Patterns of cartilage loss and anterior cruciate ligament status in end-stage osteoarthritis of the knee

Aims This study aims to determine the proportion of patients with end-stage knee osteoarthritis (OA) possibly suitable for partial (PKA) or combined partial knee arthroplasty (CPKA) according to patterns of full-thickness cartilage loss and anterior cruciate ligament (ACL) status. Methods A cross-sectional analysis of 300 consecutive patients (mean age 69 years (SD 9.5, 44 to 91), mean body mass index (BMI) 30.6 (SD 5.5, 20 to 53), 178 female (59.3%)) undergoing total knee arthroplasty (TKA) for Kellgren-Lawrence grade ≥ 3 knee OA was conducted. The point of maximal tibial bone loss on preoperative lateral radiographs was determined as a percentage of the tibial diameter. At surgery, Lachman’s test and ACL status were recorded. The presence of full-thickness cartilage loss within 16 articular surface regions (two patella, eight femoral, six tibial) was recorded. Results According to articular cartilage loss and ACL status, 195/293 (67%) were suitable for PKA or CPKA: medial unicompartmental knee arthroplasty (UKA) 97/293 (33%); lateral UKA 25 (9%); medial bicompartmental arthroplasty 31 (11%); lateral bicompartmental arthroplasty 12 (4%); bicondylar-UKA 23 (8%); and patellofemoral arthroplasty (PFA) seven (2%). The ACL was intact in 166 (55%), frayed in 82 (27%), disrupted in 12 (4%), and absent in 33 (11%). Lachman testing was specific (97%) but poorly sensitive (38%) for disrupted/absent ACLs. The point of maximal tibial bone loss showed good interclass correlation (ICC 0.797, 0.73 to 0.85 95% confidence interval (CI); p < 0.001) and was more posterior when the ACL was absent. Maximum tibial bone loss occurring at > 55% of the anterior to posterior distance predicted ACL absence with 93% sensitivity and 91% specificity (area under the curve 0.97 (0.94 to 0.99 95% CI; p < 0.001). Conclusion ACL status can be reliably determined from a lateral radiograph using the location of maximal tibial bone loss. According to regions of cartilage loss and ACL status, two-thirds of patients with end-stage knee OA could potentially be treated with PKA or CPKA. Cite this article: Bone Joint J 2020;102-B(6):716–726.

Classification of combined partial knee arthroplasty

Aims There has been a recent resurgence in interest in combined partial knee arthroplasty (PKA) as an alternative to total knee arthroplasty (TKA). The varied terminology used to describe these procedures leads to confusion and ambiguity in communication between surgeons, allied health professionals, and patients. A standardized classification system is required for patient safety, accurate clinical record-keeping, clear communication, correct coding for appropriate remuneration, and joint registry data collection. Materials and Methods An advanced PubMed search was conducted, using medical subject headings (MeSH) to identify terms and abbreviations used to describe knee arthroplasty procedures. The search related to TKA, unicompartmental (UKA), patellofemoral (PFA), and combined PKA procedures. Surveys were conducted of orthopaedic surgeons, trainees, and biomechanical engineers, who were asked which of the descriptive terms and abbreviations identified from the literature search they found most intuitive and appropriate to describe each procedure. The results were used to determine a popular consensus. Results Survey participants preferred “bi-unicondylar arthroplasty” (Bi-UKA) to describe ipsilateral medial and lateral unicompartmental arthroplasty; “medial bi-compartmental arthroplasty” (BCA-M) to describe ipsilateral medial unicompartmental arthroplasty with patellofemoral arthroplasty; “lateral bi-compartmental arthroplasty” (BCA-L) to describe ipsilateral lateral unicompartmental arthroplasty with patellofemoral arthroplasty; and tri-compartmental arthroplasty (TCA) to describe ipsilateral patellofemoral and medial and lateral unicompartmental arthroplasties. “Combined partial knee arthroplasty” (CPKA) was the favoured umbrella term. Conclusion We recommend bi-unicondylar arthroplasty (Bi-UKA), medial bicompartmental arthroplasty (BCA-M), lateral bicompartmental arthroplasty (BCA-L), and tricompartmental arthroplasty (TCA) as the preferred terms to classify CPKA procedures. Cite this article: Bone Joint J 2019;101-B:922–928.

Bicompartmental Knee Arthroplasty (BKA) in comparison to unicompartmental (UKA), Patellofemoral (PFA) ans total knee arthroplasty (TKA) – Early Clinical Results

Aims and Objectives: The purpose was to evaluate the clinical outcomes of patients with knee osteoarthritis treated with bicompartmental arthroplasty (BKA) in comparison to unicompartmental (UKA), patellofemoral (PFA) and total knee arthroplasty (TKA) in a single center. Materials and Methods: This is a prospective study analyzing a consecutive series of 396 patients from two surgeons in a single center. In 191 men and 205 women either partial or total knee replacement were performed. Their mean age at surgery was 63±6,85 years and mean BMI 29,55±5,00 kg/m2. In 238 patients UKA, in 125 TKA, in 21 PFA and in 11 patients BKA was performed. Implants were cemented and made of cobalt chrome in partial knee and zirconium oxide in total knee replacement. Demographics and patient reported outcomes (VAS, KOOS, Oxford Knee Score (OKS)) were collected preoperatively and 3,6 and 12 months postoperatively. A total of 202 patients have thus far completed the 12 months follow-up time point. Results: All mean KOOS and OKS scores improved significantly 1 year after surgery (p<0.05). Mean preoperative aggregated KOOS improved from 49,0±14,1 to 74,3±17,8 in UKA, from 44,1±12,9 to 67,5±9,4 in PFA, from 46,1±15,1 to 71,0±14,8 in TKA and from 45,7±13,8 to 72,6±9,7 in BKA (p<0.05). Mean preoperative aggregated OKS improved from 25,1±7,6) to 38,5±9,7 in UKA, from 23,0±7,6 to 36,8±3,8 in PFA, from 23,4±8,2 to 37,3±8,1 in TKA and from 22,9±9,6 to 37,0±1,5 in BKA (p<0.05). The mean pain level (VAS)decreased from pre-treatment to 12 months after surgery in UKA from 5,5 to 1,6, in PFA from 6,1 to 2,5, in TKA from 6,0 to 1,9 and in BKA from 6,6 to 2,6. One patient (0.4%) underwent revision (at 3 month for inlay dislocation). Conclusion: This study shows excellent early clinical results of patients treated with unicompartmental, bicompartmental and total knee arthroplasty. Adherence to strict indications lead to a significant improvement of patient reported outcomes and a low revision rate one year postoperatively. The reported results for BKA are comparable to those of patients treated with unicompartmental arthroplasty. We conclude that bicompartmental arthroplasty is a safe and reliable surgery for patients with bicompartmental osteoarthritis.

Introduction and Historical Overview

Osteoarthritis of the knee is one of the most common causes of painful loss of mobility in middle-aged and elderly people in many populations and is the main indication for knee replacement surgery. From the early days of arthroplasty, it was recognised that arthritis was often limited to the medial (or lateral) compartment of the knee and, in the pioneering operation of MacIntosh 1 , metal spacers could be used in one compartment or both. Gradually, however, as the advantages of bicompartmental arthroplasty were appreciated, unicompartmental (or partial) replacement was less and less practised, and in some countries almost disappeared. With the introduction of tricompartmental replacement, a large body of surgical opinion concluded that osteoarthritis of the knee was a disease of the whole joint (like osteoarthritis of the hip) and that common sense required the replacement of all the articular surfaces to provide long-term relief of symptoms.