Published online Dec 18, 2017. doi: 10.5312/wjo.v8.i12.935
Peer-review started: September 21, 2017
First decision: October 23, 2017
Revised: November 1, 2017
Accepted: December 3, 2017
Article in press: December 3, 2017
Published online: December 18, 2017
Trochlear dysplasia is an important and frequent instability factor in patients with recurrent patella dislocations. These patients typically have an insufficiency of the medial patellofemoral ligament (MPFL), which is an additional instability factor. During a trochleoplasty, the articulation of the patella is changed to a more dorsomedial position, which might worsen the insufficiency of the medial soft tissue restraints. All these patho-biomechanical conditions are relevant for a symptomatic instability and should therefore be addressed during surgery. Despite its relevance, studies on combined concepts to address all pathological conditions are rare.
Regardless of whether a MPFL reconstruction is performed as an isolated surgery or as in combination with a trochleoplasty, an adequate tensioning of the graft is a key problem during these surgical procedures. Thus, an overtensioning might lead to stiffness, pain, cartilage degradation, arthrosis and patella fractures, whereas an undertensioning leads to persistent instability complaints. Authors’ technique, which provides an adequate graft tensioning, appears to be helpful to solve these problems. Thus, the study presented here was a necessary first step in exploring authors’ method, which seems to provide reasonable advantages.
To realize a combination of authors’ technique of a balanced MPFL reconstruction to the bony alignment procedure, authors modified both, the technique and especially the approach of the Bereiter trochleoplasty as well as authors’ recently published technique of a balanced MPFL reconstruction. To evaluate authors’ method, 33 knees with with recurrent patellar dislocations and a trochlear dysplasia were evaluated after a mean follow-up of 29 mo.
To assess the outcome of authors’ modified technique, the Kujala, IKDC and Lysholm scoring were evaluated. Moreover, patients’ satisfaction with the general outcome, the return to sports, the cosmetic outcome, the pre- and postoperative pain and a potential avoidance behaviour were assessed.
The preliminary clinical results of this technique demonstrate a good efficiency in relieving the symptoms and improving the function of the affected knee. There were no signs of a persistent instability. A significant pain reduction and a significant improvement at the Kujala, Lysholm and IKDC scoring is demonstrated. 94% of the patients were very satisfied with the clinical and cosmetic outcome of the surgery. 92% of the patients who were engaged in regular physical activity before surgery returned to full sporting activities. In regard to three patients showing a slight flexion deficit compared to the contralateral side at the last follow-up, authors changed the postoperative treatment protocol. Thus, authors do not limit the flexion any more post-operatively and authors try to ensure intensive motion exercises. One patient did not return to sports and another patient, who was not active in sports before surgery, still did not participate in regular physical activity after surgery. Both reported that this was related to a persistent avoidance behavior and not instability- and/or pain-related. This specific problem, which reduced authors’ return to sports rate, might highlight the need for an intensive individual sports therapy.
In patients with a symptomatic patellar instability, both a trochlear dysplasia and an insufficiency of the MPFL should be addressed during surgery. Regarding the literature, an inadequate graft tensioning is one of the most important reasons for complications during MPFL reconstruction such as stiffness, pain, cartilage degradation, arthrosis, patella fractures, etc. Therefore, authors’ balanced MPFL reconstruction technique might optimize the alignment of the medial soft tissue restraints with a correspondingly low incidence of complications. The authors technique is a practicable solution to achieve a feasible correction of the bony dysplasia combined with a balanced alignment of the medial soft tissue restraints. Thus, authors’ technique shows a reliable stabilization of the patellofemoral joint and a low incidence of complications. The results in common clinical outcome scorings as well as in terms of pain, return to sports and patient satisfaction are encouraging. To realize a simple combination of authors’ recently published techniques of a balanced MPFL reconstruction with sulcus deepening trocheloplasty, authors modified both techniques. Especially the described approach to the medial margin of the patella, the medial retinaculum and to the trochlear groove appears very feasible. On the one hand, the study presented here was a necessary first step in exploring authors’ modified method, which seems to provide reasonable advantages. On the other hand, this study gives an original insight to the patients‘ outcome. Besides the assessment of the commonly used scorings and the incidence of complications, this investigation gives a deeper insight to understand the outcome in terms of pain, cosmetic results, patient satisfaction and the return to sports. This might give us a better understanding of the patients‘ expectations and the role of physio- as well as an individual sports therapy. Because both trochlear dysplasia and an insufficiency of the medial soft tissue restraints are relevant for a symptomatic patellar instability, a method which addresses both patho-biomechanical conditions might be a good solution. A balanced medial soft tissue reconstruction might optimize the procedure. To combine authors’ technique of a balanced MPFL reconstruction to the bony alignment procedure, authors modified both the technique and especially the approach of the Bereiter trochleoplasty as well as authors’ MPFL reconstruction technique. Authors’ balanced MPFL reconstruction technique might help to get an adequate alignment of the medial soft tissue restraints. Besides the assessment of the commonly used outcome scorings, this study gives a better understanding of the outcome in terms of pain, cosmetic results, patient satisfaction and the return to sports. A new phenomenon author noticed in two patients was a persistent avoidance behaviour for typical stress situations during sports. Even if both patients reported that this was not instability- and/or pain-related, this behaviour interfered with their return to sports. Even if this phenomenon was seldom, these findings might highlight the need for an intensive physiotherapy as well as the need of an individual sports therapy. The modified technique shows encouraging results in terms of a sufficient stabilization of the patellofemoral joint, a low incidence of complications and a good outcome in terms of pain, cosmetic results and return to sports. The preliminary clinical results of authors’ technique demonstrate a good efficiency in relieving the symptoms and improving the function of the affected knee. Therefore, authors will continue this method in the future when indicated. In three patients, authors noticed a slight flexion deficit at the last follow-up. Considering this phenomenon, authors changed the postoperative treatment schedule to a protocol without any postoperative limitations of flexion. Furthermore, authors will try to ensure intensive postoperative motion exercises by using continuous passive motion devices, etc.
The comparatively good outcome presented in authors’ study should not be taken for granted. The need for an individual postoperative physio- and sports therapy is also outlined in this study. A larger clinical outcome study with longer follow-up periods is needed to investigate long-term outcome results of authors’ methods. This will assess the durability of the clinical results. Furthermore, data on the prevention of a secondary arthritis are of interest in this patient group, which normally shows high rates of osteoarthritis development. Besides further improvements of the surgical technique, the questions of how to optimize and individualize the postoperative physio- and sports therapy will be of interest. A larger long-term clinical outcome study on the clinical results and the prevention of secondary arthritis will be a useful method for the future research.