A Radiographic Sizing Algorithm for Tibial Plateau Osteochondral Allografts

OBJECTIVE

Tibial plateau osteochondral allograft transplantation is a promising treatment for symptomatic chondral damage of the proximal tibia due to a variety of etiologies. The purpose of this investigation is to develop an accurate and reproducible algorithm for sizing tibial plateau allografts based on recipient radiographs.

DESIGN

A cadaveric study was performed in which radiographs of 10 fresh frozen cadaveric knees were compared to measured digital photographs of the disarticulated specimens. By comparing the average distance between standard anatomical landmarks on the radiographs to the gross specimens, a correlation factor was calculated that could be applied to recipient radiograph measurements for more accurate sizing of tibial plateau allografts.

RESULTS

In the coronal plane there were no differences between the mean radiographic and mean morphologic measurements of either the medial or lateral tibial plateau. However, in the sagittal plane the anatomic specimens of the medial and lateral plateau were 90% and 80%, respectively, of the measurements made from the lateral radiograph.

CONCLUSIONS

This cadaveric investigation is the first to propose a sizing algorithm for tibial plateau osteochondral allografts. Based on the results, an anteroposterior radiograph can reliably measure the width of both the medial and lateral tibial plateau without any correction needed. The average morphological lengths of the medial and lateral tibial plateau, on the other hand, were found to be 90% and 80%, respectively, of the radiographically measured lengths. Without correction, this would lead to the implantation of oversized grafts that may contribute to early failure.

Surgeon Agreement on the Presence of Pathologic Anterior Instability on Shoulder Imaging Studies

Background

In the setting of anterior shoulder instability, it is important to assess the reliability of orthopaedic surgeons to diagnose pathologic characteristics on the 2 most common imaging modalities used in clinical practice: standard plain radiographs and magnetic resonance imaging (MRI).

Purpose

To assess the intra- and interrater reliability of diagnosing pathologic characteristics associated with anterior shoulder instability using standard plain radiographs and MRI.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

Patient charts at a single academic institution were reviewed for anterior shoulder instability injuries. The study included 40 sets of images (20 radiograph sets, 20 MRI series). The images, along with standardized evaluation forms, were distributed to 22 shoulder/sports medicine fellowship-trained orthopaedic surgeons over 2 points in time. Kappa values for inter- and intrarater reliability were calculated.

Results

The overall response rate was 91%. For shoulder radiographs, interrater agreement was fair to moderate for the presence of glenoid lesions (κ = 0.49), estimate of glenoid lesion surface area (κ = 0.59), presence of a Hill-Sachs lesion (κ = 0.35), and estimate of Hill-Sachs surface area (κ = 0.50). Intrarater agreement was moderate for radiographs (κ = 0.48-0.57). For shoulder MRI, interrater agreement was fair to moderate for the presence of glenoid lesions (κ = 0.44), glenoid lesion surface area (κ = 0.35), Hill-Sachs lesion (κ = 0.33), Hill-Sachs surface area (κ = 0.28), humeral head edema (κ = 0.41), and presence of a capsulolabral injury (κ = 0.36). Fair agreement was found for specific type of capsulolabral injury (κ = 0.21). Intrarater agreement for shoulder MRI was moderate for the presence of glenoid lesion (κ = 0.59), presence of a Hill-Sachs lesion (κ = 0.52), estimate of Hill-Sachs surface area (κ = 0.50), humeral head edema (κ = 0.51), and presence of a capsulolabral injury (κ = 0.53), and agreement was substantial for glenoid lesion surface area (κ = 0.63). Intrarater agreement was fair for determining the specific type of capsulolabral injury (κ = 0.38).

Conclusion

Fair to moderate agreement by surgeons was found when evaluating imaging studies for anterior shoulder instability. Agreement was similar for identifying pathologic characteristics on radiographs and MRI. There was a trend toward better agreement for the presence of glenoid-sided injury. The lowest agreement was observed for specific capsulolabral injuries.

Synthetic Turf: History, Design, Maintenance, and Athlete Safety

CONTEXT:

Synthetic turf has become an increasingly common playing surface for athletics and has changed dramatically since its introduction more than 50 years ago. Along with changes to surface design, maintenance needs and recommendations have become more standardized and attentive both to upkeep and player-level factors. In particular, synthetic turf maintenance as it relates to athlete health and safety is an important consideration at all levels of play.

EVIDENCE ACQUISITION:

A literature search of MEDLINE and PubMed for publications between the years 1990 and 2018 was conducted. Keywords included s ynthetic turf, artificial turf, field turf, and playing surface. Additionally, expert opinion through systematic interviews and practical implementation were obtained on synthetic turf design and maintenance practices in the National Football League.

STUDY DESIGN:

Clinical review.

LEVEL OF EVIDENCE:

Level 5.

RESULTS:

Synthetic turf has changed considerably since its inception. Playing surface is a critical component of the athletic environment, playing a role both in performance and in athlete safety. There are several important structural considerations of third-generation synthetic turf systems currently used in the United States that rely heavily on strong and consistent maintenance. A common misconception is that synthetic turf is maintenance free; in fact, however, these surfaces require routine maintenance. Whether athletes experience more injuries on synthetic over natural surfaces is also of interest among various levels and types of sport.

CONCLUSION:

Modern synthetic turf is far different than when originally introduced. It requires routine maintenance, even at the level of local athletics. It is important for sports medicine personnel to be familiar with playing surface issues as they are often treating athletes at the time of injury and should maintain a level of awareness of contemporary research and practices regarding the relationships between synthetic turf and injury.

Fatigue Bending Strength of Jones Fracture Specific Screw Fixation

BACKGROUND

Intramedullary screw fixation is a common method of treating proximal metadiaphyseal fifth metatarsal (ie, Jones) fractures. Fatigue failure is a complication of this fixation. There are many screw designs available, including Jones fracture specific fixation, but the optimal choice of screw design is unknown. The purpose of this study was to compare the fatigue strength of Jones fracture specific screw designs as well as other commonly used screw designs. Our hypothesis was that there would be no difference in fatigue strength for Jones fracture specific screw designs at similar screw diameters.

METHODS

A study was performed to determine the fatigue bending strength of 5 different screw designs including Jones fracture specific screw designs at 3 different screw diameters. Six screws of each size and design underwent cyclic fatigue testing, and a median fatigue limit (MFL) was determined for each screw design and size.

RESULTS

The Stryker Asnis JFX solid 4.0-mm, 5.0-mm, and 6.0-mm screws had a higher MFL than all other screws with similar diameter tested (all P < .0001). Both Jones fracture specific screw designs (Stryker Asnis JFX solid screws and Charlotte Carolina Jones screws) had higher MFLs than the other screw designs tested.

CONCLUSION

This study provides comparative fatigue strength data on larger screw diameters, which have not been previously reported. There was a statistically significant difference in screw fatigue properties at the screw diameters tested.

CLINICAL RELEVANCE

The clinical significance of this study is that it provides surgeons with fatigue strength data to aid in screw selection for Jones fracture fixation.

The Athletic Shoe in Football

BACKGROUND

Foot and ankle injuries are common in sports, particularly in cleated athletes. Traditionally, the athletic shoe has not been regarded as a piece of protective equipment but rather as a part of the uniform, with a primary focus on performance and subjective feedback measures of comfort. Changes in turf and shoe design have poorly understood implications on the health and safety of players.

EVIDENCE ACQUISITION

A literature search of the MEDLINE and PubMed databases was conducted. Keywords included athletic shoewear, cleated shoe, football shoes, and shoewear, and search parameters were between the years 2000 and 2016.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

The athletic shoe is an important piece of protective sports equipment. There are several important structural considerations of shoe design, including biomechanical compliance, cleat and turf interaction, and shoe sizing/fit, that affect the way an athlete engages with the playing surface and carry important potential implications regarding player safety if not understood and addressed.

CONCLUSION

Athletic footwear should be considered an integral piece of protective equipment rather than simply an extension of the uniform apparel. More research is needed to define optimal shoe sizing, the effect that design has on mechanical load, and how cleat properties, including pattern and structure, interact with the variety of playing surfaces.

Correction of Hammertoe Deformity With Novel Intramedullary PIP Fusion Device Versus K-Wire Fixation

BACKGROUND

K-wire fixation has been the most common method of fixation for hammertoe deformity. However intramedullary devices are gaining ground in both number of available choices and in procedures performed. This study aimed to compare the outcomes of hammertoe correction performed with K-wire fixation versus a novel intramedullary fusion device (CannuLink).

METHODS

A retrospective review of hammertoe correction by a single surgeon was performed from June 2011 to December 2013. Sixty patients (95 toes) underwent K-wire fixation and 39 patients (54 toes) underwent fusion with the CannuLink implant. Average age was 61.7 years and 61.4 years, respectively. Average length of follow-up was 12.9 and 12.3 months, respectively. Patients were evaluated for medical comorbidities, smoking status, inflammatory arthritis, peripheral vascular disease, peripheral neuropathy, pre- and postoperative visual analog pain scale, bony union percentage, revision rate, complications (hardware and surgery-related), and persistent symptoms at last follow-up. There was no significant difference in demographics or comorbidities between the 2 groups ( P > .05).

RESULTS

In the K-wire group, 16 patients (18 toes) remained symptomatic at last follow-up (27%). Nine toes (9.5%) had recurrent deformity, 3 toes (3%) developed a late infection because of the recurrent deformity, and 1 toe (1%) developed partial numbness. One patient suffered a calf deep vein thrombosis (DVT) and peroneal nerve neuritis, 1 patient developed foot drop, and 3 patients continued to complain of pain. Five toes required revision surgery (5.3%). In the intramedullary group, 3 (7.7%) patients remained symptomatic and all were associated with a complication. One patient developed chronic regional pain syndrome in the foot, a calf DVT, and a nonfatal pulmonary embolus. A second patient developed a painless recurrent deformity. A third patient had wound dehiscence. Nobody had hardware failure or required a second operation.

CONCLUSION

The CannuLink intramedullary device for hammertoe correction resulted in fewer complications, only 1 recurrent deformity, and no reoperations compared with K-wire fixation.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Etiology and Biomechanics of Midfoot (Lisfranc) Injuries in Athletes

Tarsometatarsal (TMT) dislocations are an uncommon but debilitating athletic injury. When symptomatic midfoot instability persists, an injured athlete frequently requires surgical stabilization and rehabilitation for up to 9 months before returning to full athletic participation. Unfortunately, the limited biomechanical knowledge of this injury prevents prophylactic measures from being developed that could reduce an athlete's risk of injury. The goal of this article is to summarize the literature on TMT dislocations, with a particular emphasis on the relevant biomechanics, in an attempt to clarify the circumstances and mechanisms under which these injuries occur. Since athletic injuries represent only a small portion of all TMT dislocations, other categories of injuries are also considered for the insight they provide. This review first summarizes the anatomy of the TMT joint as well as the clinical details surrounding TMT dislocations. The various hypothesized injury mechanisms are then reviewed with particular attention given to cadaveric studies that investigate these mechanisms. Based on this critical review, gaps in the research related to epidemiologic data, full-scale and component testing, numerical modeling, and countermeasure development, are identified. Only by improving our understanding of the causes and biomechanics can steps be taken to protect athletes from these injuries.

Mini-open repair of achilles rupture in the national football league

Tears of the Achilles tendon in professional athletes are an infrequent yet devastating injury. Historical studies have demonstrated not only a poor rate of return to competitive play but have also noted significant declines in performance for those able to return. While classic treatment of these injuries in the competitive athlete has been an open, locked suture repair, this article reports on a consecutive series of professional football athletes who underwent mini-open repair. All athletes returned to professional football, with seven out of nine (78%) returning to National Football League (NFL) competition. Average return to play was 273 days (8.9 months), with one athlete returning at 166 days (5.4 months). There have been no reruptures and no sural nerve or wound healing complications. Although limited in number currently, mini-open repair in NFL athletes has allowed successful return to competitive play with no reruptures and a trend toward faster return to play compared with historical open repair outcomes.

Biomechanical evaluation of physeal-sparing fixation methods in tibial eminence fractures

BACKGROUND

Tibial eminence fractures occur most commonly in skeletally immature children. Several techniques using physeal-sparing fracture fixation have been described, but their structural properties have not been evaluated.

PURPOSE

To determine the strength and resistance to displacement of physeal-sparing techniques used to fix tibial eminence fractures.

STUDY DESIGN

Controlled laboratory study.

METHODS

Skeletally immature porcine knees were randomized into 4 treatment groups: (1) ultra-high molecular weight polyethylene suture-suture button (UHMWPE/SB), (2) suture anchor, (3) polydioxanone suture-suture button (PDS/SB), and (4) screw fixation. A prospective analysis of bone mineral density using dual-energy x-ray absorptiometry was performed on all specimens. Fracture fragments were created in a standardized manner and measured for size comparison. After fracture fixation, biomechanical testing was performed with cyclical and load-to-failure protocols by loading the tibia with an anterior shear force.

RESULTS

In load-to-failure testing, screw fixation had a significantly lower median peak failure load (186.4 N; lower quartile [LQ], 158.4 N; upper quartile [UQ], 232.6 N) than did UHMWPE/SB (465.8 N; LQ, 397.8 N; UQ, 527.8 N), suture anchors (440.5 N; LQ, 323.0 N; UQ, 562.3 N), and PDS/SB (404.3 N; LQ, 385.9 N; UQ, 415.6 N). UHMWPE/SB demonstrated a significantly higher median yield load (465.8 N; LQ, 397.8 N; UQ, 527.8 N) than did PDS/SB (306.7 N; LQ, 271.4, N; UQ, 405.7 N) and screw fixation (179.0 N; LQ, 120.2 N; UQ, 232.5 N). During cyclical testing, screw fixation demonstrated significantly lower percentage survival of specimens (0%) compared with the other groups (UHMWPE/SB, 100%; suture anchor, 78%; PDS/SB, 78%). After 1000 cycles of loading, PDS/SB fixation had significantly more median creep (6.76 mm; LQ, 6.34 mm; UQ, 8.28 mm) than did UHMWPE/SB (4.43 mm; LQ, 3.80 mm; UQ, 4.73 mm) and suture anchor fixation (3.06 mm; LQ, 2.59 mm; UQ, 4.28 mm). The lowest median stiffness was observed in the PDS/SB group (48.6 N/mm; LQ, 45.3 N/mm; UQ, 54.2 N/mm). UHMWPE/SB fixation demonstrated a significantly higher median peak failure load after cyclic testing (469.0 N; LQ, 380.6 N; UQ, 507.2 N) than did PDS/SB (237.7 N; LQ, 197.3 N; UQ, 298.3 N) and screw fixation (132.4 N; LQ, 123.7 N; UQ, 180.9 N). Suture anchor fixation had significantly more variance, as demonstrated by width of interquartile range, in peak failure load, yield load, and creep than did other techniques.

CONCLUSION

Physeal-sparing fixation of tibial eminence fractures with UHMWPE suture-suture button is biomechanically superior to both PDS suture-suture button and a single screw at the time of surgery and provides more consistent fixation than do suture anchors.

CLINICAL RELEVANCE

Suture anchors provide inconsistent fixation for tibial eminence fractures.

Glucagon and GLP-1 inhibit food intake and increase c-fos expression in similar appetite regulating centres in the brainstem and amygdala

BACKGROUND

Glucagon and glucagon-like peptide-1 (GLP-1) are evolutionarily related anorectic hormones. Glucagon also increases energy expenditure. The combination of glucagon and GLP-1 could cause weight loss through a simultaneous reduction in food intake and increased energy expenditure. However, the effect of combined administration of glucagon and GLP-1 on food intake and neuronal activation has not previously been studied. Furthermore, the effect of glucagon on neuronal activation in appetite regulating centres has not been assessed. Characterisation of the effects of glucagon when administered singly and in combination with GLP-1 on neuronal activation will be important for determining the mechanism of action of related potential antiobesity therapies.

OBJECTIVES

To investigate the effects of peripherally administered GLP-1 and glucagon on food intake, neuronal activation and blood glucose in mice when administered individually and in combination.

METHODOLOGY

Food intake, blood glucose and c-fos expression in the hypothalamus, amygdala and brainstem were measured in response to GLP-1 and glucagon, alone and in combination.

RESULTS

Peripherally administered GLP-1 and glucagon decreased food intake and increased c-fos expression in the brainstem and amygdala. Doses of GLP-1 and glucagon that individually did not significantly affect feeding, in combination were anorectic and stimulated neuronal activation in the area postrema (AP) and central nucleus of the amygdala. Combined administration of GLP-1 and glucagon prevented the acute hyperglycemic effect of glucagon alone.

CONCLUSION

Anorectic doses of glucagon and GLP-1 induced similar patterns of c-fos expression. Combined administration of low dose GLP-1 and glucagon inhibited food intake and induced c-fos expression in the AP and amygdala. The combination of both hormones may offer the opportunity to utilise the beneficial effects of reduced food intake and increased energy expenditure, and may therefore be a potential treatment for obesity.

Return to high school- and college-level football after anterior cruciate ligament reconstruction: a Multicenter Orthopaedic Outcomes Network (MOON) cohort study

BACKGROUND

There is a relative paucity of data regarding the effect of anterior cruciate ligament (ACL) reconstruction on the ability of American high school and collegiate football players to return to play at the same level of competition as before their injury or to progress to play at the next level of competition.

PURPOSE

(1) To identify the percentage of high school and collegiate American football players who successfully returned to play at their previous level of competition, (2) to investigate self-reported performance for those players able to return to play or reason(s) for not returning to play, and (3) to elucidate risk factors responsible for players not being able to return to play or not returning to the same level of performance.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study was a retrospective analysis of prospective patients taken from the Multicenter Orthopaedic Outcomes Network (MOON) cohort who identified football as their primary or secondary sport. Identified patients were then questioned in a structured interview regarding their ACL injury, participation in football before their injury, and factors associated with returning to play. Data were analyzed for player position, concurrent meniscal/ligamentous/chondral injury, surgical technique and graft used for ACL reconstruction, and issues pertaining to timing and ability to return to play.

RESULTS

One hundred forty-seven players (including 68 high school and 26 collegiate) met our criteria and were contacted from the 2002 and 2003 MOON cohorts. Return to play rates for all high school and collegiate athletes were similar (63% and 69%, respectively). Based on player perception, 43% of the players were able to return to play at the same self-described performance level. Approximately 27% felt they did not perform at a level attained before their ACL tear, and 30% were unable to return to play at all. Although two thirds of players reported some "other interest" contributing to their decision not to return, at both levels of competition, fear of reinjury or further damage was cited by approximately 50% of the players who did not return to play. Analysis of patient-reported outcome scores at a minimum of 2 years after surgery between patients who returned to play and those who did not demonstrated clinically and statistically significant differences in the International Knee Documentation Committee form, Marx Activity Scale, and Knee injury and Osteoarthritis Outcome Score knee-related quality of life subscale in the collegiate players. Similar clinical differences were not statistically significant in the high school students. Player position did not have a statistically significant effect on the ability to return to play for high school players, and 41% of "skilled" position players and 50% of "nonskilled" position players were able to return to play at the same performance level.

CONCLUSION

Return to play percentages for amateur American football players after ACL reconstruction are not as high as would be expected. While technical aspects of ACL reconstruction and the ensuing rehabilitation have been studied extensively, the psychological factors (primarily a fear of reinjury) influencing the ability to return to play after ACL surgery may be underestimated as a critical factor responsible for athletes not returning to play at any level of competition.

Immunohistochemical localization of bone morphogenetic proteins (BMPs) 2, 4, 6, and 7 during induced heterotopic bone formation

The distribution and staining intensity of bone morphogenetic proteins (BMPs) 2, 4, 6, and 7 were assessed by immunohistochemistry in ectopic bone induced in Nu/Nu mice by Saos-2 cell derived implants. Devitalized Saos-2 cells or their extracts can induce endochondral bone formation when implanted subcutaneously into Nu/Nu mice. BMP staining was mostly cytoplasmic. The most intense BMP staining was seen in hypertrophic and apoptotic chondrocytes, osteoprogenitor cells such as periosteal and perivascular cells, and osteoblasts. BMP staining in osteocytes and osteoclasts was variable, ranging from undetectable to intensely stained, and from minimal to moderately stained in megakaryocytes of the induced bone marrow. BMP-2, 4, 6, and 7 staining in Saos-2 implant-induced bone indicates the following: (1) Saos-2 cell products promote expression of BMPs by host osteoprogenitor cells, which in turn, leads to bone and marrow formation at ectopic sites; (2) strong BMP staining is seen in maturing chondrocytes, and thus may play a role in chondrocyte differentiation and/or apoptosis; (3) BMP expression in perivascular and periosteal cells indicates that osteoprogenitor cells also express BMP; (4) BMP release by osteoclasts may promote osteoblastic differentiation at sites of bone remodeling. These new data can be useful in understanding the role of BMPs in promoting clinical bone repair and in various pathologic conditions.

Analysis of native collagen monomers and oligomers by size-exclusion high-performance liquid chromatography and its application

Collagen extracted from tissues by pepsin digestion is a mixture of monomeric and oligomeric molecules. The oligomers are held together by covalent crosslinks between molecules. A simple size-exclusion high-performance liquid chromatography (HPLC) method for separation of collagen monomers and oligomers using a Bio-Gel TSK 60XL column has been developed for type I collagen from calf skin. Factors influencing the resolution include flow rate, the protein concentration of the sample, and the injection volume. To overcome electrostatic interactions between the protein and the column packing, addition of sodium chloride to the mobile phase was required to recover protein from the HPLC column when using 5 mM acetic acid as the mobile phase. Optimum recovery and oligomer content were obtained at 0.25 M NaCl. Component peaks eluting from the column were identified as monomers and oligomers by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Application of the method showed that increasing the oligomer content of collagen preparations accelerated fibrillogenesis in vitro and decreased the ultimate fibril size produced. Also during fibrillogenesis, collagen oligomers were preferentially incorporated into fibrils, leaving only monomeric collagen in the soluble supernatant fraction. The assay was also shown to be useful for measurement of conversion of monomers to oligomers during accelerated aging of collagen fibrils at 30 degrees C in vitro.