Over the years, there has been much debate about the optimum treatment of the type II injury. In Meyers and McKeever’s [19] original description of 35 paediatric patients, type II injuries (n = 17) were treated with aspiration of haemarthrosis and cast immobilisation. Open reduction and internal fixation (ORIF) was reserved for type III injuries only (n = 8). Sixteen of the seventeen type II injuries had an excellent outcome, with the remaining one reporting a good outcome. Interestingly, only five of the eight type III injuries were reported to have an excellent outcome at average follow up of 3 years (range 0.5–20 years). These findings were confirmed by a follow up report just over a decade later by the same authors [26], when they once again demonstrated an excellent outcome with type II injuries treated with cast immobilisation (23 out of 24), and lead them to conclude that all type II injuries can be treated with closed reduction and casting. Despite this long understanding, none operative management has theoretically been associated with non anatomical reduction causing non or malunion, ACL instability and loss of knee range of motion.

Baxter and Wiley [23] reported on 13 type II injuries from a total of 42 patients in their study. Five of these were treated with cast immobilisation, and at follow up (between 3 and 10 years), there was no clinical difference in ACL laxity between the injured and the normal knee. Seven type II injuries were treated with closed reduction and one with open reduction. In both treatment modalities there was a mean difference in anterior translation of the tibia on the femur of 3.5 mm, but this was not associated with clinical instability. Eight of the thirteen (62 %) patients with type II injuries had more than 10° loss of extension, but interestingly the prevalence was greater in type III injuries (81 %), even in those that had an open reduction (52 %) or a closed reduction (41 %). Edmonds et al. [27] compared ORIF, arthroscopic reduction and internal fixation (ARIF) and closed reduction and casting in displaced type II and III injuries. They found 16.7 % of fractures that were treated with closed reduction and casting required subsequent operation for loose bodies, instability and impingement. This subset of patients that required surgery after an initial period of none operative management had a mean displacement of 6.7 mm, which led Edmonds et al. [27] to conclude that displacement of less than 5 mm may be a safe cut-off for non-operative management and a greater displacement is an indication for surgical reduction and fixation. Unfortunately, the small number of subjects involved in this subgroups analysis makes it difficult to extrapolate these results, and there is no indication from Edmonds et al. of how many of these injuries were type II and how many were not.

Another argument for surgical treatment of type II injuries is to remove any soft tissue interposition which could prevent complete fracture reduction. Falstie-Jensen and Søndergård Peterson [28] reported on four cases of meniscal incarceration, which required arthroscopic reduction, three of the four occurring in type II injuries. Other studies have reported rates of soft tissue interposition of between 32 % and 100 % [27, 29] in these injuries. Tudisco et al. [22] argue that accurate initial reduction is the key to a good prognosis, and advocate all type II injuries be treated with surgical reduction and fixation. In their study of 14 patients with mean follow up of 29 years (range 12–42), 3 (21 %) had type II injuries. Two were treated with cast immobilisation alone, and one was treated with ARIF. Post operative care included immediate weight bearing and continual passive motion for 6–10 hrs a day for the first 3 weeks. At follow up all had a full range of motion, but the two treated with cast immobilisation did have signs of clinical instability as demonstrated by the KT-1000 arthrometer. The small numbers in this study preclude any valid conclusions. Gans et al. [30] reported a total of ten non unions in 580 patients, 80 % of which occurred in type II (n = 2) and type III (n = 6) injuries that were treated non-operatively. Although small, the risk of non union seems to be more common in type II injuries treated non operatively than with surgery, and this might support the argument for operative fixation. In addition, they reported a prevalence of knee laxity of 22.2 % as demonstrated by positive anterior draw and Lachman tests, and 7.8 % as demonstrated by positive pivot shift test in subjects that had sustained type I or II injuries. This suggests that a proportion of type II injuries can have residual laxity which might be prevented by surgical fixation. This would need to be explored further through the use of controlled trials. What is not in doubt is the significant difference in these measures of laxity that are seen in type III and type IV injuries. Gans et al. [30] reported these rates to be between 40 % and 60 %.

The study by McLennan [31] was one of the first published on the use of arthroscopy in the treatment of these injuries. He reported on 35 type III injuries, and used arthroscopy to reduce the fracture fragments which were then held with either cast immobilisation or percutaneous K-wires. Patients with isolated tibial spine fractures treated this way were able to return to pre injury function between 3 and 4 months after surgery. McLennan claimed that arthroscopic assisted reduction helped to reduce hospital stay and rehabilitation time, but his study had no control group to compare with. Since then, other authors have gone on to show that arthroscopic surgery for type II-IV injuries can achieve good outcomes including functional knee scores, range of motion and low rates of non union [32].