Matthew Bollier | The University of Iowa (original) (raw)

Papers by Matthew Bollier

Current Orthopaedic Practice, 2010

Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Cu... more Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Current Orthopaedic Practice. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information ...

The Journal of the American Academy of Orthopaedic Surgeons, 2011

Trochlear dysplasia is characterized by abnormal trochlear morphology and a shallow groove. It is... more 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.

The Iowa orthopaedic journal, 2012

Trochlear dysplasia is a risk factor for patellofemoral instability. Trochleoplasty involves resh... more Trochlear dysplasia is a risk factor for patellofemoral instability. Trochleoplasty involves reshaping the trochlear groove to provide increased patellofemoral stability. We obtained post-operative radiographs, MRI, and outcome scores in 6 patients who underwent this procedure. All 6 of the patients were satisfied with their outcome following trochleoplasty with no recurrent instability events. Mean bony sulcus angles decreased from 148 degrees to 129 degrees. However, 4 of the 6 patients reported anterior knee pain. Similar to previously published studies, trochleoplasty can reliably improve patellofemoral stability in patients with severe trochlear dysplasia, but a high percentage of patients will have pain postoperatively.

The Iowa orthopaedic journal, 2013

Medial Patellofemoral Ligament (MPFL) reconstruction is an accepted treatment for recurrent patel... more Medial Patellofemoral Ligament (MPFL) reconstruction is an accepted treatment for recurrent patellofemoral instability when patients have normal alignment and deficient proximal medial restraints. There are several reports of malpositioned femoral tunnels leading to poor outcomes. The purpose of this study was to analyze femoral tunnel placement after MPFL reconstruction and correlate this with outcomes. We performed a retrospective review of MPFL reconstructions done at our institution from 2006-2010. We then evaluated lateral radiographs and measured the distance between the radiographic femoral MPFL isometric point and the center of the femoral tunnel. We also evaluated post-operative KOOS scores. The average distance from the femoral tunnel to the MPFL isometric point was 13.25 mm. Sixty-four percent of tunnels were placed greater than nine millimeters from our isometric point and deemed to be malpositioned. There was no statistically significant difference in outcomes scores in...

Sports medicine and arthroscopy review, 2010

With recent studies showing improved biomechanical behavior of anatomic acromioclavicular joint r... more 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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2014

Our goal was to evaluate the impact of body mass index (BMI) on complications and associated inju... more 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). 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. 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. 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 III, retrospective comparative study.

Sports Medicine and Arthroscopy Review, 2010

With recent studies showing improved biomechanical behavior of anatomic acromioclavicular joint r... more 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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2011

In patients with chronic patellofemoral instability who have normal alignment and deficient proxi... more 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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2011

Purpose: The aim of this study was to examine rotator cuff strain and gap size after margin conve... more 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 Ͻ .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 Ͻ .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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2010

Purpose: The aim of this study was to assess the contact pressure, force, and area over time for ... more Purpose: The aim of this study was to assess the contact pressure, force, and area over time for 4 common arthroscopic rotator cuff repair techniques. Methods: The transosseous-equivalent, singlerow, triangle double-row, and suture-chain transosseous repair techniques were used to repair a full-thickness tear of the supraspinatus in 16 cadaveric shoulders. Continuous data points were collected immediately after repair and for 160 minutes at set time intervals by use of a custom thin film pressure sensor. Results: Each of the 4 rotator cuff repair techniques showed decreased contact force, pressure, and area 160 minutes after the repair was performed. The transosseous-equivalent construct had the highest contact pressure and force initially and at all time points up to 160 minutes. Although the 3 double-row constructs had greater pressure and force at all time points compared with the single-row repair, only the transosseous-equivalent group showed a statistically greater pressure and force when compared with single-row repair (P Ͻ .05). Conclusions: Contact pressure, force, and pressurized footprint area decrease 160 minutes after repair regardless of repair technique. The transosseous-equivalent group had the highest contact pressure and force at all time points. Clinical Relevance: The decrease in contact pressure and force after rotator cuff repair may have important implications in evaluating tendon-to-bone healing and determining the optimal rehabilitation protocol.

The Journal of Bone and Joint Surgery (American), 2012

The role of medial patellofemoral ligament reconstruction in reestablishing patellofemoral joint ... more The role of medial patellofemoral ligament reconstruction in reestablishing patellofemoral joint stability has recently been reported with increasing frequency. The purpose of this study was to review the reported complications of medial patellofemoral ligament reconstruction, highlight the common technical errors, and discuss the potential complications that can arise from this procedure. We review the literature on medial patellofemoral ligament reconstruction, including the reported causes of failure. In addition, we present three cases and discuss the multiple factors that are crucial for success, including patient selection, tunnel placement, graft isometry, and determination of the need for concurrent realignment surgery. The principles of surgical management require a thorough understanding of proper patient selection and of the interaction between the roles of the osseous and soft-tissue restraints on the patella. Creating a logical treatment algorithm based on pathoanatomy can elucidate the need for concurrent distal realignment procedures. Tunnel positioning is critical in recreating appropriate patellofemoral alignment. The reported complications include patellofemoral arthrosis, graft impingement, and graft failure. Many of the complications that can arise from medial patellofemoral ligament reconstruction are the result of technical error and can be avoided by understanding the potential complications associated with this procedure.

Current Orthopaedic Practice, 2010

Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Cu... more Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Current Orthopaedic Practice. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information ...

The Journal of the American Academy of Orthopaedic Surgeons, 2011

Trochlear dysplasia is characterized by abnormal trochlear morphology and a shallow groove. It is... more 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.

The Iowa orthopaedic journal, 2012

Trochlear dysplasia is a risk factor for patellofemoral instability. Trochleoplasty involves resh... more Trochlear dysplasia is a risk factor for patellofemoral instability. Trochleoplasty involves reshaping the trochlear groove to provide increased patellofemoral stability. We obtained post-operative radiographs, MRI, and outcome scores in 6 patients who underwent this procedure. All 6 of the patients were satisfied with their outcome following trochleoplasty with no recurrent instability events. Mean bony sulcus angles decreased from 148 degrees to 129 degrees. However, 4 of the 6 patients reported anterior knee pain. Similar to previously published studies, trochleoplasty can reliably improve patellofemoral stability in patients with severe trochlear dysplasia, but a high percentage of patients will have pain postoperatively.

The Iowa orthopaedic journal, 2013

Medial Patellofemoral Ligament (MPFL) reconstruction is an accepted treatment for recurrent patel... more Medial Patellofemoral Ligament (MPFL) reconstruction is an accepted treatment for recurrent patellofemoral instability when patients have normal alignment and deficient proximal medial restraints. There are several reports of malpositioned femoral tunnels leading to poor outcomes. The purpose of this study was to analyze femoral tunnel placement after MPFL reconstruction and correlate this with outcomes. We performed a retrospective review of MPFL reconstructions done at our institution from 2006-2010. We then evaluated lateral radiographs and measured the distance between the radiographic femoral MPFL isometric point and the center of the femoral tunnel. We also evaluated post-operative KOOS scores. The average distance from the femoral tunnel to the MPFL isometric point was 13.25 mm. Sixty-four percent of tunnels were placed greater than nine millimeters from our isometric point and deemed to be malpositioned. There was no statistically significant difference in outcomes scores in...

Sports medicine and arthroscopy review, 2010

With recent studies showing improved biomechanical behavior of anatomic acromioclavicular joint r... more 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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2014

Our goal was to evaluate the impact of body mass index (BMI) on complications and associated inju... more 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). 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. 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. 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 III, retrospective comparative study.

Sports Medicine and Arthroscopy Review, 2010

With recent studies showing improved biomechanical behavior of anatomic acromioclavicular joint r... more 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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2011

In patients with chronic patellofemoral instability who have normal alignment and deficient proxi... more 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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2011

Purpose: The aim of this study was to examine rotator cuff strain and gap size after margin conve... more 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 Ͻ .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 Ͻ .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.

Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2010

Purpose: The aim of this study was to assess the contact pressure, force, and area over time for ... more Purpose: The aim of this study was to assess the contact pressure, force, and area over time for 4 common arthroscopic rotator cuff repair techniques. Methods: The transosseous-equivalent, singlerow, triangle double-row, and suture-chain transosseous repair techniques were used to repair a full-thickness tear of the supraspinatus in 16 cadaveric shoulders. Continuous data points were collected immediately after repair and for 160 minutes at set time intervals by use of a custom thin film pressure sensor. Results: Each of the 4 rotator cuff repair techniques showed decreased contact force, pressure, and area 160 minutes after the repair was performed. The transosseous-equivalent construct had the highest contact pressure and force initially and at all time points up to 160 minutes. Although the 3 double-row constructs had greater pressure and force at all time points compared with the single-row repair, only the transosseous-equivalent group showed a statistically greater pressure and force when compared with single-row repair (P Ͻ .05). Conclusions: Contact pressure, force, and pressurized footprint area decrease 160 minutes after repair regardless of repair technique. The transosseous-equivalent group had the highest contact pressure and force at all time points. Clinical Relevance: The decrease in contact pressure and force after rotator cuff repair may have important implications in evaluating tendon-to-bone healing and determining the optimal rehabilitation protocol.

The Journal of Bone and Joint Surgery (American), 2012

The role of medial patellofemoral ligament reconstruction in reestablishing patellofemoral joint ... more The role of medial patellofemoral ligament reconstruction in reestablishing patellofemoral joint stability has recently been reported with increasing frequency. The purpose of this study was to review the reported complications of medial patellofemoral ligament reconstruction, highlight the common technical errors, and discuss the potential complications that can arise from this procedure. We review the literature on medial patellofemoral ligament reconstruction, including the reported causes of failure. In addition, we present three cases and discuss the multiple factors that are crucial for success, including patient selection, tunnel placement, graft isometry, and determination of the need for concurrent realignment surgery. The principles of surgical management require a thorough understanding of proper patient selection and of the interaction between the roles of the osseous and soft-tissue restraints on the patella. Creating a logical treatment algorithm based on pathoanatomy can elucidate the need for concurrent distal realignment procedures. Tunnel positioning is critical in recreating appropriate patellofemoral alignment. The reported complications include patellofemoral arthrosis, graft impingement, and graft failure. Many of the complications that can arise from medial patellofemoral ligament reconstruction are the result of technical error and can be avoided by understanding the potential complications associated with this procedure.