Aims. Manipulation under anaesthesia (MUA) remains an effective intervention to address restricted range of motion (ROM) after total knee arthroplasty (TKA) and occurs in 2% to 3% of primary TKAs at our institution. Since there are few data on the outcomes of MUA with different anaesthetic methods, we sought to compare the outcomes of patients undergoing MUA with intravenous (IV) sedation and neuraxial anaesthesia. Methods. We identified 548 MUAs after primary TKA (136 IV sedation, 412 neuraxial anaesthesia plus IV sedation) from March 2016 to July 2019. The mean age of this cohort was 62 years (35 to 88) with a mean body mass index of 31 kg/m. 2. (18 to 49). The mean time from primary TKA to MUA was 10.2 weeks (6.2 to 24.3). Pre-MUA ROM was similar between groups; overall mean pre-MUA extension was 4.2° (p = 0.452) and mean pre-MUA flexion was 77° (p = 0.372). We compared orthopaedic complications, visual analogue scale (VAS) pain scores, length of stay (LOS), and immediate and three-month follow-up knee ROM between these groups. Results. Following MUA, patients with IV sedation had higher mean VAS pain scores of 5.2 (SD 1.8) compared to 4.1 (SD = 1.5) in the neuraxial group (p < 0.001). The mean LOS was shorter in patients that received IV sedation (9.5 hours (4 to 31)) compared to neuraxial anaesthesia (11.9 hours (4 to 51)) (p = 0.009), but an unexpected overnight stay was similar in each group (8.6%). Immediate-post MUA ROM was 1° to 121° in the IV sedation group and 0.9° to 123° in the neuraxial group (p = 0.313). Three-month follow-up ROM was 2° to 108° in the IV sedation group and 1.9° to 110° in the neuraxial anaesthesia group (p = 0.325) with a mean loss of 13° (ranging from 5° gain to 60° loss), in both groups by three months. No patients in either group sustained a complication. Conclusion. IV sedation alone and neuraxial anaesthesia are both effective anaesthetic methods for MUA after primary TKA. Surgeons and anaesthetists should offer these anaesthetic techniques to match patient-specific needs as the orthopaedic outcomes are similar. Also, patients should be counselled that ROM following MUA may decrease over time. Cite this article: Bone Joint J 2021;103-B(6 Supple A):126–130

Aims. Postoperative range of movement (ROM) is an important measure of successful and satisfying total knee arthroplasty (TKA). Reduced postoperative ROM may be evident in up to 20% of all TKAs and negatively affects satisfaction. To improve ROM, manipulation under anaesthesia (MUA) may be performed. Historically, a limited ROM preoperatively was used as the key harbinger of the postoperative ROM. However, comorbidities may also be useful in predicting postoperative stiffness. The goal was to assess preoperative comorbidities in patients undergoing TKA relative to incidence of postoperative MUA. The hope is to forecast those who may be at increased risk and determine if MUA is an effective form of treatment. Methods. Prospectively collected data of TKAs performed at our institution’s two hospitals from August 2014 to August 2018 were evaluated for incidence of MUA. Comorbid conditions, risk factors, implant component design and fixation method (cemented vs cementless), and discharge disposition were analyzed. Overall, 3,556 TKAs met the inclusion criteria. Of those, 164 underwent MUA. Results. Patients with increased age and body mass index (BMI) had decreased likelihood of MUA. For every one-year increase in age, the likelihood of MUA decreased by 4%. Similarly, for every one-unit increase in BMI the likelihood of MUA decreased by 6%. There were no differences in incidence of MUA between component type/design or fixation method. Current or former smokers were more likely to have no MUA. Surprisingly, patients discharged to home health service or skilled nursing facility were approximately 40% and 70% less likely than those discharged home with outpatient therapy to be in the MUA group. MUA was effective, with a mean increased ROM of 32.81° (SD 19.85°; -15° to 90°). Conclusion. Younger, thinner patients had highest incidence of MUA. Effect of discharge disposition on rate of MUA was an important finding and may influence surgeons’ decisions. Interestingly, use of cement and component design (constraint) did not impact incidence of MUA. Level of Evidence II: Prospective cohort study. Cite this article: Bone Joint J 2020;102-B(6 Supple A):66–72

Aims. The aim of this study was to compare ten-year longitudinal healthcare costs and revision rates for patients undergoing unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). Methods. The Humana database was used to compare 2,383 patients undergoing UKA between 2007 and 2009, who were matched 1:1 from a cohort of 63,036 patients undergoing primary TKA based on age, sex, and Elixhauser Comorbidity Index. Medical and surgical complications were tracked longitudinally for one year following surgery. Rates of revision surgery and cumulative mean healthcare costs were recorded for this period of time and compared between the cohorts. Results. Patients undergoing TKA had significantly higher rates of manipulation under anaesthesia (3.9% vs 0.9%; p < 0.001), deep vein thrombosis (5.0% vs 3.1%; p < 0.001), pulmonary embolism (1.5% vs 0.8%; p = 0.001), and renal failure (4.2% vs 2.2%; p < 0.001). Revision rates, however, were significantly higher for UKA at five years (6.0% vs 4.2%; p = 0.007) and ten years postoperatively (6.5% vs 4.4%; p = 0.002). Longitudinal-related healthcare costs for patients undergoing TKA were greater than for those undergoing UKA at one year ($24,771 vs $22,071; p < 0.001) and five years following surgery ($26,549 vs $25,730; p < 0.001); however, the mean costs of TKA were comparable to UKA at ten years ($26,877 vs $26,891; p = 0.425). Conclusion. Despite higher revision rates, patients undergoing UKA had lower mean healthcare costs than those undergoing TKA up to ten years following the procedure, at which time costs were comparable. In the era of value-based care, surgeons and policymakers should be aware of the costs involved with these procedures. UKA was associated with fewer complications at one year postoperatively but higher revision rates at five and ten years. While UKA was significantly less costly than TKA at one and five years, costs at ten years were comparable with a mean difference of only $14. Lowering the risk of revision surgery should be targeted as a source of cost savings for both UKA and TKA as the mean related healthcare costs were 2.5-fold higher in patients requiring revision surgery. Cite this article: Bone Joint J 2021;103-B(6 Supple A):23–31

Aims. Alternative alignment concepts, including kinematic and restricted kinematic, have been introduced to help improve clinical outcomes following total knee arthroplasty (TKA). The purpose of this study was to evaluate the clinical results, along with patient satisfaction, following TKA using the concept of restricted kinematic alignment. Methods. A total of 121 consecutive TKAs performed between 11 February 2018 to 11 June 2019 with preoperative varus deformity were reviewed at minimum one-year follow-up. Three knees were excluded due to severe preoperative varus deformity greater than 15°, and a further three due to requiring revision surgery, leaving 109 patients and 115 knees to undergo primary TKA using the concept of restricted kinematic alignment with advanced technology. Patients were stratified into three groups based on the preoperative limb varus deformity: Group A with 1° to 5° varus (43 knees); Group B between 6° and 10° varus (56 knees); and Group C with varus greater than 10° (16 knees). This study group was compared with a matched cohort of 115 TKAs and 115 patients using a neutral mechanical alignment target with manual instruments performed from 24 October 2016 to 14 January 2019. Results. Mean overall patient satisfaction for the entire cohort was 4.7 (SE 0.1) on a 5-point Likert scale, with 93% being either very satisfied or satisfied compared with a Likert of 4.3 and patient satisfaction of 81% in the mechanical alignment group (p < 0.001 and p < 0.006 respectively). At mean follow-up of 17 months (11 to 27), the mean overall Likert, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, and Knee Society Knee and Function Scores were significantly better in the kinematic group than in the neutral mechanical alignment group. The most common complication in both groups was contracture requiring manipulation under anaesthesia, involving seven knees (6.1%) in the kinematic group and nine knees (7.8%) in the mechanical alignment group. Conclusion. With the advent of advanced technology, and the ability to obtain accurate bone cuts, the target limb alignment, and soft-tissue balance within millimetres, using a restricted kinematic alignment concept demonstrated excellent patient satisfaction following primary TKA. Longer-term analysis is required as to the durability of this method. Cite this article: Bone Joint J 2021;103-B(6 Supple A):59–66

Aims. A significant percentage of patients remain dissatisfied after total knee arthroplasty (TKA). The aim of this study was to determine whether the sequential addition of accelerometer-based navigation for femoral component preparation and sensor-guided ligament balancing improved complication rates, radiological alignment, or patient-reported outcomes (PROMs) compared with a historical control group using conventional instrumentation. Methods. This retrospective cohort study included 371 TKAs performed by a single surgeon sequentially. A historical control group, with the use of intramedullary guides for distal femoral resection and surgeon-guided ligament balancing, was compared with a group using accelerometer-based navigation for distal femoral resection and surgeon-guided balancing (group 1), and one using navigated femoral resection and sensor-guided balancing (group 2). Primary outcome measures were Patient-Reported Outcomes Measurement Information System (PROMIS) and Knee injury and Osteoarthritis Outcome (KOOS) scores measured preoperatively and at six weeks and 12 months postoperatively. The position of the components and the mechanical axis of the limb were measured postoperatively. The postoperative range of motion (ROM), haematocrit change, and complications were also recorded. Results. There were 194 patients in the control group, 103 in group 1, and 74 in group 2. There were no significant differences in baseline demographics between the groups. Patients in group 2 had significantly higher baseline mental health subscores than control and group 1 patients (53.2 vs 50.2 vs 50.2, p = 0.041). There were no significant differences in any PROMs at six weeks or 12 months postoperatively (p > 0.05). There was no difference in the rate of manipulation under anaesthesia (MUA), complication rates, postoperative ROM, or blood loss. There were fewer mechanical axis outliers in groups 1 and 2 (25.2%, 14.9% respectively) versus control (28.4%), but this was not statistically significant (p = 0.10). Conclusion. The sequential addition of navigation of the distal femoral cut and sensor-guided ligament balancing did not improve short-term PROMs, radiological outcomes, or complication rates compared with conventional techniques. The costs of these added technologies may not be justified. Cite this article: Bone Joint J 2020;102-B(6 Supple A):24–30

Aims. The purpose is to determine the non-inferiority of a smartphone-based exercise educational care management system after primary knee arthroplasty compared with a traditional in-person physiotherapy rehabilitation model. Methods. A multicentre prospective randomized controlled trial was conducted evaluating the use of a smartphone-based care management system for primary total knee arthroplasty (TKA) and partial knee arthroplasty (PKA). Patients in the control group (n = 244) received the respective institution’s standard of care with formal physiotherapy. The treatment group (n = 208) were provided a smartwatch and smartphone application. Early outcomes assessed included 90-day knee range of movement, EuroQoL five-dimension five-level score, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) score, 30-day single leg stance (SLS) time, Time up and Go (TUG) time, and need for manipulation under anaesthesia (MUA). Results. Overall, 90-day mean flexion was not significantly different between the control (121° (SD 11.7°)) and treatment groups (121. o. ; p = 0.559); 90-day mean SLS was 22.7 seconds (SD 9.8) in controls and 24.3 seconds (SD 20.8) in treatment (p = 0.519); 90-day mean TUG times were 10.1 seconds (SD 4.8) in control and 9.3 seconds (SD 3.3) in treatment (p = 0.139). Mean KOOS JR scores were significantly different between control group (73.6 (SD 13.4)) and treatment group (70.4 (SD 12.6); p = 0.026). MUAs were performed in nine (3.7%) patients in the control group and four (1.9%) in the treatment group (p = 0.398). Physiotherapy was performed by 230 (94.4%) of control group and 123 (59.3%) of treatment group (p < 0.001). There were no significant differences between groups in postoperative urgent care visits, or readmissions within 90 days, with significantly fewer emergency department visits in the treatment group (16 (8.2%) vs five (2.5%), p = 0.014). Conclusion. The use of the smartwatch/smartphone care platform demonstrated non-inferiority of clinically significant outcomes to traditional care models, while requiring significantly less postoperative physiotherapy and fewer emergency department visits. This platform could aid in decreasing postoperative costs, while improving patient engagement and communication with the healthcare team. Cite this article: Bone Joint J 2021;103-B(6 Supple A):3–12

Aims. To compare patients undergoing total knee arthroplasty (TKA) with ≤ 80° range of movement (ROM) operated with a 2 mm increase in the flexion gap with matched non-stiff patients with at least 100° of preoperative ROM and balanced flexion and extension gaps. Methods. In a retrospective cohort study, 98 TKAs (91 patients) with a preoperative ROM of ≤ 80° were examined. Mean follow-up time was 53 months (24 to 112). All TKAs in stiff knees were performed with a 2 mm increased flexion gap. Data were compared to a matched control group of 98 TKAs (86 patients) with a mean follow-up of 43 months (24 to 89). Knees in the control group had a preoperative ROM of at least 100° and balanced flexion and extension gaps. In all stiff and non-stiff knees posterior stabilized (PS) TKAs with patellar resurfacing in combination with adequate soft tissue balancing were used. Results. Overall mean ROM in stiff knees increased preoperatively from 67° (0° to 80°) to 114° postoperatively (65° to 135°) (p < 0.001). Mean knee flexion improved from 82° (0° to 110°) to 115° (65° to 135°) and mean flexion contracture decreased from 14° (0° to 50°) to 1° (0° to 10°) (p < 0.001). The mean Knee Society Score (KSS) improved from 34 (0 to 71) to 88 (38 to 100) (p < 0.001) and the KSS Functional Score from 43 (0 to 70) to 86 (0 to 100). Seven knees (7%) required manipulations under anaesthesia (MUA) and none of the knees had flexion instability. The mean overall ROM in the control group improved from 117° (100° to 140°) to 123° (100° to 130°) (p < 0.001). Mean knee flexion improved from 119° (100° to 140°) to 123° (100° to 130°) (p < 0.001) and mean flexion contracture decreased from 2° (0° to 15°) to 0° (0° to 5°) (p < 0.001). None of the knees in the control group had flexion instability or required MUA. The mean KSS Knee Score improved from 48 (0 to 80) to 94 (79 to 100) (p < 0.001) and the KSS Functional Score from 52 (5 to 100) to 95 (60 to 100) (p < 0.001). Mean improvement in ROM (p < 0.001) and KSS Knee Score (p = 0.017) were greater in knees with preoperative stiffness compared with the control group, but the KSS Functional Score improvement was comparable (p = 0.885). Conclusion. TKA with a 2 mm increased flexion gap provided a significant improvement of ROM in knees with preoperative stiffness. While the improvement in ROM was greater, the absolute postoperative ROM was less than in matched non-stiff knees. PS TKA with patellar resurfacing and a 2 mm increased flexion gap, in combination with adequate soft tissue balancing, provides excellent ROM and knee function when stiffness of the knee had been present preoperatively. Cite this article: Bone Joint J 2020;102-B(4):426–433

Aims. Knee osteonecrosis in advanced stages may lead to joint degeneration. Total knee arthroplasty (TKA) for osteonecrosis has traditionally been associated with suboptimal results. We analyzed outcomes of contemporary TKAs for osteonecrosis, with particular emphasis on: survivorship free from aseptic loosening, any revision, and any reoperation plus the clinical outcomes, complications, and radiological results. Patients and Methods. In total, 156 patients undergoing 167 primary TKAs performed for osteonecrosis between 2004 and 2014 at a single institution were reviewed. The mean age at index TKA was 61 years (14 to 93) and the mean body mass index (BMI) was 30 kg/m. 2. (18 to 51) The mean follow-up was six years (2 to 12). A total of 110 TKAs (66%) were performed for primary osteonecrosis and 57 TKAs (34%) for secondary osteonecrosis. Overall, 15 TKAs (9%) had tibial stems, while 12 TKAs (7%) had femoral stems. Posterior-stabilized designs were used in 147 TKAs (88%) of TKAs. Bivariate Cox regression analysis was conducted to identify risk factors for revision and reoperation. Results. Survivorship free from aseptic loosening, any revision, and any reoperation at ten years was 97% (95% confidence interval (CI) 93 to 100), 93% (95% CI 85 to 100), and 82% (95% CI 69 to 93), respectively. No factors, including age, sex, BMI, primary versus secondary osteonecrosis, stem utilization, and constraint, were identified as risk factors for reoperation. Four TKAs (2%) underwent revision, most commonly for tibial aseptic loosening (n = 2). Excluding revisions and reoperations, there was a total of 11 complications (7%), with the most common being a manipulation under anaesthesia (six TKAs, 4%). Mean Knee Society Scores (Knee component) significantly improved from 57 (32 to 87) preoperatively to 91 (49 to 100) postoperatively (p < 0.001). No unrevised TKAs had complete radiolucent lines or radiological evidence of loosening. Conclusion. Contemporary cemented TKAs with selective stem utilization for osteonecrosis resulted in durable survivorship, a low complication rate, and reliable improvement in clinical outcomes. Cite this article: Bone Joint J 2019;101-B:1356–1361

Aims. Between 15% and 20% of patients remain dissatisfied following total knee arthroplasty (TKA). The SAIPH knee system (MatOrtho, Surrey, United Kingdom) is a medial ball and socket TKA that has been designed to replicate native knee kinematics in order to maximize the range of movement, stability, and function. This system is being progressively introduced in a stepwise fashion, with this study reporting the mid-term clinical and radiological outcomes. Patients and Methods. A retrospective review was undertaken of the first 100 consecutive patients with five-year follow-up following SAIPH TKA performed by the senior authors. The data that were collected included the demographics of the patients, clinical findings, the rate of intraoperative ligamentous release, patient-reported outcome measures (PROMS), radiological assessment, complications, and all-cause revision. Revision data were cross-checked with a national registry. Results. A total of 100 TKAs in 92 patients were included. Three patients died (three TKAs) and a further two TKAs were revised. Of the remaining 95 TKAs, five-year follow-up data were available for 81 TKAs (85%) in 87 patients. There were significant improvements in all PROMs and high satisfaction. The mean ROM at final follow-up was from 0° (full extension) to 124° flexion. There were seven major complications (7%): one infection, two deep vein thromboses, one cerebrovascular event, and two patients with stiffness requiring a manipulation under anaesthesia. Two patients required a lateral retinacular release to optimize patellar tracking in valgus knees; no additional ligament releases were performed in any patient. Radiological analysis demonstrated no evidence of implant-related complications. Conclusion. These results demonstrate satisfactory clinical and radiological outcomes at five years following a medial ball and socket TKA. The complication and revision rates are consistent with those previously reported for patients undergoing TKA. These results demonstrate the safety and efficacy of the SAIPH Knee TKA system and support its wider use

Aims. Since redesign of the Oxford phase III mobile-bearing unicompartmental knee arthroplasty (UKA) femoral component to a twin-peg design, there has not been a direct comparison to total knee arthroplasty (TKA). Thus, we explored differences between the two cohorts. Patients and Methods . A total of 168 patients (201 knees) underwent medial UKA with the Oxford Partial Knee Twin-Peg. These patients were compared with a randomly selected group of 177 patients (189 knees) with primary Vanguard TKA. Patient demographics, Knee Society (KS) scores and range of movement (ROM) were compared between the two cohorts. Additionally, revision, re-operation and manipulation under anaesthesia rates were analysed. Results. The mean follow-up for UKA and TKA groups was 5.4 and 5.5 years, respectively. Six TKA (3.2%) versus three UKAs (1.5%) were revised which was not significant (p = 0.269). Manipulation was more frequent after TKA (16; 8.5%) versus none in the UKA group (p <  0.001). UKA patients had higher post-operative KS function scores versus TKA patients (78 versus 66, p < 0.001) with a trend toward greater improvement, but there was no difference in ROM and KS clinical improvement (p = 0.382 and 0.420, respectively). Conclusion. We found fewer manipulations, and higher functional outcomes for patients treated with medial mobile-bearing UKA compared with TKA. TKA had twice the revision rate as UKA although this did not reach statistical significance with the numbers available. . Cite this article: Bone Joint J 2016;98-B(10 Suppl B):28–33

This prospective study describes the complications and survival of the first 688 Phase 3 Oxford medial unicompartmental knee replacements implanted using a minimally-invasive technique by two surgeons and followed up independently. None was lost to follow-up. We had carried out 132 of the procedures more than five years ago. The clinical assessment of 101 of these which were available for review at five years is also presented. Nine of the 688 knees were revised: four for infection, three for dislocation of the bearing and two for unexplained pain. A further seven knees (1%) required other procedures: four had a manipulation under anaesthesia, two an arthroscopy and one a debridement for superficial infection. The survival rate at seven years was 97.3% (95% confidence interval 5.3). At five years, 96% of the patients had a good or excellent American Knee Society score, the mean Oxford knee score was 39 and the mean flexion was 133°. This study demonstrates that the minimally-invasive Oxford unicompartmental knee replacement is a reliable and effective procedure

As part of a prospective study of 476 total knee replacements (TKR), we evaluated the use of manipulation under anaesthesia in 47 knees. Manipulation was considered when intensive physiotherapy failed to increase flexion to more than 80°. The mean time from arthroplasty to manipulation was 11.3 weeks (median 9, range 2 to 41). The mean active flexion before manipulation was 62° (35 to 80). One year later the mean gain was 33° (Wilcoxon signed-rank test, range −5 to 70, 95% CI 28.5 to 38.5). Definite sustained gains in flexion were achieved even when manipulation was performed four or more months after arthroplasty (paired t-test, p < 0.01, CI 8.4 to 31.4). A further 21 patients who met our criteria for manipulation declined the procedure. Despite continued physiotherapy, there was no significant increase in flexion in their knees. Six weeks to one year after TKR, the mean change was 3.1° (paired t-test, p = 0.23, CI −8.1 to +2)

Seven stiff total knee arthroplasties are presented to illustrate the roles of: 1) manipulation under general anesthesia; 2) multiple concurrent diagnoses in addition to stiffness; 3) extra-articular pathology; 4) pain as part of the stiffness triad (pain and limits to flexion or extension); 5) component internal rotation; 6) multifactorial etiology; and 7) surgical exposure in this challenging clinical problem

Aims

Tibial tubercle osteotomy (TTO) facilitates surgical exposure and protects the extensor mechanism during revision total knee arthroplasty (rTKA). The purpose of this study was to determine the rates of bony union, complications, and reoperations following TTO during rTKA, to assess the functional outcomes of rTKA with TTO at two years’ minimum follow-up, and to identify the risk factors of failure.

Aims

Total knee arthroplasty (TKA) with a highly congruent condylar-stabilized (CS) articulation may be advantageous due to increased stability versus cruciate-retaining (CR) designs, while mitigating the limitations of a posterior-stabilized construct. The aim was to assess ten-year implant survival and functional outcomes of a cemented single-radius TKA with a CS insert, performed without posterior cruciate ligament sacrifice.

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Intraoperative pressure sensors allow surgeons to quantify soft-tissue balance during total knee arthroplasty (TKA). The aim of this study was to determine whether using sensors to achieve soft-tissue balance was more effective than manual balancing in improving outcomes in TKA.

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The use of cementless total knee arthroplasty (TKA) components has increased during the past decade. The initial design of cementless metal-backed patellar components had shown high failure rates due to many factors. The aim of this study was to evaluate the clinical results of a second-generation cementless, metal-backed patellar component of a modern design.

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Knowledge on total knee arthroplasties (TKAs) in patients with a history of poliomyelitis is limited. This study compared implant survivorship and clinical outcomes among affected and unaffected limbs in patients with sequelae of poliomyelitis undergoing TKAs.

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Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m²). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m² to examine whether this is supported.

Aims

This study compared patient-reported outcomes of three total knee arthroplasty (TKA) designs from one manufacturer: one cruciate-retaining (CR) design, and two cruciate-sacrificing designs, anterior-stabilized (AS) and posterior-stabilized (PS).