BACKGROUND:Transfer of the latissimus dorsi tendon to the greater tuberosity of the humerus for treatment of an irreparable rotator cuff tear has been reported to yield good-to-excellent short to ...intermediate-term results in well-selected patients. The purpose of this study was to evaluate the long-term outcome of such transfers for irreparable posterosuperior rotator cuff tears to determine the durability of the results and to identify risk factors for an unfavorable outcome.
METHODS:Fifty-seven shoulders in fifty-five patients (seventeen women and thirty-eight men with a mean age of fifty-six years) were managed with latissimus dorsi tendon transfer. Final follow-up was performed at a mean of 147 months. Outcome measures included the Constant score and the Subjective Shoulder Value (SSV). Osteoarthritis, the acromiohumeral distance, and the so-called critical shoulder angle were assessed on standardized radiographs.
RESULTS:Forty-six shoulders in forty-four patients were available at the time of final follow-up. The mean SSV increased from 29% preoperatively to 70% at the time of final follow-up, the relative Constant score improved from 56% to 80%, and the pain score improved from 7 to 13 points (p < 0.0001 for all). Mean flexion increased from 118° to 132°, abduction increased from 112° to 123°, and external rotation increased from 18° to 33°. Mean abduction strength increased from 1.2 to 2.0 kg (p = 0.001). There was a slight but significant increase in osteoarthritic changes. Inferior results occurred in shoulders with insufficiency of the subscapularis muscle and fatty infiltration of the teres minor muscle. Superior functional results were observed in shoulders with a small postoperative critical shoulder angle.
CONCLUSIONS:Latissimus dorsi tendon transfer offered an effective treatment for irreparable posterosuperior rotator cuff tears, with substantial and durable improvements in shoulder function and pain relief. Shoulders with fatty infiltration of the teres minor muscle and insufficiency of the subscapularis muscle tended to have inferior results, as did those with a large critical shoulder angle.
LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Purpose To investigate the usefulness and conduct validation of a simulated arthroscopy training device to train basic arthroscopy skills. Methods Forty-six participants including 12 novices, 12 ...intermediates, and 22 experts completed a questionnaire regarding demographics, previous arthroscopic experience, training potential, and statements about the device. Furthermore, participants performed a single task on the arthroscopic training device using the 0° camera and a probe. The task consisted of an attempt to carry a rubber ring across a helix inside a box as fast as possible. Construct validity was evaluated by comparing total task time and portal replacements of the camera and probe between all groups (median values interquartile range; Kruskal-Wallis test). Results The median age was 35 (29-44) years. There were 4 female and 42 male participants. A total of 89% of the participants graded the overall training capacity ≥5 (35% graded it as 5, 39% as 6, and 15% as 7), and 83% believed that it is useful to improve any kind of arthroscopy. Ninety-three percent of the participants would recommend the arthroscopic training device to their colleagues. Sixty-one percent of the participants stated that there are certain disadvantages. The median time to complete the task was 108 (58-236) seconds. Novices (259 123-435 seconds) performed tasks significantly slower than intermediates (169 67-257 seconds) and experts (75 49-132 seconds) ( P = .005). Furthermore, portal changes were significantly more common in novices and intermediates than experts ( P = .019). Conclusions High scores in training potential were achieved with this arthroscopy simulator box, and most study participants believed that practice with the arthroscopic training device is useful for any kind of arthroscopy. Construct validity was established since novices, intermediates, and experts in real arthroscopy were discriminated with the arthroscopic training device in terms of time to successful completion of a task. However, 61% of the participants stated that there were certain disadvantages. Clinical Relevance In every training tool using simulation, it is crucial to pass the first steps in the validation cascade. This study provides this step for further evaluation of this arthroscopic training device.
Most studies demonstrated, that training on a virtual reality based arthroscopy simulator leads to an improvement of technical skills in orthopaedic surgery. However, how long and what kind of ...training is optimal for young residents is unknown. In this study we tested the efficacy of a standardized, competency based training protocol on a validated virtual reality based knee- and shoulder arthroscopy simulator.
Twenty residents and five experts in arthroscopy were included. All participants performed a test including knee -and shoulder arthroscopy tasks on a virtual reality knee- and shoulder arthroscopy simulator. The residents had to complete a competency based training program. Thereafter, the previously completed test was retaken. We evaluated the metric data of the simulator using a z-score and the Arthroscopic Surgery Skill Evaluation Tool (ASSET) to assess training effects in residents and performance levels in experts.
The residents significantly improved from pre- to post training in the overall z-score: - 9.82 (range, - 20.35 to - 1.64) to - 2.61 (range, - 6.25 to 1.5); p < 0.001. The overall ASSET score improved from 55 (27 to 84) percent to 75 (48 to 92) percent; p < 0.001. The experts, however, achieved a significantly higher z-score in the shoulder tasks (p < 0.001 and a statistically insignificantly higher z-score in the knee tasks with a p = 0.921. The experts mean overall ASSET score (knee and shoulder) was significantly higher in the therapeutic tasks (p < 0.001) compared to the residents post training result.
The use of a competency based simulator training with this specific device for 3-5 h is an effective tool to advance basic arthroscopic skills of resident in training from 0 to 5 years based on simulator measures and simulator based ASSET testing. Therefore, we conclude that this sort of training method appears useful to learn the handling of the camera, basic anatomy and the triangulation with instruments.
Subtrochanteric or supracondylar femoral rotational osteotomies are established surgical treatments for femoral rotational deformities. Unintended change of the mechanical leg axis is an identified ...problem. Different attempts exist to plan a correct osteotomy plane, but implementation of the preoperative planning into the surgical situation can be challenging. Goal of this study was to identify the critical threshold of mal-angulation of the osteotomy plane and of femoral rotation that leads to a relevant deviation of the postoperative mechanical leg axis using a computer simulation approach.
Three-dimensional (3D) surface models of the lower extremity of two patients (Model 1: 42° femoral antetorsion; Model 2: 6° femoral retrotorsion) were generated from computed tomography data. First, baseline subtrochanteric and supracondylar rotational osteotomies, perpendicular to the femoral mechanical axis were simulated. Afterwards, mal-angulated osteotomies in sagittal and frontal plane followed by different degrees of rotation were simulated and frontal mechanical axis was analyzed.
400 mal-angulated osteotomies have been simulated. Mal-angulation of ±30° with 30° rotation showed maximum deviation from preoperative mechanical axis in subtrochanteric osteotomies (4.0° ± 0.4°) and in supracondylar osteotomies (12.4° ± 0.8°). Minimal mal-angulation of 15° in sagittal plane in subtrochanteric osteotomies and mal-angulation of 10° in sagittal plane in supracondylar osteotomies altered the mechanical axis by > 2°. Mal-angulation in sagittal plane showed higher deviations of the mechanical axis (up to 12.4° ± 0.8°), than in frontal plane mal-angulation (up to 4.0° ± 1.9°).
A femoral rotational osteotomy, perpendicular to the femoral mechanical axis, has no considerable influence on the mechanical leg axis. However, mal-angulation of femoral rotational osteotomies showed relevant changes of the mechanical leg axis. In supracondylar respectively subtrochanteric procedures, mal-angulation of only 10° in combination with already 15° of femoral rotation respectively mal-angulation of 15° in combination with 30° of femoral rotation, can lead to a relevant postoperative mechanical leg axis deviation of more than 2°, wherefore these patients probably would benefit from the use of navigation aids.
Abstract
Background
The Ganz’ periacetabular osteotomy (PAO) consists of four technically challenging osteotomies (OT), namely, supraacetabular (saOT), pubic (pOT), ischial (iOT), and retroacetabular ...OT (raOT).
Purpose
We performed a proof of concept study to test (1) the feasibility of augmented reality (AR) guidance for PAO, (2) precision of the OTs guided by AR compared to the freehand technique performed by an experienced PAO surgeon, and (3) the effect of AR on performance depending on experience.
Methods
A 3D preoperative plan of a PAO was created from segmented computed tomography (CT) data of an anatomic plastic pelvis model (PPM). The plan was then embedded in a software application for an AR head-mounted device. Soft tissue coverage was imitated using foam rubber. The 3D plan was then registered onto the PPM using an anatomical landmark registration. Two surgeons (one experienced and one novice PAO surgeon) each performed 15 freehand (FH) and 15 AR-guided PAOs. The starting point distances and angulation between the planned and executed OT planes for the FH and the AR-guided PAOs were compared in post-intervention CTs.
Results
AR guidance did not affect the performance of the expert surgeon in terms of the mean differences between the planned and executed starting points, but the raOT angle was more accurate as compared to FH PAO (
p
= 0.0027). AR guidance increased the accuracy of the performance of the novice surgeon for iOT (
p
= 0.03). An intraarticular osteotomy performed by the novice surgeon with the FH technique could be observed only once.
Conclusion
AR guidance of osteotomies for PAOs is feasible and seems to increase accuracy. The effect is more accentuated for less-experienced surgeons.
Clinical relevance
This is the first proof of concept study documenting the feasibility of AR guidance for PAO. Based on these findings, further studies are essential for elaborating on the potential merits of AR guidance to increase the accuracy of complex surgical procedures.
Purpose To investigate the association between arthroscopy simulator performance and video game skills. Methods This study compared the performances of 30 volunteers without experience performing ...arthroscopies in 3 different tasks of a validated virtual reality knee arthroscopy simulator with the video game experience using a questionnaire and actual performances in 5 different 2- and 3-dimensional (D) video games of varying genres on 2 different platforms. Results Positive correlations between knee arthroscopy simulator and video game performances (ρ = 0.63, P < .001) as well as experiences (ρ = 0.50, P = .005) were found. The strongest correlations were found for the task of catching (hooking) 6 foreign bodies (virtual rings; “triangulation”) and the dribbling performance in a sports game and a first-person shooter game, as well as the meniscus resection and a tile-matching puzzle game (all ρ ≥ 0.60, P < .001). No correlations were found for any of the knee arthroscopy simulator tasks and a strategy game. Conclusions Although knee arthroscopy performances do not correlate with 2-D strategy video game skills, they show a correlation with 2-D tile-matching puzzle games only for easier tasks with a rather limited focus, and highly correlate with 3-D sports and first-person shooter video games. These findings show that experienced and good 3-D gamers are better arthroscopists than nonexperienced and poor 3-D gamers. Level of Evidence Level II, observational cross-sectional study.
There have been conflicting studies published regarding the ability of various total knee arthroplasty (TKA) techniques to correct preoperative deformity. The purpose of this study was to compare the ...postoperative radiographic alignment in patients with severe preoperative coronal deformity (≥10° varus/valgus) who underwent three different TKA techniques; manual instrumentation (MAN), computer navigated instrumentation (NAV) and patient specific instrumentation (PSI).
Patients, who received a TKA with a preoperative coronal deformity of ≥10° with available radiographs were included in this retrospective study. The groups were: MAN; n = 54, NAV; n = 52 and PSI; n = 53. The mechanical axis (varus / valgus) and the posterior tibial slope were measured and analysed using standing long leg- and lateral radiographs.
The overall mean postoperative varus / valgus deformity was 2.8° (range, 0 to 9.9; SD 2.3) and 2.5° (range, 0 to 14.7; SD 2.3), respectively. The overall outliers (>3°) represented 30.2% (48 /159) of cases and were distributed as followed: MAN group: 31.5%, NAV group: 34.6%, PSI group: 24.4%. No significant statistical differences were found between these groups. The distribution of the severe outliers (>5°) was 14.8% in the MAN group, 23% in the NAV group and 5.6% in the PSI group. The PSI group had significantly (p = 0.0108) fewer severe outliers compared to the NAV group while all other pairs were not statistically significant.
In severe varus / valgus deformity the three surgical techniques demonstrated similar postoperative radiographic alignment. However, in reducing severe outliers (> 5°) and in achieving the planned posterior tibial slope the PSI technique for TKA may be superior to computer navigation and the conventional technique. Further prospective studies are needed to determine which technique is the best regarding reducing outliers in patients with severe preoperative coronal deformity.
The skin commensal Cutibacterium avidum has been recognized as an emerging pathogen for periprosthetic joint infections (PJI). One currently assumes that the early occurring PJIs are a consequence of ...skin commensals contaminating the peri-implant tissue during surgery. We addressed whether standard skin antisepsis with povidone-iodine/alcohol before total hip arthroplasty (THA) is effective to eliminate colonizing bacteria with focus on C. avidum.
In a single-center, prospective study, we screened all patients for skin colonizing C. avidum in the groin before THA. Only in the patients positive for C. avidum, we preoperatively repeated skin swabs after the first and third skin antisepsis and antibiotic prophylaxis. We also obtained dermis biopsies for microbiology and fluorescence in situ hybridization (FISH).
Fifty-one out of 60 patients (85%) were colonized on the skin with various bacteria, in particular with C. avidum in 12 out of 60. Skin antisepsis eliminated C. avidum in eight of ten (20%) colonized patients undergoing THA. Deeper skin (dermis) biopsies were all culture negative, but FISH detected single positive ribosome-rich C. avidum in one case near sweat glands.
Standard skin antisepsis was not effective to completely eliminate colonizing C. avidum on the skin in the groin of patients undergoing THA. Colonizing with C. avidum might pose an increased risk for PJI when considering a THA. Novel more effective antisepsis strategies are needed. Trial registration No clinical trial.
Background It was the purpose of this paper to analyze structural, functional, and electrophysiologic variables that may determine preserved overhead function for patients with massive rotator cuff ...tears. Methods Nineteen patients (20 shoulders) were prospectively included in either the pseudoparalytic (n = 9) or the non-pseudoparalytic group (n = 11). Fatty infiltration was graded according to Goutallier, and anterior (subscapularis) and posterior (infraspinatus and teres minor) tear extension was graded 0 (no involvement) to 4 (full tear) on magnetic resonance imaging. Glenohumeral and scapulothoracic rhythm was assessed by fluoroscopic motion analysis, and electromyographic evaluation of the deltoid muscle was performed. Results We found no significant difference of fatty infiltration of the supraspinatus (3.9 vs 3.6), infraspinatus (3.9 vs 3.8), and teres minor (1.7 vs 0.6) or of the posterior tear extension (2.6 vs 2.0) between pseudoparalytic and non-pseudoparalytic shoulders. Global tear extension in the parasagittal plane (205° vs 163°) and subscapularis involvement (2.6 vs 1.2), however, showed significant differences between the two groups, and no patient with a full-thickness supraspinatus and infraspinatus tear with extension into the inferior half of the subscapularis was able to lift the arm to 90°. Fluoroscopic assessment revealed almost total loss of active glenohumeral abduction in the pseudoparalytic group. Conclusion Despite global tear extension, the single most important predictor for preserved shoulder function is the integrity of the inferior subscapularis insertion. Furthermore, electromyographic evaluation identifies a well-differentiated deltoid innervation as beneficial for a well-preserved shoulder function, but it does not protect from pseudoparalysis.
Augmented reality (AR)-based surgical navigation may offer new possibilities for safe and accurate surgical execution of complex osteotomies. In this study we investigated the feasibility of ...navigating the periacetabular osteotomy of Ganz (PAO), known as one of the most complex orthopedic interventions, on two cadaveric pelves under realistic operating room conditions. Preoperative planning was conducted on computed tomography (CT)-reconstructed 3D models using an in-house developed software, which allowed creating cutting plane objects for planning of the osteotomies and reorientation of the acetabular fragment. An AR application was developed comprising point-based registration, motion compensation and guidance for osteotomies as well as fragment reorientation. Navigation accuracy was evaluated on CT-reconstructed 3D models, resulting in an error of 10.8 mm for osteotomy starting points and 5.4° for osteotomy directions. The reorientation errors were 6.7°, 7.0° and 0.9° for the x-, y- and z-axis, respectively. Average postoperative error of LCE angle was 4.5°. Our study demonstrated that the AR-based execution of complex osteotomies is feasible. Fragment realignment navigation needs further improvement, although it is more accurate than the state of the art in PAO surgery.
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