Acromial morphology is not associated with rotator cuff tearing or repair healing.

BACKGROUND: The purposes of this study were to determine whether acromial morphology (1) could be measured accurately on magnetic resonance images (MRIs) as compared to computed tomographs (CTs) as a gold standard, (2) could be measured reliably on MRIs, (3) differed between patients with rotator cuff tears (RCTs) and those without evidence of RCTs or glenohumeral osteoarthritis, and (4) differed between patients with rotator cuff repairs (RCRs) that healed and those that did not. METHODS: This is a retrospective comparative study. We measured coronal, axial, and sagittal acromial tilt; acromial width, acromial anterior and posterior coverage, and glenoid version and inclination on MRI corrected into the plane of the glenoid. We determined accuracy by comparison with CT via intraclass correlation coefficients (ICCs). To determine reliability, these same measurements were made on MRI by 2 observers and ICCs calculated. We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of an RCT or glenohumeral osteoarthritis. We then compared these measurements between those patients with healed RCRs and those with a retorn rotator cuff on MRI. In this portion, we only included patients with both a preoperative MRI and a postoperative MRI at least 1 year from RCR. Only those patients without tendon defects on postoperative MRIs were considered to be healed. In these patients, we also radiographically measured the critical shoulder angle. RESULTS: In a validation cohort of 30 patients with MRI and CT, all ICCs were greater than 0.86. In these patients, the inter-rater ICCs of the MRI measurements were >0.53. In our RCT group of 110 patients, there was greater acromial width [mean difference (95% confidence interval) = 0.1 (0, 0.2) mm, P = .012] and significantly less sagittal acromial tilt [9° (5°-12°), P < .001] than in our comparison group of 107 patients. A total of 110 RCRs were included. Postoperative MRI scans were obtained at a mean follow-up of 24.2 ± 15.8 months, showing 84 patients (76%) had healed RCRs. Aside from acromial width, which was 0.2 mm different and thus did not have clinical significance, there was no association between healing and any of the measured morphologic characteristics. Patients with healed repairs had significantly smaller tears in terms of both width (P < .001) and retraction (P < .001). CONCLUSION: Although the acromion is wider in RCTs, the difference of 0.1 mm likely has no clinical significance. The acromion is more steeply sloped from posteroinferior to anterosuperior in those with RCTs. These findings call into question subacromial impingement due to native acromial morphology as a cause of rotator cuff tearing. Acromial morphology, critical shoulder angle, and glenoid inclination were not associated with healing after RCR. This study does not support lateral acromioplasty.

Surgical Treatment for FAI: Arthroscopic and Open Techniques for Osteoplasty.

PURPOSE OF REVIEW: To review the relevant literature and techniques regarding arthroscopic and open treatment of femoroacetabular impingement (FAI). To discuss both the senior authors' preferred method of arthroscopic and open treatment of FAI. RECENT FINDINGS: Routine treatment of FAI has moved away from open techniques and is more focused arthroscopic methods. Arthroscopic treatment of FAI has more recently focused on differing techniques of hip access and capsular management. Open techniques still have a role in FAI, but indications for open management are focused on cases with more severe pathology. While arthroscopic techniques have shown better outcomes in the short term and higher return to play, it is not without risk and is a procedure with a steep learning curve. In cases of complex joint pathology, such as FAI coupled with dysplasia or Legg-Calve-Perthes, arthroscopy may be not indicated and an open approach preferred. We outline various techniques for both arthroscopic and open treatment of FAI and their outcomes when possible.

Blinded Ultrasound Examination of the Subscapularis Following Anatomic Shoulder Arthroplasty.

BACKGROUND: The subscapularis tendon is commonly released during shoulder arthroplasty, and its integrity and repair postoperatively have been shown important to help maximize patient function. However, diagnosing subscapular tendon failure can be difficult with magnetic resonance imaging secondary to metal artifact as well as very costly. PURPOSE: The purpose of this study was to assess the utility of ultrasound imaging in evaluating subscapularis integrity at specific time points following shoulder arthroplasty, in a blinded fashion. Secondarily, we report on the correlation between the condition of the subscapularis and quality-of-life outcome measures. STUDY DESIGN: Prospective case series. METHODS: Ultrasounds were completed preoperatively and postoperatively at 1 week as well as at 1, 3, and 6 months. Each was read by a single musculoskeletal radiologist and categorized as "intact," "torn," or "unclear." Clinical outcome was evaluated using the Western Ontario Osteoarthritis Shoulder (WOOS) index at these same time points. RESULTS: The final study group consisted of 35 procedures in 33 patients (19 females and 14 males, mean age 66 ± 9 years). Three patients had postoperative subscapularis failures that were confirmed in the operating room at the time of repair. Of 24 sonographs categorized as "unclear" in the postoperative period, the majority (n = 12, 50%) were taken at 1 week. Compared to preoperative scores, patients had lower WOOS scores at 1, 3, and 6 months postoperatively (P < .001). Correlation analysis did not reveal an association between the ultrasound readings and the WOOS scores postoperatively. CONCLUSION: The utility of ultrasound examination of the subscapularis tendon following shoulder arthroplasty is limited by timing and may be most useful when used by the physician within clinical context. Significant improvement was noted in disease-specific quality-of-life scores regardless of the status of the subscapularis tendon as read on ultrasound.

Arthroscopic Reduction and Fixation of a Lesser Trochanter Avulsion Nonunion.

Identifying and treating avulsion fractures of the pelvis and proximal femur in adolescent athletes has become increasingly more important as the rate of competitive sports participation has grown. The majority of these fractures can be treated conservatively, with most returning to full activity. Surgical treatment of these injuries has been traditionally indicated for >2 cm displacement, painful nonunion, symptomatic exostosis formation, or persistent pain and symptoms. Lesser trochanter avulsion injuries are extremely rare and literature outlining their surgical treatment lacking. We present our method of arthroscopic reduction and fixation of lesser trochanter avulsion nonunions.

Biomechanical Comparison of Olecranon Sled Versus Intramedullary Screw Tension Banding for Olecranon Osteotomies.

BACKGROUND: Olecranon osteotomies are frequently performed to gain access to the distal humeral articular surface. Repair of the osteotomy or fixation of a simple 2-part olecranon fracture with traditional tension band construct is often plagued by complication. Proximal migration and irritation attributed to hardware are common complications of the standard construct of an intramedullary screw with tension band and are causes for reoperation. PURPOSE: To compare the biomechanical performance, time of implant, and prominence of an intramedullary screw and tension band construct with that of a newer low-profile continuous loop tension band (Olecranon Sled) construct in an olecranon osteotomy model. STUDY DESIGN: Controlled laboratory study. METHODS: Chevron osteotomies were created in 6 matched pairs of fresh-frozen human elbows (mean age, 66 ± 16 years). Each matched pair was then randomly divided into 1 of 2 groups: fixation with a screw and tension band construct or the Olecranon Sled. Bone mineral density, implant prominence, and time for implantation were recorded. Following olecranon fixation, each specimen underwent cyclic loading of 0 to 10 N for 100 cycles (to simulate unresisted active range of motion) and then 0 to 500 N for 500 cycles (to simulate pushing up from a chair) to measure for any displacement at the osteotomy site. The constructs were then loaded to failure and compared. RESULTS: No differences were found in bone mineral density between the 2 groups (P = .290). When measured from the tip of the olecranon, the continuous loop tension band had a medial prominence of only 3.57 ± 0.4 mm, as opposed to the intramedullary screw fixation of 7.288 ± 0.762 mm (P = .027). Total time of implantation, including osteotomy preparation, was a mean 155 seconds shorter with the Olecranon Sled versus the traditional tension band (P < .05). Because of the fracture of 1 specimen during cyclic loading, it and its matched counterpart were excluded, and only 5 matched pairs were analyzed for displacement and load to failure. There were no significant differences between groups in load to failure or displacement during cyclic loading (P > .05). CONCLUSION: The Olecranon Sled device was found to have no difference in biomechanical strength from that of the standard intramedullary screw with tension band construct. The Olecranon Sled was also found to be significantly less prominent while being faster to implant than the intramedullary screw. CLINICAL RELEVANCE: Evaluating an alternative option to the standard tension band construct is important for patients with olecranon fractures or osteotomies, as standard techniques have been fraught with hardware issues and need for revision surgery.

Biomechanical Comparison of Epiphyseal Anterior Cruciate Ligament Fixation Using a Cortical Button Construct Versus an Interference Screw and Sheath Construct in Skeletally Immature Cadaveric Specimens.

BACKGROUND: Anterior cruciate ligament (ACL) ruptures have become increasingly common in pediatric and adolescent athletes. While multiple methods exist, all-epiphyseal ACL reconstruction is a popular technique in the skeletally immature patient. Given the high rate of reruptures in this population and the increasing number of commercially available fixation devices, biomechanical testing is crucial to understand the performance of these devices in pediatric epiphyseal bone. To our knowledge, there has not been a biomechanical analysis of ACL fixation devices in skeletally immature bone. PURPOSE: To compare cortically based button fixation with interference screw and sheath fixation in skeletally immature femoral epiphyseal cadaveric bone. Our hypothesis was that there would be no difference in peak load to failure, stiffness, or cyclic displacement between these 2 fixation constructs. STUDY DESIGN: Controlled laboratory study. METHODS: Fresh-frozen matched-pair knees from 3 pediatric cadaveric specimens were obtained. A synthetic graft was fixed in an all-epiphyseal femoral tunnel. Both the lateral and medial condyles were utilized to increase the sample size. Specimens were randomized and assigned to receive either an interference screw and sheath construct designed for pediatric patients or an adjustable loop cortical button. Biomechanical testing was performed to obtain ultimate load to failure, stiffness, total displacement after 500 cycles, and the failure mode for each condyle. RESULTS: Each medial and lateral condyle in 3 pairs of skeletally immature cadaveric knees (ages 7, 9, and 11 years) was utilized for testing. One specimen was excluded after it failed by having a transphyseal fracture. The median peak load to failure was 769.80 N (interquartile range [IQR], 628.50-930.41 N) for the screw and sheath group and 862.80 N (IQR, 692.34-872.65 N) for the button group (P = .893). The median displacement after 500 cycles for the screw and sheath group was 0.65 mm (IQR, 0.47-1.03 mm) and 1.13 mm (IQR, 0.96-1.25 mm) for the button group (P = .08). The median stiffness of the screw and sheath group was significantly higher than that of the button group (31.47 N/mm [IQR, 26.40-43.00 N/mm] vs 25.22 N/mm [IQR, 21.18-27.07 N/mm], respectively) (P = .043). CONCLUSION: When comparing femoral fixation with a screw and sheath construct developed for pediatric patients to an adjustable loop cortical button in skeletally immature bone, our results showed that fixation did not significantly differ with respect to cyclic displacement or peak load to failure. While the screw and sheath construct was significantly stiffer, its effect on clinical outcomes is not yet known. CLINICAL RELEVANCE: With regard to femoral fixation, there is no significant biomechanical difference between the use of cortically based button fixation or interference screw and sheath fixation in pediatric epiphyseal cadaveric bone.

A Biomechanical Analysis of Different Clavicular Tunnel Diameters in Anatomic Acromioclavicular Ligament Reconstruction.

PURPOSE: To evaluate the biomechanical stability of a tendon-to-clavicle bone interface fixation of a graft in revision acromioclavicular reconstruction. METHODS: Fifteen fresh-frozen cadaveric shoulders were used. All specimens underwent bone density evaluation. For the primary reconstruction, a 5-mm semitendinosus allograft was inserted into a 5-mm bone tunnel at 25 and 45 mm from the lateral end of the clavicle using a 5.5 × 8-mm PEEK (polyether ether ketone) tenodesis screw. Each single graft was fixed in a cryo-clamp and cyclically loaded from 5 to 70 N for 3,000 cycles, followed by load-to-failure testing at a rate of 120 mm/min to simulate the revision case. To simulate tunnel widening, the tunnels of the revision series were over-drilled with an 8-mm drill, and a 5-mm semitendinosus graft with an 8 × 12-mm PEEK tenodesis screw was inserted. Biomechanical testing was then repeated. RESULTS: The bone mineral density analysis showed a significantly higher density at the 45-mm hole compared with the 25-mm hole (P = .001). The ultimate load to failure increased from the 5.5-mm screw to the 8-mm screw at the 45-mm hole position (P = .001). There was no statistically significant difference at the 25-mm hole position (P = .934). No statistical significance for graft elongation comparing the 5.5-mm screw and the 8-mm screw at the 25-mm (P = .156) and 45-mm (P = .334) positions could be found. CONCLUSIONS: Comparable biomechanical stability for the tendon-to-bone interface fixation in different clavicular tunnel diameters simulating primary and revision reconstruction was achieved. CLINICAL RELEVANCE: There is a lack of literature regarding revision acromioclavicular joint reconstruction, but our biomechanical results show comparable stability to primary reconstruction. These data provide support for the use of anatomic acromioclavicular ligament reconstruction in revision cases.

Systemic Administration of Sclerostin Antibody Enhances Bone Morphogenetic Protein-Induced Femoral Defect Repair in a Rat Model.

BACKGROUND: Recombinant human bone morphogenetic protein (rhBMP)-2 is a potent osteoinductive agent; however, its clinical use has been reduced because of safety and efficacy concerns. In preclinical studies involving a critical-sized defect in a rat model, sclerostin antibody (Scl-Ab) treatment increased bone formation within the defect but did not result in reliable healing. The purpose of the current study was to evaluate bone repair of a critical-sized femoral defect in a rat model with use of local implantation of rhBMP-2 combined with systemic administration of Scl-Ab. METHODS: A critical-sized femoral defect was created in rats randomized into three treatment groups: local rhBMP-2 and systemic Scl-Ab (Scl + BMP), local rhBMP-2 alone, and collagen sponge alone (operative control). The Scl + BMP group received local rhBMP-2 (10 µg) on a collagen sponge placed within the defect intraoperatively and then twice weekly injections of Scl-Ab (25 mg/kg) administered postoperatively. The femora were evaluated at twelve weeks with use of radiography, microcomputed tomography (microCT), histomorphometric analysis, and biomechanical testing. RESULTS: At twelve weeks, all Scl + BMP and rhBMP-2 only samples were healed. No femora healed in the operative control group. Histomorphometric analysis demonstrated more bone in the Scl + BMP samples than in the samples treated with rhBMP-2 alone (p = 0.029) and the control samples (p = 0.003). MicroCT revealed that the Scl + BMP group had a 90% greater bone volume within the defect region compared with the rhBMP-2 group and a 350% greater bone volume compared with the operative control group (p < 0.001). Biomechanical testing showed that the group treated with Scl + BMP had greater torsional strength and rigidity compared with the rhBMP-2 group (p < 0.001 and p = 0.047) and the intact femoral control group (p < 0.001). Torque to failure was lower in the rhBMP-2 group compared with the intact femoral control group (p < 0.002). Mean energy to failure was higher in the Scl + BMP samples compared with the rhBMP-2 only samples (p = 0.001). CONCLUSIONS: In a critical-sized femoral defect in a rat model, local rhBMP-2 combined with systemic administration of Scl-Ab resulted in more robust healing that was stronger and more rigid than results for rhBMP-2 alone and intact nonoperative femora. CLINICAL RELEVANCE: Our study demonstrated that combining an osteoinductive agent with a systemically administered antibody that promotes bone formation can enhance bone repair and has potential as a therapeutic regimen in humans.

Management of complications of periarticular fractures of the distal interphalangeal, proximal interphalangeal, metacarpophalangeal, and carpometacarpal joints.

Fractures involving the bones of the hand are among the most common injuries in the United States. A significant portion of these fractures are periarticular. Although the great majority of these fractures are treated successfully by nonoperative means, complications arise. We present a comprehensive review of prevention and management of complications of periarticular fractures of the distal interphalangeal, proximal interphalangeal, metacarpophalangeal, and carpometacarpal joints.

Combination therapy with PTH and DBM cannot heal a critical sized murine femoral defect.

Orthopaedic surgeons continue to search for cost-effective bone graft substitutes to enhance bone repair. Teriparatide (PTH 1-34) and demineralized bone matrix (DBM) have been used in patients to promote bone healing. We evaluated the efficacy of PTH and DBM in healing a critical sized femoral defect in three lineage-specific transgenic mice expressing Col3.6GFPtopaz (pre-osteoblastic marker), Col2.3GFPemerald (osteoblastic marker) and α-SMA-Cherry (pericyte/myofibroblast marker). Mid-diaphyseal defects measuring 2 mm in length were created in the central 1/3 of mice femora using a circular saw and stabilized with an alveolar distractor device and cerclage wires. Three groups were evaluated: Group I, PTH 30 µg/kg injection daily, Group II, PTH 30 µg/kg injection daily + DBM, and Group III, DBM + 30µL saline injection. PTH was given for 28 days or until the time of sacrifice. Animals were sacrificed at 7, 14, 28, and 56 days. Radiographs at the time of sacrifice were evaluated using a 5-point scaled scoring system. Radiographs showed a lack of healing across all treatment groups at all time points: Group I, 1.57 +/- 0.68; Group II, 3.00 +/- 1.29; and Group III, 2.90 +/- 1.03. Bone formation in the defect as measured by radiographic healing score was significantly better at 56 days in Groups II (p = 0.01) and III (p < 0.01) compared to Group I. Across all treatment groups and time points the defects were largely absent of osteoprogenitor cells based on gross observation of frozen histology and quantitation of cellular based histomorphometric parameters. Quantitation of frozen histologic slides showed a limited osteoprogenitor response to PTH and DBM. Our results suggest that the anabolic agent teriparatide is unable to induce healing in a critical sized mouse femoral defect when given alone or in combination with the DBM preparation we used as a local bone graft substitute.

Evaluation of osteogenic cell differentiation in response to bone morphogenetic protein or demineralized bone matrix in a critical sized defect model using GFP reporter mice.

We evaluated the osteoprogenitor response to rhBMP-2 and DBM in a transgenic mouse critical sized defect. The mice expressed Col3.6GFPtopaz (a pre-osteoblastic marker), Col2.3GFPemerald (an osteoblastic marker) and α-smooth muscle actin (α-SMA-Cherry, a pericyte/myofibroblast marker). We assessed defect healing at various time points using radiographs, frozen, and conventional histologic analyses. GFP signal in regions of interest corresponding to the areas of new bone formation was quantified using a novel computer assisted algorithm. All defects treated with rhBMP-2 healed. In contrast, the majority of the defects in the DBM (27/30) and control (28/30) groups did not heal. Quantitation of pre-osteoblasts demonstrated a maximal response (% GFP + cells/TV) in the Col3.6GFPtopaz mice at day 7 (7.2% ± 6.0, p < 0.05 compared to days 14, 21, 28, and 56). The maximal response of the Col2.3GFP cells was seen at days 14 (8.04% ± 5.0) and 21 (8.31% ± 4.32), p < 0.05. In contrast, DBM and control groups showed a limited osteogenic response at all time points. In conclusion, we demonstrated that the BMP and DBM induce vastly different osteogenic responses which should influence their clinical application as bone graft substitutes.

Advances in wrist arthroscopy.

Since its introduction more than three decades ago, wrist arthroscopy has continually evolved. The procedure has a wide list of indications, including diagnostic and management applications. The scope of practice for the wrist arthroscopic surgeon includes management of triangulofibrocartilage complex pathology, evaluation and management of carpal instability, assistance in fracture reduction of the radius and scaphoid, treatment of trapeziometacarpal synovitis and arthritis, distal ulnar and carpal bone excisions, and salvage procedures. In addition, innovations such as new portals and smaller arthroscopes have expanded the applications of wrist arthroscopy.

Sternoclavicular joint reconstruction--a systematic review.

BACKGROUND: Dislocation of the sternoclavicular joint is a rare injury that has a low incidence of signifcant long-term symptoms. Surgical reconstruction of the joint is indicated in patients with symptomatic, chronic anterior instability or with irreducible or recurrent posterior instability. There have been many reported techniques for stabilization of the joint, but few investigators have reported more than several cases. The ideal reconstruction has not been identifed. PURPOSE: The purpose of this investigation was to perform a systematic review of the available literature with the objective of identifying one technique of sternoclavicular reconstruction that could be recommended. METHODS: A systematic review of literature pertaining to treatment of sternoclavicular joint injuries was performed, focusing on clinical reports with at least six patients and 1 year of follow-up. We also reviewed biomechanical reports pertaining to sternoclavicular reconstruction. RESULTS: Six clinical reports and two biomechanical studies were identifed that met our inclusion criteria. Treatments described in the clinical reports included conservative treatment with a sling, repair of the joint capsule with provisional stabilization, and joint reconstruction with local tissue or graft tissue. One biomechanical study compared the strength of three reconstruction techniques. CONCLUSION: Reconstruction with tendon tissue woven in a figure-of-eight pattern through drill holes in the manubrium and clavicle is stronger than reconstructions with local tissue. The review of clinical reports suggests excellent outcomes with this technique, and it is recommended in cases of chronic instability. In cases of acute instability requiring open reduction or inability to maintain a reduction in a posterior dislocation, there is evidence that repair of the joint capsule is suffcient surgical treatment.

Prediction of hypocalcemia after using 1- to 6-hour postoperative parathyroid hormone and calcium levels: an analysis of pooled individual patient data from 3 observational studies.

BACKGROUND: Parathyroid hormone (PTH) levels up to 6 hours postthyroidectomy have been shown to have excellent predictive power in determining hypocalcemia. In this study, we investigate the usefulness of combining calcium and PTH to increase the predictive power. METHODS: Individual patient data were obtained from 3 studies (152 patients) that fulfilled our criteria (using PTH assay within hours postthyroidectomy to predict symptomatic hypocalcemia). RESULTS: Changes in combined PTH and calcium threshold levels checked 1 to 6 hours after thyroidectomy were excellent in predicting postoperative hypocalcemia. A decrease in PTH of 60%, coupled with a simultaneous decrease in calcium of 10%, 5 to 6 hours postoperatively resulted in a sensitivity and specificity of 100%. However, combined PTH and calcium threshold changes were not significantly better than using PTH threshold changes alone. CONCLUSIONS: Threshold changes in serum calcium and PTH, checked hours after surgery, can be used together to accurately predict whether a patient will become hypocalcemic after thyroidectomy.