Matthew Bollier

The role of trochlear dysplasia in patellofemoral instability.

&NA; Trochlear dysplasia is characterized by abnormal trochlear morphology and a shallow groove. It is associated with recurrent patellar dislocation, but it is unclear whether the dysplasia is congenital, the result of lateral tracking and chronic instability, or caused by a combination of factors. Lateral radiographs elucidate the crossing sign and characteristic trochlear prominence. Recurrent patellofemoral instability is multifactorial, and each component must be considered in determining treatment. Managing other factors associated with recurrent instability may compensate for a deficient trochlea and provide stability. Medial patellofemoral ligament reconstruction is recommended for patellofemoral instability in the presence of trochlear dysplasia in patients without patella alta or increased tibial tubercle‐trochlear groove distance. Trochleoplasty should be reserved for severe dysplasia in which patellofemoral stability cannot otherwise be obtained.

Technical Failure of Medial Patellofemoral Ligament Reconstruction

In patients with chronic patellofemoral instability who have normal alignment and deficient proximal medial restraints, medial patellofemoral ligament (MPFL) reconstruction is a good option to treat patellar instability. However, medial subluxation, medial patellofemoral articular overload, and recurrent lateral instability are possible when the graft is positioned non-anatomically. The clinical presentation of MPFL femoral tunnel malpositioning has not been highlighted in the literature. We have had 5 patients referred to us after a malpositioned femoral MPFL graft led to disabling symptoms and a need for revision surgery. This report highlights the effects of a malpositioned graft and describes strategies to identify the anatomic MPFL insertion during surgery.

Management of glenoid and humeral bone loss.

Glenoid and humeral head bone deficiency is a common reason for recurrent anterior shoulder instability and failure of capsulolabral reconstruction. There is a strong association between the severity of the bone defects and the number and ease of recurrent instability. Clinical evaluation, advanced imaging, examination under anesthesia, and diagnostic arthroscopy are important in decision making. Glenoid bone loss greater than 20%, an engaging Hill-Sachs lesion, or Instability Severity Index Score greater than 6 are indications for an open bony procedure to restore the glenoid articular arc. Hill-Sachs lesions greater than 30% should be directly addressed with either an arthroscopic remplissage technique or open bone grafting procedure.

Biomechanical Evaluation of Margin Convergence

PURPOSE The aim of this study was to examine rotator cuff strain and gap size after margin convergence was performed for a large retracted rotator cuff tear. METHODS We tested 20 cadaveric shoulders using a custom shoulder testing system. A large retracted rotator cuff tear was created by removing the supraspinatus muscle-tendon unit to provide a reproducible model. Margin convergence was performed and strain was measured by use of differential variable reluctance transducers in the intact state, after a massive rotator cuff tear was created, and after each of 5 margin convergence sutures were placed. Data were obtained at 0° and 60° of abduction and with internal and external rotational torques applied to the humerus. Gap size was measured before and after margin convergence sutures were placed. RESULTS Strain was significantly reduced at all degrees of rotation in 0° of abduction after margin convergence sutures were placed (P < .05). There was a significantly significant decrease in gap size with each suture: 50% with the first suture, 60% with the second suture, 67% with the third suture, and 75% with the fourth suture (P < .05). There was only minimal intrinsic rotator cuff tension during knot tying, with each subsequent suture having less of an effect than the previous. Four margin convergence sutures resulted in a mean of 5 mm of anterior humeral head translation. CONCLUSIONS There was a significant decrease in rotator cuff strain and gap size after margin convergence was performed for a large retracted tear. The first margin convergence suture caused the greatest increase in intrinsic rotator cuff tension, with each subsequent suture having a similar but less dramatic effect. CLINICAL RELEVANCE Biomechanical rationale exists for the use of margin convergence in large retracted rotator cuff tears.

Management of the failed AC joint reconstruction: causation and treatment.

With recent studies showing improved biomechanical behavior of anatomic acromioclavicular joint reconstructions, these techniques are more frequently being performed. With both the more historic methods of fixation such as coracoacromial ligament transfer along with the newer anatomic reconstruction, potential for failure exists. However, there is a paucity of literature addressing these failures and possible treatment options. The purpose of this review is to report cases of failed reconstructions, describe failure mechanisms, and propose treatment options.

Performance of PROMIS Instruments in Patients With Shoulder Instability

Background: Shoulder instability is a relatively common condition occurring in 2% of the population. PROMIS (Patient-Reported Outcome Measurement Information System) was developed by the National Institutes of Health in an effort to advance patient-reported outcome (PRO) instruments by developing question banks for major health domains. Purpose: To compare PROMIS instruments to current PRO instruments in patients who would be undergoing operative intervention for recurrent shoulder instability. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 74 patients with a primary diagnosis of shoulder instability who would be undergoing surgery were asked to fill out the American Shoulder and Elbow Surgeons shoulder assessment form (ASES), Marx shoulder activity scale (Marx), Short Form–36 Health Survey Physical Function subscale (SF-36 PF), Western Ontario Shoulder Instability Index (WOSI), PROMIS physical function computer adaptive test (PF CAT), and PROMIS upper extremity item bank (UE). Correlation between PRO instruments was defined as excellent (>0.7), excellent-good (0.61-0.7), good (0.4-0.6), and poor (0.2-0.3). Results: Utilization of the PROMIS UE demonstrated excellent correlation with the SF-36 PF (r = 0.78, P < .01) and ASES (r = 0.71, P < .01); there was excellent-good correlation with the EQ-5D (r = 0.66, P < .01), WOSI (r = 0.63, P < .01), and PROMIS PF CAT (r = 0.63, P < .01). Utilization of the PROMIS PF CAT demonstrated excellent correlation with the SF-36 PF (r = 0.72, P < .01); there was excellent-good correlation with the ASES (r = 0.67, P < .01) and PROMIS UE (r = 0.63, P < .01). When utilizing the PROMIS UE, ceiling effects were present in 28.6% of patients aged 18 to 21 years. Patients, on average, answered 4.6 ± 1.8 questions utilizing the PROMIS PF CAT. Conclusion: The PROMIS UE and PROMIS PF CAT demonstrated good to excellent correlation with common shoulder and upper extremity PRO instruments as well as the SF-36 PF in patients with shoulder instability. In patients aged ≤21 years, there were significant ceiling effects utilizing the PROMIS UE. While the PROMIS PF CAT appears appropriate for use in adults of any age, our findings demonstrate that the PROMIS UE has significant ceiling effects in patients with shoulder instability who are ≤21 years old, and we do not recommend use of the PROMIS UE in this population.

Anterior cruciate ligament and medial collateral ligament injuries.

The diagnosis and treatment of combined anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries have evolved over the past 30 years. A detailed physical examination along with careful review of the magnetic resonance imaging and stress radiographs will guide decision making. Early ACL reconstruction and acute MCL repair are recommended when there is increased medial joint space opening with valgus stress in extension, a significant meniscotibial deep MCL injury (high-riding medial meniscus), or a displaced tibial-sided superficial MCL avulsion (stener lesion of the knee). Delayed ACL reconstruction to allow for MCL healing is advised when increased valgus laxity is present only at 30 degrees of flexion and not at 0 degree. However, at the time of ACL surgery, medial stability has to be re-assessed after the reconstruction is completed. In patients with neutral alignment in the chronic setting, graft reconstruction of both the ACL and MCL is recommended.

Repair of Distal Biceps Tendon Ruptures Using the EndoButton

Biomechanical and clinical studies have demonstrated the importance of the biceps muscle in upper extremity function, and most surgeons would recommend anatomic repair of the ruptured distal biceps tendon to the radial tuberosity to prevent the loss of strength in forearm supination and elbow flexion.1-4 In rupture, the tendon usually avulses from the radial tuberosity. Two main approaches have been described for reattachment: the single-incision anterior approach and the two-incision technique.5,6 The two-incision technique typically involves bone tunnels to secure the tendon to the radial tuberosity. However, this technique can be associated with radioulnar synostosis.1,5,7 A single-incision anterior approach with the use of suture anchors or interference screw fixation has become popular in recent years.8-12 However, with this technique, there are technical challenges associated with knot-tying and tendon tensioning in the muscular forearm. Although initially developed for fixation of an anterior cruciate ligament graft, EndoButton (Acufex Microsurgical, Mansfield, MA) repair of distal biceps tendon ruptures provides strong fixation to allow early motion, lessens technical difficulty in securing fixation, and utilizes a bone socket to maximize tendon healing. EndoButton repair of distal biceps tendon ruptures was first described by Bain et al13 in 2000 for use in a single-incision anterior approach. These authors reported satisfactory outcomes with early active mobilization in all 12 patients, with no complications. All patients regained grade 5 strength and returned to full activities. Greenberg et al14 reported their results using the EndoButton in both biomechanical and clinical studies. They showed that the EndoButton was three times stronger than a bony bridge and two times stronger than a DePuy Mitek anchor (Warsaw, IN). In addition, at a mean of 20 months postoperatively, patients had regained 97% of flexion strength and 82% of supination strength.14 Mazzocca et al15 compared four techniques of distal biceps tendon repair; the EndoButton technique had the highest load to failure. Other studies using the EndoButton have demonstrated excellent biomechanical strength, high patient satisfaction, ability to allow early motion, a very low incidence of complications, and an increased ability to repair chronic retracted tears.13,14,16,17

Distal realignment: indications, technique, and results.

When appropriately indicated, distal realignment procedures can produce consistent clinical results. Indications for distal realignment include lateral patellofemoral instability, anterior knee pain with associated lateral or distal patellofemoral cartilage lesion, and cases with significant lateral patellofemoral overload or tilt. In cases of patellofemoral instability, it is important to determine whether proximal stabilization, distal realignment, or both is needed. If distal realignment is indicated, several anatomic variables must be considered to determine the location and obliquity of the osteotomy when using multiplanar osteotomy techniques.

Effect of body mass index on patients with multiligamentous knee injuries.

PURPOSE Our goal was to evaluate the impact of body mass index (BMI) on complications and associated injuries in patients undergoing surgical treatment for multiligamentous knee injuries (MLKIs). METHODS Over a period of 10 years, 126 MLKIs (123 patients) were included in the study. The inclusion criteria were (1) injury to 2 or more knee ligaments, (2) multiligament repair and/or reconstruction performed by 1 of 3 sports medicine orthopaedic surgeons at our institution, and (3) minimum of 1 year of follow-up. A chart review was performed to collect demographic data, mechanism of injury, ligaments involved, complications, and associated neurovascular injuries. Lastly, patients were divided by BMI into non-obese (<30 kg/m(2)) and obese (≥30 kg/m(2)) groups. RESULTS Of the 126 MLKIs, 87 occurred in non-obese patients and 39 occurred in obese patients. Surgical complication rates for non-obese and obese patients were 8.05% and 15.4%, respectively (P = .21). Revisions were needed in 8.05% and 5.1% of patients in these groups, respectively (P = .72). Three wound complications were found in the obese group only. Vascular injuries were found in 2.3% and 7.7% of patients in the non-obese and obese groups, respectively (P = .17). The rates of nerve injuries were 11.49% and 20.51%, respectively (P = .18). Patients in the obese group were most likely to have an MLKI from low-energy mechanisms, disregarding sports-related injuries (51.28%, P = .02). Using a logistic model and BMI as a continuous variable, we found that a 1-unit increase in BMI increased the odds ratio of complications by 9.2%, with statistical significance (P = .0174). In addition, post hoc power analysis using previous literature showed that this study could produce satisfactory power. CONCLUSIONS Our results indicate that (1) obese individuals are significantly more likely to have an MLKI caused by low-energy mechanisms and (2) complication rates increase by 9.2% for every 1-unit increase in BMI. LEVEL OF EVIDENCE Level III, retrospective comparative study.