Setting Of Recurrent Instability Research Articles

Bone loss in shoulder instability: putting it all together.

Glenohumeral bone loss is frequently observed in cases of recurrent anterior and posterior shoulder instability and represents a risk factor for failure of nonoperative treatment. Patients with suspected glenoid or humeral bone loss in the setting of recurrent instability should be evaluated with a thorough history and physical examination, as well as advanced imaging including computed tomography (CT) and/or magnetic resonance imaging (MRI). In cases of both anterior and posterior instability, the magnitude and location of bone loss should be determined, as well as the relationship between the glenoid track (GT) and any humeral defects. While the degree and pattern of osseous deficiency help guide treatment, patient-specific risk factors for recurrent instability must also be considered when determining patient management. Treatment options for subcritical anterior bone loss include labral repair and capsular plication, while more severe deficiency should prompt consideration of bony augmentation including coracoid transfer or free bone block procedures. Concomitant humeral lesions are treated according to the degree of engagement with the glenoid rim and may be addressed with soft tissue remplissage or bony augmentation procedures. While critical and subcritical thresholds of glenoid bone loss guide the management of anterior instability, such thresholds are less defined in the setting of posterior instability. Furthermore, current treatment algorithms are limited by a lack of long-term comparative studies. Future high-quality studies as well as possible modifications in indications and surgical technique are required to elucidate the optimal treatment of anterior, posterior, and bipolar glenohumeral bone loss in the setting of recurrent shoulder instability.

Anteromedialization Tibial Tubercle Osteotomy Improves Patellar Contact Forces: A Cadaveric Model of Patellofemoral Dysplasia

Background: Patellofemoral (PF) dysplasia is common in patients with recurrent patellar instability. Tibial tubercle osteotomy (TTO) is performed with goals of correcting patellar maltracking and redistributing contact forces across the PF joint. The biomechanical effects of TTO in the setting of PF dysplasia have not been quantified. Purpose/Hypothesis: To quantify patellar contact mechanics and kinematics after TTO in the setting of PF dysplasia. We hypothesized that a simulated anteromedialization (AMZ) TTO would improve PF contact mechanics as compared with a pure medialization TTO. Study Design: Controlled laboratory study. Methods: PF dysplasia with Dejour type D classification was simulated in 7 cadaveric knees by replacing the native patellar and trochlear surfaces with synthetic polymeric patellar and trochlear implants. On each specimen, a flat TTO was fixed in 3 distinct positions simulating a pathologic lateralized tubercle (pathologic condition), a medialized tubercle (Elmslie Trillat), and an AMZ tubercle. The sum of forces acting on the medial and lateral patellar facet and patellar kinematics was computed for each knee for each condition from 0° to 70° of flexion at 10° increments. Results: Relative to the pathologic condition, AMZ TTO decreased contact forces across the lateral facet (20°-50° and 70° of flexion). Relative to the pathologic condition, Elmslie Trillat TTO had no effect on contact forces on either compartment. Relative to the Elmslie Trillat TTO, the AMZ TTO had significantly decreased contact forces across the medial facet (at 40°, 60°, and 70° of flexion). No significant differences in joint kinematics occurred across any groups. Conclusion: Of all groups studied, AMZ TTO resulted in significantly decreased patellar contact forces in simulated dysplastic PF joints. AMZ may be considered in certain patients with PF dysplasia to avoid medial compartment PF chondral overload. Clinical Relevance: PF dysplasia is common in patients with recurrent patellar instability who warrant surgical intervention to prevent subsequent recurrence. Numerous interventions to treat this condition, including various TTOs, have been proposed without a clear consensus. This cadaveric biomechanical study demonstrates that AMZ TTO resulted in more favorable PF contact mechanics than Elmslie Trillat TTO in a model representing PF dysplasia. AMZ TTO may be considered for patients in the setting of recurrent instability with PF dysplasia to avoid cartilage overload on the medial compartment of the PF joint.

Increased superior translation following multiple simulated anterior dislocations of the shoulder.

Recurrent shoulder dislocations can result in kinematic changes of the glenohumeral joint. The number of prior shoulder dislocations may contribute to increased severity of capsulolabral lesions. The kinematics of the glenohumeral joint following multiple dislocations remain poorly understood. The purpose of this study was to assess the kinematics of the glenohumeral joint during anterior dislocations of the shoulder, and more specifically, altered translational motion following multiple dislocations. The kinematics of the glenohumeral joint were hypothesized to change and correlate with the number of dislocations. Eight fresh-frozen cadaveric shoulders were dissected free of all soft tissues except the glenohumeral capsule. Each joint was mounted in a robotic testing system. At 60 degrees of glenohumeral abduction, an internal and external rotational torque (1.1 Nm) were applied to the humerus, and the resulting joint kinematics were recorded. Anterior forces were applied to the humerus to anteriorly dislocate the shoulder and the resulting kinematics were recorded during each dislocation. Following each dislocation, the same rotational torque was applied to the humerus, and the resulting joint kinematics were also recorded. A repeated-measures analysis of variance (ANOVA) was used to compare the kinematics following each dislocation. During the 7th, 8th, 9th, and 10th dislocations, the humerus significantly translated superiorly compared with the shoulder during the 1st dislocation (p < 0.05). Following the 3rd, 4th, 5th, and 10th dislocations, the humeral head significantly translated superiorly compared with the shoulder following the 1st dislocation in the position of 60 degrees of abduction in response to external rotation torque (p < 0.05). Multiple anterior shoulder dislocations lead to abnormal translational kinematics and result in increased superior translation of the humerus. This may contribute to pathologic superior extension of capsulolabral injuries. Superior translation of the humerus with overhead motion in the setting of recurrent instability may also place the shoulder at risk for extension of the capsulolabral injuries.

Paper 72: How Much Glenoid Bone Loss Needs to be Restored with a Latarjet?

Objectives:Significant anterior glenoid bone loss in the setting of recurrent instability may warrant a coracoid transfer (Latarjet). However, the amount of glenoid width that must be restored with a Latarjet in order to reestablish glenohumeral stability has not been studied.We hypothesize that restoration of greater than 90% of glenoid width with a Latarjet will be necessary to restore glenohumeral stability. We also hypothesize that there will be significant increases in anterior humeral head translation when 90% or less of the native glenoid width is restored and that contact pressures on the coracoid graft will increase.Methods:Seven cadaveric specimens were prepared and mounted on an established shoulder simulator, which loads shoulder tendons through a system of pulleys and weights. A motion tracking system to record glenohumeral translations was placed on the scapula and humerus and registered based on a computed tomography (CT) scan. Contact pressures were mapped and recorded using a TekScan secured to the glenoid face and coracoid graft transfer (Figure 1). The humerus was placed in 90 degrees of humerothoracic abduction.Coracoid osteotomy was performed, and the coracoid graft was sized to a depth of 10mm. A lesser tuberosity osteotomy (LTO) was performed to allow accurate removal of glenoid bone. The amount of bone loss needed to re-establish 110%, 100%, 90% and 80% of native glenoid width after Latarjet was calculated by directly measuring the widest point of the glenoid and confirming accuracy based on the CT scan. Glenoid bone loss was established using a burr and the coracoid graft transfer was secured to the anteroinferior glenoid with two screws. The conjoined tendon was passed through a subscapularis split and the LTO was repaired with multiple Kirshner wires prior to each testing condition (Figure 2). Additionally, the rotator interval was closed and the capsule was repaired prior to each testing condition.The supraspinatus, subscapularis, infraspinatus and conjoined tendons were each loaded with 22N. Testing conditions included native glenohumeral joint, LTO, Bankart tear, and then 110%, 100%, 90% and 80% of glenoid width restoration with Latarjet. Glenohumeral translations and contact pressures were recorded with an anteroinferior load of 0 or 44N at 0 degrees of glenohumeral external rotation.Results:Progressive increases in anterior humeral head translation occurred with an anteroinferior load as the amount of glenoid width restored decreased (Figure 3). An anteroinferior load created an average of 5.5mm, 9.6mm, 3.3mm, 3.6mm, 9.2mm and 10.2mm of anterior translation in the LTO, Bankart, 110%, 100%, 90% and 80% of glenoid restoration cohorts, respectively. Greater glenoid bone loss also led to more contact pressure on the coracoid graft after Latarjet (Figure 4). An anteroinferior load produced 26.4%, 46.9%, 86.2% and 94.4% of the contact pressures on the coracoid graft relative to the native glenoid with glenoid width restored to 110%, 100%, 90% and 80%, respectively.Conclusions:There is an increase in anterior humeral head translation and contact pressure on the coracoid graft when 90% or less of the native glenoid width is restored with Latarjet. By determining the goals for glenoid width restoration after Latarjet, the findings of this study may provide guidance for patient-specific size requirements for the coracoid based on preoperative imaging. When greater than 90% of glenoid width cannot be restored with a Latarjet, surgeons may consider alternative graft sources.

Paper 51: Multiple Prior Dislocations Lead to Poorer Outcomes of Isolated Medial Patellofemoral Ligament Reconstruction: A Retrospective Chart Review

Objectives:Patellar dislocation is a common knee injury and up to 35% who dislocate can develop recurrent patellar instability. In the setting of recurrent instability, medial patellofemoral ligament reconstruction (MPFLR) often restores knee stability. There has been recent interest in the evaluation of patient and surgical factors that may influence the outcomes of isolated MPFLR. Much of the previous work has focused on influences of anatomical measures; however, patient and injury characteristics may also impact surgical outcomes. We hypothesize that patients who suffer > 2 patellar dislocations prior to MPFLR will demonstrate poorer patient-reported outcomes (PROs) than those who experience ≤ 2 prior dislocations.Methods:Records were reviewed to identify patients who underwent MPFLR at a single academic institution in the United States between 2008 and 2016. Patients were excluded if they underwent concomitant tibial tubercle osteotomy or fixation of an osteochondral fracture. Patient demographics (age, sex, BMI), number of prior patellar dislocations, and patient anatomical measures (Caton-Deschamps index, tibial tubercle-trochlear groove distance, and trochlear sulcus angle) were collected. PROs were assessed with Norwich Patellar Instability (NPI) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Marx activity score. Outcomes of those with > 2 or ≤ 2 patellar dislocations were compared using linear regression analysis.Results:A total of 160 patients were identified who underwent isolated MPFLR. Ninety-five patients (60%) were available to complete PROs at a mean follow-up of 4.8 years post-operation. Patients with < 2 dislocations were younger (≤ 2 dislocations: 20.7 ± 9.4yrs, > 2 dislocations: 27.4 ± 9.4yrs; p < 0.001), though there were no other differences between groups in terms of demographics or radiographic anatomical measures (Table 1). Controlling for age, sex, BMI, and anatomical factors linear regression analysis found that patients with > 2 dislocations had lower KOOS pain (p = 0.003), ADLs (p = 0.025), Sports/rec (p = 0.009), and knee related QOL (p = 0.008) subscales (Table 2).Conclusions:Patients who suffer > 2 patellar dislocations prior to MPFLR demonstrate poorer PROs at 4.8 years post-operation than those who suffer < 2 dislocations prior to surgery. To our knowledge, no other study has investigated the relationship between the number of pior patellar dislocations and outcomes following MPFLR. Our findings emphasize the role patient and injury factors may play in determining outcomes following MPFLR.Table 1.Comparison of patients based on number of prior dislocations controlling for age, sex, BMI, CDI, TT-TG distance, and sulcus angleTable 2.PROs for patients with ≤ 2 or > 2 patellar dislocations prior to MPFLR, controlling for age, sex, BMI, CDI, TT-TG distance, and sulcus angle

Trochlear Osteochondral Shell Allograft Technique to Treat Trochlear Dysplasia in the Setting of Chondral Damage and Chronic Patellar Instability

Chronic patellar instability is characterized by recurrent dislocation events due to anatomical distortions as well as insufficiency of surrounding stabilizing structures, ultimately impacting patients’ quality of life. In the setting of recurrent instability, patella alta, and trochlear dysplasia, there is also increased likelihood of symptomatic chondral damage in these patients. In this Technical Note, we describe the management of a patient with chronic lateral patellar instability, pain outside of dislocation events, and extensive surgical history to the knee. The surgical management included a combined approach, using a shell osteochondral allograft transplant to the trochlea, cylindrical osteochondral allograft transplantation to the patella, and revision tibial tubercle osteotomy with medial patellofemoral ligament reconstruction.

Management of Recurrent Anterior Shoulder Instability After Surgical Stabilization in Children and Adolescents.

Recurrent shoulder instability after stabilization is common in pediatric and adolescent athletes. The purpose of this review is to understand the risk factors that lead to failure of primary surgery and management principles in the setting of recurrent instability following surgical stabilization. Rates of recurrence after primary and revision surgical stabilization remain higher than desirable. Risk factors for failure in include glenoid and humeral bone loss, capsular or ligamentous laxity, and young age though few studies have focused specifically on the adolescent population. Arthroscopic, open, and bone block techniques have been described in this population similar to adults. Failure after a primary shoulder stabilization remains a common problem in adolescents in no small part because a high proportion of these athletes return to high levels of activity. A thorough understanding of the index procedure and patient-specific risk factors for failure are key to successful planning of revision surgery. The current literature does not allow for firm treatment recommendations in individual pediatric or adolescent athletes, but the guiding principles are similar to those in adults. Specifically, all bony and soft tissue pathology should be identified and assessed, with an understanding that simply repeating the steps of the index procedure typically results in poor outcomes, and often an "escalation" of surgical complexity is required at the time of revision. When appropriately indicated, arthroscopic or open soft tissue procedures and Latarjet coracoid transfer can be safely and successfully implemented for revision shoulder stabilization in young athletes.

Prospective Evaluation of Glenoid Bone Loss After First-time and Recurrent Anterior Glenohumeral Instability Events

Background: Determining the amount of glenoid bone loss in patients after anterior glenohumeral instability events is critical to guiding appropriate treatment. One of the challenges in treating the shoulder instability of young athletes is the absence of clear data showing the effect of each event. Purpose: To prospectively determine the amount of bone loss associated with a single instability event in the setting of first-time and recurrent instability. Study Design: Cohort study; Level of evidence, 2. Methods: The authors conducted a prospective cohort study of 714 athletes surveilled for 4 years. Baseline assessment included a subjective history of shoulder instability. Bilateral noncontrast shoulder magnetic resonance imaging (MRI) was obtained for all participants with and without a history of previous shoulder instability. The cohort was prospectively followed during the study period, and those who sustained an anterior glenohumeral instability event were identified. Postinjury MRI with contrast was obtained and compared with the screening MRI. Glenoid width was measured for each patient’s pre- and postinjury MRI. The projected total glenoid bone loss was calculated and compared for patients with a history of shoulder instability. Results: Of the 714 athletes (1428 shoulders) who were prospectively followed during the 4-year period, 22 athletes (23 shoulders) sustained a first-time anterior instability event (5 dislocations, 18 subluxations), and 6 athletes (6 shoulders) with a history of instability sustained a recurrent anterior instability event (1 dislocation, 5 subluxations). On average, there was statistically significant glenoid bone loss (1.84 ± 1.47 mm) after a single instability event (P < .001), equivalent to 6.8% (95% CI, 4.46%-9.04%; range, 0.71%-17.6%) of the glenoid width. After a first-time instability event, 12 shoulders (52%) demonstrated glenoid bone loss ≥5% and 4 shoulders, ≥13.5%; no shoulders had ≥20% glenoid bone loss. Preexisting glenoid bone loss among patients with a history of instability was 10.2% (95% CI, 1.96%-18.35%; range, 0.6%-21.0%). This bone loss increased to 22.8% (95% CI, 20.53%-25.15%; range, 21.2%-26.0%) after additional instability (P = .0117). All 6 shoulders with recurrent instability had ≥20% glenoid bone loss. Conclusion: Glenoid bone loss of 6.8% was observed after a first-time anterior instability event. In the setting of recurrent instability, the total calculated glenoid bone loss was 22.8%, with a high prevalence of bony Bankart lesions (5 of 6). The findings of this study support early stabilization of young active patients after a first-time anterior glenohumeral instability event.

Prospective Evaluation of Glenoid Bone Loss After First-Time and Recurrent Anterior Glenohumeral Instability Events

Objectives:Determining the amount of glenoid bone loss in patients following anterior glenohumeral instability events is critical to guiding appropriate treatment. One of the challenges in managing shoulder instability in young athletes is the absence of clear data showing the impact of each event. The purpose of this study was to prospectively determine the amount of bone loss associated with a single instability event, in the setting of both first-time and recurrent instability.Methods:We conducted a prospective cohort study of 714 athletes followed for four years. Baseline assessment included a subjective history of shoulder instability. Bilateral shoulder MRIs were obtained in all participants with and without a history of previous shoulder instability. The cohort was prospectively followed during the study period and those who sustained an anterior glenohumeral instability event were identified. A post-injury MRI was obtained and compared to the screening MRI. Glenoid width was measured for each patient’s pre- and post-injury MRI. The projected total glenoid bone loss was calculated and compared for patients with a prior history of shoulder instability.Results:Of the 714 athletes that were prospectively followed during the four-year period, 23 shoulders in 22 subjects sustained a first-time anterior instability event (5 dislocations, 18 subluxations), and six subjects with a previous history of instability sustained a recurrent anterior instability event (1 dislocation, 5 subluxations). On average, there was statistically significant glenoid bone loss (1.84 ± 1.47 mm) following a single instability event (p<0.001), equivalent to 6.8% (95% CI: 4.46%, 9.04%, range 0.71%-17.6%) of the glenoid width. Twelve shoulders (52%) demonstrated glenoid bone loss ≥ 5%, 4 shoulders demonstrated glenoid bone loss ≥13.5% and no shoulders had ≥20% glenoid bone loss after a first-time instability event. Pre-existing glenoid bone loss in subjects with a history of instability was 10.2% (95% CI: 1.96%, 18.35%, range 0.6% - 21.0%). This bone loss increased to 22.8% (95% CI: 20.53%, 25.15%, range 21.2% to 26.0%) following an additional instability event (P=0.0117). All six shoulders with recurrent instability had >20% glenoid bone loss.Conclusion:Glenoid bone loss of 6.8% was observed after a first-time anterior instability event. In the setting of recurrent instability, the total calculated glenoid bone loss was 22.8% with a high prevalence of bony Bankart lesions (5/6). The findings of this study support early stabilization of young, active subjects following a first-time anterior glenohumeral instability event.Figure 2.Clinical demonstration of a sagital en face MRI obtained prior to any instability event (A) and following a single subluxatiion event (B) with 14% bone loss and a bony Bankart.Table 2:Glenoid Bone Loss in First-time and Recurrent Instability CohortsInstability TypeNo. ShouldersΔ Glenoid Width (mm)ΔGlenoid Width (%)Total Glenoid Bone Loss* (%)P valueFirst-time231.85 ± 1.496.8%6.8%< .0001Recurrent63.75± 2.3713.6%22.8%.0117

Revision Total Hip Arthroplasty in the Setting of a Well-Fixed Cup: Early Report on the Cup-in-Cup Technique

AbstractWhen faced with a well-fixed acetabular component during revision total hip arthroplasty (THA) in the setting of recurrent instability, reconstructive options are limited, and consequences can prove dire if removal leads to severe bone loss or pelvic discontinuity. Our aims are to report the surgical technique, early survivorship, radiographic improvements, and complications on a consecutive, retrospective series of 13 hips in 12 patients who were treated with a cup-in-cup surgical technique to address multiply recurrent dislocations in the setting of a well-fixed cup. If determined to be stable and acceptably positioned upon intraoperative assessment, the acetabular component is retained, a second shell is cemented into the preexisting cup, and a dual mobility or standard polyethylene liner bearing is utilized. At 2-year minimum follow-up, the cup-in-cup arthroplasty exhibited an overall 85% survivorship. Two subjects required subsequent revisions: one for infection and one for ongoing instability in the setting of general noncompliance. No revisions were performed for loosening of the cup-in-cup interface. The median affected leg length was increased by 2.8 mm (p = 0.04) and horizontal offset improved by an average of 6.9 mm (p &lt; 0.001). There were a total of four dislocations in two subjects after cup-in-cup revision arthroplasty with no failures at the cup–cup cement interface. Our series demonstrates acceptable early outcomes in terms of improved stability and decreasing the need for further revision surgery while utilizing the cup-in-cup revision arthroplasty technique in situations of recurrent dislocations.

Glenoid Reconstruction With Distal Tibia Allograft for Recurrent Anterior Shoulder Instability.

Anterior glenoid bone loss is present in nearly all cases of recurrent anterior glenohumeral instability. Treating glenoid bone loss in the setting of recurrent instability is challenging, and often, soft tissue stabilization procedures in isolation are inadequate. The nonanatomic, incongruous joint resulting from most bony augmentation procedures has motivated investigators to find an alternative solution. Recently, the use of fresh distal tibia allograft has been reported as an anatomic, osteoarticular reconstructive option for restoring the glenoid arc and maintaining glenohumeral congruency. This article describes the surgical technique for glenoid reconstruction with distal tibia allograft for recurrent anterior shoulder instability. [Orthopedics. 2017; 40(1):e199-e205.].

Evaluation and management of patellar instability in pediatric and adolescent athletes.

Context:The rising popularity and intensity of youth sports has increased the incidence of patellar dislocation. These sports-related injuries may be associated with significant morbidity in the pediatric population. Treatment requires understanding and attention to the unique challenges in the skeletally immature patient.Evidence Acquisition:PubMed searches spanning 1970-2013.Study Design:Clinical review.Level of Evidence:Level 5.Results:Although nonoperative approaches are most often suitable for first-time patellar dislocations, surgical treatment is recommended for acute fixation of displaced osteochondral fractures sustained during primary instability and for patellar realignment in the setting of recurrent instability. While a variety of procedures can prevent recurrence, the risk of complications is not minimal.Conclusion:Patellar stabilization and realignment procedures in skeletally immature patients with recurrent patellar dislocation can effectively treat patellar instability without untoward effects on growth if careful surgical planning incorporates protection of growth parameters in the skeletally immature athlete.

The Importance of the Recognition and Treatment of Glenoid Bone Loss in an Athletic Population

Context:Osseous injury to the glenoid is increasingly being recognized as one of the most important aspects in the successful management of recurrent shoulder instability. Proper early recognition of glenoid bone injury in the setting of recurrent instability will lead to successful nonoperative and operative decision making, particularly in the athletic patient.Evidence Acquisition:We conducted a MEDLINE search on shoulder instability from 2000 to 2010. The emphasis was placed on patient-oriented Level 1 literature from 2000 to 2010.Results:After a traumatic anterior dislocation of the shoulder, the most common structural injury is an avulsion of the anteroinferior capsulolabrum, which is also known as a Bankart lesion. If this specific injury is accompanied by an associated fracture in the glenoid rim, the term bony Bankart lesion is more applicable. With diminished articular constraints, the glenohumeral joint is subject to recurrent instability, thereby potentiating the bony injury cycle. Additionally, patients with osseous defects usually complain of instability within the midranges of motion, or they recall a progression of instability. If glenoid bone loss is present, the humeral head often easily subluxates over the glenoid in the midranges of abduction (30°-90°) and lower levels of external rotation. Imaging workup should begin with plain radiographs, but advanced imaging should be obtained if there is any suspicion of bone loss. Treatment includes both nonoperative and operative interventions.Conclusions:Estimation of the amount of glenoid bone loss and the failure of nonoperative care is essential for guiding management, patient expectations, and surgical decision making.

Revision instability surgery after failed thermal capsulorraphy

Thermal capsulorraphy is the most recent innovation in the arthroscopic treatment of glenohumeral instability. This technique continues to gain in popularity despite the lack of well-defined criteria and indications for its clinical use. The technique involves the thermal treatment of capsular redundancy by the delivery of heat energy in the form of laser light or radio frequency. There are now many basic science studies reporting on the mechanism of thermal modification of capsular and ligamentous tissue 1–7 but there is less available literature reporting on clinical effects and patient outcome over time. Concerns have arisen regarding reports of complications occurring following thermal treatment of capsular tissue. 8,9 The complications include recurrent instability, restriction of motion, destruction of normal capsular tissue, and neurological complications. Patients with recurrent instability following thermal capsulorraphy may have one or more of these additional problems which would make any form of revision surgery a difficult undertaking. There are reports of patients with absent capsule, thin and friable capsular tissue and abnormal, thickened capsule. In the setting of recurrent instability, these complications have to be addressed differently, often necessitating the use of varied surgical techniques.