Lower Trapezius and Latissimus Dorsi Transfer relieve Teres Minor Activity into the Physiological Range in Collin D Irreparable Posterosuperior Massive Rotator Cuff Tears: A Biomechanical Analysis

BACKGROUND

Tendon transfers are established techniques to regain external rotation mobility in patients suffering from an irreparable, posterosuperior massive rotator cuff tear (MRCT). Posterosuperior MRCT with intact teres minor (Type D MRCT) can lead to excessive teres minor loading to maintain external rotation. We hypothesize that tendon transfers are effective in relieving teres minor loading in Type D MRCTs. Our aim was to biomechanically assess muscle synergism with latissimus dorsi (LD-Transfer) and lower trapezius (LT-Transfer) tendon transfer during external rotation at different abduction heights.

METHODS

Using musculoskeletal modeling, we analyzed and compared the moment arm, muscle torque and muscle activity between a healthy and Type D MRCT pathological model with and without the LD- or LT-Transfer at infraspinatus and teres minor insertion sites. Output measures were analyzed during external rotation at different abduction angles and 10 to 50N resistance against external rotation. We assessed its impact on teres minor loading in a Type D MRCT. Morphological variations were parameterized using the critical shoulder angle and the acromiohumeral distance to address variations among patients.

RESULTS

Both transfer types reduced teres minor torque and activity significantly, reaching physiological state at 40N external resistance (p<0.001), with insertion to infraspinatus site being more effective than teres minor site (p<0.001). External rotation moment arms of LD-Transfer were larger than LT-Transfer at 90° abduction (25.1±0.8mm vs. 21.2±0.6mm, p<0.001) and vice versa at 0° abduction (17.4±0.5mm vs. 24.0±0.2mm, p<0.001). While the healthy infraspinatus was the main external rotator in all abduction angles (50-70% torque), a Type D MRCT resulted in a 70-90% increase of teres minor torque and an up to sevenfold increase in its activity leading to excessive loadings beyond 10N resistance against external rotation. Varying the critical shoulder angle and the acromiohumeral distance led to minor variations in muscle moment arm and muscle activity.

CONCLUSION

We identified biomechanical efficacy of both tendon transfers in Type D MRCT regarding teres minor load relieve and superior performance of the transfers at the infraspinatus insertion site.

Functional and Radiologic Outcomes of Degenerative Versus Traumatic Full-Thickness Rotator Cuff Tears Involving the Supraspinatus Tendon

BACKGROUND

Arthroscopic rotator cuff repair (ARCR) is among the most commonly performed orthopaedic procedures. Several factors-including age, sex, and tear severity-have been identified as predictors for outcome after repair. The influence of the tear etiology on functional and structural outcome remains controversial.

PURPOSE

To investigate the influence of tear etiology (degenerative vs traumatic) on functional and structural outcomes in patients with supraspinatus tendon tears.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing ARCR from 19 centers were prospectively enrolled between June 2020 and November 2021. Full-thickness, nonmassive tears involving the supraspinatus tendon were included. Tears were classified as degenerative (chronic shoulder pain, no history of trauma) or traumatic (acute, traumatic onset, no previous shoulder pain). Range of motion, strength, the Subjective Shoulder Value, the Oxford Shoulder Score (OSS), and the Constant-Murley Score (CMS) were assessed before (baseline) and 6 and 12 months after ARCR. The Subjective Shoulder Value and the OSS were also determined at the 24-month follow-up. Repair integrity after 12 months was documented, as well as additional surgeries up to the 24-month follow-up. Tear groups were compared using mixed models adjusted for potential confounding effects.

RESULTS

From a cohort of 973 consecutive patients, 421 patients (degenerative tear, n = 230; traumatic tear, n = 191) met the inclusion criteria. The traumatic tear group had lower mean baseline OSS and CMS scores but significantly greater score changes 12 months after ARCR (OSS, 18 [SD, 8]; CMS, 34 [SD,18] vs degenerative: OSS, 15 [SD, 8]; CMS, 22 [SD, 15]) (P < .001) and significantly higher 12-month overall scores (OSS, 44 [SD, 5]; CMS, 79 [SD, 9] vs degenerative: OSS, 42 [SD, 7]; CMS, 76 [SD, 12]) (P≤ .006). At the 24-month follow-up, neither the OSS (degenerative, 44 [SD, 6]; traumatic, 45 [SD, 6]; P = .346) nor the rates of repair failure (degenerative, 14 [6.1%]; traumatic 12 [6.3%]; P = .934) and additional surgeries (7 [3%]; 7 [3.7%]; P = .723) differed between groups.

CONCLUSION

Patients with degenerative and traumatic full-thickness supraspinatus tendon tears who had ARCR show satisfactory short-term functional results. Although patients with traumatic tears have lower baseline functional scores, they rehabilitate over time and show comparable clinical results 1 year after ARCR. Similarly, degenerative and traumatic rotator cuff tears show comparable structural outcomes, which suggests that degenerated tendons retain healing potential.

Glenoid component placement in reverse shoulder arthroplasty assisted with augmented reality through a head-mounted display leads to low deviation between planned and postoperative parameters

BACKGROUND

Navigated augmented reality (AR) through a head-mounted display (HMD) may lead to accurate glenoid component placement in reverse shoulder arthroplasty (RSA). The purpose of this study is to evaluate the deviation between planned, intra- and postoperative inclination, retroversion, entry point, depth, and rotation of the glenoid component placement assisted by a navigated AR through HMD during RSA.

METHODS

Both shoulders of 6 fresh frozen human cadavers, free from fractures or other bony pathologies, were used. Preoperative computed tomography (CT) scans were used for the 3-dimensional (3D) planning. The glenoid component placement was assisted using a navigated AR system through an HMD in all specimens. Intraoperative inclination, retroversion, depth, and rotation were measured by the system. A postoperative CT scan was performed. The pre- and postoperative 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postoperative inclination, retroversion, entry point, depth, and rotation of the glenoid component placement. Additionally, a comparison between intra- and postoperative values was calculated. Outliers were defined as >10° inclination, >10° retroversion, >3 mm entry point.

RESULTS

The registration algorithm of the scapulae prior to the procedure was correctly completed for all cases. The deviations between planned and postoperative values were 1.0° ± 0.7° for inclination, 1.8° ± 1.3° for retroversion, 1.1 ± 0.4 mm for entry point, 0.7 ± 0.6 mm for depth, and 1.7° ± 1.6° for rotation. The deviation between intra- and postoperative values were 0.9° ± 0.8° for inclination, 1.2° ± 1.1° for retroversion, 0.6 ± 0.5 mm for depth, and 0.3° ± 0.2° for rotation. There were no outliers between planned and postoperative parameters.

CONCLUSION

In this study, the use of a navigated AR system through an HMD for RSA led to low deviation between planned and postoperative values and between intra- and postoperative parameters.

Massive rotator cuff tears with short tendon length can be successfully repaired using synthetic patch augmentation

BACKGROUND

Choosing the optimal treatment for massive rotator cuff tears (MRCTs) still poses a surgical problem. In MRCTs with good muscle quality, but short tendon length, nonaugmented repairs lead to high failure rates of up to 90%. The aim of the study was to evaluate midterm clinical and radiologic outcomes of massive rotator cuff tears with good muscle quality, but short tendon length, which were repaired with synthetic patch augmentation.

METHODS

A retrospective study of patients who underwent arthroscopic or open rotator cuff repairs with patch augmentation between 2016 and 2019 was performed. We included patients older than 18 years, who presented with an MRCT confirmed by an magnetic resonance imaging (MRI) arthrogram showing good muscle quality (Goutallier ≤ II) and short tendon length (length <15 mm). Constant-Murley score (CS), Subjective Shoulder Value (SSV), and range of motion (ROM) were compared pre- and postoperatively. We excluded patients older than 75 years or with presence of rotator cuff arthropathy Hamada stage ≥2a. Patients were followed up for 2 years minimum. Clinical failures were defined by reoperation, forward flexion <120° or a relative CS < 70. Structural integrity of the repair was assessed using an MRI scan. Comparison between different variables and outcomes was performed using Wilcoxon-Mann-Whitney and χ2 tests.

RESULTS

Fifteen patients (mean age 57 years, 13 [86.7%] male, 9 [60%] right shoulders) were reevaluated with a mean follow-up of 43.8 months (27-55 months). There was a significant improvement in the absolute CS (from 33 to 81 points, P = .03), the relative CS (from 41% to 88%, P = .04), the SSV (from 31% to 93%, P = .007), and forward flexion (from 111° to 163°, P = .004) but not in external rotation (from 37° to 38°, P = .5). There were 3 clinical failures (1 atraumatic, 2 traumatic) with reoperations (2 reverse total shoulder arthroplasties and 1 refixation). Structurally, there were 3 Sugaya grade 4 and 5 Sugaya grade 5 reruptures resulting in a retear rate of 53%. The presence of a complete or partial rerupture was not associated with inferior outcomes compared with intact cuff repairs. There were no correlations between the grade of retraction, muscle quality, or rotator cuff tear configuration and rerupture or functional outcomes.

CONCLUSION

Patch augmented cuff repair leads to a significant improvement of functional and structural outcomes. Partial reruptures were not associated with inferior functional outcomes. Prospective randomized trials are needed to confirm the results found in our study.

How to treat stiffness after proximal humeral fractures?

Shoulder stiffness is a frequent complication after proximal humeral fractures treated with or without surgery. Shoulder stiffness is associated with high rates of absence from work and a significant financial burden for the healthcare system. Secondary stiffness is characterized by additional extracapsular adhesions, including subacromial, subcoracoid, and subdeltoid spaces, usually derived from post-fracture or post-surgical extraarticular hematomas. Several secondary causes may coexist with capsular and extracapsular adhesions decreasing the shoulder motion, such as malunion, nonunion, metalwork failure, infection, and osteoarthritis, among others. Conservative treatment, usually prescribed for primary shoulder stiffness, has shown unfavorable results in secondary stiffness, and surgical intervention may be required. Surgical interventions need to be patient-specific. Usually, open or arthroscopic fibro-arthrolysis and subacromial release are performed, together with plate removal and biceps tenotomy/tenodesis. In severe osteoarthritis, shoulder replacement may be indicated. Ruling out infection is recommended in every case.

Current concepts in chronic traumatic anterior shoulder instability

Chronic traumatic anterior shoulder instability can be defined as recurrent trauma-associated shoulder instability requiring the assessment of three anatomic lesions: a capsuloligamentous and/or labral lesion; anterior glenoid bone loss and a Hill-Sachs lesion. Surgical treatment is generally indicated. It remains controversial how risk factors should be evaluated to decide between a soft-tissue, free bone-block or Latarjet-type procedure. Patient risk factors for recurrence are age; hyperlaxity; competitive, contact and overhead sports. Trauma-related factors are soft tissue lesions and most importantly bone loss with implications for treatment. Different treatment options are discussed and compared for complications, return to sports parameters, short- and long-term outcomes and osteoarthritis. Arthroscopic Bankart and open Latarjet procedures have a serious learning curve. Osteoarthritis is associated with the number of previous dislocations as well as surgical techniques. Latarjet-type procedures have the lowest rate of dislocation recurrence and if performed correctly, do not seem to increase the risk of osteoarthritis.

Deep-Learning-Based Segmentation of the Shoulder from MRI with Inference Accuracy Prediction

Three-dimensional (3D)-image-based anatomical analysis of rotator cuff tear patients has been proposed as a way to improve repair prognosis analysis to reduce the incidence of postoperative retear. However, for application in clinics, an efficient and robust method for the segmentation of anatomy from MRI is required. We present the use of a deep learning network for automatic segmentation of the humerus, scapula, and rotator cuff muscles with integrated automatic result verification. Trained on N = 111 and tested on N = 60 diagnostic T1-weighted MRI of 76 rotator cuff tear patients acquired from 19 centers, a nnU-Net segmented the anatomy with an average Dice coefficient of 0.91 ± 0.06. For the automatic identification of inaccurate segmentations during the inference procedure, the nnU-Net framework was adapted to allow for the estimation of label-specific network uncertainty directly from its subnetworks. The average Dice coefficient of segmentation results from the subnetworks identified labels requiring segmentation correction with an average sensitivity of 1.0 and a specificity of 0.94. The presented automatic methods facilitate the use of 3D diagnosis in clinical routine by eliminating the need for time-consuming manual segmentation and slice-by-slice segmentation verification.

Effect of PARP-1 Inhibition on Rotator Cuff Healing: A Feasibility Study Using Veliparib in a Rat Model of Acute Rotator Cuff Repair

BACKGROUND

PARP-1 (poly[ADP-ribose]) was shown to influence the inflammatory response after rotator cuff tear, leading to fibrosis, muscular atrophy, and fatty infiltration in mouse rotator cuff degeneration. So far, it is not known how PARP-1 influences enthesis healing after rotator cuff tear repair.

HYPOTHESIS/PURPOSE

This study aimed to examine the feasibility of oral PARP-1 inhibition and investigate its influence on rat supraspinatus enthesis and muscle healing after rotator cuff repair. The hypothesis was that oral PARP-1 inhibition would improve enthesis healing after acute rotator cuff repair in a rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 24 Sprague-Dawley rats, the supraspinatus tendon was sharply detached and immediately repaired with a single transosseous suture. The rats were randomly allocated into 2 groups, with the rats in the inhibitor group receiving veliparib with a target dose of 12.5 mg/kg/d via drinking water during the postoperative recovery period. The animals were sacrificed 8 weeks after surgery. For the analysis, macroscopic, biomechanical, and histologic methods were used.

RESULTS

Oral veliparib was safe for the rats, with no adverse effects observed. In total, the inhibitor group had a significantly better histologic grading of the enthesis with less scar tissue formation. The macroscopic cross-sectional area of the supraspinatus muscles was 10.5% higher (P = .034) in the inhibitor group, which was in agreement with an 8.7% higher microscopic muscle fiber diameter on histologic sections (P < .0001). There were no statistically significant differences in the biomechanical properties between the groups.

CONCLUSION

This study is the first to investigate the influence of PARP-1 inhibition on healing enthesis. On the basis of these findings, we conclude that oral veliparib, which was previously shown to inhibit PARP-1 effectively, is safe to apply and has beneficial effects on morphologic enthesis healing and muscle fiber size.

CLINICAL RELEVANCE

Modulating the inflammatory response through PARP-1 inhibition during the postoperative healing period is a promising approach to improve enthesis healing and reduce rotator cuff retearing. With substances already approved by the Food and Drug Administration, PARP-1 inhibition bears high potential for future translation into clinical application.

Residual stability of the distal radioulnar joint following ulnar styloid fracture: influence of the remnant distal radioulnar ligaments

Clinical studies suggest that even untreated basal ulnar styloid fractures may not affect patient outcomes. This may be due to the remaining parts of the distal radioulnar ligament still attached providing sufficient residual stability of the distal radioulnar joint. We tested this hypothesis in a biomechanical cadaveric model. Dorsopalmar translation of the distal radioulnar joint and forearm rotation were measured. Seventeen specimens were tested after a simulated ulnar styloid fracture including the fovea, followed by transection of the remaining palmar (n = 9) or dorsal (n = 8) portions of the distal radioulnar ligament and finally with all remnants transected. Rotation and translation both increased significantly after the final transection compared with the foveal fracture. The increase in translation was larger after transection of the dorsal remnants. We conclude that in an ulnar styloid fracture including the fovea, some ligament components are still attached to the ulnar head, giving residual stability to the distal radioulnar joint.

Patient-specific instrumentation reduces deviations between planned and postosteotomy humeral retrotorsion and height in shoulder arthroplasty

BACKGROUND

Patient-specific instrumentation (PSI) may potentially improve humeral osteotomy in shoulder arthroplasty. The purpose of this study was to compare the deviation between planned and postosteotomy humeral inclination, retrotorsion, and height in shoulder arthroplasty, using PSI vs. standard cutting guides (SCG).

METHODS

Twenty fresh-frozen cadaveric specimens were allocated to undergo humeral osteotomy using either PSI or SCG, such that the 2 groups have similar age, gender, and side. Preosteotomy computed tomography (CT) scan was performed and used for the 3-dimensional (3D) planning. The osteotomy procedure was performed using a PSI designed for each specimen or an SCG depending on the group. A postosteotomy CT scan was performed. The preosteotomy and postosteotomy 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postosteotomy inclination, retrotorsion, and height. Outliers were defined as cases with 1 or more of the following deviations: >5° inclination, >10° retrotorsion, and >3 mm height. The deviation and outliers in inclination, retrotorsion, and height were compared between the 2 groups.

RESULTS

The deviations between planned and postosteotomy parameters were similar among the PSI and SCG groups for inclination (P = .260), whereas they were significantly greater in the SCG group for retrotorsion (P < .001) and height (P = .003). There were 8 outliers in the SCG group, compared with only 1 outlier in the PSI group (P = .005). Most outliers in the SCG group were due to deviation >10° in retrotorsion.

CONCLUSION

After 3D planning, PSI had less deviation between planned and postosteotomy humeral retrotorsion and height, relative to SCG.

A biomechanical study comparing the mean load to failure of two different osteosynthesis techniques for step-cut olecranon osteotomy

Background

Olecranon osteotomies are frequently used to expose distal humeral intraarticular fractures. The step-cut olecranon osteotomy (SCOOT) is an augmented version of the oblique olecranon osteotomy, which has recently been evaluated biomechanically with tension band wiring (TBW) fixation. However, complications with TBW are common. In this study, we, therefore, compared the mean load to failure of TBW with compression screws for SCOOT fixation. We hypothesized a higher load to failure for the compression screw group.

Methods

We performed a SCOOT on 36 Sawbones. Eighteen were fixed with TBW, and another 18 with two compression screws. The humeroulnar joint was simulated using an established test setup, which allows the application of triceps traction force through a tendon model to the ulna, while the humeroulnar joint is in a fixed position. Eight models of each fixation group were tested at 20°, and eight at 70° of flexion by isometrical loading until failure, which was defined as either a complete fracture or gap formation of more than 2 mm at the osteotomy site.

Results

At 20° of flexion, mean load to failure was similar between the TBW group (1360 ± 238 N) and the compression screw group (1401 ± 261 N) (P = .88). Also, at 70° of flexion, the mean load to failure was similar between the TBW group (1398 ± 215 N) and the compression screw group (1614 ± 427 N) (P = .28).

Conclusions

SCOOTs fixed with TBW and compression screws showed similar loads to failure. A SCOOT fixed with compression screws might be a valuable alternative for surgeons when treating intraarticular distal humeral fractures. However, future in vivo studies are necessary to confirm our results in a clinical setting.

Nonoperative and Operative Soft-Tissue, Cartilage, and Bony Regeneration and Orthopaedic Biologics of the Shoulder: An Orthoregeneration Network (ON) Foundation Review

Orthoregeneration is defined as a solution for orthopaedic conditions that harnesses the benefits of biology to improve healing, reduce pain, improve function, and optimally, provide an environment for tissue regeneration. Options include drugs, surgical intervention, scaffolds, biologics as a product of cells, and physical and electro-magnetic stimuli. The goal of regenerative medicine is to enhance the healing of tissue after musculoskeletal injuries as both isolated treatment and adjunct to surgical management, using novel therapies to improve recovery and outcomes. Various orthopaedic biologics (orthobiologics) have been investigated for the treatment of pathology involving the shoulder including the rotator cuff tendons, glenohumeral articular cartilage, glenoid labrum, the joint capsule, and bone. Promising and established treatment modalities include hyaluronic acid (HA); platelet-rich plasma (PRP) and platelet rich concentrates (PRC); bone marrow aspirate (BMA) comprising mesenchymal stromal cells (MSCs alternatively termed medicinal signaling cells and frequently, misleadingly labelled "mesenchymal stem cells"); MSC harvested from adipose, umbilical, or placental sources; factors including vascular endothelial growth factors (VEGF), basic fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), transforming growth factor-beta (TGFβ), bone morphogenic protein (BMP), and matrix metalloproteinases (MMPs); prolotherapy; pulsed electromagnetic field therapy; microfracture and other marrow-stimulation techniques; biologic resurfacing using acellular dermal allografts, allograft Achilles tendons, allograft lateral menisci, fascia lata autografts, and porcine xenografts; osteochondral autograft or allograft); and autologous chondrocyte implantation (ACI). Studies involving hyaluronic acid, platelet rich plasma, and medicinal signaling cells of various origin tissues have shown mixed results to-date as isolated treatments and as surgical adjuncts. Despite varied results thus far, there is great potential for improved efficacy with refinement of current techniques and translation of burgeoning preclinical work. LEVEL OF EVIDENCE: Level V, expert opinion.

What's the best surgical repair technique of an ulnar styloid fracture? A biomechanical comparison of different techniques

INTRODUCTION

8-10% of all Ulnar styloid fractures (USF) accompanying distal radius fractures are addressed surgically. The surgical fixation has to counteract forces of translation and rotation acting on the distal radioulnar joint (DRUJ). The different technics used were never compared biomechanically. Our study aims to compare the effects of different techniques of USF fixation on the forearm rotation and the dorsal-palmar (DP)-translation of the DRUJ.

MATERIAL AND METHODS

9 forearm specimens were mounted on a custom testing system. Load was applied for Pronosupination and DP-translation with the forearm placed in neutral position, pronation and supination. The positional change of the DRUJ was measured using a MicroScribe. Six different, sequential conditions were tested in the same specimen: intact, USF and 4 repair techniques (2 K-wire, tension band wiring (TBW), headless compression screw, suture anchor).

RESULTS

The USF significantly increased DP-translation and pronosupination compared to the intact condition. The DP-translation in neutral was reduced significantly with all four techniques compared to the USF condition. TBW and suture anchor also showed a significant difference to the K-wire fixation. In supination only the TBW and suture anchor significantly decreased DP-Translation. The rotational stability of the DRUJ was only restored by the K-wire fixation and the TBW.

CONCLUSIONS

All four USF repair techniques partially restored translational stability; however, only K-wire fixation and TBW techniques restored rotational stability. TBW was biomechanically superior to the other techniques as it restored translational stability and rotational stability.

Cell lineage tracing and functional assessment of supraspinatus tendon healing in an acute repair murine model

Rotator cuff supraspinatus tendon injuries are common with high rates of anatomic failure after surgical repair. The purpose of the study was to define clinically relevant features of a mouse model of supraspinatus tendon injury to determine painful, functional, and structural outcomes; we further investigated two cell populations mediating healing using genetic lineage tracing after full detachment and repair of the supraspinatus tendon in mice. The pain was assessed using the mouse grimace scale and function by gait analysis and tensile testing. Histological and microCT analyses were used to determine enthesis/tendon and bone structure, respectively. Lineage tracing was carried out using inducible Cre lines for ScxCreERT2 (tendon cells) and αSMACreERT2 (myofibroblasts and mesenchymal progenitors). Mice only expressed pain transiently after surgery despite long-term impairment of functional and structural properties. Gait, tensile mechanical properties, and bone properties were significantly reduced after injury and repair. Lineage tracing showed relatively few Scx ^lin tendon cells while αSMA ^lin cells contributed strongly to scar formation. Despite surgical reattachment of healthy tendon, lineage tracing revealed poor preservation of supraspinatus tendon after acute injury and loss of tendon structure, suggesting that tendon degeneration is also a key impediment of successful rotator cuff repair. Scar formation after surgery is mediated largely by αSMA ^lin cells and results in permanently reduced functional and structural properties.

Evaluation of the Circles Measurement and the ABC Classification of Acromioclavicular Joint Injuries

BACKGROUND

Acromioclavicular joint (ACJ) injuries are common. Despite this, it remains unclear how best to assess, classify, and manage these cases. A simple, reliable, valid, and accurate radiographic parameter to measure ACJ displacement would allow improved consistency of diagnosis and subsequent treatment pathways.

PURPOSE

To evaluate "the circles measurement" and associated "ABC classification" as a tool for assessing ACJ displacement and injury classification.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The circles measurement is taken from a lateral Alexander radiograph of the shoulder. The measurement is the center-to-center distance between 2 circles drawn to define the lateral extent of the clavicle and the anteromedial extent of the acromion; it is independent of the displacement plane, judging total ACJ displacement in any direction rather than trying to quantify vertical and/or horizontal displacement. When utilized clinically, the circles measurement is a single measurement calculated as the difference between values recorded for the injured and uninjured sides. Validation of the circles measurement was performed using lateral Alexander radiographs (including ±20° projection error in all planes) and computed tomography of standardized ACJ injury simulations. We assessed inter- and intrarater reliability, convergent validity, and discriminant validity of the circles measurement and subsequently generated a classification of ACJ injury based on displacement.

RESULTS

Reliability and validity of the circles measurement was excellent throughout. Interrater reliability (ICC [intraclass correlation coefficient] [2,1], 95% CI; n = 78; 4 observers) was 0.976 (0.964-0.985). Intrarater reliability (ICC [2,1]; 95% CI; n = 78; 2 measures) was 0.998 (0.996-0.998). Convergent validity (Pearson correlation coefficient, r) was 0.970 for ideal radiographs and 0.889 with ±20° projection error in all planes. Discriminant validity, with 1-way analysis of variance, showed a P value of <.0001 and effect size (η²) of 0.960, with the ability to distinguish between the previously defined stable (Rockwood IIIA) and unstable (Rockwood IIIB) injuries. The results permitted objective, statistically sound parameters for the proposed ABC classification system.

CONCLUSION

The circles measurement is a simple, reliable, valid, accurate, and resilient parameter for assessing ACJ displacement and can be used in conjunction with the proposed ABC classification to define ACJ injuries more accurately and objectively than previously described.

CLINICAL RELEVANCE

This novel parameter has the potential to standardize the initial assessment and possibly the subsequent clinical management of ACJ injuries, in addition to providing a standardized measure for future research.

Editorial Commentary: No Difference in Knotted Versus Knotless Anchors for Labral Repair in the Shoulder

In comparing knotted versus knotless anchors for labral repair in the shoulder, there are no significant differences in clinical outcomes or biomechanical properties including load to failure.

BiPOD arthroscopically assisted bidirectional stabilisation technique for high-grade acromioclavicular joint injury: two-year clinical and radiological outcomes

PURPOSE

The purpose of this study was to evaluate the intermediate-term clinical and radiological outcomes for acute, unstable acromioclavicular joint (ACJ) injuries treated with the arthroscopically assisted BiPOD stabilisation technique.

METHODS

Twenty-three patients who sustained acute, unstable ACJ injuries were included in this prospective study. We recorded demographics, injury classification, time to surgery, clinical scores, radiological outcomes and complications; each patient completed a minimum of 2 years post-operative observation.

RESULTS

Mean follow-up was 26 months (range, 24-34). Clinical outcomes scores demonstrated good 2-year results: relative Constant score, 97.9/100; ACJ Index, 89.4/100; Subjective Shoulder Value, 92.4/100 and Taft = 11.1/12. Final C-C distance showed a mean of 0.7 mm (SD ± 1.8 mm) at 2 years. Complication rate was 9%.

CONCLUSION

The BiPOD technique shows excellent, reliable intermediate-term results with a favourable complication rate compared to existing techniques; it provides a comprehensive surgical option for the stabilisation of acute ACJ injuries restoring both vertical and horizontal stability.

Ulnar footprints of the distal radioulnar ligaments: a detailed topographical study in 21 cadaveric wrists

Understanding of the exact topography of the distal radioulnar ligaments insertions remains limited. An anatomical study was performed in 21 fresh frozen cadaveric wrists, where the superficial and deep ligaments were sequentially transected sharply at their ulnar insertions. The relationships between the distal radioulnar ligament footprints relative to the bony landmarks of the ulnar styloid were digitized. Our study demonstrated that in the coronal plane, the superficial distal radioulnar ligaments inserted at an average of 87% of the styloid height proximally to the styloid tip distally. The deep distal radioulnar ligaments inserted at an average of 81% of the styloid height distally to the fovea proximally. The superficial footprint had an area of 10.6 mm² on the ulnar styloid. The deep distal radioulnar ligaments attachment was asymmetric and generally had two separate footprints. This study adds important topographical knowledge about the footprint of the distal radioulnar ligaments and may contribute to understanding the consequences of ulnar styloid fractures and distal radioulnar ligaments lesions.

Improved identification of unstable acromioclavicular joint injuries in a clinical population using the acromial center line to dorsal clavicle radiographic measurement

BACKGROUND

Accurate classification and subsequent management of acromioclavicular (AC) joint injuries remains a contentious topic. The updated Rockwood classification acknowledges "stable IIIA" and "unstable IIIB" injuries, a watershed accepted by ISAKOS and important in guiding clinical management. Traditionally, the coracoclavicular distance is used to classify these injuries, despite well-documented limitations. This study aimed to evaluate displacement in AC joint injuries by measuring both coracoclavicular (CC) distance and the newly proposed acromial center line to dorsal clavicle (AC-DC) distance, in a cohort of patients, and correlate the results between the 2 measurements and relationship to Rockwood grade.

MATERIALS AND METHODS

Ninety consecutive cases of AC joint injury were evaluated radiographically for Rockwood classification, CC distance on anteroposterior radiographs, and AC-DC distance on Alexander view radiographs. Inter- and intraobserver reliability for each measurement was calculated as well as correlation between the 2 measurement types and the degree to which each measurement accurately represented the Rockwood classification.

RESULTS

Although both CC and AC-DC measurements showed very high inter- and intraobserver reliability, the CC distance systematically underestimated the degree of AC joint displacement when compared with the AC-DC measurement as the severity of injury increased, particularly in the presence of posterior horizontal displacement such as that seen in Rockwood IV injuries.

CONCLUSION

The AC-DC measurement and use of the Alexander view provides the clinician with a more realistic appreciation of true AC joint displacement, especially in defining watershed cases (ie, IIIA/IIB/IV) and may better inform the decision-making process regarding management options and recommendations.

Surgical Management of Massive Irreparable Cuff Tears: Latissimus Dorsi Transfer for Posterosuperior Tears

PURPOSE OF REVIEW

This review aims to describe the role of the latissimus dorsi transfer (LDT) for patients with irreparable posterosuperior rotator cuff tears (RCTs).

RECENT FINDINGS

Historically, the LDT has been performed as an open (double-incision) procedure for neurologically intact, relatively young patients with irreparable posterosuperior RCTs with disabling loss of active external rotation with or without impaired active elevation. The transferred tendon reconstitutes the posterior rotator cuff and force couple, respectively and thus has the potential to function effectively as an external rotator and humeral head depressor. Long-term results of the open technique have demonstrated in the majority of patients substantial and durable improvements in shoulder function and pain relief at the 10-year benchmark. With the advancements of arthroscopic surgery, the LDT was expanded to an arthroscopically assisted procedure with promising short-term results. In addition to adequate technical performance, the success of the procedure depends on preoperative factors, such as exclusion of glenohumeral osteoarthritis and acromial acetabularization; intact or reparable subscapularis tendon; intact (or hypertrophic) teres minor muscle; adequate preoperative activity of the latissimus dorsi; and normal or mild impairment of overhead function. The LDT (open or arthroscopically assisted) is a reliable treatment option for patients with massive, irreparable posterosuperior RCTs with disabling loss of active external rotation, with or without diminished overhead function and without advanced glenohumeral osteoarthritis. Precise patient selection is of tremendous importance in the success of the LDT.

Biomechanical comparison of two biplanar and one monoplanar reconstruction techniques of the acromioclavicular joint

INTRODUCTION

The purpose of this proof-of-concept study was to investigate the biomechanical performance of two surgical techniques, namely (1) the double Tight-Rope fixation with an additional acromioclavicular FiberTape fixation (DTRC) and (2) the fixation of the clavicle to the acromion and coracoid in a bipodal manner (Bipod) using a Poly-Tape and FiberTape. Both techniques intend to address vertical and horizontal instability after acromioclavicular dislocation. They were compared with the commonly used (3) double Tight-Rope (DTR) technique, which only stabilizes the clavicle to the coracoid.

MATERIALS AND METHODS

The acromioclavicular joint (ACJ) of 18 composite Sawbone shoulder specimens (6 per reconstruction group) were tested for posterosuperior elongation (70N cyclical load, 1500 cycles), load-to-failure and stiffness.

RESULTS

After 1500 cycles, the DTRC, Bipod and DTR group showed an elongation of 0.45 mm (SD 0.14 mm), 1.19 mm (SD 0.54 mm), and 0.46 mm (SD 0.15 mm), respectively. Although the elongation of the Bipod group was increased when compared to the other two groups (Bipod versus DTRC p = 0.008; Bipod versus DTR p = 0.006), the difference was less than 0.7 mm. The DTRC showed a higher load-to-failure of 656.1N (SD 58.1 N) compared to the Bipod [531.1 N (SD 108.2N) (p = 0.039)] and DTR group [522.8 N (SD 32.8 N) (p = 0.033)].

CONCLUSION

The DTRC and the DTR group resulted in similar low elongation, while the elongation in the Bipod technique was slightly higher. Even though this difference of 0.7 mm shows statistical significance, it most likely has no clinical relevance. When testing in posterosuperior direction, which is the clinically relevant load vector, an additional fixation of the clavicle to the acromion did not reduce elongation in this study. It is, furthermore, questionable if the benefit of an increased load-to-failure in combination with no improvement in elongation and stiffness as seen in the DTRC group outweighs the possible risks and increased costs coming with the DTRC refixation.

Subscapularis in Reverse Total Shoulder Arthroplasty

The use of reverse total shoulder arthroplasty (RSA) is becoming increasingly popular, but many biomechanical aspects are poorly understood. Particularly, the role and function of the subscapularis following RSA are unclear. Several clinical and biomechanical studies have analyzed its role in range of motion and stability. There is some evidence that the subscapularis is beneficial for stability but may reduce range of motion. This review provides an overview of the current literature, which suggests that the subscapularis may have a more important role in RSA than originally thought.

Genetic lineage tracing of targeted cell populations during enthesis healing

Rotator cuff supraspinatus tendon injuries are clinically challenging due to the high rates of failure after surgical repair. One key limitation to functional healing is the failure to regenerate the enthesis transition between tendon and bone, which heals by disorganized scar formation. Using two models of supraspinatus tendon injury in mouse (partial tear and full detachment/repair), the purpose of the study was to determine functional gait outcomes and identify the origin of the cells that mediate healing. Consistent with previous reports, enthesis injuries did not regenerate; partial tear resulted in a localized scar defect adjacent to intact enthesis, while full detachment with repair resulted in full disruption of enthesis alignment and massive scar formation between tendon and enthesis fibrocartilage. Although gait after partial tear injury was largely normal, gait was permanently impaired after full detachment/repair. Genetic lineage tracing of intrinsic tendon and cartilage/fibrocartilage cells (Scx^CreERT2 and Sox9^CreERT2 , respectively), myofibroblasts (αSMA^CreERT2 ), and Wnt-responsive stem cells (Axin2^CreERT2 ) failed to identify scar-forming cells in partial tear injury. Unmineralized enthesis fibrocartilage was strongly labeled by Sox9^CreERT2 while Axin2^CrERT2 labeled a subset of tendon cells away from the skeletal insertion site. In contrast to the partial tear model, Axin2^CreERT2 labeling showed considerable contribution of Axin2^lin cells to the scar after full detachment/repair. Clinical Significance: Clinically relevant models of rotator cuff tendon injuries in mouse enable the use of genetic tools; lineage tracing suggests that distinct mechanisms of healing are activated with full detachment/repair injuries versus partial tear. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3275-3284, 2018.

Current concepts in the primary management of irreparable posterosuperior rotator cuff tears without arthritis

Various procedures exist for patients with irreparable posterosuperior rotator cuff tears (IRCT). At present, no single surgical option has demonstrated clinical superiority.There is no panacea for treatment and patients must be aware, in cases of palliative or non-prosthetic options, of an alarming rate of structural failure (around 50%) in the short term.The current review does not support the initial use of complex and expensive techniques in the management of posterosuperior IRCT.Further prospective and comparative studies with large cohort populations and long-term follow-up are necessary to establish effectiveness of expensive or complicated procedures such as superior capsular reconstruction (SCR), subacromial spacers or biological augmentation as reliable and useful alternative treatments for IRCT. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.180002.

Many Shoulder MRI Findings in Elite Professional Throwing Athletes Resolve After Retirement: A Clinical and Radiographic Study

BACKGROUND

Anatomic findings on MRI scans of the shoulder likely affect patients differently based on their physical demands and fitness levels. The natural history of these anatomic findings once professional overhead athletes retire remains unclear. A better understanding of what happens with these findings after retirement may influence how we manage shoulder problems in athletes.

PURPOSE

(1) What is the natural history of MRI-observed findings in the throwing and nonthrowing shoulders of professional European handball players after retirement from the sport? What proportion of these individuals have diagnosable findings on MRI, and do these findings disappear after retirement? (2) Do clinical findings such as Constant and Murley score and shoulder ROM change after retirement in these professional overhead athletes?

METHODS

The inception cohort of this series consisted of the entire Swiss National European handball team except the goalkeepers. These 30 professional players also played in the highest Swiss handball league in 2001. None of these players previously had shoulder surgery. During their career, they had a clinical assessment and bilateral shoulder MRI as part of an earlier study. We sought to evaluate the players who had retired and did not have a history of shoulder surgery, to evaluate the natural history of MRI-observed findings made in the initial study during their professional career. Of the 30 players, 10 were excluded (four continued to play professionally, four declined participation, and two had surgery after the initial study), leaving 20 (66%) for analysis at a mean of 6 years (SD, 3 years) after retirement. To gain a better understanding of the evolution of these MRI findings in the longer-term, we also evaluated 18 additional former professional European handball players who did not have any history of shoulder surgery, had all played in the highest Swiss league and for the National Team, and had terminated their career at a mean of 15 years (SD, 3 years) ago. All the subjects in both study groups (those at 6 and 15 years after retirement) underwent a detailed interview, standardized clinical examination including ROM measurements, collection of the Constant and Murley scores and the subjective shoulder value of both shoulders, and bilateral shoulder MRI. MRI findings (consisting of abnormalities and normal variations) were reported as radiographic diagnoses, independent of the potential that these findings could be considered normal variations in people in this age group.

RESULTS

At the initial MRI evaluation, the proportion of active professional European handballers with diagnosable MRI findings in the throwing shoulder was 19 of 20 (95%) and for the handballers with nonthrowing shoulders was 17 of 20 (85%), while 15 years after retirement, both shoulders of all subjects showed MRI findings. None of the rotator cuff tears progressed to full-thickness tears after retirement. In the throwing shoulders, we observed fewer individuals with ganglion cysts larger than 5 mm (initial followup: six of 20 [30%] versus 6 years after retirement: 0 of 20 (0%); odds ratio, 14.5; [95% CI, 0.7-283]; p = 0.044). The Constant and Murley score increased in the throwing shoulder from 93 points (SD, 6 points) at initial followup to 98 points (SD, 3 points) at a mean of 6 years after retirement (mean difference, 5 points; SD, 5 points; 95% CI, 2.5-7.4; p < 0.001), and to 97 points (SD, 3 points) at a mean of 15 years after retirement. However these differences are below the typically reported minimum clinically important difference for the Constant and Murley score, and so are unlikely to be clinically relevant. External rotation in 90° abduction remained increased in the throwing shoulder compared with the nonthrowing shoulder up to 15 years after retirement (initial followup: mean difference, 8°; p = 0.014; 15 years after retirement: mean difference, 4°; SD, 15; p = 0.026). Internal rotation remained decreased in the throwing compared with the nonthrowing shoulders (during the career: mean difference, 5° [SD, 10°], p = 0.036; 15 years after retirement: mean difference, 3° [SD, 4°], p = 0.021).

CONCLUSIONS

Our data suggest that findings of the throwing shoulder like partial rotator cuff tears, bony cysts and ganglions do not progress after retirement, and sometimes they resolve. Because of this and because many MRI changes correlate poorly with clinical symptoms, the indication for surgical treatment of these findings should be questioned very carefully.

LEVEL OF EVIDENCE

Level II, prognostic study.

[Current aspects and new techniques in dislocation of the shoulder joint]

With 12% of all injuries concerning the shoulder, acromioclavicular (AC) joint dislocations are a common injury especially in young and active patients. The Rockwood classification is widely accepted, which differentiates between six types depending on the degree of injury and the vertical dislocation. Because the classification does not adequately address the horizontal instability, its benefits are questionable and there is currently no consensus. For this reason, the classification and the therapy of these injuries are increasingly becoming the subject of scientific investigations. Whereas conservative treatment for type I and II injuries and operative treatment for type IV-VI injuries are widely accepted, there is still no agreement in treating type III lesions. The goal of this review article is to present the current evidence for the diagnostics, different classifications and therapeutic possibilities.

New quantitative radiographic parameters for vertical and horizontal instability in acromioclavicular joint dislocations

PURPOSE

The aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs.

METHODS

A Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior-posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements.

RESULTS

All radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC-DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC-PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC-DC and GC-PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC-DC in 20° anteverted malpositioning and for GC-PC in 20° retroverted malpositioning.

CONCLUSIONS

AC-DC and the GC-PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC-DC for assessing vertical displacement and GC-PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries.

Triceps-sparing extra-articular step-cut olecranon osteotomy for distal humeral fractures: an anatomic study

BACKGROUND

This anatomic study investigated the distal humeral articular surface exposure achievable through a triceps-sparing oblique extra-articular osteotomy of the olecranon with a step-cut modification compared with the anconeus flap transolecranon apex distal chevron osteotomy. In addition, the bone contact surface areas of the osteotomized surfaces after transolecranon and extra-articular osteotomies were compared.

METHODS

Seven pairs of fresh adult cadaveric elbow joints were examined. Each of the right elbows underwent triceps-sparing extra-articular step-cut olecranon osteotomy (SCOOT) with an anconeus flap, and the left elbows underwent the anconeus flap transolecranon apex distal chevron osteotomies (CO). The articular surface exposed by each of the osteotomy techniques was then digitally analyzed using a 3-dimensional measurement system. The bone contact surface area of the osteotomized surfaces was also assessed.

RESULTS

The percentage of total joint exposed by the SCOOT group was less than the CO group (SCOOT: 64% ± 3% vs. CO: 73% ± 3%; P = .002). There was significantly greater bone contact surface area of the osteotomized surfaces in the SCOOT group compared with the CO group (SCOOT: 1172 ± 251 mm² vs. CO: 457 ± 133 mm²; P = .002).

CONCLUSION

The triceps SCOOT procedure with an anconeus flap provides excellent distal humeral articular surface exposure with the added benefit of a substantially increased (2.6-times) bone contact surface area of the osteotomized surfaces.

Neer Award 2016: reduced muscle degeneration and decreased fatty infiltration after rotator cuff tear in a poly(ADP-ribose) polymerase 1 (PARP-1) knock-out mouse model

BACKGROUND

Disturbed muscular architecture, atrophy, and fatty infiltration remain irreversible in chronic rotator cuff tears even after repair. Poly (adenosine 5'-diphosphate-ribose) polymerase 1 (PARP-1) is a key regulator of inflammation, apoptosis, muscle atrophy, muscle regeneration, and adipocyte development. We hypothesized that the absence of PARP-1 would lead to a reduction in damage to the muscle subsequent to combined tenotomy and neurectomy in a PARP-1 knockout (KO) mouse model.

METHODS

PARP-1 KO and wild-type C57BL/6 (WT group) mice were analyzed at 1, 6, and 12 weeks (total n = 84). In all mice, the supraspinatus and infraspinatus muscles of the left shoulder were detached and denervated. Macroscopic analysis, magnetic resonance imaging, gene expression analysis, immunohistochemistry, and histology were used to assess the differences in PARP-1 KO and WT mice.

RESULTS

The muscles in the PARP-1 KO group had significantly less retraction, atrophy, and fatty infiltration after 12 weeks than in the WT group. Gene expression of inflammatory, apoptotic, adipogenic, and muscular atrophy genes was significantly decreased in PARP-1 KO mice in the first 6 weeks.

DISCUSSION

Absence of PARP-1 leads to a reduction in muscular architectural damage, early inflammation, apoptosis, atrophy, and fatty infiltration after combined tenotomy and neurectomy of the rotator cuff muscle. Although the macroscopic reaction to injury is similar in the first 6 weeks, the ability of the muscles to regenerate was much greater in the PARP-1 KO group, leading to a near-normalization of the muscle after 12 weeks.

BiPOD Arthroscopic Acromioclavicular Repair Restores Bidirectional Stability

Stabilizing the acromioclavicular joint in the vertical and horizontal planes is challenging, and most current techniques do not reliably achieve this goal. The BiPOD repair is an arthroscopically assisted procedure performed with image intensifier guidance that reconstructs the coracoclavicular ligaments as well as the acromioclavicular ligaments to achieve bidirectional stability. Repair is achieved with a combination of 2-mm FiberTape (Arthrex, Naples, Florida) and 20-mm Poly-Tape (Neoligaments, Leeds, England) to achieve rigid repair, prevent bone abrasion, and promote tissue ingrowth. This study is a prospective review of the first 6 patients treated for high-grade acute acromioclavicular injury with the BiPOD technique. The study included 6 men who were 21 to 36 years old (mean, 27 years). At 6-month follow-up, complications were recorded and radiographic analysis was used to determine the coracoclavicular distance for vertical reduction and the amount of acromioclavicular translation on the Alexander axillary view was used to determine horizontal reduction. One patient had a superficial infection over the tape knot. The difference in coracoclavicular distance between the operated side and the uninvolved side was 9±2 mm preoperatively and 0.3±2 mm at 6-month follow-up. On Alexander axillary view, all 6 patients showed stable reduction, which is defined as a clavicle that is in line with the acromion. The findings show that BiPOD acromioclavicular reconstruction restores bidirectional stability of the acromioclavicular joint at 6 months. [Orthopedics. 2017; 40(1):e35-e43.].

Optimal Lateral Row Anchor Positioning in Posterior-Superior Transosseous Equivalent Rotator Cuff Repair: A Micro-Computed Tomography Study

Background:

The optimal placement of suture anchors in transosseous-equivalent (TOE) double-row rotator cuff repair remains controversial.

Purpose:

A 3-dimensional (3D) high-resolution micro–computed tomography (micro-CT) histomorphometric analysis of cadaveric proximal humeral greater tuberosities (GTs) was performed to guide optimal positioning of lateral row anchors in posterior-superior (infraspinatus and supraspinatus) TOE rotator cuff repair.

Study Design:

Descriptive laboratory study.

Methods:

Thirteen fresh-frozen human cadaveric proximal humeri underwent micro-CT analysis. The histomorphometric parameters analyzed in the standardized volumes of interest included cortical thickness, bone volume, and trabecular properties.

Results:

Analysis of the cortical thickness of the lateral rows demonstrated that the entire inferior-most lateral row, 15 to 21 mm from the summit of the GT, had the thickest cortical bone (mean, 0.79 mm; P = .0001), with the anterior-most part of the GT, 15 to 21 mm below its summit, having the greatest cortical thickness of 1.02 mm (P = .008). There was a significantly greater bone volume (BV; posterior, 74.5 ± 27.4 mm³; middle, 55.8 ± 24.9 mm³; anterior, 56.9 ± 20.7 mm³; P = .001) and BV as a percentage of total tissue volume (BV/TV; posterior, 7.3% ± 2.7%, middle, 5.5% ± 2.4%; anterior, 5.6% ± 2.0%; P = .001) in the posterior third of the GT than in intermediate or anterior thirds. In terms of both BV and BV/TV, the juxta-articular medial row had the greatest value (BV, 87.3 ± 25.1 mm³; BV/TV, 8.6% ± 2.5%; P = .0001 for both) followed by the inferior-most lateral row 15 to 21 mm from the summit of the GT (BV, 62.0 ± 22.7 mm³; BV/TV, 6.1% ± 2.2%; P = .0001 for both). The juxta-articular medial row had the greatest value for both trabecular number (0.3 ± 0.06 mm^–1; P = .0001) and thickness (0.3 ± 0.08 μm; P = .0001) with the lowest degree of trabecular separation (1.3 ± 0.4 μm; P = .0001). The structure model index (SMI) has been shown to strongly correlate with bone strength, and this was greatest at the inferior-most lateral row 15 to 21 mm from the summit of the GT (2.9 ± 0.9; P = .0001).

Conclusion:

The inferior-most lateral row, 15 to 21 mm from the tip of the GT, has good bone stock, the greatest cortical thickness, and the best SMI for lateral row anchor placement. The anterior-most part of the GT 15 to 21 mm below its summit had the greatest cortical thickness of all zones. The posterior third of the GT also has good bone stock parameters, second only to the medial row. The best site for lateral row cortical anchor placement is 15 to 21 mm below the summit of the GT.

Clinical Relevance:

Optimal lateral anchor positioning is 15 to 21 mm below the summit of the greater tuberosity in TOE.

Inclination-dependent changes of the critical shoulder angle significantly influence superior glenohumeral joint stability

BACKGROUND

The critical shoulder angle combines the acromion index and glenoid inclination and has potential to discriminate between shoulders at risk for rotator cuff tear or osteoarthritis and those that are asymptomatic. However, its biomechanics, and particularly the role of the glenoid inclination, are not yet fully understood.

METHODS

A shoulder simulator was used to analyze the independent influence of glenoid inclination during abduction from 0 to 60°. Spindle motors transferred tension forces by a cable-pulley on human cadaveric humeri. A six-degree-of-freedom force transducer was mounted directly behind the polyethylene glenoid to measure shear and compressive joint reaction force and calculate the instability ratio (ratio of shear and compressive joint reaction force) with the different force ratios of the deltoid and supraspinatus muscles (2:1 and 1:1). A stepwise change in the inclination by 5° increments allowed simulation of a critical shoulder angle range of 20° to 45°.

FINDINGS

Tilting the glenoid to cranial (increasing the critical shoulder angle) increases the shear joint reaction force and therefore the instability ratio. A balanced force ratio (1:1) between the deltoid and the supraspinatus allowed larger critical shoulder angles before cranial subluxation occurred than did the deltoid-dominant ratio (2:1).

INTERPRETATION

Glenoid inclination-dependent changes of the critical shoulder angle have a significant impact on superior glenohumeral joint stability. The increased compensatory activity of the rotator cuff to keep the humeral head centered may lead to mechanical overload and could explain the clinically observed association between large angles and degenerative rotator cuff tears.

SECEC Research Grant 2008 II: Use of platelet- and leucocyte-rich fibrin (L-PRF) does not affect late rotator cuff tendon healing: a prospective randomized controlled study

BACKGROUND

Because the retear rate after rotator cuff repairs remains high, methods to improve healing are very much needed. Platelet-rich concentrates have been shown to enhance tenocyte proliferation and promote extracellular matrix synthesis in vitro; however, their clinical benefit remains unclear. We hypothesized that arthroscopic rotator cuff repair with leucocyte- and platelet-rich fibrin (L-PRF) results in better clinical and radiographic outcome at 12 months of follow-up than without L-PRF.

METHODS

Thirty-five patients were randomized to receive arthroscopic rotator cuff repair with L-PRF locally applied to the repair site (L-PRF+ group, n = 17) or without L-PRF (L-PRF- group, n = 18). Preoperative and postoperative clinical evaluation included the Subjective Shoulder Value, visual analog score for pain, Simple Shoulder Test, and Constant-Murley score. The anatomic watertight healing, tendon thickness, and tendon quality was evaluated using magnetic resonance arthrography at 12 months of follow-up.

RESULTS

No complications were reported in either group. The mean Subjective Shoulder Value, Simple Shoulder Test, and Constant-Murley scores increased from preoperatively to postoperatively, showing no significant differences between the groups. Complete anatomic watertight healing was found in 11 of 17 in the L-PRF+ group and in 11 of 18 in the L-PRP- group (P = .73). The mean postoperative defect size (214 ± 130 mm(2) in the L-PRF+ group vs 161 ± 149 mm(2) in the L-PRF- group; P = .391) and the mean postoperative tendon quality according to Sugaya (L-PRF+ group: 3.0 ± 1.4, L-PRF- group: 3.0 ± 0.9) were similar in both groups at 12 months of follow-up.

CONCLUSION

Arthroscopic rotator cuff repair with application of L-PRF yields no beneficial effect in clinical outcome, anatomic healing rate, mean postoperative defect size, and tendon quality at 12 months of follow-up.

Extra-articular step osteotomy of the olecranon: A biomechanical assessment

BACKGROUND

Trans-olecranon chevron osteotomies (COs) remain the gold standard surgical approach to type C fractures of the distal humerus. This technique is associated with a high complication rate and development of an extra-articular olecranon osteotomy may be advantageous. The aim of this study was to compare the load to failure of COs with extra-articular oblique osteotomies (OOs) as well as modified, extra-articular step osteotomies (SOs).

METHODS

These three osteotomies and their subsequent fixation utilizing a standardized tension band wiring technique were tested in 42 composite analog ulnae models at 20° and 70° of flexion. Triceps loading was simulated with a servo hydraulic testing machine. All specimens were isometrically loaded until failure. Kinematic and force data, as well as interfragmentary motion were recorded.

RESULTS

At 70°, CO failed at a mean load of 963 N (SD 104 N), the OO at 1512 N (SD 208 N) and the SO at 1484 N (SD 153 N), (P<0.001). At 20°, CO failed at a mean load of 707 N (SD 104 N) and OO at 1009 N (SD 85 N) (P=0.006). The highest load to failure was observed for the SO, which was 1277 N (SD 172 N). The load to failure of the SO was significantly higher than the CO as well as the OO.

CONCLUSION

Extra-articular osteotomies showed a significantly higher load to failure in comparison to traditional CO. At near full extension (20° of flexion), this biomechanical advantage was further enhanced by a step-cut modification of the extra-articular oblique osteotomy.

[Unnecessary operations in shoulder surgery: "table of confusion" applied to "field of confusion"]

Attributing a surgical procedure as unnecessary or necessary is a binomial classifier that can be analysed in a so called "table of confusion". Ambroise Parré (1510 - 1590) observed that wound treatment with hot oil was harming instead of healing, and concluded that it should be discarded as "standard of care". Still today, the answer to the same question "What is the standard of care?" is decisive when an operation needs to be classified as "necessary" or "unnecessary". Patients' expectations can also influence the decision making process between surgical and conservative treatment options. Fracture of the humeral head is an example how two different surgical strategies (primary versus secondary joint replacement) can lead to "unnecessary" operation. However, it is only retrospectively that an operation appears unnecessary. Further factors that could be analysed are the delay between decision and operation (so called "test of time") and financial aspects. In conclusion, it is only objective and scientific analysis that can lead to viable standards of care for our practice. This is the only way to protect patients as well as surgeons from unnecessary operations.

Biologics in rotator cuff surgery

Pathologies of the rotator cuff are by far the most common cause of shoulder dysfunction and pain. Even though reconstruction of the rotator cuff results in improved clinical outcome scores, including decreased pain, several studies report high failure rates. Orthopaedic research has therefore focused on biologically augmenting the rotator cuff reconstruction and improving tendon-bone healing of the rotator cuff. This biological augmentation has included the application of different platelet concentrates containing growth factors, mesenchymal stem cells, scaffolds and a combination of the above. The present review provides an overview over the biological augmentation options based upon current evidence.

Age, trauma and the critical shoulder angle accurately predict supraspinatus tendon tears

BACKGROUND

The pathogenesis of full-thickness tears of the rotator cuff remains unclear. Apart from age and trauma, distinct scapular morphologies have been found to be associated with rotator cuff disease. The purpose of the present study was to evaluate whether a score formed using these established risk factors was able to predict the presence of a rotator cuff tear reliably.

METHODS

We retrospectively assessed a consecutive series of patients with a minimal age of 40 years old, who had true antero-posterior (AP) radiographs of their shoulders, as well as a magnetic resonance (MR) gadolinium-arthrography, between January and December 2011. In all of these patients, the critical shoulder angle (CSA) was determined, and MR images were assessed for the presence of rotator cuff tears. Additionally, the patients' charts were reviewed to obtain details of symptom onset. Based on these factors, the so-called rotator cuff tear (RCT) score was calculated.

RESULTS

Patients with full-thickness RCTs were significantly older and had significantly larger CSAs than patients with intact rotator cuffs. Multiple logistic regression, using trauma, age and CSA as independent variables, revealed areas under the curve (AUCs) for trauma of 0.55, for age of 0.65 and for CSA of 0.86. The combination of all three factors was the most powerful predictor, with an AUC of 0.92.

CONCLUSION

Age, trauma and the CSA can accurately predict the presence of a posterosuperior RCT.

LEVEL OF EVIDENCE

Level IV. Case series with no comparison groups.

Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives

Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

ACL reconstruction with physiological graft tension by intraoperative adjustment of the anteroposterior translation to the uninjured contralateral knee

PURPOSE

Fixation of anterior cruciate ligament (ACL) substitutes with non-physiological anteroposterior translation (APT) worsens outcome. The aim was to present a technique for physiological APT adjustment of the transplant in ACL reconstruction and its outcome at midterm.

METHODS

In a consecutive series of 28 patients (age 32 ± 11 years, 24 male), chronic ACL deficiency was treated by bone-patella-tendon-bone reconstruction. Transplant APT was adjusted to that of the contralateral uninjured ACL, measured 3, 6, and 12 months postoperatively using the Rolimeter. At a median follow-up of 5.3 years (3-8 years), 82% of the patients were re-evaluated with APT measurement and using IKDC-, Tegner-, Lysholm-Scores, conventional radiographs and MRI.

RESULTS

No differences in APT (mean ± SD) between uninjured and reconstructed knees were observed after adjustment (6 ± 1 versus 6 ± 1 mm, n.s.). Three months postoperatively, a statistically significant increase in APT (7 ± 1 mm) and a further increase at midterm (9 ± 2 mm) were observed. Patients scored "normal" or "nearly normal", respectively, in 79% (IKDC) and 4 (3-9) points (Tegner; median, range) or 89 ± 9 points (Lysholm; mean ± SD). Radiological evaluation showed no, minimal or moderate joint degeneration in 5, 20 and 75% of patients, respectively. MRI confirmed intact ACL transplants in all patients.

CONCLUSION

ACL reconstruction using the presented technique was considered successful, as patients did not suffer from subjective instability, radiographic analysis did not provide evidence for graft rupture at midterm. However, APT increase and occurrence of degenerative changes in reconstructed knees at the midterm might not be prevented even by restoration of a physiological APT in ACL reconstruction. The Rolimeter can be used for quick and easy intraoperative indirect control of the applied tension to the ACL transplant by measuring the APT to obtain physiological tensioning resulting in a satisfying outcome at midterm.

LEVEL OF EVIDENCE

IV.

Arthroscopic Hill-Sachs Remplissage with Bankart Repair: Strategy and Technique

Introduction

Arthroscopic Hill-Sachs remplissage describes the fixation of the posterior aspect of the capsule and the infraspinatus tendon into a posterosuperior humeral head impaction fracture in cases of recurrent anteroinferior glenohumeral instability.

Step 1 Anterior Capsulolabral Mobilization and Glenoid Preparation

Perform diagnostic arthroscopy through a standard posterior portal to rule out additional pathology and document the "engaging" nature of the Hill-Sachs defect.

Step 2 Preparation of the Hill-Sachs Defect

With the camera remaining in the posterior portal, the assistant provides visualization of the Hill-Sachs defect by translating the humeral head anteriorly over the glenoid rim with direct pressure on the proximal part of the humerus.

Step 3 Remplissage with the Posterior Aspect of the Capsule and Infraspinatus Tendon

Transfer the camera to the anterior portal and leave a switching stick in the posterior portal; under direct visualization, withdraw the posterolateral cannula from the posterior aspect of the capsule and the infraspinatus tendon until it rests in the subdeltoid space (∼1 cm).

Step 4 Anterior Bankart Repair

Transition the camera back to the standard posterior portal over a switching stick in order to perform the Bankart repair.

Step 5 Postoperative Rehabilitation Protocol

Patients wear a brace and perform pendulum exercises for four weeks, and then initiate range-of-motion exercises; they avoid strengthening for eight weeks and sports for three to six months.

Results

In our recently published series of forty-seven patients (forty-two male and five female; average age, twenty-nine years), the use of Bankart repair combined with Hill-Sachs remplissage performed according to the above algorithm resulted in 98% of the patients being satisfied or very satisfied with their surgical result and a recurrent instability rate of only 2% at a mean of twenty-four months postoperatively.IndicationsContraindicationsPitfalls & Challenges.

Increased vascularization during early healing after biologic augmentation in repair of chronic rotator cuff tears using autologous leukocyte- and platelet-rich fibrin (L-PRF): a prospective randomized controlled pilot trial

HYPOTHESIS

We hypothesized that arthroscopic rotator cuff repairs using leukocyte- and platelet-rich fibrin (L-PRF) in a standardized, modified protocol is technically feasible and results in a higher vascularization response and watertight healing rate during early healing.

METHODS

Twenty patients with chronic rotator cuff tears were randomly assigned to 2 treatment groups. In the test group (N = 10), L-PRF was added in between the tendon and the bone during arthroscopic rotator cuff repair. The second group served as control (N = 10). They received the same arthroscopic treatment without the use of L-PRF. We used a double-row tension band technique. Clinical examinations including subjective shoulder value, visual analog scale, Constant, and Simple Shoulder Test scores and measurement of the vascularization with power Doppler ultrasonography were made at 6 and 12 weeks.

RESULTS

There have been no postoperative complications. At 6 and 12 weeks, there was no significant difference in the clinical scores between the test and the control groups. The mean vascularization index of the surgical tendon-to-bone insertions was always significantly higher in the L-PRF group than in the contralateral healthy shoulders at 6 and 12 weeks (P = .0001). Whereas the L-PRF group showed a higher vascularization compared with the control group at 6 weeks (P = .001), there was no difference after 12 weeks of follow-up (P = .889). Watertight healing was obtained in 89% of the repaired cuffs.

DISCUSSION/CONCLUSIONS

Arthroscopic rotator cuff repair with the application of L-PRF is technically feasible and yields higher early vascularization. Increased vascularization may potentially predispose to an increased and earlier cellular response and an increased healing rate.

Ligament origins are preserved in distal radial intraarticular two-part fractures: a computed tomography-based study

Background Operative fixation of intraarticular distal radius fractures is increasingly common. A greater understanding of fracture patterns will aid surgical fixation strategy. Previous studies have suggested that ligamentous insertions may less commonly be involved, but these have included heterogeneous groups of fractures and have not addressed Lister's tubercle. Purpose We hypothesize that fracture lines of distal radial intraarticular 2-part fractures have reproducible patterns. They propagate through the cortical bone between ligament origins and do not involve Lister's tubercle. Methods Axial CT scans of two-part intraarticular distal radius fractures were assessed independently by two examiners. The fractures were mapped onto a grid and the cortical breaches expressed as a percentile of the total radial width or length. The cortical breaches were compared with the ligamentous insertions on the distal and Lister's tubercle. Associated injuries were also documented. Results The cortical breaches occurred between the ligamentous insertions in 85%. Lister's tubercle was not involved in 95% of the fractures. Three major fracture patterns emerged: radial styloid, dorsal, and volar. Each major pattern had two subtypes. Associated injuries were common. Scapholunate dissociation was associated with all types, not just the radial styloid fracture pattern. Conclusions The fracture patterns of two-part intraarticular fractures mostly involved the interligamentous zones. Three major groups were identified: dorsal, volar, and radial styloid. Lister's tubercle was preserved with fractures tending to propagate radial or ulnar to this structure. We suggest conceptualizing fracture fragments as osseo-ligamentous units to aid prediction of fracture patterns and associated injury. Study Design Diagnostic III Level of Evidence 3.

Tenocytes of chronic rotator cuff tendon tears can be stimulated by platelet-released growth factors

BACKGROUND

Bone-to-tendon healing after rotator cuff repairs is mainly impaired by poor tissue quality. The tenocytes of chronic rotator cuff tendon tears are not able to synthesize normal fibrocartilaginous extracellular matrix (ECM). We hypothesized that in the presence of platelet-released growth factors (PRGF), tenocytes from chronically retracted rotator cuff tendons proliferate and synthesize the appropriate ECM proteins.

MATERIALS AND METHODS

Tenocytes from 8 patients with chronic rotator cuff tears were cultured for 4 weeks in 2 different media: standard medium (Iscove's Modified Dulbecco's Media + 10% fetal calf serum + 1% nonessential amino acids + 0.5 μg/mL ascorbic acid) and media with an additional 10% PRGF. Cell proliferation was assessed at 7, 14, 21, and 28 days. Messenger (m)RNA levels of collagens I, II, and X, decorin, biglycan, and aggrecan were analyzed using real time reverse-transcription polymerase chain reaction. Immunocytochemistry was also performed.

RESULTS

The proliferation rate of tenocytes was significantly higher at all time points when cultured with PRGF. At 21 days, the mRNA levels for collagens I, II, and X, decorin, aggrecan, and biglycan were significantly higher in the PRGF group. The mRNA data were confirmed at protein level by immunocytochemistry.

CONCLUSIONS

PRGFs enhance tenocyte proliferation in vitro and promote synthesis of ECM to levels similar to those found with insertion of the normal human rotator cuffs.

CLINICAL RELEVANCE

Biologic augmentation of repaired rotator cuffs with PRGF may enhance the properties of the repair tissue. However, further studies are needed to determine if application of PRGF remains safe and effective in long-term clinical studies.

LEVEL OF EVIDENCE

Basic Science Study, Cell Biology.

More accurate component alignment in navigated total knee arthroplasty has no clinical benefit at 5-year follow-up

BACKGROUND AND PURPOSE

Computer navigation in total knee arthroplasty is somewhat controversial. We have previously shown that femoral component positioning is more accurate with computed navigation than with conventional implantation techniques, but the clinical impact of this is unknown. We now report the 5-year outcome of our previously reported 2-year outcome study.

METHODS

78 of initially 84 patients (80 of 86 knees) were clinically and radiographically reassessed 5 (5.1-5.9) years after conventional, image-based, and image-free total knee arthroplasty. The methodology was identical to that used preoperatively and at 2 years, including the Knee Society score (KSS) and the functional score (FS), and AP and true lateral standard radiographs.

RESULTS

Although a more accurate femoral component positioning in the navigated groups was obtained, clinical outcome, number of reoperations, KSS, FS, and range of motion were similar between the groups.

INTERPRETATION

The increased costs and time for navigated techniques did not translate into better functional and subjective medium-term outcome compared to conventional techniques.

[Influence of chronic, structural changes of the muscle-tendon unit on the indication and technique of rotator cuff reconstruction]

Rotator cuff lesions are common and the incidence increases with age. After tendon rupture of the rotator cuff, the muscle-tendon unit retracts, which is accompanied by muscle fatty infiltration, atrophy, and interstitial fibrosis of the musculature, thus, fundamentally changing the muscle architecture. These changes are important prognostic factors for the operative rotator cuff reconstruction outcome. Selection of the correct time point for reconstruction as well as the optimal mechanical fixation technique are decisive for successful attachment at the tendon-to-bone insertion site. Thus, knowledge of the pathophysiological processes plays an important role. The goal of this article is to establish a relationship between currently existing evidence with respect to the preoperatively existing changes of the muscle-tendon unit and the choice of the time for the operation and the operative technique.

Biologically based strategies to augment rotator cuff tears

Lesions of the rotator cuff (RC) are among the most frequent tendon injuries. In spite of the developments in both open and arthroscopic surgery, RC repair still very often fails. In order to reduce the failure rate after surgery, several experimental in vitro and in vivo therapy methods have been developed for biological improvement of the reinsertion. This article provides an overview of the current evidence for augmentation of RC reconstruction with growth factors. Furthermore, potential future therapeutic approaches are discussed. We performed a comprehensive search of the PubMed database using various combinations of the keywords “tendon,” “rotator cuff,” “augmentation,” “growth factor,” “platelet-rich fibrin,” and “platelet-rich plasma” for publications up to 2011. Given the linguistic capabilities of the research team, we considered publications in English, German, French, and Spanish. We excluded literature reviews, case reports, and letters to the editor.