In general, complaints in the groin region can be divided into four etiologically relevant categories, whereby there may also be several problems that partly overlap:

• Soft groin problems (Gilmores groin)
• Hip joint problems (e.g. FAI)
• LS / ISJ associated complaints (e.g. herniated disc)
• Functional muscular and neurocoordinative deficits (e. g. adductor muscle-associated groin pain)

All etiologies should therefore always be clarified for affected athletes. In most cases, however, the adductor muscle-induced groin pain is caused by multiple factors.

Significance of the pectineus muscle and the adductors in the hip area

In the case of groin complaints involving the pubic bone branches and the symphysis, there is often a deficit of active pelvic stabilization with a biomechanically induced insertion tendonosis of the adductors. These, among other things, can contribute to the development of the typical edema formation in the area of the pubic bone branches through increased tension, compensatory overstraining and local irritation of the periosteum. The pectineus muscle represents one of the muscles with the largest attachment surface on the pubic bone branch. In addition, it is involved in almost all soccer-specific movements, with its function as adductor, flexor and external rotator, as well as pelvic stabilizer in the standing leg (Fig. 1). It is therefore not surprising that this muscle, in addition to the synergistic adductors, is often overloaded after high levels of stress in footballers and can therefore be palpated with pressure toleration and hypertonia.

It can therefore be assumed that, in addition to the other muscles of the adductor group, it may play a key role in the development and therapy of muscular pubic bone issues.

Possible applications of dry needling and shock waves (ESWT)

Die Local trigger point therapy using special acupuncture needles, known so-called dry needling, has been proven to be an effective and fast-acting method of reducing muscle tone with rapid pain relief in many treatments. Dry Needling is becoming more and more popular in sports medicine and is gradually being scientifically highlighted. A similar effect can also be achieved by the use of shock waves and allows the use by therapists who do not want to or are not allowed to use invasive measures. Practical experience has clearly shown that local therapy of the painful pubic bone alone is not effective. Therefore, it is recommended to work towards a targeted detonation of the essential muscles with shock waves, analogous to dry needling. For this purpose, the adductor muscles can be treated in their entire course at intervals of 2–3 days. The use of the radial shock waves with medium intensity (e. g. EMS Swiss DolorClast, 1.5–2.0 bar with approx. 2500–4000 pulses) is suitable. The diameter of the applicator should be adapted to the individual muscle circumference. For the treatment of adductor muscle-­associated groin complaints, both procedures form a central component of the treatment in order to ensure the best short-term success. This also enables the targeted treatment of deep-seated myofascial trigger points of the pectineus muscle and the surrounding adductor muscles after sonographic and palpatory localization, thus effectively reducing muscle tone after just a few treatments in the medium term. With this treatment, the irritated periosteal bone symphysis complex can be relieved at an early stage in the therapy in order to be able to begin early with functional stabilization in the trunk and pelvic area. In contrast to dry needling, in which the target region is defined by localization and penetration depth (Fig. 2), the penetration depth of the shock waves can be adjusted by varying the applicator diameter and energy (radial shock wave), as well as by using an appropriate forward path (focused shock wave).  

This should be observed in order to reach deeper muscle layers close to the pelvis, such as the pectineus muscle, safely and systematically. A combination of a radial and a focused shock waves have also proven to be successful, as this allows the highly effective width effect of the radial shock wave to be combined with the pinpoint effect and high penetration depth of the focused shock wave. This can take place directly in the temporal sequence, e. g. with a therapist accompanied by a doctor on site or in consultation, but also with a temporal offset (Fig. 3).

Specific training for long-term therapy and prevention

It is widely agreed that purely passive therapy strategies do not solve the underlying biomechanical causes, which are usually based on muscular imbalances, shortening, axial and joint malalignments and disturbed movement patterns due to inadequate or incorrect exercise. Therefore, it is important to carry out a well-founded physiotherapeutic status survey to analyze these parameters of the musculoskeletal system in order to address the identified deficits specifically and individually. An EMG measurement, possibly in addition to a video or movement analysis, can also provide quantifiable data. Experience from professional soccer demonstrates that there are recurring deficits and imbalances which are particularly pronounced in players with groin complaints and are frequently observed. This includes, for example, a lack of control of the lower abdominal muscles in a near-stretch position, as is functionally required in soccer, a relative weakness of the pelvic stabilizing muscles (including the gluteus medius muscle), and a rotational imbalance in the thoracolumbar junction. During active exercise, it is of utmost importance that the deficits are compensated with targeted exercises as they occur in the performance of the functional position in soccer. In practice, it has proved counterproductive to exercise straight and oblique abdominal muscles in a position close to flexion, as is often the case. The goal for soccer is to exercise the full range of motion, especially near the extension, with the upper body stretched or upright (Figs. 4 + 5). Particularly noteworthy is the fact that the targeted active treatment of typical muscular and functional deficits, as described below, is also suitable for prophylaxis. 

In the images below you can see a selection of exemplary exercises with healthy and symptom-free athletes. Whenever possible, how­ever, prophylactic use should also be preceded by a survey of individual functional deficits. In preventive and rehabilitative exercise therapy, the following exercises (Fig. 6–8) have proven to be helpful: 

In cooperation with the Department of Sports Medicine of the Charité – University Medicine Berlin, the results and progressions of the combined therapy of early dry needling and the active exercise concept presented here have been retrospectively collected over the last 5 years in 11 players of the 1st FC Union Berlin e.V.. The pain intensity of the 11 symptomatic players after VAS before treatment was on average 7.00 (5–8; SA: 1.00), the pain duration before the first treatment was on average 36 weeks (1–156; SA: 51.16). On average, 2–3 dry needling treatments (2. 6) of the pectineus muscle were required. The pain level one week after the first treatment was VAS 2.91 (0–5; SA: 1.64). The average number of missed days after the start of treatment were 1.00 (0–10; SA: 3.00) training days and 0.0 match days. The pain level at the time of retrospective assessment (at least 3 weeks after last treatment) was VAS 0.36 (0–2; SA: 0.67). The success of integrating the Core Stability Program into the preventive training of the teams was difficult to quantify. It is worth mentioning, however, that in the five years since the implementation of the program by the club’s medical department, there has been no player downtime for league matches due to persistent groin complaints.

Conclusion

The causes of groin pain in soccer can be many and varied, and therapy is often lengthy. Comprehensive structural and functional diagnostics are the key to successful treatment. In our experience, a combination of the early use of local muscle tone-lowering techniques such as dry needling and shock waves with a targeted active exercise program has proven to be one of many possible treatment methods in practice. At the same time, details in the execution of the exercises, e.g. abdominal muscle training in a sports-specific functional position (close to full extension), can contribute to success.

What is hyaluronic acid?

Hyaluronic acid is a polysaccharide occurring naturally in connective tissue. A special characteristic of hyaluronic acid is its capacity to bind large amounts of water. In joints, it is a principle constituent of synovial fluid and acts as a lubricant, specifically by adjusting its viscosity to the forces acting on it mechanically. It adheres to the joint cartilage in a chemical interaction and is not squeezed out of the joint space under loading, as is often assumed. It also plays a role in regenerative processes in that it widens the intercellular space and thus improves the migration of cells. This is very useful as a chemical property, for example postoperatively in microfracturing.

Hyaluronic acid? ‒ It doesn’t matter which kind of hyaluronic acid you use; it all comes from the same source!

The opinion frequently held by doctors that the hyaluronic acid supplied by different providers is all produced by only one manufacturer (comes from the same source) is incorrect. There are approx. 10 manufacturers globally that produce the raw material. The products do, however, vary in quality, especially in terms of stability. This means that some hyaluronic acid products lose their viscosity after prolonged storage. It is assumed that this has something to do with a barely measurable impurity in the raw material. This is not something the individual doctor can readily check. It is therefore advisable not to store hyaluronic acid products for too long and, if possible, to choose products where the raw material has not been produced in Asia, as these products are likely to be the most unstable.

Does hyaluronic acid really work?

Intra-articular and peritendinous administration of hyaluronic acid is effective. Its efficacy has been demonstrated both for the indication arthritis (e.g. B. Miltner et al. 2012, Petrella et al. 2006) and meniscopathy (e.g. Dernek et al. 2017) and not least for tendinopathy as well (N.Lynen 2012, 40 mg hyaluronic acid and 10 mg mannitol ((Ostenil Tendon)), Gorelick et al. 2015). There are differences particularly regarding its duration of effect. It has been statistically shown that hyaluronic injections can significantly delay the time until endoprosthetic treatment of the knee becomes necessary (Altmann et al. 2015). Proof of efficacy consequently resulted in the inclusion of intra-articular hyaluronic acid therapy in the AWMF [Association of the Scientific Medical Societies in Germany] guideline on arthritis of the knee.

What hyaluronic acid should you use?

Opinions differ sharply on this issue. The differences in quality mentioned above are hard for a treating physician to check. It is equally hard to decide whether to opt for a linear or cross-linked hyaluronic acid or a hyaluronic acid with a high or low molecular weight. There are studies on this issue, but they are often initiated and funded by the manufacturers. It is difficult to find clear answers. A study on a rat model showed that linear hyaluronic acid with an intermediate molecular weight increased cartilage elasticity the most (Gaumet, Badout, Ammann Genf 2018). However, relatively good elasticity values were also achieved in the same study with high-molecular weight cross-linked hyaluronic acid. An important issue to consider is the frequency of injection. With a single administration, the risk of infection from the injection is naturally lower than with an administration given 3 – 5 times. A study by Bannuru et al. in 2015 showed no significant difference in the efficacy or duration of effect between the 5-times administration of hyaluronic acid and the single administration of two products from the same manufacturer. The duration of effect of both products was approx. 6 months. This is also consistent with users‘ current clinical experience.

Should you combine hyaluronic acid with other substances?

This subject was also a matter of very intense debate at the expert meeting in Bad Nauheim. Some users administer local anaesthetics and/or corticosteroids in combination with hyaluronic acid products. A number of studies (Bulstra et al. 1994, Gulihar A. et al. 2013, Farkas B. et al. 2010) have shown that both local anaesthetics, e.g. lidocaine, and corticosteroids, e.g. betamethasone, lead to the death of cartilage cells. In view of the study data, use of local anaesthetics should be very selective. Use of intra-articular corticosteroids should also be considered carefully based on the risk profile. Routine administration in combination with hyaluronic acid is certainly not appropriate. However, there is agreement that hyaluronic acid should not be used to treat an inflamed knee with synovialitis and effusion. In such cases, single administration of corticosteroids is useful. There is high consensus on this procedure in the AWMF guideline on arthritis of the knee under item 4.1.2. At the same time, mention is also made that high-dose corticosteroids can inhibit cartilage cell metabolism and thus damage the cartilage (Hirsch at al. 2013).

Is hyaluronic acid still the gold standard?

Intra-articular hyaluronic acid products have been available for many years and, based on the current study data, are still one of the most important options for the symptomatic treatment of arthritis. A significant effect cannot, of course, be achieved in every patient. And not every patient will experience a lasting effect. However, in routine clinical practice it is important to have a useful option available for symptomatic relief in patients with arthritis that does not yet require surgery. Professional athletes with meniscopathy, for example, can also be helped in this way, as it allows surgical repair of the meniscus to be postponed until the end of the season. Due to the different mechanisms of action, the combined use of hyaluronic acid and platelet-rich plasma is also an increasingly popular option. There is still a lack of valid studies on this. From what was generally said at the expert meeting on arthritis and inflammation management in Bad Nauheim, , the combined use of intra-articular hyaluronic acid and oral UC-II®, i.e. a combination of improved cartilage nutrition and an immunological approach, may be of prospective interest.

Interim conclusion

The administration of intra-articular hyaluronic acid has been and still is an important pillar of the medicinal treatment of arthritis. Our personal experience over the last 20 years tends to favour the 3-5-times administration in a weekly rhythm. The impression of a somewhat higher sustained effect compared to single administration commends multiple administration. However, in elderly and immunosuppressed patients single administration with strict indication is the better option. The variety of the individual hyaluronic products in terms of molecular weight and cross-linking makes comparison difficult. The data available is sometimes inadequate. The user must have confidence in the manufacturers when selecting which product to use. Reputable manufacturers will always be transparent about where the product was produced and filled.

Part II

What is UC-II®?

UC-II® brand is protected by trademark registrations globally covering the proprietary ingredient product which contains undenatured type II collagen. This collagen was harvested by a chemist from chicken sternum. What is special here is that the collagen is not harvested by heating or hydrolysis, which would result in the collagen being denatured and losing its efficacy. This substance is now harvested by a Swiss company (production site in the USA) using a special patented process and is marketed in different oral pharmaceutical forms. Its mechanism of action is interesting as it does not involve high concentrations of a substance that is a structural component of cartilage being present in the joints on oral intake. The effect is thought to arise through the development of oral tolerance due to an interaction between UC-II® and the immune cells in Peyer’s patches in the small intestine. The regulator T-cells formed during this interaction can produce anti-inflammatory cytokines in the joints. These in turn can have a symptom-modulating and repair effect on the joints. A number of studies (Lugo, Saiyed, Lane, Nutrition journal ((2016)), Bagi, Berryman, Lane Osteoarthritis and Cartilage ((2017)) corroborate this propagated effect on rat models and in placebo-controlled trials*. As with hyaluronic acid, which was used at an early stage in veterinary medicine, e.g. in equestrian sport, UC-II® has already been adopted in today’s veterinary practice. It can be considered as a new approach that offers us support in helping our athletes, who often suffer from arthritic changes in their joints early on in their lives. Even if the currently available data for the relatively new substance UC-II® is still limited, the studies have been promising and we will follow and monitor further developments with interest.

*a placebo-controlled, randomised, double-blind study in humans in 2016 showed that UC-II® undenatured type II collagen can improve the well-being, mobility and flexibility of the joints of individuals with OA. It was statistically far more effective than a combination of 1.5 g glucosamine and 1.2 g chondroitin, according to the WOMAC index (Western Ontario and McMaster Universities Osteoarthritis Index).

Radial extracorporeal shock wave therapy (rESWT) was performed with a Swiss DolorClast device and EvoBlue + Power Plus handpiece (Electro Medical Systems S.A., Nyon, Switzerland), and neuroreflectory hyperbaric CO₂ cryotherapy (NHCC) with a Cryolight device (ELMAKO, Iffezheim, Germany).

Case 1: 18-year-old male German Bundesliga youth handball player,five years competitive sports

Patient’s history recurrent with increased strain on both legs since 1.5 years (increased sport and handball intensity); movement and strain pain under the patella on both sides (pain score on the visual analog scale (VAS) from 0 (no pain) to 10 (maximum pain): 6–7); in resting phases pain in regression; physiotherapy performed with temporary pain reduction; continuation of active handball playing with tape bandage despite pain. Three weeks before the first consultation of Dr. René Toussaint (RT) pain already increased during normal walking, climbing stairs and going down; fast walking and jumping very painful; no significant side difference.

Clinical findings (at the time of first consultation of RT) gait pattern disturbance right; 1-toe position possible, but unsafe on right side; local: distinct pressure pain and slight edema in the base region at the lower patellar pole (right > left); reduced patella mobility; isometric pain during knee extension on both sides; no effusion; no ligament instability; no meniscus signs; positive flexion / extension 140 / 0 / 0 on both sides; movement pain; tightly end feeling for flexion on both sides; distinct muscular imbalances with shortening of the front and rear muscle chains of both legs; strength imbalance between knee flexors and extensors on both sides to the disadvantage of knee extensors.

Imaging diagnostics (already performed before consultation of RT) x-ray, sonography, MRI.

Diagnosis patellar tip syndrome on both sides (jumper´s knee; insertion tendopathy of the M. rectus femoris).

Therapy six therapy sessions in total; initial series of 3 therapy sessions each three to four days apart, then therapy-free interval of three weeks, followed by another series of 3 therapy sessions each three to four days apart; rESWT: 5000 radial extracorporeal shock waves (rESWs) per session and side; rESWs generated with the 15-mm applicator and 2 bar @ 15 Hz; rESWT and NHCC applied to the tip of the patella and the patellar ligament on both sides; in addition, NHCC combined with stretching of the M. quadriceps femoris on both sides.

Supportive therapy sport physiotherapeutic intervention at irregular intervals; wearing of sensorimotor insoles in everyday life.

Additional own activities by the athlete eccentric training; muscle training (strengthening, stretching); local ice treatment at irregular intervals; ointment bandages at night.

Time course significant reduction in pain on both sides (VAS 2) after the first series of therapy sessions; no sports leave or modification of sports load possible; increase in stress pain after three weeks due to high sports load (handball) (VAS 4–5), then decision to perform another series of 3 therapy sessions; markedly reduced pain under stress (right knee: VAS 0–1; left knee VAS: 1–2) after the second series of therapy sessions; continuation of sports; last check-up six weeks after the end of the second series of therapy sessions, with full fitness for sport restored and no complaints (especially no pain during exercise).

Case 2: 55-year-old male marathon runner (leisure sport in running group)

Patient’s history ten days before first consultation of RT strain pain in the left calf after a longer run (approximately 15 km); increase in pain 3 days later on the basis of continued running training; afterwards rest pain even without walking load and increasing stretching pain in the left calf in everyday life; extension of the pain symptoms to the entire calf; no subjective muscle weakness in the leg; then pain enhancement in the left calf but also in left thighs already during normal walking as well as climbing and walking down stairs; in addition, swelling of the left lower leg and ankle joint after daily strain.

Clinical findings gait pattern disorder with relief limps on the left side; 1-toe position painfully reduced on the left side; insecure, heel-toe position / gait convertible, but with pain on the left side (lower leg dorsally); distinct pressure pain M. gastrocnemius (middle and distal parts, predominantly mediolaterally (deep) and laterally); strand-like structure palpable without gap or hematoma; calf circumference not increased; regular function of adjoining joints, except of pain during forced maximum dorsal extension of the left foot; muscular dysbalances with distinct shortening of the posterior muscle chain in both upper and lower leg (left > right); no impairment of blood circulation, muscle strength and sensitivity; slight pain-related impairment of muscle strength during plantar flexion of the left foot (Grade 5- according to Janda); no isometric pain; no clinical evidence of Achilles tendon pathology.

Imaging diagnostics exclusion of thrombosis and structural damage (muscle fibre tear) by sonography and MRI.

Diagnosis pulled muscle left M. triceps surae; myofascial trigger points left lateral M. gastrocnemius and left M. soleus.

Therapy six therapy sessions in total; therapy sessions each three to four days apart; rESWT: 5000 rESWs per session; rESWs generated with the 15-mm and 36-mm applicators and 1.6–3.5 bar @ 15 Hz; rESWT applied to the entire left
M. gastrocnemius; NHCC combined with stretching of the left M. gastrocnemius and left M. soleus; kinesiotaping of the left calf.

Supportive therapy physiotherapeutic treatment in the course of gait and running training with dosed, pain-adapted load adjustment.

Additional own activities by the athlete muscle training (stretching); fascia role; compression stockings (Class 2).

Time course significant reduction of pain after the first and second therapy sessions (VAS 2); no running training but modification of strain (cycling, swimming, aqua jogging) to accompany therapy; control examination 3 weeks after the end of therapy: full sporting ability restored; no complaints, in particular no pain in the left calf in everyday life and during a smooth test run, recommendation for gradual build-up of strain; no follow-up visit because of this injury.

Background

The molecular and cellular mechanisms of ESWT on the musculoskeletal system are pretty well understood. Intensive basic research over the last 20 years demonstrated that neurogenic inflammation contributes to the pathology of tendinopathies [1], and ESWs are thought to play a role in the blockade of neurogenic inflammation [2]. Besides this, exposure of tendons to rESWs can stimulate tendon remodelling in tendinopathy by promoting inflammatory and catabolic processes that are associated with removing damaged matrix constituents [3]. Then, induction of the proliferation of fibroblasts [4] may ultimately induce healing. Besides this, a variety of mechanisms of ESWs on muscles were demonstrated in the literature, including selective impairment of end plates at neuromuscular junctions (caused by impairment of acetylcholine receptors) [5], functional angiogenesis / improved blood circulation [6] and enhanced proliferation and differentiation rates of satellite cells [7]. Last but not least improved movement of tendon and fascia gliding against the surrounding tissues by stimulating lubricin expression by ESWs [8] may significantly contribute to myofascial trigger points release by ESWT.

Much less is known about the molecular and cellular mechanisms of neuroreflectory hyperbaric CO₂ cryotherapy (NHCC) on the musculoskeletal system. One potential reason is that this therapy may have been considered just another way to cool down tissue somewhat faster than using ice bags or cold packs. However, recent research has indicated that NHCC primarily and mainly acts on and via the nervous system. 

• Mourot et al. (2007) [9] exposed one hand of healthy people to NHCC and observed a rapid change in skin temperature (from 32.5° ± 0.5°C to 7.3° ± 0.8°C within 90 s) at the treated side, with a statistically significant reduction of the skin temperature at the contralateral side (to 30.5°± 0.6°C). When the authors did the same with an ice bag, the skin temperature changed from 32.5° ± 0.6° C to 13.9° ± 0.7° C at the treated side within 15 min, without significant change at the untreated side. This phenomenon can only be explained by a reaction of the peripheral and central nervous system. Mourot et al. (2007) [9] concluded that NHCC caused a systemic skin vasoconstriction response, whereas the vascular responses triggered by ice bag cooling appeared limited and localized to the cooled area.
• Demoulin et al. (2012) [10] reproduced the findings by Mourot et al. (2007) [9] that NHCC can result in faster and more profound reduction of skin temperature than application of a cold pack.
• Very recently, Kang et al. (2018) [11] divided a total of n=30 patients who had undergone shoulder rotator cuff reconstruction surgery into three groups (n=10 each), and treated them as follows: Group 1: continuous passive motion (CPM) and icing; Group 2: CPM and NHCC; and Group 3: CPM and microcurrent therapy. Each therapy was applied six days for two weeks. Pain, muscle tone near the shoulder area and levels of C-reactive protein (CRP) were tested before and after the interventions. Only the patients in Group 2 showed a statistically significant reduction in CRP levels (from 0.47 ± 0.03 mg / dl before the interventions to 0.28 ± 0.06 mg / dl after the interventions). Differences in shoulder muscle tone appeared only in the supraspinatus muscle, with Group 2 showing the biggest change. Kang et al. (2018) [11] concluded that NHCC may help to stabilize inflammation as well as to reduce pain and muscle tension when applied in patients following rotator cuff reconstruction.

These data indicate that NHCC must not be confused with ice bag / cold pack therapy, and the effects of NHCC are not restricted to the local area of treatment. Particularly the findings by Kang et al. (2018) [11] of significant anti-inflammatory effects of NHCC in postoperative therapy after surgical treatment of the rotator cuff suggest that the true potential of this therapy has so far been underestimated and not properly applied.

Summary

In summary, these case reports indicate that combination of rESWT and NHCC is safe and effective in treatment of painful conditions of the musculoskeletal system of athletes based on misuse and overloading. Future clinical trials are necessary to demonstrate the full potential of this novel combination therapy, and to clearly differentiate NHCC from other therapies with the aim of cooling the skin and underlying tissue (including ice bags, cold packs, air cooling devices, etc.).

You can request a detailed list of references under info@thesportgroup.de

Conflict of interest statement: RT has served as paid consultant for Axxana GmbH (Cologne, Germany), the distributor of the Cryolight device. CS has receiv­ed an unrestricted research grant from Electro Medical Systems S.A. (Nyon, Switzerland), the manufacturer of the Swiss DolorClast device, at LMU Munich, and free loan of a Swiss DolorClast device from Electro Medical Systems GmbH (Munich, Germany) and a Cryolight device from Axxana GmbH for research purposes
at LMU Munich (maintenance and servicing paid by LMU Munich). CS served as paid consultant for Electro Medical Systems until the end of 2017. No other conflicts of interest related to the content presented in this article are reported.