Peter Lam

Background: The optimal osteotomy technique for severe hallux valgus deformity using minimally invasive surgery remains unknown. This study aimed to explore the clinical and radiographic outcomes between chevron and transverse osteotomies in patients with severe hallux valgus deformity Methods: A retrospective cohort study was conducted including 131 feet (109 patients) with complete radiographic follow-up who underwent hallux valgus correction using either percutaneous chevron and Akin osteotomy (PECA) (n = 43 patients, 50 feet) or metaphyseal extra-articular transverse and Akin osteotomy (META) (n = 66 patients, 81 feet) techniques. Radiographic parameters including hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured at baseline, 6 weeks, and final follow-up. Patient-reported outcome measures were assessed using the Manchester-Oxford Foot Questionnaire (MOXFQ), visual analog scale (VAS) for pain, and EuroQol 5 dimension–5 level questionnaire. Recurrence was defined as a final HVA exceeding 20°. Complication rates and passive correctability were also analyzed. Results: Baseline characteristics were similar between groups, except for significantly higher initial IMA in the PECA group (17.8° vs 15.8°, P = .001). Both techniques achieved significant deformity correction. At final follow-up, the PECA group demonstrated a significantly lower HVA compared to the META group (11.7° vs 14.5°, P = .045), whereas final IMA measurements were similar (5.2° vs 4.9°, P = .642). Recurrence rates were significantly lower in the PECA group (10.0% [95% CI: 4.3%–21.4%] vs 27.2% [95% CI: 18.7%–37.7%], P = .025). Pre-operative passive correctability was significantly higher in the PECA group (68.0% vs 46.9%, P = .020), particularly amongst recurrent cases (80.0% vs 27.3%, P = .047). No significant differences were observed in MOXFQ scores between groups, although VAS pain favored the META group (6.2 [SD 12.3] vs 11.9 [SD 17.5], P = .046). Complication rates were comparable (PECA: 13.2% vs META: 8.6%, P = .40). Complication rates were comparable (PECA: 13.2% vs META: 8.6%, P = .40), with different complication profiles noted between techniques. Conclusion: Both PECA and META techniques provide effective correction of hallux valgus deformity. The higher recurrence rate observed in the META group was associated with a significantly lower rate of pre-operative passive correctability in that cohort. Level of Evidence: Level III, retrospective comparative study.

Background: There has been increasing interest in the percutaneous dorsal closing-wedge Zadek calcaneal osteotomy (PDCWZO) for the treatment of insertional Achilles tendinopathy (IAT). This study aims to investigate the clinical efficacy and radiographic outcomes of the percutaneous dorsal closing-wedge Zadek calcaneal osteotomy in patients with and without pes cavus foot morphology. Methods: A multicentre observational study of patients undergoing PDCWZO for IAT. Patients were stratified into cavus (calcaneal pitch angle > 20 degrees) and non-cavus (calcaneal pitch angle ≤ 20 degrees) groups. The primary outcome was the X/Y ratio and calcaneal pitch angle. Clinical outcomes were assessed using the Manchester-Oxford Foot Questionnaire (MOXFQ), visual analogue scale (VAS) for pain, and EuroQol–5 dimensions (EQ-5D). Between-group analyses were performed to identify differences in outcomes based on foot morphology. Results: Between April 2022 and December 2024, 67 feet (61 patients; 25 male, 36 female) with mean age 55.0 ± 12.7 years (range: 20.9-77.6) underwent percutaneous Zadek osteotomy with a median clinical follow-up of 0.56 years (IQR: 0.48-0.99) and median radiographic follow-up of 0.36 years (IQR: 0.13-0.49). The cohort included 50 cavus feet and 17 non-cavus feet. Radiographic analysis showed a significant increase in the X/Y ratio in both groups (cavus: 2.44 ± 0.27 to 3.08 ± 0.45, P < .001; non-cavus: 2.43 ± 0.28 to 3.05 ± 0.56, P < .001). Calcaneal pitch angle remained unchanged in both the cavus group (27.1 ± 4.2 degrees to 27.1 ± 4.6 degrees, P = .917) and non-cavus group (17.7 ± 1.7 degrees to 18.8 ± 4.8 degrees, P = .270). Clinical outcomes in all groups demonstrated significant improvement in all MOXFQ domains, VAS Pain and EQ-5D ( P < .05). The complication rate was 6.0%. Conclusion: At short-term follow-up (median 6.7 months), percutaneous Zadek calcaneal osteotomy demonstrated a low complication rate and was associated with improvements in foot function and pain relief for patients with both cavus and non-cavus feet. Level of Evidence: Level III, retrospective comparative study.

Background: Minimally invasive surgery (MIS) for hallux valgus correction has demonstrated excellent clinical and radiographic outcomes. However, there are occasions where there is limited bone formation and remodelling despite successful union. This study investigated whether demineralised bone matrix fibre allograft augmentation could be associated with greater radiographic bone formation compared with standard percutaneous technique. Methods: A retrospective comparative study of patients undergoing fourth-generation percutaneous hallux valgus correction with demineralised bone matrix fibre allograft augmentation (DBM group) or without (NDBM group). Primary outcome was radiographic healing assessed at 6 weeks, 3 months, and 6 months using a validated classification system. Secondary outcomes included patient-reported outcome measures (Manchester-Oxford Foot Questionnaire [MOXFQ], EuroQol 5-dimension, 5-level [EQ-5D-5L], visual analogue scale [VAS] Pain), and radiographic parameters (intermetatarsal angle, hallux valgus angle). Results: Between September 2022 and July 2024, a total of 215 patients (191 female; 24 male; 316 feet) underwent fourth-generation percutaneous metatarsal extra-capsular transverse osteotomy for hallux valgus correction. Patients were divided into 2 groups: DBM, 222 feet; and NDBM, 94 feet. Radiographic follow-up was available for 75.2% (167 feet) of DBM and 79.8% (75 feet) of NDBM cases. The DBM group showed significantly improved radiographic union scores at 3 and 6 months ( P = .005-.027) but not 6 weeks ( P = .06). There were no significant differences between groups in terms of final patient-reported outcome measures or radiographic deformity correction ( P > .05). Multivariable regression analysis adjusting for baseline confounders found that DBM was associated with a statistically but not clinically significant improvement in patient-reported outcome measures (PROMs; based on the minimal clinically important difference); however, PROM findings should be interpreted cautiously, given baseline imbalance and approximately 50% loss to follow-up. The additional cost of bone graft augmentation was USD$1780 per procedure. Conclusion: The addition of demineralised bone matrix fibre allograft to the lateral healing zone, was associated with higher radiographic healing scores and a greater proportion classified radiographically as united at scheduled time points following percutaneous hallux valgus surgery. Future studies should investigate whether other biological adjuncts could further optimize healing in specific patient populations or identify those that may not demonstrate bony remodelling.

Background: There has been increasing interest in the use of percutaneous osteotomy techniques for bunionette (tailor’s bunion) correction. This study evaluated clinical and radiographic outcomes following an unfixed, percutaneous oblique distal metaphyseal-diaphyseal osteotomy and compared outcomes between complete and incomplete osteotomy groups. Methods: A total of 43 feet (mean age 54.2 ± 17.1) underwent percutaneous oblique distal osteotomy by a single surgeon over a 4-year period. The primary outcome was the presence of significant postoperative hypertrophic callus at the osteotomy site (>150% of the width of the fifth metatarsal shaft), which decreases over time due to normal bone remodeling. Secondary exploratory outcomes included the radiographic parameters fourth-fifth intermetatarsal angle (IMA) and metatarsophalangeal angle (MPA), and patient-reported outcome measures (PROMs) of Manchester-Oxford Foot Questionnaire (MOXFQ), EuroQol 5-Dimension, 5-Level (EQ-5D-5L), and visual analogue scale (VAS) Pain (minimum 12 months’ follow-up). Results: Thirty feet had a complete osteotomy, and 13 feet had an incomplete osteotomy with the lateral cortex remaining intact. In the complete osteotomy group, 60% of patients ( P = .001) had callus equivalent to >150% of the metatarsal width at 6-week follow up; this reduced to 19% ( P = .31) at 6 months and 0% ( P = 1) at 12 months. No significant hypertrophic callus was observed in the incomplete osteotomy group. All PROMs, except EQ-5D-5L VAS, showed significant improvements ( P < .05). The IMA and MPA significantly decreased postoperatively across both groups ( P < .001). There were no significant differences between the incomplete and complete osteotomy groups at follow-up radiographically and clinically, except for the MOXFQ Walking/Standing Domain ( P = .014), where patients in the incomplete osteotomy group demonstrated greater improvement. Conclusion: Unfixed, minimally invasive oblique distal osteotomy for bunionette deformity is a safe and effective procedure that is associated with significant improvement in radiographic and clinical outcomes. Whether or not the osteotomy is complete does influence hypertrophic callus formation but does not significantly affect the radiographic or clinical outcomes. Level of Evidence: Level III, retrospective comparative study.

Background: Fourth-generation percutaneous, or minimally invasive, hallux valgus surgery utilizes a transverse osteotomy to achieve deformity correction. There are only a small number of studies reporting the clinical and radiographic outcomes of transverse osteotomies, many of which have methodological limitations such as small sample size, limited radiographic follow-up, or use of non-validated outcome measures. The aim of this study was to provide a methodologically robust investigation of percutaneous transverse osteotomies for hallux valgus deformity. Methods: We studied a prospective series of consecutive patients undergoing fourth-generation metatarsal extracapsular transverse osteotomy performed by a single surgeon (P.L.) between November 2017 and January 2023. The primary outcome was clinical foot function assessed using the Manchester-Oxford Foot Questionnaire (MOXFQ), a validated patient-reported outcome measure. Secondary outcomes included the radiographic deformity (the hallux valgus angle [HVA], 1-2 intermetatarsal angle [IMA], and sesamoid position) assessed according to American Orthopaedic Foot & Ankle Society (AOFAS) guidelines as well as a visual analog scale for pain and radiographic evidence of deformity recurrence (defined as an HVA of >20° at final radiographic follow-up). P values of <0.05 were considered significant. Results: Seven hundred and twenty-nine feet (483 patients; 456 female and 27 male; mean age, 57.9 ± 11.9 years) underwent fourth-generation metatarsal extracapsular transverse osteotomy. Radiographic data were available at a vminimum of 12 months postoperatively for 99.7% of the feet, which were followed for a mean of 2.6 ± 1.3 years (range, 1.0 to 5.7 years). There was a significant improvement (p < 0.05) in both the HVA (from 29.5° ± 8.5° preoperatively to 7.3° ± 6.7° at final follow-up) and the IMA (from 12.9° ± 3.3° to 4.6° ± 2.5°). All MOXFQ domains showed significant improvement (p < 0.05), with the MOXFQ Index improving from 36.9 ± 18.9 to 13.4 ± 15.8, Pain improving from 40.5 ± 22.0 to 17.2 ± 18.3, Walking/Standing improving from 32.3 ± 23.1 to 12.0 ± 18.2, and Social Interaction improving from 40.4 ± 20.4 to 11.0 ± 15.2. The recurrence rate was 4.5% (n = 33). The complication rate was 6.1%, which included a screw removal rate of 2.9%. Conclusions: This study, which was the largest consecutive series of any percutaneous osteotomy technique used to correct hallux valgus deformity, demonstrated significant improvement in clinical and radiographic outcomes with a low rate of recurrence. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Minimally invasive hallux valgus surgery can rarely result in a distinct radiologic finding termed the “Filament Union sign,” characterized by a thin, filamentous bone bridge at the osteotomy site .05. Preoperative hallux valgus angle was significantly associated with filament union (odds ratio 1.08, 95% CI 1.02-1.15, P = .006). All cases in the filament union group achieved bony union, with 1 case of nonunion observed in the nonfilament group. No instances of fracture or metalwork failure were observed in the filament union group. Conclusion: The filament union sign is an uncommon radiographic finding following percutaneous hallux valgus surgery, occurring in 3% of cases. Although its presence was associated with statistically significant decreased functional outcomes, this difference did not meet the threshold for clinical significance and was also not associated with an increased rate of mechanical failure/fracture or revision surgery rate. Further research is needed to fully understand the mechanical and biological factors contributing to this pattern of bone healing.

Background: There is increasing interest in the role of pronation as part of the deformity correction in hallux valgus (HV) especially with the advent of weightbearing computed tomography (WBCT) and percutaneous surgical techniques. This study aimed to assess the coronal rotation of the first metatarsal before and after percutaneous distal transverse osteotomy (Metaphyseal Extra-Articular Transverse and Akin Osteotomy [META]) using WBCT and to correlate these findings with clinical outcome scores. Methods: A retrospective analysis of prospectively collected data from a single center of patients who underwent WBCT both before and after percutaneous distal transverse osteotomy for hallux valgus correction. The primary outcome was change in pronation on radiographic parameters; Hallux valgus angle, intermetatarsal angle, metatarsal pronation angle, alpha angle, sesamoid rotation angle, arthritis, and sesamoid position were assessed using coronal WBCT images. Secondary outcomes included pre- and postoperative clinical outcomes, including the Manchester-Oxford Foot Questionnaire (MOXFQ), EuroQol–5 dimensions–5 levels (EQ-5D-5L), visual analog scale (VAS) and complication rates. Results: Fifty-one feet from 34 patients (32 female, 2 male, mean age 60.3 ± 10.2 years) underwent META. Radiographic data were available for 94.4% of feet with a mean follow-up of 12.1 ± 3.2 months. There was a significant improvement across all radiographic parameters including pronation correction ( P < .05). There was also a significant improvement in clinical foot function for all MOXFQ domains, EQ-5D-5L, and VAS pain outcomes ( P < .05). The complication rate was 1.9%. There was no significant correlation of postoperative outcomes with radiographic pronation parameters. Regression analysis did not identify any radiographic or clinical variables that predicted change in the MOXFQ Index domain score. Conclusion: Percutaneous distal transverse osteotomy for hallux valgus deformity can significantly correct coronal plane pronation and improve patient-reported outcomes, although correction of pronation was not significantly correlated with clinical improvement.

Background: Minimally invasive or percutaneous surgery (MIS) for hallux valgus correction has seen increased adoption because of a growing evidence base of positive clinical and radiographic outcomes following surgery. However, no standardized or validated radiographic classification exists to evaluate the first metatarsal osteotomy healing following MIS hallux valgus surgery. The aim was to develop a new radiographic classification system for assessing bone healing following MIS distal transverse osteotomy for hallux valgus. Methods: A 4-domain radiographic classification system based on callus formation, anteroposterior (AP) osteotomy line, lateral osteotomy line, and remodeling for MIS osteotomy healing was developed and tested on a cohort of 27 feet that underwent percutaneous transverse osteotomy for hallux valgus correction. Patients had simultaneous postoperative weightbearing computed tomography (WBCT) and standard radiographs following surgery. Five surgeons reviewed anonymized radiographs to evaluate interobserver reliability. WBCT was used to confirm union status and classification interpretation. Results: The classification system demonstrated substantial interobserver reliability for lateral osteotomy line (Fleiss kappa = 0.671, 95% CI 0.505-0.814) and AP osteotomy line assessment (Fleiss kappa = 0.664, 95% CI 0.459-0.811), with moderate agreement for callus formation (κ = 0.465) and remodeling (κ = 0.439). The classification showed strong correlation with WBCT findings, with an optimal threshold of 8 points identified to differentiate union from nonunion, achieving an overall classification accuracy of 85.2%. This finding was supported by the area under the receiver operating characteristic (ROC) curve of 0.832. At the optimal threshold, the classification demonstrated 90.0% sensitivity and 71.4% specificity for detecting union. Conclusion: This preliminary classification provides a reliable tool for assessing first metatarsal bone healing following MIS hallux valgus osteotomies, with substantial interobserver reliability. It offers a standardized approach for radiographic evaluation, which may enhance comparability across studies and serve as a radiographic research tool pending further validation. Its clinical applicability remains to be determined. Level of Evidence: Level III, diagnostic study.