Internal Rotation Group Research Articles

Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery

Background: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. Purpose: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. Study Design: Case series; Level of evidence, 4. Methods: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. Results: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, –2.4°± 2.2° and −3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (β = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). Conclusion: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Long-term effect of immobilization in external rotation after first-time shoulder dislocation: an average 18-year follow-up.

Immobilization in external rotation (ER) after a first-time shoulder dislocation was introduced to reduce the risk of recurrence compared with immobilization in internal rotation (IR), but its efficacy remains controversial. The purpose of this study was to determine the long-term effect of immobilization in ER after a first-time shoulder dislocation. Between October 2000 and March 2004, 198 patients with a first-time anterior dislocation of the shoulder (average age 37) were randomly assigned to immobilization in ER (ER group = 104 shoulders) or IR (IR group = 94 shoulders) for 3 weeks. At an average 2-year follow-up, 159 patients (80.3%) were available for evaluation. In the current study, these 159 patients were further followed up and interviewed by telephone. The following items were evaluated: recurrent instability, apprehensive feeling, surgical intervention, limitation in the range of motion, return to sports, and the Single Assessment Numeric Evaluation (SANE) score. The average follow-up period was 18.2 years (range, 16-20 years). Fifty-six patients were available for follow-up with the follow-up rate of 35%. The number of recurrent patients was 6 of 27 (22%) in the ER group and 6 of 29 (21%) in the IR group (P = .889). The number of surgically stabilized patients was 3 of 27 (11%) in the ER group and 10 of 29 (34%) in the IR group (P = .038). In total, the recurrence rate was 33% (9 of 27) in the ER group and 55% (16 of 29) in the IR group (P = .100). Adding the surgical cases and those with the SANE score ≤70% as failure cases, the failure rate in the ER group (26%) was significantly lower than that in the IR group (52%) (P = .048). Among those who survived without surgical intervention, there were no significant differences in apprehensive feeling, return to sports, limited range of motion, and the SANE score between the groups. Immobilization in ER reduced the risk of surgical intervention compared with IR in the long term.

Immobilization in External Rotation Reduces the Risk of Recurrence After Primary Anterior Shoulder Dislocation: A Meta-analysis.

Background:The best method for nonsurgical treatment after primary dislocation of the shoulder is not clear. The efficacy of immobilization with the arm in external rotation (ER) compared with internal rotation (IR) remains controversial.Purpose:To determine the efficacy of ER immobilization versus IR immobilization on recurrence rate after primary dislocation of the shoulder from the evidence of randomized controlled trials.Study Design:Systematic review; Level of evidence, 2.Methods:Electronic databases (MEDLINE [Ovid SP], PubMed, Web of Science, EBM reviews, and CINAHL) and available proceedings according to the abstracts of major international meetings related to or including shoulder injuries and trauma were used to search for randomized controlled trials. Two independent investigators determined eligibility and carried out data extraction from the selected studies.Results:A total of 9 studies (817 patients) were selected for this meta-analysis. They included 668 male and 149 female patients, with a mean age ranging from 20.3 to 37.5 years. In the 9 pooled studies, the recurrence rate of shoulder dislocation was 21.5% (84/390) in the ER group versus 34.9% (130/373) in the IR group. ER immobilization significantly reduced the recurrence rate compared with IR immobilization (risk ratio, 0.56; P = .007). In the subgroup analysis of those immobilized full-time, ER immobilization was significantly more effective than IR immobilization in reducing the recurrence rate (risk ratio, 0.57; P = .01). In the subgroup analysis of age, ER immobilization was significantly more effective than IR immobilization in those aged 20 to 40 years but not in those younger than 20 years.Conclusion:This meta-analysis demonstrates that ER immobilization reduces the recurrence rate after primary shoulder dislocation compared with IR immobilization in patients older than 20 years. When treating a patient with primary shoulder dislocation, the clinician should provide this information to the patient before a treatment method is selected.

Conservative management following closed reduction of traumatic anterior dislocation of the shoulder.

Conservative management following closed reduction of traumatic anterior dislocation of the shoulder.

Immediate effects of leg-press exercises with tibial internal rotation on individuals with medial knee osteoarthritis.

Although patients with knee osteoarthritis (OA) demonstrate abnormal kinematics involving greater tibial external rotation during squatting, there have not been any previous studies investigating an exercise focused on correcting knee rotational kinematics. This study aimed to determine the immediate effects of exercise with tibial internal rotation (IR) on symptoms and functions in patients with knee osteoarthritis (KOA). This study provides Level II evidence using a small randomized controlled trial. Sixty patients were allocated to either the tibial IR or neutral rotation (NR) group in this randomized controlled trial. The IR group performed a leg press activity with the tibia in maximal IR, whereas the NR group performed leg press activity with the tibia in NR. Outcome measures were (a) 10-m walk test; (b) Timed Up and Go test, (c) knee flexion angle while squatting, (d) knee pain during walking and squatting, and (e) difficulty during walking and squatting. Significant interaction was observed in all outcomes. The IR group exhibited significant improvement on all outcome measures, whereas the NR group exhibited significant improvements only in the 10-m walk. The IR group exhibited greater improvements than the NR group on all outcome measures. After a single session, leg press activity with the tibia in maximal IR improved the symptoms and functions measured in this study more effectively than leg press activity with the tibia in a neutral position. This suggests that correcting rotational malalignment is more important than strengthening the quadriceps for maintaining or even improving function of OA knees. (Clinical trials registration number: UMIN000021751).

Immobilization in External Rotation Versus Internal Rotation After Primary Anterior Shoulder Dislocation

Background: The recurrence rate after primary anterior shoulder dislocation is high, especially in young, active individuals. Recent studies have suggested external rotation immobilization as a method to reduce the rate of recurrent shoulder dislocation in comparison to traditional sling immobilization. Purpose: To assess and summarize evidence from randomized controlled trials on the effect of internal rotation versus external rotation immobilization on the rate of recurrence after primary anterior shoulder dislocation. Study Design: Meta-analysis. Methods: PubMed, MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and abstracts from recent proceedings were searched for eligible studies. Two reviewers selected studies for inclusion, assessed methodological quality, and extracted data. Results: Six randomized controlled trials (632 patients) were included in this review. Demographic and prognostic variables measured at baseline were similar in the pooled groups. The average age was 30.1 years in the pooled external rotation group and 30.3 years in the pooled internal rotation group. Two studies found that external rotation immobilization reduced the rate of recurrence after initial anterior shoulder dislocation compared with conventional internal rotation immobilization, whereas 4 studies failed to find a significant difference between the 2 groups. This meta-analysis suggested no overall significant difference in the rate of recurrence among patients treated with internal rotation versus external rotation immobilization (risk ratio, 0.69; 95% CI, 0.42-1.14; P = .15). There was no significant difference in the rate of compliance between internal and external rotation immobilization (P = .43). The Western Ontario Shoulder Instability Index scores were pooled across 3 studies, and there was no significant difference between the 2 groups (P = .54). Conclusion: Immobilization in external rotation is not significantly more effective in reducing the recurrence rate after primary anterior shoulder dislocation than immobilization in internal rotation. Additionally, this review suggests that there is minimal difference in patients’ perceptions of their health-related quality of life after immobilization in internal versus external rotation.

Comments on “Low-Cost Alternative External Rotation Shoulder Brace and Review of Treatment in Acute Shoulder Dislocations”

Lacy K, Cooke C, Cooke P, et al. Low-cost alternative external rotation shoulder brace and review of treatment in acute shoulder dislocations. West J Emerg Med. 2015;16(1):114–120. To the Editor: We read the paper of Lacy et al. (2015) with interest.1 The authors present a narrative review of the use of external rotation bracing in acute shoulder dislocations. One of the weaknesses of a narrative review is that it is more likely to be subject to reporting bias. In their review the authors focus on published studies that demonstrated successful outcomes. The first two originate from Itoi et al. whose 2003 randomized controlled trial popularized the concept of external rotation bracing in this patient group.2,3 However, their good results have not been replicated in three subsequent randomized controlled trials.4–6 The third study cited concluded that external rotation bracing was advantageous.7 However, the major confounding factor in that study was that the internal rotation group had a younger mean age. As this is a well-established risk factor for re-dislocation the results of this study should be interpreted with caution.8,9 Furthermore, a recent systematic review and meta-analysis also concluded that ER bracing is not advantageous.10,11 We feel that the narrative review in this publication does not provide a balanced overview of the clinical studies available and we question the value of external rotation in the management of these patients. Lacy et al. also describe the production of a low-cost external rotation brace that is more cost effective than those commercially available. The image of the sling provided demonstrates that this device produces only a small degree of external rotation. A recent systematic review demonstrated that reduction of the labrum is only achieved in 35% of cases when the arm is positioned in over 30 degrees of external rotation.12 However, the clinical studies previously discussed3–5,7 only achieved 10 to 20 degrees of rotation, and the illustration of the described technique in this paper suggests even less was achieved with this alternative brace. As a result, its effectiveness in achieving labral reduction and shoulder stability cannot be extrapolated from previous studies where a higher degree of rotation was obtained. An additional factor not addressed is the acceptability of the splint to patients. External rotation bracing is extremely inconvenient and poorly tolerated. Its prescription is associated with poor compliance, which may limit effectiveness.3–5 In closing we commend the authors on their innovative thinking and consider their design to be a cost-effective alternative to commercially available external rotation braces for posterior dislocations. However, the lack of any clear advantage to external rotation bracing for anterior shoulder dislocations in previous systematic reviews and meta-analysis should limit the subjection of patients to this poorly tolerated brace. The cheaper, more readily available internal rotation sling remains the standard treatment for these patients.

Immobilization in External Rotation After Primary Shoulder Dislocation Did Not Reduce the Risk of Recurrence

The treatment of primary traumatic anterior shoulder dislocation varies widely from no immobilization, to two or three weeks of immobilization in internal rotation with the arm in a sling, to treatment with a brace in external rotation. The aim of the present clinical trial was to compare immobilization in internal and external rotation after anterior shoulder dislocation. One hundred and eighty-eight patients with a primary anterior traumatic dislocation of the shoulder were randomly assigned to treatment with immobilization in either internal rotation (ninety-five patients) or external rotation (ninety-three patients) for three weeks. The primary outcome measure was a recurrent dislocation within twenty-four months of follow-up. The follow-up rate after a minimum period of two years was 97.9% (ninety-three of ninety-five) in the internal rotation group and 97.8% (ninety-one of ninety-three) in the external rotation group. The compliance rate with the immobilization was 47.4% (forty-five of ninety-five) in the internal rotation group and 67.7% (sixty-three of ninety-three) in the external rotation group. The intention-to-treat analyses showed that the recurrence rate was 24.7% (twenty-three of ninety-three) in the internal rotation group and 30.8% (twenty-eight of ninety-one) in the external rotation group (p = 0.36). Immobilization in external rotation does not reduce the rate of recurrence for patients with first-time traumatic anterior shoulder dislocation.

Immobilization of the shoulder in external rotation for prevention of recurrence in acute anterior dislocation

We aimed to compare the functional and stability outcomes of the patients with acute anterior shoulder dislocation, who were stabilized at external versus internal rotation. A total of 33 patients (31 males and 2 females) with the diagnosis of acute primary traumatic anterior shoulder dislocation were immobilized at internal (n=17) or external rotation (n=16). The mean follow-up period was 20.85 months (range 6-41 months). Patients received rehabilitation program immediately after splinting. We assessed functionality by Constant-Murlay score and stability by Rowe scoring system in 6th month. Control examinations were performed in 12th and 24th months. There were no statistically significant differences between internal rotation and external rotation groups in terms of Constant-Murlay and Rowe scores. Recurrent dislocation rate was 6.3% (1/16) in external rotation group and 29.4% (5/17) in internal rotation group (p>0.05). In the subgroup of patients aged between 21-30 years, while no recurrent dislocation was seen in external rotation group, 5 patients developed recurrent dislocation in internal rotation group(p=0.035). Immobilization of the shoulder in external rotation is an effective technique for prevention of recurrent dislocations in acute anterior shoulder dislocation and should be preferred to traditional splinting in internal rotation in clinical practice.

Do Bankart lesions heal better in shoulders immobilized in external rotation?

Background and purpose Immobilization in external rotation (ER) for shoulder dislocation has been reported to improve the coaptation of Bankart lesions to the glenoid. We compared the position of the labrum in patients treated with immobilization in ER or internal rotation (IR). A secondary aim was to evaluate the rate of Bankart lesions.Patients and methods 55 patients with primary anterior shoulder dislocation, aged between 16 and 40 years, were randomized to immobilization in ER or IR. Computer tomography (CT) and magnetic resonance imaging (MRI) were performed shortly after the injury. After the immobilization, MRI arthrography was performed. We evaluated the rate of Bankart lesions and measured the separation and displacement of the labrum as well as the length of the detached part of the capsule on the glenoid neck.Results Immobilization in ER reduced the number of Bankart lesions (OR = 3.8, 95% CI: 1.1 –13; p = 0.04). Separation decreased to a larger extent in the ER group than in the IR group (mean difference 0.6 mm, 95% CI: 0.1 – 1.1, p = 0.03). Displacement of the labrum and the detached part of the capsule showed no significant differences between the groups.Interpretation Immobilization in ER results in improved coaptation of the labrum after primary traumatic shoulder dislocation.

Bracing in external rotation for traumatic anterior dislocation of the shoulder

We undertook a prospective study in 51 male patients aged between 17 and 27 years to ascertain whether immobilisation after primary traumatic anterior dislocation of the shoulder in external rotation was more effective than immobilisation in internal rotation in preventing recurrent dislocation in a physically active population. Of the 51 patients, 24 were randomised to be treated by a traditional brace in internal rotation and 27 were immobilised in external rotation of 15 degrees to 20 degrees. After immobilisation, the patients undertook a standard regime of physiotherapy and were then assessed clinically for evidence of instability. When reviewed at a mean of 33.4 months (24 to 48) ten from the external rotation group (37%) and ten from the internal rotation group (41.7%) had sustained a further dislocation. There was no statistically significant difference (p = 0.74) between the groups. Our findings show that external rotation bracing may not be as effective as previously reported in preventing recurrent anterior dislocation of the shoulder.

Immobilization in External Rotation After Shoulder Dislocation Reduces the Risk of Recurrence

An initial anterior dislocation of the shoulder becomes recurrent in 66% to 94% of young patients after immobilization of the shoulder in internal rotation. Magnetic resonance imaging and studies of cadavera have shown that coaptation of the Bankart lesion is better with the arm in external rotation than it is with the arm in internal rotation. Our aim was to determine the benefit of immobilization in external rotation in a randomized controlled trial. One hundred and ninety-eight patients with an initial anterior dislocation of the shoulder were randomly assigned to be treated with immobilization in either internal rotation (ninety-four shoulders) or external rotation (104 shoulders) for three weeks. The primary outcome measure was a recurrent dislocation or subluxation. The minimum follow-up period was two years. The follow-up rate was seventy-four (79%) of ninety-four in the internal rotation group and eighty-five (82%) of 104 in the external rotation group. The compliance rate was thirty-nine (53%) of seventy-four in the internal rotation group and sixty-one (72%) of eighty-five in the external rotation group (p = 0.013). The intention-to-treat analysis revealed that the recurrence rate in the external rotation group (twenty-two of eighty-five; 26%) was significantly lower than that in the internal rotation group (thirty-one of seventy-four; 42%) (p = 0.033) with a relative risk reduction of 38.2%. In the subgroup of patients who were thirty years of age or younger, the relative risk reduction was 46.1%. Immobilization in external rotation after an initial shoulder dislocation reduces the risk of recurrence compared with that associated with the conventional method of immobilization in internal rotation. This treatment method appears to be particularly beneficial for patients who are thirty years of age or younger.

投球動作解析システムによるＴＯＰポジションの運動学的解析

Baseball pitching involves a complicated and rapid movement that has been investigated to prevent injuries and to improve the pitching performance. It is difficult to assess the pitching motion with high accuracy and a high sampling rate, due to the limitations of preexistent camera systems. The current camera system, however, has enough capacity to measure pitching motions with high accuracy and a high sampling rate.We have been diagnosing shoulder joint injuries caused by pitching. The patients (N = 939) felt pain during the pitching sequence as follows: top position (32.5%), maximum external rotation (27.2%), and ball release (14.5%). Hence the top position is one of the most important postures to investigate the mechanisms of shoulder joint injury in pitchers. There have been no studies that focused on the top position, however.The main purpose of this study was to develop a system to assess the pitching motion accurately. Another purpose was to estimate the instant of the top position and evaluate the kinematics of the shoulder and elbow joints.Pitching movement was assessed using a motion capture system (ProReflex MCU500, Qualisys Inc., Sweden) in a studio that has an official pitcher’s mound and home base. This system can record the positions of reflective markers at 500 Hz using seven CCD cameras. Thirty-two markers were mounted on the joints and body landmarks of each subject. Two markers were mounted on the ball. The pitching motions of eleven subjects were assessed, after a period for warm up. Kinematics parameters were calculated using three-axis gyroscopic Euler angle.The instant of the top position was observed for all subjects before the lead foot touched the ground. The interval from the top position to ball release was 0.242 ± 0.0438 [s] (n = 11). The subjects were divided into two groups by the type of posture at the instant of the top position, as follows: internal rotation group (n = 5), 11.8 ± 6.08 degrees, and external rotation group (n = 6), 38.1 ± 19.97. Other kinematics parameters at the top position were adduction of the shoulder at 74.2 ± 19.84 degrees, horizontal adduction of the shoulder at 37.3 ± 14.10 degrees, and extension of the elbow at 92.1 ± 21.63 degrees. The timing and posture of the estimated top position were almost the same as those of the conventional top position.From the top position to lead foot contact on the pitching sequence, there were three patterns of elbow leading. The three patterns did not depend upon experience. We interpreted them as individual variations.

The far infrared spectrum of nitroethane

The far infrared spectrum of nitroethane measured by Founer spectroscopy in the 8-60 cm −1 is presented and interpreted in terms of a rigid frame-rigid top model for free internal rotation group. Ratational-internal rotational energy levels and absolute absorption intensities are calculated to first order for an optimal choice of molecule-fixed axes. The computed absorption based on a permanent dipole moment of 3.4 debye along the NC direction is in excellent agreement with the observed band.