Alexander R. Vap

Effect of end-stage hip, knee, and ankle osteoarthritis on walking mechanics

This study tested the hypothesis that the presence of isolated ankle (A-OA; N=30), knee (K-OA; N=20), or hip (H-OA; N=30) osteoarthritis (OA) compared to asymptomatic controls (N=15) would lead to mechanical changes in the affected joint but also in all other lower limb joints and gait overall. Stride length, stance and swing times, as well as joint angles and moments at the hip, knee, and ankle were derived from 3-D kinematic and kinetic data collected from seven self-selected speed walking trial. Values were compared across groups using a 1×4 ANCOVA, covarying for walking speed. With walking speed controlled, the results indicated a reduction in hip and knee extension and ankle plantar flexion in accordance with the joint affected. In addition, OA in one joint had strong effects on other joints. In both H-OA and K-OA groups the hip never passed into extension, and A-OA subjects significantly changed hip kinematics to compensate for lack of plantar flexion. Finally, OA in any joint led to lower peak vertical forces as well as extension and plantar flexion moments compared to controls. The presence of end-stage OA at various lower extremity joints results in compensatory gait mechanics that cause movement alterations throughout the lower extremity. This work reinforces our understanding of the complex interaction of joints of the lower limb and the importance of focusing on the mechanics of the entire lower limb when considering gait disability and potential interventions in patients with isolated OA.

A Comprehensive Reanalysis of the Distal Iliotibial Band: Quantitative Anatomy, Radiographic Markers, and Biomechanical Properties:

Background: The qualitative anatomy of the distal iliotibial band (ITB) has previously been described. However, a comprehensive characterization of the quantitative anatomic, radiographic, and biomechanical properties of the Kaplan fibers of the deep distal ITB has not yet been established. It is paramount to delineate these characteristics to fully understand the distal ITB’s contribution to rotational knee stability. Purpose/Hypothesis: There were 2 distinct purposes for this study: (1) to perform a quantitative anatomic and radiographic evaluation of the distal ITB’s attachment sites and their relationships to pertinent osseous and soft tissue landmarks, and (2) to quantify the biomechanical properties of the deep (Kaplan) fibers of the distal ITB. It was hypothesized that the distal ITB has definable parameters concerning its anatomic attachments and consistent relationships to surgically pertinent landmarks with correlating plain radiographic findings. In addition, it was hypothesized that the biomechanical properties of the Kaplan fibers would support their role as important restraints against internal rotation. Study Design: Descriptive laboratory study. Methods: Ten nonpaired, fresh-frozen human cadaveric knees (mean age, 61.1 years; range, 54-65 years) were dissected for anatomic and radiographic purposes. A coordinate measuring device quantified the attachment areas of the distal ITB to the distal femur, patella, and proximal tibia and their relationships to pertinent bony landmarks. A radiographic analysis was performed by inserting pins into the attachment sites of relevant anatomic structures to assess their location relative to pertinent bony landmarks with fluoroscopic guidance. A further biomechanical assessment of 10 cadaveric knees quantified the load to failure and stiffness of the Kaplan fibers’ insertion on the distal femur after a preconditioning protocol. Results: Two separate deep (Kaplan) fiber bundles were identified with attachments to 2 newly identified femoral bony prominences (ridges). The proximal and distal bundles inserted on the distal femur 53.6 mm (95% CI, 50.7-56.6 mm) and 31.4 mm (95% CI, 27.3-35.5 mm) proximal to the lateral epicondyle, respectively. The centers of the bundle insertions were 22.5 mm (95% CI, 19.1-25.9 mm) apart. The total insertion area of the distal ITB on the proximal tibia was 429.1 mm2 (95% CI, 349.2-509.1 mm2). A distinct capsulo-osseous layer of the distal ITB was also identified that was intimately related to the lateral knee capsule. Its origin was in close proximity to the lateral gastrocnemius tubercle, and it inserted on the proximal tibia at the lateral tibial tubercle between the fibular head and the Gerdy tubercle. Radiographic analysis supported the quantitative anatomic findings. The mean maximum load during pull-to-failure testing was 71.3 N (95% CI, 41.2-101.4 N) and 170.2 N (95% CI, 123.6-216.8 N) for the proximal and distal Kaplan bundles, respectively. Conclusion: The most important finding of this study was that 2 distinct deep bundles (Kaplan fibers) of the distal ITB were identified. Each bundle of the deep layer of the ITB was associated with a newly identified distinct bony ridge. Radiographic analysis confirmed the measurements previously recorded and established reproducible landmarks for the newly described structures. Biomechanical testing revealed that the Kaplan fibers had a strong attachment to the distal femur, thereby supporting a role in rotational knee stability. Clinical Relevance: The identification of 2 distinct deep fiber (Kaplan) attachments clarifies the function of the ITB more definitively. The results also support the role of the ITB in rotatory knee stability because of the fibers’ vectors and their identified maximum loads. These findings provide the anatomic and biomechanical foundation needed for the development of reconstruction or repair techniques to anatomically address these deficiencies in knee ligament injuries.

The Role of the Peripheral Passive Rotation Stabilizers of the Knee With Intact Collateral and Cruciate Ligaments: A Biomechanical Study

Background: A subset of patients have clinical internal and/or external knee rotational instability despite no apparent injury to the cruciate or collateral ligaments. Purpose/Hypothesis: The purpose of this study was to assess the effect of sequentially cutting the posterolateral, anterolateral, posteromedial, and anteromedial structures of the knee on rotational stability in the setting of intact cruciate and collateral ligaments. It was hypothesized that cutting of the iliotibial band (ITB), anterolateral ligament and lateral capsule (ALL/LC), posterior oblique ligament (POL), and posteromedial capsule (PMC) would significantly increase internal rotation, while sectioning of the anteromedial capsule (AMC) and the popliteus tendon and popliteofibular ligament (PLT/PFL) would lead to a significant increase in external knee rotation. Study Design: Controlled laboratory study. Methods: Ten pairs (N = 20) of cadaveric knees were assigned to 2 sequential cutting groups (group 1: posterolateral-to-posteromedial [PL → PM] and group 2: posteromedial-to-posterolateral [PM → PL]). Specimens were subjected to applied 5-N·m internal and external rotation torques at knee flexion angles of 0°, 30°, 60°, and 90° while intact and after each cut state. Rotational changes were measured and compared with the intact and previous cut states. Results: Sectioning of the ITB significantly increased internal rotation at 60° and 90° by 5.4° and 6.2° in group 1 (PL → PM) and 3.5° and 3.8° in group 2 (PM → PL). PLT/PFL complex sectioning significantly increased external rotation at 60° and 90° by 2.7° and 2.9° in group 1 (PL → PM). At 60° and 90° in group 2 (PM → PL), ALL/LC sectioning produced significant increases in internal rotation of 3.1° and 3.5°, respectively. In group 2 (PM → PL), POL sectioning produced a significant increase in internal rotation of 2.0° at 0°. AMC sectioning significantly increased external rotation at 30° to 90° of flexion with a magnitude of change of <1° in both groups 1 (PL → PM) and 2 (PM → PL). Conclusion: Collectively, the anterolateral corner structures provided primary internal rotation control of the knee from 60° to 90° of knee flexion in knees with intact cruciate and collateral ligaments. The ITB was the most significant primary stabilizer of internal rotation. The POL had a primary role for internal rotational stability at full extension. The PLT/PFL complex was a primary stabilizer for external rotation of the knee at 60° and 90°. Clinical Relevance: This study delineates the primary and secondary roles of the ITB, ALL/LC, POL, and PLT/PFL to rotatory stability of the knee and provides new information to understand knee rotational instabilities.

Gender Differences in Plantar Loading During an Unanticipated Side Cut on FieldTurf.

Objective:To determine whether force–time integral (FTI) and maximum force (MF) are significantly different between genders when performing an unanticipated side cut on FieldTurf. Design:Thirty-two collegiate athletes (16 men and 16 women) completed 12 unanticipated cutting trials, while plantar pressure data were recorded using Pedar-X insoles. Setting:Controlled Laboratory Study. Participants:Division I cleated sport athletes with no previous foot and ankle surgery, no history of lower extremity injury in the past 6 months, and no history of metatarsal stress fracture. Interventions:None. Main Outcome Measures:Maximum force and the FTI in the total foot, medial midfoot (MMF), lateral midfoot (LMF), medial forefoot (MFF), middle forefoot (MiddFF), and the lateral forefoot (LFF). Results:Males had a greater FTI beneath the entire foot (TF) (P < 0.001). Females had a significantly higher MF beneath the LMF (P = 0.001), MiddFF (P < 0.001), and LFF (P = 0.001). Males had a significantly greater MF beneath the MMF (P = 0.003) and greater FTI beneath the MMF (P < 0.001) and MFF (P = 0.002). Conclusions:Significant differences in plantar loading exist between genders with males demonstrating increased loading beneath the TF in comparison with females. Females had overall greater loading on the lateral column, whereas males had greater loading on the medial column of the foot. Clinical Relevance:The results of this study indicate that plantar loading is different between genders; therefore, altering cleated footwear to be gender specific may result in more optimal foot loading patterns. Optimizing cleated shoe design could decrease the risk for metatarsal stress fractures.

Endoscopic Trochanteric Bursectomy and Iliotibial Band Release for Persistent Trochanteric Bursitis

Lateral hip pain associated with trochanteric bursitis is a common orthopedic condition, and can be debilitating in chronic or recalcitrant situations. Conservative management is the most common initial treatment and often results in resolution of symptoms and improved patient outcomes. These modalities include rest, activity modification, physical therapy, anti-inflammatory medication, or corticosteroid injections. However, there is a subset of patients in which symptoms persist despite exhaustive conservative modalities. For these patients, trochanteric bursectomy is a surgical option to address persistent pathology. Previous literature indicates that both open and arthroscopic surgical techniques can be used to address the inflamed bursa and results in good patient outcomes. However, recent advances in hip arthroscopy have allowed for improvements in minimally invasive techniques to address intracapsular and extracapsular pathology of the hip, including recalcitrant trochanteric bursitis. The purpose of this manuscript is to describe our technique for a minimally invasive arthroscopic trochanteric bursectomy.

Internal and External Rotation Stabilizers of the Knee with Intact Cruciate and Collateral Ligaments: A Biomechanical Study

Objectives: The purpose of this study was to assess the effect of sequentially cutting the posterolateral, anterolateral, posteromedial and anteromedial structures of the knee on rotational kinematics in the setting of intact cruciate and collateral ligaments. It was hypothesized that cutting of the iliotibial band (ITB), anterolateral ligament and lateral capsule (ALL/LC), the posterior oblique ligament (POL), and the posteromedial capsule (PMC) would significantly increase internal rotation and that the anteromedial capsule (AMC), and the popliteus tendon and popliteofibular ligament (PLT/PFL) when sectioned would lead to a significant increase in external rotation of the knee. Methods: Ten pairs (n = 20) of cadaveric knees were assigned to two sequential cutting groups (posterolateral-to-posteromedial and posteromedial-to-posterolateral). Specimen were subjected to 5 N-m of internal and external rotation torque at knee flexion angles 0° through 90° in the intact and after each cut state. Rotational changes were measured and compared to the intact and previous states following each cut. Results: Sectioning of the ITB significantly increased internal rotation at 60° and 90° by 5.4° and 6.2[[Unsupported Character - Codename ]]°, respectively (after ALL/LC cut) and 3.5° and 3.8° (prior to ALL/LC cut) (Figure 1). At 60° and 90°, section of the ALL/LC produced significant increases in internal rotation of 3.1[[Unsupported Character - Codename ]]° and 3.5°, respectively (after ITB cut) and of 0.5° (prior to ITB cut) (Figure 1). At 0°, section of the POL produced significant increases in internal rotation of 2.0° (ITB intact) and 1.8° (after ITB cut) (Figure 1). Sectioning the PLT/PFL complex significantly increased external rotation at 60° and 90° by 2.7° and 2.9°, respectively (prior to sectioning medial structures) and 2.2° and 2.7[[Unsupported Character - Codename ]]°, respectively (after sectioning medial structures) (Figure 2). Sectioning the AMC produced significant increases in external rotation at 30°- 90° of flexion, however the magnitude of change was < 1° (Figure 2). Figure 1. Changes in internal rotation from the intact state during a 5 N-m internal rotation torque when sequentially cutting structures from lateral to medial (above) and medial to lateral (below). Figure 2. Changes in external rotation from the intact state during a 5 N-m external rotation torque when sequentially cutting structures from lateral to medial (above) and medial to lateral (below). Conclusion: Collectively the anterolateral corner structures had a primary role in internal rotational control of the knee from 60° to 90° of knee flexion. The ITB was the most significant primary stabilizer for internal rotation in ACL intact knees. The POL contributed to internal rotational control at full extension, while the PLT/PFL complex controlled external rotation of the knee at higher flexion angles (60° and 90°). Internal rotation control of the knee has been mainly attributed to the cruciate and collateral ligaments. This study delineates the primary and secondary roles of the ITB, the ALL/LC, POL and PLT/PFL to rotatory stability of the knee. As such, it provides new information about the understanding of rotational instabilities of the knee.

Open Subpectoral Biceps Tenodesis for Isolated Biceps Reflection Pulley Lesions: Minimum 2-year Outcomes in a Young Patient Population

Objectives: Biceps Reflection Pulley (BRP) lesion is a common generator of anterior shoulder pain and cause of biceps tendon instability. The purposes of this study were (1) to investigate if patients younger than 50 years had improved functional outcomes following open subpectoral biceps tenodesis (BT) for treatment of an isolated BRP lesion with a minimum follow-up of 2-years, and (2) to determine whether a correlation exists between patient age and outcomes scores. It was hypothesized that subpectoral BT would result in reduced pain, improved functional outcomes, and a high return-to-activity rate and that there would be no association between patient age and outcomes scores. Methods: This was an IRB-approved study with retrospective review of prospectively-collected data. All patients who had arthroscopically confirmed isolated BRP lesion treated with open subpectoral biceps tenodesis were at least 2 years out from surgery were included in the study. Patients with additional surgery on the index shoulder were excluded from the study. ASES (pain and function), QuickDASH, and SF-12 scores were collected pre- and postoperatively. Postoperative satisfaction (10-point scale) was also collected. The pre- and postoperative scores of each patient were compared with a Wilcoxon-test, and association between patient age and outcomes scores were investigated with a Spearman correlation test. Further, patient return-to-activity was evaluated by questionnaire. Failure was defined as revision surgery of the biceps tenodesis. Results: 14 shoulders in 14 patients (6 male, 8 female) with a mean age of 37 ± 8.9 years met the inclusion criteria. Minimum 2-year outcomes data were available for 13 (93%) shoulders. The mean follow-up time was 3.6 ± 1.3 years. There were significant improvements postoperatively for all outcome scores (p<0.05, see table 1) and no patients underwent revision surgery of the biceps tenodesis. There was no correlation between age and outcomes scores (p>0.05). Overall, median patient satisfaction was 9 out of 10 (range 3-10). Of 14 patients who answered the “return-to-activity” questions, 5 patients () reported return to activity with no modification; 9 patients reported return to activity with modifications. The 5 patients who returned to activity with no modification had significantly less time from initial injury/onset of symptoms until surgery in comparison to the 9 patients who modified their activity (p <0.05, see table 1). Conclusion: At minimum 2-year follow-up, patients with symptomatic isolated BRP lesions can expect excellent clinical outcomes, high satisfaction, and a high return-to-activity rate with little postoperative pain if treated with an open subpectoral BT close to the time of their initial injury/onset of symptoms. No differences in outcomes were observed upon patient age. Table 1: Pre- and postoperative outcomes scores and p-values. Values are expressed as median (range) unless otherwise indicated. Test Preoperative Postoperative p-value ASES Total 62 (33-80) 97 (28-100) 0.017 ASES Func 29 (13-38) 45 (18-50) 0.005 ASES pain 35 (15-50) 50 (10-50) 0.034 QuickDash 39(11-70) 7(0-54) 0.002 SF-12 PCS 43 (22-58) 56 (39-59) 0.003 Satisfaction - 9 (3-10) - Return to activity – Patients (Percent) Time until surgery (days) - 5 (36%) no modifications 215 (49-414)9 (64%) w/ modications 1375 (79-7472) P = 0.028

Glenoid Erosion Leading to Contact with Retained Metallic Suture Anchors: Bilateral Metallosis After Bilateral Shoulder Hemiarthroplasty

Case: Hemiarthroplasty of the shoulder is commonly indicated for younger patients with osteoarthritis who desire to continue recreational and employment activities. In patients who have undergone prior shoulder surgery, metallic suture anchors may be present in the glenoid. We present a case of bilateral shoulder metallosis following bilateral resurfacing hemiarthroplasty for arthropathy in the setting of previous shoulder instability; the prostheses caused eventual glenoid erosion, leading to contact with the retained metal anchors. Conclusion: Because glenoid erosion is a common complication after shoulder hemiarthroplasty, patients with retained metal anchors are at risk for secondary metallosis due to medial protrusion of the prosthesis in the glenoid, with subsequent erosion of the metal anchors.

Concomitant Reverse Hill-Sachs Lesion and Posterior Humeral Avulsion of the Glenohumeral Ligament: Treatment With Fresh Talus Osteochondral Allograft and Arthroscopic Posterior Humeral Avulsion of the Glenohumeral Ligament and Labrum Repair

Chronic posterior glenohumeral joint instability can be a challenging clinical entity for patients and surgeons alike. In the setting of a posterior dislocation, a large anterior humeral impaction injury (reverse Hill-Sachs [HS]) may occur, leading to engagement of the humerus with the posterior glenoid bone, especially during internal rotation of the joint. A reverse HS is especially debilitating because of the significant portion of affected humeral head cartilage, and is made worse in the setting of ligamentous disruption such as a posterior humeral avulsion of the glenohumeral ligament (HAGL) lesions. Although several nonanatomic procedures to address these defects have been previously described, recent interest in anatomic reconstructions capable of restoring the cartilage surface of the humeral head has led to the use of bone grafts (autografts and allografts) to restore the articular contour of the humeral head in conjunction with anatomic repair of associated soft tissue injuries. We present our preferred technique for an anatomic repair of a posterior HAGL lesion in combination with reconstruction of an engaging reverse HS lesion using an unmatched hemitalar allograft.

Posterior Wall Blowout During Anterior Cruciate Ligament Reconstruction: Suspensory Cortical Fixation With a Screw and Washer Post

Posterior wall blowout can be a devastating intraoperative complication in anterior cruciate ligament reconstruction. This loss of osseous containment can cause difficulty with graft fixation and can potentially lead to early graft failure if unrecognized and left untreated. If cortical blowout occurs despite careful planning and proper surgical technique, a thorough knowledge of the local anatomy and surgical salvage options is paramount to ensure positive patient outcomes. This article highlights our preferred salvage technique using suspensory cortical fixation with a screw and washer construct.