For many years, successful results have been obtained with the SFO procedure in high dislocated hips [13, 14]. However, in patients applied with SFO, problems are expected such as the risk of non-union in the osteotomy line, infection, dislocation and survival of the short femoral stem in addition to a longer operating time and increased blood loss [15, 16]. Therefore, there is increasing interest from orthopaedic surgeons in without SFO procedures. In the current study of 40 Crowe III/IV patients, high functional scores were obtained without femoral shortening, and no difference was observed in complication rates such as sciatic nerve damage, dislocation and infection. Similarly no difference was observed in rehabilitation and follow-up with similar HHS scores obtained for patients in the controlled femoral cracking group.
Current literature has shown that the hip functional scores of without SFO procedures can be just as good as those of surgical procedures with SFO, and some studies have obtained better results [7, 17, 18]. Mei XL et al compared the results of patients applied and not applied with SFO and reported higher HHS in the patient group not applied with SFO. In a study by Li et al, minimally invasive surgery was planned for Crowe IV patients only, and in the without SFO group, the operating time was found to be shorter and the need for blood transfusion was significantly reduced . As seen in both literature and in the current study, the without SFO procedure in high dislocated hip surgery should be seen as a successful surgical technique, which not only shortens operating time and facilitates the surgery, but also reduces morbidity.
One of the most important advantages of the without SFO procedure is that it allows treatment of LLD. Although limping and LLD is a significant postoperative complaint in high dislocated hip patients, the pain can sometimes be overcome. With the use of the without SFO procedure, LLD has been shown to be corrected to a significant degree [8–11]. In a study by Chen et al, the without SFO procedure was shown to reduce gluteal limping together with correction of LLD . In a series of 38 procedures, Kawai et al reported LLD of mean 3.2 cm (range, 1-5.1 cm) preoperatively and 0.6 cm (range, 0-1.8 cm) postoperatively . Similar to the Kawai study, Wu et al reported LLD correction from 4.3 cm (range, 2.5–5.5 cm) preoperatively to 1.3 cm (range, 0-1.6 cm) postoperatively. However, what amount of LLD is acceptable is not known. Benedetti et al showed that when LLD was 1–20 mm, symmetry was not impaired and hip kinematics were provided . In the current study, although there were no patients with LLD < 2 cm, improvement was seen in the LLD values from 3.4 ± 0.7 cm preoperatively to 0.7 ± 0.5 cm (range, 0–2 cm) postoperatively.
In operations when SFO is not applied, the patient must be thoroughly evaluated in respect of the possibility of nerve damage and excessive soft tissue tension. The most feared complication of surgery without SFO is that sciatic nerve palsy could develop due to the lengthening created. Nerve damage in THA is observed mostly in the sciatic nerve at the rate of 90%. If leg lengthening of > 4 cm is required, it is recommended that the femur is shortened to prevent nerve palsy [21, 22]. To protect against nerve damage, it is recommended that preoperative traction is applied, the operation is performed under general anaesthesia, care is taken in the placement of retractors, and that the postoperative hip position is hip flexion, knee extension. Kong et al recommended the use of neuromonitorisation when necessary to protect against neurological complications . The authors recommended that shortening should be applied when reduction of the true acetabulum is not possible. In the current study, the without SFO procedure was applied to patients where > 4 cm lengthening was not planned, but it can be considered that the osteotomy decision should be made after consideration of additional intraoperative reduction methods.
Hip reduction without SFO is performed with surgical experience and the surgeon develops his own methods. The first stage in reduction is the use of muscle relaxants, for which Yan et al. recommended the intraoperative administration of additional rocuronium . In the current study, surgery was applied to all the patients under general anaesthesia and with muscle relaxant. Another advantage of general anaesthesia over regional anaesthesia is that it allows the evaluation of nerve examination in the early period during patient recovery. As a more invasive reduction method, Kawai et al applied an additional femoral neck cut extending to the level of the trochanter minor in 38 patients and obtained successful results. Wu et al performed additional soft tissue loosening to patients with severe contracture and were able to obtain reduction with no shortening and up to 7 cm lengthening . Lai et al applied surgery without shortening by providing lengthening with the aid of an iliofemoral external fixator. As this method was more invasive and required two surgeons, it was reported to be less favourable than other methods . In a recent study, Li et al described a more minimally invasive reduction method with a Hohmann retractor . In the current study, with the HHS of 88.2 ± 6.3 (84–93) in the controlled femoral cracking group, no decrease was observed (p = 0.750). The advantage of the controlled femoral cracking method described is that it can be applied in a controlled manner according to the degree of intraoperative reduction. It can be considered that by protecting the vertical offset at the same time, this did not cause pathology in the abductor arm and did not create a difference in the functional scores.
The main limitation of this study was that there was no control group for the comparison of hips without shortening. In addition, the number of patients was low and the study was retrospective. That there was no evaluation of the lower back and knees of the patients constitutes another limitation. Although a decrease in knee scores with valgus alignment in the knee joint after without SFO surgery has been reported in the literature, no study could be found which has reported the effect on the lower back. It can be recommended that further studies are planned for evaluation with gait analysis of varying lower extremity biomechanics after surgery without shortening. A strong aspect of the current study was that all the operations were performed by a single surgeon using the same procedure.