Accuracy of cup placement compared with preoperative surgeon targets in primary total hip arthroplasty using standard instrumentation and techniques: a global, multicenter study.

BACKGROUND: Acetabular cup positioning in total hip arthroplasty (THA) is closely related to outcomes. The literature has suggested cup parameters defined by the Lewinnek safe zone; however, the validity of such measures is in question. Several studies have raised concerns about the benefits of using the Lewinnek safe zone as a predictor of success. In this study we elected to use prospective surgeon targets as the basis for comparison to see how successful surgeons are positioning their cup using standard instruments and techniques. METHODS: A prospective, global, multicenter study was conducted. Cup positioning success was defined as a composite endpoint. Both cup inclination and version needed to be within 10° of the surgeon target to be considered a success. Radiographic analysis was conducted by a third-party reviewer. RESULTS: In 170 subjects, inclination, target versus actual, was 44.8° [standard deviation (SD 0.9°)] and 43.1° (SD 7.6°), respectively (p = 0.0029). Inclination was considered successful in 84.1% of cases. Mean version, target versus actual, was 19.4° (SD 3.9°) and 27.2° (SD 5.6°), respectively (p < 0.0001). Version was considered successful in 63.4% of cases, and combined position (inclination and version) was considered successful in 53.1%. CONCLUSION: This study shows that with traditional methods of placing the cup intraoperatively, surgeons are only accurate 53.1% of the time compared with a predicted preoperative plan. This study suggests that the inconsistency in cup positioning based on the surgeon's planned target is potentially another important variable to consider while using a mechanical guide or in freehand techniques for cup placement in THA. TRIAL REGISTRATION: This study is registered on ClinicalTrials.gov, NCT03189303.

Cup orientation following posterior approach THA - the effect of different visual aids and pelvic supports.

INTRODUCTION: This study aims to compare cup inclination achieved (1) Using two orientation guides, whilst using the same 3-point pelvic positioner and (2) Using two types of pelvic positioners, whilst measuring intra-operative cup inclination with an inclinometer. MATERIALS AND METHODS: This is a prospective, diagnostic cohort study of a consecutive series of 150 THAs performed through a posterior approach. Two types of 3-point pelvic positioners were used (Stulberg and modified Capello Hip Positioners) and the cup was positioned freehand using one of two orientation guides (mechanical guide or digital inclinometer). Intra-operative inclination was recorded, radiographic cup inclination and anteversion were measured from radiographs. The differences in inclination due to pelvic position (ΔPelvicPosition) and orientation definitions (ΔDefinition) were calculated. Target radiographic inclination and anteversion was 40/20° ± 10°. RESULTS: There was no difference in radiographic cup inclination/ (p = 0.63) using a mechanical guide or digital inclinometer. However, differences were seen in ΔPelvicPosition between the positioners ((Stulberg: 0° ± 5 vs. Capello: 3° ± 6); p = 0.011). Intra-operative inclination at implantation was different between positioners and this led to equivalent cases within inclination/anteversion targets (Stulberg:84%, Capello:80%; p = 0.48). CONCLUSIONS: With the pelvis securely positioned with 3-point supports, optimum cup orientation can be achieved with both alignment guides and inclinometer. Non-optimal cup inclinations were seen when intra-operative inclinations were above 40° and below 32°, or the ΔPelvicPosition was excessive (> 15°; n = 2). We would thus recommend that the intra-operative cup inclination should be centered strictly between 30° and 35° relative to the floor. Small differences exist between different type of pelvic positioners that surgeons need to be aware off and account for.

Comparative Analysis Investigating the Impact of Implant Design on Hospital Length of Stay and Discharge Destination in a Dutch Hospital With an Established Enhanced Recovery Program.

BACKGROUND: Global demand for total knee arthroplasty (TKA) is increasing, driven by an aging and increasingly overweight patient population, culminating in higher healthcare costs. In the Netherlands, the number of TKA surgeries performed annually increased from 21,000 in 2010 to 29,000 in 2017. This study aimed to assess the impact of implant design on hospital length of stay (LOS), surgery time, and discharge destination (home vs a rehabilitation center) in a Dutch hospital with an established enhanced recovery program and short baseline LOS. METHODS: A retrospective review of consecutive adult patients who underwent primary TKA in a Dutch hospital between 2015 and 2017 using either the comparator device or the control device. RESULTS: A total of 200 patients were enrolled in the study (100 per group). Patients who received a comparator device had a significantly shorter LOS (adjusted mean 2.76 days; 95% confidence interval [CI]: 2.45, 3.11) vs the control group (adjusted mean 3.43 days; 95% CI: 3.08, 3.81; P < .01). The proportion of patients discharged to a rehabilitation center, instead of home, was also significantly lower in the comparator device group (adjusted 4.4%; 95% CI: 1.8, 10.7 vs adjusted 11.4%; 95% CI: 6.0, 20.6; P < .05). There was no difference in surgical time between the 2 groups. None of the sensitivity analyses performed affected the original analysis outcome. CONCLUSION: This study shows a modest but significant reduction in length of stay and lower rate of discharge to a rehabilitation center in the comparator device group.

Estimating Scaphoid Lengths Using Anatomical Measurements in the Wrist.

PURPOSE: In reconstructive surgery of scaphoid nonunions with humpback deformity, some surgeons recommend restoration of the normal scaphoid length whereas others overexpand the normal length to ensure carpal realignment and prevent late collapse. To be able to define overexpansion and investigate which levels of overexpansion yield optimal clinical results, a precise method for estimating the original scaphoid length is required. The purpose of this anatomic study was to investigate the precision of estimating normal scaphoid lengths based on intact adjacent bone dimensions, compared with using the contralateral scaphoid length. METHODS: From bilateral computed tomographic scans of 28 healthy wrist pairs, 3-dimensional virtual bone models were created. The left and right scaphoid lengths were determined at the central axis. The capitate length at the central axis and the distal radius width served to derive an ipsilateral scaphoid length estimate. Estimation precision for individual cases was based on the 95% range (±1.96 × SD) of the observed differences between the actual and estimated lengths. RESULTS: On average, the capitate length was 10% smaller than the scaphoid length; the radius width was 9% larger. Consequently, we averaged the capitate length and radius width for ipsilateral estimations. The average difference between the scaphoid length and the latter ipsilateral estimate was 0.1 mm. The average contralateral scaphoid length difference was also 0.1 mm. Estimation precisions, however, were ±2.2 and ±1.4 mm, respectively. CONCLUSIONS: Scaphoid length estimation based on the contralateral scaphoid is more precise than the estimating scaphoid length using the ipsilateral radius and capitate. CLINICAL RELEVANCE: Scaphoid overexpansion can be ensured if the restored length is at least 1.4 mm longer than the contralateral length. This may be valuable information when establishing a target length for reconstruction and investigating the consequences of scaphoid overexpansion on clinical function, such as range of motion, which are currently unknown.

Contemporary, non-navigation, cup orientation techniques improve accuracy and eliminate differences seen between the anterior and posterior approach in THA.

BACKGROUND: This study aimed to: (1) Determine the ability to achieve the surgeons' desired cup orientation, without navigation, using contemporary measures with the anterior- (AA) and posterior- approaches (PA); and (2) assess whether surgical approach is associated with cup orientation accuracy, as previously reported, when contemporary measures are used. METHODS: A prospective, 2-centre, multi-surgeon study of 400 THAs (200 AA; 200 PA) was performed. Intraoperative radiographs were obtained with the AA. A digital inclinometer and 3-point pelvic support were used with the PA. With the PA, intraoperative cup inclination at impaction was recorded. Radiographic inclination/anteversion (RI/RA) was measured from intraoperative radiographs (AA-only) and from postoperative radiographs for all cases. Optimum inclination/anteversion was defined as 40°/20° (±10°). The difference between intra- and postoperative orientations allowed for determination of the difference in pelvic position at impaction. RESULTS: Optimum RI and RA were achieved in 91.3% (n = 365) and 92% (n = 368) of cases respectively. Optimum cup orientation was detected in 84% of cases (n = 336). There was equivalent ability to achieve cup orientation between approaches (AA: 82.5% vs. PA: 85.5%; p = 0.41). The use of an inclinometer in the PA was associated with a smaller variability of inclination at implantation (10° vs. 14°) and counteracted the greater difference in pelvic position (4.4° vs. 2.1°) seen with the PA. CONCLUSIONS: Over 80% of cases can have optimum orientation without navigation, using simple, cheap contemporary measures. Such measures eliminate differences between approaches, related to patient position. Narrower implantation angles will further reduce variability in cup orientation achieved.

Spinopelvic challenges in primary total hip arthroplasty.

There is no universal safe zone for cup orientation. Patients with spinal arthrodesis or a degenerative lumbar spine are at increased risk of dislocation. The relative contributions of the hip (femur and acetabulum) and of the spine (lumbar spine) in body motion must be considered together. The pelvis links the two and influences both acetabular orientation (i.e. hip flexion/extension) and sagittal balance/lumbar lordosis (i.e. spine flexion/extension). Examination of the spino-pelvic motion can be done through clinical examination and standard radiographs or stereographic imaging. A single, lateral, standing spinopelvic radiograph would be able to providemost relevant information required for screening and pre-operative planning. A significant variability in static and dynamic spinopelvic characteristics exists amongst healthy volunteers without known spinal or hip pathology. The stiff, arthritic, hip leads to greater changes in pelvic tilt (changes are almost doubled), with associated obligatory change in lumbar lordosis to maintain upright posture (lumbar lordosis is reduced to counterbalance for the reduction in sacral slope). Following total hip arthroplasty and restoration of hip flexion, spinopelvic characteristics tend to change/normalize (to age-matched healthy volunteers). The static spinopelvic parameters that are directly associated with increased risk of dislocation are lumbo-pelvic mismatch (pelvic incidence - lumbar lordosis angle >10°), high pelvic tilt (>19°), and low sacral slope when standing. A high combined sagittal index (CSI) when standing (>245°) is associated with increased risk of anterior instability, whilst low CSI when standing (<205°) is associated with increased risk of posterior instability. Aiming to achieve an optimum CSI when standing within 205-245° (with narrower target for those with spinal disease) whilst ensuring the coronal targets of cup orientation targets are achieved (inclination/version of 40/20 ±10°) is our preferred method.

Influence of screw design, sex, and approach in scaphoid fracture fixation.

BACKGROUND: Screw fixation of scaphoid fractures has gained popularity. A long central screw has been shown to be biomechanically advantageous. QUESTIONS/PURPOSES: We compared the ability of different screw designs to obtain this goal and determined the influence of sex and approach on screw length. METHODS: We performed all measurements on three-dimensional reconstructions of 20 CT scans of normal scaphoids (10 men and 10 women) with the use of software. The three-dimensional computer models were analyzed, the central axis was defined, and the screws were placed along this axis. We compared 15 different available screw designs and volar and dorsal screw placement. RESULTS: The length of the scaphoid along its central axis was longer in men (mean, 27.14 mm; standard error of the mean, 0.97 mm) than in women (mean, 23.86 mm; standard error of the mean, 0.37 mm). The screw length that can be used was longer in the volar approach (mean, 23.72 mm; standard error of the mean, 0.19 mm) than in the dorsal approach (mean, 23.31 mm; standard error of the mean, 0.19 mm) regardless of the screw design. Screws with a trailing thread diameter greater than 3.9 mm and leading thread diameter greater than 3.0 mm were shorter. CONCLUSIONS: Scaphoids in women are smaller than in men. Theoretically, fixation of scaphoid fractures through a volar approach will allow the surgeon to use longer screws. The screw design has a significant influence on the screw length that can be used in scaphoid fracture fixation. We recommend using a differential pitch screw with a thread diameter of 3.9 mm or less.

Is the infection rate in primary THA increased after steroid injection?

BACKGROUND: Injection of the hip is performed for diagnostic and therapeutic reasons. Articular cartilage deterioration and increased risk of prosthetic infection have been reported with steroid injections. However, the literature contains contradictory reports on an increased risk of infection after a subsequent THA. QUESTIONS/PURPOSES: We asked whether intraarticular steroid injection increased the rate of infection of a subsequent THA. METHODS: We retrospectively reviewed records of 175 patients in whom intraarticular steroid injections were given under strictly aseptic conditions using a lateral approach within 1 year before THA. These patients were matched with others from our database who had not received an injection for comorbidities, and for American Society of Anesthesiologists score, age, BMI, sex, type of implant, and year of THA. RESULTS: We found no differences in the rate of deep or superficial infection between the two groups. One patient in the injected group and one in the control group had a late chronic infection. In three patients in the injected group and one in the control group, one of the intraoperative cultures was positive. Five patients in the injected group and seven in the control group had superficial infections develop. In seven patients in the injected group and five in the control group, there was prolonged wound drainage (> 5 days). None of these patients had a deep wound infection at latest followup. CONCLUSIONS: When used in strictly aseptic conditions, intraarticular steroid injection of the hip did not increase the risk of infection in patients subsequently undergoing THA. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Volar percutaneous transtrapezial fixation of scaphoid waist fractures: surgical technique.

Percutaneous screw fixation of scaphoid fractures has gained popularity over the years. The disadvantages of a long period of cast immobilisation are avoided and this technique allows a more rapid return to work and sports activities than conservative treatment. Consequently, percutaneous screw fixation is appealing for the young and active population. Biomechanical studies showed that greater fixation strength is obtained when the screw is placed centrally than eccentrically. Central screw placement can however be technically demanding. In the use of a volar percutaneous approach, the trapezium and the shape of the scaphoid impede central screw placement. Different approaches are available to overcome this difficulty. The volar percutaneous transtrapezial approach facilitates and allows more accurate central screw placement compared to approaches that try to avoid the trapezium. The surgical technique of this approach is described.

Thermal capsulorrhaphy in internal shoulder impingement: a 7-year follow-up study.

UNLABELLED: This study aimed to evaluate the long-term results of arthroscopic thermal shrinkage of the anterior capsule in athletes with internal shoulder impingement. In recent years, opinion with regards to the aetiology of internal shoulder impingement has changed significantly. The traditional treatment of internal impingement consisted of debridement of labral and/or undersurface cuff lesions. The use of concomitant thermal capsulorrhaphy, based on the concept of anteroinferior laxity, has also been advocated with excellent short-term results. In this study we investigated the long-term effects of this technique. Twelve overhead athletes with internal impingement underwent traditional arthroscopic treatment plus thermal capsulorrhaphy for internal impingement. All patients were evaluated 1, 2 and 7 years postoperatively using a questionnaire regarding their sports activity, and the modified Rowe score. At 1, 2 and 7 years postoperatively there was a significant improvement in the modified Rowe score when compared to the preoperative scores. However, follow-up at 7 years showed a significant deterioration of the initial 1 and 2 year results (p < 0.001), with only 25% of the athletes able to perform sports at their preoperative level. CONCLUSION: Excellent short-term results with thermal capsulorrhaphy, in addition to traditional arthroscopic treatment, in patients with internal shoulder impingement were not sustained over time. After 7 years, only 25% of the athletes were able to perform sports at their preoperative level.

Cup placement in primary total hip arthroplasty: how to get it right without navigation or robotics.

Acetabular component orientation and position are important factors in the short- and long-term outcomes of total hip arthroplasty. Different definitions of inclination and anteversion are used in the orthopaedic literature and surgeons should be aware of these differences and understand their relationships. There is no universal safe zone. Preoperative planning should be used to determine the optimum position and orientation of the cup and assess spinopelvic characteristics to adjust cup orientation accordingly. A peripheral reaming technique leads to a more accurate restoration of the centre of rotation with less variability compared with a standard reaming technique. Several intraoperative landmarks can be used to control the version of the cup, the most commonly used and studied is the transverse acetabular ligament. The use of an inclinometer reduces the variability associated with the use of freehand or mechanical alignment guides.

Preoperative radiographic assessment of limb-length discrepancy in total hip arthroplasty.

BACKGROUND: Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after THA but are subject to variation. Different methods are used to determine LLDs. As a pelvic reference, both ischial tuberosities and the teardrops are used, and as a femoral reference, the lesser trochanter and center of the femoral head are used. QUESTIONS/PURPOSES: We validated the different methods for preoperative radiographic measurement of LLDs and evaluated their reliability. PATIENTS AND METHODS: LLDs were measured on full-leg radiographs for 52 patients (29 men, 23 women) with osteoarthritis (OA) of the hip and compared with different methods for measuring LLDs on AP radiographs of the pelvis. RESULTS: The true LLD varied from -8.0 to 9.1 mm. When the biischial line was used as a pelvic reference, the LLD measured on AP pelvis radiographs was different from the true LLD. No difference was found when the interteardrop line was used as a pelvic reference. There was substantial interobserver agreement when the lesser trochanter was used as a femoral reference (kappa = 0.66-0.70) and excellent interobserver and intraobserver agreement for all other measurements (kappa = 0.84-0.93). CONCLUSIONS: Our data show use of the biischial line as a pelvic reference should be discouraged and the interteardrop line is a better alternative. The center of the femoral head is a more reliable femoral landmark compared with the lesser trochanter.

Long-term outcome after meniscal repair.

PURPOSE: the purpose of this study was to analyse the clinical and radiological results of meniscal repairs and identify factors that correlate with the success of this procedure. METHODS: a retrospective review of 119 meniscal repairs was completed. The average follow-up was 70 months. Successful meniscal repairs were observed critically in terms of radiographic changes and clinical outcomes and compared with failed meniscal repairs. RESULTS: the overall success rate of meniscal repairs was 74%. Meniscal repairs that were performed within 6 weeks of injury had better results (83%) than late repairs (52%). The best results were obtained with the inside-out technique using #0 PDS suture (80%) compared to all-inside Biofix arrows (70%) and combined repairs (63%). Patients with associated ACL injury had a better chance of a successful outcome, but this was only significant when the ACL was reconstructed at the time of repair (P < 0.05). Those patients who had failed meniscal repair had increased radiographic osteoarthritic changes (81%) on long-term follow-up compared to patients with successful repair (14%). CONCLUSION: this retrospective study shows the clinical and radiological importance of meniscal repair. Successful results in this study were associated with younger age and earlier repair using inside-out technique. Furthermore, increased success was seen in meniscal repairs performed in association with ACL reconstruction.

A comparison of 2 methods for scaphoid central screw placement from a volar approach.

PURPOSE: We studied 2 methods used for screw placement through a volar approach for fixation of scaphoid fractures. METHODS: We performed measurements on 20 computed tomography scans of unfractured scaphoids. A central virtual guidewire was computed in 10 scaphoids with the wrist in neutral or in extension and ulnar deviation. Second, we compared the central guidewire and a guidewire representing a volar approach to the scaphoid avoiding the trapezium. RESULTS: The central guidewire passed through the trapezium in all cases with the wrist either in neutral or in extension and ulnar deviation. There was a statistically significant difference only in the sagittal plane. When the central guidewire was compared with a guidewire placed through a standard volar approach, the latter was more eccentric in the distal and waist portions. CONCLUSIONS: We showed that central placement throughout the scaphoid with a standard volar approach is not feasible without partially resecting, manipulating, or drilling through the trapezium. CLINICAL RELEVANCE: Our data suggest that a volar transtrapezial approach can be an alternative for optimum central placement in volar percutaneous fixation of scaphoid fractures.

Incidence of scaphotrapezial arthritis following volar percutaneous fixation of nondisplaced scaphoid waist fractures using a transtrapezial approach.

PURPOSE: To investigate whether volar percutaneous screw fixation of scaphoid waist fractures via a transtrapezial approach causes degenerative changes at the scaphotrapezial (ST) joint at short- to medium-term follow-up. METHODS: A total of 34 patients were available for follow-up at a mean of 6.1 years (minimum follow-up, 3.7 y) after volar percutaneous fixation of acute scaphoid waist fractures via a transtrapezial approach. The clinical follow-up examination included assessment of pain using a visual analog scale, range of motion, grip strength, and key pinch strength. We obtained radiographs of both hands in 3 views. We staged degenerative changes at the ST joint according to the modified Eaton and Glickel classification. RESULTS: The modified Mayo wrist score showed excellent clinical results using the described technique. One patient showed asymptomatic unilateral stage 2 osteoarthritic changes at the ST joint. We noted 6 screw protrusions, which required screw removal in 2 patients, in the early stages of use of the transtrapezial technique. One patient was treated surgically for a bone cyst. CONCLUSIONS: Volar percutaneous screw fixation of nondisplaced scaphoid waist fractures using a transtrapezial approach does not lead to symptomatic scaphotrapezial osteoarthritis at short- to medium-term follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.