Minimally invasive opening wedge tibia outpatient osteotomy, using screw-to-plate locking technique and a calcium phosphate cement

Early experience using patient-specific instrumentation in opening wedge high tibial osteotomy

PURPOSE

Patient-specific instruments (PSI) have been designed to improve the accuracy of performing opening-wedge high-tibial osteotomies (OW-HTO). This study aims to evaluate the lower limb alignment, by comparing pre-operative desired correction to post-operative achieved correction, the difference in surgical time and number of radiological exposures in OW-HTO using patient-specific instruments (PSI) versus conventional osteotomies and the specific and non-specific complications that occurred.

METHODS

We performed a single-centre, retrospective, observational study, including 25 consecutive patients undergoing OW-HTO using PSI, from January 2019 to October 2020.

RESULTS

Pre-operatively, the mean hip-knee angle (HKA) was 167°, the mean tibial slope was 7.9° and the mean medial proximal tibial angle (MPTA) was 82.5°. Post-operatively, the mean HKA was 182.2° (180.1-184.7°), the tibial slope was 6.5° (4.2-12.9°) and the MPTA was 92.8° (90.6-93°). In both coronal and sagittal plane, all knees were within 2° from the planned value. The mean tourniquet time, by which the surgical time was measured, was 40 minutes and the average number of intra-operative fluoroscopic images was 10 (range: 7-14), significantly less than when using conventional techniques.

CONCLUSIONS

The use of PSI in OW-HTO allows accurate achievement of the desired correction, while shortening the OR time. The number of radiological exposures is also decreased, in comparison with the conventional osteotomies.

Type of bone graft and primary diagnosis were associated with nosocomial surgical site infection after high tibial osteotomy: analysis of a national database

PURPOSE

Although several small-scale studies have reported risk factors for surgical site infection (SSI) after high tibial osteotomy (HTO), no study has collectively analysed risk factors in a large cohort. The present study aimed to clarify the risk factors for SSI after HTO using a national database.

METHODS

Data of inpatients who underwent HTO from 2010 to 2017 were obtained from the Diagnosis Procedure Combination database in Japan. Outcome measures were the incidence of SSI and deep SSI after HTO. Associations between SSI and patient data were examined with multivariable logistic regression analysis.

RESULTS

Among 12,853 patients who underwent HTO, 195 developed SSI (1.52%) and 50 developed deep SSI (0.39%). Univariate analysis showed that male sex, smoking, and longer anaesthesia duration were associated with higher incidences of SSI, whereas a primary diagnosis of osteonecrosis and use of natural bone grafts were associated with lower incidences. In multivariable analysis, SSI was positively associated with male sex, anaesthesia duration longer than 210 min (vs. 150-210 min), and use of artificial bone graft (vs. natural bone graft). SSI was negatively associated with age ≤ 49 years (vs. 50-59 years) and a primary diagnosis of osteonecrosis (vs. osteoarthritis).

CONCLUSION

The present study revealed novel risk factors for SSI after HTO that previous studies have failed to find, including use of artificial bone graft and longer anaesthesia duration; primary diagnosis of osteonecrosis and younger age were novel protective factors. These findings will help surgeons assess risks of SSI after HTO in individual patients.

LEVEL OF EVIDENCE

III.

A protective hinge wire, intersecting the osteotomy plane, can reduce the occurrence of perioperative hinge fractures in medial opening wedge osteotomy

PURPOSE

A recent study reported that positioning a K-wire to intersect the cutting plane at the theoretical lateral hinge location increases the lateral hinge's resistance to fracture during the opening of opening wedge high tibial osteotomy (OWHTO). The purpose of this study was to evaluate the clinical relevance of the use of this K-wire and its benefits in terms of lateral hinge protection during OWHTO in daily practice.

METHODS

A retrospective comparative study identified 206 patients who underwent OWHTO from January 2014 to December 2017. Among these patients, 71 had an additional K-wire (HK + group), whereas 135 did not (HK- group). The subjects meeting the inclusion criteria were included in a matched pairing process, which identified 60 patients in the HK + group and 60 patients in the HK- group. Mean follow-up time was 2.3 ± 1.0 years (range 2-4.2). Radiographic outcomes were evaluated with intraoperative and postoperative fluoroscopic imaging and with CT imaging at 6 weeks post OWHTO surgery. The knee osteoarthritis outcomes score (KOOS) was used and time needed to return to work and any kind of sports was collected.

RESULTS

Thirty six patients (30%) were found to have a LHF. Among these patients, 26 (72%) did not have an additional K-wire positioned at their theoretical lateral hinge location (HK- group) during the procedure. LHF rate for patients without additional K-wire group (HK-) was 43.3%, whereas it was 16.7% for the patients with an additional K-wire (HK +) [Odd ratio 3.8 95% CI 1.6-8.3; p = 0.005]. The mean time to return to work, return to any kind of sports, and bone union was significantly shorter for HK + group (p < 0.05).

CONCLUSION

This study demonstrated that during OWHTO, positioning a K-wire intersecting the cutting plane at the theoretical lateral hinge location reduced the number of intraoperative lateral hinge fractures.

LEVEL OF EVIDENCE

III retrospective case-control study.