International Physiology Journal

International Physiology Journal

International Physiology Journal

Current Issue Volume No: 1 Issue No: 2

Case Report Open Access Available online freely Peer Reviewed Citation

Management of Arthrofibrosis of the Knee after an Arthroscopic Meniscectomy with Paralytic Shellfish Poisoning Toxin. Case Report.

1Department of Traumatology and Orthopaedic, Clinical Hospital, University of Chile.

2Laboratorio Bioquímica de Membrana, Departamento de Fisiología y Biofísica, Facultad de Medicina. Institution: Universidad de Chile.



The purpose of this study is to evaluate the use of paralytic shellfish poisoning toxin in a patient with arthrofibrosis of the knee. Arthrofibrosis is a common complication of knee surgery that tends to manifest itself as a limitation of the musculoskeletal ranges. Paralytic shellfish poisoning toxin has been proposed as an alternative treatment for painful musculoskeletal pathologies.


Use of paralytic shellfish poisoning toxin in arthroscopic menisectomy. Case report.


Three doses of paralytic shellfish poisoning toxin were administered in an intra-articular manner on different days. Functionality, musculoskeletal ranges, pain at rest and pain during motion were evaluated.


The current alternatives for management of arthrofibrosis include the use of oral steroids, physiotherapy, mobilization under anesthesia and the liberation of arthroscopic debris. This case is the first report of the use of paralytic shellfish poisoning toxin. The adverse effects the patient presented coincided with those described in the literature but without the presence of severe reactions.

Improvement in functional tests, progress in musculoskeletal ranges and a decrease in the level of pain were achieved. Adverse effects included parenthesia and a feeling of weightlessness.

Author Contributions
Received 05 Mar 2018; Accepted 14 Apr 2018; Published 20 Apr 2018;

Academic Editor: Rajesh Kumar Kharwar, Kutir Post Graduate College, Chakkey, Jaunpur, UP, India.

Checked for plagiarism: Yes

Review by: Single-blind

Copyright ©  2018  Jaime Hinzpeter,

Creative Commons License     This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Competing interests

The authors have declared that no competing interests exist.


Jaime Hinzpeter, Alvaro Zamorano, Maximiliano Barahona, Germán Möller, Joaquín Espinoza et al. (2018) Management of Arthrofibrosis of the Knee after an Arthroscopic Meniscectomy with Paralytic Shellfish Poisoning Toxin. Case Report.. International Physiology Journal - 1(2):1-6.

Download as RIS, BibTeX, Text (Include abstract )

DOI 10.14302/issn.2578-8590.ipj-18-2018


There are many definitions for arthrofibrosis in the literature; however, one of the most frequently used definitions corresponds to the presence of scar tissue in at least one of the knee compartments which unfavorably affects the range of motion of the joint 1, 2, 3, 4. Arthrofibrosis is a common complication in knee surgery to such an extent that it is the most common complication in reconstructive surgery of the anterior cruciate ligament 1. There are no formal reports in the literature with regards to the incidence in relation to presentations after an arthroscopic meniscectomy.

In most cases, it clinically manifests as a limitation of the musculoskeletal ranges of the knee subjected to surgery, but, it should also be suspected in patients suffering more pain than expected during postoperative rehabilitation 5, 6. In the literature, management alternatives for arthrofibrosis such as the use of oral steroids, physiotherapy, manipulation under anesthesia and surgical procedures such as the liberation of intra-articular debris have been described 5.

Over the past 20 years, there has been significant interest in the use of toxins originating from plants, animals, and even microorganisms which have been administered in animal subjects with the purpose of evaluating their use for diverse clinical conditions. One of the best known is the use of botulinum toxin.

Paralytic shellfish poisoning toxin (Neosaxitoxina) is a biotoxin whose toxicity is a result of its reversible bond with voltage-dependent sodium channels in excitable cells7. These channels are fundamental for the neurotransmission of neuronal synapses and neuromuscular bonds; therefore, the blockage of these two physiological processes through the use of paralytic shellfish poisoning toxin explains its two effects in its clinical administration: pain management and control of muscle hyperactivity (muscle relaxant effect) 8. In recent literature, its safety and efficiency have been proved in its use for diverse painful pathologies 9.

The purpose of this study was to evaluate and describe the clinical results of the administration of paralytic shellfish poisoning toxin in a patient who developed arthrofibrosis of the knee after an arthroscopic meniscectomy.

Clinical Case

A clinical case of a 36-year-old female patient, without morbid background, who presents an acute lesion of the posterior horn of the medial meniscus in the left knee. A knee arthroscopy was performed on April 4, 2017, revealing a white zone lesion that required a partial meniscectomy arthroscopically.

After surgery, the patient presented a deficiency in the flexion and extension of the knee and a poor functional outcome despite 30 sessions of motor physical therapy and pain relief medication. Consequently, a joint mobilization procedure was performed under general anesthesia on June 29, 2017, during which full ranges of motion of the joint were achieved. However, after two weeks and ten sessions of motor physical therapy, and after the mobilization under anesthesia (MUA), the patient achieves a slight improvement in the flexion and extension of the knee and its level of functionality.

An intra-articular infiltration of paralytic shellfish poisoning toxin was proposed as a therapeutic alternative.

Management and Results

A paralytic shellfish poisoning toxin administration protocol was performed in the following manner:

Day 0: (July 20, 2017): infiltration using a syringe with 40 µg of Neosaxitoxina mixed with 100 mg of lidocaine (a 2% / 5ml vial).

Day 12: infiltration using a syringe with 20 µg of Neosaxitoxina mixed with saline solution 0.9%.

Day 49: infiltration using a syringe with 20 µg of Neosaxitoxina mixed with saline solution 0.9%.

A goniometer is an instrument that measures angles, and it was used in this study to measure knee range of motion of the patient.

To assess the functional outcome three internationally validated scales were used: Lysholm Knee Scoring Scale, IKDC Subjective Knee Evaluation Form, Tegner Activity Level Score.

The analgesic effect became evident within the first few minutes of administration when the patient stated that the intra-articular pain, which had been previously present during flexion and extension, had disappeared. However, the patient presented extra-articular pain in musculoskeletal structures (lateral gastrocnemius tendon, goosefoot tendons, among others).

According to the patient's feedback, the analgesic effect of the first injection lasted approximately ten days, the effect of the second infiltration lasted four days and the third dose seven days.

In Table 1, the evaluation of different clinical and functional parameters can be seen after the patient was subjected to a spectrum of therapeutic procedures.

Table 1. Clinical and functional parameters used to compare the response to different therapeutic procedures.
Post- arthroscopy Post-MUA Post- 1st dose Post- 2nd dose Post-3rd dose
VAS at rest 5/10 1/10 1/10 0/10 1/10
VAS flexion 8/10 5/10 3/10 2/10 2/10
Active flexion/passive flexion range 80°/95° 100°/116° 100°/125° 125°/130° 125°/135°
Extension range -5° -2° -2°
Functionality tests  
IKDC 20.7 51.7 71.3 71.7 71.3
Lysholm 27 74 85 85 85
Tegner 0 2 3 3 4

*VAS: visual analogue scale (scale of subjective evaluation of pain intensity, minimum 0, maximum 10).

The adverse effects presented by the patient were minor and appeared within the first 15 minutes of administration. These included, among others, paresthesia of the lips, face, and fingertips, in addition to a sensation of “weightlessness”. These effects ceased within 24 – 48 hrs. after infiltration. The patient did not present severe cardiovascular, respiratory or neuromuscular adverse effects.


This case is the first report of the use of paralytic shellfish poisoning toxin in knee arthrofibrosis treatment. Pain management is fundamental to achieve a range of motion of the joint. Complementing physiotherapy treatment with intra-articular paralytic shellfish poisoning toxin was crucial in order to obtain the clinical result.

Arthrofibrosis is an uncommon but devastating complication after knee surgery. It is defined as the loss of full extension or 15° less of flexion with regards to the contralateral knee after three months of surgery 10.

Mobilization under anesthesia is the most commonly used treatment for arthrofibrosis. Several studies have evaluated its outcomes after a total knee arthroplasty 11, 12, 13, 14, however, the results have been variable. It has been proven that better results are achieved when MUA is performed soon (12 weeks after surgery) 15. Notwithstanding, it is not uncommon for patients to present stiffness even after this procedure. In these cases of poor response, some authors have suggested a second MUA 14. In the present clinical case, the patient achieved full ranges of motion of the joint during MUA procedure, however, the day after, pain during rehabilitation procedure restricted once again the active and passive range of motion. Pain management is crucial to maintaining the range of mobility obtained after MUA.

Other interventions are arthroscopic arthrolysis and corticoid infiltration. The former is the last resort when no range of motion is obtained under anesthesia, or a fibrous tissue is seen in a Magnetic Resonance. It is a surgical procedure which has the disadvantage of being invasive and it is reserved for use when no other treatment has been successful 16. Corticoid injection is widely used, but different studies have shown no satisfactory results, even if used in early stages 17.

In this novel treatment, we use intraarticular administration of Neoxasitoxin 1 month after an unsuccessful MUA. It was very useful in pain control and facilitated the treatment with a physiotherapist, achieving satisfactory results. Another option would be the use of a continuous femoral catheter; however, it has the disadvantage that the patient must have a route during the entire treatment with the ensuing risk of complications, such as infection, and in most parts of the world, it is done in an intrahospital manner 18. On the other hand, intra-articular administration with Neosaxitoxin has a lower risk because it can be administered independently due to its higher time of action in pain control.

With regards to the use of paralytic shellfish poisoning toxin, the safety of its administration in human and animal subjects has been reported 19. Furthermore, Neoxasiton efficiency in pain control and management has proven and it has been tested in different pathology with excellent results in the treatment of diverse clinical conditions such as anal fissures 20, 21, 22, chronic tension headaches 23, and postoperative analgesia for total knee arthroplasties 24. That is to say, it has demonstrated to be highly useful for managing pain in different scenarios. The adverse effects the patient presented coincided with those described in the literature 24, not only regarding the time frame of appearance but in its duration as well.

Within the context of the patient, who under anesthesia achieved practically a full range of passive motion and given that the primary cause for a decrease once again in the range of motion of the joint was due to pain, paralytic shellfish poisoning toxin was prescribed as part of the treatment in order to optimize physiotherapy and in this way, achieve improved functionality.

Given the results observed in the patient, we believe that these were satisfactory with regards to the achievements in musculoskeletal ranges, functionality and pain relief. The development of this case leads us to think that an intraarticular dose of Neosaxitoxin should be applied immediately after MUA for pain control and by this means, achieve successful results in a shorter term. This protocol is the way to follow this line of research.


Arthrofibrosis is a challenging complication to manage in postoperative patients. There is no precise management algorithm; however, there is a consensus that treatment must be commenced as early as possible with pain management being fundamental. We consider paralytic shellfish poisoning toxin to be a safe and useful tool for managing arthrofibrosis. It provides pain relief thus permitting the optimization of rehabilitation.


  1. 1.Mayr H O, Weig T G, Plitz W. (2004) Arthrofibrosis following ACL reconstruction–reasons and outcome. Arch Orthop Trauma Surg. 124, 518-522.
  1. 2.Dandy D J, Edwards D J. (1994) Problems in regaining full extension of the knee after anterior cruciate ligament reconstruction: does arthrofibrosis exist? Knee Surg Sports Traumatol Arthrosc. 2, 76-79.
  1. 3.Klein W, Shah N, Gassen A. (1994) Arthroscopic management of postoperative arthrofibrosis of the knee joint: indication, technique, and results. Arthroscopy. 10, 591-597.
  1. 4.Lobenhoffer P. (1998) Golden standard: patellar tendon-plasty—technique and management of postoperative complications. , Zentralbl Chir 123, 981-993.
  1. 5.Magit D, Wolff A, Sutton K, Medvecky M J. (2007) . , Arthrofibrosis of the knee. J Am Acad Orthop Surg 15, 682-694.
  1. 6.Shelbourne K D, Wilckens J H, Mollabashy A, DeCarlo M. (1991) Arthrofibrosis in acute anterior cruciate ligament reconstruction. The effect of timing of reconstruction and rehabilitation. , Am J Sports Med 19, 332-336.
  1. 7.Golding A L. (2001) Resurgence of sodium channel research. , Annu. Rev. Physiol 63, 871-894.
  1. 8.Lagos N. (1998) Microalgal bloom: a global issue with negative impact in Chile. , Biol. Res 31, 375-386.
  1. 9.Lagos N. (2014) Clinical applications of paralytic shellfish poisoning toxins Gian Paolo Rossini (Ed.). Toxins and Biologically Active Compound from Microalgae, 2,CRC Press,Taylor&Francis Group,NewYork 309-329.
  1. 10.Sander T L, Kremers H M, Bryan A J, Kremers W K, Stuart M J et al. (2017) Procedural intervention for arthrofibrosis after ACL reconstruction: trends over two decades. Knee Surg Sports Traumatol Arthrosc. 25, 532-537.
  1. 11.Fox J L, Poss R. (1981) The role of manipulation following total knee replacement. , J Bone Joint Surg Am 63, 357-362.
  1. 12.Keating E M, Ritter M A, Harty L D, Haas G, Meding J B et al. (2007) Manipulation after total knee arthroplasty. , J Bone Joint Surg Am 89, 282-6.
  1. 13.Yeoh D, Goddard R NicolaouN, Willmott H, Miles K, East D et al. (2012) Butler-ManuelA.Manipulation under anaesthesia post total knee replacement: long-term follow up. Knee. 19, 329-31.
  1. 14.Davis RL FerrelJR, Agha O A, PolitiJR. (2015) Repeat manipulation under anaesthesia for persistent stiffness after total knee arthroplasty achieves functional range of motion. Surg Technol Int. 26, 256-60.
  1. 15.Issa K, Banerjee S, Kester M A, KhanujaHS DelanoisRE, Mont M A. (2014) The effect of timing of manipulation under anaesthesia to improve range of motion and functional outcomes following total knee arthroplasty. , J Bone Joint Surg Am 96, 1349-57.
  1. 16.Rue J P, Ferry A T, Lewis P B, Bach BR Jr. (2008) Oral corticosteroid use for loss of flexion after primary anterior cruciate ligament reconstruction. Arthroscopy. 24, 554-559.
  1. 17.Affas F, Stiller C, Nygårds E, Stephanson N, Olofsson C.A randomized study comparing plasma concentration of ropivacaine after local infiltration analgesia and femoral block in primary total knee arthroplasty. , Scandinavian Journal of Pain 2012, 46-51.
  1. 18.McAlister I, Sems S A. (2016) Arthrofibrosis after periarticular fracture fixation. , Orthop Clin N Am 47, 345-355.
  1. 19.Garrido R, Lagos N, Lattes K, Garcia C, Azolas R et al. (2004) The Gonyautoxin 2/3 epimers reduces anal tone when injected in the anal sphincter of healthy adults. , Biol. Research 37, 395-403.
  1. 20.Garrido R, Lagos N, Lattes K, Abedrapo M, Bocic G et al. (2005) A Gonyautoxin: new treatment for healing acute and Chronic anal fissures. Dis. Colon Rectum. 48, 335-343.
  1. 21.Garrido R, Lagos N, Lagos M, Rodriguez-Navarro A J, García C et al. (2007) Treatment of chronic anal fissure by Gonyautoxin. Colorectal Dis. 9, 619-624.
  1. 22.Lattes K, Venegas P, Lagos N, Rodríguez-Navarro A J, García C. (2009) Local infiltration of gonyautoxin is safe and effective in treatment of chronic tension-type headache. , Neurol. Res 31, 208-233.
  1. 23.Hinzpeter J, Barrientos C, Zamorano Á, Martinez Á, Palet M et al. (2016) Gonyautoxins: First evidence in pain management in total knee arthroplasty.,Toxicon. 1, 180-185.
  1. 24.Lagos N, Andrinolo D. (2000) Paralytic shellfish poisoning (PSP): Toxicology and Kinetics. In: Botana LM, (ed). Seafood and Freshwater Toxin: Mode of Action, Pharmacology and Physiology:Marcel Dekker Inc.New York,NY,USA:.