Developmental dysplasia of the hip (DDH) is rarely encountered in the native sub-Saharan African population. We present a retrospective review of the incidence of symptomatic DDH in Malawi and a systematic review of the role of back-carrying as a potential influence of prevalence in this population group. We retrospectively reviewed the diagnosis and management of all infants seen at the Beit CURE International Hospital, Malawi and its mobile clinics, from November 2002 to September 2012. In addition, methodical review of the literature using the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist and algorithm was performed. A total of 40,683 children aged less than 16 years were managed at our institute over a 10-year period, of which 9842 children underwent surgery. No infant presented with, or underwent surgical intervention, for symptomatic DDH. The majority of mothers in Malawi back-carry their infants during the first 2 to 24 months of life, in a position that is similar to that of the Pavlik harness. We believe this to be the prime reason for the low incidence of DDH in the country. In addition, there is established evidence indicating that swaddling, the opposite position to back-carrying, causes an increase in the incidence of DDH. There is a need for the establishment of a large clinical trial into back-carrying and prevention of DDH in non-African population groups. Level II.

Aims: Functional alignment (FA) and adjusted mechanical alignment (aMA) are recognized techniques for performing total knee arthroplasty (TKA). The native femur rolls back further on the lateral tibial plateau than the medial side during flexion, resulting in a medial pivot pattern of movement. We have assessed whether an individualized alignment technique affects the kinematic pattern observed and the clinical outcomes, when compared to a systematic alignment technique in TKA.Methods: A total of 60 consecutive patients were randomized to a robotically assisted TKA with either FA (n = 29) or aMA (n = 31), using a cruciate-retaining (CR) implant. After definitive implantation of the prostheses, a trial pressure monitor was inserted recording contact points between the femoral component and monitor in the medial and lateral compartments as the knee was taken through a range of motion. The kinematic pattern was observed, contact pressures measured, and patient-reported outcome measures (PROMs) assessed at 12 months.Results: The FA-TKA group produced a medial pivot in 58.6% of cases (17/29), symmetrical rollback in 37.9% (11/29), and a lateral pivot in 3.4% (1/29). The aMA-TKA group produced a medial pivot in 19.4% of cases (6/31), symmetrical rollback in 45.2% (14/31), and a lateral pivot in 35.5% (11/31) (p < 0.001). No differences in knee balance were recorded between the two alignment groups at any flexion point. Patients with a medial pivot kinematic pattern had superior one-year PROMs in some measures. Patients producing a lateral pivot had lower Kujala scores.Conclusion: FA CR-TKA generates an intraoperative medial pivot kinematic pattern through soft-tissue balance more often than those that use aMA. Lateral pivot kinematic patterns are more commonly found with aMA. These intraoperative kinematic patterns are related to clinical outcomes, with knees producing a medial pivot performing better than those with lateral pivot.Cite this article: Bone Joint J 2025;107-B(4):423–431.

Aims: Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) have both been shown to be effective treatments for osteoarthritis (OA) of the knee. Many studies have compared the outcomes of the two treatments, but less so with the use of robotics, or individualized TKA alignment techniques. Functional alignment (FA) is a novel technique for performing a TKA and shares many principles with UKA. Our aim was to compare outcomes from a case-matched series of robotic-assisted UKAs and robotic-assisted TKAs performed using FA.Methods: From a prospectively collected database between April 2015 and December 2019, patients who underwent a robotic-assisted medial UKA (RA-UKA) were case-matched with patients who had undergone a FA robotic-assisted TKA (RA-TKA) during the same time period. Patients were matched for preoperative BMI, sex, age, and Forgotten Joint Score (FJS). A total of 101 matched pairs were eligible for final review. Postoperatively the groups were then compared for differences in patient-reported outcome measures (PROMs), range of motion (ROM), ability to ascend and descend stairs, and ability to kneel.Results: Both groups had significant improvements in mean FJS (65.1 points in the TKA group and 65.3 points in the UKA group) and mean Oxford Knee Score (OKS) (20 points in the TKA group and 18.2 in the UKA group) two years following surgery. The UKA group had superior outcomes at three months in the OKS and at one year in ROM (5°), ability to kneel (0.5 points on OKS question), and ascend (1.3 points on OKS question) and descend stairs (0.8 points on OKS question), but these were not greater than the minimal clinically important difference. There were no differences seen in FJS or OKS at one year postoperatively. There were no statistically significant differences between the groups at 24 months in all the variables assessed.Conclusion: FA-RATKA and RA-UKA are both successful treatments for medial compartmental knee arthritis in this study. The UKA group showed a quicker recovery, but this study demonstrated equivalent two-year outcomes in all outcomes measured including stair ascent and descent, and kneeling.Cite this article: Bone Jt Open 2024;5(12):1123–1129.