Kids knee surgery: A new orthopaedic subspeciality

Rizwan Arshad, Sheba Basheer, Dominic O’Dowd, Nicolas Nicolaou and Fazal Ali

Who is performing kids’ knee surgery? We can all agree why that is an important question to ask, but the reality is that no one had considered this until the BASK/BSCOS steering committee published their report on the management of paediatric soft tissue knee pathology. In a modern healthcare system, where there is a constant drive to centralise and subspecialise services to help improve outcomes, it seems quite strange that prior to this report there was very little information available regarding who is treating paediatric knee pathology.

Figure 1: Hand and wrist radiographs for two different patients both which demonstrate discrepancy between the patients chronological age and skeletal age. The image on the left is a radiograph of a 12 year old who has a bone age of 15 by G&P method. The image on the right is a radiograph of another 12 year old who has a bone age of 10 by G&P method.

The drive for subspecialists initially began in the post-world war 20th century era, primarily to help improve outcomes for patients with war related injuries [1]. Subsequently, subspecialisation has shown to significantly improve patient outcomes and has been a good fit for the modern healthcare model. Breadth of practice has been replaced with depth of practice with more emphasis on a surgeon’s outcome with the underlining principle of ‘getting it right first time’. This being said, paediatric orthopaedic practice in the UK has not quite changed in the same manner as other orthopaedic subspecialties. A paediatric orthopaedic surgeon is still expected to maintain a broad practice when arguably the stakes and the need for better outcomes are much greater than in adults. There are specialist centres in the UK where paediatric subspecialists exist, but their main areas of focus are spine, limb reconstruction, hip preservation and foot and ankle reconstruction. In more recent years, particularly in the USA, paediatric sports knee surgery has become its own entity and is now gaining more recognition across mainland Europe. In the UK, treatment of paediatric knee pathology is primarily provided by adult knee surgeons who have less exposure treating the patient with open growth plates. In addition, techniques are not well supported by the literature as there is a lack of good quality evidence in children.

The report that was published by the BASK/BSCOS steering committee in 2021 included the results of a survey which had 255 responses from members of both societies. Of note, 85% of all respondents said they performed fewer than 10 paediatric ACL reconstructions in the preceding year, 25% of paediatric orthopaedic surgeons said they treat paediatric ACL injuries compared with 85% of adult orthopaedic knee surgeons and only half of respondents assess skeletal age of patients pre-ACL reconstruction. Interestingly, the vast majority of respondents felt the current way we managed paediatric ACL and meniscal pathology was not the correct way moving forward [2].

The general problem

Knee pain in the paediatric population is a common complaint. One in three adolescents will present to their doctor with knee pain [3] before we even consider sports related injuries or congenital abnormalities.

Figure 2: Clinical photo of a child with fibular hemimelia. Ligament reconstruction is often performed for a variety of clinical reasons. Commonly it is done for patients prior to limb lengthening to prevent knee subluxation. An increasing number of these patients also express a desire to maintain a certain level of activity which we can, in part, help them achieved with ligament reconstruction.

The incidence of paediatric knee injuries are also increasing worldwide with much more participation in elite level sport. Young girls in particular are taking up contact sports at unprecedented rates due to increased inclusion and undoubtedly influenced by the recent success of our national teams. In 2022, a survey by Sport England revealed that there was an increase of 100,000 more young girls playing football compared to five years prior. Along with this we have seen a rise in paediatric sports related knee injuries which has had an impact on the health service globally. A recent UK study reported a 29-fold increase in rates of paediatric and adolescent ACL reconstructions over the last 20 years [4]. Managing knee injuries in the paediatric patient presents its own unique challenges. Special considerations need to be made right from the initial consultation. Aside from the obvious anatomical differences in children that need to be appreciated, there is a whole host of psychosocial factors and dynamics that need to be addressed throughout their journey. Post-operative physiotherapy engagement is crucial to the success of surgery. Engagement in children can be challenging and requires specialist physios and tailored protocols. The whole service needs to be tailored specifically for children to improve the chances of success.

Knee pathology in children is not just the adult pathology in smaller dimensions, there are a whole host of conditions that predominantly present in childhood. Congenital conditions can present with fixed dislocations of the tibiofemoral and patellofemoral joints, ligament deficiencies and hypoplastic condyles which can alter the geometry of the mechanical alignment. In addition, conditions such as osteochondritis dissecans, which can also affect the adult population, have a different aetiology and natural history in the skeletally immature population. Management is therefore tailored specifically to these patients. Furthermore, specific complications are unique to the paediatric population and can be as result of disease, injury or surgical intervention. Having the experience and training to be able to deal with these complications is an important part of treating children.

The ACL problem

In recent times, more recognition has been given to the importance of ligament reconstruction in the skeletally immature. Historically the consensus was that young children who suffered ACL injuries could wait until they reached skeletal maturity for surgical management. 40% of the respondents from the BASK/BSCOS survey said they have treated paediatric ACL injuries non-operatively. This was mainly driven by the fact there was very little evidence to show what the long-term outcomes were for children with ligament deficient knees. There was also reluctance from surgeons to intervene surgically as they had little or no experience of reconstructions in the presence of open growth plates. Evidence now clearly shows that ACL deficiency increases the risk of meniscal damage and that reconstruction should not be delayed until skeletal maturity has been reached. A recent study by Kolin et al. state there is a 3% chance per week of medial meniscal tear from time of injury to surgery [5]. Because of the recognised importance of this issue, the BSCOS and BASK joint committee created a report on the management of ACL injuries in the skeletally immature patient which was subsequently published as guidelines by the British Orthopaedic Association Standards for Trauma and Orthopaedics (BOAST) in May 2022.

Figure 3: This is a 13-year-old boy who underwent a trans-physeal ACL reconstruction on his right knee. The left X-ray is one year post-op showing a neutral mechanical axis and the X-ray on the right is two years post-op showing valgus arising from proximal tibia secondary to growth disturbance. His bone age was one year behind chronological age.

Physeal sparing techniques for ligament reconstruction have been well described and are utilised in children where substantial amount of growth remains. Crossing the physis risks growth plate disturbance and this effect is amplified in younger children. Skeletal age is not always akin to chronological age and this can mislead clinicians. There are verified methods that can quantify skeletal age using simple hand and wrist radiographs and this should be used to calculate the amount of remaining growth. The decision to utilise physeal sparing techniques is influenced by these calculations. In addition, the dimensions of the epiphysis should be evaluated to help decide whether an all-epiphyseal reconstruction or an extraphyseal reconstruction is most appropriate.

Figure 4: Intra-operative images showing patient undergoing all epiphyseal ACL reconstruction. Femoral guidewire is inserted using femoral ACL guide.

Figure 5: Arthroscopic images showing complete absence of the ACL in a patient with fibular hemimelia. There is a PCL like structure which is hypoplastic and not anatomical, blending in to the lateral meniscus. This is a likely aberrant and hypertrophied meniscofemoral ligament that has developed.

The physis is not always a hindrance to the paediatric knee surgeon. It can also provide opportunity. Guided growth is the perfect example of how relatively simple it can be to correct coronal malalignment in children that have open physis. In comparison, patients that have reached skeletal maturity would require periarticular osteotomies. Identifying and correcting coronal malalignment early is much easier and safer. Metaizeau described a technique for guided growth, which involves a cannulated screw rather than an O plate6. This works extremely well in cases where ligaments are being reconstructed in close proximity to the physis as it removes the risk of iatrogenic injury to the ligaments during O plate removal.

The patellofemoral disease problem

Patellofemoral instability is a spectrum and is a significant proportion of the problems treated in children. Symptoms range from anterior knee pain secondary to patella maltracking through to recurrent frank dislocations which can become fixed. Chondromalacia patella and Hoffa fad pad impingement are often described as conditions in their own entity but practically they are signs of patella maltracking. Thus, it is important to address the underlying cause. Instability is multifactorial and could be related to the morphology of the knee joint, coronal malalignment, abnormal rotational profile of the lower limbs or generalised ligamentous laxity. An open physis may limit the amount of planned bony reconstruction. However, there are several well described soft tissue techniques which give excellent results. Patella instability in children can be a difficult problem to treat but addressing it early may prevent a lifetime of disability for these patients.

Figure 6: Clinical photograph of Modified Mcintosh procedure for congenital ACL deficiency. The ITB is harvested and detached proximally. It is then tubularised and passed behind the lateral femoral condyle, through the notch, under the inter-meniscal ligament and anchored to the proximal tibia. Further extra-articular anchorage of the graft to the periosteum at the lateral femoral condyle is also performed.

The evidence – or lack of it

Currently there are still lots of unanswered questions in kids knee surgery. There are a number of established techniques which are well evidenced in adults but not for paediatric patients. There is no consensus or gold standard for a significant proportion of the pathology we treat in children. The lack of evidence is multifactorial and is in part due to the current approach to paediatric knee surgery in this country. Specialist centres with dedicated paediatric knee surgeons are leading the way with research. The tailored service they provide in conjunction with volume of patients they treat make it easier for these trials to run. Current studies in paediatric knee surgery include the DimE observational study looking at the treatment of discoid meniscus and the PAPI study looking at operative vs non-operative treatment for first time patella dislocations in the skeletally immature. More evidence is needed in paediatric knee surgery and is likely to improve as we adopt a more subspecialist approach.

Figure 7: Intra-operative images showing Percutaneous Epiphysiodesis using Transphyseal Screws (PETS) technique described by Metaizeau. This procedure was performed in conjunction with patella stabilisation.

The solution

So, who should be performing kids’ knee surgery? The BASK/BSCOS survey showed that over 60% of respondents felt that paediatric ACL and meniscal pathology should receive multidisciplinary care and follow-up with both paediatric orthopaedic and adult knee surgeons. Over 30% felt that these patients should be referred to high volume centres. The current approach to kids’ knee surgery in the UK is less than ideal and this is being highlighted by the clinicians that are currently treating paediatric knee pathology.

Having specially trained paediatric knee surgeons ensures that we bridge the gap between the paediatric orthopaedic surgeons and the adult knee surgeons. Specialist training will allow surgeons to learn soft tissue reconstruction techniques specifically refined for the immature skeleton. It will provide more experience in dealing with the growth plate which will help surgeons prevent and better deal with deformity. Most importantly, it will produce high volume surgeons which is important with regards to patient outcomes and advancing research.

Presently, the only dedicated fellowship in the UK with an emphasis on children’s knee pathology is the Sheffield/Chesterfield Knee Fellowship. This programme was created to address the current issues with paediatric knee surgery. It is important that more of these are developed throughout the country in order to produce the number of surgeons needed to meet the demand. Another strategy that is popular is for surgeons to be double fellowship trained in both adult knee surgery and paediatric orthopaedic surgery.

Figure 8: The kids knee team at Sheffield Children's Hospital (from left to right) Nicolas Nicolaou, Fazal Ali, Dominic O'Dowd, Paul Haslam, Rizwan Arshad (Fellow) and Sheba Basheer (Fellow)

The biennial International Kids Knee Conference provides a great platform for specialists from all over the world to share their expertise and experience in treating child and adolescent knee conditions. The popularity of this meeting has demonstrated the increasing importance that this subspecialty is receiving from the orthopaedic community worldwide.

In essence, kids’ knee surgery is an emerging subspeciality within orthopaedics that will hopefully tackle the current challenges associated with treating knee problems in this age group. Its importance is gaining more recognition worldwide as the incidence of knee injuries in children increases along with the demands for better outcomes.

Figure 9: 2022 International Kids Knee Conference held in Sheffield with Faculty members from UK, Japan, Australia, USA, Chile, Brazil and many European countries. Over 200 delegates attended from all over the world.

References

1. Swarup I, O’Donnell JF. An Overview of the History of Orthopaedic Surgery. Am J Orthop 2016;45(7):E434-E438.

2. Nicolaou N, Ajuied A, Ali FM, et al. The BASK/BSCOS steering committee report on the management of paediatric soft tissue knee pathology, Jan 2021.

3. Rathleff MS, Holden S, Straszek CL et al Five-year prognosis and impact of adolescent knee pain: a prospective population-based cohort study of 504 adolescents in Denmark. BMJ Open. 2019;9(5):e024113.

4. Nogaro M, Abram SGF, Alvand A, et al Paediatric and adolescent anterior cruciate ligament reconstruction surgery. Bone Joint J 2020;102-B(2):239-245.

5. Kolin DA, Dawkins B, Park J et al. ACL Reconstruction Delay in Pediatric and Adolescent Patients Is Associated with a Progressive Increased Risk of Medial Meniscal Tears. J Bone Joint Surg Am 2021;103(15):1368-73.

6. Métaizeau JP, Wong-Chung J, Bertrand H, et al. Percutaneous epiphysiodesis using transphyseal screws (PETS). J Pediatr Orthop 1998;18(3):363-9.

Rizwan Arshad is the current Child, Adolescent and Adult Knee Fellow at Sheffield Children’s and Chesterfield Royal Hospital. He completed his Specialty training in the North Yorkshire Deanery in 2023.

Sheba Basheer is the current National Paediatric Orthopaedic Fellow at Sheffield Children’s Hospital. She completed her Orthopaedic higher surgical training on the North Yorkshire Rotation and was the Child, Adolescent and Adult Knee Fellow at Sheffield Children’s and Chesterfield Royal Hospital from October 2022 to October 2023.

Dominic O’Dowd is a Consultant Orthopaedic Surgeon at Sheffield Children’s Hospital and Rotherham Hospital, specialising in paediatric and adult trauma, knee surgery, sports injuries and injury prevention. He has worked as a doctor at the British Superbikes, with periods as Club Doctor for West Ham United and Blackpool Football Clubs. Internationally he has worked as a Doctor at the England FA with the U1619 Men’s squads as well as the Senior Women’s 2013 World Cup Qualifying Campaign. He has undertaken prestigious sports and paediatric fellowships in Australia and New Zealand including the first dedicated Paediatric and Adult Knee Fellowship.

Nick Nicolaou is a Consultant Paediatric Orthopaedic Surgeon at Sheffield Children’s Hospital, with an interest in Osteogenesis Imperfecta and the Paediatric Knee. He was the Chair of the BASK/BSCOS steering group for paediatric soft tissue knee injuries, current Chair of the BSCOS/BASK Patellofemoral Steering Group, Honorary Secretary for BOSTAA and current Chair of the EPOS sports study group.

Fazal Ali is Consultant Orthopaedic Knee Surgeon at Chesterfield Royal Hospital & Sheffield Children’s Hospital. He completed his Knee Fellowship in Newcastle upon Tyne and travelling fellowships at HSS in New York and Boston Children’s Hospital. He was appointed as consultant in 2004. He is Vice President of BOSTAA, JCIE Chair of Section 1 Exams for all Surgical Specialities and Chair of T&O Joint Surgical Colleges Fellowship Examinations JSCFE.