Change in Femoral Offset after Closed Reduction and Dynamic Hip Screw Osteosynthesis Via Lateral Approach in Patients...

Closed reduction and dynamic hip screw (DHS) osteosynthesis are preferred as joint-preserving therapy in case of medial femoral neck fractures (MFNFs). A change in the femoral offset (CFO) can cause gait abnormality, impingement, or greater trochanteric pain syndrome. It is unknown whether the femoral offset (FO) can be postoperatively fully restored. The aim of the study was to investigate the extent of a possible CFO in hip joints after DHS osteosynthesis in the case of an MFNF.

In this retrospective study, 104 patients (mean age: 71.02 years, men: n = 50, women: n = 54) with MFNF who underwent closed reduction and DHS osteosynthesis were analyzed by postoperative x-rays to assess CFO between the operated (OS) and nonoperated joint side (NOS). The studies covered the time period 2010-2020. A statistical comparison was performed between the mean values of FO between OS and NOS, taking into account patient age, gender, and fracture severity.

All operated hip joints showed a CFO. In 76.0% (79 of 104), the FO decreased (FOD), and in 24.0% (25 of 104), the FO increased (FOI). A critical CFO (>15% CFO) was detected in 52.9% (55 of 104). In hip joints with postoperative FOD, the mean FO between NOS (49.15 mm [±6.56]) and OS (39.32 mm [±7.87]) and in hip joints with postoperative FOI the mean FO between NOS (41.59 [±8.21]) and OS (47.27 [±6.68]) differed significantly (p < 0.001). Preoperative FO (r _S: -0.41; p > 0.001) and caput-collum-diaphyseal angle (CCD; r _S: 0.34; p > 0.001) correlated with postoperative CFO. FOD was found in hip joints with a preoperative FO >44 mm and CCD <134° vice versa FOI in hip joints with a preoperative FO <44 mm and CCD >134°.

Closed reduction and DHS osteosynthesis in patients with MFNF result in a clustered significant CFO. The individual FO should be taken into account pre- and intraoperatively to avoid a postoperative extensive CFO.