Jessica DiVenere

Pectoralis Major Repair: A Biomechanical Analysis of Modern Repair Configurations Versus Traditional Repair Configuration

Background: Pectoralis major (PM) ruptures are increasingly common, and a variety of surgical techniques have been described. However, tested techniques have demonstrated diminished strength with inadequate restoration of the footprint and suture failure at relatively low loads. Purpose/Hypothesis: The purpose was to biomechanically compare PM transosseous suture repair (current gold standard) to modern PM repair techniques that use larger caliber sutures, suture tape, and unicortical button fixation (UBF). The null hypothesis was that there would be no mechanical difference between repair techniques and no difference in the amount of footprint restoration. Study Design: Controlled laboratory study. Methods: Twenty-four fresh-frozen cadaveric shoulders controlled for age and bone mineral density were randomized equally to 4 groups: (1) UBF, suture tape; (2) UBF, No. 5 suture, suture tape; (3) bone trough with No. 2 suture; and (4) native PM tendon group; all groups were tested to failure. The specimens were tested under cycling loads (10 N to 125 N) with a final load-to-failure test at 1 mm/s. Failure modes were classified by location and cause of rupture based on optical markers, while tendon footprint length was measured to determine amount of footprint restoration. Results: For fixation strength, the mean peak load was significantly greater in the native tendon (1816 ± 706 N) versus UBF/No. 5 suture/suture tape (794 ± 168 N), UBF/suture tape (502 ± 201 N), and bone trough (492 ± 151 N) (P < .001 for all). UBF/No. 5 suture/suture tape featured the lowest displacement superiorly (1.09 ± 0.47 mm) and inferiorly (1.14 ± 0.39 mm) with a significant difference compared with bone trough. With regard to tendon footprint reapproximation, cortical button fixation best approximated native tendon footprint length versus bone trough. Conclusion: Based on peak failure load, the UBF/No. 5 suture/suture tape construct demonstrated 61% greater construct strength than a traditional bone trough technique. Moreover, displacement after cyclic loading was by far smallest in the UBF/No. 5 suture/suture tape construct. Therefore, repair constructs with larger caliber suture and suture tape provide a measurable improvement in construct strength versus traditional PM repair techniques in a biomechanical model and may be advantageous for repair. Clinical Relevance: Cortical button fixation with larger caliber suture and suture tape allows for a significantly better PM repair than more traditional techniques at the time of surgery, which may ultimately result in improved clinical outcomes if implemented in surgical practice.

Sternoclavicular Joint Anatomy and Pathology

The sternoclavicular joint is a diarthrodial synovial joint, which represents the only true articulation between the upper extremity and the axial skeleton. A fibrocartilaginous disk bisects the joint forming two distinct synovial cavities. The articulating surfaces of this joint are lined with fibrocartilage. There is little inherent osseous stability between the articulating surfaces of the bulbous medial clavicle and the shallow manubrium. Ligamentous connections, primarily the anterior and posterior sternoclavicular ligaments, play a crucial role stabilizing this joint. Anatomically, the joint is located in close proximity to the trachea, the brachiocephalic vein as it divides into the internal jugular and subclavian veins, the right brachiocephalic artery as it divides into the common carotid and subclavian artery, the left common carotid artery, and the left subclavian artery. Symptomatic pathology of the joint is uncommon, which is reflected by the paucity of literature on the structure. Most conditions can be managed conservatively with acceptable results. However, posterior dislocations represent an emergency, requiring urgent treatment given the potential for disastrous neurovascular or airway damage.

Shoulder Acromioclavicular and Coracoclavicular Ligament Injuries: Common Problems and Solutions

Injuries to the acromioclavicular joint and coracoclavicular ligaments are common. Many of these injuries heal with nonoperative management. However, more severe injuries may lead to continued pain and shoulder dysfunction. In these patients, surgical techniques have been described to reconstruct the function of the coracoclavicular ligaments to provide stable relationship between the clavicle and scapula. These surgeries have been fraught with high complication rates including clavicle and coracoid fractures, infection, loss of reduction and fixation, hardware migration, and osteolysis. This article reviews common acromioclavicular and coracoclavicular repair and reconstruction techniques and associated complications, and provides recommendations for prevention and management.

Arthroscopic Repair of Extended Labral Tears After a Traumatic Shoulder Dislocation

This chapter will focus on the diagnostic, surgical technique and expected outcomes after a traumatic shoulder dislocation involving 270° labral tears. Traumatic labral tears involving the anterior, inferior, and posterior aspects of the glenoid fossa represent a unique subpopulation of shoulder instability. Orientation, location, and dimension of labral tears can be used to group them into categories to select the appropriate procedure. The continued development of shoulder arthroscopic techniques and MRI imaging quality has led to a precise description of tear patterns to identify and characterize labral injury. The described 270° labral tear extends anteriorly, inferiorly, and to the mid glenoid level posteriorly, accounting for 270° of the glenoid fossa. The superior labrum and biceps anchor complex are preserved without any pathology on arthroscopic examination. In the literature are different combinations of labral tears described pointing out that the pathology can exist in any one of the four glenoid quadrants and extend in any direction (Lo and Burkhart, Owens et al., Tokish et al.). It is important to be aware and detect those extended tears prior to surgery with adequate clinical examination and imaging diagnostic to be prepared.

First Metatarsophalangeal Contact Properties Following Proximal Opening Wedge and Scarf Osteotomies for Hallux Valgus Correction: A Biomechanical Study:

Background: Proximal opening wedge osteotomy (POWO) is an established procedure for moderate to severe hallux valgus. A common concern of this procedure is that it results in lengthening of the first metatarsal, which could cause increased intra-articular pressure of the first metatarsophalangeal joint (MTP) and may ultimately lead to arthritis because of these altered mechanics. The purpose of this study was to use a cadaveric model to compare intra-articular pressures and articulating contact properties of the MTP joint following either scarf osteotomy or POWO. Methods: Fresh-frozen cadaveric below-knee specimens with pre-existing hallux valgus (n = 12) and specimens without hallux valgus (n = 6, control group) were used. The hallux valgus specimens were stratified into 2 groups (n = 6 each): POWO or scarf osteotomy. The groups were matched based on the degree of deformity. Peak intra-articular pressure, force, and area were measured in all normal, preoperative, and postoperative specimens with a simulated weightbearing model. These measurements were made with a pressure transducer placed within the first MTP joint. Results: Postoperatively POWO group had slightly higher contact forces and pressures compared to the scarf group and lower contact forces and pressures than those of the normal group but were not statistically significant (P > .05). Normal specimens had higher intra-articular force, pressure, and area than postoperative specimens but the difference was not found to be significant. First metatarsal lengthening was found in both the scarf and POWO specimens; however, neither increase was found to be significant (P > .05). Conclusion: The results from this study show that after operative correction, contact properties of the fist MTP joint among normal, POWO, and scarf osteotomy groups revealed no significant differences. First MTP joints in those with hallux valgus had significantly lower contact force and pressure compared to those without hallux valgus. Clinical Relevance: With little long-term outcomes of proximal opening wedge osteotomy, this study will help predict the possibility of future MTP joint arthritis.

Repair Integrity and Clinical Outcomes Following Arthroscopic Rotator Cuff Repair A Prospective, Randomized Trial of Early and Delayed Motion Protocols

Objectives: To prospectively evaluate the effect of early versus delayed motion on repair integrity on 6-month postoperative magnetic resonance imaging (MRI) scans following rotator cuff repair, and to correlate repair integrity with clinical and functional outcomes. We hypothesized that repair integrity would differ between the early and delayed groups and that patients with repair failures would have worse clinical and functional outcomes. Methods: This was a prospective, randomized, single blinded clinical trial comparing an early motion (post-op day 2-3) to a delayed motion (post-op day 28) rehabilitation protocol following arthroscopic repair of isolated supraspinatus tears. All patients underwent MRI at 6 months post-operatively as part of the study protocol. A blinded board-certified and fellowship-trained orthopaedic surgeon (not part of the surgical team) reviewed operative photos and video to confirm the presence of a full thickness supraspinatus tear and to ensure an adequate and consistent repair. The same surgeon along with a blinded sports medicine fellowship-trained musculoskeletal radiologist independently reviewed all MRIs to determine whether the repair was intact at 6 months. Outcome measures were collected by independent evaluators who were also blinded to group assignment. These included the Western Ontario Rotator Cuff (WORC) index, Single Assessment Numeric Evaluation (SANE) ratings, pain scores, sling use, and physical exam data. Enrolled patients were followed at 6 weeks, 6 months, and 1 year. Results: From October 2008 to April 2012, 73 patients met all inclusion criteria and were willing to participate. 36 patients were randomized to delayed motion and 37 were randomized to early motion. The final study group at 6 months consisted of 58 study participants. Postoperative MRIs were obtained on all of these patients at 6 months regardless of whether or not they were progressing as expected. These MRIs demonstrated an overall failure rate of 29%. This did not differ significantly based on early or late motion, with 9 (26%) tears occurring in the delayed motion group compared to 10 (32%) in the early motion group (p=0.70). When patients with repair failures were compared to those with intact cuffs, no significant differences were detected in range of motion, strength, or WORC, SANE, or pain scores at 6 months or 1 year. Interestingly, however, at 6 weeks, both WORC and SANE scores were significantly better in patients who were later found to have repair failures on MRI (p<0.05). When evaluated irrespective of rehabilitation protocol, non-compliance with sling use was associated with higher failures rates (p<0.05). Conclusion: Repair failure rates do not significantly differ between patients randomized to early and delayed motion protocols following arthroscopic single tendon rotator cuff repair. Repair failure on MRI does not correlate with clinical outcome at 6 months or 1 year. However, better subjective outcome scores at 6 weeks are associated with higher rates of repair failure at 6 months.

First Metatarsophalangeal Contact Properties are Similar Following Proximal Opening Wedge and Scarf Osteotomies

Category: Bunion Introduction/Purpose: Proximal opening wedge osteotomy (POWO) is an established correctional procedure for moderate to severe hallux valgus. A common concern of this procedure is that it results in lengthening of the metatarsal which could cause increased intra-articular pressure of the first metatarsophalangeal joint (MTP), and may ultimately lead to arthritis due to these altered mechanics. The purpose of this study was to use cadaveric models to compare intra-articular pressures and articulating contact properties of the MTP joint following either scarf osteotomy or POWO. These were compared to normal cadaveric specimens. Our hypothesis was that the intra-articular pressure of the first MTP joint would be greater following the POWO compared to the scarf osteotomy. Methods: Fresh-frozen cadaveric below knee specimens with pre-existing hallux valgus (n=12) and specimens without arthritis or hallux valgus (n=6, control group) were used. The hallux valgus specimens were stratified into two groups (n=6 each): POWO or scarf osteotomy. The groups were matched based on the degree of deformity. Peak intra-articular pressure, force, and area were measured in all normal, preoperative and postoperative specimens. These measurements were made with a pressure transducer (Tekscan, Boston, Massachusetts) while a 50 N dorsiflexion load was applied via a wired loop on the first toe over 5 seconds and then released. Secondary outcomes included range of motion (ROM) and radiographic measurements. ROM was measured pre and postoperatively under fluoroscopy. 1-2 intermetatarsal angle (1-2 IMA), hallux valgus angle (HVA), and metatarsal length were measured on simulated weight-bearing radiographs. Statistical analyses were performed using unpaired Student’s t-test, paired Student’s t-test, and ANOVA with Bonferroni correction for post-hoc analysis. Results: Postoperatively, although POWO group had slightly higher contact forces and pressures compared to the scarf group, they were lower than those of the normal group. These comparisons had no statistically significant differences (P>0.05). Normal specimens had significantly higher force (P=0.012) and pressure (P=0.007) but similar contact area (P>0.05) compared to the preoperative hallux valgus specimens. Contact area were similar in normal, POWO, and scarf groups. There was no significant difference in ROM between all three groups. The first metatarsal was lengthened 1.36 mm +/- 1.39 mm in the POWO group and lengthened 1.54 mm +/- 2.27 mm in the scarf osteotomy group. Conclusion: The results from this study show that after surgical correction, contact properties of the fist MTP joint among normal, POWO, and scarf osteotomy groups revealed no significant differences. First MTP joints in those with hallux valgus have significantly lower contact force and pressure compared to those without hallux valgus. Our results provide biomechanical evidence that first MTP joint biomechanics are similar after POWO and scarf osteotomy.

Biomechanical Consequences of Excessive Patellar Distalization

Background: Iatrogenic patellar baja can be a result of excessive tibial tubercle distalization or overtightented patellar tendon repair. Tubercle distalization is increasing in popularity for the treatment of recurrent patella instability. Clinically, patellar baja can present as a debilitating problem with motion loss, increased pain, and arthrosis progression. However, previous biomechanical studies have not shown an increase in patellofemoral joint contact pressures. The purpose of this study is to examine the patellofemoral contact pressure after a tibial tubercle distalization osteotomy. Methods: Ten matched pair fresh-frozen cadaveric knees were studied. Average Blackburne-Peel ratio of the native knees was 0.91. The knees were placed on a testing rig, with a fixed femur and tibia mobile through 90° of flexion. Individual quadriceps heads and the iliotibial band were separated and loaded with 205 N in anatomic directions using a weighted pulley system. A straight tubercle distalization osteotomy of 1 cm was performed and fixed with screws, with and without a lateral release. Patellofemoral contact pressures were measured at 0°, 10°, 20°, 30°, 45°, 60°, and 90° of flexion using pressure-sensitive films on the medial and lateral trochlea. The contact force, area and pressure were measured at the following states: (1) native knee, (2) with distalization and (3) distalization with lateral release. Results: Average Blackburne-Peel ratio after distalization was 0.64. Tibial tubercle distalization resulted in a six fold increase in mean contact pressures at 0° (0.15 versus 0.90 MPa, p<0.001), and a 55% increase at 10° of flexion (0.70 versus 1.09 MPa, p=0.02). After distalization, total contact area was significantly higher at 0° of flexion (17.7 mm2 versus 58.4 mm2, p=0.02). Lateral release after distalization did not significantly change contact pressure (p>0.21). Conclusion: Our results suggest that patellar baja, as a result of excessive patellar distalization, can cause increased patellofemoral contact pressures during early flexion.

Postoperative Shoulder Stiffness After Rotator Cuff Repair

Postoperative shoulder stiffness (POSS) is an acquired loss of motion, occurring after a known surgical or traumatic event. Biomechanically, a stiff shoulder is one in which at least one of the shoulder’s motion interfaces has been compromised, thus, limiting maximal excursion. The definition of what POSS is remains controversial, with a wide variability in its definition. Incidence of POSS is variable and has been reported as high as 32.7 %. It accounts for one of the most common complications following surgical repair of the rotator cuff. Management of POSS is important as it can severely limit the activities of daily living. There remains a lack of consensus in regard to the etiology and prevention of POSS. This chapter discusses the various etiologies and risk factors for POSS after RCR, preoperative ROM and POSS, operative techniques and POSS, the postoperative surgical changes and their biomechanical impact on shoulder motion, and postoperative therapy protocols.