Gonzalez-Bravo, Adrian E.

Aims Heterotopic ossification (HO) is a recognized complication following periacetabular osteotomy (PAO), but its patterns, incidence, and clinical relevance remain poorly defined. The commonly used Brooker classification, developed for total hip arthroplasty, is not fully applicable to HO after PAO. This study aimed to propose a new classification system specific to HO after PAO, evaluate its clinical relevance, and report the cumulative probabilities of radiological and symptomatic HO. Methods This retrospective study included 643 patients who underwent PAO between January 2006 and July 2024. A total of 308 patients (47.9%) had concomitant arthroscopic procedures. Radiographs were analyzed to identify HO using both the Brooker classification and a newly developed system. The cumulative probabilities of radiological and symptomatic HO were calculated using Kaplan-Meier analysis. Difference of variables between patients with and without HO was analyzed. Receiver operating characteristic (ROC) curve analysis was used to compare the predictive performance of the two classification systems. Results The cumulative probabilities of radiological and symptomatic HO at five years post-PAO were 30.4% and 3.8%, respectively. The probabilities were 41.9% in males and 29.2% in females. Four patients (2.8%) required surgical excision of HO, all classified as type 3 or 4 under the new system. The ROC analysis demonstrated superior predictive performance for the new classification system (AUC = 0.928) compared to the Brooker classification (AUC = 0.697; p = 0.007). No significant differences were found between the patients with and without HO in terms of age, sex, concomitant arthroscopic procedures, or receiving prophylaxis in addition to low-dose aspirin. Conclusion This study highlighted the cumulative probabilities of HO following PAO and introduced a new classification system that improved clinical relevance and predictive accuracy. These findings have provided insights into the incidence and management of HO after PAO, and laid the groundwork for standardized reporting and future research. Cite this article: Bone Jt Open 2025;6(11):1436–1445.

AimsPeriacetabular osteotomy (PAO) is a complex procedure for treating hip dysplasia by reorienting the acetabulum to slow osteoarthritis progression. This study aimed to assess the types and rates of complications after PAO and provide recommendations for prevention.MethodsA total of 715 consecutive patients underwent unilateral PAO by a single surgeon between December 2006 and January 2024, with at least one year of follow-up. Indications included hip dysplasia, acetabular retroversion, and protrusio. Hip arthroscopy was performed concurrently in 325 cases. Demographic factors, perioperative data, and complications – graded using the modified Clavien-Dindo system – were analyzed. Risk factors and learning curves were also assessed.ResultsOf the 715 patients, 121 (16.6%) experienced 144 complications. There were 68 grade I, 52 grade II, 23 grade III, one grade IV, and 0 grade V complications. The 23 grade III complications requiring reoperations included four revision PAOs for overcorrection, three fixations for posterior column fracture, four neurolysis procedures for symptomatic lateral femoral cutaneous nerve (LFCN) dysesthesias, four heterotopic bone excisions, and eight wound debridements. All type I and II complications were treated without sequelae. The addition of hip arthroscopy did not increase complication rates. Age < 20 years was associated with a lower risk of complications (odds ratio (OR) = 0.53, 95% CI 0.33 to 0.84, p = 0.008), whereas smoking history (OR = 1.72, 95% CI 1.01 to 2.87, p = 0.040) and correction of both acetabular dysplasia and retroversion (OR = 2.46, 95% CI 1.08 to 5.24, p = 0.024) were linked to an increased risk of complications. The operating time and incidence of complications decreased with increasing experience.ConclusionPAO is an effective procedure with an acceptable complication rate. Risk factors should be discussed during preoperative counselling. While patient optimization may help to reduce complications, precise intraoperative technique remains critical for minimizing risk.Cite this article: Bone Jt Open 2025;6(10):2022–2031.

AbstractHistorically, cementless patellar implants were fraught with issues of fixation and polyethylene wear. However, contemporary cementless patellar implants incorporate modern technologies for implant design and offer the potential for improved biological fixation and longevity. As such, an evaluation of the performance of modern cementless patellae is needed. The purpose of this study was to perform a systematic review and meta-analysis of contemporary cementless patellar implants used during primary total knee arthroplasty (TKA), with a particular focus on aseptic loosening of the patellar component. A systematic review of the literature was performed from January 2000 to February 22, 2024. We included all peer-reviewed studies that reported the number of revisions in patients who had cementless patellae placed in 2000 or later during primary TKA. Reviews and case reports were excluded. Out of 639 studies, 13 were included with a total of 3,005 cementless patellae analyzed. The mean patient age was 64 years and the mean body mass index (BMI) was 31 kg/m2. Meta-analyses were performed to calculate the pooled revision rate per person-year of revision for aseptic loosening of the patellar component and revision for any patellar failure. Upon analysis of 13 studies involving a total of 3,005 cementless patellae, the revision rate for aseptic loosening of the patella was 0.2 per 1,000 person-years and the revision rate for any patellar failure was 1 per 1,000 person-years. Contemporary cementless patellar implants showed an overall revision rate of 1 per 1,000 person-years, demonstrating excellent longevity. The high survivorship, together with a low rate of loosening, show the utility and effectiveness of these implants. Given the nature of biologic fixation, these results are promising for long-term implant stability but additional follow-up is warranted.