Early and Delayed Meniscal Shrinkage After Fresh-Frozen Lateral Meniscal Allograft Transplantation: Magnetic Resonance Imaging Study With a Midterm Follow-up.

PURPOSE: To evaluate whether fresh-frozen meniscal allograft shrinkage occurs only during the first year of the early remodeling period or progresses over the delayed period of midterm years and to determine whether these changes were associated with certain clinical and radiologic outcomes. METHODS: We retrospectively reviewed meniscal allograft transplantations (MATs) performed by 1 senior surgeon (S-I.B.) using fresh-frozen allograft from 2008 to 2013. The inclusion criteria were the patients who had midterm follow-up magnetic resonance imaging (MRI) scans between 3 and 6 years after isolated lateral MATs. We excluded the graft tears found on the 1-year or midterm MRI scans. MATs were indicated for the treatment persistent compartmental pain in young to middle-aged, physically active patients who had well-aligned nonarthritic joint without ligament insufficiency. The meniscal width of the transplants at the midbody and posterior horn was measured on day 2 (as a reference), at 1 year (after early remodeling period), and after 3 to 6 years (delayed period) postoperatively. Joint space width changes during each interval were measured on 45° flexion posteroanterior views. The Lysholm score and Tegner activity scale were used to evaluate clinical outcomes. RESULTS: Eighty-four isolated lateral MATs with the midterm MRI scans were identified. Of these, 17 graft tears were found; therefore, we analyzed 67 patients (32 male and 35 female patients) with a mean age of 30.9 years (range, 15-52 years). The mean relative meniscal width at the midbody decreased to 93.7% (95% confidence interval [CI], 91.8%-95.6%; P < .001) at 1 year postoperatively and to 88.0% (95% CI, 85.6%-90.3%; P < .001) at the midterm follow-up of 4.0 ± 1.0 years. The posterior horn shrank less than the midbody during the same period (96.0%; 95% CI, 94.8%-97.1%) at 1 year (P < .001) and 92.5% (95% CI, 91.0%-94.1%) at the last follow-up (P < .001). Although there was no severe shrinkage (>50% of the initial size), the incidence of moderate (25%-50%) changes at the midbody increased from 1 (1.5%) at 1 year to 5 (7.5%) at the last follow-up, respectively. We could not find any significant positive correlations between the relative meniscal width and patient-reported outcomes or joint space width changes after 1 year or at the last follow-up. CONCLUSIONS: Shrinkage of fresh-frozen meniscal transplants occurred during both the early remodeling and delayed midterm periods. Although the changes were greater in the midbody than in the posterior horn, the overall changes were less than those of the previous studies using cryopreserved grafts. We could not find that the meniscal shrinkage over the midterm period were significantly associated with inferior outcomes in this series. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Total Knee Arthroplasty With Patellar Retention: The Severity of Patellofemoral Osteoarthritis Did Not Affect the Clinical and Radiographic Outcomes.

BACKGROUND: The purpose of this study is to compare the clinical and radiographic outcomes of total knee arthroplasty (TKA) with patellar retention in accordance with the severity of patellofemoral arthritis. METHODS: We retrospectively reviewed patients who underwent TKA with patellar retention using the NexGen LPS or LPS-flex system between September 2010 and May 2015. The radiographic severity of patellofemoral arthritis was categorized according to the Iwano classification system, and subjects were divided into mild (stage 0-I) and moderate to severe (stage II-IV) groups. Clinical outcomes were evaluated using the Hospital for Special Surgery score, Knee Society Score, function score, Western Ontario and McMaster Universities Osteoarthritis Index, and Feller score. Radiographic outcomes were assessed using the congruence angle, patellar tilt angle, and lateral patellar displacement. The minimum follow-up for clinical and radiographic evaluation was 2 years. Clinical and radiographic outcomes were compared between the 2 groups preoperatively and at the time of the last follow-up. RESULTS: Four hundred seventy-four knees were enrolled and assigned to mild (n = 208) or moderate to severe (n = 266) groups. The preoperative Feller score was significantly lower in the moderate to severe group (P = .030), whereas the postoperative clinical and radiographic results did not differ significantly between the 2 groups. CONCLUSION: Clinical and radiographic outcomes did not differ in accordance with the severity of patellofemoral arthritis after a minimum 2 years of follow-up of patients treated with TKA with patellar retention. Good outcomes were obtained with patellar retention in TKA, even in patients with advanced patellofemoral osteoarthritis.

Using a Tibial Short Extension Stem Reduces Tibial Component Loosening After Primary Total Knee Arthroplasty in Severely Varus Knees: Long-term Survival Analysis With Propensity Score Matching.

BACKGROUND: Patients with severe preoperative varus deformity have been reported to have high rates of loosening after total knee arthroplasty (TKA), primarily on the tibial side. This study investigated whether a short extension stem for the tibial component in severely varus knees would reduce the failure rate due to loosening on the tibial side. METHODS: Patients who underwent TKA, performed by a single surgeon using a single implant between November 1998 and January 2009, were retrospectively evaluated. Patients diagnosed with primary osteoarthritis, having a hip-knee-ankle axis greater than varus 8° on preoperative long-film radiographs, and postoperatively followed up for more than 2 years were included. Patients were divided into "stem" and "nonstem" groups, followed by 1:1 propensity score matching according to age, gender, body mass index, preoperative mechanical axis, and postoperative alignment. Tibial loosening rates in the 2 groups were compared. RESULTS: The study cohort included 602 patients, divided into "stem" and "nonstem" groups. Propensity score matching yielded 88 pairs of patients. Mean follow-up duration was similar in the stem and nonstem groups (109.22 vs 103.81 months, P = .451). None of the patients in the stem group, compared with 5 in the nonstem group, experienced aseptic loosening. The overall implant survival rate was significantly higher in the stem group than in the nonstem group (P = .0201). CONCLUSION: Using a short extension stem for the tibial component in primary TKA in patients with severe varus deformity greater than 8° may reduce the rate of loosening of the tibial side and increase the longevity of the implant. LEVEL OF EVIDENCE: Level III.

Analysis of stored and transplanted cord blood units from KoreaCORD: reappraisal of banking guidelines and selection strategy.

BACKGROUND: We analyzed the characteristics of stored and transplanted cord blood (CB) units from the Korean network for public CB donation (KoreaCORD) to reassess the banking guidelines and optimize CB selection based on cell dose and human leukocyte antigen (HLA) mismatching. STUDY DESIGN AND METHODS: We retrospectively reviewed data, with regard to total nucleated cell (TNC) count and HLA match in the KoreaCORD registry from August 2001 to December 2010. RESULTS: A total of 21,914 CB units have been registered, of which 904 units (4.1%) contained less than 5 × 10(8) TNCs, which did not meet the present storage criteria for public CB banking in Korea. Although the proportion of stored CBs providing TNC of 5 × 10(8) to 7.9 × 10(8) was 45.7%, only 22.0% of all transplanted CBs were derived from these stored CBs. In the single CB transplantation setting, 79% (85/108) of CB units provided 4 × 10(7) TNCs/kg or more in the transplanted one-mismatch (1-MM) CB units and 51% (19/37) of CBs provided 6 × 10(7) TNCs/kg or more in the transplanted 2-MM CB units. CONCLUSIONS: The minimal requirement of TNCs for banking of CB units for public banking should be evaluated and increased to support the selection of CB units with higher cell doses, especially for use in the 1- and 2-MM transplant settings.

Morphologic MRI changes of the anterior cruciate ligament are associated with an increase in the medial tibial plateau bony slope after medial opening wedge high tibial osteotomy in a non-injured ACL population.

BACKGROUND: Medial opening wedge high tibial osteotomy (OWHTO) is a useful treatment for medial osteoarthritis. However, OWHTO sometimes causes a change in tibial slope in the sagittal plane. Although several studies have described the effects of the tibial slope on the biomechanics of the knee, including the anterior cruciate ligament (ACL), there has been little study of the magnetic resonance imaging (MRI) visible changes occurring to the native ACL and the factors affecting them after OWHTO. HYPOTHESIS: We hypothesized that morphologic MRI changes to an uninjured ACL after OWHTO would be associated with increased medial tibial plateau bony slope. PATIENTS AND METHODS: Thirty-three patients who underwent OWHTO and pre/postoperative MRI were included in this retrospective study. The mean period of follow-up MRI was 22.35 (±14.78) months. The patients were divided into two groups according to the occurrence of postoperative ACL morphologic MRI changes defined as mucoid degeneration, ganglion cyst occurrence, or change in the ACL fiber shape (stationary group n=21, altered group n=12). The medial tibial plateau bony slope (MTS) and anterior tibial translation (ATT) were evaluated on MRI. Logistic regression analysis was used to determine factors affecting the occurrence of postoperative ACL morphologic changes. RESULTS: Postoperative MTS and the difference between pre- and post values (ΔMTS), postoperative ATT and the difference between pre- and post values (ΔATT) were significantly different between stationary and altered groups. ΔMTS was associated with postoperative morphologic changes to the ACL (odds ratio: 0.30, 95% confidence interval=0.11-0.82, p=0.019). CONCLUSION: The occurrence of morphologic ACL change after OWHTO is associated with the amount of MTS change. LEVEL OF EVIDENCE: III, Retrospective comparative study.

Hinge Fractures Are Underestimated on Plain Radiographs After Open Wedge Proximal Tibial Osteotomy: Evaluation by Computed Tomography.

BACKGROUND: Lateral hinge fracture (LHF) after medial open wedge high tibial osteotomy (MOWHTO) may not be recognized on perioperative plain radiographs. Such cases may be identified at follow-up and misdiagnosed as delayed LHF. PURPOSE: This study aimed to investigate the extent of LHF misdiagnosis and to determine whether patients with LHFs have inferior clinical outcomes after MOWHTO. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Fifty-one knees in 50 patients (36 women, 14 men; mean age, 51.8 years; range, 24-64 years) who had undergone MOWHTO with locking plate fixation between October 2013 and April 2016 were retrospectively reviewed. LHFs identified on intraoperative fluoroscopy and immediate postoperative radiographs were compared with the actual incidence based on computed tomography (CT) scans performed within 2 days of surgery. Delayed LHFs, not visible on the CT scans but found on later follow-up radiographs, were also assessed. More frequent radiographic check-ups were recommended in patients with LHFs, and weightbearing was delayed until evident callus formation was seen on follow-up radiographs for type 2 or 3 fractures. The loss of correction, the time of union, and complication rate were compared between the knees with LHF and those without LHF. Clinical outcome was measured according to the Knee Society (KS) scores. RESULTS: Overall, 14 early LHFs (27.5%) were identified on CT scans. Of these, 7 LHFs (13.7%) were observed on perioperative radiographs, and the remaining 7 LHFs were identified on later radiographs. Delayed LHFs occurred in 2 cases (3.9%). In the 16 knees with LHF, minimal loss of correction was observed 1 month to 1 year postoperatively without statistical significance. No alignment changes were seen in the 35 knees without LHFs. In the LHF versus no LHF groups, no significant differences were seen regarding time of union (5.3 ± 1.7 months vs 5.4 ± 1.8 months, respectively; P = .898) and postoperative KS scores (knee score, 96.6 ± 2.5 vs 95.3 ± 6.4, P = .435; functional score, 94.4 ± 9.6 vs 89.1 ± 10.9, P = .107). No other complications occurred in either group. CONCLUSION: Most LHFs after MOWHTO occurred intraoperatively, but half (7/14) were not identified on postoperative radiographs. CT scans would enable detection of early LHFs that would otherwise have been mistaken for delayed LHF. However, clinical outcomes did not differ between patients with and without LHF.