSkL-HP) measures acetabular morphology and simulates PAO cuts to achieve optimal FHC. We evaluated how adjusting location and orientation of cutting planes can alter FHC. Method. MSkL-HP simulated 274 feasible PAOs on four dysplastic hips. Femoroacetabular anatomy was landmarked to simulate cutting planes. Posterior column and ischial cuts were standardised, whilst iliac and pubic cut combinations varied. The slope of the iliac cut was either neutral (aligned to pelvis), exit point 5mm above the entry point (+5), or 5mm below (-5). The slope of the pubic cut was either 90°, 50°, or 70° (medial-to-lateral). Iliac and pubic cuts were simulated 0, 5 and 15mm - distal and medial – to a classic cut. Outcome measures were achieved LCEA, Tönnis, FHC and % bone overlap at the pubic cut. Targets were LCEA >30°, Tönnis angle <10°, and FHC >70% and minimum bone overlap ≥10%. Results. All feasible PAOs resulted in improvement from pre-operative metrics. Personalised cutting planes provided greater benefit than standard planes. Kruskal Wallis tests showed that the iliac cut at 5mm or 15mm resulted in a greater LCEA and lower Tönnis compared to the classic cut (p<0.05). Changing location of the pubic cut, and slope of the iliac and pubic cuts did not significantly affect LCEA and Tönnis in all hips (p<0.05). Cut combinations optimising metrics were associated with a lower % pubic cut overlap. Conclusion. MSkL-HP feasibly and reliably planned personalised PAO, measuring pre-operative and simulated post-operative objective metrics. Patient-specific pubic and iliac cuts enable greater correction whilst maintaining bone overlap. Further simulations on patients with varying morphology may improve standard techniques

INTRODUCTION:. Successful tibial component placement during total knee arthroplasty (TKA) entails accurate rotational alignment, minimal overhang, and good bone coverage, each of which can be facilitated with a tibial component that matches the resected tibial surface. Previous studies investigated bony coverage of multiple tibial component families on digitized resections. However, these studies were based on manual placement of the component that may lead to variability in overhang and rotational alignment. An automated simulation that follows a consistent algorithm for tibial component placement is desirable in order to facilitate direct comparison between tibia component designs. A simulation has been developed and applied to quantify tibial coverage in multiple ethnicities, including Japanese, Indian, and Caucasian. Here, this approach is taken to evaluate tibial coverage of five contemporary tibial designs in Chinese subjects. METHODS:. Digital models of 100 healthy Chinese tibiae (50 male, 50 female; age 68 ± 3 years; stature 1.65 ± 0.10 m) were virtually resected at 5° posterior slope referencing the anterior border of the proximal tibia, 0° varus/valgus rotation referencing the tibial mechanical axis, and 8 mm off the unaffected plateau (reflecting a 10 mm surgical cut, assuming a cartilage thickness of 2 mm). Neutral internal/external (I/E) alignment axis was derived from the medial third of the tubercle and the PCL attachment site. Five commercial tibial designs (Design A, Deluxe™, Montagne, Beijing, China; Designs B-E contemporary market-established symmetric designs from four US manufacturers) were virtually placed on the resected tibiae following an automated algorithm, which maximizes component size while ensuring proper rotational alignment (within 5° I/E) and minimizing overhang (<1 mm in zones 1–4, Fig 1). Tibial coverage (posterior notch excluded, zone 5 in Fig 1) and distance from the component to the exterior cortex of the tibia in four clinically relevant anatomical zones (anterior medial, anterior lateral, posterior medial, and posterior lateral, zones 1–4, Fig 1) were calculated. Statistical significance was defined at p < 0.05. RESULTS:. Coverage across designs varied between 75% and 96%. All five designs showed comparable means and standard deviations in tibial coverage (Fig. 2). Although statistically higher coverage was found in Designs D-E than Designs A-C (p < 0.04), the difference in means (86–87% for Designs A-C; 88% for both Designs D-E) was clinically not meaningful (Fig. 2). Design A was found to be slightly (0.67 mm, p = 0.02) farther away from the cortex than Design E in the anterior medial zone; no other significant differences were found for distance to cortex between any of the component designs in any of the anatomical zones (Fig. 3). DISCUSSION:. The data suggests comparable tibial coverage, which may reflect the likelihood for component subsidence clinically, is expected between the six contemporay design investigtated when implanted into Chinese patients. Though subsidence is multifactorial, and is dependent on aspects of implant design and surgical technique beyond just tibial tray shape, these results nevertheless provide initial indicators on the expected rate of subsidence or overhang in Chinese patients for Design A relative to the more established Designs B-E

Introduction. Infection following TKA can be a catastrophic complication that can cause significant pain, morbidity and jeopardize limb viability. The integrity of the soft tissue envelope is critical to successful treatment and infection control. While local tissue flaps can provide adequate coverage for most soft tissue defects around the knee, there are cases that require salvage using microvascular free tissue transfers. The purpose of this study is to evaluate the 1) rate of limb salvage; 2) infection control; and 3) clinical function following free flap coverage for salvage of the infected TKA. Materials and Methods. We retrospectively reviewed 23 microvascular free tissue transfers for management of soft tissue defects in infected TKA. There were 16 men and 7 women with a mean age of 61.2 years (range 39–81). The median number of procedures performed prior to soft tissue coverage was 5 (range 2–9) and all patients had failed at least one 2 stage reimplantation procedure. Clinical outcomes were measured using the Knee Society Scoring system for pain and function. The rate of limb salvage and infection control were recorded. Results. One patient was lost to follow up prior to 12 months. The remainder 22 patients were followed for a mean of 46 months (range 12–92 months). At latest follow up, 4 patients (18%) had undergone amputation for failure of treatment and persistent infection. For the remainder 18 patients, 11 patients (50%) have maintained a knee prosthesis in place while 7 patients had undergone resections for persistent infection but maintained their limbs (32%). Reoperations were common following coverage and reimplantation procedure. The median number of additional procedures was 2 (range 0–6). Clinical function was poor in patients who were reimplanted and retained a knee prosthesis following free flap coverage with a mean KSS score for pain and function of 44 (range 0–70) and 30 (range 0–65). All patients required an assistive device. Extensor mechanism problems and extensor lag requiring bracing were common following limb salvage and prosthesis reimplantation. Conclusions. Microvascular tissue transfer for management of infected TKA can be successful in limb salvage (81%) but clinical outcomes in salvaged limbs were poor. The data should be used to counsel patients when contemplating limb salvage in these severe, end-stage cases. For figures, tables, or references, please contact authors directly

Introduction:. Adequate coverage of the resected tibial plateau with the tibial tray is necessary to reduce the theoretical risk of tibial subsidence after primary total knee arthroplasty (TKA). Maximizing tibial coverage is balanced against avoiding excessive overhang of the tray causing soft tissue irritation, and establishing proper tray alignment improving implant longevity and patella function. 1. Implant design factors, including the number of tray sizes, tray shape, and tray asymmetry influence the ability to cover the tibial plateau. 2. Furthermore, rotating platform (RP) tray designs decouple restoring proper tibial rotation from maximizing tibial coverage, which may enhance the ability to maximize coverage. The purpose of the current study was to assess the ability of five modern tray designs (Fig. 1), including symmetric, asymmetric, fixed-bearing, and RP designs, to maximize coverage of the tibial plateau across a large patient population. Methods:. Lower limb computed-tomography scans were collected from 14,791 TKA patients and the tibia was segmented. Virtual surgery was performed with an 8-mm tibial resection (referencing the high side) made perpendicular to the tibial mechanical axis in the frontal plane, with 3° posterior slope, and aligned transversely to the medial third of the tibial tubercle. An automated algorithm placed the largest possible tray on the plateau, optimizing the ML and AP placement (and I-E rotation for the RP tray), to minimize overhang. The largest sized tray that fit the plateau with less than 2-mm of tray overhang was identified for each of the five implant systems. The surface area of the tibial tray was divided by the area of the resected plateau and the percentage of patients with greater than 85% plateau coverage was calculated. Results:. The percentage of patients with greater than 85% plateau coverage across the tray designs ranged from 17.0% to 61.4% (Fig. 1). The tray with the greatest number of size options (Tray 4, 10 sizes) had the best coverage among the fixed-bearing trays. The RP variant of the same tray had the best overall coverage. Tibial asymmetry did not significantly improve the overall tibial coverage across the patient distribution for both asymmetric designs. Incorporating a broader medial condyle improved fit along the posterior medial corner for Tray 2, but increased the average under-hang along the posterior lateral plateau offsetting any improvement in total coverage. Discussion:. This analysis represents the most comprehensive assessment of tray coverage to date across a large TKA-patient population. Large variations exist in the size and shape of the proximal tibia among TKA patients. 3. Developing a tray design which provides robust coverage despite this variation remains challenging. This analysis suggests that tibial asymmetry may not robustly improve coverage. Conversely, incorporating an increased number of tray sizes and utilizing an RP implant to decouple coverage from alignment may provide the most reliable solution for maximizing coverage across the patient population

INTRODUCTION:. Recent trends in total hip arthroplasty (THA) have resulted in the use of larger acetabular components to achieve larger femoral head sizes to reduce dislocation, and improve range of motion and stability. Such practices can result in significant acetabular bone loss at the time of index THA, increasing risk of anterior/posterior wall compromise, reducing component coverage, component fixation, ingrowth surface and bone stock for future revision surgery. We report here on the effects of increasing acetabular reaming on component coverage and bone loss in a radiographic CT scan based computer model system. METHODS:. A total of 74 normal cadaveric pelves with nonarthritic hip joints underwent thin slice CT scan followed by upload of these scans into the FDA approved radiographic analysis software. Utilizing this software package, baseline three-dimensional calculations of femoral head size and acetabular size were obtained. The software was used to produce a CT scan based model that would simulate reaming and placement of acetabular components in these pelves that were 125, 133 and 150% the size of the native femoral head. Calculations were made of cross sectional area bone loss from anterior/posterior columns, and loss of component coverage with increasing size. RESULTS:. Use of acetabular components that were 125, 133 and 150% the size of the native femoral head led to a average loss of 23, 27% and 33% loss of cross-sectional acetabular bone and an average 7, 16 and 27% loss of acetabular component coverage. CONCLUSION:. The CT scan/computer based model described here demonstrates that acetabular preparation and use of large components simply to gain larger femoral head size can result in significant bone loss and reduced component coverage. Operating hip surgeons attempting to utilize such large components must take great caution when attempting to maximize acetabular component size

Introduction. Large numbers of patients with open tibial fractures are treated in our major trauma centre. Previously, immediate definitive skeletal stabilisation and soft tissue coverage has been recommended in the management of such injuries. We describe our recent practice, focusing on soft tissue cover, including patients treated by early soft tissue cover and delayed definitive skeletal stabilisation. Methods. Between September 2012 and January 2016, more than 120 patients with open tibial fractures were admitted to our unit. Patients were identified through prospective databases. Data collected included patient demographics, injury details, orthopaedic and plastic surgery procedures. Major complications were recorded. Paediatric cases were excluded and one patient was lost to follow up. Results. Fifty-seven patients (median age 41 years (range 16–95)) were identified with open tibial fractures classified grade IIIB or IIIC requiring soft tissue coverage. Of these 57 patients, 39 were treated by initial temporary external fixation, soft tissue cover, and circular frame and 18 by initial temporary external fixation, soft tissue cover and internal fixation (ORIF). Of the 57 patients, 51 were acutely managed by Leeds MTC, and 6 were tertiary referrals primarily managed elsewhere. Soft tissue cover constituted free tissue transfer in 43 patients (19 gracilis, 15 ALT, 6 LD, 2 radial forearm and 1 groin flap), pedicled flap in 12 patients (6 gastroc, 4 fasciocutaneous, 1 soleus, 1 EDB), and skin graft in 2 patients. Complications included flap failure (n=3), return to theatre (n=1). Long term soft tissue cover was definitely achieved in 100% of cases. Chronic deep infection was reported in 1 acutely managed case. There were no cases of soft tissue failure after delayed circular frame fixation following soft tissue reconstruction. Conclusions. Evolution of orthopaedic techniques has meant that the management of these complex fractures using delayed definitive fixation with a circular frame is increasingly commonplace. This case series demonstrates that a joint orthoplastic approach, with circular frame application undertaken a short time after soft tissue reconstruction (including free flap surgery) is safe and can be undertaken without risk to the soft tissue coverage

Dynamic 2D sonography of the infant hip is a commonly used clinical procedure for developmental dysplasia of the hip (DDH) screening. It however has been found to be unreliable with some studies reporting associated misdiagnosis rates of up to 29%. In a recent systematic review, Charlton et al. examined dynamic ultrasound (US) screening for hip instability in the first six weeks after birth and found current best practices for such early screening techniques to be divergent between international institutions in terms of clinical scanning protocols. Such protocols include: the appropriate scanning plane and US probe position (e.g. coronal, transverse, lateral, anterior), DDH diagnostic metrics (e.g. femoral head coverage, alpha angle), appropriate patient age when scanning, and follow up procedures. To improve reliability of diagnosis and to help in standardizing diagnosis across different raters and health-centers, we propose an automated method for dynamically assessing hip instability using 3D US. 38 infant hips from 19 patients were scanned with B-mode 3D US by a paediatric orthopaedic surgeon and two technologists from the radiology department at a paediatric tertiary care centre. To quantify hip assessment, we proposed the use of femoral head coverage variability (ΔFHC3D) within 3D US volumes collected during a sequence of US scans (one at rest, and another with posterior stress applied to the joint as maneuvered during a dynamic assessment). We used phase symmetry image features to localize the ilium's vertical cortex and a random forest classifier to identify the location of the femoral head. The proposed ΔFHC3D provided good repeatability with an average test-retest ICC measure of 0.70 (95% confidence interval: 0.35 to 0.87, F(21,21) = 7.738, p<.001). The mean difference of ΔFHC3D measurements was 0.61% with a SD of 4.05%. Since the observed changes in ΔFHC3D start near 0% and range up to about 18% from stable to mildly unstable hips in this cohort, the mean difference and standard deviation of ΔFHC3D measurements observed suggest that the proposed metric and technique likely have sufficient resolution and repeatability to quantify differences in hip laxity. The long-term significance of this approach to evaluating dynamic assessments may lie in increasing early diagnostic accuracy in order to prevent dysplasia remaining undetected prior to manifesting itself in early adulthood joint disease

To describe clinical situations for use of modified VAC in POC based on: diagnosis, comorbidities, BMI, wound size in cm, days following trauma when VAC was first applied, total duration of uninterrupted use, frequency of change, settings, bacterial growth, outcomes. To report the outcomes of mVAC use in POC within 6 months to help improve and standardize its application in the institution. This study involves data gathering from inpatients handled by orthopedic surgeons in training and subspecialty rotations in POC. The data collected are highly dependent on the doctors-in-charge's complete charting, thorough reporting and accurate documentation. Modified Vacuum Assisted Closure (mVAC) is used frequently in this study and is defined as a form of revised, adapted and reformed use of VAC based on available materials in the involved institution. The materials that are included are, but not limited to the following: sterile Uratex™ blue foam, nasogastric or suction tubing, phlegm suction machine, Bactigras™ and Opsite™ or Ioban™. A total of 58 patients were included in the study. The average age of the population was 35 and are predominantly male. The most common mechanism of injury was motorcycle accident and 37 of the patients were diagnosed with an open fracture of the lower extremity with open tibia fractures (22) being the most common. Average wound area measured was 24.12 cm. 3. All patients yield a bacteria growth with e. coli being the most frequent. Average during of uninterrupted use was 39 days. Of the 58 included in the study, 8 patients underwent STSG, 2 had a flap coverage surgery, 4 patients eventually underwent amputation and 33 with complete resolution of soft tissue defect after conversion to biologic dressing post-mVAC. The rest of the population were still ongoing mVAC at the end of the study. mVAC is an alternative temporary medium for soft tissue coverage for cases with or without concomitant fractures. mVAC promotes removal of exudate from the wound, supports wound apposition and granulation bed proliferation. Usage mVAC helps prepare for skin coverage procedure and on some cases leads to full resolution of defect

Introduction: A criticism of innominate osteotomy is that it causes relative acetabular retroversion, predisposing to osteoarthritis. This study was designed to address this hypothesis. Materials and Methods: We had access to radiographs of 30 patients that had undergone open reduction and innominate osteotomy for late presenting developmental hip dislocation. The patients are now middle-aged and formed part of a previously reported study. Standardised, well-centered anteroposterior standing hip radiographs were obtained and using the validated method of Hefti (1995), anterior and posterior acetabular coverage and contact area were measured. From this we were able to extrapalate the acetabular version. Ten operated hips had advanced osteoarthritis which made it impossible to identify acetabular landmarks. Twenty-six hips were readable despite signs of mild to moderate osteoarthritis in some (Group A). 20 contra-lateral hips without DDH which appeared radiographically normal formed control group B. 21 further age and sex matched AP pelvis radiographs were taken from the PACS system at random. All of which had been reported as normal by a consultant musculoskeletal radiologist, these formed group C. The Kruskal Wallis test was used to compare the 4 outcomes, in the 3 groups. A significant difference between the groups was found for contact area (p< 0.001). There was no significant difference between the other 3 outcomes. Anterior coverage (p=0.509), posterior coverage (p = 0.135) and antirversion (p= 0.845). Conclusion: Acetabular coverage and anteversion in hips with a good outcome after innominate osteotomy with open reduction were not different to a control group of radiographically normal hips without previous DDH. The early osteoarthritic changes seen in these hips may be related to a decreased contact area compared to the normal population. Innominate osteotomy before the age of 5 years has the potential to facilitate, or at least not prevent, normal acetabular development and version

Introduction. Several reports demonstrated the overcoverage of the anterior acetabulum. Anterior CE angle over 46°may be a probable risk factor for pincer FAI syndrome after a rotational acetabular osteotomy. In addition, a highly anteverted femoral neck, reported as a risk factor for posterior impingement, has been found in DDH patients. These findings indicate proper acetabular reorientation is essential to avoid anterior or posterior impingement after periacetabular osteotomy (PAO). The aim of this study was to evaluate the relationship between acetabular three-dimensional (3D) alignment reorientation and clinical range of motion (ROM) after periacetabular osteotomy (PAO). Methods. A total of 53 patients who underwent curved PAO (CPO) for DDH from January 2014 to April 2017 were selected. Three (5.7%) of them were lost to follow-up. Therefore, the data from 58 hips, contributed by 50 patients (44 women and 6 men), were included in the analysis. Pre- and postoperative computed tomography (CT) scans from the pelvis to the knee joint were performed and transferred to a 3D template software (Zed Hip; Lexi, Tokyo, Japan). The pelvic plane axis was defined according to the functional pelvic plane. The pre- and postoperative lateral and anterior 3D center-edge (CE) angles were measured on the coronal and sagittal views through the center of the femoral head. The pre- and postoperative 3D center-edge (CE) angles and femoral anteversion were measured and compared with clinical outcomes, including postoperative ROM. Results. The radiographical outcomes of our study are demonstrated in Figure 1. The mean values of pre- and postoperative lateral CE angles were 12.6º±8.7 and 30.2º±9.7, respectively (p<0.001), and mean pre- and postoperative anterior CE angles were 42.4º±15.3 and 63.9º±12.1, respectively (p<0.001). Both CE angles were significantly improved. The correlation between pre- and postoperative acetabular coverage and postoperative ROM was evaluated. Postoperative abduction and internal rotation ROM were significantly associated with postoperative lateral CE angles (abduction; p < 0.001, internal rotation; p = 0.028); flexion and internal rotation ROM was significantly associated with postoperative anterior CE angles (flexion; p < 0.001, internal rotation; p = 0.028). Femoral anteversion was negatively correlated with postoperative abduction (p = 0.017) and external rotation (p = 0.047) ROM (Table 1). Postoperative abduction ROM was strongly positively correlated with femoral anteversion, whereas postoperative external rotation was strongly negatively correlated (Table 2). The total anteversion was strongly correlated with pre- or postoperative ROMs during flexion and internal rotation ROM (Table 2). Conclusion. Postoperativeanterior acetabular coverage may affect internal rotation ROM more than the lateral coverage. Therefore, the direction of acetabular reorientation should be carefully determined according to 3D alignment during PAO. For any figures or tables, please contact the authors directly

Introduction: A criticism of innominate osteotomy (IO) is that it causes relative acetabular retroversion, predisposing to OA. This study was designed to address this hypothesis. Materials and Methods: We had access to radiographs of 30 patients 45 years after they had undergone open reduction and innominate osteotomy for late presenting DDH. Using the validated method of Hefti (1995) we measured anterior and posterior acetabular coverage, contact area and version. Results: Group 1 – 26 Post-op hips, Group 2 – 20 Contralateral hips, Group 3 – 21 Normal hips. Anterior coverage was 10.8% in group 1, 11.0% in group 2 and 12.0% in group 3. Posterior coverage was 18.8% in group 1, 18.9% in group 2 and 21.0% in group 3. Contact area was 16.1 cm2 in group 1, 13.9 cm2 in group 2, and 22.1 cm2 in group 3. Version was 7.20 in group 1, 7.10 in group 2, and 7.70 in group 3. A significant difference was found for contact area (p< 0.001). There was no significant difference in version (p = 0.845). Conclusion: Early OA may be related to contact area. Any abnormal (retro)version grows out. Innominate osteotomy before the age of 5 years has the potential to facilitate, or at least not prevent, normal acetabular development and version

Introduction: Assessing coverage of the femoral head is a crucial element in acetabular surgery for hip dysplasia. Radiographic indices give rather limited information. We present a novel ct-based method that gives an image of the head with the covered area precisely represented. We used this method to measure femoral head coverage in a series of normal hips and in a prospective study of patients with hip dysplasia undergoing peri-acetabular osteotomy. Methods: Thirteen normal and ten dysplastic hips were studied. On each CT scan anatomical landmarks were assigned on the 3d reconstructed image and used to define the frame of reference. Points were assigned on the femoral head surface and the superior half of the acetabular rim after aligning the pelvis in the anterior pelvic plane. An image was produced representing the femoral head and its covered part. The fraction of the head that was covered was calculated. Results: The average femoral head coverage in the normal hips was 73.9% (sd 3.2). The average coverage in the dysplastic group was 50.7% (sd 7.9) and after undergoing peri-acetabular osteotomy the average was 67% (sd 6.2). Conclusion: This is the first study to our knowledge that has used a reliable measurement technique to give an indication of the percent coverage of the femoral head by the acetabulum in the “normal hip”. When this is applied to assessing coverage in surgery to address hip dysplasia it gives a clearer understanding of where the corrected hip stands in relation to a normal hip, and this should allow for better determination of the likely outcome of this type of surgery

Introduction. The goal of tibial tray placement in total knee arthroplasty (TKA) is to maximize tibial surface coverage while maintaining proper rotation. Maximizing tibial surface coverage without component overhang reduces the risk of tibial subsidence. Proper tibial rotation avoids excess risk of patellar maltracking, knee instability, inappropriate tibial loading, and ligament imbalance. Different tibial tray designs offer varying potential in optimizing the relationship between tibial surface coverage and rotation. Patient specific instrumentation (PSI) generates customized guides from an MRI- or CT-based preoperative plan for use in TKA. The purpose of the present study was to utilize MRI information, obtained as part of the PSI planning process, to determine, for anatomic, symmetric, and asymmetric tibial tray designs, (1) which tibial tray design achieves maximum coverage, (2) the impact of maximizing coverage on rotation, and (3) the impact of establishing neutral rotation on coverage. Methods. In this prospective comparative study, MR images for 100 consecutive patients were uploaded into Materialise™ PSI software that was used to evaluate characteristics of tibial component placement. Tibial component rotation and surface coverage was analyzed using the preoperative planning software. Anatomic (Persona™), symmetric (NexGen™), and asymmetric (Natural-Knee II™) designs from a single manufacturer (Zimmer™) were evaluated to assess the relationship of tibial coverage and tibial rotation. Tibial surface coverage, defined as the proportion of tibial surface area covered by a given implant, was measured using Adobe Photoshop™ software (Figure 1). Rotation was calculated with respect to the tibial AP axis, which was defined as the line connecting the medial third of the tibial tuberosity and the PCL insertion. Results. When tibial surface coverage was maximized, the anatomic tray compared to the symmetric/asymmetric trays showed significantly higher surface coverage (82.1% vs 80.4/80.1%; p<0.01), significantly less deviation from the AP axis (0.3° vs 3.0/2.4°; p<0.01), and a significantly higher proportion of cases within 5° of the AP axis (97% vs 73/77%). When constraining rotation to the AP axis, the anatomic tray showed significantly higher surface coverage compared to the symmetric/asymmetric trays (80.8% vs 76.3/75.8%; p<0.01). No significant differences were found between symmetric and asymmetric trays. Discussion. We found that the anatomic tibial tray resulted in significantly higher tibial coverage with significantly less deviation from the AP axis compared to the symmetric and asymmetric trays. When rotation was constrained to the AP axis, the anatomic tray resulted in significantly higher tibial coverage than the symmetric and asymmetric trays. Tibial rotation is recognized as an important factor in the success of a total knee replacement. Maximizing coverage with the least compromise in rotation is the goal for tibial tray design. In this study, the anatomic tibia seemed to optimize the relationship between tibial surface coverage and rotation. This study additionally illustrates the way by which advanced preoperative planning tools (ie. MRI/computer reconstructions) allow us to obtain valuable information with regard to implant design

In this paper operations are discussed that improve the dysplastic acetabular roof in developmental dislocation of the hip (DDH) of children up to 10 years. In the first year of life acetabular dysplasia can be treated successfully by flexion-abduction splints and plaster casts in „human position“. From the second year on, only slight dysplasias can heal spontaneously or be treated conservatively. Then the steep acetabular roof has to be osteotomized and levered down to a normal angle and coverage to avoid redislocation or residual dysplasia. Different procedures have been described in the course of time. Two osteotomies are chiseling in the anterior to posterior direction. Salters innominate osteotomy levers the whole acetabulum with the lower part of the pelvis in an anterolateral direction around an axis passing through the pubic symphysis and the posterior part of the osteotomy. In Pembertons osteotomy the hinge for turning down the acetabular roof is the last, posterior, transverse cortical segment over the tri-radiate cartilage, short before the sciatic notch. Osteotomies chiseling from lateral in medial direction have been described already by Albee (1915) and Jones (1920). Lance (1925) propagated this technique in Europe. Here the acetabular roof is partially osteotomized in a thickness of 5–7 mm. Only the lateral part of the acetabulum is brought into the horizontal position. Wiberg in 1939 used this technique, but in 1953 he was the first to publish a full osteotomy what Dega called 1973 a transiliac osteotomy. Dega had originally learned the technique of Lance, but in 1963 when he reduced high dislocations after the technique of Colonna, he performed also a full transiliac osteotomy. After the Symposium of Chapchal in Basel 1965 we started in Berlin also with the complete acetabular osteotomy. With the control of an image intensifier the blade of the osteotome is driven toward the posterior rim of the tri-radiate cartilage leaving only a small bony rim above. Anteriorly the blade passes through the ant. inf. iliac spine. Posteriorly it just enters the sciatic notch. Here we check the blade position by direct palpation. The acetabulum is bent down partly in the small rim of bone left and mainly in the triradiate cartilage. Angles up to 50° have been achieved, which you cannot reach by other techniques. In the beginning we have combined after Mittelmeier and Witt this acetabuloplasty with a varus osteotomy of the femur. In our long-time follow-up (Brüning et al. 1988,1990) however, we found in almost 50% a subcapital coxa valga or a so-called head-in-neck-position of the femoral head. Then we avoided varusosteotomies and had good results without it (Pothmann). To keep the acetabular roof in the new position we used first bone wedges from the varus osteotomy, then deproteinized bone wedges from animals, and today deep frozen wedges of human femoral heads of the bone bank, sterilized at 121 degrees C for 20 min. (Ekkernkamp, Katthagen). A firm layer of cortical bone laterally is necessary. Reinvestigations have proven the stability of this material too ( Pothmann). This type of acetabular osteotomy in our and other authors opinion is the best. Salters osteotomy is not as efficient in severe dysplasia. And in older children it produces a decrease in anteversion of the acetabulum, which may limit internal rotation of the hip and cause osteoarthritis if it does not improve. In Pembertons osteotomy one cannot use the image intensifier, which is of great help to perform the osteotomy exactly and also the levering of the acetabulum to the optimal coverage. Our first long-time follow-up of children with additional varus-osteotomies (Brüning et al.) reviewed 90 hip joints in 67 children. The age at operation was in average 3.6 years, the age at follow-up 15 years. Clinical results. 98% of the patients had no pain or only occasional, no limitation of movement and normal or almost normal gait. The Trendelenburg sign was negative in 71% of the cases, grade 1 in 15.5% and grade 3 in 13.5%. Radiological evaluation. The mean value of the AC-angle (acetabular index) preoperatively was 33.8°, postoperatively normal with 16.3°. The acetabular angle of the weightbearing zone was at follow-up 9.7°, which is normal too. At the age of less than 18 years the CE angle of 25,9° was normal too, as well the instability (protrusion) index of Reimers of 12.3 % and the distance femoral head to teardrop figure with 8.8 mm. In our study group of hip dysplasia we introduced a score of normal values of hip measurements and 3 grades of deviation from normal, slightly pathological, severely pathological and extremely. When we counted normal values and slightly pathological ones together as a good result, we found for the different measurements of the acetabulum percentages mainly between 82 and 93 %. Remarkable were two measurements of the femoral neck, the epiphyseal index with only 50 % of normal and slightly pathological angles and the head-neck index with 47.7% respectively. This was due to the head-in-neck position of the femoral neck after varus osteotomy as we have mentioned already. Acetabular coverage is achieved best in transiliac osteotomies up to 10 years. Then, only by triple pelvic osteotomies the acetabulum in total can be redirected to a normal coverage. But this operation is more difficult. Residual dysplasias therefore should be treated as early as possible in the way demonstrated here

Objectives. There remains a lack of data on the reliability of methods to estimate tibial coverage achieved during total knee replacement. In order to address this gap, the intra- and interobserver reliability of a three-dimensional (3D) digital templating method was assessed with one symmetric and one asymmetric prosthesis design. Methods. A total of 120 template procedures were performed according to specific rotational and over-hang criteria by three observers at time zero and again two weeks later. Total and sub-region coverage were calculated and the reliability of the templating and measurement method was evaluated. Results. Excellent intra- and interobserver reliability was observed for total coverage, when minimal component overhang (intraclass correlation coefficient (ICC) = 0.87) or no component overhang (ICC = 0.92) was permitted, regardless of rotational restrictions. Conclusions. Measurement of tibial coverage can be reliable using the templating method described even if the rotational axis selected still has a minor influence

Introduction:. Tibial component fit, specifically significant overhang of tibial plateau or underhang of cortical bone, can lead to pain, loosening and subsidence. The purpose was to utilize morphometric data to compare size, match, and fit between patient specific and incrementally sized standard unicompartmental knee arthroplasty (UKA) implants. Methods:. CT images of 20 medial UKA knees and 10 lateral UKA knees were retrospectively reviewed. Standard and patient-specific implants were modeled in CAD, utilizing sizing templates and patient-specific CAD Designs. Virtual surgery maximized coverage of tibial plateau while minimizing implant overhang. Tibial plateau implant coverage was evaluated for fit and incidence of overhang/undercoverage. RESULTS:. Patient specific implants provided significantly greater cortical rim coverage versus incrementally sized standard implants, 77% v. 43% (range 41–46%) respectively medially (p < 0.0001) and 60% v. 37% (range 29–41%) laterally (p < 0.0001). Patient-specific and standard implants' arc length were evaluated for percent of implant edge on cortical bone, 84% v. 55% (range 48–59%) medially (p < 0.0001) and 79% v. 57% (range 53–60%) laterally (p < 0.0001). Average amount of overhang/undercoverage of cortical rim area differed in patient-specific and standard implants: 0.24 mm v. 0.46 mm maximum overhang, (p = 0.043); 0.87 mm vs. 3.01 mm maximum undercoverage medially (p < 0.0001); 0.14 mm vs. 0.59 mm maximum overhang, (p = 0.05); 1.19 mm vs. 2.26 mm maximum undercoverage laterally (p = 0.017). Anterior overhang yielded 25 −75% and 30–80% of medial and lateral implants respectively in standard implant group; no overhang in patient-specific implant group. Conclusions:. Tibial plateau anatomy variability produces difficulty optimizing coverage and preventing significant implant overhang/undercoverage with standard unicompartmental implants. Using virtual implantation, standard implants were undersized to avoid overhang. However, we encountered significantly more overhang in standard implants versus patient specific cohort. This study removed variability matching tibial tray and femoral standard group implant placement. Patient-specific implants provide superior cortical bone coverage and fit while minimizing issues of overhang and undercoverage seen in standard implants