A 67-year-old Japanese woman underwent OWHTO to treat SPONK that had occurred in the left medial femoral condyle (Fig. ). The patient reported the following history of the present illness. Pain in the left knee joint initially occurred at 1 year and 4 months before admission, without any particular trigger. Her former treating physician had provided conservative treatments such as oral administration of anti-inflammatory analgesics, rehabilitation including quadriceps muscle training, and guidance on the use of a cane to relieve weight bearing. However, this treatment was not successful in relieving her symptoms, and she was referred to our department for surgery. The patient had a history of hypertension and hyperlipidemia, and she had been taking oral candesartan and atorvastatin. The patient was a housewife with no noteworthy aspects related to social, family, or environmental history. On physical examination, the patient had a height of 157 cm, a body weight of 62 kg, and a body mass index of 25.2 kg/m2. She reported feeling pain in the medial joint space of the knee during walking, as well as during climbing or descending stairs. At the time of the first admission, her systolic/diastolic blood pressure was 165/97 mmHg. Table provides an overview of the patient鈥檚 pain scores in the knee joint, ROM of the knee joint, and knee joint function. Neurological examination revealed no abnormal findings. Similarly, laboratory findings at the time of the first admission did not indicate any abnormality: total protein 7.3 g/dl, albumin 4.6 g/dl, aspartate aminotransferase 22 U/L, alanine aminotransferase 18 U/L, lactate dehydrogenase 213 U/L, alkaline phosphatase 297 U/L, 纬-glutamyl transferase 18 U/L, total bilirubin 0.6 mg/dl, Na 142 mEq/L, Cl 104 mEq/L, K 4.5 mEq/L, blood urea nitrogen 21.4 mg/dl, creatinine 0.56 mg/dl, Ca 9.7 mg/dl, inorganic phosphorus 3.7 mg/dl, leukocytes 5100/渭l, erythrocytes 5.00 脳 106/渭l, hemoglobin 14.4 g/dl, hematocrit 43.6%, and platelets 263 脳 103/渭l.
The HAL-SJ treatment program was divided into five phases []. Phase 1 consisted of preoperative observation from the day of hospital admission until the day of surgery. The patient鈥檚 thigh circumference and lower leg length were measured preoperatively to adjust the HAL-SJ to the patient鈥檚 physical size, which would ensure appropriate training. We palpated the patient鈥檚 quadriceps muscles (vastus medialis, rectus femoris, and vastus lateralis) and attached electrodes to each muscle to detect the bioelectric potentials of the long axis along the belly of each muscle. We instructed the patient to perform knee extension and to contract her quadriceps. On the basis of these data, we instructed the patient to simulate the knee extension training, which would be performed postoperatively. Specifically, the patient sat with her lower leg hanging down naturally, and the height of the chair was adjusted so that the patient鈥檚 feet were not in contact with the floor. The patient performed ten knee extensions with HAL-SJ assistance, using the muscle that exhibited the largest bioelectric potential amplitude.
Phase 2 involved surgery (day of surgery). The patient underwent OWHTO (Figs. and ) using TomoFix (DePuy Synthes, Bettlach, Switzerland), artificial bone (OSferion60, 尾-tricalcium phosphate; Olympus Terumo Biomaterials, Tokyo, Japan), and biplanar osteotomy, as described by Takeuchi et al. []. The preoperative weight-bearing line (WBL) percentage [], calculated on the basis of an anteroposterior weight-bearing radiograph of the affected leg in full knee extension, was 29.6%. The surgery was planned with a target postoperative WBL percentage of 62.5%. The actual enlarged angle and distance of osteotomy were 5.5 degrees and 7 mm, respectively.
Phase 3 consisted of postoperative observation from day 1 to day 7 postoperatively. For postoperative rehabilitation, partial weight bearing was allowed after a non-weight-bearing period of 2 weeks, and full weight bearing began at 4 weeks postoperatively. The patient received rehabilitation training under the guidance of a physical therapist (ROM exercises and muscle-strengthening training) for 20鈥40 minutes each day, 5 days per week, from the first postoperative day until discharge. For ROM exercises, continuous passive motion training began on the first postoperative day for 1 hour per day and continued every day until discharge. On postoperative day 7, we attached electrodes to the quadriceps muscle to detect the bioelectric potential along the long axis of the rectus femoris muscle belly (Fig. ). Then, the patient was instructed to perform active knee extension exercises that involved contracting her quadriceps, thus simulating training with HAL-SJ (Fig. ).
Phase 4 consisted of HAL-SJ therapy from postoperative day 8 to discharge. The CVC mode of HAL-SJ serves to support the patient鈥檚 voluntary motion on the basis of voluntary muscle activity and the assistive torque provided to the knee joint []. In this study, we used the CVC mode, which allowed the operator to adjust the degree of physical support to maintain the patient鈥檚 comfort while gradually reducing support as training progressed. In addition to the regular rehabilitation program (Fig. ), the patient performed HAL-JS-assisted knee extension exercises while sitting, which consisted of five sets of ten repetitions per set, twice per week (Fig. ). The training was performed six times before the patient was discharged (postoperative days 8, 10, 15, 17, 22, and 24). The mean training duration, including the time required to put on the HAL-SJ, was 15.5 卤 1.4 minutes (15 minutes, 16 minutes, 17 minutes, 16 minutes, 13 minutes, and 16 minutes during training sessions 1, 2, 3, 4, 5, and 6, respectively). There were no adverse events related to the use of HAL-SJ, and the patient was discharged 30 days after the surgery.
Phase 5 consisted of post-HAL-SJ therapy observation from discharge until 3 months after the end of HAL-SJ therapy, during which the following indicators were assessed: EL, assessed as the difference between the maximum knee joint extension angle during passive exercise and that during active exercise; knee pain rated on the visual analogue scale (VAS); isometric knee extension muscle strength (IKEMS); active ROM before surgery, before and after HAL-SJ training, and at 1 and 3 months after the end of training; and the Japanese Orthopaedic Association (JOA) score [] before surgery, at discharge, and at 1 and 3 months after the end of training. Furthermore, we used lateral radiographs to measure the tibial slope angle (TSA) and Insall-Salvati ratio (ISR) as indicators of patellar tendon shortening before surgery and after implant removal at 1 year after the operation [] (Fig. ). Measurement of knee ROM was performed using goniometry, and the landmarks used in the measurements were the greater trochanter of the femur, proximal head of the fibula, and lateral malleolus. Goniometry was used because it has been reported that goniometric measurements of ROM are more reliable than visual observation, with an accuracy of up to 1.0 degree []. The maximal IKEMS of the operated leg was assessed with the patient in a sitting position, with the hips and knees flexed at 90 degrees. A 渭Tas F-1 handheld dynamometer (Anima Corp., Tokyo, Japan) was fixed to the chair, and two measurements were recorded. Each trial lasted 3鈥5 seconds, with 30 seconds of rest between trials. The higher score of two valid trials was recorded. All measurements were performed by a single trained physical therapist to eliminate interobserver variability. The EL, VAS, IKEMS, and ROM results are shown in Table . The EL improved from 3 degrees preoperatively to 0 degrees at the end of the sixth HAL-SJ training session, but it returned to 3 degrees at 1 and 3 months after the end of the training. When we compared results obtained before training against those obtained after each of the six training sessions, we observed that three sessions produced improved EL and three sessions produced improved or relatively constant VAS scores immediately after training. However, for the other three sessions, the patient reported increased pain immediately after training, with the greatest increase in pain reported immediately after the first HAL-SJ training session, when the VAS score was 1.7 times higher immediately after training than before training. The EL improved after training sessions 1 and 3, when the patient reported increased knee pain (expressed as the VAS score). However, the EL did not change after training sessions 2 and 4, when the patient reported less knee pain (improved VAS score immediately after training). The patient did not refuse to undergo training because of increased pain. The IKEMS value was the largest preoperatively (17.6 kgf) and decreased to its lowest value (30% of the preoperative strength) before the first HAL-SJ intervention at 8 days after the operation. The IKEMS remained relatively constant throughout HAL-SJ training but recovered to the preoperative value during follow-up (18.7 and 16.6 kgf at 1 and 3 months, respectively, after completion of HAL-SJ training). The active ROM also recovered to the preoperative value by the end of the sixth HAL-SJ training session. Thereafter, the extension ROM did not change, but the flexion ROM was maintained or improved. The JOA score decreased from 60 points preoperatively to 55 points at discharge, but it improved with time, reaching 65 and 85 points at 1 and 3 months, respectively, after the end of HAL-SJ training. Whereas the TSA was maintained at 13.1 degrees before and after the surgery, the ISR decreased from 1.13 preoperatively to 0.97 postoperatively. At 6 months after surgery, the passive ROM was 0鈥135 degrees, and the JOA score was 90 points. There were no complications throughout the preparation, surgery, or rehabilitation process.

The formula for computing Cockcroft-Gault is given by CrCl = ((140 - age) * adjusted weight * (gender_coefficient)) / (serum creatinine * 72), where the gender_coefficient is 1 if male, and 0.85 if female. The serum creatinine concentration is in mg/dL.
The patient's gender is female, which means that the gender coefficient is 0.85.
The patient is 67 years old. 
The concentration of creatinine is 0.56 mg/dL. 
The formula for computing the patient's BMI is (weight)/(height * height), where weight is the patient's weight in kg and height is the patient's height in m.
The patient's height is 157.0 cm, which is 157.0 cm * 1 m / 100 cm = 1.57 m. The patient's weight is 62.0 kg. The patient's bmi is therefore 62.0 kg / (1.57 m * 1.57 m) = 25.153 kg/m^2.The patient's BMI is 25.2, indicating they are overweight/obese.
Because the patient is overweight/obese, we use the adjusted body weight formula to get the adjusted weight used for Cockroft-Gault Equation. Shown below is the computation for IBW (ideal body weight).
The patient's gender is Female.
The patient's height is 157.0 cm, which is 157.0 cm * 0.393701 in/cm = 61.811 in. 
For females, the ideal body weight (IBW) is calculated as follows:
IBW = 45.5 kg + 2.3 kg * (height (in inches) - 60)
Plugging in the values gives us 45.5 kg + 2.3 kg * (61.811 (in inches) - 60) = 49.665 kg.
Hence, the patient's IBW is 49.665 kg.Shown below is the computation for ABW (adjusted body weight).
To compute the ABW value, apply the following formula: ABW = IBW + 0.4 * (weight (in kg) - IBW (in kg)). ABW = 49.665 kg + 0.4 * (62.0 kg  - 49.665 kg) = 54.599 kg. The patient's adjusted body weight is 54.599 kg.

Using the Cockcroft-Gault equation:
CrCl = ((140 - age) * adjusted weight * gender_coefficient) / (serum creatinine * 72).
Plugging the patient's values gives us ((140 - 67) * 54.599 * 0.85) / (0.56 * 72) = 84.025 mL/min. Hence, the patient's creatinine clearance is 84.025 mL/min.