[Recreational and competitive alpine skiing. Typical injury patterns and possibilities for prevention]

A Systematic Review and Meta-analysis of Risk Factors for an Infection After Anterior Cruciate Ligament Reconstruction

Background

Identifying risk factors for an infection after anterior cruciate ligament reconstruction (ACLR) and following targeted preventive strategies can effectively reduce this potentially serious complication.

Purpose

To perform a systematic review and meta-analysis to identify the risk factors for an infection after ACLR.

Study Design

Systematic review; Level of evidence, 4.

Methods

The PubMed, Embase, and Web of Science databases were searched from inception to September 1, 2022, for prospective and retrospective studies investigating risk factors for any type of infection after ACLR. Odds ratios (ORs) or mean differences were calculated for potential risk factors if ≥2 studies assessed the same risk factor. A qualitative analysis of variables was performed if a meta-analysis could not be conducted.

Results

A total of 17 studies with 141,991 patients were included in this review. The overall pooled infection rate was 0.86% (range, 0.24%-5.50%). There were 20 risk factors identified for analysis. Of these, 7 variables independently increased the odds of an infection after ACLR: (1) male sex (OR, 1.90 [95% CI, 1.33-2.73]), (2) diabetes (OR, 2.69 [95% CI, 1.66-4.35]), (3) hamstring tendon autograft (OR, 2.51 [95% CI, 2.03-3.10]), (4) revision ACLR (OR, 2.31 [95% CI, 1.22-4.37]), (5) professional athlete status (OR, 6.21 [95% CI, 1.03-37.38]), (6) lateral tenodesis (OR, 3.45 [95% CI, 1.63-7.28]), and (7) corticosteroid use (OR, 7.83 [95% CI, 3.68-16.63]). No significant associations were found between postoperative infections and age, body mass index, smoking, meniscal repair, or outpatient surgery.

Conclusion

This review revealed that an increased risk of infections after ACLR was associated with male sex, diabetes, hamstring tendon autograft, revision surgery, professional athlete status, lateral tenodesis, and steroid use. Knowledge of the risk factors associated with an infection after ACLR may facilitate the identification of high-risk cases and the implementation of preventive measures to mitigate the serious consequences of this complication.

[Winter sports injuries of the thoracic and lumbar spine : Etiology, classification and stage-specific therapy]

BACKGROUND

Overall, spinal injuries in winter sports are extremely rare. The incidence is given as approximately 0.01/1000 ski days. While falls and collisions at high speed are the main concerns for skiers, spinal injuries for snowboarders occur primarily on landing after a jump. The age of a typical spinally injured skier is 40, which is older than that of the average snowboarder at 23.

CLASSIFICATION

Primarily, the thoracolumbar junction is injured and hereby mainly anterior compression fractures (type A1) and burst fractures (types A3 and A4) occur. Injuries caused by flexion or distraction mechanisms (Type B) or rotation injuries (Type C) are less common. Injuries to the cervical spine are rare overall, but they are also represented in the very few cases with neurological deficits.

THERAPY

With appropriate X‑ray diagnostics, including CT and, if necessary, MRI, the appropriate therapy can be initiated so that a return to sport is possible in most cases. Furthermore, there is ongoing scientific discussion as to when conservative therapy is superior and when surgery is superior.

[Comparison of acute sports injury between recreational skiers and skiers]

OBJECTIVE

To compare and analyze the difference between the injuries of recreational skiers in public ski resorts and those of skiing athletes in official competitions, and to explore the suggestions of medical insurance for these two types of skiers.

METHODS

The injury data of recreational skiers in Chongli District, Zhangjiakou City, Hebei Province during 2018-2019 and 2019-2020 snow seasons, and the injury data of skiers in two official international skiing competitions during 2019-2020 snow season and domestic test events in Chongli District of 2021 Winter Olympic Games were analyzed retrospectively, and the similarities and differences were compared.

RESULTS

A total of 1 187 injuries occurred to recreational skiers in the two public ski resorts during the 2018-2019 snow season, with an injury rate of 0.3%.There were 1 277 injury sites in total, and the most frequent injury sites were head and neck (230 cases, 18.0%), followed by knee joint (204 cases, 16.0%) and lower extremity (131 cases, 10.3%). Thirty-one skiers were injured in the two official international skiing competitions in the 2019-2020 and 2020-2021 snow season, and in the domestic test competitions in the 2021 Winter Olympic Games, and the injury rates were 11.5%, 17.2% and 12.0%, respectively. There were 37 injury sites in total, among which 11 (29.7%) were in the head and neck, followed by 6 (16.2%) in the knee joint and 5 (13.6%) in the chest, rib and abdomen.

CONCLUSION

In order to better guarantee the safety of skiers and timely provide corresponding medical help, safety facilities and technical guidance should be added to the snow resort for leisure skiing, and medical stations should be set up in the snow resort. As the formal ski racing for skiing athletes during the game has 30 to 80 times higher injury ratesthan recreational skiers, and compared with the recreational skiing, head and neck injury rate is higher, and the damage is much heavier, more complete first aid facilities and experienced medical workers are, needed so the field should be equipped with the circuit inside the quantities, track fixed outside the clinic, surrounding referral hospitals set up trauma centers to provide athletes with more timely medical care.

Ski- and snowboard related open peroneal nerve injury: A 20-year retrospective case series study

Introduction

Traumatic peroneal nerve injury (PNI) caused by ski or snowboard edges is a severe but scarcely reported accident.

Methods

In a 20-year retrospective study, all skiers and snowboarders with this injury treated surgically at the Department of Plastic, Reconstructive and Aesthetic Surgery at the Medical University of Innsbruck, Austria, were included, covering a period from 1999/2000 to 2018/2019.

Results

In total, 34 patients were included in this study (30 males (88.2%) and 4 (11.8%) females). Of these 34 injured skiers or snowboarders, 33 (97.1%) were recreational athletes and Non-Austrian citizens, and 21 (61.8%) patients sustained accidental injuries without collision. All of the injuries under investigation, i.e., open lacerations, most often with complete transection, were the patients’ main injuries. Surgery was performed with direct coaptation in 24 patients (70.6%), and with a suralis nerve graft in the other 10 patients (29.4%).

Conclusion

Traumatic laceration of the peroneal nerve at the knee level by sharp ski or snowboard edges is a rare but severe injury. Causes for this injury may be multifactorial. Recommendations to reduce the risk of such an injury may follow general instructions and warnings to skiers and snowboarders regarding equipment, familiarity with the region, as well as appropriate skills and training.

•

In accidents of skiers and snowboarders traumatic laceration of the peroneal nerve is a severe, but rare injury.

•

This injury type is rarely reported.

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The injuries are caused by the sharp edges of modern skies or snowboards and require urgent microsurgical intervention.

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Our 20 years study shows that this injury type primarily affects recreational athletes and guest skiers.

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Current equipment, e.g. ski trousers do not protect the affected region on the lateral side of the knee.

Studying Force Patterns in an Alpine Ski Boot and Their Relation to Riding Styles and Falling Mechanisms

In skiing, performance and safety can depend on small details. Consequently, the measurement of forces within the ski boots, which represent the essential form-fitting and force transmitting interface during skiing, will lead to enhanced performance and more importantly safety. This study presents a methodology to measure force patterns (continuous data acquisition) under laboratory as well as realistic slope conditions. The force measurements will be analyzed to gain insights of the skiing style, skiing technique, specific falling mechanisms (i.e., boot induced anterior drawer, phantom foot, hyperextension of the knee joint, and valgus-external rotation). Furthermore, the locations of force sensors in a overlap designed ski boot are discussed in terms of practicability and applicability. These insights are of particular interest to derive release conditions for predictive binding systems and furthermore provide data to improve the style of skiing (e.g., turn release action or center of gravity behavior). For that purpose, a ski boot was instrumented with seven force (piezoresistive) sensors while the basic structure of the boot and the binding remained unchanged. Three sensors were placed on the insole to measure ground reaction forces as well as the contact forces between the skier's foot and the boot. The other four sensors were positioned at spoiler/shaft and toecap (front sole) regions of the ski boot. The locations of the force sensors within the ski-boot are defined with regard to the main body movement while skiing (body-related planes). In addition, a commercially available ski and body mount measuring system were utilized to correlate speed, inclination and body position with the force patterns occurring during skiing on the slope as well as simulating specific body positions on an inclined ramp under laboratory conditions. The measured force revealed that the toecap (upper) sensors provide insufficient even non-conclusive data to deduce significant patterns. However, the insole sensors (heel and front sole area) as well as the spoiler/shaft (back) sensors are more reliable and show characteristic patterns indicating forward or backward lean. These results will have an important impact to the development of predictiveelectro-mechanical bindings to prevent knee-related injuries, which, from a statistical point of view, concerns largely women and young athletes.

Wide Skis As a Potential Knee Injury Risk Factor in Alpine Skiing

Alpine skis with wider waist widths have recently become more popular. With such skis, the contact point of the ground reaction force during ski turns is displaced more medially from beneath the sole of the outer ski, which may present an increased risk of injury. The aim of this study was to investigate knee joint kinetics, kinematics, and lower limb muscle activation as a function of changes of the ski waist width in a laboratory setting. A custom skiing simulator was constructed to enable simulation of different ski waist widths in a quasi-static ski turn position. An optical system was used for capturing knee joint kinematics of the outer leg, whereas a force plate was used to determine the ground reaction force vector. The combination of both systems enabled values for external torques acting on the knee joint to be calculated, whereas electromyographic measurements enabled an analysis of knee flexor muscle activation. With respect to the outer ski, the knee joint external torques were independent of ski waist width, whereas knee joint external rotation and biceps femoris activation increased significantly with the increase of the ski waist width. Skier muscle and kinematics adaptation most probably took place to diminish the external knee joint torque changes when the waist width of the ski was increased. The laboratory results suggest that using skis with large waist widths on hard, frozen surfaces may change the load of knee joint surfaces. However, future research is needed to clarify if this may result in the increased risk of knee injury.

The Influence of Ski Waist-Width and Fatigue on Knee-Joint Stability and Skier’s Balance

Alpine skiing is a complex sport that demands a high level of motor control and balance. In general, skiers are prone to deterioration in the state of fatigue due to using inappropriate equipment. As a consequence, the risk of injury might increase. This study aimed to examine the influence of fatigue and ski waist-width on knee-joint stability and skier’s balance. A laboratory skiing simulation in a quasistatic ski-turning position was conducted where the lower-limb kinematics was recorded using an optical system, and the balance-determining parameters were captured using a force plate. It was demonstrated that the knee-joint kinematics and skier’s balance were hampered in the state of fatigue, as well as when using skis with a large waist-width. The results of the study suggest avoiding the fatigue state and the use of skis having a large waist-width while skiing on hard surfaces to decrease the risk of injury.

How to Prevent Injuries in Alpine Ski Racing: What Do We Know and Where Do We Go from Here?

Alpine ski racing is known to be a sport with a high risk of injury and a high proportion of time-loss injuries. In recent years, substantial research efforts with regard to injury epidemiology, injury etiology, potential prevention measures, and measures’ evaluation have been undertaken. Therefore, the aims of this review of the literature were (i) to provide a comprehensive overview of what is known about the aforementioned four steps of injury prevention research in the context of alpine ski racing; and (ii) to derive potential perspectives for future research. In total, 38 injury risk factors were previously reported in literature; however, a direct relation to injury risk was proven for only five factors: insufficient core strength/core strength imbalance, sex (depending on type of injury), high skill level, unfavorable genetic predisposition, and the combination of highly shaped, short and wide skis. Moreover, only one prevention measure (i.e. the combination of less-shaped and longer skis with reduced profile width) has demonstrated a positive impact on injury risk. Thus, current knowledge deficits are mainly related to verifying the evidence of widely discussed injury risk factors and assessing the effectiveness of reasonable prevention ideas. Nevertheless, the existing knowledge should be proactively communicated and systematically implemented by sport federations and sport practitioners.

Sports-specific differences in postsurgical infections after arthroscopically assisted anterior cruciate ligament reconstruction

PURPOSE

Post-operative infection after arthroscopically assisted anterior cruciate ligament (ACL) reconstruction is a rare but severe complication, particularly for young and active patients. It is unclear whether the prevalence of knee infection is correlated with the type of sports or the level of performance.

METHODS

From 2008 to 2012, the internal single-centre ACL registry of the FIFA Medical Centre of Excellence Regensburg was retrospectively screened for sex, age, time between isolated primary ACL rupture and surgery, surgical technique, rate of infection after ACL reconstruction and the type of sports practised.

RESULTS

In total, 4801 ACL reconstructions had been conducted over 5 years, 4579 in amateur and 221 in professional athletes. After application of the exclusion criteria, 1809 athletes with ACL reconstruction were analysed regarding postsurgical infection and the type of sports practised. Professionals and amateurs did not significantly differ with regard to infection rates (n.s.) but in the timing of ACL repair (p < 0.001). Eleven of 1130 football players had developed postsurgical infection after ACL reconstruction (1.0%) in contrast to 557 skiers and snowboarders without infection (p = 0.02). The timing of ACL repair did not differ between the different types of sports (n.s.). Staphylococcus aureus and epidermidis were the predominant detected bacteria. All patients were hospitalised and successfully treated with arthroscopic lavage and antibiotic medication.

CONCLUSION

ACL infections showed sports-related differences. Athletes practising summer outdoor sports such as football had a significantly higher risk of infection after ACL reconstruction than winter sports athletes. No difference was found between professional and amateur athletes. Relevant prevention strategies for postsurgical ACL infections should consider influencing patient factors such as the type of sports activity and attendant circumstances.

LEVEL OF EVIDENCE

III.

[Severe blunt thoracic trauma caused by ski collision]

An approximately 25-year-old skier collided in a ski-run intersection. At high speed, he first hit another skier and then smashed into a snow cannon. He died from his injuries a short time later in hospital. A whole-body CT scan was conducted under resuscitation conditions, which was followed by an autopsy. The investigation revealed a severe blunt thoracic trauma as cause of death. The detailed analysis was the result of the combination of the two methods of investigation, CT scan and autopsy. The methods complemented each other effectively and allowed for a detailed presentation of the injury pattern. In conjunction with the additional analytical accident report, this combination of CT scan and autopsy contributes towards a reconstruction of accidents and the development of prevention measures and related protective systems.