Conjoint Tendon Lengthening Improves Internal Rotation Following Reverse Total Shoulder Arthroplasty: A Cadaveric Study.

INTRODUCTION: Reverse Shoulder Arthroplasty (RSA) is a common procedure for treating a variety of shoulder pathologies. However, many patients struggle with postoperative internal rotation deficits, which often hinder their activities of daily living. The conjoint tendon provides an anatomic barrier that can impede the postoperative internal rotation of the shoulder, and this study aims to evaluate the effect of a conjoint tendon lengthening on the glenohumeral range of motion following RSA. METHODS: This study used ten fresh-frozen cadaver specimens of the upper extremity. An RSA was implanted using a standard deltopectoral approach, and the range of motion was assessed post-implantation. Following this, the conjoint tendon was identified and lengthened using a tendon sheath z-plasty, and the range of motion was re-recorded. Statistical significance for the range of motion gains after conjoint tendon lengthening was determined with a significance level of p < 0.05. RESULTS: Following the lengthening of the conjoint tendon, there were statistically significant improvements in all ranges of motion (p < 0.05). Subjects demonstrated a notable gain in internal rotation to the back by 10.3 cm (p < 0.01), and all ranges of motion increased by at least 10°, except for forward flexion, which increased by 6° (p < 0.001). CONCLUSIONS: This study suggests that lengthening the conjoint tendon improves postoperative range of motion of the glenohumeral joint after RSA, offering a potential solution to a considerable internal rotation deficits that are commonly encountered post-RSA. Subsequent clinical and biomechanical studies should assess the stability of the shoulder joint following conjoint tendon lengthening.

Revision reverse shoulder arthroplasty has similar outcomes to primary reverse shoulder arthroplasty at 5 Year average follow-up.

Background: Shoulder arthroplasty is a successful procedure that provides pain relief and improvements in function and range of motion. Anatomic and reverse shoulder arthroplasty are both effective procedures, and their indications continue to expand. We look at the outcomes of revision reverse total shoulder arthroplasty and compare it to the outcomes of primary reverse and anatomic total shoulder arthroplasty. Methods: We identified patients undergoing total shoulder arthroplasty at our institution between the years of 2010 and 2020. Data was prospectively collected and retrospectively reviewed for post-operative range of motion and strength in patients with revision surgery and compared to controls. Measurements were collected preoperatively and postoperatively including range of motion and strength in the affected and unaffected shoulder. We collected patient reported outcome measures in person and via phone to identify subjective outcomes of total shoulder arthroplasty. Average final follow-up was 5.27 years. Results: Our total patient sample was split between three groups: those with primary anatomic arthroplasty those who underwent primary reverse arthroplasty, and those who were revised to a reverse shoulder arthroplasty. All three groups had significant improvements in abduction and forward elevation from their pre-operative baseline to two years follow-up. Primary reverse had a significant improvement over revision reverse in abduction at one year follow-up. For all other range of motion measurements, there was no statistically significant difference at 2 years between primary and revision reverse shoulder arthroplasty. Patient reported outcomes had a significant increase from pre-op to most recent follow-up in all three groups. Conclusion: Overall, our data suggest there is an improvement in outcomes with both primary and revision surgeries, and that results after revision reverse total shoulder arthroplasty may be comparable to primary reverse total shoulder arthroplasty.

Biomechanical Comparison of Two Surgical Repair Techniques of the Distal Biceps Tendon.

Purpose: This study aimed to characterize the relationship between the distal biceps tendon force and the supination and flexion rotations during the initiation phase and to compare the functional efficiency of anatomic versus nonanatomic repairs. Methods: Seven matched pairs of fresh-frozen cadaver arms were dissected to expose the humerus and elbow while preserving the biceps brachii, elbow joint capsule, and distal radioulnar soft tissue complex. For each pair, the distal biceps tendon was severed with a scalpel and then repaired with bone tunnels placed at either the anterior (anatomic) or the posterior (nonanatomic) aspect of the bicipital tuberosity on the proximal radius. A supination test with 90° of elbow flexion and an unconstrained flexion test were conducted on a customized loading frame. The biceps tension was applied incrementally at 200 g per step, whereas the radius rotation was tracked with a 3-dimensional motion analysis system. The tendon force needed to produce a degree of supination or flexion was derived as the regression slope of the tendon force-radial rotation plots. A two-tailed paired t test was performed to compare the difference between the anatomic repair and the nonanatomic repair cadavers. Results: Significantly greater tendon force was required to initiate the first 10° of supination with the elbow in flexion for the nonanatomic group compared with the anatomic group (1.04 ± 0.44 N/degree vs 0.68 ± 0.17 N/degree, P = .02). The average nonanatomic to anatomic ratio was 149% ± 38%. No difference existed between the two groups in the mean tendon force needed to produce the degree of flexion. Conclusions: Our results show that anatomic repair is more efficient in producing supination than nonanatomic repair, but only when the elbow is in 90° of flexion. When the elbow joint is not constrained, the nonanatomic supination efficiency improved, and the difference between the techniques was not significant. Clinical relevance: The present study added to the body of evidence in comparing anatomic versus nonanatomic repair of the distal biceps tendon and serves as a foundation for future biomechanical and clinical studies in this topic. Given no difference when the elbow joint was not constrained, one could argue that surgeon comfort and preference could guide which technique to use when addressing the distal biceps tendon tears. More studies will be needed to clearly define whether there will be a clinical difference between the two techniques.

Assessment of 2 distinct anatomical landmarks for suprascapular nerve injection: a cadaveric study.

BACKGROUND: The suprascapular nerve block (SSNB) is a commonly used procedure for the management of pain in various shoulder pathologies. Both image-guided and landmark-based techniques have been utilized successfully for SSNB, though more consensus is needed regarding the optimal method of administration. This study aims to evaluate the theoretical effectiveness of a SSNB at 2 distinct anatomic landmarks and propose a simple, reliable way of administration for future clinical use. METHODS: Fourteen upper extremity cadaveric specimens were randomly assigned to either receive an injection 1 cm medial to the posterior acromioclavicular (AC) joint vertex or 3 cm medial to the posterior AC joint vertex. Each shoulder was injected with a 10 ml methylene blue solution at the assigned location, and gross dissection was performed to evaluate the anatomic diffusion of the dye. The presence of dye was specifically assessed at the suprascapular notch, supraspinatus fossa, and spinoglenoid notch to determine the theoretic analgesic effectiveness of a SSNB at these 2 injection sites. RESULTS: Methylene blue diffused to the suprascapular notch in 57.1% of the 1-cm group and 100% of the 3-cm group, the supraspinatus fossa in 71.4% of the 1-cm group and 100% of the 3-cm group, and the spinoglenoid notch in 100% of the 1-cm group and 42.9% of the 3-cm group. CONCLUSION: Given its superior coverage at the more proximal sensory branches of the suprascapular nerve, a SSNB injection performed 3 cm medial to the posterior AC joint vertex provides more clinically adequate analgesia than an injection site 1 cm medial to the AC junction. Performing a SSNB injection at this location allows for an effective method of anesthetizing the suprascapular nerve.

Reverse shoulder arthroplasty in upper extremity ambulators: a matched-cohort analysis.

BACKGROUND: Upper extremity ambulators (UEAs) who require prolonged use of assistive devices for mobility have a high incidence of shoulder pathology secondary to increased stress across the shoulder joint with upper extremity weight-bearing. Reverse shoulder arthroplasty (RSA) for rotator cuff arthropathy has historically been associated with increased complications in UEA, but more recent studies have shown more promising outcomes. The objective of this study is to evaluate clinical outcomes and complication rates between these 2 groups to define the relative risk of RSA in the UEA population and identify opportunities to improve treatment outcomes. METHODS: An institutional review board-approved retrospective chart review was performed in patients who underwent RSA at our institution by the senior author from 2004 to 2019. UEAs were defined as patients who used regular upper extremity assistive devices for community ambulation before initial consultation for the surgical extremity. Pre- and postoperative range of motion, visual analog scale scores, American Shoulder and Elbow Surgeons scores, Constant-Murley scores, and Simple Shoulder Test scores were measured at defined intervals. Complications including infection, instability, and need for revision surgery were also compared. All patients were followed for a minimum of 2 years postoperatively. RESULTS: A total of 159 RSA procedures (70 UEAs, 89 controls) were performed during the study period. On average, UEA patients had more preoperative pain and less shoulder function than controls, with statistically significant differences in visual analog scores (6.897 vs. 5.532, P = .0010) and American Shoulder and Elbow Surgeons scores (33.50 vs. 40.20, P = .0290), respectively. Despite the lower baseline values, UEA patients experienced excellent postoperative improvement, leading to similar postoperative pain and shoulder function except for a lower average forward flexion in the UEA group (127° vs. 135°, P = .0354). Notching and complication rates were also similar between the 2 groups, with notching rates of 59% and 50% and complication rates of 14.3% and 13.5% in the UEA and control groups, respectively. CONCLUSIONS: RSA in the UEA population can achieve similar pain and functional outcomes as compared with age-matched controls without a significant increase in complication rates; however, further studies are required to assess long-term comparative outcomes in this challenging patient population.

Is the radial groove a myth? Is the radial nerve in direct contact with the posterior humerus?

BACKGROUND: The radial groove is known as a sulcus on the posterior humerus and protects the radial nerve from adjacent muscle and soft tissue. In the literature, there exists heterogeneity regarding the presence of an actual radial groove and the radial nerve's interaction with the periosteum of the humerus. This study aimed to determine if there is a real radial groove, "sulcus," and define the relationship between the radial nerve and the periosteum of the posterior humerus. METHODS: Eighteen fresh-frozen cadaveric specimens were dissected using a posterior triceps splitting approach. The radial nerve's interaction with the periosteum of the humerus was determined. The presence of a visible and palpable radial groove was also examined. RESULTS: In 56% of specimens, the radial nerve was directly seated over the periosteum of the posterior humerus (direct contact between the nerve and bone). In comparison, 44% of specimens had a layer of the medial head of the triceps brachii muscle fibers interposition between the nerve and bone. 89% of specimens had no visible or palpable radial groove. In 11% of specimens, there was mild palpable depression. CONCLUSION: This study shows that the radial groove may not exist and is probably not a true anatomical structure. In addition, the nerve is in direct contact with the posterior periosteum of the humerus in most specimens. These anatomic relationships and findings add to the anatomical understanding of the radial nerve, which helps during operative approaches and fixation of the humerus.

Rotator cuff repair in upper extremity ambulators: an assessment of longitudinal outcomes.

Background: Individuals who rely on wheelchairs, walkers, and crutches for ambulation have an increased incidence of rotator cuff tears due to altered shoulder biomechanics and increased force transmission across the shoulder joint. The purpose of our study is to review our longitudinal outcomes treating upper extremity ambulators to guide patient expectations and identify risk factors for rotator cuff repair failure. Methods: A total of fifteen patients were included after a cohort of thirty-nine patients were identified. The mean age was 54.9 years at the time of index rotator cuff repair, with each patient requiring either wheelchair, cane, walker, or crutches for ambulation. Clinical outcomes were measured (strength, range of motion, and pain scores), and patient-reported outcome scores (American Shoulder and Elbow Surgeons, Simple Shoulder Test, and University of California Los Angeles functional shoulder assessment tool) were obtained. No follow-up imaging was obtained unless indicated by a change in clinical status. Results: Within our cohort, 14 of 15 (93%) presented with supraspinatus tears, 7 of 15 (47%) with infraspinatus tears, and only 3 of 15 (20%) with subscapularis pathology. Additionally, the rates of concurrent biceps pathology or acromioclavicular joint pathology were significant at 53% and 73%, respectively. Only one patient in our cohort experienced known failure of cuff repair, despite longitudinal follow-up at an average of 97 months following surgery, however, routine follow-up imaging was not obtained. There were statistically significant improvements in visual analog scale pain scores, forward flexion ROM and strength, and abduction ROM. Additionally, statistically significant improvements were noted in all patient-reported outcome scores measured. Conclusion: Despite the apparent risks associated in rotator cuff repair in upper extremity ambulators, these patients demonstrate clinically significant improvements following surgery. Appreciating additional pathology beyond the rotator cuff is important in formulating a treatment plan.

Shoulder complex kinematics pre- and post- rotator cuff repair.

This study investigated shoulder complex joint kinematics and functional outcomes before and after full-thickness supraspinatus rotator cuff repair. Nine adults (mean age 63.4 ±â€¯6.2 years) participated in three test sessions: 0-12 weeks pre-operatively, 9-12 weeks, and 22-30 weeks post-operatively. Upper extremity kinematics of the surgical arm's glenohumeral, acromioclavicular, sternoclavicular and thoracohumeral joints over the duration of a hair combing task were quantified with motion analysis using inverse kinematics. The UCLA Shoulder Rating and Simple Shoulder Test shoulder health outcomes were administered at each session to determine patients' perceived function of their surgical shoulder. Results indicated multiple significant increases over time among the three joints comprising the shoulder complex in the coronal and transverse planes, despite no increases in thoracohumeral motion, and suggest that thoracohumeral motion alone does not provide a comprehensive assessment. Interestingly, more significant increases were observed at the 6-month evaluation than the 3-month evaluation, which is not aligned with the standard rehabilitation endpoint. Thus, our findings suggest that clinicians should evaluate all joints of the shoulder complex during longer-term rehabilitation assessment. Ultimately, knowledge of patients' pre-operative and post-operative shoulder complex kinematics may help to improve rehabilitation to promote improved patient outcomes.

Entrapment of the Extensor Indicis Proprius Tendon after Open Reduction and Internal Fixation of Distal Ulna: Case Report and Discussion of the Diagnosis and Surgical Result.

Entrapment of the extensor indicis proprius (EIP) after open reduction and internal fixation (ORIF) of the distal ulna with a plate and screw construct is rare. By literature review, we found evidence of such complication associated with distal radius fracture, but no past reports relating to the distal ulna. ORIF of the distal ulna is a common procedure for both fracture treatment and deformity correction. Due to the EIP muscle originating primarily from the dorsoradial surface of the distal ulna and the adjacent interosseous membrane, the muscle may be damaged or compressed by a fixation plate during ORIF, resulting in entrapment. We present two case reports of this rare complication, describing the method of clinical diagnosis, surgical treatment, and outcome. Our accompanying cadaver dissection provides an explanation for proper plate positioning during ORIF of the ulna to reduce the risk of EIP entrapment.

Outcomes of shoulder replacement in humeral head avascular necrosis.

BACKGROUND: This retrospective review evaluated 25 patients with 29 shoulders treated with arthroplasty for humeral head avascular necrosis (HHAVN) between 2004 and 2015. We hypothesized that regardless of implant, radiographic stage, or etiology, patients would appreciate significant improvement in pain, range of motion, and shoulder functionality after surgical intervention. METHODS: Data were obtained by record review on all patients meeting inclusion criteria. Outcomes were evaluated using Simple Shoulder Test, Modified Constant Score, University of California Los Angeles Shoulder Rating Scale, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form. The data were assessed by all patients and subcategories (treatment, avascular necrosis stage, and underlying cause). RESULTS: At a mean follow-up of 3.9 years (range, 1-8.5 years), all patients who underwent operative intervention for HHAVN showed statistically significant improvement in functionality measurements (P < .01). Patients who underwent total shoulder arthroplasty (TSA) noted higher median outcome scores and greater improvement in all scoring methods compared with their hemiarthroplasty counterparts. The high-stage disease shoulders showed similar trends over low-stage counterparts. The shoulders in the trauma causal group had the highest scores in 3 of 4 outcome measures and favorable change in all scoring methods. These differences were not statistically significant (P > .05). No revision arthroplasties were required. Minor complications (suture abscess and intraoperative calcar fracture requiring cabling) occurred in 2 TSA patients. CONCLUSIONS: Our outcomes demonstrate that in the short- to midterm follow-up, TSA or hemiarthroplasty is a safe and equally effective treatment for patients diagnosed with HHAVN regardless of etiology and radiographic staging.

Influence of preoperative opioid use on postoperative outcomes and opioid use after arthroscopic rotator cuff repair.

BACKGROUND: Recent orthopedic research has questioned the effect of opioid use on surgical outcomes. This study investigated this in the context of arthroscopic rotator cuff repair. We hypothesized that preoperative opioid use would be associated with inferior outcomes and greater postoperative opioid requirements. METHODS: A database query identified adult patients with full-thickness or partial-thickness supraspinatus tears surgically treated between 2011 and 2015. Preoperative and postoperative outcomes scores (active range of motion [AROM], American Shoulder and Elbow Surgeons [ASES], Constant scores, Simple Shoulder Test [SST], and visual analog scale [VAS] for pain) and postoperative opioid use were retrospectively recorded. Patients with less than 2 years of follow-up data at the time of the retrospective review were contacted for prospective ASES, SST, and VAS data collection. RESULTS: A total of 200 patients, 44 of whom received opioids preoperatively, were identified for inclusion. Patients prescribed preoperative opioids had consistently inferior preoperative and postoperative outcomes scores; however, the magnitudes of improvement were not significantly different between groups. Postoperatively, patients in the preoperative opioid group received 1.91 (95% confidence interval, 1.31-2.78) times more opioids over a postoperative course of treatment that was 2.73 (95% confidence interval, 1.62-4.59) times longer. In addition to having a greater proportion of women, this group also had significantly higher rates of certain comorbidities, including back pain, depression, degenerative joint disease, and chronic pain conditions. CONCLUSIONS: All patients demonstrated significant improvements in outcomes scores after surgical repair that were not significantly different between groups. However, patients taking opioids preoperatively did not ultimately reach the same level of functionality and had substantially greater opioid requirements postoperatively.

Pre-operative corticosteroid injections improve functional outcomes in patients undergoing arthroscopic repair of high-grade partial-thickness rotator cuff tears.

BACKGROUND: Subacromial corticosteroid injections (CSI's) are a common non-surgical treatment for rotator cuff tears. Few studies have assessed the effects of pre-operative CSI's on postoperative functional outcomes. METHODS: A retrospective analysis was conducted of 132 patients with high-grade, partial-thickness rotator cuff tears (PTRCT's). The subjects were divided into two groups based on whether they received a CSI or not. The CSI group was further divided into three subgroups based on when they received a pre-operative injection: 0-3 months, 3-6 months, >6 months before surgery. The Visual Analog Scores (VAS), American Shoulder and Elbow Surgeon scores (ASES), and Constant scores were recorded prior to surgery and at a one-year post-operative follow-up appointment for each subject. RESULTS: Patients who received a pre-operative CSI (n=92) improved significantly more than the non-injection group (n=40) in all outcome measures. The 0-3 months injection subgroup experienced a significant increase in ASES and Constant score (p=0.019 and 0.014, respectively) compared to the other two subgroups, but the VAS score decrease only trended toward significance (p=0.091). The sample as a whole experienced significant improvement in all three outcome measures. CONCLUSION: Patients undergoing arthroscopic repair of a high-grade PTRCT may benefit from a pre-operative CSI 0-3 months before surgery. LEVEL OF EVIDENCE: IIb.

Assessment of Kinematics and Electromyography Following Arthroscopic Single-Tendon Rotator Cuff Repair.

BACKGROUND: The increasing demand for rotator cuff (RC) repair patients to return to work as soon as they are physically able has led to exploration of when this is feasible. Current guidelines from our orthopedic surgery clinic recommend a return to work at 9 weeks postoperation. To more fully define capacity to return to work, the current study was conducted using a unique series of quantitative tools. To date, no study has combined 3-dimensional (3D) motion analysis with electromyography (EMG) assessment during activities of daily living (ADLs), including desk tasks, and commonly prescribed rehabilitation exercise. OBJECTIVE: To apply a quantitative, validated upper extremity model to assess the kinematics and muscle activity of the shoulder following repair of the supraspinatus RC tendon compared to that in healthy shoulders. DESIGN: A prospective, cross-sectional comparison study. SETTING: All participants were evaluated during a single session at the Medical College of Wisconsin Department of Orthopaedic Surgery's Motion Analysis Laboratory. PARTICIPANTS: Ten participants who were 9-12 weeks post-operative repair of a supraspinatus RC tendon tear and 10 participants with healthy shoulders (HS) were evaluated. METHODS: All participants were evaluated with 3D motion analysis using a validated upper extremity model and synchronized EMG. Data from the 2 groups were compared using multivariate Hotelling T2 tests with post hoc analyses based on Welch t-tests. MAIN OUTCOME MEASUREMENTS: Participants' thoracic and thoracohumeral joint kinematics, temporal-spatial parameters, and RC muscle activity were measured by applying a quantitative upper extremity model during 10 ADLs and 3 rehabilitation exercises. These included tasks of hair combing, drinking, writing, computer mouse use, typing, calling, reaching to back pocket, pushing a door open, pulling a door closed, external rotation, internal rotation, and rowing. RESULTS: There were significant differences of the thoracohumeral joint motion in only a few of the tested tasks: comb maximal flexion angle (P = .004), pull door internal/external rotation range of motion (P = .020), reach abduction/adduction range of motion (P = .001), reach flexion/extension range of motion (P = .001), reach extension minimal angle (P = .025), active external rotation maximal angle (P = .012), and active external rotation minimal angle (P = .004). The thorax showed significantly different kinematics of maximal flexion angle during the call (P = .011), mouse (P = .007), and drink tasks (P = .005) between the 2 groups. The EMG data analysis showed significantly increased subscapularis activity in the RC repair group during active external rotation. CONCLUSIONS: Although limited abduction was expected due to repair of the supraspinatus tendon, only a single ADL (reaching to back pocket) had a significantly reduced abduction range of motion. Thoracic motion was shown to be used as a compensatory strategy during seated ADLs. Less flexion of the thorax may create passive shoulder flexion at the thoracohumeral joint in efforts to avoid active flexion. The RC repair group participants were able to accomplish the ADLs within the same time frame and through thoracohumeral joint kinematics similar to those in the healthy shoulder group participants. In summary, this study presents a quantification of the effects of RC repair and rehabilitation on the ability to perform ADLs. It may also point to a need for increased rehabilitation focus on either regaining external rotation strength or range of motion following RC repair to enhance recovery and return to the workforce. LEVEL OF EVIDENCE: III.

High-Grade Articular, Bursal, and Intratendinous Partial-Thickness Rotator Cuff Tears: A Retrospective Study Comparing Functional Outcomes After Completion and Repair.

We conducted a study to assess the impact of tear location on functional outcomes in high-grade partial-thickness rotator cuff tears (PTRCTs) after arthroscopic completion and repair. Retrospectively, we evaluated the preoperative and postoperative findings of 60 patients who underwent arthroscopic completion and repair of Ellman grade 3 partial-thickness tears of the supraspinatus. The 60 patients were grouped by tear subtype (20 articular, 20 bursal, 20 intratendinous) as identified by preoperative imaging and confirmed at time of surgery. After surgery, the 3 subtypes showed similar significant (P < .001) improvements in American Shoulder and Elbow Surgeons scores (articular, 46.9, 85.1; bursal, 44.3, 80.3; intratendinous, 43.6, 86.1), Constant scores (articular, 54.3, 79.4; bursal, 49.9, 75.0; intratendinous, 56.8, 80.9), and visual analog scale scores (articular, 5.1, 1.2; bursal, 5.8, 1.6; intratendinous, 6.0, 1.2). Our study findings validate use of the current algorithm for Ellman grade 3 PTRCTs of the supraspinatus and advocate their completion and repair, regardless of tear location.

Ultrasound Imaging Improves Identification of Prominent Hardware in the Surgical Treatment of Distal Radius Fractures: A Cadaveric and Prospective Clinical Study.

Background Volarly applied locking plates are one of several current treatment options for displaced fractures of the distal radius. Presently, surgeons use intraoperative depth gauges and fluoroscopy to select and confirm proper screw length. The contour of the dorsal cortex beneath the extensor compartments along with fracture comminution may limit the accuracy of screw length selection. Question/Purpose To evaluate the accuracy of ultrasound (US) and fluoroscopy in the detection of dorsally prominent screws placed during volar plating of experimentally created distal radius fractures and extend this prospectively into the clinical setting. Patients and Methods Distal radius fractures were experimentally induced in fresh cadaveric arms. The fractures were then internally fixated with volar locking plates utilizing fluoroscopic imaging. US imaging of the dorsal surface of the radius was then performed followed by dorsal dissection and direct caliper measurements to quantitate screw tips as recessed, flush, or protruding from the dorsal cortex. A small, prospective clinical study was also conducted to validate the clinical usefulness of using US to provide additional information regarding screw tip prominence. Results Our study demonstrated that US was able to detect dorsally prominent screw tips not visible on fluoroscopy. Cadaveric dissection showed a higher statistical correlation between US imaging and actual prominence than between fluoroscopy and actual prominence. Conclusions US examination after volar plate fixation of comminuted distal radius fractures may detect dorsal screw tip prominence when screw lengths are selected to engage the dorsal cortex. Level of Evidence IV.

The "Thumbs-up" sign and trapeziometacarpal joint injection: a useful clinical indicator.

BACKGROUND: Several clinical studies investigating the accuracy and efficacy of trapeziometacarpal injection exist. Some studies utilize anatomical landmarks for proper injection placement while others utilize modalities including ultrasound and fluoroscopy. The changes of limb position that occur at the time of intra-articular injection can provide valuable visual and tactile feedback to the clinician. The purpose of this study is to investigate the occurrence of the "Thumbs-up" sign with injection of the thumb trapeziometacarpal joint as a useful and reliable clinical indicator of intra-articular trapeziometacarpal injection and correlate level and duration of pain relief. METHODS: Trapeziometacarpal joint injections were performed on twenty-seven thumbs utilizing anatomic landmarks. At the time of injection, the presence or absence of the "Thumbs-up" sign was noted, and needle location was verified after injection with orthogonal mini-C arm fluoroscopic images. Visual analog pain scale scores were obtained pre-injection and by follow-up telephone calls at 1 week, 6 weeks, and 3 months post injection. RESULTS: Twenty-four of twenty-seven injections demonstrated a positive "Thumbs-up" sign. There were three negative "Thumbs-Up" injections. The thumbs-up sign demonstrated a 92.3 % sensitivity. Eighteen of twenty-seven thumbs had sustained relief at 3 months post injection. CONCLUSIONS: The "Thumbs-up" sign is a practical clinical tool that gives the practitioner important visual feedback at the time of injection. Patient relaxation and joint compliance are limiting factors. The "Thumbs-up" sign is an inexpensive indicator of successful intra-articular injection and may obviate the need and expense of advanced imaging modalities at the time of injection.

Biomechanical evaluation of locking plate radial shaft fixation: unicortical locking fixation versus mixed bicortical and unicortical fixation in a sawbone model.

PURPOSE: Compression plating is a commonly accepted technique for treating diaphyseal forearm fractures. The purpose of this study was to evaluate the stabilizing effects of two hybrid fixations that replace the end screws of a locked unicortical fixation with bicortical (locked or unlocked) screws and to compare these hybrid fixations to an unlocked bicortical fixation. METHODS: Sixteen composite radius sawbones were equally divided into 4 groups. We performed a midshaft osteotomy and plate fixation on the volar surface with 1 of 4 different constructs: 3 unlocked bicortical screws on each side (unlocked bicortical), 3 locked unicortical screws on each side (locked unicortical), or with 2 unicortical locked screws near the fracture and 1 bicortical unlocked (unlocked hybrid) or locked (locked hybrid) screw distant from the fracture on each end (LCP system, Synthes USA, Paoli, PA). Specimens were tested in nondestructive 4-point bending and torsion on a servo-hydraulic material testing system. The construct stiffness was obtained from the linear portion of the load-displacement curves after 3 cycles of preconditioning. The results from all groups were compared using analysis of variance and post hoc Bonferroni tests. RESULTS: Under torsional loads, replacing the end screws of a locked unicortical configuration with bicortical screws significantly improved the construct stiffness: 57.6% increase for the locked screws and 51.6% increase for the unlocked. In anteroposterior (AP) bending, the highest improvement over the locked unicortical configuration came from the locked hybrid constructs (42.9% increase). When compared with the unlocked bicortical configuration, both hybrid constructs provide equivalent stability in torsion but superior stability in AP bending. CONCLUSIONS: Replacing a single set of unicortical locked screws with locked or unlocked bicortical screws distant from the fracture site improves torsional stability of the construct by more than 50%, giving stability equal to standard unlocked plating. The hybrid fixation, however, with locked bicortical end screws has the best stability in AP bending.

Biomechanical comparison of fixed-angle volar plate versus fixed-angle volar plate plus fragment-specific fixation in a cadaveric distal radius fracture model.

PURPOSE: To test the hypothesis that combining orthogonal fragment-specific fixation with volar fixed-angle fixation provides markedly higher interfragment stability and construct strength compared with volar fixed-angle fixation alone. METHODS: Eight matched pairs of fresh cadaveric hand and forearm specimens were potted upright in cement. Flexor and extensor tendons were isolated at insertion sites and sutured into a looped bundle for loading in flexion and extension, respectively (up to 61 N). Osteotomies to simulate an AO type C2, 3-part fracture pattern were created with a saw. One randomized specimen from each pair received a locking volar plate and a radial pin plate (VP+PP), and the other received a locking volar plate only (VP). The relative angular displacements between the radial, ulnar, and proximal fragments were obtained with a motion analysis system. After stability tests, specimens were compressed to failure in a wrist-extended position on a material testing machine. Paired t tests were used to compare the interfragment displacement, construct stiffness, and strength between the 2 groups. RESULTS: Comparing fragment displacement in the VP+PP and VP groups showed that with flexion-extension and radial-ulnar deviation, distal fragment displacement was reduced to a statistically significant degree. The VP+PP group also showed higher failure strength and construct rigidity than the VP group. CONCLUSIONS: In a simulated cadaveric model of the distal radius intra-articular fracture, the combined technique of fragment-specific plating with volar fixed-angle fixation alone provides superior biomechanical strength and stability over the volar fixed-angle fixation alone.