Currently there is no unanimously accepted stratagem for the treatment of first time patella dislocation, either in the paediatric or adult settings with both conservative and surgical management being popular, in no small part due to the lack of convincing evidence for favouring either approach with several papers giving conflicting evidence and outcomes. The Cochrane review [14] analysed five randomised studies and one quasi-randomised study with a total of 344 patients with first time patella dislocation. Four of the studies included paediatric patients. There was consistent evidence that the surgical intervention group had a significantly lower risk of recurrent dislocation following first time dislocation at 2–5 years follow-up with a relative risk of 0.53 favouring surgery. Given a demonstrative risk of recurrent dislocation in 222 people per 1000 in the non-surgical group, the data equates to 104 fewer people per 1000 having recurrent dislocation after surgical management. Furthermore there was (weaker) evidence of a lower risk of recurrent dislocation after surgery at 6–9 years with 110 fewer patients per 1000 having recurrent dislocation after surgery. However the authors of the review explained that although there was evidence in favour of surgical management in the short term the quality of the evidence was very low as the studies had a high risk of bias due to a lack of blinding and issues with selection and subsequently concluded that ‘the evidence is not of sufficient quality to confirm a significant difference in outcome between surgical or non-surgical initial management’ for first time acute patella dislocation. It is also difficult to generalise this review to the paediatric population as only one of the studies has a paediatric only subgroup [15] and this is specifically acknowledged in the review.

The Nikku [15] study (included in the Cochrane review) child only cohort has subsequently been published as a separate paper by Palmu [16]. This is the only randomised trial in the paediatric literature which compares conservative and surgical treatment in acute patella dislocation. In this study patients under 16 presenting with acute patella dislocation were randomised to conservative management (28 knees) or surgical intervention (36 knees). Patients were followed up for a mean of 14 years with a 94 % follow up rate. The rate of recurrent dislocation was high in both groups (71 % vs 67 %) despite this subjective outcome reporting was favourable with 75 % of conservatively treated patients and 66 % of surgically treated patients reporting a good or excellent outcome at the final follow up – suggesting disconnection between recurrence and patient reported outcomes. There was no significant difference identified between the two groups in subjective reporting, functional assessment or re – dislocation rate at either the 6 year or 14 year follow up points and the authors concluded that surgery does not improve long term outcome and therefore is not advocated for acute patellar dislocation in children and adolescents.

As the Palmu study is the only randomised trial in the paediatric literature there have understandably been no systematic reviews of conservative vs surgical treatment in acute patella dislocation undertaken, however in the adult literature four have been published since 2011 [17], [18] − updated to [19–21]. Mirroring the broader literature on the topic the results are at odds with each other, a recent met-analysis of these papers [22] attempted to assess which of these meta-analyses provides the current best available evidence. They used the Oxman-Guyattn and Quality of Reporting of Meta-analyses systems to assess the quality of the reviews and applied the Jadad algorithm to determine which offered the highest level of evidence. The four studies included 1984 patients with 997 undergoing surgery and the 987 being treated with conservative management. Three studies found that surgically treated patients had a lower re-dislocation rate whereas the other found no difference between the groups. None of the studies found a difference in functional outcome scores between the two treatment groups. The Jadad algorithm determined that the Hing and the Zheng papers offered the highest level of currently available evidence. From this they concluded that although operative treatment may offer a lower rate of re-dislocation than conservative treatment this does not correlate with functional outcome measures.

The majority of the literature assessing the comparison of operative versus non-operative management excludes patients with significant osteochondral lesions and the presence of these represent an indication for surgical management of first time dislocation. This is broadly accepted throughout the literature and is particularly supported in the paediatric population by a French multi-centre study reporting good outcomes for surgical fixation of osteochondral injuries in patella dislocation [23]. Similarly concomitant severe ligamentous injury represent an indication for surgical management and these situations represent a caveat to the approach for simple patella dislocation.

In conclusion the paediatric literature is sparse regarding evidence base for deciding conservative or operative management for acute first time patella dislocation, the only randomised study advocates a conservative approach. The data available in the adult literature whilst suggesting recurrent dislocation is reduced by operative management does not indicate this improves functional outcome and as yet clinical equipoise remains as to the gold standard approach in simple first time acute patella dislocation. A review of anatomical risk factors should be considered to help guide management decisions.

The evidence base behind conservative management is deficient, particularly for the paediatric population. The broad treatment goals are relief of symptoms, preservation of range of motion, enhancement of quadriceps strength and return to previous activity. Classically a short period of immobilisation is instigated to relieve symptoms, followed by formal physiotherapy. There is no firm evidence in the literature to support immobilisation and studies have shown no difference in outcome when comparing immobilisation to none [24]. There have been no randomised trials into physiotherapy regimes [25] and no consensus has been reached on best rehabilitation schedule. Vastus medialis obliquus (VMO) has been suggested as an important target for strengthening after patella dislocation, however a systematic review has found little evidence to suggest that VMO activity can be preferentially enhanced in comparison to vastus lateralis by physiotherapy [26]. It is broadly accepted in the literature that the aim of the conservative treatment whatever form it takes is to avoid chronic muscle weakness and imbalance.

A key consideration in the skeletally immature patient is the proximity of the open physes of the distal femur and apophyses of the tibial tubercle to the site of intervention. Procedures in the armamentarium of the adult surgeon are either not recommended (eg tibial tubercle osteotomies) or modified (MPFL reconstruction) to avoid future growth disturbance.

A multitude of surgical procedures have been described for the treatment of paediatric patella dislocation. These can be divided into lateral release procedures, distal alignment procedures, MPFL reconstructions/medial reefing and trochleoplasty procedures, furthermore combinations of the above can be employed.

Congenital dislocation is a rare entity and this is reflected in the literature with only 2 series addressing its management (Table 12.1). Gordon [36] reported a series of 17 knees with an average age at presentation of 7 years and 9 months. All patients had a fixed unreducible dislocation and all underwent surgery which entailed lateral release, advancement of VMO and in skeletally immature patients medial transfer of the patella tendon, skeletally mature patients had transfer of the tibial tubercle. At follow up all patients had ‘a marked improvement’ in pain and activity tolerance, there was one redislocation. Wada [63] retrospectively reviewed 7 knees in a younger cohort (average age 2.1 years), all knees were treated operatively in combination with lateral release, medial plication, V-Y lengthening of the quadriceps, medial transfer of the lateral patellar tendon and posterior release of the knee. Range of movement was improved in all knees and there was one redislocation. The authors advocate operating at a younger age to achieve the best outcomes.