Saker Khamaisy

Unicompartmental knee arthroplasty versus total knee arthroplasty: Which type of artificial joint do patients forget?

AbstractPurposeDuring recent years, there has been an intensive growth of interest in the patient’s perception of functional outcome. The Forgotten Joint Score (FJS) is a recently introduced score that measures joint awareness of patients who have undergone knee arthroplasty and is less limited by ceiling effects. The aim of this study was to compare the FJS between patients who undergo medial unicompartmental knee arthroplasty (UKA) and patients who undergo total knee arthroplasty (TKA) 1 and 2xa0years post-operatively.MethodsThis prospective study compares the FJS at a minimum of one (average 1.5xa0years, range 1.0–1.9) and a minimum of 2xa0years (average 2.5xa0years, range 2.0–3.6) post-operatively between patients who underwent medial UKA and TKA.nResultsOne-hundred and thirty patients were included. Sixty-five patients underwent medial UKA and 65 patients underwent TKA. At both follow-up points, the FJS was significantly higher in the UKA group (FJS 1xa0year 73.9xa0±xa022.8, FJS 2xa0year 74.3xa0±xa024.8) in contrast to the TKA group (FJS 1xa0year 59.3xa0±xa029.5 (pxa0=xa00.002), FJS 2xa0year 59.8xa0±xa031.5, (pxa0=xa00.004)). No significant improvement in the FJS nwas observed between 1- and 2-year follow-up of the two cohorts.ConclusionPatients who undergo UKA are more likely to forget their artificial joint in daily life and consequently may be more satisfied.Level of evidenceII.

Is Tibiofemoral Subluxation Correctable in Unicompartmental Knee Arthroplasty

The purposes of this study were to describe a method for measuring tibiofemoral subluxation in UKA, and to report the mean amount of tibiofemoral subluxation seen both preoperatively and postoperatively in a cohort of patients undergoing UKA. Two hundred thirty-five patients who received a medial UKA, and 39 patients who received a lateral UKA, were reviewed. In the medial UKA cohort, the mechanical alignment was corrected from 7.7° ± 5.9° preoperatively, to 2.9° ± 2.5° postoperatively, while the tibiofemoral subluxation was corrected from 4.5 mm ± 3.0 mm preoperatively, to 2.3 mm ± 2.7 mm postoperatively. In the lateral UKA cohort, the mechanical alignment was corrected from -5.5° ± 3.8° to -1.6° ± 3.4°, while the tibiofemoral subluxation was corrected from 4.3 mm ± 2.7 mm to 2.8 mm ± 2.5mm. This study presents a novel method for measurement of tibiofemoral subluxation, the mean amount of tibiofemoral subluxation present preoperatively, and the amount of correction that can be expected during both medial and lateral unicondylar knee arthroplasty.

Predictors of Subjective Outcome After Medial Unicompartmental Knee Arthroplasty

BACKGROUNDnUnexplainable pain after medial unicompartmental knee arthroplasty (UKA) remains a leading cause for revision surgery. Therefore, the aim of this study is to identify the patient-specific variables that may influence subjective outcomes after medial UKA to optimize results.nnnMETHODSnRetrospectively, we analyzed 104 consecutive medial UKA patients. The evaluated parameters consisted of age, body mass index, gender, preoperative radiographic severity of the various knee compartments, and preoperative and postoperative mechanical axis alignments.nnnRESULTSnAt an average of 2.3-year follow-up, our data demonstrate that body mass index, gender, and preoperative severity among the various knee compartments do not influence Western Ontario and McMaster Universities Arthritis Index (WOMAC) results. Preoperatively, patients aged <65 years had inferior WOMAC stiffness (4.6 vs 2.9, Pxa0= .001), pain (9.7 vs 7.6, Pxa0= .041), and total (37.2 vs 47.6, Pxa0= .028) scores vs patients aged ≥65 years. Postoperatively, only the difference on the WOMAC stiffness subscale remained significant between both age groups, in favor of patients aged ≥65 years (1.0 vs 1.5, Pxa0= .035). A postoperative varus mechanical axis alignment of 1°-4° correlated to significantly superior WOMAC pain (Pxa0= .03), function (Pxa0= .04), and total (Pxa0= .04) scores compared to a varus of ≤1° or ≥4°.nnnCONCLUSIONnOur data suggest that greater pain relief can be expected in patients aged <65 years and that a postoperative lower limb alignment of 1°-4° varus should be pursued. Taking these factors into consideration will help to maximize clinical outcomes, fulfill patient expectations after medial UKA, and subsequently minimize revision rates.

Medial unicompartmental knee arthroplasty improves congruence and restores joint space width of the lateral compartment

BACKGROUNDnOsteoarthritic progression of the lateral compartment remains a leading indication for medial unicompartmental knee arthroplasty (UKA) revision. Therefore, the purpose of this study was to evaluate the alterations of the lateral compartment congruence and joint space width (JSW) following medial UKA.nnnMETHODSnRetrospectively, lateral compartment congruence and JSW were evaluated in 174 knees (74 females, 85 males, mean age 65.5years; SD±10.1) preoperatively and six weeks postoperatively, and compared to 41 healthy knees (26 men, 15 women, mean age 33.7years; SD±6.4). Congruence (CI) was calculated using validated software that evaluates the geometric relationship between surfaces and calculates a congruence index (CI). JSW was measured on three sides (inner, middle, outer) by subdividing the lateral compartment into four quarters.nnnRESULTSnThe CI of the control group was 0.98 (SD±0.01). The preoperative CI was 0.88 (SD±0.01), which improved significantly to 0.93 (SD±0.03) postoperatively (p<0.001). In 82% of knees, CI improved after surgery, while in 18% it decreased. The preoperative significant JSW differences of the inner (p<0.001) and outer JSW (p<0.001) were absent postoperatively.nnnCONCLUSIONnOur data suggests that a well-conducted medial UKA not only resurfaces the medial compartment but also improves congruence and restores the JSW of the lateral compartment.

Coronal tibiofemoral subluxation in knee osteoarthritis

ObjectiveTo analyze knees in varying stages of osteoarthritis (OA) for the presence of coronal tibiofemoral (CTF) subluxation and to determine if CTF subluxation severity is related to knee OA worsening.MethodsWe retrospectively evaluated CTF subluxation and limb alignment in 113 patients with different stages of knee OA who were being considered for an arthroplasty procedure. Knee OA was classified as “mild” or “severe” according to Kellgren-Lawrence scale. CTF subluxation was measured in the study groups and in 40 knees of healthy controls using software developed specifically on the basis of Iterative Closest Point mathematical algorithm.ResultsMean CTF subluxation in “mild OA” and “severe OA” groups was 3.5xa0% (±2) and 3.5xa0% (±5) of the tibial plateau, respectively. For both the mild and severe OA groups, CTF subluxation was significantly increased compared to the 1.4xa0% (±1) CTF subluxation in the control group, (pu2009<u20090.0001) and (pu2009=u20090.012), respectively. However, there was no significant difference in CTF subluxation between the mild OA and severe OA groups (pu2009=u20090.75). Limb varus malalignment in mild OA and severe OA groups was 3.6° (±2.2) and 5.3° (±2.6), respectively. Both significantly increased comparing to the 1° (±0.7) control group alignment (pu2009<u20090.0001). Varus malalignment in the severe OA group was significantly increased comparing to the mild OA group (pu2009=u20090.0003).ConclusionsCTF subluxation is a radiographic finding related to knee OA which occurs mainly in the early stages of the osteoarthritic process and stagnates as OA progresses.

Role of magnetic resonance imaging in the diagnosis of the painful unicompartmental knee arthroplasty

BACKGROUNDnUnicompartmental knee arthroplasty (UKA) is a well established method for the treatment of single compartment arthritis; however, a subset of patients still present with continued pain after their procedure in the setting of a normal radiographic examination. This study investigates the effectiveness of magnetic resonance imaging (MRI) in guiding the diagnosis of the painful unicompartmental knee arthroplasty.nnnMETHODSnAn IRB-approved retrospective review identified 300 consecutive UKAs performed over a three years period with 28 cases of symptomatic UKA (nine percent) with normal radiographic images.nnnRESULTSnMRI examination was instrumental in finding a diagnosis that went undetected on radiographs. Based on MRI findings, 10 (36%) patients underwent surgery whilst 18 (64%) were treated conservatively.nnnCONCLUSIONnThis study supports the use of MRI as a valuable imaging modality for managing symptomatic unicompartmental knee arthroplasty.nnnLEVEL OF EVIDENCEnCase series.

Notchplasty in anterior cruciate ligament reconstruction in the setting of passive anterior tibial subluxation

PURPOSEnIn an effort to minimize graft impingement among various ACL deficient states, we sought to quantitatively determine requirements for bone resection during notchplasty with respect to both volumetric amount and location.nnnMETHODSnA validated method was used to evaluate Magnetic Resonance Imaging scans. We measured the ATT of the medial and lateral compartments in the following four states: intact ACL (27 patients), acute ACL disruption; <2 months post-injury (76 patients), chronic ACL disruption; 12 months post-injury (42 patients) and failed ACL reconstruction (75 patients). Subsequently, 11 cadaveric knees underwent Computed Tomography (CT) scanning. Specialized software allowed virtual anterior translation of the tibia according to the average ATT measured on MRI. Impingement volume was analyzed by performing virtual ACLRs onto the various associated CT scans. Location was analyzed by overlaying an on-screen protractor. The center of the notch was defined as 0°.nnnRESULTSnAverage impingement volume changed significantly in the various groups compared to the intact ACL group (acute 577 ± 200 mm(3), chronic 615 ± 199 mm(3), failed ACLR 678 ± 210 mm(3), p=0.0001). The location of the required notchplasty of the distal femoral wall border did not change significantly. The proximal femoral border moved significantly towards the center of the notch (acute 8.6° ± 4.8°, chronic 7.8° ± 4.2° (p=0.013), failed ACLR 5.1° ± 5.9° (p=0.002)).nnnCONCLUSIONnOur data suggests that attention should be paid peri-operatively to the required volume and location of notchplasty among the various ACL deficient states to minimize graft impingement.

Medial Unicondylar Knee Arthroplasty Improves Patellofemoral Congruence: a Possible Mechanistic Explanation for Poor Association Between Patellofemoral Degeneration and Clinical Outcome

The purpose was to determine the effect of medial fixed bearing unicondylar knee arthroplasty (UKA) on postoperative patellofemoral joint (PFJ) congruence and analyze the relationship of preoperative PFJ degeneration on clinical outcome. We retrospectively reviewed 110 patients (113 knees) who underwent medial UKA. Radiographs were evaluated to ascertain PFJ degenerative changes and congruence. Clinical outcomes were assessed preoperatively and postoperatively. The postoperative absolute patellar congruence angle (10.05 ± 10.28) was significantly improved compared with the preoperative value (14.23 ± 11.22) (P = 0.0038). No correlation was found between preoperative PFJ congruence or degeneration severity, and WOMAC scores at two-year follow up. Pre-operative PFJ congruence and degenerative changes do not affect UKA clinical outcomes. This finding may be explained by the post-op PFJ congruence improvement.

Onlay Tibial Implants Appear to Provide Superior Clinical Results in Robotic Unicompartmental Knee Arthroplasty

BackgroundUnicompartmental knee arthroplasty (UKA) is an increasingly popular option for the treatment of single-compartment knee osteoarthritis (OA) in adults. Two options for tibial resurfacing during UKA are (1) all-polyethylene inlays and (2) metal-backed onlays.Questions/PurposesThe aim of this study was to determine whether there are any differences in clinical outcomes with inlay versus onlay tibial components.Patients and MethodsWe identified 39 inlays and 45 onlays, with average 2.7- and 2.3-year follow-up, respectively, from a prospective robotic-assisted surgery database. The primary outcome was the Western Ontario and McMaster University Arthritis Index (WOMAC), subcategorized by the pain, stiffness, and function subscores, at 2xa0years postoperatively. The secondary outcome was the need for secondary or revision surgery.ResultsPostoperative WOMAC pain score was 3.1 for inlays and 1.6 for onlays (pu2009=u20090.03). For 25 inlays and 30 onlays with both preoperative and postoperative WOMAC data, pain score improved from 8.3 to 4.0 for inlays versus from 9.2 to 1.7 for onlays (pu2009=u20090.01). Function score improved from 27.5 to 12.5 for inlays versus from 32.1 to 7.3 for onlays (pu2009=u20090.03). Four inlays and one onlay required a secondary or revision procedure (pu2009=u20090.18).ConclusionsWe advise using metal-backed onlays during UKA to improve postoperative clinical outcomes.

Congruence and joint space width alterations of the medial compartment following lateral unicompartmental knee arthroplasty

Progressive degenerative changes in the medial compartment of the knee following lateral unicompartmental arthroplasty (UKA) remains a leading indication for revision surgery. The purpose of this study is to evaluate changes in the congruence and joint space width (JSW) of the medial compartment following lateral UKA. The congruence of the medial compartment of 53 knees (24 men, 23 women, mean age 13.1 years; sd 62.1) following lateral UKA was evaluated pre-operatively and six weeks post-operatively, and compared with 41 normal knees (26 men, 15 women, mean age 33.7 years; sd 6.4), using an Interactive closest point algorithm which calculated the congruence index (CI) by performing a rigid transformation that best aligns the digitised tibial and femoral surfaces. Inner, middle and outer JSWs were measured by sub-dividing the medial compartment into four quarters on pre- and post-operative, weight bearing tunnel view radiographs. The mean CI of knees following lateral UKA significantly improved from 0.92 (sd 0.06) pre-operatively to 0.96 (sd 0.02) (p < 0.001) six weeks post-operatively. The mean CI of the healthy control group was 0.99 sd 0.01. Post-operatively, the mean inner JSW increased (p = 0.006) and the outer decreased (p = 0.002). The JSW was restored post-operatively as no significant differences were noted in all three locations compared with the control group (inner JSW p = 0.43; middle JSW p = 0.019, outer JSW p = 0.51). Our data suggest that a well conducted lateral UKA may improve the congruence and normalise the JSW of the medial compartment, potentially preventing progression of degenerative change.