Sam Akhavan

Technique for Creating the Anterior Cruciate Ligament Femoral Socket: Optimizing Femoral Footprint Anatomic Restoration Using Outside-in Drilling

PURPOSEnThe purpose of this study was to investigate and optimize anterior cruciate ligament (ACL) femoral outside-in drilling technique with a goal of anatomic restoration of the footprint morphologic length, width, area, and angular orientation.nnnMETHODSnEx vivo, computer navigation was used to create virtual 3-dimensional maps of femoral bone tunnels for ACL drill guide pin insertion paths on small, medium, and large models of averaged femora considering various pin insertion angles to the femur. We then determined which pin insertion angle resulted in an ACL femoral footprint optimally matching normal human anatomic length, width, area, and angular orientation of the footprint long axis.nnnRESULTSnDuring outside-in drilling of the ACL femoral socket, a guide pin entrance angle of 60° to a line perpendicular to the femoral anatomic axis, combined with a guide pin entrance angle of 20° to the transepicondylar axis, results in the closest approximation of the gold standard of normal anatomic morphology of the human knee ACL femoral footprint length, width, area, and angular orientation.nnnCONCLUSIONSnDuring outside-in drilling of the ACL femoral socket, a guide pin entrance angle of 60° to a line perpendicular to the femoral anatomic axis, combined with a guide pin entrance angle of 20° to the transepicondylar axis, results in optimal reconstruction of the normal human anatomic ACL femoral footprint length, width, area, and angular orientation.nnnCLINICAL RELEVANCEnWe describe arthroscopic landmarks for anatomic ACL femoral socket creation that may be considered by practicing arthroscopic surgeons in the operating room, without open dissection or fluoroscopy and unaffected by type of drill guide or variations in the thickness of the femoral soft-tissue envelope.

Quadrupled Hamstring Graft Strength as a Function of Clinical Sizing

PURPOSEnThis study sought to compare the strength of quadrupled hamstring tendon (QHT) grafts of 6 to 9.5xa0mm in clinical diameter with that of 10-mm bone-patellar tendon-bone (BPTB) grafts.nnnMETHODSnTwenty cadaveric semitendinosus and gracilis tendons were combined into QHT grafts. These were sized using a standard graft-sizing device and an area micrometer, yielding grafts ranging from 6 to 9.5xa0mm in diameter. The grafts were tested to failure. Five 10-mm BPTB grafts were also sized and tested.nnnRESULTSnClinical sizing did predict the strength of the graft but not profoundly. As a material alone, without consideration of fixation in bone tunnels, QHT grafts were stronger than BPTB grafts. Graft strength decreased with size, but a linear relation between strength and diameter (r(2)xa0= 0.715, P < .001) was found to be as good as the expected quadratic fit (r(2)xa0= 0.709). Compared with BPTB grafts, even the smallest QHT grafts (diameter <6.5xa0mm) were still significantly stronger than 10-mm BPTB grafts (Pxa0= .004). The elastic moduli of the QHT and BPTB grafts were 761 ± 187xa0MPa and 615 ± 403xa0MPa, respectively; elongations at failure were 12.0% ± 2.0% and 7.5% ±xa01.6%, respectively; and failure stresses were 105 ± 18xa0MPa and 50 ± 14xa0MPa, respectively.nnnCONCLUSIONSnThis work shows that a clinical size of QHT grafts of 6xa0mm in diameter is not a concern regarding the strength itself. For a possible lower-end prediction of acceptable size, assuming that a gracilis-semitendinosus graft would have only the stress of the weakest measured QHT graft of 88xa0MPa, a graft of 5.5xa0mm in diameter would suffice, having more strength in newtons than the average patellar tendon.nnnCLINICAL RELEVANCEnClinically sized QHT grafts have a higher failure strength than 10-mm patellar tendon grafts. Therefore the strength of the graft cannot account for the higher clinical failure rates of smaller hamstring grafts in active patients in clinical studies.

An Algorithm for Diagnosing and Treating Primary and Recurrent Patellar Instability

Major anatomic risk factors for recurrent patellar instability include trochlear dysplasia, patella alta, a lateralized tibial tuberosity, and medial patellofemoral ligament insufficiency.Acute first-time patellar dislocation may be treated nonoperatively in the absence of osteochondral injury.Recurrent patellar instability often requires medial patellofemoral ligament reconstruction, with osseous procedures reserved for patients with substantial underlying anatomic abnormalities.Surgical treatment of patellar instability is complex and should be individualized to address the needs of each patient.

Posterior Shoulder Instability in Athletes

Posterior instability represents up to 10% of all cases of shoulder instability1. In athletes, posterior instability can result from a single traumatic injury, repetitive microtrauma, or, rarely, atraumatic instability. The demands on the athlete’s shoulder, especially in contact or overhead throwing sports, can be dramatic, and, as a result, the managing orthopaedic surgeon must understand the complexities of such an injury complex. Participation in contact sports may result in an increased risk for the development of traumatic posterior instability. In overhead athletes, posterior instability can result from repetitive microtrauma sustained from an early age, which can be further exacerbated with the increase in year-round play.nn### Static StabilizersnnThe static stabilizers of the glenohumeral joint include the glenoid and the humeral head, the capsulolabral complex, the articular surface, and the glenohumeral ligaments. Anatomic alterations of the retroversion of the osseous and chondrolabral portions of the glenoid have been shown to be associated with posterior shoulder instability2. Cadaveric studies of …

Interobserver and Intraobserver Reliability of an MRI-Based Classification System for Injuries to the Ulnar Collateral Ligament:

Background: Despite improvements in understanding biomechanics and surgical options for ulnar collateral ligament (UCL) tears, there remains a need for a reliable classification of UCL tears that has the potential to guide clinical decision making. Purpose: To assess the intra- and interobserver reliability of the newly proposed magnetic resonance imaging (MRI)–based classification for UCL tears. Secondary objectives included assessing the effect of additional views, discrimination between distal and nondistal tears, and correlation of imaging reads with intraoperative findings of the UCL. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Nine fellowship-trained specialists from 7 institutions independently completed 4 surveys consisting of 60 elbow MRI scans with UCL tears using a newly proposed 6-stage classification system. The first and third surveys contained 60 coronal images, while the second and fourth contained the same images with coronal and axial views presented in a random order to assess intraobserver variability via the weighted kappa value and the effect of additional imaging views. Weighted kappa values were also calculated for each of the 4 surveys to acquire interobserver reliability. Reliability analysis was repeated through a 2-group classification analysis for distal and nondistal tears. Observer readings were compared with intraoperative UCL findings. Results: For the newly proposed 6-stage MRI-based classification, intra- and interobserver reliability demonstrated near perfect and substantial agreement, respectively. These values increased only when substratified into the 2-group distal and nondistal tear classification (P < .05). The additional axial view did not statistically improve the agreement within and among readers. When compared with intraoperative findings from 30 elbows, observer readings were accurate for tear grade (partial and complete), proximal location, and distal location but not midsubstance tears. Conclusion: The newly proposed 6-stage MRI-based classification utilizing grade and location of the injury had substantial to near perfect agreement among and within fellowship-trained observers.

Quantification of Long Head of the Biceps Tendon Motion After Loop ‘N’ Tack Suprapectoral Biceps Tenodesis

Objectives: Lesions of the long head of the biceps are one of the most frequent causes of shoulder pain, and they can be successfully treated with biceps tenotomy or tenodesis. The advantage of a biceps tenodesis is avoiding the potential development of a cosmetic deformity (“Popeye sign”) or cramping muscle pain that can remain after tenotomy. Proponents of a subpectoral tenodesis believe that “groove pain” may remain a problem after suprapectoral tenodesis due to persistent motion of the biceps tendon within the bicipital groove. The objective of this study was to evaluate the motion of the biceps tendon within the bicipital groove before and after a suprapectoral tenodesis performed using the Loop ‘N’ Tack technique. Our hypothesis was that there would be minimal to no motion of the biceps tendon within the bicipital groove after the tenodesis. Methods: Six fresh-frozen cadaveric arms were obtained and dissected to expose the long head of biceps tendon and the bicipital groove from the transverse humeral ligament to the pectoralis major insertion. The scapula and ulna were affixed with inclinometers to measure motion in multiple planes. The biceps tendon and bicipital groove were marked with fiducials, which were tracked by two cameras focused on this region. The shoulder and elbow were taken through a full range of motion including scapular abduction, forward flexion, extension, internal rotation, and external rotation and elbow flexion and extension with a supinated, neutral, or pronated forearm. The translation of the biceps tendon was quantified as a function of scapular or forearm motion in each plane. A suprapectoral biceps tenodesis was then performed using the Loop ‘N’ Tack technique. The scapula and forearm were taken through the same motions, and the translation of the biceps tendon was quantified. A paired t-test was performed for each motion to determine if maximum biceps tendon translation in the bicipital groove was a function of tendon condition (native vs post-tenodesis). Results: There was minimal translation of the biceps tendon during elbow flexion and extension, both before and after tenodesis. There was significant translation of the biceps tendon in all planes of scapular motion in the native state, and the largest amount of translation was 20.73mm +/- 8.21mm during shoulder flexion and extension (Table 1). The translation of the biceps tendon after tenodesis was significantly reduced in every plane of scapular motion compared to the native state (p = 0.01 or p < 0.01 in all planes of motion). The largest amount of translation in any plane after tenodesis was 1.57mm +/- 0.98mm, which occured during shoulder flexion and extension (Table 1). Conclusion: In the native state, the translation of the biceps tendon within the bicipital groove ranges from 5.14mm - 20.73mm with scapular motion. There is statistically significant reduction in translation of the biceps tendon in all planes of scapular motion after the Loop ‘N’ Tack tenodesis (Figure 1), with a maximum translation of only 1.57mm. These data suggest that motion of the biceps tendon within the bicipital groove is essentially eliminated and should not be a cause of persistent pain. The Loop ‘N’ Tack biceps tenodesis is a simple, all-arthroscopic technique for patients with proximal biceps pathology. It is a viable alternative to subpectoral tenodesis, essentially eliminating all motion of the biceps tendon within the bicipital groove, and it should not lead to persistent “groove pain”. Table 1. Native Post-Tenodesis Results Average (mm) S.D. (mm) Average (mm) S.D. (mm) P-Value Elbow Flexion: Supination 1.85 1.66 0.56 0.37 0.15 Elbow Flexion: Neutral 1.73 1.43 0.83 0.64 0.30 Elbow Flexion: Pronation 3.03 1.55 0.72 0.24 0.01 Glenohumeral: Internal/External Rot. 9.37 1.70 1.32 0.78 <0.01 Glenohumeral: Flexion/Extension 20.73 8.21 1.57 0.98 <0.01 Glenohumeral: Full Flexion 10.32 2.60 0.75 0.47 <0.01 Glenohumeral: Abduction 5.14 2.67 1.26 1.17 0.01

Mid-term Outcomes of the Subchondroplasty Procedure for Patients with Osteoarthritis and Bone Marrow Edema:

Objectives: Bone marrow edema (BME) is a negative prognostic factor for patients with knee osteoarthritis (KOA). BME is strongly associated with pain, decreased function, structural deterioration and rapid progression to total knee arthroplasty (TKA). Subchondroplasty (SCP) (Knee Creations, Zimmer, Warsaw, IN) directly addresses BME in the setting of KOA by injecting calcium phosphate cement into the area of BME. The objective of this research was to show clinical results of the SCP procedure. Methods: A retrospective chart review with follow-up questionnaire was conducted on SCP patients in short-term and midterm (>2 years). All patients failed conservative measures and were candidates for TKA. The questionnaire addressed symptoms before and after SCP, further interventions, the perception of and willingness to undergo SCP again. Results: 133 of 143 subchondroplasty patients responded. The average patient was 57 years old (38-84 years) and 47% male. The average follow-up for short-term patients was 14.6 (4-22) months and for mid-term patients was 32.1 (24-43) months. Pain score decreased from 8.3 pre-op to 3.4 post-op in both groups. 35% in the short-term group required injections, increasing to 41% in the mid-term. The short-term group demonstrated satisfaction of 8.3 out of 10, with 82% willing to undergo SCP again and 89% recommending SCP. In the mid-term group, satisfaction increased to 8.5 with 95% willing to undergo SCP again and 96% recommending the procedure. In all, 32 patients (25%) progressed to TKA (Figure 1) at an average of 17.8 months, with 22 (69%) of these occurring before 2 years. Conclusion: SCP is an effective and well received treatment for patients with KOA and BME. In patients who failed conservative measures and were considering TKA, excellent results are seen at 2.5 years follow-up with only 25% of patients requiring TKA. Of all patients not requiring TKA, 93% would undergo SCP again and 98% would recommend it. Table l. Short and Mid-term Results of the Snhcliondroplasty Procedure Preop Short-term Mid-term All-Comers Patients 128 87 84 128 Avg, f/u 14.6 months 32.1 months 23.1 Pain Score 8.3 3.4 3.4 3.4 TKA 22 (25%) 10 (12%) 32 (25%) Avg, time to TKA 11.5 months 30.7 months 17.8 months Injections 23 (35%) 30(41%) 38 (40%) Satisfaction 8.3 8.5 8.4 Undergo Again 82% 95% 93% Recommend 89% 96% 98%

Short-Term Outcomes of the Subchondroplasty Procedure for the Treatment of Bone Marrow Edema Lesions in Patients with Knee Osteoarthritis

Objectives: To determine the short-term outcomes, effectiveness and perception of the subchondroplasty (SCP) procedure in patients with radiographic evidence of bone marrow edema (BME) in the setting of knee osteoarthritis (OA). Methods: A retrospective chart review in conjunction with a follow-up questionnaire was conducted on fifty patients with radiographic evidence of BME lesions who underwent the SCP procedure performed at a single academic medical institution. All patients failed prior conservative measures, including medications, injections, physical therapy, and bracing. The questionnaire focused on symptoms before and after the procedure, the perception of the procedure, any other interventions performed after the procedure, and willingness to undergo SCP again. Results: The average patient age was 55 years (range 36-82 years) and 53.2% of patients were male. The average follow-up period was 14.6 months (range 12.9-25.1 months). Preliminary data from 50 patients demonstrated an average 4.7 point improvement in pain on a 10 point visual analog scale (pre-SCP 8.3, post-SCP 3.6). Eighty-eight percent (44 of 50) of patients experienced improvement in their pain and 72% (36 of 50) experienced improvement in pain-free walking distance. Forty-eight percent (24 of 50) of patients required additional interventions: eighteen received cortisone or hyaluronic acid injections, two required serial aspirations, and four went on to total knee arthroplasty. The average satisfaction level was 7.8 on a 10 point scale. Seventy-eight percent (39 of 50) of patients stated they would undergo SCP again and 86% (43 of 50) would recommend the procedure to a friend or family member. Conclusion: SCP is an effective treatment modality in the management of patients with knee OA and BME lesions. The goal of the procedure is to provide enduring pain relief caused by BME, hopefully delaying the need for TKA in this select patient population. Future studies are necessary to evaluate the long-term outcomes of SCP.

Finite Element Analysis of the Ulnar Tunnel in Ulnar Collateral Ligament Reconstruction

The ulnar collateral ligament (UCL) of the elbow originates on the medial epicondyle of the humerus and inserts on the sublime tubercle of the proximal ulna. This ligament is classically composed of three distinct structures: the anterior bundle, the posterior bundle, and the transverse bundle. Of these three, the anterior bundle has been shown to be the primary stabilizer to valgus load between 20° and 120° of flexion [1]. Injuries to the anterior bundle of the UCL are commonly seen in baseball pitchers, where the valgus load on the elbow during the throwing motion approaches the failure load of the ligament [2].Copyright