Video analysis of Achilles tendon ruptures in professional male football (soccer) reveals underlying injury patterns and provides strategies for injury prevention

PURPOSE

In professional football (soccer), Achilles tendon ruptures are severe injuries. Video analysis promotes a better understanding of the underlying situational and biomechanical patterns, and provides a roadmap for future research to improve the management and prevention of Achilles tendon ruptures. The purpose of this study was to identify injury patterns contributing to acute Achilles tendon ruptures in professional male football players.

METHODS

Professional male football players with an acute Achilles tendon rupture were identified using an online database. For every in-competition injury, the corresponding football match was detected. Video footage of the injury was accessed using Wyscout.com or publicly available video databases. Situational patterns and injury biomechanics of the injury frame were independently analysed by two reviewers using a standardised checklist and a motion analysis software. Finally, consensus was reached to describe the main injury patterns of Achilles tendon ruptures in professional male football players.

RESULTS

The search identified video footage of 80 Achilles tendon ruptures in 78 players. Most injuries (94%) occurred through indirect or non-contact mechanisms. The kinematic analysis revealed characteristic joint positions at the time of injury consisting of hip extension, knee extension, ankle dorsiflexion, foot abduction, and foot pronation in most cases. The underlying direction of movement was from flexion to extension (knee) and from plantarflexion to dorsiflexion (ankle). Player actions identified as main injury patterns were stepping back (26%), landing (20%), running/sprinting (18%), jumping (13%), and starting (10%).

CONCLUSION

Most Achilles tendon ruptures in professional male football players are closed-chain indirect or non-contact injuries. Sudden loading to the plantarflexor musculotendinous unit remains to be the main component for most cases. By achieving a better understanding of underlying injury mechanisms, this study provides new strategies for the prevention of Achilles tendon ruptures.

LEVEL OF EVIDENCE

Level IV.

Return to Play and Pattern of Injury After ACL Rupture in a Consecutive Series of Elite UEFA Soccer Players

Background

Anterior cruciate ligament rupture represents a career-threatening injury for professional soccer players.

Purpose

To analyze the pattern of injury, return to play (RTP), and performance of a consecutive series of elite professional soccer players after anterior cruciate ligament reconstruction (ACLR).

Study Design

Case series; Level of evidence, 4.

Methods

We evaluated the medical records of 40 consecutive elite soccer players who underwent ACLR by a single surgeon between September 2018 and May 2022. Patient age, height, weight, body mass index, position, injury history, affected side, RTP time, minutes played per season (MPS), and MPS as a percentage of playable minutes before and after ACLR were retrieved from medical records and from publicly available media-based platforms.

Results

Included were 27 male patients (mean ± SD age at surgery, 23.2 ± 4.3 years; range, 18-34 years). The injury occurred during matches in 24 players (88.9%), with a noncontact mechanism in 22 (91.7%). Meniscal pathology was found in 21 patients (77.8%). Lateral meniscectomy and meniscal repair were performed in 2 (7.4%) and 14 (51.9%) patients, respectively, and medial meniscectomy and meniscal repair were performed in 3 (11.1%) and 13 (48.1%) patients, respectively. A total of 17 players (63.0%) underwent ACLR with bone-patellar tendon-bone autograft and 10 (37.0%) with soft tissue quadriceps tendon. Lateral extra-articular tenodesis was added in 5 patients (18.5%). The overall RTP rate was 92.6% (25 of 27). Two athletes moved to a lower league after surgery. The mean MPS% during the last preinjury season was 56.69% ± 21.71%; this decreased significantly to 29.18% ± 20.6% (P < .001) in the first postoperative season and then increased to 57.76% ± 22.89% and 55.89% ± 25.8% in the second and third postoperative seasons. Two (7.4%) reruptures and 2 (7.4%) failed meniscal repairs were reported.

Conclusion

ACLR in elite UEFA soccer players was associated with a 92.6% rate of RTP and 7.4% rate of reinjury within 6 months after primary surgery. Moreover, 7.4% of soccer players moved to a lower league during the first season after surgery. Age, graft selection, concomitant treatments, and lateral extra-articular tenodesis were not significantly associated with prolonged RTP.

Risk factors for hamstring muscle injury in male elite football: medical expert experience and conclusions from 15 European Champions League clubs

Objectives

To describe the perceived importance of suggested hamstring injury risk factors according to chief medical officers (CMOs) of European male professional football clubs. A secondary objective was to compare if these perceptions differed between teams with a lower-than-average hamstring injury burden and teams with a higher than average hamstring injury burden.

Methods

First, CMOs of 15 European professional male football clubs were asked to suggest risk factors for hamstring injury in their club. The perceived importance of the suggested risk factors was then rated by all participants on a 5-graded Likert scale. Participating teams were divided in two groups depending on their hamstring injury burden during the 2019/2020 and 2020/2021 seasons. The LOW group consisted of seven teams that had a lower than average hamstring injury burden. The HIGH group consisted of eight teams that had a higher-than-average hamstring injury burden.

Results

Twenty-one risk factors were suggested. The majority were extrinsic in nature, associated with coaching staff, team or club rather than players themselves. 'Lack of communication between medical staff and coaching staff' had the highest average importance (weighted average=3.7) followed by 'Lack of regular exposure to high-speed football during training sessions' (weighted average=3.6). The HIGH group perceived the player factors fatigue and wellness as more important than the LOW group.

Conclusion

According to CMOs recruited in this study, most risk factors for hamstring injuries are extrinsic and associated with the club and coaching staff, and not the players themselves.

Nonoperative treatment of muscle injuries - recommendations from the GOTS expert meeting

BACKGROUND

Muscle injuries are some of the most common injuries in sports; they have a high recurrence rate and can result in the loss of ability to participate in training or competition. In clinical practice, a wide variety of treatment strategies are commonly applied. However, a limited amount of evidence-based data exists, and most therapeutic approaches are solely based on "best practice". Thus, there is a need for consensus to provide strategies and recommendations for the treatment of muscle injuries.

METHODS

The 2016 GOTS Expert Meeting, initiated by the German-Austrian-Swiss Society for Orthopaedic Traumatologic Sports Medicine (GOTS), focused on the topic of muscle and tendon injuries and was held in Spreewald/Berlin, Germany. The committee was composed of twenty-two medical specialists. Nine of them were delegated to a subcommittee focusing on the nonoperative treatment of muscle injuries. The recommendations and statements that were developed were reviewed by the entire consensus committee and voted on by the members.

RESULTS

The committee reached a consensus on the utility and effectiveness of the management of muscle injuries.

MAIN RESULTS

the "PRICE" principle to target the first inflammatory response is one of the most relevant steps in the treatment of muscle injuries. Haematoma aspiration may be considered in the early stages after injury. There is presently no clear evidence that intramuscular injections are of use in the treatment of muscle injuries. The ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) should be regarded critically because there is currently no hard evidence to support their use, although they are appropriate in exceptional cases.

CONCLUSIONS

The present work provides a structured overview of the various nonoperative treatment strategies of muscle injuries and evaluates their effectiveness with respect to the existing scientific evidence and clinical expertise in the context of basic science on the healing process of muscle injuries. The committee agreed that there is a compelling need for further studies, including high-quality randomized investigations to completely evaluate the effectiveness of the existing therapeutic approaches. The given recommendations may be updated and adjusted as further evidence will be generated.

[Impact of Vitamin D in Sports: Does Vitamin D Insufficiency Compromise Athletic Performance?]

Introduction Vitamin D is essential for calcium homeostasis and regulates the expression of over 900 genes. It thereby influences musculoskeletal health and function. Additionally, multiple other effects were observed through the detection of vitamin D receptors (VDR) in numerous tissues of the human body. Material and Methods We reviewed the literature regarding evidence of the impact of vitamin D on musculoskeletal health and peak athletic performance. Results and Discussion It is well known that there is a high prevalence of vitamin D deficiency in the average European population. This article confirmed the same for athletes in different disciplines. Therefore, vitamin D deficiency and its effects are relevant for competitive sports. The surprisingly high prevalence of inadequate vitamin D levels depends on the geographic location, the time of day and year, local climate conditions, and sports disciplines (indoor vs. outdoor). Based on the analysed literature, we found several correlations between 25-OH-D3 serum levels and different aspects of competitive sports. A serum level ≥ 30 ng/ml provides sufficient mineralisation of non-mineralised bone matrix and is therefore crucial for skeletal health. Furthermore, this concentration was positively correlated with an accelerated regeneration of muscular force. Levels above 40 ng/ml provided a protective effect on the development of stress fractures. Researchers suspect that levels above 50 ng/ml are required for athletes to achieve maximal physical performance. While there is an ongoing discussion amongst researchers regarding beneficial effects of such high levels, it is well known that blood levels lower than 30 ng/ml lead to mineralisation defects in bone (rickets, osteomalacia) and muscular function (reversible myopathy). Conclusion This review suggests that athletes should have an evaluation of vitamin D-dependent calcium homeostasis based on laboratory tests of 25-OH-D3, calcium, creatinine, and parathyroid hormone. In case of vitamin D insufficiency, normal blood levels of ≥ 30 ng/ml may be restored by optimising the athlete's lifestyle and, if appropriate, oral substitution of cholecalciferol. This concentration is associated with a protective effect and enhancement of physical performance. Consequently, it is a requirement for restoring and maintaining musculoskeletal health and athletic performance.

Nonoperative treatment and return to play after complete proximal adductor avulsion in high-performance athletes

PURPOSE

To assess the outcome of nonoperative treatment after complete avulsion of the proximal adductor longus tendon in high-performance athletes.

METHODS

Six consecutive athletes were included. Treatment was conservative following a strict rehabilitation plan. Following parameters were analysed: basic data, mechanism of injury, classification, tendon retraction, size of defect in MRI and return to play (RTP).

RESULTS

Mean age at injury was 28 ± 5 (range 20-32) years. Overstretch (83 %) and kicking (50 %) were the most frequent injury mechanisms, and the dominant leg was involved in 83 %. Average retraction of the avulsed tendon amounted 21 ± 5 mm. Follow-up MRIs demonstrated a gradual reattachment of the tendon in all cases. All athletes returned to full sportive activity on preinjury level within 88.7 ± 12.8 (range 75-110) days with no functional deficiencies. Manual muscle strength was equal to the contralateral side.

CONCLUSION

Nonoperative treatment with a healing phase and a strict rehabilitation plan results in a functional, efficient reattachment of the tendon and allows unrestricted RTP. Since these injuries are rare, present study may help sports physicians when dealing with this type of injuries in professional athletes. Return to sports can be expected at approximately 13 weeks after injury, but can take even longer.

LEVEL OF EVIDENCE

Case series, Level IV.

Treatment of muscle injuries in football

Muscle injuries are frequent and represent one of the most substantial medical problems in professional football. They can have both traumatic and overuse causes with direct practical consequence due to differences in terms of the post-primary care regimen and prognosis. An accurate diagnosis is the first step towards a specific treatment and usually allows to predict return to play (RTP). Current treatment principles have no firm scientific basis; they are practiced largely as empirical medicine due to a lack of prospective randomised studies. Immediate treatment usually follows the PRICE-principle (protection, rest, ice, compression, elevation). Depending on the type of the muscle injury, specific physical and physiotherapeutical procedures as well as rehabilitative exercises and gradual training therapy are used to recondition the injured structure, to restore coordination and proprioception, and to normalise movement patterns. Injection therapy with various substances is frequently used, with positive results empirically, but evidence in form of prospective randomised studies is lacking. A precise rehabilitation plan should be developed for every muscle injury, including recommendations for sport-specific training with increasing intensity. Since there are no guidelines regarding safe RTP, regular follow-up examinations on the current muscle status are crucial to evaluate the progress made in terms of healing and to determine when the injured muscle can be exposed to the next step of load. This narrative review describes the various factors that a medical team should consider during assessment, treatment and rehabilitation of a muscle injury with particular focus on professional football.

Intra-articular osteoid osteoma as a differential diagnosis of diffuse mono-articular joint pain

Background

The aim of this retrospective study was to investigate the frequency of intra-articular osteoid osteoma (iaOO) in a large study cohort and to demonstrate its clinical relevance as an important differential diagnosis of non-specific mono-articular joint pain.

Methods

We searched the registry for bone tumours of the University Medical Centre Hamburg-Eppendorf for osteoid osteomas in the last 42 years. Herein, we present three selected iaOO which were detected in the three major weight-bearing joints. Computed tomography (CT) or magnetic resonance imaging (MRI) scans were performed for initial diagnosis.

Results

Out of a total of 367 osteoid osteomas, 19 (5.2 %) tumours were localized intra-articularly. In all three presented tumours, a history of severe mono-articular pain was reported; however, the mean time to correct diagnosis was delayed to 20.7 months. Clearly, the nidus seen in CT and MRI images in combination with inconsistent salicylate-responsive nocturnal pain led to the diagnosis of iaOO.

Conclusions

Rarely, osteoid osteoma can occur in an intra-articular location. In cases of diffuse mono-articular pain, iaOO should be considered both in large and smaller joints to avoid delays in diagnosis and therapy of this benign bone tumour.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1313-3) contains supplementary material, which is available to authorized users.

Suture anchor repair of proximal rectus femoris avulsions in elite football players

PURPOSE

To report the results of suture anchor repair of proximal rectus femoris avulsions in elite football players.

METHODS

Four professional football players (first-team regulars of European first division football clubs) underwent suture anchor repair of complete proximal rectus femoris avulsions with significant tendon retraction. The following parameters were analysed: demographic data, mechanism of injury, type of injury, classification according to the Munich consensus statement, time between injury and surgery, time between surgery and full participation in training and availability for match and/or competition selection (return to play/RTP), and time between surgery and the comeback to the first official league match (return to competition/RTC). Radiographic evaluation was performed by magnetic resonance imaging (MRI) obtained pre-operatively and at 6 and 12 weeks post-operatively. All players were followed for at least 24 months after return to play to exclude recurrence.

RESULTS

Mean age at surgery was 30 ± 2 years. All injuries occurred while kicking a ball, with the dominant leg affected in all patients. The injury was considered acute in three cases and chronic in one case. According to the Munich classification, all injures were type 4. Mean time to surgery was 60 ± 88 days (range, 8-191), mean time to RTP was 111 ± 15 days (range, 100-134), and mean time to RTC was 140 ± 23 days (range, 114-166). Follow-up MRIs demonstrated anatomically reinserted tendons with decreasing signal intensity over time in all cases. After a mean follow-up of 35 ± 6 months, all players were still competing at the same level as before the injury without re-injury.

CONCLUSION

Suture anchor repair of proximal rectus femoris avulsions allows unrestricted return to play in professional elite football players. Return to play can be expected at approximately 16 weeks post-operatively.

Intravenous bisphosphonates and vitamin D in the treatment of bone marrow oedema in professional athletes

INTRODUCTION

The goal of this retrospective study was to evaluate the safety and efficacy of ibandronate for bone marrow oedema (BMO) syndrome and stress fracture cases, and to demonstrate an additional field of therapeutic importance-the high-performance athlete.

PATIENTS AND METHODS

This retrospective study included twenty-five high-performance athletes. Sixty per cent of the athletes were European soccer players and 40.0% other high-class international athletes (3 women and 22 men with an average age of 25.0±4.2), with BMO of the lower trunk or extremity diagnosed by magnetic resonance imaging (MRI). The treatment regimen consisted of high-dose vitamin D supplementation and intravenous ibandronate therapy.

RESULTS

The time between the onset of pain and proper diagnosis of BMO was 106.3±104.1 days. Excellent pain reduction (pain at rest and under strain) and improved mobility was reported within the first two weeks after the first ibandronate administration by sixteen patients (64%). The time from first treatment until return to competition (RTC) was on average 102.6±65.2 days in total. If the time from onset of pain until diagnosis was within 40 days, the RTC was significantly reduced (p≤0.05) to almost 50% (63.8±48.1 days) when compared to the athletes with later diagnosis (124.4±63.2 days).

CONCLUSIONS

The here-applied therapy regimen of intravenous BPs application and vitamin D supplementation in BMO syndrome has a beneficial effect for high-performance athletes. An early diagnosis and rapid treatment start can reduce the RTC significantly. An optimal bone metabolism with sufficient daily calcium and vitamin D intake is crucial and should not only be strived for the professional but also for the recreational athlete.

Terminology and classification of muscle injuries in sport: the Munich consensus statement

Objective

To provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies.

Methods

Thirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to complete a questionnaire on muscle injuries to evaluate the currently used terminology of athletic muscle injury. In addition, a consensus meeting of international sports medicine experts was established to develop practical and scientific definitions of muscle injuries as well as a new and comprehensive classification system.

Results

The response rate of the survey was 63%. The responses confirmed the marked variability in the use of the terminology relating to muscle injury, with the most obvious inconsistencies for the term strain. In the consensus meeting, practical and systematic terms were defined and established. In addition, a new comprehensive classification system was developed, which differentiates between four types: functional muscle disorders (type 1: overexertion-related and type 2: neuromuscular muscle disorders) describing disorders without macroscopic evidence of fibre tear and structural muscle injuries (type 3: partial tears and type 4: (sub)total tears/tendinous avulsions) with macroscopic evidence of fibre tear, that is, structural damage. Subclassifications are presented for each type.

Conclusions

A consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. This will help to improve clarity of communication for diagnostic and therapeutic purposes and can serve as the basis for future comparative studies to address the continued lack of systematic information on muscle injuries in the literature.

What are the new things

Consensus definitions of the terminology which is used in the field of muscle injuries as well as a new comprehensive classification system which clearly defines types of athletic muscle injuries.

Level of evidence

Expert opinion, Level V.

Identification of molecular markers for articular cartilage

OBJECTIVE

The aim of the current study was to identify molecular markers for articular cartilage (AC) that can be used as tools for the quality control of tissue engineered (TE) cartilage.

DESIGN

A genome-wide expression analysis was performed using RNA isolated from articular and growth plate (GP) cartilage, both extracted from the knee joints of 6 weeks old minipigs. After confirming the specific expression for selected genes by RT-PCR, these were used as molecular markers for the quality control of TE cartilage.

RESULTS

Albeit several known chondrocyte markers were expressed to a similar extent in articular and GP cartilage, our genome-wide expression analysis led us to identify genes being selectively expressed in either GP or articular chondrocytes. These findings led us to perform a RT-PCR expression analysis for the corresponding genes to demonstrate the absence of GP-specific markers in TE cartilage, while common or AC markers were expressed.

CONCLUSIONS

Taken together, these results provide important novel insights into chondrocyte biology in general and AC in particular. In addition, it is reasonable to speculate, that some of the identified genes play distinct roles in the regulation of articular chondrocyte differentiation and/or function, thereby raising the possibility that they may serve as targets for non-operative therapies of osteoarthritis (OA).

The influence of the stable expression of BMP2 in fibrin clots on the remodelling and repair of osteochondral defects

Growth factors like BMP2 have been tested for osteochondral repair, but transfer methods used until now were insufficient. Therefore, the aim of this study was to analyse if stable BMP2 expression after retroviral vector (Bullet) transduction is able to regenerate osteochondral defects in rabbits. Fibrin clots colonized by control or BMP2-transduced chondrocytes were generated for in vitro experiments and implantation into standardized corresponding osteochondral defects (n=32) in the rabbit trochlea. After 4 and 12 weeks repair tissue was analysed by histology (HE, alcian-blue, toluidine-blue), immunohistochemistry (Col1, Col2, aggrecan, aggrecan-link protein), ELISA (BMP2), and quantitative RT-PCR (BMP2, Col1, Col2, Col10, Cbfa1, Sox9). In vitro clots were also analysed by BMP2-ELISA, histology (alcian-blue), quantitative RT-PCR and in addition by electron microscopy. BMP2 increased Col2 expression, proteoglycan production and cell size in vitro. BMP2 transduction by Bullet was efficient and gene expression was stable in vivo over at least 12 weeks. Proteoglycan content and ICRS-score of repair tissue were improved by BMP2 after 4 and 12 weeks and Col2 expression after 4 weeks compared to controls. However, in spite of stable BMP2 expression, a complete repair of osteochondral defects could not be demonstrated. Therefore, BMP2 is not suitable to regenerate osteochondral lesions completely.

The fate of osteochondral grafts after autologous osteochondral transplantation: a one-year follow-up study in a minipig model

INTRODUCTION

Because articular cartilage shows little intrinsic capacity of spontaneous regeneration, a variety of treatment options are currently at use to repair cartilage damage. One of these is the autologous osteochondral transplantation (AOT). The aim of the present work was to study the histological changes during the progress of 1 year after AOT in the knee joint.

MATERIALS AND METHODS

Twelve Minipigs underwent an AOT on the medial femoral condyles of both knees using cooled diamond studded trephines with a diameter of the grafts of 4.6 mm. Three animals were sacrificed at each 2, 8, 26 and 52 weeks after the operation. The condyles were analyzed histologically and immunohistologically for collagen types I and II.

RESULTS

A successful bony incorporation was observed in all specimens. The transplant demonstrated an increasingly stable integration of the chondral matrix into the cartilage of the surrounding femoral condyle. At 52 weeks after the operations 5 of 6 condyles showed a chondral integration at least at one side of the graft. Immunohistologically all specimens showed physiological staining characteristics up to 52 weeks after operation. The quality of the chondral part of the graft showed a wide range of variations, ranging from vital tissue resembling native cartilage after 52 weeks, to severe degenerative signs beginning 2 weeks after operation and ending at 52 weeks with deep fissures fragmenting the cartilage and the complete loss of vital cells.

CONCLUSION

The press-fit technique allows a stable bony incorporation. A chondral integration of the graft seems to occur, provided that a close contact between the interfaces can be achieved. Present results demonstrate a vital cartilagenous transplant for up to 52 weeks. However, some specimens showed in part severe degenerative signs. A possible explanation is an insufficient cooling of the trephines in relation to the small diameter of the grafts used in the minipig model. The collagen network seems not to be affected for up to 52 weeks.

Long term results after implantation of tissue engineered cartilage for the treatment of osteochondral lesions in a minipig model

In present study we determined the long term in vivo integration and histological modeling of an in vitro engineered cartilage construct. Tissue engineered autologous cartilagenous tissue was cultured on calcium phosphate cylinders and implanted into osteochondral defects into the femoral condyles in minipigs. Radiological follow-up was performed at 2, 8, 26 and 52 weeks, condyles were harvested 26 and 52 weeks post-implantation. Thickness of cultivated tissue (1.10 +/- 0.55 mm) was comparable to in situ cartilage and cells produced in vitro cartilage specific proteins. In vivo, 26 and 52 weeks post-implantation defects were resurfaced with hyaline-like tissue, the implants were well integrated with no gap at the interface between the engineered neocartilage and the adjacent articular cartilage. Synthesis of type II collagen was detected 26 and 52 weeks after implantation. The modified ICRS score increased from 26 to 52 weeks. Histomorphometric evaluation revealed a decrease in cellularity in tissue engineered cartilage from 2.2-fold of native cartilage after 26 weeks to 1.5-fold after 52 weeks. In conclusion, these findings demonstrate the integration and maturation of tissue engineered cartilage pellets attached on a bone substitute carrier implanted in osteochondral defects over a long time.

In vitro analysis of an allogenic scaffold for tissue-engineered meniscus replacement

Scaffolds play a key role in the field of tissue engineering. Particularly for meniscus replacement, optimal scaffold properties are critical. The aim of our study was to develop a novel scaffold for replacement of meniscal tissue by means of tissue engineering. Emphasis was put on biomechanical properties comparable to native meniscus, nonimmunogenecity, and the possibility of seeding cells into and cultivating them within the scaffold (nontoxicity). For this purpose, native ovine menisci were treated in vitro in a self-developed enzymatic process. Complete cell removal was achieved and shown both histologically and electron microscopically (n = 15). Immunohistochemical reaction (MHC 1/MHC 2) was positive for native ovine meniscus and negative for the scaffold. Compared to native meniscus (25.8 N/mm) stiffness of the scaffold was significantly increased (30.2 N/mm, p < 0.05, n = 10). We determined the compression (%) of the native meniscus and the scaffold under a load of 7 N. The compression was 23% for native meniscus and 29% for the scaffold (p < 0.05, n = 10). Residual force of the scaffold was significantly lower (5.2 N vs. 4.9 N, p < 0.05, n = 10). Autologous fibrochondrocytes were needle injected and successfully cultivated within the scaffolds over a period of 4 weeks (n = 10). To our knowledge, this study is the first to remove cells and immunogenetic proteins (MHC 1/MHC 2) completely out of native meniscus and preserve important biomechanical properties. Also, injected cells could be successfully cultivated within the scaffold. Further in vitro and in vivo animal studies are necessary to establish optimal cell sources, sterilization, and seeding techniques. Cell differentiation, matrix production, in vivo remodeling of the construct, and possible immunological reactions after implantation are subject of further studies.

Mechanical evaluation of different techniques for Achilles tendon repair

INTRODUCTION

One aim of the surgical treatment of acute Achilles tendon ruptures is to obtain a maximum primary stability of the sutured tendon. Therefore, we investigated the primary stability of sutured human Achilles tendons depending on different applied techniques.

METHODS

The strength of 60 repaired cadaveric human Achilles tendons was tested depending on either the suture technique (Bunnell or Kessler), the suture material (PDS-thread or PDS-cord) or an additional plantaris tendon augmentation (PDS-thread with or without augmentation). Following anatomic reconstruction the repaired specimens were loaded to failure.

RESULTS

The use of Bunnell's technique resulted in a stronger primary suture stability compared to Kessler's technique. Sutures carried out with a PDS-thread were of lower strength than those accomplished with a PDS-cord (Bunnell: thread 139 N +/- 29.8; cord 291 N +/- 55.2/Kessler: thread 137 N +/- 37.3; cord 180 N +/- 41.1). Sutures performed according to Bunnell's technique with a PDS-thread and an additional autologous plantaris tendon augmentation reached the highest primary stability (326 N +/- 124.9).

CONCLUSIONS

The findings identify the Achilles tendon suture with a PDS-cord according to Bunnell's technique as a mechanically strong method. A plantaris tendon augmentation in addition to a PDS-thread can even add more stability to the Achilles tendon suture.

Osteochondral transplantation to treat osteochondral lesions in the elbow

BACKGROUND

Effective treatment of osteochondral lesions in the elbow remains challenging. Arthroscopic débridement and microfracture or retrograde drilling techniques are often insufficient and provide only temporary symptomatic relief. The purpose of this study was to evaluate the treatment of these lesions with osteochondral autografts.

METHODS

From 1999 to 2002, seven patients with osteochondral lesions of the capitellum humeri (five patients), trochlea (one patient), or radial head (one patient) were treated with cylindrical osteochondral grafts, which were harvested from the non-weight-bearing area of the proximal aspect of the lateral femoral condyle. The patients (three female and four male patients with an average age of seventeen years) were evaluated preoperatively and postoperatively, with an average follow-up of fifty-nine months. The Broberg and Morrey score was chosen for functional evaluation of the elbow (with regard to motion, pain, strength, activities of daily living, and stability), and the American Shoulder and Elbow Surgeons score was used for the analysis of pain. All patients had imaging studies done preoperatively to evaluate the defect and postoperatively to assess the ingrowth and viability of the graft. The ipsilateral knee was examined for donor-site morbidity.

RESULTS

The Broberg and Morrey score improved from a mean (and standard deviation) of 76.3 +/- 13.2 preoperatively to 97.6 +/- 2.7 postoperatively, and pain scores were significantly reduced (p < 0.05). The mean elbow extension lag of 4.7 degrees +/- 5.8 degrees was reduced to 0 degrees postoperatively. Compared with the contralateral side, there was a mean preoperative flexion lag of 12.9 degrees +/- 13.8 degrees . At the time of the final follow-up, flexion was free and was equal bilaterally in all patients. None of the plain radiographs made at the time of follow-up showed any degenerative changes or signs of osteoarthritis. The postoperative magnetic resonance imaging scans showed graft viability and a congruent chondral surface in all seven patients. No donor-site morbidity was noted at one year postoperatively.

CONCLUSIONS

The osteochondral autograft procedure described in the present study provides the opportunity to retain viable hyaline cartilage for the repair of osteochondral lesions in the elbow while restoring joint congruity and function and perhaps reducing the risk of osteoarthritis. These medium-term results suggest that the risks of a two-joint procedure are modest and justifiable. In addition, the described technique provides an option for revision surgery after the failure of other surgical procedures.

Arthroscopical Findings after Antegrade Nailing of a Proximal Humeral Fracture : Case Report and Review of the Literature

Proximal humeral fractures represent up to five percent of all fractures in adults, commonly found in elderly patients. The final functional results after different operative procedures are among other factors dependent on whether or not a rotator cuff lesion is pre-existent, prior to the fracture, and how its surgical therapy is carried out. However, to what extent prior rotator cuff tears in this special patient group contribute to the functional outcome remains widely unclear. In our institution antegrade intramedullary nailing is the treatment of choice for proximal humeral fractures. One critical point of this technique is the unavoidable split of the rotator cuff on the approach to the proximal humerus and the insertion of the nail through the incised cuff. We report on a case of an impingement after antegrade intramedullary nailing of a proximal humeral fracture. Diagnostic glenohumeral arthroscopy revealed neither a residual lesion of the former rotator cuff incision nor a chondral lesion at the former insertion site of the nail. In the same session subacromial decompression and a nettoyage of adhesions were performed. We assume that splitting the rotator cuff for the insertion of an antegrade nail in a proximal humeral fracture is less relevant than previously assumed and described.

In vivo analysis of retroviral gene transfer to chondrocytes within collagen scaffolds for the treatment of osteochondral defects

To examine a retroviral gene transfer to chondrocytes in vitro and in vivo in tissue-engineered cell-collagen constructs articular chondrocytes from rabbits and humans were isolated and transduced with VSV.G pseudotyped murine leukemia virus-derived retroviral vectors. Viral supernatants were generated by transient transfection of 293T cells using the pBullet retroviral vector carrying the nlslacZ gene, a Moloney murine leukemia virus gag/pol plasmid and a VSV.G coding plasmid. Transduction efficiency was analyzed by fluorescence-activated-cell-sorter analysis and transduced autologous chondrocytes from rabbits were seeded on collagen-scaffolds and implanted into osteochondral defects in the patellar groove of the rabbit's femur (n=10). LacZ-expression was analyzed by X-gal staining on total knee explants and histological sections. Retroviral transduction efficiency exceeded 92.3% (SEM+/-3.5%) in rabbit articular chondrocytes, 74.7% (SEM+/-1.8%) in human articular chondrocytes and 52.7% (SEM+/-5.8%) in osteoarthritic human chondrocytes. Reporter gene expression remained high after 15 weeks in 75.7% (SEM+/-8.2%) of transduced rabbit articular chondrocytes. In vivo, intraarticular beta-galactosidase activity could be determined in the majority of implanted chondrocytes in the osteochondral defects after 4 weeks.

Antegrade nailing of humeral head fractures with captured interlocking screws

OBJECTIVES/DESIGN

To assess the functional outcome after treatment of proximal humeral fractures with a new antegrade nail that provides angular and sliding stability. INTERVENTION/PATIENTS: Ninety-seven patients were treated during a 4-year period between April 2000 and March 2004. All patients were followed for 6 months, 51 patients (53%) for 12 months, and 31 patients (32%) for 24 months. This study focuses mainly on the patients with a follow up of 1 year. Their mean age was 68 years (range: 33 to 90); 22% were more than 80 years of age.

MAIN OUTCOME MEASUREMENTS

All fractures were radiologically graded by the Neer and AO/ASIF classifications. Clinical assessment was performed at all follow-up visits using the Constant-Murley and Neer scores, and complications were recorded.

RESULTS

There were 26.8% 2-part, 66% 3-part, and 7.2% 4-part fractures. The relative Constant-Murley score improved significantly (P < 0.001) from 72% at 6 months to 82% at 12 months after operation. No further improvement regarding functional outcome was observed after 24 months. Patients younger than 60 years of age had better results. No significant functional differences were found among 2-, 3- or 4-part fractures. Complications included backing out of the proximal screws (9.8%), secondary dislocation (1.9%), complete osteonecrosis (1.9%), and partial osteonecrosis (5.8%).

CONCLUSION

Treatment with this nail provides sufficient fixation of the fragments to allow early mobilization. The good functional results in the majority of the patients indicate that this nail can be used, even in complex fractures and elderly patients.

Second generation of meniscus transplantation: in-vivo study with tissue engineered meniscus replacement

INTRODUCTION

The options available after meniscus loss offer only limited chances for a long-term success. In the following experimental study, we investigated the effect of meniscus tissue engineering on properties of the collagen meniscus implant (CMI).

METHODS

Autologous fibrochondrocytes, obtained per biopsy from adult Merino sheep (n=25), were released from the matrix, cultured in-vitro and seeded into CMI scaffolds (n=10, group 1). Following a 3-week in-vitro culture, the tissue engineered menisci were used for autologous transplantation. Macroscopical and histological evaluation were performed in comparison with non-seeded CMI controls (n=10, group 2) and with meniscus-resected controls (n=5, group 3) after 3 weeks (each 1 animal group 1 and 2) and 3 months.

RESULTS

The lameness score did not show any difference between the groups. Meniscus tissue was found in seven knee joints (group 1), in five knee joints (group 2) and in two knee joints (group 3). The size of the transplants reduced from 25.9+/-4.5 to 20.1+/-10.8 mm (group 1) and from 25.9+/-1.5 to 14.4+/-12.5 mm (group 2). Histologically, enhanced vascularisation, accelerated scaffold re-modelling, higher content of extra-cellular matrix and lower cell number were noted in the pre-seeded menisci in comparison with non-seeded controls. Dense high-cellular fibrous scar tissue was found in two of five cases in the resection control group.

CONCLUSION

Tissue engineering of meniscus with autologous fibrochondrocytes demonstrates a macroscopic and histological improvement of the transplants. However, further development of the methods, especially of the scaffold and of the cell-seeding procedure must prove the feasibility of this procedure for human applications.

Verletzungen und Fehlbelastungsfolgen im Sport

The benefit of regularly performed physical activity as a fundamental component of a healthy lifestyle is uncontradicted. The number of persons who participate in sports in Germany is approximately more than 40 million people, whereof 27.5 million are organised in sport associations. Every year 1.5-2 million sports injuries occur in Germany, which represent 25-30% of all accidents. The costs for treatment amount to a total of 1.5 billion euros. It is estimated that 80% of all sports injuries could be prevented if training and competition were performed correctly. The patterns and risk of injuries differ between particular sport disciplines and are therefore difficult to estimate. Knowledge of specific injury risks is indispensable for prevention of sports injuries. Furthermore this knowledge facilitates both sports physicians' diagnosis and therapy and guidance of the patient. In this review epidemiological data of sport traumatology are surveyed, patterns of injuries of particular sports are described in detail and prevention strategies are given. In a separate section specifics of sports injuries in children are discussed.

Prospective documentation and analysis of the pre- and early clinical management in severe head injury in southern Bavaria at a population based level

Treatment of patients suffering from severe head injury is so far restricted to general procedures, whereas specific pharmacological agents of neuroprotection including hypothermia have not been found to improve the outcome in clinical trials. Albeit effective, symptomatic measures of the preclinical rescue of patients (i.e. stabilization or reestablishment of the circulatory and respiratory system) or of the early clinical care (e.g. prompt diagnosis and treatment of an intracranial space occupying mass, maintenance of a competent circulatory and respiratory system, and others) by and large constitute the current treatment based on considerable organizational and logistical efforts. These and other components of the head injury treatment are certainly worthwhile of a systematic analysis as to their efficacy or remaining deficiencies, respectively. Deficits could be associated with delays of providing preclinical rescue procedures (e.g. until intubation of the patient or administration of fluid). Delays could also be associated in the hospital with the diagnostic establishment of intracranial lesions requiring prompt neurosurgical intervention. By support of the Federal Ministry of Education and Research and under the auspices of the Forschungsverbund Neurotraumatology, University of Munich, a prospective system analysis was carried out on major aspects of the pre- and early clinical management at a population based level in patients with traumatic brain injury. Documentation of pertinent data was made from August 1998 to July 1999 covering a catchment area of Southern Bavaria (5.6 mio inhabitants). Altogether 528 cases identified to suffer from severe head injury (GCS < or = 8 or deteriorating to that level within 48 hrs) were enrolled following admission to the hospital and establishment of the diagnosis. Further, patients dying on the scene or during transport to the hospital were also documented, particularly as to the frequency of severe head injury as underlying cause of mortality. The analysis included also cases with additional peripheral trauma (polytrauma). The efficacy of the logistics and organization of the management was studied by documentation of prognosis-relevant time intervals, as for example until arrival of the rescue squad at the scene of an accident, until intubation and administration of fluid, or upon hospital admission until establishment of the CT-diagnosis and commencement of surgery or transfer to the intensive care unit, respectively. The severity of cases studied in the present analysis is evident from a mortality of far above 40% of cases admitted to the hospital, which was increased by about 20% when including prehospital mortality. The outcome data notwithstanding, the emerging results demonstrate a high efficacy of the pre- and early clinical management, as indicated by a prompt arrival of the rescue squad at the scene, a competent prehospital and early clinical management and care, indicative of a low rate of avoidable complications. It is tentatively concluded on the basis of these findings that the patient prognosis is increasingly determined by the manifestations of primary brain damage vs. the development of secondary complications.

Inducible nonviral gene expression in the treatment of osteochondral defects

OBJECTIVE

The repair of osteochondral defects with chondrocytes genetically modified to express desired growth factors promises great potential in orthopaedic therapy. Controlled expression of the transgenes is required in many instances. The objective of the present study was to demonstrate the inducibility of tetracycline-responsive transgene expression in osteochondral defects in the knee joint filled with genetically modified chondrocyte implants.

METHODS

An expression plasmid containing the lacZ gene under the control of the minimal CMV promoter fused to the Tet-responsible element (TRE) as well as the reverse transactivator (rtTA2s-M2) was constructed and used to transfect isolated articular chondrocytes from New Zealand white rabbits. rtTA2s-M2 binds to the TRE in the presence of tetracycline and leads to the transcription of the transgene. Different concentrations of DNA and various DNA:lipid ratios were tested to determine best transfection conditions. Transfection efficiency and inducibility were analysed by histochemical analysis and flow-cytometry. To evaluate the system in vivo, collagen-sponges were seeded with transfected autologous chondrocytes and implanted in osteochondral defects in the knees of NZW-rabbits. Gene expression was induced by doxycycline and 3 weeks later, LacZ-expression in isolated knee joints was evaluated in histological sections by X-gal staining.

RESULTS

In vitro 13.5% (+/-1.32) of induced primary chondrocytes were LacZ-positive, while non-induced controls showed a background-staining in 0.6% (+/-0.2). In vivo, upon doxycycline treatment, induction of lacZ-gene-expression could be demonstrated in chondrocytes in 3-week-old, well-integrated implants.

CONCLUSION

For the first time, tetracycline-inducible gene expression is demonstrated to work in the treatment of osteochondral defects. This demonstrates the feasibility for a gene therapy-assisted approach using controlled expression of therapeutic growth factors from transplanted genetically modified chondrocytes.

Retrograde cartilage transplantation on the proximal and distal tibia

The authors, with experience with more than 400 osteochondral autograft transplantation (OATS) cases since 1996, report a new technique of a retrograde osteochondral autograft transplantation for the treatment of isolated osteochondral lesions of the proximal and the distal tibia started in 1999. We treated 5 patients, 3 who presented with painful traumatic chondral defects in the central weight-bearing portion of the tibial plateau (1 in the medial and 2 in the lateral compartment), and 2 who presented with painful chondral lesions on the distal tibia. An anterior cruciate ligament (ACL) drill guide positioned in the center of the defect was used to accurately prepare the cartilage surface, in one case arthroscopically and in 4 cases through an open incision. A guide-wire was introduced and drilled through the tibia, and a cannulated reamer equal to the diameter of the defect was advanced. An osteochondral cylinder was harvested from the non-weight-bearing zone of the femoral trochlea at the angle that corresponded to the angle on the ACL drill guide. The autograft was inserted in a retrograde fashion from the cortical window into the tibial tunnel to be flush with the articular surface in press-fit technique. The remaining tunnel defect between the cortical window on the tibia and the distal aspect of the autograft was filled with a cancellous bony cylinder and secured with a diagonal bioabsorbable screw. A concomitant varus deformity with the lesion on the medial tibial plateau was corrected in the same surgery using a high tibial osteotomy to relieve stress on the graft. Patients were followed up for 6 to 35 months. A complete healing of the grafts was seen in control magnetic resonance images (MRIs). All patients were satisfied with the surgery. Control arthroscopies showed the osteochondral cylinders well integrated and flush with the articular surface.

Gene transfer of heterologous G protein-coupled receptors to cardiomyocytes: differential effects on contractility

In heart failure, reduced cardiac contractility is accompanied by blunted cAMP responses to beta-adrenergic stimulation. Parathyroid hormone (PTH)-related peptide and arginine vasopressin are released from the myocardium in response to increased wall stress but do not stimulate contractility or adenylyl cyclase at physiological concentrations. To bypass the defective beta-adrenergic signaling cascade, recombinant P1 PTH/PTH-related peptide receptors (rPTH1-Rs) and V(2) vasopressin receptors (rV(2)-Rs), which are normally not expressed in the myocardium and which are both strongly coupled to adenylyl cyclase, and recombinant beta(2)-adrenergic receptors (rbeta(2)-ARs) were overexpressed in cardiomyocytes by viral gene transfer. The capacity of endogenous hormones to increase contractility via the heterologous, recombinant receptors was compared. Whereas V(2)-Rs are uniquely coupled to Gs, PTH1-Rs and beta(2)-ARs are also coupled to other G proteins. Gene transfer of rPTH1-Rs or rbeta(2)-ARs to adult cardiomyocytes resulted in maximally increased basal contractility, which could not be further stimulated by adding receptor agonists. Agonists at rPTH1-Rs induced increased cAMP formation and phospholipase C activity. In contrast, healthy or failing rV(2)-R-expressing cardiomyocytes showed unaltered basal contractility. Their contractility and cAMP formation increased only at agonist exposure, which did not activate phospholipase C. In summary, we found that gene transfer of PTH1-Rs to cardiomyocytes results in constitutive activity of the transgene, as does that of beta(2)-ARS: In the absence of receptor agonists, rPTH1-Rs and rbeta(2)-ARs increase basal contractility, coupling to 2 G proteins simultaneously. In contrast, rV(2)-Rs are uniquely coupled to Gs and are not constitutively active, retaining their property to be activated exclusively on agonist stimulation. Therefore, gene transfer of V(2)-Rs might be more suited to test the effects of cAMP-stimulating receptors in heart failure than that of PTH1-Rs or beta(2)-ARS: