The subcoracoid distance is correlated with pain and internal rotation after reverse shoulder arthroplasty

Background

A proposed etiology of anterior shoulder pain and limited internal rotation after reverse shoulder arthroplasty (RSA) is impingement of the humeral component on the coracoid or conjoint tendon. The primary goal of this study was to investigate radiographic surrogates for potential coracoid or conjoint tendon impingement and their relationship to postoperative pain and internal rotation after RSA.

Methods

A retrospective review of a clinical registry was performed to identify patients with (1) primary RSA, (2) minimum 2-year clinical follow-up, and (3) satisfactory postoperative axillary lateral radiographs. The primary radiographic measurement of interest was the subcoracoid distance (SCD), defined as the distance between the posterior aspect of the coracoid and the anterior glenosphere. Additional measurements were as follows: anterior glenosphere overhang, posterior glenosphere overhang, native glenoid width, lateralization of glenosphere relative to the coracoid tip, lateralization shoulder angle, and distalization shoulder angle. The primary clinical outcome of interest was the 2-year postoperative Visual Analog Scale score. Secondary outcomes were (1) internal rotation (IR) defined by spinal level (IRspine), (2) IR at 90 degrees of abduction, (3) American Shoulder and Elbow Surgeons score, (4) forward flexion, and (5) external rotation at 0 degrees of abduction. Linear regression analyses were used to evaluate the relationship of the various radiographic measures on the clinical outcomes of interest.

Results

Two hundred seventeen patients were included. There was a statistically significant relationship between the SCD and Visual Analog Scale scores: B = -0.497, P = .047. There was a statistically significant relationship between the SCD and IRspine: B = -1.667, P < .001. Metallic lateralization was also positively associated with improving IRspine; increasing body mass index was negatively associated. There was a statistically significant relationship between the SCD and IR at 90 degrees of abduction: B = 5.844, P = .034.

Conclusion

For RSA with a 135° neck shaft angle and lateralized glenoid, the postoperative SCD has a significant association with pain and IR. Decreasing SCD was associated with increased pain and decreased IR, indicating that coracoid or conjoint tendon impingement may be an important and potentially under-recognized etiology of pain and decreased IR following RSA. Further investigations aimed toward identifying a critical SCD to improve pain and IR may allow surgeons to preoperatively plan component position to improve clinical outcomes after RSA.

Glenoid lateralization and subscapularis repair are independent predictive factors of improved internal rotation after reverse shoulder arthroplasty

PURPOSE

Reverse shoulder arthroplasty (RSA) has shown improvement in clinical outcomes for various conditions, although some authors expressed concern about the restoration of active internal rotation (AIR). The current study assesses preoperative and intraoperative predictive factors of AIR in patients having a Grammont-style RSA with a minimum five year follow-up.

METHODS

We conducted a retrospective multicentric study, including patients operated on with a 155° Grammont-style RSA for cuff-related pathology or primary osteoarthritis with posterior subluxation or an associated cuff tear. Patients were clinically evaluated at a minimum of five year follow-up. Patients with previous surgery or those who had a tendon transfer with the RSA were excluded. Demographic parameters, BMI, preoperative notes, and operative reports were obtained from medical records. AIR was graded according to the constant score system from 0 to 10.

RESULTS

A total of 280 shoulders in 269 patients (mean age at surgery, 74.9 ± 5.9 years) met the inclusion criteria and were analyzed. The average follow-up was 8.1 years (range, 5-16 years). Overall, AIR increased from 4.2 (SD 2.5, range 0 to 10) preoperatively to 5.9 (SD 2.6, range 0 to 10) at final follow-up. At the last follow-up, AIR increased in 56% of cases, was unchanged in 26% and decreased in 18%. In 188 shoulders (67%), internal rotation was functional and allowed patients to reach the level of L3 or higher. Multivariable linear regression found the following preoperative clinical factors predictive of worse AIR after RSA: male gender (ß = -1.25 [-2.10; -0.40]; p = 0.0042) and higher values of BMI (ß = -0.085 [-0.17; -0.0065]; p = 0.048). Two surgical factors were associated with better AIR after RSA: glenoid lateralization with BIO-RSA technique (ß = 0.80 [0.043; 1.56]; p = 0.039) and subscapularis repair (ß = 1.16 [0.29; 2.02]; p = 0.0092).

CONCLUSIONS

With a mean of eight year follow-up (5 to 16 years), internal rotation was functional (≥ L3 level) in 67% of operated shoulders after Grammont-style RSA; however, two patients out of ten had decreased AIR after surgery. Male patients and those with higher BMIs had worse AIR, with glenoid lateralization (using the BIO-RSA technique) and subscapularis repair, as they are predictive of increased AIR after RSA.

LEVEL OF EVIDENCE

Case series, Level IV.

A robotic-assisted simulation of kinematic alignment in TKA leads to excessive valgus and internal rotation in valgus knees

PURPOSE

Strategies to further improve patient satisfaction after total knee arthroplasty include the introduction of new alignment philosophies and more precise instruments such as navigation and robotics. The aim of this study was to investigate the effect of a combination of image-based robotic assistance and the use of modern alignment strategies on the resulting joint line obliquity as well as femoral component rotation and to compare this between varus, neutral and valgus knees.

METHODS

This retrospective study included 200 patients who received a robotic-assisted total knee arthroplasty (MAKO®, Stryker) using functional alignment between 2018 and 2020. The patients were divided into a varus (103 patients), neutral (57 patients) and valgus (40 patients) group. The intraoperatively recorded bone cuts and resulting joint line obliquity were identified and compared to values obtained with a robotic computer simulation of kinematic alignment.

RESULTS

The mean femoral coronal alignment of the varus, neutral and valgus group, respectively, equalled 0.5° (± 1.1°), 1.1° (± 0.8°) and 1.6° (± 0.7°) of valgus with functional alignment and 2.1° (± 2.1°), 4.1° (± 1.7°) and 6.2° (± 1.7°) of valgus with kinematic alignment. The mean femoral axial alignment of the valgus group resulted in 0.8° (± 2.0°) of internal rotation with functional alignment and 3.9° (± 2.8°) of internal rotation with kinematic alignment. Overall, 186 knees (93%) could be balanced while respecting certain safe zones by using functional alignment as opposed to 54 knees (27% and none in the valgus group) when applying kinematic alignment. Kinematic alignment led to a combination of femoral component valgus and internal rotation of more than 3° in 22 valgus knees (55%), 10 neutral knees (18%) and 3 varus knees (3%) compared to none in each group when applying functional alignment with safe zones.

CONCLUSIONS

Robotic-assisted kinematic alignment leads to a combination of excessive valgus and internal rotation of the femoral component in valgus and to a lesser extent also in neutral knees when compared with functional alignment.

LEVEL OF EVIDENCE

IV.

Validity and reliability of the Thai functional internal rotation scale for shoulder arthroplasty

Background

The Functional Internal Rotation Scale is an excellent clinical tool for evaluating patients with shoulder arthroplasty, but it has not been adapted to the Thai version. The objectives of this study were to translate the English version and culturally adapt the Functional Internal Rotation Scale to the Thai version and to examine the psychometric properties of the Thai Functional Internal Rotation Scale among Thai participants having shoulder arthroplasty.

Methods

The Functional Internal Rotation Scale was translated to Thai, including cross-cultural adaptations, following standard guidelines. Psychometric properties were evaluated with shoulder arthroplasty patients. Content validity was evaluated using the content validity index (CVI). Criterion validity was assessed using the Pearson correlation coefficient. An Independent t-test was used to evaluate construct validity. Internal consistency reliability was assessed using Cronbach's alpha coefficient. Intraclass correlation coefficient (ICC) was used to determine test-retest reliability over a 14-day interval.

Results

Of 45 participants, 20 total shoulder arthroplasty (TSA) patients and 25 reverse shoulder arthroplasty (RSA) patients, the majority of participants were female (69%) and retired (91%) with a mean age of 72.9 years (SD 9.1). CVI evaluation was acceptable, with a total CVI of 0.92. The correlation of the Thai Functional Internal Rotation Scale with the Thai version of the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (Thai ASES) and the internal rotation subscale (IR subscale) of the Thai ASES was 0.73 (P < 0.001) and 0.75 (P < 0.001), respectively. For construct validity, TSA patients scored, on average, 10.8 points higher than RSA patients (43.7 vs. 32.9, P < 0.001, 95% confidence interval 6.3-15.3). Cronbach's alpha coefficient of the Thai Functional Internal Rotation Scale was 0.95. The test-retest reliability revealed excellent reliability (ICC 0.99).

Conclusion

The Thai Functional Internal Rotation Scale has good validity and excellent reliability in assessing internal rotation function in Thai shoulder arthroplasty patients.

The posterolateral upslope of a low-conforming insert blocks the medial pivot during a deep knee bend in TKA: a comparative analysis of two implants with different insert conformities

PURPOSE

Tibial insert conformity in total knee arthroplasty (TKA) is of interest due to the potential effect on tibiofemoral kinematics. This study determined differences in anterior-posterior movements of the femoral condyles, pivot locations, and internal tibial rotation in different arcs of flexion for two implants with different insert conformities in kinematically aligned TKA.

METHODS

Twenty-five patients treated with a medial and lateral low-conforming, posterior cruciate ligament (PCL) retaining (LC CR) implant followed by a medial ball-in-socket and flat, lateral PCL sacrificing (B-in-S CS) implant in the contralateral knee underwent single-plane fluoroscopy during a deep knee bend. Analysis following 3D-to-2D image registration determined tibiofemoral kinematics and patients completed validated outcome scores for both knees.

RESULTS

The mean follow-up of 1.6 ± 0.4 years for the knee with the B-in-S CS implant was shorter than the 2.7 ± 1.2 years for the LC CR implant. From 0º to 30º of flexion, a medial pivot occurred with the tibia rotating internally approximately 5º with both implants. From 30º to 90º, the pivot remained medial and internal rotation increased to 10º with the B-in-S CS implant. In contrast, neither femoral condyle moved more than 1 mm with the LC CR implant from 30º to 60º, but from 60º to 90º degrees, a lateral pivot occurred and internal rotation increased. Internal rotation of the tibia on the femur from 0° to maximum flexion occurred about a medial pivot similar to the native knee for the B-in-S CS implant and was 4.5° greater than that of the LC CR implant (10.4° vs 5.9°). There was no difference in the median patient-reported outcome scores between implant designs.

CONCLUSIONS

Tibial insert conformity is a primary determinant of a medial or lateral pivot during a deep knee bend. One explanation for the transition from a medial to lateral pivot between 30º and 60º with the LC CR implant is the chock-block effect of the insert's posterolateral upslope which impedes posterior movement of the lateral femoral condyle. Because there is no posterolateral upslope in the insert of the B-in-S CS implant, the tibia pivots medially throughout flexion similar to the native knee.

LEVEL OF EVIDENCE

Level III.

Latissimus Dorsi and Teres major tendon transfer increases internal rotation torque following lateralized reverse shoulder arthroplasty with subscapularis insufficiency

INTRODUCTION

Limitation of active Internal Rotation (IR) following Reverse Shoulder Arthroplasty (RSA) in patients with massive Rotator Cuff Tears (mRCTs) with subscapularis insufficiency remains a challenge. Recently, RSA with Latissimus dorsi and Teres major (LDTM) transfer in patients with limited active IR has been demonstrated as a reliable treatment option. The purpose of this study was to biomechanically compare the IR torque following LDTM transfer with RSA in mRCT with subscapularis insufficiency to RSA without tendon transfer.

METHODS

Eight cadaveric shoulders were tested (mean age: 64.5 ± 1.9 years) using a custom shoulder testing system that permits loading conditions of mRCT with subscapularis insufficiency. Two conditions were tested and compared. The first condition was RSA alone and the second condition was RSA with LDTM transfer. RSA with a medialized glenoid and lateralized humerus design was used for all specimens. The specimens were tested at 0°, 20° and 40° abduction at three different muscle loads: baseline, double, and triple, while the Teres minor and deltoid loads were kept constant. IR torque was measured with a torque wrench at 0°, 20°, and 40° abduction and 60° and 45° IR positions. Force required for anterior dislocation was measured at 20° abduction and 10° IR position.

RESULTS

RSA with LDTM transfer had significantly higher IR torque at all abductions and muscle loading compared with RSA without transfer (average at all positions; RSA without transfer: 0.80 ± 0.02 Nm, LDTM transfer for all loads: 1.43 ± 0.10 Nm). RSA with LDTM transfer (91.4 ± 3.9 N) needed higher force for anterior dislocation compared to RSA alone (89.4 ± 4.1 N), but there was no significant difference.

CONCLUSION

LDTM transfer with RSA increases IR torque compared to RSA without tendon transfer in a cadaveric model. LDTM transfer with RSA may be a reliable treatment option for patients with mRCT and subscapularis insufficiency who are expected to have limited active IR following RSA.

High and low performers in internal rotation after reverse total shoulder arthroplasty: a biplane fluoroscopic study

BACKGROUND

Internal rotation in adduction is often limited after reverse total shoulder arthroplasty (rTSA), but the origins of this functional deficit are unclear. Few studies have directly compared individuals who can and cannot perform internal rotation in adduction. Little data on underlying 3D humerothoracic, scapulothoracic, and glenohumeral joint relationships in these patients are available.

METHODS

Individuals >1-year postoperative to rTSA were imaged with biplane fluoroscopy in resting neutral and internal rotation in adduction poses. Subjects could either perform internal rotation in adduction with their hand at T12 or higher (high, N = 7), or below the hip pocket (low, N = 8). Demographics, the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and scapular notching grade were recorded. Joint orientation angles were derived from model-based markerless tracking of the scapula and humerus relative to the torso. The 3D implant models were aligned to preoperative computed tomography models to evaluate bone-implant impingement.

RESULTS

The Simple Shoulder Test was highest in the high group (11 ± 1 vs. 9 ± 2, P = .019). Two subjects per group had scapular notching (grades 1 and 2), and 3 high group and 4 low group subjects had impingement below the glenoid. In the neutral pose, the scapula had 7° more upward rotation in the high group (P = .100), and the low group demonstrated 9° more posterior tilt (P = .017) and 14° more glenohumeral elevation (P = .047). In the internal rotation pose, axial rotation was >45° higher in the high group (P ≤ .008) and the low group again had 11° more glenohumeral elevation (P = .058). Large rotational differences within subject groups arose from a combination of differences in the resting neutral and maximum internal rotation in adduction poses, not only the terminal arm position.

CONCLUSIONS

Individuals who were able to perform high internal rotation in adduction after rTSA demonstrated differences in joint orientation and anatomic biases versus patients with low internal rotation. The high rotation group had 7° more resting scapular upward rotation and used a 15°-30° change in scapular tilt to perform internal rotation in adduction versus patients in the low group. The combination of altered resting scapular posture and restricted scapulothoracic range of motion could prohibit glenohumeral rotation required to reach internal rotation in adduction. In addition, inter-patient variation in humeral torsion may contribute substantially to postoperative internal rotation differences. These data point toward modifiable implant design and placement factors, as well as foci for physical therapy to strengthen and mobilize the scapula and glenohumeral joint in response to rTSA surgery.

Computer-assisted analysis of functional internal rotation after reverse total shoulder arthroplasty: implications for component choice and orientation

PURPOSE

Functional internal rotation (IR) is a combination of extension and IR. It is clinically often limited after reverse total shoulder arthroplasty (RTSA) either due to loss of extension or IR in extension. It was the purpose of this study to determine the ideal in-vitro combination of glenoid and humeral components to achieve impingement-free functional IR.

METHODS

RTSA components were virtually implanted into a normal scapula (previously established with a statistical shape model) and into a corresponding humerus using a computer planning program (CASPA). Baseline glenoid configuration consisted of a 28 mm baseplate placed flush with the posteroinferior glenoid rim, a baseplate inclination angle of 96° (relative to the supraspinatus fossa) and a 36 mm standard glenosphere. Baseline humeral configuration consisted of a 12 mm humeral stem, a metaphysis with a neck shaft angle (NSA) of 155° (+ 6 mm medial offset), anatomic torsion of -20° and a symmetric PE inlay (36mmx0mm). Additional configurations with different humeral torsion (-20°, + 10°), NSA (135°, 145°, 155°), baseplate position, diameter, lateralization and inclination were tested. Glenohumeral extension of 5, 10, 20, and 40° was performed first, followed by IR of 20, 40, and 60° with the arm in extension of 40°-the value previously identified as necessary for satisfactory clinical functional IR. The different component combinations were taken through simulated ROM and the impingement volume (mm³) was recorded. Furthermore, the occurrence of impingement was read out in 5° motion increments.

RESULTS

In all cases where impingement occurred, it occurred between the PE inlay and the posterior glenoid rim. Only in 11 of 36 combinations full functional IR was possible without impingement. Anterosuperior baseplate positioning showed the highest impingement volume with every combination of NSA and torsion. A posteroinferiorly positioned 26 mm baseplate resulting in an additional 2 mm of inferior overhang as well as 6 mm baseplate lateralization offered the best impingement-free functional IR (5/6 combinations without impingement). Low impingement potential resulted from a combination of NSA 135° and + 10° torsion (4/6 combinations without impingement), followed by NSA 135° and -20° torsion (3/6 combinations without impingement) regardless of glenoid setup.

CONCLUSION

The largest impingement-free functional IRs resulted from combining a posteroinferior baseplate position, a greater inferior glenosphere overhang, 90° of baseplate inclination angle, 6 mm glenosphere lateralization with respect to baseline setup, a lower NSA and antetorsion of the humeral component. Surgeons can employ and combine these implant configurations to achieve and improve functional IR when planning and performing RTSA.

LEVEL OF EVIDENCE

Basic Science Study, Biomechanics.

Latissimus dorsi and teres major tendon transfer for irreparable anterosuperior rotator cuff tear improves kinematics and internal rotation compared to latissimus dorsi tendon transfer

INTRODUCTION

Latissimus dorsi and teres major (LDTM) tendon transfer has demonstrated better clinical outcomes compared to Latissimus dorsi (LD) transfer for irreparable anterosuperior cuff (subscapularis/supraspinatus) tears; however, the biomechanical effects of these procedures are unknown. Therefore, the objective of this study was to compare kinematics and internal rotation of LDTM transfer to LD transfer for anterosuperior cuff tear.

METHODS

Eight cadaveric shoulders were tested in four conditions; (1) intact, (2) anterosuperior rotator cuff tear, (3) LDTM transfer, and (4) LD transfer. Glenohumeral kinematics and internal rotation at 0°, 30°, and 60° of glenohumeral abduction in the scapular plane were measured. Muscle loading was applied based on physiological cross-sectional area ratios with three muscle loading conditions to simulate potentially increased tension due to the advanced insertion site of the transferred tendons.

RESULTS

The anterosuperior rotator cuff tear leads to a significant superior shift of the humeral head compared to intact at 0° and 30° abduction (p < 0.039). Both the LDTM (p < 0.047) and LD transfers (p < 0.032) significantly shifted the humeral head inferiorly compared to the tear condition.; however, the LDTM transfer shifted the head in the anteroinferior direction compared to the LD transfer at 60° abduction and 30° ER (p < 0.045). Both LDTM and LD transfer significantly increased internal resting rotation (p < 0.008) and maximum internal rotation (p < 0.008) compared to anterosuperior rotator cuff tear and intact at 30° and 60° abduction. LDTM transfer resulted in a significant internal resting rotation compared with the LD transfer at 30° abduction with double muscle loading (p = 0.02). At 0° abduction, the LDTM transfer (p < 0.027) significantly increased maximum internal rotation compared to anterosuperior rotator cuff tear and intact.

CONCLUSION

Although both LDTM and LD tendon transfer improved the abnormal humeral head apex position and internal rotation compared with the tear condition, the LDTM transfer was biomechanically superior to the LD transfer in a cadaveric model.

Predictors of Internal Rotation after Reverse Shoulder Arthroplasty

Objectives

Internal rotation (IR) remains unpredictable following reverse total shoulder arthroplasty (rTSA). This study aimed to determine if increasing IR limits range of motion in other planes, and to determine pre- and intra-operative factors associated with post-operative IR.

Methods

A retrospective analysis of a single surgeon's primary rTSA with a single implant was undertaken, excluding patients with acute fracture or infection. A lesser tuberosity osteotomy (LTO) or subscapularis peel tenotomy was performed and repaired at the surgeon's discretion. One hundred sixty rTSA were included; 142 (88.8%) had documented IR both pre-operatively and at one-year follow-up. Variables were collected to determine their effect on IR at the 1-year follow-up point. A multivariate logistic regression was used to determine independent predictors of sufficient IR.

Results

Average age was 69.8 (range: 55-86) years and 55% (88/160) were female. Preoperatively, 20.4% of patients (29/142) had sufficient IR. This improved to 32.4% (46/142) one year following surgery, p<0.001). Factors associated with sufficient post-operative IR were female sex (p=0.05), decreasing body mass index (p=0.04), pre-operative IR (p=0.01), preoperative external rotation (ER) in adduction (p<0.001), radiographic evidence of LTO healing (p=0.02), increased one-year postoperative forward elevation (p<0.001), and increased one-year postoperative ER (p<0.001). Increased postoperative IR did not adversely affect forward elevation or ER. On multivariate analysis, higher preoperative IR and one-year postoperative forward elevation were independently associated with sufficient one-year postoperative IR.

Conclusion

IR following rTSA continues to be modest and unpredictable. Independent predictors of sufficient post-operative internal rotation were higher preoperative IR and one-year postoperative forward elevation. In a Grammont-style rTSA system, humeral version, glenosphere lateralization, and glenosphere size do not appear to impact IR. Importantly, achieving sufficient IR does not come at the expense of other planes of motion.

Factors affecting internal rotation following total shoulder arthroplasty

Background

Reverse shoulder arthroplasty (RSA) was developed in the late twentieth century to provide a stable arthroplasty option for patients with rotator cuff deficiency arthropathy. Since its inception, there have been changes in materials, design, and positioning. One of the persistent clinical issues has been difficulty with internal rotation (IR) and the associated difficulty with behind the back activities. Implant design, positioning, and the available soft tissues may influence IR after RSA. The purpose of this systematic review is to assess factors that impact IR following RSA.

Methods

The literature search, based on PRISMA guidelines, used 4 databases: Pubmed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials. We included clinical trials that compared different implantation and design modifications and assessed IR.

Results

Of the 617 articles identified in the initial search, 46 satisfied the inclusion criteria. The articles explored multiple factors of RSA and their effects on IR, including humeral and glenoid components and muscle function and integrity. Among humeral factors affecting rotation, there was a broad consensus that: IR decreases as retroversion increases, humeral neck-shaft angle less than 155° improves IR, lateralized humeral offset does not improve IR, and shallow cups improve IR. Insert thickness was not associated with a reproducible effect. Of the studies evaluating the effect of glenoid components, there was majority agreement that glenosphere lateralization improved IR, and there were mixed results regarding the effects of glenosphere size and tilt. Others included one study in each: glenoid overhang, retroversion, and baseplate. One study found an association between teres minor insufficiency and improved IR, with mixed results in the presence of fatty infiltration in both teres minor and subscapularis. Most studies noted subscapularis repair had no effect on IR.

Conclusion

Prosthetic variables affecting IR are not widely studied. Based on the existing literature, evidence is conflicting. More research needs to be undertaken to gain a greater understanding regarding which factors can be modified to improve IR in RSA patients.

The rate and predictors of healing of repaired lesser tuberosity osteotomy in reverse total shoulder arthroplasty

Background

Evidence is building that a functional subscapularis improves function-specifically internal rotation tasks-following reverse total shoulder arthroplasty (rTSA). However, the optimal method for subscapularis repair during rTSA remains unknown with variable healing rates reported. This study aims to investigate the rate of and predictors for healing a lesser tuberosity osteotomy (LTO) following rTSA.

Methods

Following local institutional review board approval, patients with at least one-year follow-up for rTSA managed with an LTO and subsequent repair between March, 2017 and March, 2020 were retrospectively identified. Shoulders were selected for LTO repair based upon preoperative imaging and intraoperative assessment of subscapularis quality. All patients were implanted with a system consisting of a 150° or 155° (constrained) humeral neck-shaft angle and 2.5 to 4.5 millimeters (mm) of glenoid lateralization (Trabecular Metal Reverse Shoulder System; Zimmer Biomet, Warsaw, IN, USA). At a minimum of six months, radiographs were reviewed for an assessment of LTO healing by three independent reviewers. Healing was classified as displaced, fibrous union, or ossified union. For assessing predictors, the repair was considered intact if the LTO fragment was not displaced (fibrous union or ossified union).

Results

Sixty-five rTSA with LTO repair were performed in 64 patients. These patients had an average age of 67.2 years (range, 31-81) and 36 (55.4%; 36/65) were female. At an average follow-up of 15.2 months (range, 8-38), 50 cases (76.9%; 50/65) were classified as having an ossified union. The radiographic healing could not be assessed in a single case. Of the 14 cases without ossific union, 8 (12.3%; 8/65) were displaced and 6 (9.2%; 6/65) were classified as a fibrous union. In logistic regression, only combined humeral liner height predicted LTO displacement (odds ratio = 1.4 [95% confidence interval = 1.1-1.8]; P = .01). Humeral loosening was not found in any cases following LTO.

Conclusion

This analysis demonstrates that radiographic healing of LTO repair is more favorable than published rates of healing after subscapularis tenotomy or peel in the setting of rTSA. Subscapularis management with LTO provides the ability to monitor repair integrity with plain radiographs and a predictable radiographic healing rate. The integrity of subscapularis repair may be influenced by the use of thicker humeral liners. Further investigation is needed to determine the functional impact of a healed subscapularis following rTSA.

Active range of motion of the shoulder: a cross-sectional study of 6635 subjects

Background

Normative data for passive range of motion are well established, but daily living is comprised of active motion. The purpose of this study was to establish normative values for active range of motion of the shoulder across age, sex, and arm. Our hypotheses were that active range of motion of the shoulder (1) decreases with age group, (2) differs between males and females, and (3) differs between the right arm and left arm.

Methods

Shoulder active range of motion was captured with an eight-camera markerless motion capture system. Data were collected for a heterogenous sample of 6635 males and females of all ages. For each subject, 6 shoulder motions were collected with maximum values measured: external rotation, internal rotation, flexion, extension, abduction, and horizontal abduction. Three-way repeated measures analyses were performed, with 2 between-subject factors (age group and sex) and 1 within-subject factor (arm). The unadjusted threshold for statistical significance was α = 0.05.

Results

External rotation decreased with age (approximately 10° decrease from below 30 years to above 60 years). External rotation was approximately 5° greater in the right arm, whereas internal rotation was approximately 5° greater in the left arm. Flexion decreased with age (approximately 15° decrease from below 20 years to above 60 years). For age groups from 10 to 59 years, extension and horizontal abduction were approximately 5° to 10° greater in females than males. Abduction was greater for females than males. Abduction was also greater in younger people (aged 10-29 years) than older people.

Conclusion

In general, active range of motion of the shoulder decreases with age. Sex (male/female) and arm side (right/left) also influence shoulder range of motion.

Identifying the underlying mechanisms responsible for glenohumeral internal rotation in professional baseball pitchers

Background and Hypothesis

Glenohumeral internal rotation deficit has been identified as a significant risk factor for upper-extremity injuries in pitchers across all ages. Humeral retroversion (HR), posterior capsule thickness (PCT), and posterior rotator cuff muscle pennation angle (PA) have been independently associated with internal rotation range of motion (IR ROM); however, these anatomic structures have not been collectively measured in baseball pitchers to determine the underlying mechanisms responsible for IR ROM. Therefore, the purpose of this study was to determine the contributions of HR, PCT, and posterior rotator cuff PA on IR ROM during a preseason evaluation in healthy professional baseball pitchers. The authors hypothesized that HR, PCT, and posterior rotator cuff PA would have a significant contribution to IR ROM.

Methods

This is a cross-sectional study. Healthy professional pitchers from a single organization were recruited at the beginning of the 2021 Major League Baseball Spring Training. Participants received bilateral IR ROM assessment while laying supine with the shoulder at 90 degrees of abduction and the scapula stabilized. Ultrasound imaging was also performed bilaterally to assess HR, PCT, infraspinatus (superficial + deep) PA, and teres minor (superficial + deep) PA. All ultrasound imaging processes were performed utilizing previously published, highly reliable techniques. A stepwise regression was performed, which included both arms to determine the mechanisms of IR ROM.

Results

Overall, 49 pitchers (88 shoulders) with an average age of 22.5 ± 2.2 years were included in the final data analysis. Stepwise linear regression found that only HR and PCT were associated with the preseason IR ROM. There was a moderate relationship between HR and PCT relative to IR ROM (R = 0.535, P < .001).

Conclusion

HR and PCT were found to be the primary mechanisms responsible for the preseason glenohumeral IR ROM. The posterior rotator cuff was not found to be significantly related to IR ROM. Future research evaluating these anatomic structures longitudinally-both acutely and chronically-will help clinicians optimize ROM management throughout the season. As glenohumeral internal rotation deficit can have harmful effects in baseball pitchers, understanding which anatomic structures are most responsible for IR ROM is important for injury prevention and treatment.

Association between sagittal spinal alignment and postoperative shoulder range of motion following reverse total shoulder arthroplasty

BACKGROUND

The range of internal rotation sometimes deteriorates after reverse total shoulder arthroplasty; however, the underlying mechanisms remain unclear. This study aimed to investigate the association between sagittal spinal alignment and internal rotation deterioration after reverse total shoulder arthroplasty.

METHODS

We retrospectively reviewed 52 patients who underwent reverse total shoulder arthroplasty by a single surgeon between October 2014 and December 2018. The sagittal spine was radiographed, and the sagittal spinal alignment was evaluated based on 10 parameters (e.g. C7-HA: the distance between the plumb line from the center of the seventh cervical vertebral body and the center of the hip axis). We divided the patients into two groups, group A (internal rotation deterioration; 23 patients) and B (without internal rotation deterioration; 29 patients). Logistic regression analysis was performed to analyze the association between sagittal spinal alignment and internal rotation deterioration after reverse total shoulder arthroplasty, and a receiver operating characteristic curve was used to analyse the cutoff value of independent variables that was correlated with IR deterioration.

RESULTS

Logistic regression analysis demonstrated the correlation between C7-HA and internal rotation deterioration (odds ratio, 1.95; 95% confidence interval, 1.33-2.84; P < 0.001). The receiver operating characteristic curve suggested that when C7-HA was at least 2.44 cm, it was strongly correlated with deterioration of internal rotation (sensitivity, 91.3%; specificity, 93.1%; P < 0.001; area under the curve, 0.938). Group A was significantly inferior to group B in not only internal rotation but also flexion and abduction.

CONCLUSIONS

This study suggested that a remarkably positive value in C7-HA was a factor that was correlated with deterioration of internal rotation. In addition, the deformation of sagittal spinal alignment would impact on the range of motion after reverse total shoulder arthroplasty.

Ratio between 3D glenohumeral and scapulothoracic motions in individuals without shoulder pain

This study determined the ratio between glenohumeral and three-dimensional scapular motion during arm elevation and lowering in 91 individuals without shoulder pain. Scapular kinematics were assessed using an electromagnetic tracking device. Individuals performed 3 repetitions of elevation and lowering of the arm in the sagittal plane. Two-way ANOVAs (interval: 30-60°, 60-90°, 90-120° x phase: elevation and lowering) and paired t-tests were used for data analysis. For scapular internal/external rotation, lesser scapular internal rotation contribution was found during the 60-90° interval as compared to the 90-60° interval. Lesser scapular external rotation was identified in the 60-30° interval of arm lowering. The ratio was greater during arm elevation (1.89) compared to lowering (1.74) across the entire motion arc. For scapular upward rotation, greater upward rotation contribution was observed during arm elevation at the 30-60° interval, and less scapular downward rotation contribution in the final range of arm lowering. For scapular tilt, lesser scapular posterior tilt contribution during arm elevation was observed compared to arm lowering. The ratios between glenohumeral elevation/lowering and each individual scapulothoracic motion showed either differences between intervals and/or between elevation and lowering during specific intervals in healthy individuals.

Reliability of visual inspection and palpation to assess relative flexibility of the shoulder

INTRODUCTION

Movement compensations during internal rotation of the shoulder can provoke pain. Reliably observing and measuring compensations in the shoulder using visual and palpatory methods can result in more efficacious treatments of shoulder pathology. Despite this, the reliability of these measures and the relationship between them is unknown.

METHODS

Bilateral shoulders of 33 Doctor of Physical Therapy (DPT) students were measured. Two third-year DPT student examiners used visual inspection and physical palpation to identify the first signs of internal rotation (IR) passive stiffness. Measurements were taken and recorded by a third examiner using the GetMyROM (Version 1.1) iPhone application.

RESULTS

Good intra-rater reliability for both examiners was identified for physical palpation (ICC = 0.896, 95% CI = 0.830, 0.936, ICC = 0.901, 95% CI = 0.839, 0.939) and visual inspection (ICC = 0.813, 95% CI = 0.699, 0.884, ICC = 0.782, 95% CI = 0.667, 0.880). Moderate interrater reliability was found between the examiners for physical palpation (ICC = 0.681, 95% CI = 0.479, 0.797) while poor interrater reliability was found between examiners for visual inspection (ICC = 0.481, 95% CI = 0.234, 0.648). The correlation between physical palpation and visual inspection indicated moderate reliability for both examiners (r = 0.815, p = 0.01, r = 0.832, p = 0.01).

CONCLUSION

The findings of this research study indicate that both physical palpation and visual inspection are reliable methods for measuring relative flexibility of shoulder IR when performed by the same examiner. However, the reliability for both methods decreases when performed by different examiners. Additionally, a strong correlation was found between both measures.

Comparing patient-reported outcome measures and physical examination for internal rotation in patients undergoing reverse shoulder arthroplasty: does surgery alter patients' perception of function?

BACKGROUND

The purpose of this study was to evaluate how patients treated with reverse shoulder arthroplasty (RSA) achieve internal rotation (IR) using video assessment and to compare this to patient-reported outcome measures (PROMs).

METHODS

We reviewed 215 preoperative and 657 postoperative videos (3-78 months) for 215 patients who underwent primary RSA, performing IR using the modified vertebral level method. Their functional motion pattern was then grouped into 3 types: type I, could not reach behind their back; type II, able to reach to at least waist level, with assistance; and type III, able to reach to a minimum of waist level in an uninterrupted fashion. Patients completed functional questions (put on a coat, wash back, tuck in a shirt, and manage toileting) and a diagram of perceived IR. Patients' functional motion types were compared to PROM answers. Pre- and postoperative scores were also compared to assess the effect of surgery on patients' perception of IR function.

RESULTS

Patients undergoing RSA will achieve IR in 3 distinct motion patterns. Analysis of self-reported IR indicated statistically significant difference between the 3 functional types of IR (P < .001). Patient-perceived IR was not significantly different between the 3 studied IR functional types (P = .076) in the analysis of preoperative measures but was significantly different in the postoperative setting (P < .001).

CONCLUSION

Patients attempt IR in 3 distinct functional motion patterns. The improvement of IR after RSA is measured better by patient questionnaires than by physical examination.

Steric effects on two inequivalent methyl internal rotations of 3,4-dimethylfluorobenzene

The microwave spectrum of 3,4-dimethylfluorobenzene was measured using a pulsed molecular jet Fourier transform microwave spectrometer operating in the frequency range from 2.0 to 26.5 GHz with the goal of quantifying steric effects on barriers to internal rotation of the two inequivalent methyl groups. Due to these torsional motions, splittings of all rotational transitions into quintets were observed and fitted with residuals close to measurement accuracy. The experimental work was supported by quantum chemical calculations, and the B3LYP-D3BJ/6-311++G(d,p) level of theory yielded accurate optimized geometry parameters to guide the assignment. The three-fold potential values of 456.20(13) cm^-1 and 489.78(15) cm^-1 for the methyl groups at the meta and para position, respectively, deduced from the experiments are compared with the predicted values and those of other toluene derivatives.

Factors influencing functional internal rotation after reverse total shoulder arthroplasty

Background

Functional internal rotation (fIR) of the shoulder is frequently limited after reverse shoulder arthroplasty (RTSA). The objective of this study was to study a cohort of satisfied patients after RTSA who had comparable active mobility except for fIR and to identify factors associated with selective loss of fIR.

Methods

A retrospective cohort study was conducted to compare 2 patient groups with either poor (≤ 2 points in the Constant-Murley score [CS]) or excellent (≥8 points in CS) fIR after RTSA at a minimum follow-up of 2 years. Influencing factors (demographic, surgical or implant related, radiographic parameters) and clinical outcome were analyzed.

Results

Fifty-two patients with a mean age of 72.8 (±9.3) and a mean follow-up of 41 months were included in the IR≤2 group and 63 patients with a mean age of 72.1 (±8.0) and a mean follow-up of 59 months in the IR≥8 group. All patients had undergone RTSA with the same implant type and only 2 different glenosphere sizes (36 and 40) for comparable indications. A multivariate analysis identified the following significant risk factors for poor postoperative fIR: poor preoperative fIR (pts in CS: 3 [range: 2-6] vs. 6 [range: 4-8], P<.0001), smoking (17.3% vs. 6.5%, P = .004), male gender (59.6% vs. 31.7%, P = .002), less preoperative to postoperative distalization of the greater tuberosity (Δ 19.4 mm vs. 22.2 mm, P = .026), a thin humeral insert (≤3 mm: 23.1% vs. 54.8%, P = .039), and a high American Society of Anesthesiologists score (≤ III: 30.8% vs. 14.3%, P = .043). Subscapularis repair status and glenosphere size had no influence on fIR. Clinical outcome scores improved in both groups from preoperatively to last follow-up. The IR≥8 group had overall significantly better outcome scores compared to the IR≤2 group (Δ 9.3% SSV and Δ 9.5% relative CS, P < .0001). There was no difference in CS between the cohorts when the score for fIR was discarded.

Conclusion

Independent risk factors for poor postoperative fIR after RTSA are poor preoperative fIR, smoking, male gender, less preoperative to postoperative distalization of the greater tuberosity, a thin humeral insert height, and a high American Society of Anesthesiologists score. Except for male gender, these factors are modifiable. These findings may be a valuable addition to patient counselling as well as preoperative planning and preoperative and intraoperative decision-making. The relevance of fIR for overall satisfaction is substantiated by this study.

Internal rotation and chlorine nuclear quadrupole coupling in 2-chloro-4-fluorotoluene explored by microwave spectroscopy and quantum chemistry

2-Chloro-4-fluorotoluene was investigated using a combination of molecular jet Fourier transform microwave spectroscopy in the frequency range from 5 to 21 GHz and quantum chemistry. The molecule experiences an internal rotation of the methyl group, which causes fine splittings of all rotational transitions into doublets with separation on the order of a few tens of kHz. In addition, hyperfine effects originating from the chlorine nuclear quadrupole moment coupling its nuclear spin to the end-over-end rotation of the molecule are observed. The torsional barrier was derived using both the rho and the combined-axis-method, giving a value of 462.5(41) cm^-1. Accurate rotational constants and quadrupole coupling constants were determined for the ³⁵Cl and ³⁷Cl isotopologues and compared with Bailey's semi-experimental quantum chemical predictions. The gas phase molecular structure was deduced from the experimental rotational constants supplemented with those calculated by quantum chemistry at various levels of theory. The values of the methyl torsional barrier and chlorine nuclear quadrupole coupling constants were compared with the theoretical predictions and with those of other chlorotoluene derivatives.

The structure and low-barrier methyl torsion of 3-fluorotoluene

The rotational spectra of 3-fluorotoluene and its seven ¹³C isotopic species have been recorded at natural abundance in the frequency range from 4 to 26 GHz using a pulsed molecular jet Fourier transform microwave spectrometer. The molecular structure comprising bond lengths and angles as well as parameters describing the methyl torsion were determined with high accuracy. Due to the very low torsional barrier of 17 cm^-1, the lowest torsional states of the vibrational ground state exhibited large splittings in the spectrum, which were modeled satisfactorily with a modified version of the program XIAM and the program aixPAM, both developed to treat the methyl internal rotation effects. They were also applied to refit the microwave data of 3,4-difluorotoluene to standard deviations close to measurement accuracy.

Muscle activities during shoulder internal rotation differ in arm position: a preliminary quantitative analysis using positron emission tomography

OBJECTIVE

To investigate the muscle activity patterns of the glenohumeral joint during internal rotation both with the arm at 0° and 90° of abduction using 2-deoxy-2-[¹⁸F] fluoro-D-glucose (FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Six healthy male volunteers underwent PET examination after performing active glenohumeral internal rotation exercise using an elastic band both with the arm at 0° and 90° of abduction. As a control, PET scan under resting condition was also performed. The exercise was performed before and after 18 fluorodeoxyglucose injection. Each PET image was fused to the corresponding MRI to identify each muscle. The standardized uptake value (SUV) of each muscle was compared between the two arm positions.

RESULTS

With the arm at 0° of abduction, the SUV increased significantly after exercise both in the middle and inferior 1/3 of the subscapularis, which were significantly higher than that of the superior 1/3 of the subscapularis (P < 0.05). The SUV of the inferior 1/3 of the subscapularis was significantly higher at 90° of abduction than at 0° of abduction and was significantly higher than that of the superior 1/3 at 90° of abduction (P < 0.01). The SUV after exercise in the inferior infraspinatus and teres minor increased.

CONCLUSIONS

The middle and inferior parts of the subscapularis are the main shoulder internal rotators in 0° of abduction, whereas the inferior part of the subscapularis is the main internal rotator in 90° of abduction.

Quantum aspects of torsional vibrations in the HO3H, DO3H and DO3D molecules

The hydrogen trioxide (HT) molecule HOOOH is 1) a prototype for a class of molecules of the form X(ZY)₂ with two equivalent internal tops (ZY) and 2) the second representative of the polyoxides series of the form HO_nH (n ≥ 2). Due to this, it is the subject of close attention of researchers. In this paper, we performed a group theory analysis of the torsional and spin states of the HOOOH, DOOOH, and DOOOD molecules. The relationships have been established between the symmetry species of the C_2V(M) molecular symmetry group to which the HOOOH and DOOOD molecules belong, and the symmetry species of the C₂ and C_S point groups to which the equilibrium configurations of trans- and cis-conformers of the above molecules belong, respectively. 2D PES and 2D surfaces of kinematic coefficients related to torsional vibrations of hydroxyl groups were calculated at the complete basis set (CBS) limit by extrapolating the results of calculations at the MP2/cc-pVTZ and MP2/cc-pVQZ levels of theory. For all the three molecules, the energies of the stationary torsional states were computed using the Fourier method for a numerical solution of the 2D vibrational Schrödinger equation. Symmetry species of torsional states and the values of quantum numbers defining the types of torsional vibrations were found by analyzing the torsional wave functions. The selection rules for transitions between torsional states in the dipole approximation were also formulated.

Internal rotation of the tibial component in total knee arthroplasty can lead to extension deficit

PURPOSE

Stiffness is a common problem following total knee arthroplasty (TKA). Mal-rotated components have been claimed to be the major cause of pain and limited motion after TKA. The present study investigates whether intra-operative intentional malrotation of the tibial component would change in vivo kinematics. The hypothesis is excessive internal rotation of the tibial component would result in postoperative extension deficit.

METHODS

Thirty-one patients were enrolled in this study. After completing bony cuts and proper soft tissue balancing, the femoral and tibial trials were impacted and fixed using small pins. Lateral radiographs were used to measure and compare intraoperative full knee extension during normal and after intentional internal rotation of the tibial component. The extension deficit angles were also compared between the posterior stabilised (PS) and cruciate retaining (CR) implants.

RESULTS

For normal tibial component rotation, the median (interquartile range) extension deficit was 0° (4). The mean tibial trial intentional internal rotation was 21.2° (± 4.5). The median (interquartile range) extension deficit significantly increased to 6° (4) after tibial component internal rotation (p = 0.001). The use of PS spacers resulted in a significantly greater extension deficit after intentional internal rotation 9° (5) compared to that of the CR implant 1° (4) (p = 0.001).

CONCLUSION

Internal rotation of the tibial component in total knee arthroplasty can lead to postoperative extension deficit. This could be attributed to interference with "screw home" mechanism that requires full external rotation of the tibia on the femur. Consequently, this deficit may cause pain and knee stiffness following TKA.

LEVEL OF EVIDENCE

III.

Strain distribution of the anterolateral ligament during internal rotation at different knee flexion angles: A biomechanical study on human cadavers

BACKGROUND

Injuries of the anterolateral ligament (ALL) are fairly common in patients with ruptures of the anterior cruciate ligament (ACL). Before considering repair or reconstruction of the ALL, the lack of knowledge with regard to the biomechanical behavior of this ligament must be considered. The purpose of this study was to analyze the strain of the ALL induced by tibial internal rotation at different flexion angles and find out the strain distribution features.

METHODS

The ALLs of ten fresh-frozen cadaver knees were dissected. All specimens underwent tibial internal rotation from 0° to 25° at 30°, 60°, 90°, and 120° of knee flexion. Strain distribution of the ALL during internal rotation was recorded by digital image correlation (DIC). The overall strain and sub-regional strain were measured.

RESULTS

The strain of the ALL increased with increasing tibial internal rotation. With 25° of internal rotation, the overall strain at each flexion angle was 12.89 ± 2.73% (30°), 15.32 ± 2.50% (60°), 18.94 ± 2.34% (90°), and 20.10 ± 3.27% (120°). The sub-regional strain was significantly different at all flexion angles. The strain of the distal 1/3 of the ALL was the greatest, followed by the middle 1/3, while the proximal 1/3 was the smallest (all P < 0.001).

CONCLUSION

The ALL resisted internal rotation of the tibia by becoming more tense with increasing rotation. A significantly high strain was observed in the distal portion near the tibial insertion site of the ALL, which may suggest that this region is prone to injury with excessive internal rotation.

Correlation between the distance of scapular anterior tilting and the ratio of internal and external rotation angle of shoulder in supine position

[Purpose] This study investigated the relationship between the amount of scapular anterior tilting and the ratio of internal and external rotation of the shoulder in a supine position. [Participants and Methods] Twenty healthy participants (8 females, 12 males) were enrolled in this study. Internal rotation (IR) and external rotation (ER) of the glenohumeral joint were performed in a supine position, and the IR and ER angles were measured using a universal goniometer. The changing distance of scapular anterior tilting was measured by a three-dimensional motion analysis tracking system while participants performed IR and ER in a supine position. Pearson’s correlation coefficient was used to investigate the relationship between the distance of scapular anterior tilting and the ratio of internal and external rotation angle of the shoulder. [Results] The correlation of the degree of scapular anterior tilting with the IR/ER ratio, particularly the IR angle of the shoulder in a supine position, was good to excellent (r=−0.851). [Conclusion] The findings suggest that asymmetry of the IR and ER angles may cause increased scapular anterior tilting in a supine position.

Developing reliable measures of the passive torque-angle relationship for shoulder internal and external rotation: Implications for overhead athletics

OBJECTIVES

1) Thoroughly assess shoulder flexibility by establishing the passive torque-angle relationship for internal and external rotation with the arm in an overhead athletics position (abducted 90°) and 2) test the reliability of four passive torque-angle measures.

DESIGN

Reliability study.

SETTING

Data were collected in a university biomechanics laboratory.

PARTICIPANTS

Bilateral shoulder flexibility of 15 male college students (20.7 ± 1.1 y) was evaluated twice in two sessions over 7-10 days.

MAIN OUTCOME MEASURES

For both ER and IR, reliability was assessed bilaterally (intra-session, inter-session, and inter-tester) for the traditional range of motion measure and three novel kinetic measures: torque at end ROM, resistance onset angle, rotational stiffness. This resulted in 48 total assessments.

RESULTS

Thirty-four assessments had good to excellent reliability (ICC ≥ 0.8), 10 had fair reliability (0.7 ≤ ICC < 0.8), and 4 had poor reliability (ICC< 0.7). Three of the four flexibility measures had a good overall ICC score: ROM (0.83), torque at end ROM (0.84), and resistance onset angle (0.81). The fourth, stiffness, had a fair overall reliability score (0.74).

CONCLUSIONS

The passive torque-angle measures should be assimilated into clinical and research settings to determine the relevance to injury, rehabilitation, and performance.

Correlation between isometric shoulder strength and racket velocity during badminton forehand smash movements: study of valid clinical assessment methods

[Purpose] The purpose of this study was to confirm the correlation between racket velocity during the forehand smash movements with shoulder extensor strength and internal rotator strength in the neutral and abducted positions. [Subjects and Methods] Fourteen collegiate badminton players participated in the study. Measurements were performed shoulder strength, using torque calculated from the upper extremity length and the isometric force, and racket velocity during the forehand smash movements. The shoulder extensor strength and internal rotator strength were measured in the neutral and abducted positions. [Results] The extension torque and internal rotation torque of the shoulder in the neutral position were not significantly correlated with racket velocity. Additionally, correlations between extension torque of the shoulder in the maximum abducted position and racket velocity were insignificant. However, the internal rotation torque of the shoulder in the abducted external rotated position was significantly correlated with racket velocity (r=0.652). [Conclusion] The shoulder internal rotator strength in the abducted external rotated position are suitable measurements for evaluating badminton players.

Can patients manage toileting after reverse total shoulder arthroplasty? A systematic review

PURPOSE

A major concern for patients undergoing reverse total shoulder arthroplasty (RTSA) is managing toileting after surgery. The goals of this systematic review of RTSA studies were to determine the following: (1) the percentage of patients who can manage toileting, (2) their degree of difficulty with toileting, and (3) the percentage of patients who can manage toileting after bilateral versus unilateral RTSA.

METHODS

Medline, EMBASE, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched for studies reporting the ability to manage toileting after RTSA. Six studies with at least 12 months of follow-up were included, yielding 183 patients (105 unilateral RTSA, 78 bilateral RTSA). We pooled patient data and calculated the weighted mean proportion of patients able to manage toileting, those who reported difficulty, and those able to manage toileting after unilateral versus bilateral RTSA. Statistical significance was set at P < 0.05.

RESULTS

Most patients (92%; 95% confidence interval, 87-95%) were able to manage toileting after RTSA. Some degree of difficulty with toileting was reported for 20% of all shoulders. Almost all patients with bilateral RTSA were able to manage toileting with at least one arm (weighted mean proportion 97%; 95% confidence interval, 88-99%). There was no significant difference in the proportion of patients able to manage toileting after unilateral versus bilateral RTSA (P = 0.08). Only 3% of all papers published on the clinical results of RTSA by June 2017 reported upon toileting after the procedure.

CONCLUSIONS

With the available evidence, most patients were able to manage toileting after RTSA, although one-fifth reported some degree of difficulty. Ability to manage toileting was similar after unilateral versus bilateral RTSA. In the future, this variable should be a standard question after shoulder arthroplasty.

LEVEL OF EVIDENCE

IV.

Weight-bearing computed tomography findings in varus ankle osteoarthritis: abnormal internal rotation of the talus in the axial plane

OBJECTIVES

To assess the incidence of abnormal internal rotation of the talus in the axial plane in patients with varus ankle osteoarthritis, and to determine whether this incidence differs from the severity of varus ankle osteoarthritis (moderate versus severe).

MATERIALS AND METHODS

We retrospectively evaluated weight-bearing computed tomography (CT) and plain radiographs of 52 ankles with no abnormalities (control group) and 96 ankles with varus osteoarthritis (varus-OA group), which were further stratified into a moderate-OA subgroup (50 ankles) and a severe-OA subgroup (46 ankles). A new radiographic parameter on weight-bearing CT, the talus rotation ratio, was used to assess the rotation of the talus in the axial plane. The normal range of the talus rotation ratio was defined as the 95% prediction interval for talus rotation ratio values in the control group. Abnormal internal rotation of the talus was defined for talus rotation ratio values above the normal range. We determined the incidence of abnormal internal rotation of the talus in the varus-OA group, moderate-OA subgroup, and severe-OA subgroup.

RESULTS

In the varus-OA group, the incidence of abnormal internal rotation of the talus was 45% (43 ankles), which corresponded to an incidence of 32% (16 ankles) in the moderate-OA subgroup and 59% (27 ankles) in the severe-OA subgroup (p = 0.013).

CONCLUSION

Our study demonstrates that abnormal internal rotation of the talus occurs in patients with varus ankle osteoarthritis, and is more frequently noted in severe than in moderate varus ankle osteoarthritis.

Three-dimensional motion analysis for validation of shoulder internal rotation

BACKGROUND

10% of the points for the Constant-Murley score (CMS) are allocated for the capacity for internal rotation (IR), measured as unassisted active movement of the dorsum of the hand or the thumb to reach different anatomical landmarks. However, there is little information about the validity of this method and no three-dimensional measurement of the degree of IR that is necessary to reach these landmarks.

METHODS

Sixteen volunteers with healthy shoulders were recruited. The degree of IR was defined using the following landmarks as described in the CMS: (1) lateral aspect of thigh, (2) buttock, (3) sacroiliac joint, (4) level of waist, (5) vertebra T12, (6) interscapular. The validity of IR measurement was assessed by simultaneous 3D motion analysis.

RESULTS

Using the thumb as pointer, there were significant increases in IR from 39.3° at position 1 to 80.4° at position 2, followed by 105.1°, 108.6°, 110.1°, and 125.3° at position 3-6. Taking the dorsum of the hand as pointer, there were significant increases in IR between all positions, starting from 71.2° (position 1) and followed by 99.3°, 104.1°, 110.3°, 115.2°, and 119.7° at positions 2 to 6. Comparing the two measurement methods, a significant difference was found for the amount of IR between positions 1 and 2.

CONCLUSION

Measurement of IR as described in the CMS is a suitable method. However, there was an increase of only 10° in IR between positions 3 and 5, which may be hard to measure with a standard goniometer in clinical practice.

A New Reconstructive Technique of the Anterolateral Ligament with Iliotibial Band-Strip

Background:

Anterior cruciate ligament (ACL) reconstruction is a well-established surgical procedure for the correction of ACL ruptures. However, the incidence of instability following ACL reconstruction is substantial. Recent studies have led to greater insight into the anatomy and the radiographic characteristics of the native anterolateral ligament (ALL), along with its possible role in residual instability after ACL reconstruction.

Method:

The current paper describes a lateral extra-articular tenodesis to reconstruct the ALL during ACL procedures, using a short iliotibial band strip. The distal insertion of this strip is left intact on the anterolateral side of the proximal tibia, and the proximal part is fixed at the anatomic femoral insertion of the ALL.

Results:

Our technique avoids the sacrifice of one of the hamstring tendons for the ALL reconstruction. Additionally, there is no interference with the anatomical location or function of the LCL.

Conclusion:

Our technique offers a minimally invasive and nearly complete anatomical reconstruction of the ALL with minimal additional operative time.

Cross-contamination of the fitting parameters in multidimensional tunneling treatments

In this paper we examine the two-dimensional tunneling formalism used previously to fit the hydrogen-transfer and internal-rotation splittings in the microwave spectrum of 2-methylmalonaldehyde in an effort to determine the origin of various counterintuitive results concerning the isotopic dependence of the internal-rotation splittings in that molecule. We find that the cause of the problem lies in a "parameter contamination" phenomenon, where some of the numerical magnitude of splitting parameters from modes with large tunneling splittings "leaks into" the parameters of modes with smaller tunneling splittings. We show that such parameter contamination, which greatly complicates the determination of barrier heights from the least-squares-fitted splitting parameters, will be a general problem in spectral fits using the multi-dimensional tunneling formalism, since it arises from subtle mathematical features of the non-orthogonal framework functions used to set up the tunneling Hamiltonian. Transforming to a physically less intuitive orthonormal set of basis functions allows us to give an approximate numerical estimate of the contamination of tunneling parameters for 2-methylmalonaldehyde by combining a dominant tunneling path hypothesis with results recently given for the hydrogen-transfer-internal-rotation potential function for this molecule.

Evaluation of functional outcomes and preliminary results in a case series of 15 children treated with arthroscopic release for internal rotation contracture of the shoulder joint after Erb's palsy

INTRODUCTION

The purpose of this study was to evaluate shoulder function following minimally invasive subtotal subscapularis muscle and periarticular capsuloligamentous arthroscopic release in children with Erb's palsy.

METHODS

A prospective study was conducted on 15 consecutive children who underwent subtotal subscapularis muscle and periarticular capsuloligamentous arthroscopic release to treat internal rotation contracture of the shoulder joint after Erb's palsy. Age at surgery ranged from 24 to 38 months (average 28.3) (2.4 years). All of the patients were assessed clinically and radiologically preoperatively and postoperatively at regular intervals. The Mallet scoring system was used to analyze the results.

RESULTS

The mean external rotation improved from -24° to +46° (p = 0.001) at the last follow-up. Active internal rotation was preserved in all cases. At the final follow-up, there had been no loss of the external rotation gained and no recurrence of internal rotation contracture of the shoulder, and the mean Mallet score (total) had improved from 11 to 17 points (p = 0.001).

CONCLUSIONS

In children aged from 1 to 3 years, an arthroscopic release procedure alone may successfully restore function and yield a centered glenohumeral joint, which has a beneficial effect on glenoid remodeling.

LEVEL OF EVIDENCE

Level IV.

A retrospective analysis on the correlation between hip pain, physical examination findings, and alpha angle on MR images

BACKGROUND

We aimed to search whether alpha angle, a radiological clue used in the diagnosis of femoroacetabular impingement, is correlated with the presence of hip pain, internal rotation angle, and impingement test results on hip impingement patients (CAM type).

METHODS

Medical records of 334 patients (156 women, 178 men) with an average age of 33.8 ± 8.4 (range 20-50) years were retrospectively studied for the alpha angle of the hip measured on magnetic resonance images (MRI). Hip pain and internal rotation angles as well as results of impingement tests were reviewed.

RESULTS

Hip pain was reported more frequently on the right side (n = 35, 10.5%) compared to the left side (n = 22, 6.6%) (p = 0.047). No difference was observed between the right and left sides regarding alpha angles (p = 0.145), internal rotation angles (p = 0.637), or positivity of impingement test (p = 0.210). Internal rotation angles were significantly higher in cases without hip pain (p < 0.001) and in patients with negative impingement test result (p < 0.001). Internal rotation angle correlated positively with age and negatively with the alpha angle. Alpha angle was increased in cases that report pain, those with an internal rotation angle <20°, or cases with positive impingement test. The pain was more common, internal rotation angle was higher, and positivity for impingement was more frequent if the alpha angle was <55°. Patients with hip pain or positive impingement test or internal rotation angle <20° had increased alpha angles (p < 0.001).

CONCLUSIONS

The pain, impingement test results, and internal rotation angle seem to be associated with alpha angle of the hip measured on MRI in hip impingement patients.

Isolated glenohumeral range of motion, excluding side-to-side difference in humeral retroversion, in asymptomatic high-school baseball players

PURPOSE

Glenohumeral range of motion is correlated with shoulder capsular condition and is thus considered to be predictive of shoulder pathology. However, in throwing athletes, a side-to-side difference in humeral retroversion makes it difficult to evaluate capsular condition on the basis of glenohumeral range of motion measured by using the conventional technique. The purpose of this study was to measure isolated glenohumeral rotation, excluding side-to-side differences in humeral retroversion, in asymptomatic high-school baseball players.

METHODS

A total of 195 high-school baseball players (52 pitchers and 143 position players; median age, 16 years) and 20 high-school non-throwing athletes (median age, 16 years) without any shoulder symptoms were enroled in this study. Glenohumeral external and internal rotations were measured by using both a conventional technique and our ultrasound-assisted technique. This technique, neutral rotation, was standardized on the basis of the ultrasonographically visualized location of the bicipital groove to exclude side-to-side differences in humeral retroversion from the calculated rotation angle. Intra- and inter-observer agreements of rotational measurements were evaluated by using intra-class correlation coefficients (ICCs).

RESULTS

Isolated glenohumeral rotation measurements, excluding side-to-side differences in humeral retroversion, demonstrated excellent intra-observer (ICC > 0.89) and inter-observer (ICC > 0.78) agreements. Isolated glenohumeral internal rotation was significantly less in the dominant shoulder than in the non-dominant shoulder in asymptomatic baseball players (P < 0.001). Isolated glenohumeral external rotation in baseball players was significantly greater than in non-throwing athletes (P < 0.05). In the baseball players, humeral torsion in the dominant shoulder was significantly greater than that in the non-dominant shoulder (P < 0.001), indicating that the retroversion angle was greater in dominant shoulders than in non-dominant shoulders.

CONCLUSIONS

Isolated glenohumeral external and internal rotations can be measured with high intra- and inter-observer reliability with the exclusion of side-to-side differences in humeral retroversion. Capsular and muscular changes in the throwing shoulder may be better evaluated by using our ultrasound-assisted technique.

LEVEL OF EVIDENCE

Cross-sectional study, Level III.

Two-dimensional character of internal rotation of furfural and other five-member heterocyclic aromatic aldehydes

The features of nuclear motion corresponding to the rotation of the formyl group (CHO) are studied for the molecules of furfural and some other five-member heterocyclic aromatic aldehydes by the use of MP2/6-311G** quantum chemical approximation. It is demonstrated that the traditional one-dimensional models of internal rotation for the molecules studied have only limited applicability. The reason is the strong kinematic interaction of the rotation of the CHO group and out-of-plane CHO deformation that is realized for the molecules under consideration. The computational procedure based on the two-dimensional approximation is considered for low lying vibrational states as more adequate to the problem.

The effect of implant configuration and scapula anatomy: A biomechanical study

BACKGROUND

Internal rotation after reverse shoulder arthroplasty is essential to perform fundamental daily living activities. The purpose of this study was to examine the impact of anatomical and implant related factors on impingement-free internal rotation of the glenohumeral joint.

METHODS

CT-scans of 13 human shoulder specimens with implanted reverse shoulder prostheses were carried out and scapula neck length, lateral pillar angle, and implantation height of the metaglene were measured. Internal rotation testing of all specimens was performed by the use of a robot assisted shoulder simulator. Biomechanical variables were analyzed using a three-way ANOVA. Spearman's rank correlations were performed to determine the relationship between biomechanical and anatomical data.

FINDINGS

The maximum internal rotation angle for a 38 mm centric glenosphere and a standard onlay was 93.4(SD 34.9°). The change of the diameter of the glenosphere resulted in no significant increase of the maximum rotation angle (P=0.16), while change of the glenosphere type from concentric to eccentric (P=0.005) as well as the change of the onlay type from standard to a more shallow one (P=0.002) both had a significant effect on the internal rotation. The distance between the inferior rim of the metaglene and the inferior aspect of the glenoid (P=0.21), scapula pillar angle (P=0.13) as well as the scapula neck length (P=0.81) showed no significant correlation with the maximum internal rotation angle.

INTERPRETATION

Implant component selection shows strong influence on the impingement-free internal rotation. The use of an eccentric glenosphere and a shallow humeral cup may improve internal rotation after reverse shoulder arthroplasty.

Anatomical "C"-shaped double-bundle versus single-bundle anterior cruciate ligament reconstruction in pre-adolescent children with open growth plates

PURPOSE

To analyse the clinical, rotational and radiological (MRI) results of paediatric anatomical "C-shaped" double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with anteromedial and posteromedial bundle compared to single-bundle (SB) ACL reconstruction.

METHODS

Between 2008 and 2014, 57 consecutive patients received a paediatric ACL reconstruction with open physis and were allocated into two groups, according to the surgical procedure. Transepiphyseal SB technique was used until 2012 and DB consecutively thereafter. Follow-up consisted of a clinical evaluation with assessment of the International Knee Documentation Committee (IKDC) form, the Lysholm knee score, Tegner activity score, KT-1000 arthrometer evaluation, VAS Scores for satisfaction, MRI and testing of rotational stability using a robotic system.

RESULTS

The mean time from ACL reconstruction to follow-up was 48.1 ± 15.8 in the SB group (n = 17) and 23.1 ± 13.2 in the DB group (n = 16; p < 0.001). No differences were found in the subjective scores. Biomechanically, there were significant differences identified in the KT-1000 (p < 0.03) and total tibial axial rotation (p < 0.04) when evaluating the reconstructed knee only. Ten of 17 (59%) of the SB patients had a Joint Play Area within the acceptable range of the median healthy knee value compared to 100 % in the DB group. Decreased patient satisfaction was associated with increased total tibial axial rotation. No growth disturbance was observed. Overall, 98% of patients were reached and either examined or interviewed. Re-rupture rate was 3 of 21 (14.3%) for DB and 9 of 35 (25.7%) for SB. All but one re-ruptures (92%) happened in the first 16 postoperative months independent of technique.

CONCLUSIONS

The re-rupture rate after pre-adolescent ACL reconstruction is too high both historically and in this mixed cohort. Anatomical transepiphyseal DB ACL reconstruction with open physis may result in a reduction in this re-rupture rate, which may be related to a tighter control of the Joint Play Area. While subjective clinical results were similar between SB and DB, decreased patient satisfaction was associated with increased total tibial axial rotation in the entire cohort. Despite the need for two transepiphyseal tunnels in the DB technique, there did not appear to be an increased risk in growth plate disturbance. Transepiphyseal DB ACL reconstruction appears to be a reasonable alternative to current techniques in pre-adolescent children with an ACL rupture.

LEVEL OF EVIDENCE

IV.

Hyper extension-internal rotation (HERI): A new test for anterior gleno-humeral instability

BACKGROUND

Anterior shoulder dislocation causes injury to the inferior gleno-humeral ligament (IGHL) and capsule. Clinical manoeuvres currently used to evaluate the IGHL test for, and may induce, apprehension. We developed the hyper extension-internal rotation (HERI) test to assess the IGHL and inferior capsule without causing apprehension or inducing a risk of gleno-humeral dislocation.

HYPOTHESIS

The HERI test is easy to perform and reproducible, induces no risk of gleno-humeral dislocation during the manoeuvre, and causes no apprehension in the patients.

MATERIAL AND METHODS

We studied 14 fresh cadaver shoulders. Each specimen was positioned supine with the lateral edge of the scapula on the table and the upper limb hanging down beside the table under the effect of gravity. This position produced hyperextension and internal rotation of the gleno-humeral joint. For each shoulder, the range of extension (°) was measured before and after isolated IGHL section. Then, we performed the HEIR test in 50 patients with chronic unilateral anterior gleno-humeral instability and we compared the range of extension between the normal and abnormal sides.

RESULTS

In the cadaver study, isolated IGHL section increased the angle of extension by a mean of 14.5° (11°-18°) compared to the pre-injury values. In the clinical study, the mean difference in extension angles between the normal and abnormal sides was 14.5°. The patients reported no apprehension during the HERI test.

CONCLUSION

The angle of extension increases after section or injury of the IGHL in cadaver specimens and patients, respectively. When the inferior capsule and IGHL are damaged, the angle of extension increases compared to the normal side. Lesions to these structures can be evaluated clinically by performing the HERI test.

LEVEL OF EVIDENCE

III.

Does restriction of glenohumeral horizontal adduction reflect posterior capsule thickening of the throwing shoulder?

[Purpose] Glenohumeral posterior capsule tightness possibly relates to posterior capsule thickness (PCT). The purpose of the current study was to analyze the relationships between PCT and glenohumeral range of motion (ROM) in horizontal adduction (HAdd) and internal rotation (IR). [Subjects and Methods] This study recruited 39 healthy collegiate baseball players. We measured PCT by using ultrasonography and ROM of the glenohumeral joint of the throwing shoulder by using a digital inclinometer. Pearson’s correlation coefficients were calculated between PCT and HAdd or IR ROM. [Results] There was no correlation between PCT and HAdd ROM, but PCT was significantly correlated with IR ROM. [Conclusion] This result indicates that posterior shoulder capsule tightness only relates to IR ROM, and that restricted HAdd ROM might reflect tightness of other tissue, such as the posterior deltoid.

The external rotation immobilisation does not reduce recurrence rates or improve quality of life after primary anterior shoulder dislocation: a systematic review and meta-analysis

PURPOSE

Conducting a systematic review and meta-analysis of prospective randomised controlled trials directly comparing (1) the rates of recurrence and (2) patient-based quality-of-life assessments after the external rotation (ER) or internal rotation (IR) immobilisation after primary anterior shoulder dislocation.

METHODS

PubMed, EMBASE, the Cochrane Library and ISI Web of Science were searched up to January 2013, using the Boolean operators as follows: (bankart lesion OR shoulder anterior dislocation) AND ((external rotation AND internal rotation) OR immobilisation). All prospective randomised controlled trials directly comparing recurrence rate and patient-based quality-of-life assessments between the ER and IR immobilisations were retrieved. No limitation of the language or publication year existed in our analysis.

RESULTS

Seven of 896 studies involving 663 patients were included, 338 in the ER group and 325 in the IR group. No significant difference was observed in the recurrence rate at all ages (risk ratio (RR)=0.65; 95% confidence interval, 0.41-1.03; p=0.067), at the age stratum of ≤30 years (RR=0.70; 95% confidence interval, 0.38-1.29; p=0.250) and >30 years (RR=0.86; 95% confidence interval, 0.38-1.97; p=0.722). Four trials adopted quality-of-life assessments, using the Constant-Murlay functional scoring system, the Rowe scoring system, the Western Ontario Shoulder Instability index (WOSI), the Disabilities of arm, shoulder and hand (DASH) and the American Shoulder and Elbow Surgeons evaluation form (ASES). Only one trial demonstrated borderline statistical significance (p=0.05) and probable superiority of the ER group based on the ASES. No significant difference was observed in other three trials.

CONCLUSION

Based on the results of our analysis, the ER immobilisation could not reduce the rates of recurrence after primary anterior shoulder dislocation or improve the quality of life compared with the IR immobilisation. More rigorous and adequately powered prospective randomised controlled trials with long-term follow-ups are required to elucidate a more objective outcome.