Cost-utility analysis of robotic arm-assisted medial compartment knee arthroplasty

Aims

To perform an incremental cost-utility analysis and assess the impact of differential costs and case volume on the cost-effectiveness of robotic arm-assisted unicompartmental knee arthroplasty (rUKA) compared to manual (mUKA).

Methods

This was a five-year follow-up study of patients who were randomized to rUKA (n = 64) or mUKA (n = 65). Patients completed the EuroQol five-dimension questionnaire (EQ-5D) preoperatively, and at three months and one, two, and five years postoperatively, which was used to calculate quality-adjusted life years (QALYs) gained. Costs for the primary and additional surgery and healthcare costs were calculated.

Results

rUKA was associated with a relative 0.012 QALY gain at five years, which was associated with an incremental cost per QALY of £13,078 for a unit undertaking 400 cases per year. A cost per QALY of less than £20,000 was achieved when ≥ 300 cases were performed per year. However, on removal of the cost for a revision for presumed infection (mUKA group, n = 1) the cost per QALY was greater than £38,000, which was in part due to the increased intraoperative consumable costs associated with rUKA (£626 per patient). When the absolute cost difference (operative and revision costs) was less than £240, a cost per QALY of less than £20,000 was achieved. On removing the cost of the revision for infection, rUKA was cost-neutral when more than 900 cases per year were undertaken and when the consumable costs were zero.

Conclusion

rUKA was a cost-effective intervention with an incremental cost per QALY of £13,078 at five years, however when removing the revision for presumed infection, which was arguably a random event, this was no longer the case. The absolute cost difference had to be less than £240 to be cost-effective, which could be achieved by reducing the perioperative costs of rUKA or if there were increased revision costs associated with mUKA with longer follow-up.

The Anterior Fibers of the Superficial MCL and the ACL Restrain Anteromedial Rotatory Instability

BACKGROUND

There is limited knowledge about how the anterior cruciate ligament (ACL) and capsuloligamentous structures on the medial side of the knee act to control anteromedial rotatory knee instability.

PURPOSE

To investigate the contribution of the medial retinaculum, capsular structures (anteromedial capsule, deep medial collateral ligament [MCL], and posterior oblique ligament), and different fiber regions of the superficial MCL to restraining knee laxity, including anteromedial rotatory instability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic testing system in a position-controlled mode. Loads of 10 N·m valgus rotation, 5 N·m tibial external rotation, 5 N·m tibial internal rotation, and 134 N anterior tibial translation in 5 N·m external rotation were applied at different flexion angles. The motion of the intact knee at 0° to 120° of flexion was replicated after sequential excision of the sartorial fascia; anteromedial retinaculum; anteromedial capsule; anterior, middle, and posterior fibers of the superficial MCL; the deep MCL; the posterior oblique ligament; and the ACL. The reduction in force/torque indicated the contribution of each resected structure to resisting laxity. A repeated-measures analysis of variance with a post hoc Bonferroni test was used to analyze the relative force and torque changes from the intact state.

RESULTS

The superficial MCL was the most important restraint to valgus rotation from 0° to 120° and provided the largest contribution to resisting external rotation between 30° and 120° of knee flexion, gradually increasing from 25.2% ± 7.4% at 30° to 36.9% ± 15.4% at 90°. The posterior oblique ligament contributed significantly to resisting valgus rotation only in extension (17.2% ± 12.1%) but was the major restraint to internal rotation at 0° (46.7% ± 13.1%) and 30° (30.4% ± 17.7%) of flexion. The sartorial fascia and anteromedial retinaculum resisted ER at all knee flexion angles (P < .05) and was the single most important restraint in the extended knee (19.5% ± 11%). The capsular structures (anteromedial capsule and deep MCL) had a combined contribution of 20% ± 11.5% at 0° and 23.4% ± 10.5% at 120° of knee flexion but were less important from 30° to 90°. The ACL was the primary restraint to anterior tibial translation in external rotation between 0° and 60° of flexion (50.2% ± 16.9% at 30°), but the superficial MCL was more important at 90° to 120° of knee flexion (36.8% ± 16.4% at 90°). The anterior, middle, and posterior regions of the superficial MCL contributed differently to the simulated laxity tests. The anterior fibers were the most important part of the superficial MCL in resisting external rotation and combined anterior tibial translation in external rotation.

CONCLUSION

The superficial MCL not only was the primary restraint to valgus rotation throughout the range of knee flexion but also importantly contributed to resisting anterior tibial translation in external rotation, particularly in deeper flexion in the cadaveric model. The anterior fibers of the superficial MCL are the most important superficial MCL fibers in resisting anterior tibial translation in external rotation. This study suggests that a medial reconstruction that reproduces the function of the posterior MCL fibers and posterior oblique ligament may not best control anteromedial rotatory instability.

CLINICAL RELEVANCE

Based on these data, there is a need for an individualized medial reconstruction to address different types of medial injury patterns and instabilities.

15-Year Follow-Up of Mobile Bearing Medial Unicompartmental Knee Arthroplasty

INTRODUCTION

Medial unicompartmental knee arthroplasty (UKA) is a successful treatment for antero-medial osteoarthritis. However, there are few published studies on the long-term survival of this procedure. The purpose of this study was to review the 15-year minimum outcomes and survival of a mobile-bearing medial UKA.

METHODS

A retrospective review was performed between July 2004 and December 2006 of all patients who underwent a medial UKA eligible for a minimum of 15-year follow-up. The initial query revealed 299 patients (349 knees). One hundred-seventeen patients died or were lost to follow-up, leaving 182 patients (219 knees) for analyses. Clinical outcomes and survivorship were analyzed.

RESULTS

There were 59 implant-related reoperations which occurred at a mean of 10 years (range, 0 to 16 years). The most common reasons for reoperation were arthritic progression (9.1%) and aseptic loosening (9.1%). The 10-year survival with revision to TKA was 89% (95% confidence interval: 86% to 92.4%), and the 15-year survival was 84.1% (95% confidence interval: 80.3% to 88%). There were no statistically significant differences in survival between sex, body mass index, and age. Patients who were not revised had statistically significant improvements in knee range of motion and Knee Society scores.

CONCLUSIONS

This study found similar long-term survival of a medial mobile-bearing UKA to published total knee arthroplasty outcomes. The implant evaluated in this study has undergone subsequent improvements in instrumentation and design. Further analyses should be performed on the long-term outcomes of the current implant platform.

Impact of Proximal Tibial Varus Anatomy on Survivorship After Medial Unicondylar Knee Arthroplasty

BACKGROUND

Precise indications for medial unicondylar knee arthroplasty (UKA) continue to be defined. It is unclear if patients who have proximal tibia vara should be considered candidates for UKA. The purpose of this study was to evaluate the impact of proximal tibial varus alignment on outcomes after UKA.

METHODS

A retrospective review identified 2,416 patients (3,029 knees) who underwent mobile-bearing medial UKA with 2-year minimum follow-up or revision. Preoperative radiographs were evaluated, and medial proximal tibial angle (mPTA) was measured. Patients were grouped into two groups as follows: mPTA <80 degrees and mPTA ≥80 degrees. Analyses were performed on the impact of mPTA on clinical outcomes, all-cause revisions, and tibial failures.

RESULTS

At a mean follow-up of 5 years (range, 0.5 years to 12.8 years), there was not a statistically significant difference in clinical outcomes nor increased risk for all-cause revision or tibial failure in patients who had an mPTA <80°. Mean mPTA in patients who had tibial failures was 82.5° and not significantly different than those who did not have a tibial failure (82.9°) (P = .289). Tibial failure rate in knees with an mPTA <80° was 2.2% and not significantly different than knees with an mPTA ≥80° at 1.4% (P = .211). The all-cause revision rate in knees with an mPTA <80° was 5.8% and was not significantly different than knees with an mPTA ≥80° at 4.9% (P = .492).

CONCLUSION

Patients who have tibia vara are not at increased risk for tibial related or all-cause failure in medial UKA. This data may allow surgeons to increase their indications for medial UKA.

Microscopic Over-under Versus Medial Tympanoplasty for Larger Tympanic Membrane Perforations

OBJECTIVES

To identify the differences in hearing, anatomical success rate, functional success rate, and complications between over-under tympanoplasty and medial tympanoplasty procedures.

METHODS

The clinical data of patients with tympanic membrane perforation repaired by medial tympanoplasty between January 2011 and December 2016 and by over-under tympanoplasty between January 2017 and December 2020 were retrospectively analyzed. We evaluated the differences between medial tympanoplasty and over-under tympanoplasty.

RESULTS

The overall success rate of over-under tympanoplasty was higher than that of medial tympanoplasty (90.76% vs 81.31%). In large perforations, the success rate of over-under tympanoplasty was higher than that of medial tympanoplasty (89.80% vs 71.43%). There was no statistically significant difference in the success rate between the two treatment groups for moderate perforations. Furthermore, there was no statistically significant difference in the incidence of complications between the two groups (P = .2637).

CONCLUSIONS

Over-under tympanoplasty is more suitable for large perforations of the tympanic membrane and has a higher success rate as compared to medial tympanoplasty.

COMPARISON OF RETROBULBAR, SUB-TENON ANESTHESIA AND MEDIAL CANTHUS EPISCLERAL ANESTHESIA FOR 25-GAUGE POSTERIOR VITRECTOMY

PURPOSE

The aim of the study is to compare the efficacy, safety, and globe akinesia between retrobulbar anesthesia, sub-Tenon anesthesia, and medial canthus episcleral anesthesia for 25-gauge posterior vitrectomy.

METHODS

A total of 340 25-gauge vitrectomy data sheets were retrospectively collected between November 2017 and June 2019. Ninety patients were included in the study. These patients were matched by sex and age to receive retrobulbar anesthesia (group 1, n = 30), sub-Tenon anesthesia (group 2, n = 30), and medial canthus episcleral anesthesia (group 3, n = 30). Globe akinesia was recorded after the injection of anesthetic at 2, 5, and 10 minute time intervals. Patients were asked to rate the pain during administration of anesthesia, during surgery, and postoperatively using the visual analog pain scale.

RESULTS

For a perfect block, at 10 minutes, retrobulbar outperformed both sub-Tenon and medial canthus episcleral anesthesia which seemed quite similar. During administration, the three techniques did not show statistically different effects on pain. Regarding perioperative pain, retrobulbar outperformed medial canthus episcleral anesthesia.

CONCLUSION

All three techniques allowed for safe surgery. Retrobulbar obtained the best results, although sub-Tenon proved to be a valid alternative. Medial canthus episcleral anesthesia obtained mostly good and fair blocks and acceptable pain levels during surgery. Further studies should investigate whether optimal anesthetic efficacy can be obtained with sub-Tenon and medial canthus episcleral techniques when higher volumes are used.

Early and mid-term outcomes of open popliteal artery aneurysm repair with prosthetic grafts

OBJECTIVES

The aim of this study is to assess the early and mid-term outcomes of open surgical repair (OR) for popliteal artery aneurysm (PAA) with prosthetic grafts.

MATERIALS AND METHODS

The pre-, intra-, and postoperative data of all patients who underwent PAA OR with prosthetic grafts at our Institution between January 2009 and July 2019 were included in a prospectively maintained database which was retrospectively analysed. Primary patency was defined as uninterrupted flow (<50% stenosis) in the graft with no additional procedures performed. Secondary patency was defined as the restoration of graft patency.

RESULTS

Eighty-two patients underwent OR for 104 PAA (age: 71, 67-78; 82 males) with prosthetic grafts. Seventy-two aneurysms (68%) were asymptomatic. The median diameter was 30mm (24-37). A medial approach was used in 35 aneurysms (34%) while a posterior approach (PA) in 69 (65%). Repairs either consisted of aneurysmectomy or aneurysm ligation without removal with an interposition graft with end-to-end anastomoses. Median operative time was 120 (103-142) minutes. The estimated blood loss (EBL) was 281 (150-281) ml. Only one patient treated by PA sustained a permanent peroneal nerve lesion, and a second patient treated via the same approach needed a surgical revision due to bleeding on postoperative day two. No temporary lesions were recorded. There were no early amputations. No perioperative deaths occurred. The median length of stay (LOS) was 3 (3-4) days. An expanded poly-tetra-flour-ethylene graft was used in 102 cases (98%) and a Dacron graft in the remain two cases (2%). As for the caliber, the 8mm graft was used in 64 cases (62%). Median follow-up was 34.6 (8.5-62.7) months. There was no related mortality. Nineteen PAA underwent reintervention with primary and secondary rate patency of 78% and 88% at three years. The median time to reintervention was 28.3 months.

CONCLUSIONS

Popliteal artery aneurysms open repair with prosthetic grafts are safe and feasible, with good mid-term results and satisfactory primary and secondary patency at three years.

Fixed-Bearing Medial Unicompartmental Knee Arthroplasty in Patients Younger Than 55 Years of Age at 4-19 Years of Follow-Up: A Concise Follow-Up of a Previous Report

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) in isolated unicompartmental disease; however, mid-term to long-term results in young patients are unknown. The purpose of this study is to determine the mid-term outcomes of fixed-bearing medial UKA in patients less than 55 years of age.

METHODS

Seventy-seven fixed-bearing medial UKAs in patients less than 55 years of age (mean 49.9, range 38-55) from a previously published report were retrospectively reviewed at a mean follow-up of 11.2 years (range 4.1-19.2).

RESULTS

Eleven knees were converted to TKA (14.3%) at 0.7-13.8 years postoperatively. The indications for revision included 7 for unexplained pain (9.1%), 2 for grade 4 arthritic progression (1 isolated lateral and 1 lateral and patellofemoral compartments; 2.6%), 1 for polyethylene wear (1.3%), and 1 for femoral component loosening (1.3%). Predicted survivorship free from component revision was 90.4% (95% confidence interval 86.9-93.9) at 10 years and 75.1% (95% confidence interval 66.2-84.0) at 19 years. The mean Knee Society Score improved from a mean of 51.9-88.6 points (P < .001). Of the 52 knees with 4-year minimum radiographs, 3 (5.8%) developed isolated grade 4 patellofemoral arthritis that was asymptomatic, and no knees had evidence of component loosening or osteolysis.

CONCLUSION

Fixed-bearing medial UKA is a durable option for young patients with unicompartmental arthritis, with good clinical outcomes at mid-term follow-up. Unexplained pain was the most common reason for revision to TKA.

Expression and Distribution of Neuropeptide-Expressing Cells Throughout the Rodent Paraventricular Nucleus of the Thalamus

The paraventricular nucleus of the thalamus (PVT) has been shown to make significant contributions to affective and motivated behavior, but a comprehensive description of the neurochemicals expressed in the cells of this brain region has never been presented. While the PVT is believed to be composed of projection neurons that primarily use as their neurotransmitter the excitatory amino acid, glutamate, several neuropeptides have also been described in this brain region. In this review article, we combine published literature with our observations from the Allen Brain Atlas to describe in detail the expression and distribution of neuropeptides in cells throughout the mouse and rat PVT, with a special focus on neuropeptides known to be involved in behavior. Several themes emerge from this investigation. First, while the majority of neuropeptides are expressed across the antero-posterior axis of the PVT, they generally exist in a gradient, in which expression is most dense but not exclusive in either the anterior or posterior PVT, although other neuropeptides display somewhat more equal expression in the anterior and posterior PVT but have reduced expression in the middle PVT. Second, we find overall that neuropeptides involved in arousal are more highly expressed in the anterior PVT, those involved in depression-like behavior are more highly expressed in the posterior PVT, and those involved in reward are more highly expressed in the medial PVT, while those involved in the intake of food and drugs of abuse are distributed throughout the PVT. Third, the pattern and content of neuropeptide expression in mice and rats appear not to be identical, and many neuropeptides found in the mouse PVT have not yet been demonstrated in the rat. Thus, while significantly more work is required to uncover the expression patterns and specific roles of individual neuropeptides in the PVT, the evidence thus far supports the existence of a diverse yet highly organized system of neuropeptides in this nucleus. Determined in part by their location within the PVT and their network of projections, the function of the neuropeptides in this system likely involves intricate coordination to influence both affective and motivated behavior.

Do medial sural artery perforator flaps have better clinical outcomes compared to the rectus abdominis perforator (DIEAP) flap in reconstruction of glossectomy defects? A Prisma guided meta-analysis

BACKGROUND

There is an increasing evidence for the use of thin flaps based on vascular perforators for reconstructive surgeries. The medial sural and deep inferior epigastric artery flaps offer versatility for the reconstruction of major defects of the head and neck.

OBJECTIVES

"Whether medial sural artery perforator (MSAP) flap or rectus abdominis perforator flap is better for the reconstruction of glossectomy defects in terms of functional outcome?"

DATA SOURCES

PubMed, Cochrane Library, clinicaltrials.gov and hand searches.

PARTICIPANTS AND INTERVENTIONS

Patients who underwent tongue reconstruction with either MSAP flap or deep inferior epigastric artery perforator (DIEAP) flap.

STUDY APPRAISAL AND SYNTHESIS METHODS

Based on defined study criteria 6 studies were selected according to Prisma Guidelines. The overall estimated effect was categorized as significant where P < 0.05.

RESULTS

There was no significant difference between both flaps in terms of receptor site complications (P = 0.223). Overall odds ratio (OR) for complications was 1.35 (95% confidence interval [CI]: 0.412-0.736) and the test for overall effect t value was 2.836, P < 0.05. Overall OR was 6.01 (95% CI 0.5-7.45) and the test for overall effect t value was 1.41, P < 0.05 indicating there was a statistical difference in the intelligibility of speech.

LIMITATIONS

Anatomical variations, under-reporting of studies and lack of universal tool for speech intelligibility.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Both the flaps are comparable in terms of functional outcome. Medium-sized defects can be reconstructed with MSAP and composite larger defects would benefit from DIEAP. In females, anterolateral thigh flap still remains the choice for composite reconstructions.

Return to Collegiate Athletics After Distal Femoral Osteotomy: A Report of Three Cases and Review of the Literature

BACKGROUND

The authors present three cases of high-level athletes with successful return to competitive collegiate athletics following distal femoral osteotomy for knee lateral compartment overload.

CONCLUSION

Distal femoral varus osteotomy (DFO) is used to treat valgus knee malalignment and to offload the lateral knee compartment in the setting of symptomatic cartilage or meniscus pathology. DFO can be considered a viable treatment for collegiate athletes, with satisfactory outcomes and ability to return to sport participation at pre-injury functional levels.Level of Evidence: IV.

[Anterior cruciate ligament reconstruction with femoral tunnel via medial portal vs trans-tibial]

Anterior cruciate ligament injury (ACL) of the knee is a severe traumatic injury that greatly decreases the function and sometimes leaves very important sequelae for the young patient so surgery for ligament reconstruction is the suitable treatment, there are several techniques for the elaboration of tunnels with difference in the portals, the methods of fixation and the different grafts used and each one of the authors defend their techniques giving their advantages and disadvantages and possible complications associated. The objective of this study was to assess the advantages or not of two approaches to the femoral side for the passage of the graft or implants. Material and methods: Two similar groups in this observational, transversal, retrospective and analytical study in patients operated by the same surgeon and assistants. In a period of time of three year, 80 patients were operated, 42 of them by medial portal and 38 of them via trans tibial. Results: The male sex in both groups was the predominant one, the parameters of ease were assessed to observe the passage of the tendon or graft, the passage of the femoral implant, the ease of the implant grip, the tension of the same and the operative time in both groups. The result was conclusive being an p 0.06 contemplating the best result in patients operated by medial portal.

Quantifying the Center of Elbow Rotation: Implications for Medial Collateral Ligament Reconstruction

BACKGROUND

Medial collateral ligament (MCL) reconstruction of the elbow mandates precise characterization of where the centerline of elbow rotation projects onto the medial epicondyle (ME). A muscle-splitting approach allows the flexor-pronator muscles to remain attached to the ME and facilitates visualization of the MCL remnant, the sublime tubercle, and the ulnohumeral joint line. Knowledge of where the centerline of rotation intersects the ME relative to the ulnohumeral joint line may assist the surgeon during placement of the proximal drill hole.

METHODS

Models were created from the computed tomography scans of 29 normal elbows. The centerline of rotation, center of the trochlea, sublime tubercle, and ulnohumeral joint line were identified. Measurements were taken from the ulnohumeral joint line to the center of the trochlea and to the centerline of rotation in the sagittal view and along the course of the MCL.

RESULTS

The centerline of rotation intersected the ME in a consistent location. With the elbow flexed 90°, the trochlea center and the centerline of rotation are essentially in line with each other. There are significant differences between the distances from the ulnohumeral joint line to the center of the trochlea and to the centerline of rotation in both the sagittal view and along the course of the MCL.

CONCLUSIONS

The centerline of rotation is located 14.31 mm (1.70) from the ulnohumeral joint line in the sagittal view and 16.54 mm (2.09) from the ulnohumeral joint line along the course of the MCL.

Lateral Column Lengthening for Revision Triple and Double Arthrodesis and Severe End-Stage Flatfoot Deformity

Few options exist for the treatment of revision and severe cases of end-stage flatfoot deformity. Triple arthrodesis or medial-approach double arthrodesis have been the standard but often do not provide enough correction of the deformity. Lateral column lengthening is a powerful procedure performed either with an Evans calcaneal osteotomy or calcaneocuboid distraction arthrodesis that can be used as an adjunct in realigning the flatfoot. We performed a retrospective radiographic review and looked at 11 consecutive cases of patients who underwent hindfoot arthrodesis with a lateral column lengthening procedure. We matched these patients with 11 control patients who underwent isolated medial-approach double arthrodesis. For the patients who underwent a lateral column lengthening procedure, we found a significant improvement in calcaneal inclination angle (p = .001) and greater correction in talar declination angle, cuboid abduction angle, and talocalcaneal angle when compared with the control group. Lateral column lengthening is a useful adjunct to hindfoot arthrodesis in the correction of revision and severe end-stage flatfoot deformity.

Radiographic Results of Unicortical Medial Malleolar Fracture Fixation

BACKGROUND:

Medial malleolar fractures commonly occur as part of rotational ankle fractures, which often require surgery. Different fixation techniques exist, including unicortical or bicortical lag-screw fixation. Bicortical screws that engage the lateral distal tibia have been noted to be biomechanically superior to unicortical ones with a lower failure rate. The authors of this study have used unicortical screws routinely. This study was initiated to investigate the clinical results of a large series of patients with unicortical medial malleolar fixation.

METHODS:

Patients who underwent unicortical medial malleolar fracture fixation between 2011 and 2017 were reviewed. In total, 461 ankle fractures were identified with a mean follow-up of 11.4 months (range, 3-57), of which 211 had a medial malleolar fracture. Eight patients were excluded as they did not follow up with the treating surgeons after surgery, leaving 203 patients for evaluation. The primary outcome was radiographic union. Any loss of reduction, complication, or subsequent surgery was recorded. Malunion was defined as greater than 2 mm displacement.

RESULTS:

There were 2 asymptomatic nonunions (1.0%), 1 delayed union that healed using an external bone growth stimulator (0.5%), and 2 malunions of the medial malleolus (1.0%) with 1 asymptomatic. The other patient developed posttraumatic osteoarthritis but has not yet required further surgery. None of these 5 patients required revision medial malleolar surgery. Ultimately, the union rate using unicortical medial malleolar fixation was 99.0% (201/203).

CONCLUSION:

Unicortical fixation of medial malleolar fractures resulted in consistently good healing. Even though biomechanical studies have shown that bicortical screws provide stronger fixation, our clinical results indicate that the need for this stronger fixation may be questionable.

LEVEL OF EVIDENCE:

Level IV, retrospective case series.

Treatment of Chronic Simple Elbow Dislocation by Two Separate Incisions - A Case Report

INTRODUCTION

Chronic elbow dislocation is a highly disabling condition to be treated and to provide a successful functional outcome. Surgical treatment of such conditions might result in persisting instability or stiffness of the elbow joint due to associated shortening and contracture of the soft tissues and articular incongruity. Most of the described open reduction techniques are through an extensile posterior approach which might result in increased post-operative stiffness. We report the treatment of such a case with separate medial and lateral incisions with the excellent functional outcome at 1-year follow-up.

CASE REPORT

A 45-year-old lady with 2-month-old elbow dislocation was planned for open reduction of the joint through two separate incisions, medial and lateral. Surgical details and difficulties faced will be analyzed in this paper. The patient currently has 30-140°flexion with complete pronation-supination movements at 1-year follow-up.

CONCLUSION

Chronic dislocation of the elbow is a highly disabling condition and has a very unpredictable outcome. By combining an understanding in the anatomy and biomechanics of the elbow with a proper surgical technique tailored to the individual patient, it is possible to achieve a functional and painless elbow in the majority of cases. By accessing medial and lateral elbow separately, the morbidity and wound complications of an extensile posterior approach can be reduced and also it has similar, if not better, functional results.

Fixed-bearing medial unicompartmental knee arthroplasty restores neither the medial pivoting behavior nor the ligament forces of the intact knee in passive flexion

Medial unicompartmental knee arthroplasty (UKA) is an accepted treatment for isolated medial osteoarthritis. However, using an improper thickness for the tibial component may contribute to early failure of the prosthesis or disease progression in the unreplaced lateral compartment. Little is known of the effect of insert thickness on both knee kinematics and ligament forces. Therefore, a computational model of the tibiofemoral joint was used to determine how non-conforming, fixed bearing medial UKA affects tibiofemoral kinematics, and tension in the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) during passive knee flexion. Fixed bearing medial UKA could not maintain the medial pivoting that occurred in the intact knee from 0° to 30° of passive flexion. Abnormal anterior-posterior (AP) translations of the femoral condyles relative to the tibia delayed coupled internal tibial rotation, which occurred in the intact knee from 0° to 30° of flexion, but occurred from 30° to 90° of flexion following UKA. Increasing or decreasing tibial insert thickness following medial UKA also failed to restore the medial pivoting behavior of the intact knee despite modulating MCL and ACL forces. Reduced AP constraint in non-conforming medial UKA relative to the intact knee leads to abnormal condylar translations regardless of insert thickness even with intact cruciate and collateral ligaments. This finding suggests that the conformity of the medial compartment as driven by the medial meniscus and articular morphology plays an important role in controlling AP condylar translations in the intact tibiofemoral joint during passive flexion. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1868-1875, 2018.

The effect of humeral tunnel locations on radiographic tunnel changes in baseball players following medial ulnar collateral ligament reconstruction: comparison of anatomic and nonanatomic locations

BACKGROUND

There has been no study on radiologic changes after medial ulnar collateral ligament (MUCL) reconstruction and related clinical features.

METHODS

Data from 39 baseball players who underwent MUCL reconstruction were collected and analyzed. The baseball players were classified into 2 groups according to the starting point of the humeral tunnel: (1) the lower tip of the medial epicondyle (group NA, n = 21) and (2) the remnant of the MUCL (group A, n = 18). Bone tunnel characteristics and changes were evaluated by computed tomography (CT) at 3 and 9 months postoperatively. Outcome measures consisted of the visual analog scale, range of motion (ROM), the Conway scale, and the presence of ulnar nerve irritation postoperatively.

RESULTS

The mean diameter of the humeral entry was 4.0 mm (range, 3.4-5.1 mm) on the first CT scan, which increased to 5.5 mm (range, 3.2-7.2 mm) on the follow-up CT scan (P < .001). The mean diameter of the ulnar tunnel was 2.8 mm (range, 1.1-3.3 mm) on the first CT scan, which decreased to 1.6 mm (range, 0-4.3 mm) on the follow-up CT scan (P < .001). The between-group comparison revealed no differences in the changes in the diameter of the humeral and ulnar tunnels. A statistically significant correlation was not found between athletic performance measured by the Conway scale and the radiologic changes on CT evaluation (P = .182). Group A showed improvement in extension from 7° preoperatively to 1° postoperatively (P < .001) and in flexion from 126° preoperatively to 136° postoperatively (P < .001), while group NA did not achieve statistical significance in ROM improvement after the operation.

CONCLUSIONS

Humeral tunnel widening was commonly observed, while the ulnar tunnel was maintained or became narrowed conversely. The humeral tunnel placements did not affect tunnel changes after the surgical procedure; however, MUCL reconstruction with the anatomic location of the humeral tunnel yielded substantial improvement in elbow ROM.

Pure Medial Elbow Dislocation without Concomitant Fracture in a 10-Year-Old Child

Pediatric elbow dislocations are rare injuries and are often accompanied by concomitant fractures. We report a rare case of medial dislocation of the right elbow without accompanying fracture in a 10.5-year-old boy after fall from a bicycle. After radiographic and magnetic resonance imaging evaluation, closed reduction under general anesthesia was performed and the elbow was immobilized in a posterior above-elbow slab. Elbow mobilization was started after 2 weeks and the posterior slab was discontinued after 4 weeks. At 3 months, the patient had a full range of active elbow flexion extension and pronation supination. At 4-year followup, radiographs show a normal alignment of the elbow with mild changes of heterotopic ossification. We believe that this is the first such case ever reported in literature. Early recognition and prompt diagnosis is the key to achieve a good result.

Meniscal Preservation is Important for the Knee Joint

Native joint preservation has gained importance in recent years. This is mostly to find solutions for limitations of arthroplasty. In the knee joint, the menisci perform critical functions, adding stability during range of motion and efficiently transferring load across the tibiofemoral articulation while protecting the cartilage. The menisci are the most common injury seen by orthopedicians, especially in the younger active patients. Advances in technology and our knowledge on functioning of the knee joint have made meniscus repair an important mode of treatment. This review summarizes the various techniques of meniscus tear repair and also describes biological enhancements of healing.

Preoperative Patellofemoral Chondromalacia is Not a Contraindication for Fixed-Bearing Medial Unicompartmental Knee Arthroplasty

BACKGROUND

Patellofemoral chondromalacia (PFCM) has historically been considered a contraindication for unicompartmental knee arthroplasty (UKA), but there is limited data assessing PFCM's impact on the results of fixed-bearing UKA. Our objective was to assess the impact of medial patellar and/or medial trochlear PFCM on overall and patellofemoral-specific 2-year outcomes after fixed-bearing medial UKA.

METHODS

Intraoperative notes defined the presence and location of PFCM during fixed bearing medial UKA. Outcome measures included the New Knee Society Score (NKSS), Kneeling Ability Score (KAS) and Forgotten Joint Score (FJS-12). Thirty-one knees with PFCM (PFCM group), and 52 knees without PFCM (N-PFCM group) were included for analysis. Mann-Whitney U tests assessed the statistical significance of observed differences, and a Bonferroni correction was applied, adjusting threshold for significance to P = .005.

RESULTS

At minimum follow-up of 2 years, no statistical differences were detected between the N-PFCM and PFCM groups in the postoperative NKSS (159 vs 157, P = .731), preoperative to postoperative NKSS change (P = .447), FJS-12 (70.5 vs 67.6, P = .471), or KAS (71% vs 65%, P = .217). Patients with isolated patellar chondromalacia (n = 13) demonstrated trends toward worse outcomes according to NKSS (147, P = .198), FJS-12 (58, P = .094), and KAS (46%, P = .018), but were statistically insignificant. No failures occurred in either group.

CONCLUSION

Functional outcomes of fixed-bearing medial UKA are not adversely impacted by the presence of PFCM involving the medial patellar facet and/or medial or central trochlea. Further follow-up is needed to determine longer-term implications of fixed-bearing medial UKA in patients with PFCM.

Age Differences in the Prevalence of Isolated Medial and Lateral Meniscal Tears in Surgically Treated Patients

PURPOSE

To compare the prevalence of isolated lateral and medial meniscal tears in different aged populations.

METHODS

A five-year retrospective review for meniscal procedures performed on a total of 782 patients. Each chart was reviewed to document the prevalence of medial or lateral meniscal injuries. Inclusion criteria were patients found to have documented evidence of meniscal tear, either lateral or medial, without any concomitant injuries and/or any other procedures performed. Patients excluded from the study were those with concomitant pathologies, such as chondromalacia, malalignment or ligamentous injuries. Patients were classified by age into three groups: < 20 years, 20-30 years and > 30 years old.

RESULTS

68.7% of patients had medial meniscal tears, (average age 37.6 years), 17.1% of these were isolated medial meniscus injuries (average 31.9 years). 31.3% had lateral meniscal injuries (average 27.7 years). Of these, 18.8 % had isolated lateral meniscal injuries (average 22.8 years). All remaining patients had additional diagnoses/procedures. Isolated medial meniscal injuries were more common in older patients as 48 of the 92 isolated medial tears (52.2%) were found in patients > 30 years of age (p <0.001). Isolated lateral meniscal injuries, on the other hand, were more common in younger patients. 29 of the 46 isolated lateral tears (63%) occurred in patients under 20 years (p = 0.002). Only seven (15.2%) isolated lateral tears were shown in patients older than 30 years.

CONCLUSION

Isolated lateral meniscal tears are more common in patients < 20 years, and decrease with age, while the prevalence of medial meniscal tears increase with age.

The operative outcomes of displaced medial-end clavicle fractures

BACKGROUND

Nonoperative treatment of displaced medial clavicle fractures often leads to poor functional outcomes and painful nonunions. This study investigates the functional outcomes of patients undergoing operative fixation of these fractures.

METHODS

We investigated 27 patients undergoing operative fixation of a medial clavicle fracture; 24 had an acute, displaced fracture and 3 had fixation for nonunions. Preoperative radiographs or computed tomography scans were obtained, and data collected included age, sex, mechanism of injury, and fixation method. Follow-up included physical examination and radiographs for assessment of union; Disabilities of the Arm, Shoulder, and Hand scores at 12 months; and the recording of complications.

RESULTS

The median age was 37 years (interquartile range, 17-47 years). There were 26 male patients and one female patient included, with 7 physeal injuries and 20 adult injuries. The most common mechanism of fracture was vehicular accident (n = 15). Three patients had operations for nonunions and 2 for a periprosthetic fracture medial to an existing plate. The fracture was fixed with plate and screws in 19 cases and with transosseous sutures in 8 cases. The median Disabilities of the Arm, Shoulder, and Hand score at 12 months was 0.4 (interquartile range, 0-5.0), with a union rate of 100% at 12 months. All patients had full shoulder range of motion at final follow-up and were able to return to preinjury occupational activities. There were no significant complications.

CONCLUSION

Operative fixation of displaced medial clavicle fractures results in anatomic reconstruction and excellent functional outcomes, even in the setting of fixation performed for symptomatic nonunion. Early intervention can minimize the risk of painful nonunion.

Graft extrusion in both the coronal and sagittal planes is greater after medial compared with lateral meniscus allograft transplantation but is unrelated to early clinical outcomes

BACKGROUND

Graft extrusion after meniscus allograft transplantation (MAT) may be affected by horn fixation, which differs between medial and lateral MAT. Few studies have compared graft extrusion, especially sagittal extrusion, after medial and lateral MAT.

HYPOTHESIS

In patients undergoing medial and lateral MAT, graft extrusion is likely similar and not correlated with postoperative Lysholm scores.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Meniscus graft extrusion in the coronal and sagittal planes was compared in 51 knees undergoing medial MAT and 84 undergoing lateral MAT. Distances from the anterior and posterior articular cartilage margins to the anterior (anterior cartilage meniscus distance [ACMD]) and posterior (posterior cartilage meniscus distance [PCMD]) horns, respectively, were assessed on immediate postoperative magnetic resonance imaging and compared in patients undergoing medial and lateral MAT. Correlations between coronal and sagittal graft extrusion and between extrusion and the Lysholm score were compared in the 2 groups.

RESULTS

In the coronal plane, mean absolute (4.3 vs 2.7 mm, respectively; P<.001) and relative (39% vs 21%, respectively; P<.001) graft extrusions were significantly greater for medial than lateral MAT. In the sagittal plane, mean absolute and relative ACMD and PCMD values were significantly greater for medial than lateral MAT (P<.001 each). For both medial and lateral MAT, mean absolute and relative ACMDs were significantly larger than PCMDs (P<.001 each). Graft extrusion>3 mm in the coronal plane was significantly more frequent in the medial (78%) than in the lateral (35%) MAT group. In the sagittal plane, the frequencies of ACMDs (72% vs 39%, respectively) and PCMDs (23% vs 4%, respectively) >3 mm were also significantly greater in the medial than in the lateral MAT group. Coronal and sagittal extrusions were not correlated with postoperative Lysholm scores for both medial and lateral MAT.

CONCLUSION

The amount and incidence of graft extrusion were greater after medial than lateral MAT in both the coronal and sagittal planes. In the sagittal plane, graft extrusion was greater and more frequent on the anterior than the posterior horn in both medial and lateral MAT. However, graft extrusion was not correlated with early clinical outcomes after both medial and lateral MAT.

Medial amygdala lesions selectively block aversive pavlovian-instrumental transfer in rats

Pavlovian conditioned stimuli (CSs) play an important role in the reinforcement and motivation of instrumental active avoidance (AA). Conditioned threats can also invigorate ongoing AA responding [aversive Pavlovian-instrumental transfer (PIT)]. The neural circuits mediating AA are poorly understood, although lesion studies suggest that lateral, basal, and central amygdala nuclei, as well as infralimbic prefrontal cortex, make key, and sometimes opposing, contributions. We recently completed an extensive analysis of brain c-Fos expression in good vs. poor avoiders following an AA test (Martinez et al., 2013, Learning and Memory). This analysis identified medial amygdala (MeA) as a potentially important region for Pavlovian motivation of instrumental actions. MeA is known to mediate defensive responding to innate threats as well as social behaviors, but its role in mediating aversive Pavlovian-instrumental interactions is unknown. We evaluated the effect of MeA lesions on Pavlovian conditioning, Sidman two-way AA conditioning (shuttling) and aversive PIT in rats. Mild footshocks served as the unconditioned stimulus in all conditioning phases. MeA lesions had no effect on AA but blocked the expression of aversive PIT and 22 kHz ultrasonic vocalizations in the AA context. Interestingly, MeA lesions failed to affect Pavlovian freezing to discrete threats but reduced freezing to contextual threats when assessed outside of the AA chamber. These findings differentiate MeA from lateral and central amygdala, as lesions of these nuclei disrupt Pavlovian freezing and aversive PIT, but have opposite effects on AA performance. Taken together, these results suggest that MeA plays a selective role in the motivation of instrumental avoidance by general or uncertain Pavlovian threats.

Tendinopathies Around the Elbow Part 2: Medial Elbow, Distal Biceps and Triceps Tendinopathies

In the second part of this review article the management of medial elbow tendinopathy, distal biceps and distal triceps tendinopathy will be discussed. There is a scarcity of publications concerning any of these tendinopathies. This review will summarise the current best available evidence in their management. Medial elbow tendinopathy, also known as Golfer's elbow, is up to 6 times less common than lateral elbow tendinopathy. The tendinopathy occurs in the insertion of pronator teres and flexor carpi radialis. Diagnosis is usually apparent through a detailed history and examination but care must be made to exclude other conditions affecting the ulnar nerve or less commonly the ulnar collateral ligament complex. If doubt exists then MRI/US and electrophysiology can be used. Treatment follows a similar pattern to that of lateral elbow tendinopathy. Acute management is with activity modification and topical NSAIDs. Injection therapy and surgical excision are utilised for recalcitrant cases. Distal biceps and triceps tendinopathies are very rare and there is limited evidence published. Sequelae of tendinopathy include tendon rupture and so it is vital to manage these tendinopathies appropriately in order to minimise this significant complication. Their management and that of partial tears will be considered.

Medial or lateral location of the whirlpool sign in adnexal torsion: clinical importance

OBJECTIVES

The whirlpool sign is used as a sonographic marker for adnexal torsion. The aims of this study were to describe the location of the whirlpool sign (lateral or medial to the ovary) and to evaluate the clinical importance of the location.

METHODS

Thirty patients with a confirmed surgical diagnosis of torsion and a positive whirlpool sign on sonography before surgery were included. We examined the sonographic clips of these patients. Classic signs of adnexal torsion were determined: ovarian edema, the presence of a mass, pelvic free fluid, and ovarian ischemia on Doppler imaging. The whirlpool sign was detected on grayscale and color Doppler sonography by moving the transducer to and fro along the axis of suspected torsion.

RESULTS

Sixteen of 30 patients had right-sided torsion. Of these, 7 had a lateral whirlpool sign. All 7 of these patients had an ovarian or paraovarian mass. Nine of these 16 patients had a medial whirlpool sign. Of these, 7 had an ovarian or paraovarian mass, and 2 had no mass. Of the 14 patients with left-sided torsion, all had a medial whirlpool sign. Nine of 14 these patients had an ovarian or paraovarian mass, and 5 had no mass. The mean volume of the masses among cases with the lateral whirlpool sign was significantly greater compared to those with the medial whirlpool sign (304 versus 108 cm(3); P = .035). In 25 of 30 cases, the torsed components included the ovary.

CONCLUSIONS

The lateral whirlpool sign is associated with enlarged masses in comparison to the medial whirlpool sign. This finding indicates the need to search meticulously for the lateral whirlpool sign in cases with enlarged masses to decide whether to operate on these patients emergently.

Simple medial elbow dislocations: a rare injury at risk for early instability

PURPOSE

To report the presentation, treatment, and outcomes of a series of simple medial elbow dislocations and to identify features distinguishing this injury from the more common dislocation patterns.

METHODS

From 2000 to 2011, 4 cases of simple medial elbow dislocations were treated at a single referral center. Retrospective review was conducted to evaluate presentation, treatment, and outcomes.

RESULTS

The mean patient age was 56 years (range, 49-61 y). All dislocations were in the nondominant arm of women after a fall from standing height. Two elbows had immediate closed reduction, and 2 elbows could not be reduced acutely. All elbows presented within 2.5 weeks of injury with recurrent instability or dislocation. Two patients also had acute symptoms of ulnar neuropathy. All patients had surgical repair of the lateral collateral ligament complex and extensor tendon origin. Three patients had ulnar nerve decompressions. All elbows were stable to valgus, varus, and rotatory stress testing, with no subjective instability at a minimum follow-up of 8 months (range, 8-144 mo). Three patients reported no pain. Symptoms of ulnar neuropathy resolved in all patients. Mean elbow range of motion was from 13° to 135° of extension/flexion, with full pronation and supination.

CONCLUSIONS

Simple medial elbow dislocations may be at risk for early instability and may represent a more noteworthy soft tissue injury than typical dislocation patterns. Surgical treatment of early instability in these injuries led to acceptable patient outcomes.

The KineSpring(®) Knee Implant System: an implantable joint-unloading prosthesis for treatment of medial knee osteoarthritis

Symptomatic medial compartment knee osteoarthritis (OA) is the leading cause of musculoskeletal pain and disability in adults. Therapies intended to unload the medial knee compartment have yielded unsatisfactory results due to low patient compliance with conservative treatments and high complication rates with surgical options. There is no widely available joint-unloading treatment for medial knee OA that offers clinically important symptom alleviation, low complication risk, and high patient acceptance. The KineSpring^® Knee Implant System (Moximed, Inc, Hayward, CA, USA) is a first-of-its-kind, implantable, extra-articular, extra-capsular prosthesis intended to alleviate knee OA-related symptoms by reducing medial knee compartment loading while overcoming the limitations of traditional joint-unloading therapies. Preclinical and clinical studies have demonstrated excellent prosthesis durability, substantial reductions in medial compartment and total joint loads, and clinically important improvements in OA-related pain and function. The purpose of this report is to describe the KineSpring System, including implant characteristics, principles of operation, indications for use, patient selection criteria, surgical technique, postoperative care, preclinical testing, and clinical experience. The KineSpring System has potential to bridge the gap between ineffective conservative treatments and irreversible surgical interventions for medial compartment knee OA.